Hi,
The following patch set provides a different approach to /dev/random which is
called Linux Random Number Generator (LRNG) to collect entropy within the Linux
kernel. The main improvements compared to the existing /dev/random is to provide
sufficient entropy during boot time as well as in virtual environments and when
using SSDs. A secondary design goal is to limit the impact of the entropy
collection on massive parallel systems and also allow the use accelerated
cryptographic primitives. Also, all steps of the entropic data processing are
testable.
The LRNG patch set allows a user to select use of the existing /dev/random or
the LRNG during compile time. As the LRNG provides API and ABI compatible
interfaces to the existing /dev/random implementation, the user can freely chose
the RNG implementation without affecting kernel or user space operations.
This patch set provides early boot-time entropy which implies that no
additional flags to the getrandom(2) system call discussed recently on
the LKML is considered to be necessary. Yet, if additional flags are
introduced to cover special hardware, the LRNG implementation will also
provide them to be fully ABI and API compliant as already discussed on
LKML.
The LRNG is fully compliant to SP800-90B requirements and is shipped with a
full SP800-90B assessment and all required test tools. The existing /dev/random
implementation on the other hand has architectural limitations which
does not easily allow to bring the implementation in compliance with
SP800-90B. The key statement that causes concern is SP800-90B section
3.1.6. This section denies crediting entropy to multiple similar noise
sources. This section explicitly references different noise sources resting
on the timing of events and their derivatives (i.e. it is a direct complaint
to the existing existing /dev/random implementation). Therefore, SP800-90B
now denies the very issue mentioned in [1] with the existing /dev/random
implementation for a long time: crediting entropy to interrupts as well as
crediting entropy to derivatives of interrupts (HID and disk events). This is
not permissible with SP800-90B.
SP800-90B specifies various requirements for the noise source(s) that seed any
DRNG including SP800-90A DRBGs. In about a year from now, SP800-90B will be
mandated for all noise sources that provide entropy to DRBGs as part of a FIPS
140-[2|3] validation or other evaluation types. That means, if we there are no
solutions to comply with the requirements of SP800-90B found till one year
from now, any random number generation and ciphers based on random numbers
on Linux will be considered and treated as not applicable and delivering
no entropy! As /dev/urandom, getrandom(2) and /dev/random are the most
common and prevalent noise sources for DRNGs, all these DRNGs are affected.
This applies across the board for all validations of cryptography executing on
Linux (kernel and user space modules).
For users that are not interested in SP800-90B, the entire code for the
compliance as well as test interfaces can be deselected at compile time.
The design and implementation is driven by a set of goals described in [1]
that the LRNG completely implements. Furthermore, [1] includes the full
assessment of the SP800-90B compliance as well as a comparison with RNG
design suggestions of SP800-90C, and AIS20/31.
The LRNG provides a complete separation of the noise source maintenance
and the collection of entropy into an entropy pool from the post-processing
using a pseudo-random number generator. Different DRNGs are supported,
including:
* The LRNG can be compile-time enabled to replace the existing /dev/random
implementation. When not selecting the LRNG at compile time (default), the
existing /dev/random implementation is built.
* Built-in ChaCha20 DRNG which has no dependency to other kernel
frameworks.
* SP800-90A DRBG using the kernel crypto API including its accelerated
raw cipher implementations. This implies that the output of /dev/random,
getrandom(2), /dev/urandom or get_random_bytes is fully compliant to
SP800-90A.
* Arbitrary DRNGs registered with the kernel crypto API
* Full compliance with SP800-90B which covers the startup and runtime health
tests mandated by SP800-90B as well as providing the test tools and test
interfaces to obtain raw noise data securely. The test tools are provided at
[1].
Booting the patch with the kernel command line option
"dyndbg=file drivers/char/lrng/* +p" generates logs indicating the operation
of the LRNG. Each log is pre-pended with "lrng".
The LRNG has a flexible design by allowing an easy replacement of the
deterministic random number generator component.
Compared to the existing /dev/random implementation, the compiled binary
is smaller when the LRNG is compiled with all options equal to the
existing /dev/random (i.e. only CONFIG_LRNG is set): random.o is 52.5 kBytes
whereas all LRNG object files are in 49 kBytes in size. The fully
SP800-90A/SP800-90B compliant binary code (CONFIG_LRNG,
CONFIG_LRNG_DRNG_SWITCH, CONFIG_LRNG_DRBG, CONFIG_LRNG_HEALTH_TESTS)
uses some 61 kBytes. In addition, the LRNG is about 50% faster in the
performance critical interrupt handler code path compared to the existing
/dev/random implementation.
Full SP800-90B testing is performed on the following systems - details
are given in [2] appendix C:
* x86 KVM virtualized guest 32 and 64 bit systems
* x86 bare metal
* older and newer ARMv7 system
* ARM64
* POWER7 LE and POWER 8 BE
* IBM Z System mainframe
* old MIPS embedded device
[1] https://www.chronox.de/lrng.html - If the patch is accepted, I would
be volunteering to convert the documentation into RST format and
contribute it to the Linux kernel documentation directory.
[2] https://www.chronox.de/lrng/doc/lrng.pdf
Changes (compared to the previous patch set):
* Use of SHA-256 for hashing the entropy pool per default to ensure
the LRNG can be claimed to manage 256 bits of entropy pursuant to
SP800-90B (note, the required CONFIG_CRYPTO_LIB_SHA256 current depends
on CONFIG_CRYPTO due to artificial Kconfig settings - technically
CONFIG_CRYPTO_LIB_SHA256 could be compiled without CONFIG_CRYPTO)
* When using CTR DRBG, use SHA-256 for hashing entropy pool instead of
CMAC AES to fully comply with SP800-90B to the letter of the law
* Correctly use CONFIG_BASE_SMALL in C code
* speed up add_interrupt_randomness if high-resolution time stamp is not
available
* integrate patch a2541dcb51127dc31934ab93bc99ae7df458e41b
* integrate patch f227e3ec3b5cad859ad15666874405e8c1bbc1d4 and ensure
that its associated design concerns documented in [2] section 2.2.5
are addressed
* add test interfaces for Jiffies, interrupt numbers, interrupt flags,
and return instruction pointer supporting integration of patch
f227e3ec3b5cad859ad15666874405e8c1bbc1d4 and systems with a missing
high-resolution timer
As a side node: With the switchable DRNG support offered in this patch set,
the following areas could be removed. As the existing /dev/random has no support
for switchable DRNGs, however, this is not yet feasible though.
* remove lrng_ready_list and all code around it in lrng_interfaces.c
* remove the kernel crypto API RNG API to avoid having two random number
providing APIs - this would imply that all RNGs developed for this API would
be converted to the LRNG interface
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Stephan Mueller (12):
Linux Random Number Generator
LRNG - allocate one DRNG instance per NUMA node
LRNG - sysctls and /proc interface
LRNG - add switchable DRNG support
crypto: DRBG - externalize DRBG functions for LRNG
LRNG - add SP800-90A DRBG extension
LRNG - add kernel crypto API PRNG extension
crypto: provide access to a static Jitter RNG state
LRNG - add Jitter RNG fast noise source
LRNG - add SP800-90B compliant health tests
LRNG - add interface for gathering of raw entropy
LRNG - add power-on and runtime self-tests
MAINTAINERS | 7 +
crypto/drbg.c | 16 +-
crypto/jitterentropy-kcapi.c | 3 +-
crypto/jitterentropy.c | 31 +-
drivers/char/Kconfig | 2 +
drivers/char/Makefile | 9 +-
drivers/char/lrng/Kconfig | 315 +++++++++
drivers/char/lrng/Makefile | 19 +
drivers/char/lrng/lrng_archrandom.c | 93 +++
drivers/char/lrng/lrng_aux.c | 136 ++++
drivers/char/lrng/lrng_chacha20.c | 320 +++++++++
drivers/char/lrng/lrng_chacha20.h | 29 +
drivers/char/lrng/lrng_drbg.c | 259 +++++++
drivers/char/lrng/lrng_drng.c | 409 +++++++++++
drivers/char/lrng/lrng_health.c | 407 +++++++++++
drivers/char/lrng/lrng_interfaces.c | 647 ++++++++++++++++++
drivers/char/lrng/lrng_internal.h | 342 +++++++++
drivers/char/lrng/lrng_jent.c | 88 +++
drivers/char/lrng/lrng_kcapi.c | 321 +++++++++
drivers/char/lrng/lrng_lfsr.h | 152 ++++
drivers/char/lrng/lrng_numa.c | 101 +++
drivers/char/lrng/lrng_pool.c | 589 ++++++++++++++++
drivers/char/lrng/lrng_proc.c | 163 +++++
drivers/char/lrng/lrng_selftest.c | 504 ++++++++++++++
drivers/char/lrng/lrng_sw_noise.c | 155 +++++
drivers/char/lrng/lrng_sw_noise.h | 57 ++
drivers/char/lrng/lrng_switch.c | 189 +++++
drivers/char/lrng/lrng_testing.c | 575 ++++++++++++++++
include/crypto/drbg.h | 7 +
.../crypto/internal}/jitterentropy.h | 3 +
include/linux/lrng.h | 63 ++
31 files changed, 6001 insertions(+), 10 deletions(-)
create mode 100644 drivers/char/lrng/Kconfig
create mode 100644 drivers/char/lrng/Makefile
create mode 100644 drivers/char/lrng/lrng_archrandom.c
create mode 100644 drivers/char/lrng/lrng_aux.c
create mode 100644 drivers/char/lrng/lrng_chacha20.c
create mode 100644 drivers/char/lrng/lrng_chacha20.h
create mode 100644 drivers/char/lrng/lrng_drbg.c
create mode 100644 drivers/char/lrng/lrng_drng.c
create mode 100644 drivers/char/lrng/lrng_health.c
create mode 100644 drivers/char/lrng/lrng_interfaces.c
create mode 100644 drivers/char/lrng/lrng_internal.h
create mode 100644 drivers/char/lrng/lrng_jent.c
create mode 100644 drivers/char/lrng/lrng_kcapi.c
create mode 100644 drivers/char/lrng/lrng_lfsr.h
create mode 100644 drivers/char/lrng/lrng_numa.c
create mode 100644 drivers/char/lrng/lrng_pool.c
create mode 100644 drivers/char/lrng/lrng_proc.c
create mode 100644 drivers/char/lrng/lrng_selftest.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.h
create mode 100644 drivers/char/lrng/lrng_switch.c
create mode 100644 drivers/char/lrng/lrng_testing.c
rename {crypto => include/crypto/internal}/jitterentropy.h (84%)
create mode 100644 include/linux/lrng.h
--
2.26.2
The LRNG sysctl interface provides the same controls as the existing
/dev/random implementation. These sysctls behave identically and are
implemented identically. The goal is to allow a possible merge of the
existing /dev/random implementation with this implementation which
implies that this patch tries have a very close similarity. Yet, all
sysctls are documented at [1].
In addition, it provides the file lrng_type which provides details about
the LRNG:
- the name of the DRNG that produces the random numbers for /dev/random,
/dev/urandom, getrandom(2)
- the hash used to produce random numbers from the entropy pool
- the number of secondary DRNG instances
- indicator whether the LRNG operates SP800-90B compliant
- indicator whether a high-resolution timer is identified - only with a
high-resolution timer the interrupt noise source will deliver sufficient
entropy
- indicator whether the LRNG has been minimally seeded (i.e. is the
secondary DRNG seeded with at least 128 bits of of entropy)
- indicator whether the LRNG has been fully seeded (i.e. is the
secondary DRNG seeded with at least 256 bits of entropy)
[1] https://www.chronox.de/lrng.html
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Marcelo Henrique Cerri <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_interfaces.c | 1 -
drivers/char/lrng/lrng_internal.h | 4 +
drivers/char/lrng/lrng_proc.c | 163 ++++++++++++++++++++++++++++
4 files changed, 168 insertions(+), 1 deletion(-)
create mode 100644 drivers/char/lrng/lrng_proc.c
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index 0a32f22c2c1a..e69c176f0161 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -9,3 +9,4 @@ obj-y += lrng_pool.o lrng_aux.o \
lrng_interfaces.o \
obj-$(CONFIG_NUMA) += lrng_numa.o
+obj-$(CONFIG_SYSCTL) += lrng_proc.o
diff --git a/drivers/char/lrng/lrng_interfaces.c b/drivers/char/lrng/lrng_interfaces.c
index 7fc04e54d834..184108b6e1cb 100644
--- a/drivers/char/lrng/lrng_interfaces.c
+++ b/drivers/char/lrng/lrng_interfaces.c
@@ -34,7 +34,6 @@ static DECLARE_WAIT_QUEUE_HEAD(lrng_write_wait);
static DECLARE_WAIT_QUEUE_HEAD(lrng_init_wait);
static struct fasync_struct *fasync;
-struct ctl_table random_table[];
/********************************** Helper ***********************************/
/* Is the DRNG seed level too low? */
diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h
index 495e00ae5ee1..a52c4cf367e2 100644
--- a/drivers/char/lrng/lrng_internal.h
+++ b/drivers/char/lrng/lrng_internal.h
@@ -117,7 +117,11 @@ void lrng_cc20_init_state_boot(struct chacha20_state *state);
/********************************** /proc *************************************/
+#ifdef CONFIG_SYSCTL
+void lrng_pool_inc_numa_node(void);
+#else
static inline void lrng_pool_inc_numa_node(void) { }
+#endif
/****************************** LRNG interfaces *******************************/
diff --git a/drivers/char/lrng/lrng_proc.c b/drivers/char/lrng/lrng_proc.c
new file mode 100644
index 000000000000..c569a269b07a
--- /dev/null
+++ b/drivers/char/lrng/lrng_proc.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG proc and sysctl interfaces
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#include <linux/lrng.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/sysctl.h>
+#include <linux/uuid.h>
+
+#include "lrng_internal.h"
+
+/*
+ * This function is used to return both the bootid UUID, and random
+ * UUID. The difference is in whether table->data is NULL; if it is,
+ * then a new UUID is generated and returned to the user.
+ *
+ * If the user accesses this via the proc interface, the UUID will be
+ * returned as an ASCII string in the standard UUID format; if via the
+ * sysctl system call, as 16 bytes of binary data.
+ */
+static int lrng_proc_do_uuid(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct ctl_table fake_table;
+ unsigned char buf[64], tmp_uuid[16], *uuid;
+
+ uuid = table->data;
+ if (!uuid) {
+ uuid = tmp_uuid;
+ generate_random_uuid(uuid);
+ } else {
+ static DEFINE_SPINLOCK(bootid_spinlock);
+
+ spin_lock(&bootid_spinlock);
+ if (!uuid[8])
+ generate_random_uuid(uuid);
+ spin_unlock(&bootid_spinlock);
+ }
+
+ sprintf(buf, "%pU", uuid);
+
+ fake_table.data = buf;
+ fake_table.maxlen = sizeof(buf);
+
+ return proc_dostring(&fake_table, write, buffer, lenp, ppos);
+}
+
+static int lrng_proc_do_entropy(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct ctl_table fake_table;
+ int entropy_count;
+
+ entropy_count = lrng_avail_entropy();
+
+ fake_table.data = &entropy_count;
+ fake_table.maxlen = sizeof(entropy_count);
+
+ return proc_dointvec(&fake_table, write, buffer, lenp, ppos);
+}
+
+static int lrng_sysctl_poolsize = LRNG_POOL_SIZE_BITS;
+static int lrng_min_write_thresh;
+static int lrng_max_write_thresh = LRNG_POOL_SIZE_BITS;
+static char lrng_sysctl_bootid[16];
+static int lrng_drng_reseed_max_min;
+
+struct ctl_table random_table[] = {
+ {
+ .procname = "poolsize",
+ .data = &lrng_sysctl_poolsize,
+ .maxlen = sizeof(int),
+ .mode = 0444,
+ .proc_handler = proc_dointvec,
+ },
+ {
+ .procname = "entropy_avail",
+ .maxlen = sizeof(int),
+ .mode = 0444,
+ .proc_handler = lrng_proc_do_entropy,
+ },
+ {
+ .procname = "write_wakeup_threshold",
+ .data = &lrng_write_wakeup_bits,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &lrng_min_write_thresh,
+ .extra2 = &lrng_max_write_thresh,
+ },
+ {
+ .procname = "boot_id",
+ .data = &lrng_sysctl_bootid,
+ .maxlen = 16,
+ .mode = 0444,
+ .proc_handler = lrng_proc_do_uuid,
+ },
+ {
+ .procname = "uuid",
+ .maxlen = 16,
+ .mode = 0444,
+ .proc_handler = lrng_proc_do_uuid,
+ },
+ {
+ .procname = "urandom_min_reseed_secs",
+ .data = &lrng_drng_reseed_max_time,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ .extra1 = &lrng_drng_reseed_max_min,
+ },
+ { }
+};
+
+/* Number of online DRNGs */
+static u32 numa_drngs = 1;
+
+void lrng_pool_inc_numa_node(void)
+{
+ numa_drngs++;
+}
+
+static int lrng_proc_type_show(struct seq_file *m, void *v)
+{
+ struct lrng_drng *lrng_drng_init = lrng_drng_init_instance();
+ unsigned long flags = 0;
+ unsigned char buf[300];
+
+ lrng_drng_lock(lrng_drng_init, &flags);
+ snprintf(buf, sizeof(buf),
+ "DRNG name: %s\n"
+ "Hash for reading entropy pool: %s\n"
+ "DRNG security strength: %d bits\n"
+ "number of DRNG instances: %u\n"
+ "SP800-90B compliance: %s\n"
+ "High-resolution timer: %s\n"
+ "LRNG minimally seeded: %s\n"
+ "LRNG fully seeded: %s\n",
+ lrng_drng_init->crypto_cb->lrng_drng_name(),
+ lrng_drng_init->crypto_cb->lrng_hash_name(),
+ LRNG_DRNG_SECURITY_STRENGTH_BITS, numa_drngs,
+ lrng_sp80090b_compliant() ? "true" : "false",
+ lrng_pool_highres_timer() ? "true" : "false",
+ lrng_state_min_seeded() ? "true" : "false",
+ lrng_state_fully_seeded() ? "true" : "false");
+ lrng_drng_unlock(lrng_drng_init, &flags);
+
+ seq_write(m, buf, strlen(buf));
+
+ return 0;
+}
+
+static int __init lrng_proc_type_init(void)
+{
+ proc_create_single("lrng_type", 0444, NULL, &lrng_proc_type_show);
+ return 0;
+}
+
+module_init(lrng_proc_type_init);
--
2.26.2
Using the LRNG switchable DRNG support, the SP800-90A DRBG extension is
implemented.
The DRBG uses the kernel crypto API DRBG implementation. In addition, it
uses the kernel crypto API SHASH support to provide the hashing
operation.
The DRBG supports the choice of either a CTR DRBG using AES-256, HMAC
DRBG with SHA-512 core or Hash DRBG with SHA-512 core. The used core can
be selected with the module parameter lrng_drbg_type. The default is the
CTR DRBG.
When compiling the DRBG extension statically, the DRBG is loaded at
late_initcall stage which implies that with the start of user space, the
user space interfaces of getrandom(2), /dev/random and /dev/urandom
provide random data produced by an SP800-90A DRBG.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Kconfig | 12 ++
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_drbg.c | 259 ++++++++++++++++++++++++++++++++++
3 files changed, 272 insertions(+)
create mode 100644 drivers/char/lrng/lrng_drbg.c
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
index d3138458fd8b..4ad26fdfbe7e 100644
--- a/drivers/char/lrng/Kconfig
+++ b/drivers/char/lrng/Kconfig
@@ -72,4 +72,16 @@ menuconfig LRNG_DRNG_SWITCH
accessible via the external interfaces. With this configuration
option other DRNGs can be selected and loaded at runtime.
+if LRNG_DRNG_SWITCH
+config LRNG_DRBG
+ tristate "SP800-90A support for the LRNG"
+ depends on CRYPTO
+ select CRYPTO_DRBG_MENU
+ select CRYPTO_SHA512
+ help
+ Enable the SP800-90A DRBG support for the LRNG. Once the
+ module is loaded, output from /dev/random, /dev/urandom,
+ getrandom(2), or get_random_bytes is provided by a DRBG.
+endif # LRNG_DRNG_SWITCH
+
endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index 31cfe87c999e..0d320fcb7b9e 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -11,3 +11,4 @@ obj-y += lrng_pool.o lrng_aux.o \
obj-$(CONFIG_NUMA) += lrng_numa.o
obj-$(CONFIG_SYSCTL) += lrng_proc.o
obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o
+obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o
diff --git a/drivers/char/lrng/lrng_drbg.c b/drivers/char/lrng/lrng_drbg.c
new file mode 100644
index 000000000000..06590438f88f
--- /dev/null
+++ b/drivers/char/lrng/lrng_drbg.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Backend for the LRNG providing the cryptographic primitives using the
+ * kernel crypto API and its DRBG.
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <crypto/drbg.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/lrng.h>
+
+/*
+ * Define a DRBG plus a hash / MAC used to extract data from the entropy pool.
+ * For LRNG_HASH_NAME you can use a hash or a MAC (HMAC or CMAC) of your choice
+ * (Note, you should use the suggested selections below -- using SHA-1 or MD5
+ * is not wise). The idea is that the used cipher primitive can be selected to
+ * be the same as used for the DRBG. I.e. the LRNG only uses one cipher
+ * primitive using the same cipher implementation with the options offered in
+ * the following. This means, if the CTR DRBG is selected and AES-NI is present,
+ * both the CTR DRBG and the selected cmac(aes) use AES-NI.
+ *
+ * The security strengths of the DRBGs are all 256 bits according to
+ * SP800-57 section 5.6.1.
+ *
+ * This definition is allowed to be changed.
+ */
+#ifdef CONFIG_CRYPTO_DRBG_CTR
+static unsigned int lrng_drbg_type = 0;
+#elif defined CONFIG_CRYPTO_DRBG_HMAC
+static unsigned int lrng_drbg_type = 1;
+#elif defined CONFIG_CRYPTO_DRBG_HASH
+static unsigned int lrng_drbg_type = 2;
+#else
+#error "Unknown DRBG in use"
+#endif
+
+/* The parameter must be r/o in sysfs as otherwise races appear. */
+module_param(lrng_drbg_type, uint, 0444);
+MODULE_PARM_DESC(lrng_drbg_type, "DRBG type used for LRNG (0->CTR_DRBG, 1->HMAC_DRBG, 2->Hash_DRBG)");
+
+struct lrng_drbg {
+ const char *hash_name;
+ const char *drbg_core;
+};
+
+static const struct lrng_drbg lrng_drbg_types[] = {
+ { /* CTR_DRBG with AES-256 using derivation function */
+ .hash_name = "sha512",
+ .drbg_core = "drbg_nopr_ctr_aes256",
+ }, { /* HMAC_DRBG with SHA-512 */
+ .hash_name = "sha512",
+ .drbg_core = "drbg_nopr_hmac_sha512",
+ }, { /* Hash_DRBG with SHA-512 using derivation function */
+ .hash_name = "sha512",
+ .drbg_core = "drbg_nopr_sha512"
+ }
+};
+
+struct lrng_hash_info {
+ struct shash_desc shash;
+ char ctx[];
+};
+
+static int lrng_drbg_drng_seed_helper(void *drng, const u8 *inbuf, u32 inbuflen)
+{
+ struct drbg_state *drbg = (struct drbg_state *)drng;
+ LIST_HEAD(seedlist);
+ struct drbg_string data;
+ int ret;
+
+ drbg_string_fill(&data, inbuf, inbuflen);
+ list_add_tail(&data.list, &seedlist);
+ ret = drbg->d_ops->update(drbg, &seedlist, drbg->seeded);
+
+ if (ret >= 0)
+ drbg->seeded = true;
+
+ return ret;
+}
+
+static int lrng_drbg_drng_generate_helper(void *drng, u8 *outbuf, u32 outbuflen)
+{
+ struct drbg_state *drbg = (struct drbg_state *)drng;
+
+ return drbg->d_ops->generate(drbg, outbuf, outbuflen, NULL);
+}
+
+static void *lrng_drbg_drng_alloc(u32 sec_strength)
+{
+ struct drbg_state *drbg;
+ int coreref = -1;
+ bool pr = false;
+ int ret;
+
+ drbg_convert_tfm_core(lrng_drbg_types[lrng_drbg_type].drbg_core,
+ &coreref, &pr);
+ if (coreref < 0)
+ return ERR_PTR(-EFAULT);
+
+ drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
+ if (!drbg)
+ return ERR_PTR(-ENOMEM);
+
+ drbg->core = &drbg_cores[coreref];
+ drbg->seeded = false;
+ ret = drbg_alloc_state(drbg);
+ if (ret)
+ goto err;
+
+ if (sec_strength > drbg_sec_strength(drbg->core->flags)) {
+ pr_err("Security strength of DRBG (%u bits) lower than requested by LRNG (%u bits)\n",
+ drbg_sec_strength(drbg->core->flags) * 8,
+ sec_strength * 8);
+ goto dealloc;
+ }
+
+ if (sec_strength < drbg_sec_strength(drbg->core->flags))
+ pr_warn("Security strength of DRBG (%u bits) higher than requested by LRNG (%u bits)\n",
+ drbg_sec_strength(drbg->core->flags) * 8,
+ sec_strength * 8);
+
+ pr_info("DRBG with %s core allocated\n", drbg->core->backend_cra_name);
+
+ return drbg;
+
+dealloc:
+ if (drbg->d_ops)
+ drbg->d_ops->crypto_fini(drbg);
+ drbg_dealloc_state(drbg);
+err:
+ kfree(drbg);
+ return ERR_PTR(-EINVAL);
+}
+
+static void lrng_drbg_drng_dealloc(void *drng)
+{
+ struct drbg_state *drbg = (struct drbg_state *)drng;
+
+ if (drbg && drbg->d_ops)
+ drbg->d_ops->crypto_fini(drbg);
+ drbg_dealloc_state(drbg);
+ kzfree(drbg);
+ pr_info("DRBG deallocated\n");
+}
+
+static void *lrng_drbg_hash_alloc(const u8 *key, u32 keylen)
+{
+ struct lrng_hash_info *lrng_hash;
+ struct crypto_shash *tfm;
+ int size, ret;
+
+ tfm = crypto_alloc_shash(lrng_drbg_types[lrng_drbg_type].hash_name,
+ 0, 0);
+ if (IS_ERR(tfm)) {
+ pr_err("could not allocate hash %s\n",
+ lrng_drbg_types[lrng_drbg_type].hash_name);
+ return ERR_CAST(tfm);
+ }
+
+ size = sizeof(struct lrng_hash_info) + crypto_shash_descsize(tfm);
+ lrng_hash = kmalloc(size, GFP_KERNEL);
+ if (!lrng_hash) {
+ crypto_free_shash(tfm);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ lrng_hash->shash.tfm = tfm;
+
+ /* If the used hash is no MAC, ignore the ENOSYS return code */
+ ret = crypto_shash_setkey(tfm, key, keylen);
+ if (ret && ret != -ENOSYS) {
+ pr_err("could not set the key for MAC\n");
+ crypto_free_shash(tfm);
+ kfree(lrng_hash);
+ return ERR_PTR(ret);
+ }
+
+ pr_info("Hash %s allocated\n",
+ lrng_drbg_types[lrng_drbg_type].hash_name);
+
+ return lrng_hash;
+}
+
+static void lrng_drbg_hash_dealloc(void *hash)
+{
+ struct lrng_hash_info *lrng_hash = (struct lrng_hash_info *)hash;
+ struct shash_desc *shash = &lrng_hash->shash;
+ struct crypto_shash *tfm = shash->tfm;
+
+ crypto_free_shash(tfm);
+ kfree(lrng_hash);
+ pr_info("Hash deallocated\n");
+}
+
+static u32 lrng_drbg_hash_digestsize(void *hash)
+{
+ struct lrng_hash_info *lrng_hash = (struct lrng_hash_info *)hash;
+ struct shash_desc *shash = &lrng_hash->shash;
+
+ return crypto_shash_digestsize(shash->tfm);
+}
+
+static int lrng_drbg_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest)
+{
+ struct lrng_hash_info *lrng_hash = (struct lrng_hash_info *)hash;
+ struct shash_desc *shash = &lrng_hash->shash;
+
+ return crypto_shash_digest(shash, inbuf, inbuflen, digest);
+}
+
+static const char *lrng_drbg_name(void)
+{
+ return lrng_drbg_types[lrng_drbg_type].drbg_core;
+}
+
+static const char *lrng_hash_name(void)
+{
+ return lrng_drbg_types[lrng_drbg_type].hash_name;
+}
+
+const static struct lrng_crypto_cb lrng_drbg_crypto_cb = {
+ .lrng_drng_name = lrng_drbg_name,
+ .lrng_hash_name = lrng_hash_name,
+ .lrng_drng_alloc = lrng_drbg_drng_alloc,
+ .lrng_drng_dealloc = lrng_drbg_drng_dealloc,
+ .lrng_drng_seed_helper = lrng_drbg_drng_seed_helper,
+ .lrng_drng_generate_helper = lrng_drbg_drng_generate_helper,
+ .lrng_hash_alloc = lrng_drbg_hash_alloc,
+ .lrng_hash_dealloc = lrng_drbg_hash_dealloc,
+ .lrng_hash_digestsize = lrng_drbg_hash_digestsize,
+ .lrng_hash_buffer = lrng_drbg_hash_buffer,
+};
+
+static int __init lrng_drbg_init(void)
+{
+ if (lrng_drbg_type >= ARRAY_SIZE(lrng_drbg_types)) {
+ pr_err("lrng_drbg_type parameter too large (given %u - max: %lu)",
+ lrng_drbg_type,
+ (unsigned long)ARRAY_SIZE(lrng_drbg_types) - 1);
+ return -EAGAIN;
+ }
+ return lrng_set_drng_cb(&lrng_drbg_crypto_cb);
+}
+
+static void __exit lrng_drbg_exit(void)
+{
+ lrng_set_drng_cb(NULL);
+}
+
+late_initcall(lrng_drbg_init);
+module_exit(lrng_drbg_exit);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Stephan Mueller <[email protected]>");
+MODULE_DESCRIPTION("Linux Random Number Generator - SP800-90A DRBG backend");
--
2.26.2
The DRNG switch support allows replacing the DRNG mechanism of the
LRNG. The switching support rests on the interface definition of
include/linux/lrng.h. A new DRNG is implemented by filling in the
interface defined in this header file.
In addition to the DRNG, the extension also has to provide a hash
implementation that is used to hash the entropy pool for random number
extraction.
Note: It is permissible to implement a DRNG whose operations may sleep.
However, the hash function must not sleep.
The switchable DRNG support allows replacing the DRNG at runtime.
However, only one DRNG extension is allowed to be loaded at any given
time. Before replacing it with another DRNG implementation, the possibly
existing DRNG extension must be unloaded.
The switchable DRNG extension activates the new DRNG during load time.
It is expected, however, that such a DRNG switch would be done only once
by an administrator to load the intended DRNG implementation.
It is permissible to compile DRNG extensions either as kernel modules or
statically. The initialization of the DRNG extension should be performed
with a late_initcall to ensure the extension is available when user
space starts but after all other initialization completed.
The initialization is performed by registering the function call data
structure with the lrng_set_drng_cb function. In order to unload the
DRNG extension, lrng_set_drng_cb must be invoked with the NULL
parameter.
The DRNG extension should always provide a security strength that is at
least as strong as LRNG_DRNG_SECURITY_STRENGTH_BITS.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Marcelo Henrique Cerri <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Kconfig | 7 ++
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_switch.c | 189 ++++++++++++++++++++++++++++++++
3 files changed, 197 insertions(+)
create mode 100644 drivers/char/lrng/lrng_switch.c
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
index 059b21d9728c..d3138458fd8b 100644
--- a/drivers/char/lrng/Kconfig
+++ b/drivers/char/lrng/Kconfig
@@ -65,4 +65,11 @@ config LRNG_POOL_SIZE
default 7 if LRNG_POOL_SIZE_65536
default 8 if LRNG_POOL_SIZE_131072
+menuconfig LRNG_DRNG_SWITCH
+ bool "Support DRNG runtime switching"
+ help
+ The Linux RNG per default uses a ChaCha20 DRNG that is
+ accessible via the external interfaces. With this configuration
+ option other DRNGs can be selected and loaded at runtime.
+
endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index e69c176f0161..31cfe87c999e 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -10,3 +10,4 @@ obj-y += lrng_pool.o lrng_aux.o \
obj-$(CONFIG_NUMA) += lrng_numa.o
obj-$(CONFIG_SYSCTL) += lrng_proc.o
+obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o
diff --git a/drivers/char/lrng/lrng_switch.c b/drivers/char/lrng/lrng_switch.c
new file mode 100644
index 000000000000..67eebb3c119f
--- /dev/null
+++ b/drivers/char/lrng/lrng_switch.c
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG DRNG switching support
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/lrng.h>
+
+#include "lrng_internal.h"
+
+static int lrng_drng_switch(struct lrng_drng *drng_store,
+ const struct lrng_crypto_cb *cb, int node)
+{
+ const struct lrng_crypto_cb *old_cb;
+ unsigned long flags = 0;
+ int ret;
+ u8 seed[LRNG_DRNG_SECURITY_STRENGTH_BYTES] __latent_entropy;
+ void *new_drng = cb->lrng_drng_alloc(LRNG_DRNG_SECURITY_STRENGTH_BYTES);
+ void *old_drng, *new_hash, *old_hash;
+ bool sl = false, reset_drng = !lrng_get_available();
+
+ if (IS_ERR(new_drng)) {
+ pr_warn("could not allocate new DRNG for NUMA node %d (%ld)\n",
+ node, PTR_ERR(new_drng));
+ return PTR_ERR(new_drng);
+ }
+
+ /*
+ * The seed potentially used as MAC key is undefined to add some
+ * variation. Yet, the security of the MAC does not rely on the key
+ * being secret. The key is only there to turn a MAC into a hash.
+ * The intention is to allow the specification of CMAC(AES) as "hash"
+ * to limit the dependency to AES when using the CTR DRBG.
+ */
+ new_hash = cb->lrng_hash_alloc(seed, sizeof(seed));
+ if (IS_ERR(new_hash)) {
+ pr_warn("could not allocate new LRNG pool hash (%ld)\n",
+ PTR_ERR(new_hash));
+ cb->lrng_drng_dealloc(new_drng);
+ return PTR_ERR(new_hash);
+ }
+
+ lrng_drng_lock(drng_store, &flags);
+
+ /*
+ * Pull from existing DRNG to seed new DRNG regardless of seed status
+ * of old DRNG -- the entropy state for the DRNG is left unchanged which
+ * implies that als the new DRNG is reseeded when deemed necessary. This
+ * seeding of the new DRNG shall only ensure that the new DRNG has the
+ * same entropy as the old DRNG.
+ */
+ ret = drng_store->crypto_cb->lrng_drng_generate_helper(
+ drng_store->drng, seed, sizeof(seed));
+ lrng_drng_unlock(drng_store, &flags);
+
+ if (ret < 0) {
+ reset_drng = true;
+ pr_warn("getting random data from DRNG failed for NUMA node %d (%d)\n",
+ node, ret);
+ } else {
+ /* seed new DRNG with data */
+ ret = cb->lrng_drng_seed_helper(new_drng, seed, ret);
+ if (ret < 0) {
+ reset_drng = true;
+ pr_warn("seeding of new DRNG failed for NUMA node %d (%d)\n",
+ node, ret);
+ } else {
+ pr_debug("seeded new DRNG of NUMA node %d instance from old DRNG instance\n",
+ node);
+ }
+ }
+
+ mutex_lock(&drng_store->lock);
+ /*
+ * If we switch the DRNG from the initial ChaCha20 DRNG to something
+ * else, there is a lock transition from spin lock to mutex (see
+ * lrng_drng_is_atomic and how the lock is taken in lrng_drng_lock).
+ * Thus, we need to take both locks during the transition phase.
+ */
+ if (lrng_drng_is_atomic(drng_store)) {
+ spin_lock_irqsave(&drng_store->spin_lock, flags);
+ sl = true;
+ }
+
+ if (reset_drng)
+ lrng_drng_reset(drng_store);
+
+ old_drng = drng_store->drng;
+ old_cb = drng_store->crypto_cb;
+ drng_store->drng = new_drng;
+ drng_store->crypto_cb = cb;
+
+ old_hash = drng_store->hash;
+ drng_store->hash = new_hash;
+ pr_info("Entropy pool read-hash allocated for DRNG for NUMA node %d\n",
+ node);
+
+ if (sl)
+ spin_unlock_irqrestore(&drng_store->spin_lock, flags);
+ mutex_unlock(&drng_store->lock);
+
+ /* ChaCha20 serves as atomic instance left untouched. */
+ if (old_drng != &chacha20) {
+ old_cb->lrng_drng_dealloc(old_drng);
+ old_cb->lrng_hash_dealloc(old_hash);
+ }
+
+ pr_info("DRNG of NUMA node %d switched\n", node);
+
+ return 0;
+}
+
+/*
+ * Switch the existing DRNG instances with new using the new crypto callbacks.
+ * The caller must hold the lrng_crypto_cb_update lock.
+ */
+static int lrng_drngs_switch(const struct lrng_crypto_cb *cb)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ struct lrng_drng *lrng_drng_init = lrng_drng_init_instance();
+ int ret = 0;
+
+ /* Update DRNG */
+ if (lrng_drng) {
+ u32 node;
+
+ for_each_online_node(node) {
+ if (lrng_drng[node])
+ ret = lrng_drng_switch(lrng_drng[node], cb,
+ node);
+ }
+ } else {
+ ret = lrng_drng_switch(lrng_drng_init, cb, 0);
+ }
+
+ if (!ret)
+ lrng_set_available();
+
+ return 0;
+}
+
+/**
+ * lrng_set_drng_cb - Register new cryptographic callback functions for DRNG
+ * The registering implies that all old DRNG states are replaced with new
+ * DRNG states.
+ *
+ * @cb: Callback functions to be registered -- if NULL, use the default
+ * callbacks pointing to the ChaCha20 DRNG.
+ *
+ * Return:
+ * * 0 on success
+ * * < 0 on error
+ */
+int lrng_set_drng_cb(const struct lrng_crypto_cb *cb)
+{
+ struct lrng_drng *lrng_drng_init = lrng_drng_init_instance();
+ int ret;
+
+ if (!cb)
+ cb = &lrng_cc20_crypto_cb;
+
+ mutex_lock(&lrng_crypto_cb_update);
+
+ /*
+ * If a callback other than the default is set, allow it only to be
+ * set back to the default callback. This ensures that multiple
+ * different callbacks can be registered at the same time. If a
+ * callback different from the current callback and the default
+ * callback shall be set, the current callback must be deregistered
+ * (e.g. the kernel module providing it must be unloaded) and the new
+ * implementation can be registered.
+ */
+ if ((cb != &lrng_cc20_crypto_cb) &&
+ (lrng_drng_init->crypto_cb != &lrng_cc20_crypto_cb)) {
+ pr_warn("disallow setting new cipher callbacks, unload the old callbacks first!\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = lrng_drngs_switch(cb);
+
+out:
+ mutex_unlock(&lrng_crypto_cb_update);
+ return ret;
+}
+EXPORT_SYMBOL(lrng_set_drng_cb);
--
2.26.2
The test interface allows a privileged process to capture the raw
unconditioned noise that is collected by the LRNG for statistical
analysis. Such testing allows the analysis how much entropy
the interrupt noise source provides on a given platform.
Extracted noise data is not used to seed the LRNG. This
is a test interface and not appropriate for production systems.
Yet, the interface is considered to be sufficiently secured for
production systems.
Access to the data is given through the lrng_raw debugfs file. The
data buffer should be multiples of sizeof(u32) to fill the entire
buffer. Using the option lrng_testing.boot_test=1 the raw noise of
the first 1000 entropy events since boot can be sampled.
This test interface allows generating the data required for
analysis whether the LRNG is in compliance with SP800-90B
sections 3.1.3 and 3.1.4.
In addition, the test interface allows gathering of the conatenated raw
entropy data to verify that the concatenation works appropriately.
This includes sampling of the following raw data:
* high-resolution time stamp
* Jiffies
* IRQ number
* IRQ flags
* return instruction pointer
* array logic batching the high-resolution time stamp
Finally, the execution duration for processing a time stamp can be
obtained with the LRNG raw entropy interface.
If a test interface is not compiled, its code is a noop which has no
impact on the performance.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Kconfig | 124 +++++++
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_testing.c | 575 +++++++++++++++++++++++++++++++
3 files changed, 700 insertions(+)
create mode 100644 drivers/char/lrng/lrng_testing.c
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
index 70eee0f43d8c..5d2f44d07581 100644
--- a/drivers/char/lrng/Kconfig
+++ b/drivers/char/lrng/Kconfig
@@ -163,4 +163,128 @@ config LRNG_APT_CUTOFF
default 325 if !LRNG_APT_BROKEN
default 32 if LRNG_APT_BROKEN
+menuconfig LRNG_TESTING_MENU
+ bool "LRNG testing interfaces"
+ depends on DEBUG_FS
+ help
+ Enable one or more of the following test interfaces.
+
+ If unsure, say N.
+
+if LRNG_TESTING_MENU
+
+config LRNG_RAW_HIRES_ENTROPY
+ bool "Enable entropy test interface to hires timer noise source"
+ default y
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned high resolution time stamp noise that
+ is collected by the LRNG for statistical analysis. Extracted
+ noise data is not used to seed the LRNG.
+
+ The raw noise data can be obtained using the lrng_raw_hires
+ debugfs file. Using the option lrng_testing.boot_raw_hires_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_JIFFIES_ENTROPY
+ bool "Enable entropy test interface to Jiffies noise source"
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned Jiffies that is collected by
+ the LRNG for statistical analysis. This data is used for
+ seeding the LRNG if a high-resolution time stamp is not
+ available. If a high-resolution time stamp is detected,
+ the Jiffies value is not collected by the LRNG and no
+ data is provided via the test interface. Extracted noise
+ data is not used to seed the random number generator.
+
+ The raw noise data can be obtained using the lrng_raw_jiffies
+ debugfs file. Using the option lrng_testing.boot_raw_jiffies_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_IRQ_ENTROPY
+ bool "Enable entropy test interface to IRQ number noise source"
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned interrupt number that is collected by
+ the LRNG for statistical analysis. This data is used for
+ seeding the random32 PRNG external to the LRNG if a
+ high-resolution time stamp is available or it will be used to
+ seed the LRNG otherwise. Extracted noise data is not used to
+ seed the random number generator.
+
+ The raw noise data can be obtained using the lrng_raw_irq
+ debugfs file. Using the option lrng_testing.boot_raw_irq_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_IRQFLAGS_ENTROPY
+ bool "Enable entropy test interface to IRQ flags noise source"
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned interrupt flags that is collected by
+ the LRNG for statistical analysis. This data is used for
+ seeding the random32 PRNG external to the LRNG if a
+ high-resolution time stamp is available or it will be used to
+ seed the LRNG otherwise. Extracted noise data is not used to
+ seed the random number generator.
+
+ The raw noise data can be obtained using the lrng_raw_irqflags
+ debugfs file. Using the option lrng_testing.boot_raw_irqflags_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_RETIP_ENTROPY
+ bool "Enable entropy test interface to RETIP value noise source"
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned return instruction pointer value
+ that is collected by the LRNG for statistical analysis.
+ This data is used for seeding the random32 PRNG external
+ to the LRNG if a high-resolution time stamp is available or
+ it will be used to seed the LRNG otherwise. Extracted noise
+ data is not used to seed the random number generator.
+
+ The raw noise data can be obtained using the lrng_raw_retip
+ debugfs file. Using the option lrng_testing.boot_raw_retip_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_ARRAY
+ bool "Enable test interface to LRNG raw entropy storage array"
+ help
+ The test interface allows a privileged process to capture
+ the raw noise data that is collected by the LRNG
+ in the per-CPU array for statistical analysis. The purpose
+ of this interface is to verify that the array handling code
+ truly only concatenates data and provides the same entropy
+ rate as the raw unconditioned noise source when assessing
+ the collected data byte-wise.
+
+ The data can be obtained using the lrng_raw_array debugfs
+ file. Using the option lrng_testing.boot_raw_array=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_IRQ_PERF
+ bool "Enable LRNG interrupt performance monitor"
+ help
+ With this option, the performance monitor of the LRNG
+ interrupt handling code is enabled. The file provides
+ the execution time of the interrupt handler in
+ cycles.
+
+ The interrupt performance data can be obtained using
+ the lrng_irq_perf debugfs file. Using the option
+ lrng_testing.boot_irq_perf=1 the performance data of
+ the first 1000 entropy events since boot can be sampled.
+
+config LRNG_TESTING
+ bool
+ default y if (LRNG_RAW_ENTROPY || LRNG_RAW_ARRAY || LRNG_IRQ_PERF)
+
+endif #LRNG_TESTING_MENU
+
endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index c3008763dd14..b2ce1979dc4b 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o
obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o
obj-$(CONFIG_LRNG_JENT) += lrng_jent.o
obj-$(CONFIG_LRNG_HEALTH_TESTS) += lrng_health.o
+obj-$(CONFIG_LRNG_TESTING) += lrng_testing.o
diff --git a/drivers/char/lrng/lrng_testing.c b/drivers/char/lrng/lrng_testing.c
new file mode 100644
index 000000000000..77c756e8b0a3
--- /dev/null
+++ b/drivers/char/lrng/lrng_testing.c
@@ -0,0 +1,575 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Linux Random Number Generator (LRNG) testing interfaces
+ *
+ * Copyright (C) 2019 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/workqueue.h>
+#include <asm/errno.h>
+
+#include "lrng_internal.h"
+
+#define LRNG_TESTING_RINGBUFFER_SIZE 1024
+#define LRNG_TESTING_RINGBUFFER_MASK (LRNG_TESTING_RINGBUFFER_SIZE - 1)
+
+struct lrng_testing {
+ u32 lrng_testing_rb[LRNG_TESTING_RINGBUFFER_SIZE];
+ u32 rb_reader;
+ u32 rb_writer;
+ atomic_t lrng_testing_enabled;
+ spinlock_t lock;
+ wait_queue_head_t read_wait;
+};
+
+/*************************** Generic Data Handling ****************************/
+
+/*
+ * boot variable:
+ * 0 ==> No boot test, gathering of runtime data allowed
+ * 1 ==> Boot test enabled and ready for collecting data, gathering runtime
+ * data is disabled
+ * 2 ==> Boot test completed and disabled, gathering of runtime data is
+ * disabled
+ */
+
+static inline void lrng_testing_reset(struct lrng_testing *data)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&data->lock, flags);
+ data->rb_reader = 0;
+ data->rb_writer = 0;
+ spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static inline void lrng_testing_init(struct lrng_testing *data, u32 boot)
+{
+ /*
+ * The boot time testing implies we have a running test. If the
+ * caller wants to clear it, he has to unset the boot_test flag
+ * at runtime via sysfs to enable regular runtime testing
+ */
+ if (boot)
+ return;
+
+ lrng_testing_reset(data);
+ atomic_set(&data->lrng_testing_enabled, 1);
+ pr_warn("Enabling data collection\n");
+}
+
+static inline void lrng_testing_fini(struct lrng_testing *data)
+{
+ atomic_set(&data->lrng_testing_enabled, 0);
+ lrng_testing_reset(data);
+ pr_warn("Disabling data collection\n");
+}
+
+
+static inline bool lrng_testing_store(struct lrng_testing *data, u32 value,
+ u32 *boot)
+{
+ unsigned long flags;
+
+ if (!atomic_read(&data->lrng_testing_enabled) && (*boot != 1))
+ return false;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ /*
+ * Disable entropy testing for boot time testing after ring buffer
+ * is filled.
+ */
+ if (*boot) {
+ if (data->rb_writer > LRNG_TESTING_RINGBUFFER_SIZE) {
+ *boot = 2;
+ pr_warn_once("One time data collection test disabled\n");
+ spin_unlock_irqrestore(&data->lock, flags);
+ return false;
+ }
+
+ if (data->rb_writer == 1)
+ pr_warn("One time data collection test enabled\n");
+ }
+
+ data->lrng_testing_rb[data->rb_writer & LRNG_TESTING_RINGBUFFER_MASK] =
+ value;
+ data->rb_writer++;
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ if (wq_has_sleeper(&data->read_wait))
+ wake_up_interruptible(&data->read_wait);
+
+ return true;
+}
+
+static inline bool lrng_testing_have_data(struct lrng_testing *data)
+{
+ return ((data->rb_writer & LRNG_TESTING_RINGBUFFER_MASK) !=
+ (data->rb_reader & LRNG_TESTING_RINGBUFFER_MASK));
+}
+
+static inline int lrng_testing_reader(struct lrng_testing *data, u32 *boot,
+ u8 *outbuf, u32 outbuflen)
+{
+ unsigned long flags;
+ int collected_data = 0;
+
+ lrng_testing_init(data, *boot);
+
+ while (outbuflen) {
+ spin_lock_irqsave(&data->lock, flags);
+
+ /* We have no data or reached the writer. */
+ if (!data->rb_writer ||
+ (data->rb_writer == data->rb_reader)) {
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ /*
+ * Now we gathered all boot data, enable regular data
+ * collection.
+ */
+ if (*boot) {
+ *boot = 0;
+ goto out;
+ }
+
+ wait_event_interruptible(data->read_wait,
+ lrng_testing_have_data(data));
+ if (signal_pending(current)) {
+ collected_data = -ERESTARTSYS;
+ goto out;
+ }
+
+ continue;
+ }
+
+ /* We copy out word-wise */
+ if (outbuflen < sizeof(u32)) {
+ spin_unlock_irqrestore(&data->lock, flags);
+ goto out;
+ }
+
+ memcpy(outbuf, &data->lrng_testing_rb[data->rb_reader],
+ sizeof(u32));
+ data->rb_reader++;
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ outbuf += sizeof(u32);
+ outbuflen -= sizeof(u32);
+ collected_data += sizeof(u32);
+ }
+
+out:
+ if (!lrng_testing_have_data(data))
+ lrng_testing_fini(data);
+ return collected_data;
+}
+
+static int lrng_testing_extract_user(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos,
+ int (*reader)(u8 *outbuf, u32 outbuflen))
+{
+ loff_t pos = *ppos;
+ u8 *tmp, *tmp_aligned;
+ int ret = 0, large_request = (nbytes > 256);
+
+ if (!nbytes)
+ return 0;
+
+ /*
+ * The intention of this interface is for collecting at least
+ * 1000 samples due to the SP800-90B requirements. So, we make no
+ * effort in avoiding allocating more memory that actually needed
+ * by the user. Hence, we allocate sufficient memory to always hold
+ * that amount of data.
+ */
+ tmp = kmalloc(LRNG_TESTING_RINGBUFFER_SIZE + sizeof(u32), GFP_KERNEL);
+ if (!tmp)
+ return -ENOMEM;
+
+ tmp_aligned = PTR_ALIGN(tmp, sizeof(u32));
+
+ while (nbytes) {
+ int i;
+
+ if (large_request && need_resched()) {
+ if (signal_pending(current)) {
+ if (ret == 0)
+ ret = -ERESTARTSYS;
+ break;
+ }
+ schedule();
+ }
+
+ i = min_t(int, nbytes, LRNG_TESTING_RINGBUFFER_SIZE);
+ i = reader(tmp_aligned, i);
+ if (i <= 0) {
+ if (i < 0)
+ ret = i;
+ break;
+ }
+ if (copy_to_user(buf, tmp_aligned, i)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ nbytes -= i;
+ buf += i;
+ ret += i;
+ }
+
+ kzfree(tmp);
+
+ nbytes -= ret;
+ *ppos = pos + nbytes;
+
+ return ret;
+}
+
+/************** Raw High-Resolution Timer Entropy Data Handling ***************/
+
+#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY
+
+static u32 boot_raw_hires_test = 0;
+module_param(boot_raw_hires_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_hires_test, "Enable gathering boot time high resolution timer entropy of the first entropy events");
+
+static struct lrng_testing lrng_raw_hires = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_hires.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_hires.read_wait)
+};
+
+bool lrng_raw_hires_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_hires, value, &boot_raw_hires_test);
+}
+
+static int lrng_raw_hires_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_hires, &boot_raw_hires_test,
+ outbuf, outbuflen);
+}
+
+static ssize_t lrng_raw_hires_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_hires_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_hires_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_hires_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_HIRES_ENTROPY */
+
+/********************* Raw Jiffies Entropy Data Handling **********************/
+
+#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY
+
+static u32 boot_raw_jiffies_test = 0;
+module_param(boot_raw_jiffies_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_jiffies_test, "Enable gathering boot time high resolution timer entropy of the first entropy events");
+
+static struct lrng_testing lrng_raw_jiffies = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_jiffies.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_jiffies.read_wait)
+};
+
+bool lrng_raw_jiffies_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_jiffies, value,
+ &boot_raw_jiffies_test);
+}
+
+static int lrng_raw_jiffies_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_jiffies, &boot_raw_jiffies_test,
+ outbuf, outbuflen);
+}
+
+static ssize_t lrng_raw_jiffies_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_jiffies_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_jiffies_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_jiffies_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */
+
+/************************** Raw IRQ Data Handling ****************************/
+
+#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY
+
+static u32 boot_raw_irq_test = 0;
+module_param(boot_raw_irq_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_irq_test, "Enable gathering boot time entropy of the first IRQ entropy events");
+
+static struct lrng_testing lrng_raw_irq = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_irq.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_irq.read_wait)
+};
+
+bool lrng_raw_irq_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_irq, value, &boot_raw_irq_test);
+}
+
+static int lrng_raw_irq_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_irq, &boot_raw_irq_test, outbuf,
+ outbuflen);
+}
+
+static ssize_t lrng_raw_irq_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_irq_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_irq_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_irq_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_IRQ_ENTROPY */
+
+/************************ Raw IRQFLAGS Data Handling **************************/
+
+#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY
+
+static u32 boot_raw_irqflags_test = 0;
+module_param(boot_raw_irqflags_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_irqflags_test, "Enable gathering boot time entropy of the first IRQ flags entropy events");
+
+static struct lrng_testing lrng_raw_irqflags = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_irqflags.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_irqflags.read_wait)
+};
+
+bool lrng_raw_irqflags_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_irqflags, value,
+ &boot_raw_irqflags_test);
+}
+
+static int lrng_raw_irqflags_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_irqflags, &boot_raw_irqflags_test,
+ outbuf, outbuflen);
+}
+
+static ssize_t lrng_raw_irqflags_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_irqflags_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_irqflags_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_irqflags_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */
+
+/************************ Raw _RET_IP_ Data Handling **************************/
+
+#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY
+
+static u32 boot_raw_retip_test = 0;
+module_param(boot_raw_retip_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_retip_test, "Enable gathering boot time entropy of the first return instruction pointer entropy events");
+
+static struct lrng_testing lrng_raw_retip = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_retip.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_retip.read_wait)
+};
+
+bool lrng_raw_retip_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_retip, value, &boot_raw_retip_test);
+}
+
+static int lrng_raw_retip_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_retip, &boot_raw_retip_test,
+ outbuf, outbuflen);
+}
+
+static ssize_t lrng_raw_retip_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_retip_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_retip_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_retip_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_RETIP_ENTROPY */
+
+/********************** Raw Entropy Array Data Handling ***********************/
+
+#ifdef CONFIG_LRNG_RAW_ARRAY
+
+static u32 boot_raw_array = 0;
+module_param(boot_raw_array, uint, 0644);
+MODULE_PARM_DESC(boot_raw_array, "Enable gathering boot time raw noise array data of the first entropy events");
+
+static struct lrng_testing lrng_raw_array = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_array.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_array.read_wait)
+};
+
+bool lrng_raw_array_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_array, value, &boot_raw_array);
+}
+
+static int lrng_raw_array_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_array, &boot_raw_array, outbuf,
+ outbuflen);
+}
+
+static ssize_t lrng_raw_array_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_array_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_array_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_array_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_ARRAY */
+
+/******************** Interrupt Performance Data Handling *********************/
+
+#ifdef CONFIG_LRNG_IRQ_PERF
+
+static u32 boot_irq_perf = 0;
+module_param(boot_irq_perf, uint, 0644);
+MODULE_PARM_DESC(boot_irq_perf, "Enable gathering boot time interrupt performance data of the first entropy events");
+
+static struct lrng_testing lrng_irq_perf = {
+ .rb_reader = 0,
+ .rb_reader = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_irq_perf.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_irq_perf.read_wait)
+};
+
+bool lrng_perf_time(u32 start)
+{
+ return lrng_testing_store(&lrng_irq_perf, random_get_entropy() - start,
+ &boot_irq_perf);
+}
+
+static int lrng_irq_perf_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_irq_perf, &boot_irq_perf, outbuf,
+ outbuflen);
+}
+
+static ssize_t lrng_irq_perf_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_irq_perf_reader);
+}
+
+static const struct file_operations lrng_irq_perf_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_irq_perf_read,
+};
+
+#endif /* CONFIG_LRNG_IRQ_PERF */
+
+/**************************************************************************
+ * Debugfs interface
+ **************************************************************************/
+
+static int __init lrng_raw_init(void)
+{
+ struct dentry *lrng_raw_debugfs_root;
+
+ lrng_raw_debugfs_root = debugfs_create_dir(KBUILD_MODNAME, NULL);
+
+#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_hires", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_hires_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_jiffies", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_jiffies_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_irq", 0400, lrng_raw_debugfs_root,
+ NULL, &lrng_raw_irq_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_irqflags", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_irqflags_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_retip", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_retip_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_ARRAY
+ debugfs_create_file_unsafe("lrng_raw_array", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_array_fops);
+#endif
+#ifdef CONFIG_LRNG_IRQ_PERF
+ debugfs_create_file_unsafe("lrng_irq_perf", 0400, lrng_raw_debugfs_root,
+ NULL, &lrng_irq_perf_fops);
+#endif
+
+ return 0;
+}
+
+module_init(lrng_raw_init);
--
2.26.2
Implement health tests for LRNG's slow noise sources as mandated by
SP-800-90B The file contains the following health tests:
- stuck test: The stuck test calculates the first, second and third
discrete derivative of the time stamp to be processed by the LFSR.
Only if all three values are non-zero, the received time delta is
considered to be non-stuck.
- SP800-90B Repetition Count Test (RCT): The LRNG uses an enhanced
version of the RCT specified in SP800-90B section 4.4.1. Instead of
counting identical back-to-back values, the input to the RCT is the
counting of the stuck values during the processing of received
interrupt events. The RCT is applied with alpha=2^-30 compliant to
the recommendation of FIPS 140-2 IG 9.8. During the counting operation,
the LRNG always calculates the RCT cut-off value of C. If that value
exceeds the allowed cut-off value, the LRNG will trigger the health
test failure discussed below. An error is logged to the kernel log
that such RCT failure occurred. This test is only applied and
enforced in FIPS mode, i.e. when the kernel compiled with
CONFIG_CONFIG_FIPS is started with fips=1.
- SP800-90B Adaptive Proportion Test (APT): The LRNG implements the
APT as defined in SP800-90B section 4.4.2. The applied significance
level again is alpha=2^-30 compliant to the recommendation of FIPS
140-2 IG 9.8.
The aforementioned health tests are applied to the first 1,024 time stamps
obtained from interrupt events. In case one error is identified for either
the RCT, or the APT, the collected entropy is invalidated and the
SP800-90B startup health test is restarted.
As long as the SP800-90B startup health test is not completed, all LRNG
random number output interfaces that may block will block and not generate
any data. This implies that only those potentially blocking interfaces are
defined to provide random numbers that are seeded with the interrupt noise
source being SP800-90B compliant. All other output interfaces will not be
affected by the SP800-90B startup test and thus are not considered
SP800-90B compliant.
At runtime, the SP800-90B APT and RCT are applied to each time stamp
generated for a received interrupt. When either the APT and RCT indicates
a noise source failure, the LRNG is reset to a state it has immediately
after boot:
- all entropy counters are set to zero
- the SP800-90B startup tests are re-performed which implies that
getrandom(2) would block again until new entropy was collected
To summarize, the following rules apply:
• SP800-90B compliant output interfaces
- /dev/random
- getrandom(2) system call
- get_random_bytes kernel-internal interface when being triggered by
the callback registered with add_random_ready_callback
• SP800-90B non-compliant output interfaces
- /dev/urandom
- get_random_bytes kernel-internal interface called directly
- randomize_page kernel-internal interface
- get_random_u32 and get_random_u64 kernel-internal interfaces
- get_random_u32_wait, get_random_u64_wait, get_random_int_wait, and
get_random_long_wait kernel-internal interfaces
If either the RCT, or the APT health test fails irrespective whether
during initialization or runtime, the following actions occur:
1. The entropy of the entire entropy pool is invalidated.
2. All DRNGs are reset which imply that they are treated as being
not seeded and require a reseed during next invocation.
3. The SP800-90B startup health test are initiated with all
implications of the startup tests. That implies that from that point
on, new events must be observed and its entropy must be inserted into
the entropy pool before random numbers are calculated from the
entropy pool.
Further details on the SP800-90B compliance and the availability of all
test tools required to perform all tests mandated by SP800-90B are
provided at [1].
The entire health testing code is compile-time configurable.
The patch provides a CONFIG_BROKEN configuration of the APT / RCT cutoff
values which have a high likelihood to trigger the health test failure.
The BROKEN APT cutoff is set to the exact mean of the expected value if
the time stamps are equally distributed (512 time stamps divided by 16
possible values due to using the 4 LSB of the time stamp). The BROKEN
RCT cutoff value is set to 1 which is likely to be triggered during
regular operation.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtmüller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Kconfig | 56 +++++
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_health.c | 407 ++++++++++++++++++++++++++++++++
3 files changed, 464 insertions(+)
create mode 100644 drivers/char/lrng/lrng_health.c
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
index 66a775a8f912..70eee0f43d8c 100644
--- a/drivers/char/lrng/Kconfig
+++ b/drivers/char/lrng/Kconfig
@@ -107,4 +107,60 @@ config LRNG_JENT
time or at runtime with the lrng_base.jitterrng configuration
variable.
+config LRNG_HEALTH_TESTS
+ bool "Enable noise source online health tests"
+ help
+ The online health tests validate the noise source at
+ runtime for fatal errors. These tests include SP800-90B
+ compliant tests which are invoked if the system is booted
+ with fips=1. In case of fatal errors during active
+ SP800-90B tests, the issue is logged and the noise
+ data is discarded. These tests are required for full
+ compliance with SP800-90B.
+
+ If unsure, say Y.
+
+config LRNG_RCT_BROKEN
+ bool "SP800-90B RCT with dangerous low cutoff value"
+ depends on LRNG_HEALTH_TESTS
+ depends on BROKEN
+ default n
+ help
+ This option enables a dangerously low SP800-90B repetitive
+ count test (RCT) cutoff value which makes it very likely
+ that the RCT is triggered to raise a self test failure.
+
+ This option is ONLY intended for developers wanting to
+ test the effectiveness of the SP800-90B RCT health test.
+
+ If unsure, say N.
+
+config LRNG_APT_BROKEN
+ bool "SP800-90B APT with dangerous low cutoff value"
+ depends on LRNG_HEALTH_TESTS
+ depends on BROKEN
+ default n
+ help
+ This option enables a dangerously low SP800-90B adaptive
+ proportion test (APT) cutoff value which makes it very
+ likely that the RCT is triggered to raise a self test
+ failure.
+
+ This option is ONLY intended for developers wanting to
+ test the effectiveness of the SP800-90B APT health test.
+
+ If unsure, say N.
+
+# Default taken from SP800-90B sec 4.4.1 - significance level 2^-30
+config LRNG_RCT_CUTOFF
+ int
+ default 31 if !LRNG_RCT_BROKEN
+ default 1 if LRNG_RCT_BROKEN
+
+# Default taken from SP800-90B sec 4.4.2 - significance level 2^-30
+config LRNG_APT_CUTOFF
+ int
+ default 325 if !LRNG_APT_BROKEN
+ default 32 if LRNG_APT_BROKEN
+
endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index 4f5b6f38f0c4..c3008763dd14 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -14,3 +14,4 @@ obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o
obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o
obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o
obj-$(CONFIG_LRNG_JENT) += lrng_jent.o
+obj-$(CONFIG_LRNG_HEALTH_TESTS) += lrng_health.o
diff --git a/drivers/char/lrng/lrng_health.c b/drivers/char/lrng/lrng_health.c
new file mode 100644
index 000000000000..7817aa6f3357
--- /dev/null
+++ b/drivers/char/lrng/lrng_health.c
@@ -0,0 +1,407 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Linux Random Number Generator (LRNG) Health Testing
+ *
+ * Copyright (C) 2019 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/fips.h>
+#include <linux/module.h>
+
+#include "lrng_internal.h"
+
+/* Stuck Test */
+struct lrng_stuck_test {
+ u32 last_time; /* Stuck test: time of previous IRQ */
+ u32 last_delta; /* Stuck test: delta of previous IRQ */
+ u32 last_delta2; /* Stuck test: 2. time derivation of prev IRQ */
+};
+
+/* Repetition Count Test */
+struct lrng_rct {
+ atomic_t rct_count; /* Number of stuck values */
+};
+
+/* Adaptive Proportion Test */
+struct lrng_apt {
+ /* Data window size */
+#define LRNG_APT_WINDOW_SIZE 512
+ /* LSB of time stamp to process */
+#define LRNG_APT_LSB 16
+#define LRNG_APT_WORD_MASK (LRNG_APT_LSB - 1)
+ atomic_t apt_count; /* APT counter */
+ atomic_t apt_base; /* APT base reference */
+
+ atomic_t apt_trigger;
+ bool apt_base_set; /* Is APT base set? */
+};
+
+/* The health test code must operate lock-less */
+struct lrng_health {
+ struct lrng_rct rct;
+ struct lrng_apt apt;
+
+ bool health_test_enabled;
+
+ /* SP800-90B startup health tests */
+#define LRNG_SP80090B_STARTUP_SAMPLES 1024
+#define LRNG_SP80090B_STARTUP_BLOCKS ((LRNG_SP80090B_STARTUP_SAMPLES + \
+ LRNG_APT_WINDOW_SIZE - 1) / \
+ LRNG_APT_WINDOW_SIZE)
+ bool sp80090b_startup_done;
+ atomic_t sp80090b_startup_blocks;
+};
+
+static struct lrng_health lrng_health = {
+ .rct.rct_count = ATOMIC_INIT(0),
+
+ .apt.apt_count = ATOMIC_INIT(0),
+ .apt.apt_base = ATOMIC_INIT(-1),
+ .apt.apt_trigger = ATOMIC_INIT(LRNG_APT_WINDOW_SIZE),
+ .apt.apt_base_set = false,
+
+ .health_test_enabled = true,
+
+ .sp80090b_startup_blocks = ATOMIC_INIT(LRNG_SP80090B_STARTUP_BLOCKS),
+ .sp80090b_startup_done = false,
+};
+
+static DEFINE_PER_CPU(struct lrng_stuck_test, lrng_stuck_test);
+
+static inline bool lrng_sp80090b_health_requested(void)
+{
+ /* Health tests are only requested in FIPS mode */
+ return fips_enabled;
+}
+
+static inline bool lrng_sp80090b_health_enabled(void)
+{
+ struct lrng_health *health = &lrng_health;
+
+ return lrng_sp80090b_health_requested() && health->health_test_enabled;
+}
+
+/***************************************************************************
+ * SP800-90B Compliance
+ *
+ * If the Linux-RNG is booted into FIPS mode, the following interfaces
+ * provide an SP800-90B compliant noise source:
+ *
+ * * /dev/random
+ * * getrandom(2)
+ * * get_random_bytes when using it in conjunction with
+ * add_random_ready_callback
+ *
+ * All other interfaces, including /dev/urandom or get_random_bytes without
+ * the add_random_ready_callback cannot claim to use an SP800-90B compliant
+ * noise source.
+ ***************************************************************************/
+
+/*
+ * Perform SP800-90B startup testing
+ */
+static inline void lrng_sp80090b_startup(struct lrng_health *health)
+{
+ if (!health->sp80090b_startup_done &&
+ atomic_dec_and_test(&health->sp80090b_startup_blocks)) {
+ health->sp80090b_startup_done = true;
+ pr_info("SP800-90B startup health tests completed\n");
+ lrng_init_ops(0);
+
+ /*
+ * Force a reseed of DRNGs to ensure they are seeded with
+ * entropy that passed the SP800-90B health tests.
+ * As the DRNG always will reseed before generating
+ * random numbers, it does not need a reseed trigger.
+ */
+ lrng_drng_force_reseed();
+ }
+}
+
+/*
+ * Handle failure of SP800-90B startup testing
+ */
+static inline void lrng_sp80090b_startup_failure(struct lrng_health *health)
+{
+ /* Reset of LRNG and its entropy - NOTE: we are in atomic context */
+ lrng_reset();
+
+ /*
+ * Reset the SP800-90B startup test.
+ *
+ * NOTE SP800-90B section 4.3 bullet 4 does not specify what
+ * exactly is to be done in case of failure! Thus, we do what
+ * makes sense, i.e. restarting the health test and thus gating
+ * the output function of /dev/random and getrandom(2).
+ */
+ atomic_set(&health->sp80090b_startup_blocks,
+ LRNG_SP80090B_STARTUP_BLOCKS);
+}
+
+/*
+ * Handle failure of SP800-90B runtime testing
+ */
+static inline void lrng_sp80090b_runtime_failure(struct lrng_health *health)
+{
+ lrng_sp80090b_startup_failure(health);
+ health->sp80090b_startup_done = false;
+}
+
+static inline void lrng_sp80090b_failure(struct lrng_health *health)
+{
+ if (health->sp80090b_startup_done) {
+ pr_err("SP800-90B runtime health test failure - invalidating all existing entropy and initiate SP800-90B startup\n");
+ lrng_sp80090b_runtime_failure(health);
+ } else {
+ pr_err("SP800-90B startup test failure - resetting\n");
+ lrng_sp80090b_startup_failure(health);
+ }
+}
+
+/*
+ * Is the SP800-90B startup testing complete?
+ *
+ * This function is called by the LRNG to determine whether to unblock
+ * a certain user interface. Therefore, only the potentially blocking
+ * user interfaces are considered SP800-90B compliant.
+ */
+bool lrng_sp80090b_startup_complete(void)
+{
+ struct lrng_health *health = &lrng_health;
+
+ return (lrng_sp80090b_health_enabled()) ? health->sp80090b_startup_done:
+ true;
+}
+
+bool lrng_sp80090b_compliant(void)
+{
+ struct lrng_health *health = &lrng_health;
+
+ return lrng_sp80090b_health_enabled() && health->sp80090b_startup_done;
+}
+
+/***************************************************************************
+ * Adaptive Proportion Test
+ *
+ * This test complies with SP800-90B section 4.4.2.
+ ***************************************************************************/
+
+/*
+ * Reset the APT counter
+ *
+ * @health [in] Reference to health state
+ */
+static inline void lrng_apt_reset(struct lrng_health *health,
+ unsigned int time_masked)
+{
+ struct lrng_apt *apt = &health->apt;
+
+ pr_debug("APT value %d for base %d\n",
+ atomic_read(&apt->apt_count), atomic_read(&apt->apt_base));
+
+ /* Reset APT */
+ atomic_set(&apt->apt_count, 0);
+ atomic_set(&apt->apt_base, time_masked);
+}
+
+static inline void lrng_apt_restart(struct lrng_health *health)
+{
+ struct lrng_apt *apt = &health->apt;
+
+ atomic_set(&apt->apt_trigger, LRNG_APT_WINDOW_SIZE);
+}
+
+/*
+ * Insert a new entropy event into APT
+ *
+ * This function does is void as it does not decide about the fate of a time
+ * stamp. An APT failure can only happen at the same time of a stuck test
+ * failure. Thus, the stuck failure will already decide how the time stamp
+ * is handled.
+ *
+ * @health [in] Reference to health state
+ * @now_time [in] Time stamp to process
+ */
+static inline void lrng_apt_insert(struct lrng_health *health,
+ unsigned int now_time)
+{
+ struct lrng_apt *apt = &health->apt;
+
+ if (!lrng_sp80090b_health_requested())
+ return;
+
+ now_time &= LRNG_APT_WORD_MASK;
+
+ /* Initialization of APT */
+ if (!apt->apt_base_set) {
+ atomic_set(&apt->apt_base, now_time);
+ apt->apt_base_set = true;
+ return;
+ }
+
+ if (now_time == (unsigned int)atomic_read(&apt->apt_base)) {
+ u32 apt_val = (u32)atomic_inc_return_relaxed(&apt->apt_count);
+
+ if (apt_val >= CONFIG_LRNG_APT_CUTOFF)
+ lrng_sp80090b_failure(health);
+ }
+
+ if (atomic_dec_and_test(&apt->apt_trigger)) {
+ lrng_apt_restart(health);
+ lrng_apt_reset(health, now_time);
+ lrng_sp80090b_startup(health);
+ }
+}
+
+/***************************************************************************
+ * Repetition Count Test
+ *
+ * The LRNG uses an enhanced version of the Repetition Count Test
+ * (RCT) specified in SP800-90B section 4.4.1. Instead of counting identical
+ * back-to-back values, the input to the RCT is the counting of the stuck
+ * values while filling the entropy pool.
+ *
+ * The RCT is applied with an alpha of 2^-30 compliant to FIPS 140-2 IG 9.8.
+ *
+ * During the counting operation, the LRNG always calculates the RCT
+ * cut-off value of C. If that value exceeds the allowed cut-off value,
+ * the LRNG will invalidate all entropy for the entropy pool which implies
+ * that no data can be extracted from the entropy pool unless new entropy
+ * is received.
+ ***************************************************************************/
+
+/*
+ * Hot code path - Insert data for Repetition Count Test
+ *
+ * @health: Reference to health information
+ * @stuck: Decision of stuck test
+ */
+static inline void lrng_rct(struct lrng_health *health, int stuck)
+{
+ struct lrng_rct *rct = &health->rct;
+
+ if (!lrng_sp80090b_health_requested())
+ return;
+
+ if (stuck) {
+ u32 rct_count = atomic_add_return_relaxed(1, &rct->rct_count);
+
+ pr_debug("RCT count: %u\n", rct_count);
+
+ /*
+ * The cutoff value is based on the following consideration:
+ * alpha = 2^-30 as recommended in FIPS 140-2 IG 9.8.
+ * In addition, we imply an entropy value H of 1 bit as this
+ * is the minimum entropy required to provide full entropy.
+ *
+ * Note, rct_count (which equals to value B in the
+ * pseudo code of SP800-90B section 4.4.1) starts with zero.
+ * Hence we need to subtract one from the cutoff value as
+ * calculated following SP800-90B.
+ */
+ if (rct_count >= CONFIG_LRNG_RCT_CUTOFF) {
+ atomic_set(&rct->rct_count, 0);
+
+ /*
+ * APT must start anew as we consider all previously
+ * recorded data to contain no entropy.
+ */
+ lrng_apt_restart(health);
+
+ lrng_sp80090b_failure(health);
+ }
+ } else {
+ atomic_set(&rct->rct_count, 0);
+ }
+}
+
+/***************************************************************************
+ * Stuck Test
+ *
+ * Checking the:
+ * 1st derivative of the event occurrence (time delta)
+ * 2nd derivative of the event occurrence (delta of time deltas)
+ * 3rd derivative of the event occurrence (delta of delta of time deltas)
+ *
+ * All values must always be non-zero. The stuck test is only valid disabled if
+ * high-resolution time stamps are identified after initialization.
+ ***************************************************************************/
+
+static inline u32 lrng_delta(u32 prev, u32 next)
+{
+ /*
+ * Note that this (unsigned) subtraction does yield the correct value
+ * in the wraparound-case, i.e. when next < prev.
+ */
+ return (next - prev);
+}
+
+/*
+ * Hot code path
+ *
+ * @health: Reference to health information
+ * @now: Event time
+ * @return: 0 event occurrence not stuck (good time stamp)
+ * != 0 event occurrence stuck (reject time stamp)
+ */
+static inline int lrng_irq_stuck(struct lrng_stuck_test *stuck, u32 now_time)
+{
+ u32 delta = lrng_delta(stuck->last_time, now_time);
+ u32 delta2 = lrng_delta(stuck->last_delta, delta);
+ u32 delta3 = lrng_delta(stuck->last_delta2, delta2);
+
+ stuck->last_time = now_time;
+ stuck->last_delta = delta;
+ stuck->last_delta2 = delta2;
+
+ if (!delta || !delta2 || !delta3)
+ return 1;
+
+ return 0;
+}
+
+/***************************************************************************
+ * Health test interfaces
+ ***************************************************************************/
+
+/*
+ * Disable all health tests
+ */
+void lrng_health_disable(void)
+{
+ struct lrng_health *health = &lrng_health;
+
+ health->health_test_enabled = false;
+
+ if (lrng_sp80090b_health_requested())
+ pr_warn("SP800-90B compliance requested but the Linux RNG is NOT SP800-90B compliant\n");
+}
+
+/*
+ * Hot code path - Perform health test on time stamp received from an event
+ *
+ * @now_time Time stamp
+ */
+enum lrng_health_res lrng_health_test(u32 now_time)
+{
+ struct lrng_health *health = &lrng_health;
+ struct lrng_stuck_test *stuck_test = this_cpu_ptr(&lrng_stuck_test);
+ int stuck;
+
+ if (!health->health_test_enabled)
+ return lrng_health_pass;
+
+ lrng_apt_insert(health, now_time);
+
+ stuck = lrng_irq_stuck(stuck_test, now_time);
+ lrng_rct(health, stuck);
+ if (stuck) {
+ /* SP800-90B disallows using a failing health test time stamp */
+ return lrng_sp80090b_health_requested() ?
+ lrng_health_fail_drop : lrng_health_fail_use;
+ }
+
+ return lrng_health_pass;
+}
--
2.26.2
In an effort to provide a flexible implementation for a random number
generator that also delivers entropy during early boot time, allows
replacement of the deterministic random number generation mechanism,
implement the various components in separate code for easier
maintenance, and provide compliance to SP800-90[A|B|C], introduce
the Linux Random Number Generator (LRNG) framework.
The general design is as follows. Additional implementation details
are given in [1]. The LRNG consists of the following components:
1. The LRNG implements a DRNG. The DRNG always generates the
requested amount of output. When using the SP800-90A terminology
it operates without prediction resistance. The secondary DRNG
maintains a counter of how many bytes were generated since last
re-seed and a timer of the elapsed time since last re-seed. If either
the counter or the timer reaches a threshold, the secondary DRNG is
seeded from the entropy pool.
In case the Linux kernel detects a NUMA system, one secondary DRNG
instance per NUMA node is maintained.
2. The DRNG is seeded by concatenating the data from the
following sources:
(a) the output of the entropy pool,
(b) the Jitter RNG if available and enabled, and
(c) the CPU-based noise source such as Intel RDRAND if available and
enabled.
The entropy estimate of the data of all noise sources are added to
form the entropy estimate of the data used to seed the DRNG with.
The LRNG ensures, however, that the DRNG after seeding is at
maximum the security strength of the DRNG.
The LRNG is designed such that none of these noise sources can dominate
the other noise sources to provide seed data to the DRNG during due to
the following:
(a) During boot time, the amount of received interrupts are the trigger
points to (re)seed the DRNG.
(b) At runtime, the available entropy from the slow noise source is
concatenated with a pre-defined amount of data from the fast noise
sources. In addition, each DRNG reseed operation triggers external
noise source providers to deliver one block of data.
3. The entropy pool accumulates entropy obtained from certain events,
which will henceforth be collectively called "slow noise sources".
The entropy pool collects noise data from slow noise sources. Any data
received by the LRNG from the slow noise sources is inserted into the
entropy pool using an LFSR with a primitive and irreducible polynomial.
The following sources of entropy are used:
(a) When an interrupt occurs, the high-resolution time stamp is mixed
into the LFSR. This time stamp is credited with heuristically implied
entropy.
(b) HID event data like the key stroke or the mouse coordinates are
mixed into the LFSR. This data is not credited with entropy by the LRNG.
(c) Device drivers may provide data that is mixed into the LFSR. This
data is not credited with entropy by the LRNG.
(d) After the entropy pool is ``read'' by the DRNG, the data
used to seed the DRNG is mixed back into the entropy pool to
stir the pool. This data is not credited with entropy by the LRNG.
Any data provided from user space by either writing to /dev/random,
/dev/urandom or the IOCTL of RNDADDENTROPY on both device files
are always injected into the entropy pool.
In addition, when a hardware random number generator covered by the
Linux kernel HW generator framework wants to deliver random numbers,
it is injected into the entropy pool as well. HW generator noise source
is handled separately from the other noise source due to the fact that
the HW generator framework may decide by itself when to deliver data
whereas the other noise sources always requested for data driven by the
LRNG operation. Similarly any user space provided data is inserted into
the entropy pool.
When the DRNG requires data from the entropy pool, the entire
entropy pool is processed with an SP800-90A section 10.3.1 compliant
hash_df function to generate random numbers.
To speed up the interrupt handling code of the LRNG, the time stamp
collected for an interrupt event is truncated to the 8 least
significant bits. 64 truncated time stamps are concatenated and then
jointly inserted into the LFSR. During boot time, until the fully seeded
stage is reached, each time stamp with its 32 least significant bits is
inserted into the LFSR at the time of arrival.
The LRNG allows the DRNG mechanism to be changed at runtime. Per default,
a ChaCha20-based DRNG is used. The ChaCha20-DRNG implemented for the
LRNG is also provided as a stand-alone user space deterministic random
number generator. The LRNG also offers an SP800-90A DRBG based on the
Linux kernel crypto API DRBG implementation.
The processing of entropic data from the noise source before injecting
them into the DRNG is performed with the following mathematical
operations:
1. LFSR: The 8 least significant bits of the time stamp data received
from the interrupts are processed with an LFSR. That LFSR is implemented
identically to the LSFR used in the existing /dev/random implementation
except that it is capable of processing an entire word and that a
different polynomial is used. The reason for the different polynomial
is performance in a performance sensitive code section, the interrupt
handler. The chosen polynomials have 4 taps. Also, this LFSR-approach
is used in the OpenBSD /dev/random equivalent.
2. Concatenation: The temporary seed buffer used to seed the DRNG is
a concatenation of parts of the entropy pool data, and the CPU noise
source output.
The DRNG always tries to seed itself with 256 bits of entropy, except
during boot. In any case, if the noise sources cannot deliver that
amount, the available entropy is used and the DRNG keeps track on how
much entropy it was seeded with. The entropy implied by the LRNG
available in the entropy pool may be too conservative. To ensure
that during boot time all available entropy from the entropy pool is
transferred to the DRNG, the hash_df function always generates 256
data bits during boot to seed the DRNG. During boot, the DRNG is
seeded as follows:
1. The DRNG is reseeded from the entropy pool and potentially the fast
noise sources if the entropy pool has collected at least 32 bits of
entropy from the interrupt noise source. The goal of this step is to
ensure that the DRNG receives some initial entropy as early as
possible. In addition it receives the entropy available from
the fast noise sources.
2. The DRNG is reseeded from the entropy pool and potentially the fast
noise sources if all noise sources collectively can provide at least
128 bits of entropy.
3. The DRNG is reseeded from the entropy pool and potentially the fast
noise sources if all noise sources collectivel can provide at least 256
bits.
At the time of the reseeding steps, the DRNG requests as much entropy as
is available in order to skip certain steps and reach the seeding level
of 256 bits. This may imply that one or more of the aforementioned steps
are skipped.
In all listed steps, the DRNG is (re)seeded with a number of random
bytes from the entropy pool that is at most the amount of entropy
present in the entropy pool. This means that when the entropy pool
contains 128 or 256 bits of entropy, the DRNG is seeded with that
amount of entropy as well.
Before the DRNG is seeded with 256 bits of entropy in step 3,
requests of random data from /dev/random are not processed.
The hash_df operation providing random data from the entropy pool will
always require that all entropy sources collectively can deliver at
least 129 entropy bits as configured with (128 bits of entropy for
seeding plus one bit of entropy that is lost with the post
processing as defined in SP800-90B).
The DRNG operates as deterministic random number generator with the
following properties:
* The maximum number of random bytes that can be generated with one
DRNG generate operation is limited to 4096 bytes. When longer random
numbers are requested, multiple DRNG generate operations are performed.
The ChaCha20 DRNG as well as the SP800-90A DRBGs implement an update of
their state after completing a generate request for backtracking
resistance.
* The secondary DRNG is reseeded with whatever entropy is available –
in the worst case where no additional entropy can be provided by the
noise sources, the DRNG is not re-seeded and continues its operation
to try to reseed again after again the expiry of one of these thresholds:
- If the last reseeding of the secondary DRNG is more than 600 seconds
ago, or
- 2^20 DRNG generate operations are performed, whatever comes first, or
- the secondary DRNG is forced to reseed before the next generation of
random numbers if data has been injected into the LRNG by writing data
into /dev/random or /dev/urandom.
The chosen values prevent high-volume requests from user space to cause
frequent reseeding operations which drag down the performance of the
DRNG.
With the automatic reseeding after 600 seconds, the LRNG is triggered
to reseed itself before the first request after a suspend that put the
hardware to sleep for longer than 600 seconds.
The LRNG uses the following runtime memory using the currently
smallest configuration:
* 576 bytes (512 bytes for the entropy pool and 64 for the entropy pool
meta data) for the entropy pool management
* 64 bytes per CPU for the time stamp array
To support smaller devices including IoT environments, this patch
allows reducing the runtime memory footprint of the LRNG at compile
time by selecting smaller entropy pool sizes.
The entropy pool has support for sizes of 256, 128 and 64 bytes supported
by primitive and irreducible polynomials.
The time stamp array is reduced to one atomic_t variable per CPU, i.e.
4 bytes when CONFIG_BASE_SMALL is selected during kernel
configuration. This implies that after the receipt of 4 interrupts on
one CPU, the data is injected into the LFSR. Depending on the behavior
of the CPU caches, this may imply that the average interrupt handler
execution time increases a bit, since instead of injecting 8 atomic_t
values at one given time into the LFSR, only one is processed which
may incur cache misses.
When selecting the compilation of a kernel for a small environment,
prevent the allocation of a buffer up to 4096 bytes to serve user space
requests. In this case, the stack variable of 64 bytes is used to serve
all user space requests.
The LRNG has the following properties:
* internal noise source: interrupts timing with fast boot time seeding
* high performance of interrupt handling code: The LRNG impact on the
interrupt handling has been reduced to a minimum. On one example
system, the LRNG interrupt handling code executes within an average
of 65 cycles whereas the existing /dev/random on the same device
takes about 97 cycles when measuring the execution time of
add_interrupt_randomness().
* lockless LFSR to collect raw entropy supporing concurrency-free
use of massive parallel systems
* use of standalone ChaCha20 based RNG with the option to use a
different DRNG selectable at compile time
* "atomic" seeding of secondary DRBG to ensure full entropy transport
* instantiate one DRNG per NUMA node
* support for runtime switchable output DRNGs
* use of only well-defined entropy-preserving operations to collect,
compress and forward entropy: concatenation, LFSR, SP800-90A hash_df
function
* compile-time selectable entropy pool size: the choice also
uses the applicable LFSR polynomial to maintain the entropy pool
size
* support of small systems by allowing the reduction of the
runtime memory needs
Further details including the rationale for the design choices and
properties of the LRNG together with testing is provided at [1].
In addition, the documentation explains the conducted regression
tests to verify that the LRNG is API and ABI compatible with the
existing /dev/random implementation.
[1] https://www.chronox.de/lrng.html
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Mathematical aspects Reviewed-by: "Peter, Matthias" <[email protected]>
Reviewed-by: Marcelo Henrique Cerri <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtmüller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
MAINTAINERS | 7 +
drivers/char/Kconfig | 2 +
drivers/char/Makefile | 9 +-
drivers/char/lrng/Kconfig | 68 +++
drivers/char/lrng/Makefile | 9 +
drivers/char/lrng/lrng_archrandom.c | 93 ++++
drivers/char/lrng/lrng_aux.c | 136 ++++++
drivers/char/lrng/lrng_chacha20.c | 320 ++++++++++++++
drivers/char/lrng/lrng_chacha20.h | 29 ++
drivers/char/lrng/lrng_drng.c | 409 ++++++++++++++++++
drivers/char/lrng/lrng_interfaces.c | 648 ++++++++++++++++++++++++++++
drivers/char/lrng/lrng_internal.h | 333 ++++++++++++++
drivers/char/lrng/lrng_lfsr.h | 152 +++++++
drivers/char/lrng/lrng_pool.c | 589 +++++++++++++++++++++++++
drivers/char/lrng/lrng_sw_noise.c | 155 +++++++
drivers/char/lrng/lrng_sw_noise.h | 57 +++
include/linux/lrng.h | 63 +++
17 files changed, 3078 insertions(+), 1 deletion(-)
create mode 100644 drivers/char/lrng/Kconfig
create mode 100644 drivers/char/lrng/Makefile
create mode 100644 drivers/char/lrng/lrng_archrandom.c
create mode 100644 drivers/char/lrng/lrng_aux.c
create mode 100644 drivers/char/lrng/lrng_chacha20.c
create mode 100644 drivers/char/lrng/lrng_chacha20.h
create mode 100644 drivers/char/lrng/lrng_drng.c
create mode 100644 drivers/char/lrng/lrng_interfaces.c
create mode 100644 drivers/char/lrng/lrng_internal.h
create mode 100644 drivers/char/lrng/lrng_lfsr.h
create mode 100644 drivers/char/lrng/lrng_pool.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.h
create mode 100644 include/linux/lrng.h
diff --git a/MAINTAINERS b/MAINTAINERS
index deaafb617361..74f6fd1ba1ec 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10084,6 +10084,13 @@ F: Documentation/litmus-tests/
F: Documentation/memory-barriers.txt
F: tools/memory-model/
+LINUX RANDOM NUMBER GENERATOR (LRNG) DRIVER
+M: Stephan Mueller <[email protected]>
+S: Maintained
+W: https://www.chronox.de/lrng.html
+F: drivers/char/lrng/*
+F: include/linux/lrng.h
+
LIS3LV02D ACCELEROMETER DRIVER
M: Eric Piel <[email protected]>
S: Maintained
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index b1bd336761b1..8a5b8a2db2c7 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -470,6 +470,8 @@ config ADI
and SSM (Silicon Secured Memory). Intended consumers of this
driver include crash and makedumpfile.
+source "drivers/char/lrng/Kconfig"
+
endmenu
config RANDOM_TRUST_CPU
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index ffce287ef415..2110d3e28cf2 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -3,7 +3,14 @@
# Makefile for the kernel character device drivers.
#
-obj-y += mem.o random.o
+obj-y += mem.o
+
+ifeq ($(CONFIG_LRNG),y)
+ obj-y += lrng/
+else
+ obj-y += random.o
+endif
+
obj-$(CONFIG_TTY_PRINTK) += ttyprintk.o
obj-y += misc.o
obj-$(CONFIG_ATARI_DSP56K) += dsp56k.o
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
new file mode 100644
index 000000000000..059b21d9728c
--- /dev/null
+++ b/drivers/char/lrng/Kconfig
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Linux Random Number Generator configuration
+#
+
+menuconfig LRNG
+ bool "Linux Random Number Generator"
+ select CRYPTO_LIB_SHA256 if CRYPTO
+ help
+ The Linux Random Number Generator (LRNG) is the replacement
+ of the existing /dev/random provided with drivers/char/random.c.
+ It generates entropy from different noise sources and
+ delivers significant entropy during boot.
+
+if LRNG
+
+choice
+ prompt "LRNG Entropy Pool Size"
+ default LRNG_POOL_SIZE_4096
+ help
+ Select the size of the LRNG entropy pool. The size of the
+ entropy pool is relevant for the amount of entropy that
+ the LRNG can maintain as a maximum. The larger the size
+ of the entropy pool is the more entropy can be maintained
+ but the less often older entropic values are overwritten
+ with new entropy.
+
+ config LRNG_POOL_SIZE_512
+ bool "512 bits"
+
+ config LRNG_POOL_SIZE_1024
+ bool "1024 bits"
+
+ config LRNG_POOL_SIZE_2048
+ bool "2048 bits"
+
+ config LRNG_POOL_SIZE_4096
+ bool "4096 bits (default)"
+
+ config LRNG_POOL_SIZE_8192
+ bool "8192 bits"
+
+ config LRNG_POOL_SIZE_16384
+ bool "16384 bits"
+
+ config LRNG_POOL_SIZE_32768
+ bool "32768 bits"
+
+ config LRNG_POOL_SIZE_65536
+ bool "65536 bits"
+
+ config LRNG_POOL_SIZE_131072
+ bool "131072 bits"
+endchoice
+
+config LRNG_POOL_SIZE
+ int
+ default 0 if LRNG_POOL_SIZE_512
+ default 1 if LRNG_POOL_SIZE_1024
+ default 2 if LRNG_POOL_SIZE_2048
+ default 3 if LRNG_POOL_SIZE_4096
+ default 4 if LRNG_POOL_SIZE_8192
+ default 5 if LRNG_POOL_SIZE_16384
+ default 6 if LRNG_POOL_SIZE_32768
+ default 7 if LRNG_POOL_SIZE_65536
+ default 8 if LRNG_POOL_SIZE_131072
+
+endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
new file mode 100644
index 000000000000..1d2a0211973d
--- /dev/null
+++ b/drivers/char/lrng/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux Random Number Generator.
+#
+
+obj-y += lrng_pool.o lrng_aux.o \
+ lrng_sw_noise.o lrng_archrandom.o \
+ lrng_drng.o lrng_chacha20.o \
+ lrng_interfaces.o \
diff --git a/drivers/char/lrng/lrng_archrandom.c b/drivers/char/lrng/lrng_archrandom.c
new file mode 100644
index 000000000000..5e81c4e856d5
--- /dev/null
+++ b/drivers/char/lrng/lrng_archrandom.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Fast Noise Source: CPU-based noise source
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/random.h>
+
+#include "lrng_internal.h"
+
+/*
+ * Estimated entropy of data is a 32th of LRNG_DRNG_SECURITY_STRENGTH_BITS.
+ * As we have no ability to review the implementation of those noise sources,
+ * it is prudent to have a conservative estimate here.
+ */
+#define LRNG_ARCHRANDOM_DEFAULT_STRENGTH (LRNG_DRNG_SECURITY_STRENGTH_BITS>>5)
+#define LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH LRNG_DRNG_SECURITY_STRENGTH_BITS
+#ifdef CONFIG_RANDOM_TRUST_CPU
+static u32 archrandom = LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH;
+#else
+static u32 archrandom = LRNG_ARCHRANDOM_DEFAULT_STRENGTH;
+#endif
+module_param(archrandom, uint, 0644);
+MODULE_PARM_DESC(archrandom, "Entropy in bits of 256 data bits from CPU noise source (e.g. RDRAND)");
+
+static int __init lrng_parse_trust_cpu(char *arg)
+{
+ int ret;
+ bool trust_cpu = false;
+
+ ret = kstrtobool(arg, &trust_cpu);
+ if (ret)
+ return ret;
+
+ if (trust_cpu)
+ archrandom = LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH;
+ else
+ archrandom = LRNG_ARCHRANDOM_DEFAULT_STRENGTH;
+
+ return 0;
+}
+early_param("random.trust_cpu", lrng_parse_trust_cpu);
+
+/**
+ * lrng_get_arch() - Get CPU noise source entropy
+ *
+ * @outbuf: buffer to store entropy of size LRNG_DRNG_SECURITY_STRENGTH_BYTES
+ *
+ * Return:
+ * * > 0 on success where value provides the added entropy in bits
+ * * 0 if no fast source was available
+ */
+u32 lrng_get_arch(u8 *outbuf)
+{
+ u32 i, ent_bits = archrandom;
+
+ /* operate on full blocks */
+ BUILD_BUG_ON(LRNG_DRNG_SECURITY_STRENGTH_BYTES % sizeof(unsigned long));
+ /* ensure we have aligned buffers */
+ BUILD_BUG_ON(LRNG_KCAPI_ALIGN % sizeof(unsigned long));
+
+ if (!ent_bits)
+ return 0;
+
+ for (i = 0; i < LRNG_DRNG_SECURITY_STRENGTH_BYTES;
+ i += sizeof(unsigned long)) {
+ if (!arch_get_random_seed_long((unsigned long *)(outbuf + i)) &&
+ !arch_get_random_long((unsigned long *)(outbuf + i))) {
+ archrandom = 0;
+ return 0;
+ }
+ }
+
+ /* Obtain entropy statement -- cap entropy to buffer size in bits */
+ ent_bits = min_t(u32, ent_bits, LRNG_DRNG_SECURITY_STRENGTH_BITS);
+ pr_debug("obtained %u bits of entropy from CPU RNG noise source\n",
+ ent_bits);
+ return ent_bits;
+}
+
+u32 lrng_slow_noise_req_entropy(u32 required_entropy_bits)
+{
+ u32 arch_ent_bits = min_t(u32, archrandom,
+ LRNG_DRNG_SECURITY_STRENGTH_BITS);
+ u32 fast_noise_entropy = arch_ent_bits + lrng_jent_entropylevel();
+
+ if (fast_noise_entropy > required_entropy_bits)
+ return 0;
+ return (required_entropy_bits - fast_noise_entropy);
+}
diff --git a/drivers/char/lrng/lrng_aux.c b/drivers/char/lrng/lrng_aux.c
new file mode 100644
index 000000000000..9f46c5707517
--- /dev/null
+++ b/drivers/char/lrng/lrng_aux.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG auxiliary interfaces
+ *
+ * Copyright (C) 2019 Stephan Mueller <[email protected]>
+ * Copyright (C) 2017 Jason A. Donenfeld <[email protected]>. All
+ * Rights Reserved.
+ * Copyright (C) 2016 Jason Cooper <[email protected]>
+ */
+
+#include <linux/mm.h>
+#include <linux/random.h>
+
+#include "lrng_internal.h"
+
+struct batched_entropy {
+ union {
+ u64 entropy_u64[LRNG_DRNG_BLOCKSIZE / sizeof(u64)];
+ u32 entropy_u32[LRNG_DRNG_BLOCKSIZE / sizeof(u32)];
+ };
+ unsigned int position;
+ spinlock_t batch_lock;
+};
+
+/*
+ * Get a random word for internal kernel use only. The quality of the random
+ * number is as good as /dev/urandom, but there is no backtrack protection,
+ * with the goal of being quite fast and not depleting entropy.
+ */
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64) = {
+ .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u64.lock),
+};
+
+u64 get_random_u64(void)
+{
+ u64 ret;
+ unsigned long flags;
+ struct batched_entropy *batch;
+
+ lrng_debug_report_seedlevel("get_random_u64");
+
+ batch = raw_cpu_ptr(&batched_entropy_u64);
+ spin_lock_irqsave(&batch->batch_lock, flags);
+ if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) {
+ lrng_drng_get_atomic((u8 *)batch->entropy_u64,
+ LRNG_DRNG_BLOCKSIZE);
+ batch->position = 0;
+ }
+ ret = batch->entropy_u64[batch->position++];
+ spin_unlock_irqrestore(&batch->batch_lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(get_random_u64);
+
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32) = {
+ .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u32.lock),
+};
+
+u32 get_random_u32(void)
+{
+ u32 ret;
+ unsigned long flags;
+ struct batched_entropy *batch;
+
+ lrng_debug_report_seedlevel("get_random_u32");
+
+ batch = raw_cpu_ptr(&batched_entropy_u32);
+ spin_lock_irqsave(&batch->batch_lock, flags);
+ if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) {
+ lrng_drng_get_atomic((u8 *)batch->entropy_u32,
+ LRNG_DRNG_BLOCKSIZE);
+ batch->position = 0;
+ }
+ ret = batch->entropy_u32[batch->position++];
+ spin_unlock_irqrestore(&batch->batch_lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(get_random_u32);
+
+/*
+ * It's important to invalidate all potential batched entropy that might
+ * be stored before the crng is initialized, which we can do lazily by
+ * simply resetting the counter to zero so that it's re-extracted on the
+ * next usage.
+ */
+void invalidate_batched_entropy(void)
+{
+ int cpu;
+ unsigned long flags;
+
+ for_each_possible_cpu(cpu) {
+ struct batched_entropy *batched_entropy;
+
+ batched_entropy = per_cpu_ptr(&batched_entropy_u32, cpu);
+ spin_lock_irqsave(&batched_entropy->batch_lock, flags);
+ batched_entropy->position = 0;
+ spin_unlock(&batched_entropy->batch_lock);
+
+ batched_entropy = per_cpu_ptr(&batched_entropy_u64, cpu);
+ spin_lock(&batched_entropy->batch_lock);
+ batched_entropy->position = 0;
+ spin_unlock_irqrestore(&batched_entropy->batch_lock, flags);
+ }
+}
+
+/**
+ * randomize_page - Generate a random, page aligned address
+ * @start: The smallest acceptable address the caller will take.
+ * @range: The size of the area, starting at @start, within which the
+ * random address must fall.
+ *
+ * If @start + @range would overflow, @range is capped.
+ *
+ * NOTE: Historical use of randomize_range, which this replaces, presumed that
+ * @start was already page aligned. We now align it regardless.
+ *
+ * Return: A page aligned address within [start, start + range). On error,
+ * @start is returned.
+ */
+unsigned long randomize_page(unsigned long start, unsigned long range)
+{
+ if (!PAGE_ALIGNED(start)) {
+ range -= PAGE_ALIGN(start) - start;
+ start = PAGE_ALIGN(start);
+ }
+
+ if (start > ULONG_MAX - range)
+ range = ULONG_MAX - start;
+
+ range >>= PAGE_SHIFT;
+
+ if (range == 0)
+ return start;
+
+ return start + (get_random_long() % range << PAGE_SHIFT);
+}
diff --git a/drivers/char/lrng/lrng_chacha20.c b/drivers/char/lrng/lrng_chacha20.c
new file mode 100644
index 000000000000..9da139d89959
--- /dev/null
+++ b/drivers/char/lrng/lrng_chacha20.c
@@ -0,0 +1,320 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Backend for the LRNG providing the cryptographic primitives using
+ * ChaCha20 cipher implementations.
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <crypto/chacha.h>
+#include <crypto/sha.h>
+#include <linux/lrng.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+
+#include "lrng_chacha20.h"
+#include "lrng_internal.h"
+
+/******************************* ChaCha20 DRNG *******************************/
+
+#define CHACHA_BLOCK_WORDS (CHACHA_BLOCK_SIZE / sizeof(u32))
+
+struct chacha20_state {
+ struct chacha20_block block;
+};
+
+/*
+ * Have a static memory blocks for the ChaCha20 DRNG instance to avoid calling
+ * kmalloc too early in the boot cycle. For subsequent allocation requests,
+ * such as per-NUMA-node DRNG instances, kmalloc will be used.
+ */
+struct chacha20_state chacha20;
+
+/**
+ * Update of the ChaCha20 state by either using an unused buffer part or by
+ * generating one ChaCha20 block which is half of the state of the ChaCha20.
+ * The block is XORed into the key part of the state. This shall ensure
+ * backtracking resistance as well as a proper mix of the ChaCha20 state once
+ * the key is injected.
+ */
+static void lrng_chacha20_update(struct chacha20_state *chacha20_state,
+ u32 *buf, u32 used_words)
+{
+ struct chacha20_block *chacha20 = &chacha20_state->block;
+ u32 i, tmp[CHACHA_BLOCK_WORDS];
+
+ BUILD_BUG_ON(sizeof(struct chacha20_block) != CHACHA_BLOCK_SIZE);
+ BUILD_BUG_ON(CHACHA_BLOCK_SIZE != 2 * CHACHA_KEY_SIZE);
+
+ if (used_words > CHACHA_KEY_SIZE_WORDS) {
+ chacha20_block(&chacha20->constants[0], (u8 *)tmp);
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++)
+ chacha20->key.u[i] ^= le32_to_cpu(tmp[i]);
+ memzero_explicit(tmp, sizeof(tmp));
+ } else {
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++)
+ chacha20->key.u[i] ^= le32_to_cpu(buf[i + used_words]);
+ }
+
+ /* Deterministic increment of nonce as required in RFC 7539 chapter 4 */
+ chacha20->nonce[0]++;
+ if (chacha20->nonce[0] == 0)
+ chacha20->nonce[1]++;
+ if (chacha20->nonce[1] == 0)
+ chacha20->nonce[2]++;
+
+ /* Leave counter untouched as it is start value is undefined in RFC */
+}
+
+/*
+ * Seed the ChaCha20 DRNG by injecting the input data into the key part of
+ * the ChaCha20 state. If the input data is longer than the ChaCha20 key size,
+ * perform a ChaCha20 operation after processing of key size input data.
+ * This operation shall spread out the entropy into the ChaCha20 state before
+ * new entropy is injected into the key part.
+ */
+static int lrng_cc20_drng_seed_helper(void *drng, const u8 *inbuf, u32 inbuflen)
+{
+ struct chacha20_state *chacha20_state = (struct chacha20_state *)drng;
+ struct chacha20_block *chacha20 = &chacha20_state->block;
+
+ while (inbuflen) {
+ u32 i, todo = min_t(u32, inbuflen, CHACHA_KEY_SIZE);
+
+ for (i = 0; i < todo; i++)
+ chacha20->key.b[i] ^= inbuf[i];
+
+ /* Break potential dependencies between the inbuf key blocks */
+ lrng_chacha20_update(chacha20_state, NULL,
+ CHACHA_BLOCK_WORDS);
+ inbuf += todo;
+ inbuflen -= todo;
+ }
+
+ return 0;
+}
+
+/*
+ * Chacha20 DRNG generation of random numbers: the stream output of ChaCha20
+ * is the random number. After the completion of the generation of the
+ * stream, the entire ChaCha20 state is updated.
+ *
+ * Note, as the ChaCha20 implements a 32 bit counter, we must ensure
+ * that this function is only invoked for at most 2^32 - 1 ChaCha20 blocks
+ * before a reseed or an update happens. This is ensured by the variable
+ * outbuflen which is a 32 bit integer defining the number of bytes to be
+ * generated by the ChaCha20 DRNG. At the end of this function, an update
+ * operation is invoked which implies that the 32 bit counter will never be
+ * overflown in this implementation.
+ */
+static int lrng_cc20_drng_generate_helper(void *drng, u8 *outbuf, u32 outbuflen)
+{
+ struct chacha20_state *chacha20_state = (struct chacha20_state *)drng;
+ struct chacha20_block *chacha20 = &chacha20_state->block;
+ u32 aligned_buf[CHACHA_BLOCK_WORDS], ret = outbuflen,
+ used = CHACHA_BLOCK_WORDS;
+ int zeroize_buf = 0;
+
+ while (outbuflen >= CHACHA_BLOCK_SIZE) {
+ chacha20_block(&chacha20->constants[0], outbuf);
+ outbuf += CHACHA_BLOCK_SIZE;
+ outbuflen -= CHACHA_BLOCK_SIZE;
+ }
+
+ if (outbuflen) {
+ chacha20_block(&chacha20->constants[0], (u8 *)aligned_buf);
+ memcpy(outbuf, aligned_buf, outbuflen);
+ used = ((outbuflen + sizeof(aligned_buf[0]) - 1) /
+ sizeof(aligned_buf[0]));
+ zeroize_buf = 1;
+ }
+
+ lrng_chacha20_update(chacha20_state, aligned_buf, used);
+
+ if (zeroize_buf)
+ memzero_explicit(aligned_buf, sizeof(aligned_buf));
+
+ return ret;
+}
+
+void lrng_cc20_init_state(struct chacha20_state *state)
+{
+ struct chacha20_block *chacha20 = &state->block;
+ unsigned long v;
+ u32 i;
+
+ lrng_cc20_init_rfc7539(chacha20);
+
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) {
+ chacha20->key.u[i] ^= jiffies;
+ chacha20->key.u[i] ^= random_get_entropy();
+ if (arch_get_random_seed_long(&v) || arch_get_random_long(&v))
+ chacha20->key.u[i] ^= v;
+ }
+
+ for (i = 0; i < 3; i++) {
+ chacha20->nonce[i] ^= jiffies;
+ chacha20->nonce[i] ^= random_get_entropy();
+ if (arch_get_random_seed_long(&v) || arch_get_random_long(&v))
+ chacha20->nonce[i] ^= v;
+ }
+
+ lrng_chacha20_update(state, NULL, CHACHA_BLOCK_WORDS);
+ pr_info("ChaCha20 core initialized\n");
+}
+
+void __init lrng_cc20_init_state_boot(struct chacha20_state *state)
+{
+ struct chacha20_block *chacha20 = &state->block;
+ unsigned long v;
+ u32 i;
+
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) {
+ if (arch_get_random_seed_long_early(&v) ||
+ arch_get_random_long_early(&v))
+ chacha20->key.u[i] ^= v;
+ }
+
+ for (i = 0; i < 3; i++) {
+ if (arch_get_random_seed_long_early(&v) ||
+ arch_get_random_long_early(&v))
+ chacha20->nonce[i] ^= v;
+ }
+
+ lrng_chacha20_update(state, NULL, CHACHA_BLOCK_WORDS);
+}
+
+/*
+ * Allocation of the DRNG state
+ */
+static void *lrng_cc20_drng_alloc(u32 sec_strength)
+{
+ struct chacha20_state *state = NULL;
+
+ if (sec_strength > CHACHA_KEY_SIZE) {
+ pr_err("Security strength of ChaCha20 DRNG (%u bits) lower than requested by LRNG (%u bits)\n",
+ CHACHA_KEY_SIZE * 8, sec_strength * 8);
+ return ERR_PTR(-EINVAL);
+ }
+ if (sec_strength < CHACHA_KEY_SIZE)
+ pr_warn("Security strength of ChaCha20 DRNG (%u bits) higher than requested by LRNG (%u bits)\n",
+ CHACHA_KEY_SIZE * 8, sec_strength * 8);
+
+ state = kmalloc(sizeof(struct chacha20_state), GFP_KERNEL);
+ if (!state)
+ return ERR_PTR(-ENOMEM);
+ pr_debug("memory for ChaCha20 core allocated\n");
+
+ lrng_cc20_init_state(state);
+
+ return state;
+}
+
+static void lrng_cc20_drng_dealloc(void *drng)
+{
+ struct chacha20_state *chacha20_state = (struct chacha20_state *)drng;
+
+ if (drng == &chacha20) {
+ memzero_explicit(chacha20_state, sizeof(*chacha20_state));
+ pr_debug("static ChaCha20 core zeroized\n");
+ return;
+ }
+
+ pr_debug("ChaCha20 core zeroized and freed\n");
+ kzfree(chacha20_state);
+}
+
+/******************************* Hash Operation *******************************/
+
+#ifdef CONFIG_CRYPTO_LIB_SHA256
+
+static u32 lrng_cc20_hash_digestsize(void *hash)
+{
+ return SHA256_DIGEST_SIZE;
+}
+
+static int lrng_cc20_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest)
+{
+ struct sha256_state sctx;
+
+ sha256_init(&sctx);
+ sha256_update(&sctx, inbuf, inbuflen);
+ sha256_final(&sctx, digest);
+
+ /* Zeroization of sctx is performed by sha256_final */
+
+ return 0;
+}
+
+static const char *lrng_cc20_hash_name(void)
+{
+ const char *cc20_hash_name = "SHA-256";
+ return cc20_hash_name;
+}
+
+#else /* CONFIG_CRYPTO_LIB_SHA256 */
+
+/*
+ * If the SHA-256 support is not compiled, we fall back to SHA-1 that is always
+ * compiled and present in the kernel.
+ */
+static u32 lrng_cc20_hash_digestsize(void *hash)
+{
+ return (SHA1_DIGEST_WORDS * sizeof(u32));
+}
+
+static int lrng_cc20_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest)
+{
+ u32 i;
+ u32 workspace[SHA1_WORKSPACE_WORDS];
+
+ WARN_ON(inbuflen % (SHA1_WORKSPACE_WORDS * sizeof(u32)));
+
+ sha1_init((u32 *)digest);
+ for (i = 0; i < inbuflen; i += (SHA1_WORKSPACE_WORDS * sizeof(u32)))
+ sha1_transform((u32 *)digest, (inbuf + i), workspace);
+ memzero_explicit(workspace, sizeof(workspace));
+
+ return 0;
+}
+
+static const char *lrng_cc20_hash_name(void)
+{
+ const char *cc20_hash_name = "SHA-1";
+ return cc20_hash_name;
+}
+
+#endif /* CONFIG_CRYPTO_LIB_SHA256 */
+
+static void *lrng_cc20_hash_alloc(const u8 *key, u32 keylen)
+{
+ pr_info("Hash %s allocated\n", lrng_cc20_hash_name());
+ return NULL;
+}
+
+static void lrng_cc20_hash_dealloc(void *hash)
+{
+}
+
+static const char *lrng_cc20_drng_name(void)
+{
+ const char *cc20_drng_name = "ChaCha20 DRNG";
+ return cc20_drng_name;
+}
+
+const struct lrng_crypto_cb lrng_cc20_crypto_cb = {
+ .lrng_drng_name = lrng_cc20_drng_name,
+ .lrng_hash_name = lrng_cc20_hash_name,
+ .lrng_drng_alloc = lrng_cc20_drng_alloc,
+ .lrng_drng_dealloc = lrng_cc20_drng_dealloc,
+ .lrng_drng_seed_helper = lrng_cc20_drng_seed_helper,
+ .lrng_drng_generate_helper = lrng_cc20_drng_generate_helper,
+ .lrng_hash_alloc = lrng_cc20_hash_alloc,
+ .lrng_hash_dealloc = lrng_cc20_hash_dealloc,
+ .lrng_hash_digestsize = lrng_cc20_hash_digestsize,
+ .lrng_hash_buffer = lrng_cc20_hash_buffer,
+};
diff --git a/drivers/char/lrng/lrng_chacha20.h b/drivers/char/lrng/lrng_chacha20.h
new file mode 100644
index 000000000000..1533b2490964
--- /dev/null
+++ b/drivers/char/lrng/lrng_chacha20.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * LRNG ChaCha20 definitions
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#include <crypto/chacha.h>
+
+/* State according to RFC 7539 section 2.3 */
+struct chacha20_block {
+ u32 constants[4];
+ union {
+#define CHACHA_KEY_SIZE_WORDS (CHACHA_KEY_SIZE / sizeof(u32))
+ u32 u[CHACHA_KEY_SIZE_WORDS];
+ u8 b[CHACHA_KEY_SIZE];
+ } key __latent_entropy;
+ u32 counter;
+ u32 nonce[3] __latent_entropy;
+};
+
+static inline void lrng_cc20_init_rfc7539(struct chacha20_block *chacha20)
+{
+ /* String "expand 32-byte k" */
+ chacha20->constants[0] = 0x61707865;
+ chacha20->constants[1] = 0x3320646e;
+ chacha20->constants[2] = 0x79622d32;
+ chacha20->constants[3] = 0x6b206574;
+}
diff --git a/drivers/char/lrng/lrng_drng.c b/drivers/char/lrng/lrng_drng.c
new file mode 100644
index 000000000000..ac6e40794cfe
--- /dev/null
+++ b/drivers/char/lrng/lrng_drng.c
@@ -0,0 +1,409 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG DRNG processing
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/lrng.h>
+
+#include "lrng_internal.h"
+
+/*
+ * Maximum number of seconds between DRNG reseed intervals of the DRNG. Note,
+ * this is enforced with the next request of random numbers from the
+ * DRNG. Setting this value to zero implies a reseeding attempt before every
+ * generated random number.
+ */
+int lrng_drng_reseed_max_time = 600;
+
+static atomic_t lrng_avail = ATOMIC_INIT(0);
+
+DEFINE_MUTEX(lrng_crypto_cb_update);
+
+/* DRNG for /dev/urandom, getrandom(2), get_random_bytes */
+static struct lrng_drng lrng_drng_init = {
+ .drng = &chacha20,
+ .crypto_cb = &lrng_cc20_crypto_cb,
+ .lock = __MUTEX_INITIALIZER(lrng_drng_init.lock),
+ .spin_lock = __SPIN_LOCK_UNLOCKED(lrng_drng_init.spin_lock)
+};
+
+/*
+ * DRNG for get_random_bytes when called in atomic context. This
+ * DRNG will always use the ChaCha20 DRNG. It will never benefit from a
+ * DRNG switch like the "regular" DRNG. If there was no DRNG switch, the atomic
+ * DRNG is identical to the "regular" DRNG.
+ *
+ * The reason for having this is due to the fact that DRNGs other than
+ * the ChaCha20 DRNG may sleep.
+ */
+static struct lrng_drng lrng_drng_atomic = {
+ .drng = &chacha20,
+ .crypto_cb = &lrng_cc20_crypto_cb,
+ .spin_lock = __SPIN_LOCK_UNLOCKED(lrng_drng_atomic.spin_lock)
+};
+
+/********************************** Helper ************************************/
+
+bool lrng_get_available(void)
+{
+ return likely(atomic_read(&lrng_avail));
+}
+
+void lrng_set_available(void)
+{
+ atomic_set(&lrng_avail, 1);
+}
+
+struct lrng_drng *lrng_drng_init_instance(void)
+{
+ return &lrng_drng_init;
+}
+
+struct lrng_drng *lrng_drng_atomic_instance(void)
+{
+ return &lrng_drng_atomic;
+}
+
+void lrng_drng_reset(struct lrng_drng *drng)
+{
+ atomic_set(&drng->requests, LRNG_DRNG_RESEED_THRESH);
+ drng->last_seeded = jiffies;
+ drng->fully_seeded = false;
+ drng->force_reseed = true;
+ pr_debug("reset DRNG\n");
+}
+
+/* Initialize the default DRNG during boot */
+static void lrng_drngs_init_cc20(void)
+{
+ unsigned long flags = 0;
+
+ if (lrng_get_available())
+ return;
+
+ lrng_drng_lock(&lrng_drng_init, &flags);
+ if (lrng_get_available()) {
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+ return;
+ }
+
+ lrng_drng_reset(&lrng_drng_init);
+ lrng_cc20_init_state(&chacha20);
+ lrng_state_init_seed_work();
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+
+ lrng_drng_lock(&lrng_drng_atomic, &flags);
+ lrng_drng_reset(&lrng_drng_atomic);
+ /*
+ * We do not initialize the state of the atomic DRNG as it is identical
+ * to the DRNG at this point.
+ */
+ lrng_drng_unlock(&lrng_drng_atomic, &flags);
+
+ lrng_set_available();
+}
+
+/************************* Random Number Generation ***************************/
+
+/* Inject a data buffer into the DRNG */
+static void lrng_drng_inject(struct lrng_drng *drng,
+ const u8 *inbuf, u32 inbuflen)
+{
+ const char *drng_type = unlikely(drng == &lrng_drng_atomic) ?
+ "atomic" : "regular";
+ unsigned long flags = 0;
+
+ BUILD_BUG_ON(LRNG_DRNG_RESEED_THRESH > INT_MAX);
+ pr_debug("seeding %s DRNG with %u bytes\n", drng_type, inbuflen);
+ lrng_drng_lock(drng, &flags);
+ if (drng->crypto_cb->lrng_drng_seed_helper(drng->drng,
+ inbuf, inbuflen) < 0) {
+ pr_warn("seeding of %s DRNG failed\n", drng_type);
+ atomic_set(&drng->requests, 1);
+ } else {
+ pr_debug("%s DRNG stats since last seeding: %lu secs; generate calls: %d\n",
+ drng_type,
+ (time_after(jiffies, drng->last_seeded) ?
+ (jiffies - drng->last_seeded) : 0) / HZ,
+ (LRNG_DRNG_RESEED_THRESH -
+ atomic_read(&drng->requests)));
+ drng->last_seeded = jiffies;
+ atomic_set(&drng->requests, LRNG_DRNG_RESEED_THRESH);
+ drng->force_reseed = false;
+
+ if (drng->drng == lrng_drng_atomic.drng) {
+ lrng_drng_atomic.last_seeded = jiffies;
+ atomic_set(&lrng_drng_atomic.requests,
+ LRNG_DRNG_RESEED_THRESH);
+ lrng_drng_atomic.force_reseed = false;
+ }
+ }
+ lrng_drng_unlock(drng, &flags);
+}
+
+/*
+ * Perform the seeding of the DRNG with data from noise source
+ */
+static inline int _lrng_drng_seed(struct lrng_drng *drng)
+{
+ struct entropy_buf seedbuf __aligned(LRNG_KCAPI_ALIGN);
+ unsigned long flags = 0;
+ u32 total_entropy_bits;
+ int ret;
+
+ lrng_drng_lock(drng, &flags);
+ total_entropy_bits = lrng_fill_seed_buffer(drng->crypto_cb, drng->hash,
+ &seedbuf, 0);
+ lrng_drng_unlock(drng, &flags);
+
+ /* Allow the seeding operation to be called again */
+ lrng_pool_unlock();
+ lrng_init_ops(total_entropy_bits);
+ ret = total_entropy_bits >> 3;
+
+ lrng_drng_inject(drng, (u8 *)&seedbuf, sizeof(seedbuf));
+ memzero_explicit(&seedbuf, sizeof(seedbuf));
+
+ return ret;
+}
+
+static int lrng_drng_get(struct lrng_drng *drng, u8 *outbuf, u32 outbuflen);
+static void lrng_drng_seed(struct lrng_drng *drng)
+{
+ int ret = _lrng_drng_seed(drng);
+
+ if (ret >= LRNG_DRNG_SECURITY_STRENGTH_BYTES)
+ drng->fully_seeded = true;
+
+ BUILD_BUG_ON(LRNG_MIN_SEED_ENTROPY_BITS >
+ LRNG_DRNG_SECURITY_STRENGTH_BITS);
+
+ /*
+ * Reseed atomic DRNG from current DRNG,
+ *
+ * We can obtain random numbers from DRNG as the lock type
+ * chosen by lrng_drng_get is usable with the current caller.
+ */
+ if ((drng->drng != lrng_drng_atomic.drng) &&
+ (lrng_drng_atomic.force_reseed ||
+ atomic_read(&lrng_drng_atomic.requests) <= 0 ||
+ time_after(jiffies, lrng_drng_atomic.last_seeded +
+ lrng_drng_reseed_max_time * HZ))) {
+ u8 seedbuf[LRNG_DRNG_SECURITY_STRENGTH_BYTES]
+ __aligned(LRNG_KCAPI_ALIGN);
+
+ ret = lrng_drng_get(drng, seedbuf, sizeof(seedbuf));
+
+ if (ret < 0) {
+ pr_warn("Error generating random numbers for atomic DRNG: %d\n",
+ ret);
+ } else {
+ lrng_drng_inject(&lrng_drng_atomic, seedbuf, ret);
+ }
+ memzero_explicit(&seedbuf, sizeof(seedbuf));
+ }
+}
+
+static inline void _lrng_drng_seed_work(struct lrng_drng *drng, u32 node)
+{
+ pr_debug("reseed triggered by interrupt noise source for DRNG on NUMA node %d\n",
+ node);
+ lrng_drng_seed(drng);
+ if (drng->fully_seeded) {
+ /* Prevent reseed storm */
+ drng->last_seeded += node * 100 * HZ;
+ /* Prevent draining of pool on idle systems */
+ lrng_drng_reseed_max_time += 100;
+ }
+}
+
+/*
+ * DRNG reseed trigger: Kernel thread handler triggered by the schedule_work()
+ */
+void lrng_drng_seed_work(struct work_struct *dummy)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ u32 node;
+
+ if (lrng_drng) {
+ for_each_online_node(node) {
+ struct lrng_drng *drng = lrng_drng[node];
+
+ if (drng && !drng->fully_seeded) {
+ _lrng_drng_seed_work(drng, node);
+ goto out;
+ }
+ }
+ lrng_pool_all_numa_nodes_seeded();
+ } else {
+ if (!lrng_drng_init.fully_seeded)
+ _lrng_drng_seed_work(&lrng_drng_init, 0);
+ }
+
+out:
+ /* Allow the seeding operation to be called again */
+ lrng_pool_unlock();
+}
+
+/* Force all DRNGs to reseed before next generation */
+void lrng_drng_force_reseed(void)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ u32 node;
+
+ if (!lrng_drng) {
+ lrng_drng_init.force_reseed = true;
+ pr_debug("force reseed of initial DRNG\n");
+ return;
+ }
+ for_each_online_node(node) {
+ struct lrng_drng *drng = lrng_drng[node];
+
+ if (!drng)
+ continue;
+
+ drng->force_reseed = true;
+ pr_debug("force reseed of DRNG on node %u\n", node);
+ }
+ lrng_drng_atomic.force_reseed = true;
+}
+
+/**
+ * lrng_drng_get() - Get random data out of the DRNG which is reseeded
+ * frequently.
+ *
+ * @outbuf: buffer for storing random data
+ * @outbuflen: length of outbuf
+ *
+ * Return:
+ * * < 0 in error case (DRNG generation or update failed)
+ * * >=0 returning the returned number of bytes
+ */
+static int lrng_drng_get(struct lrng_drng *drng, u8 *outbuf, u32 outbuflen)
+{
+ unsigned long flags = 0;
+ u32 processed = 0;
+
+ if (!outbuf || !outbuflen)
+ return 0;
+
+ outbuflen = min_t(size_t, outbuflen, INT_MAX);
+
+ lrng_drngs_init_cc20();
+
+ while (outbuflen) {
+ u32 todo = min_t(u32, outbuflen, LRNG_DRNG_MAX_REQSIZE);
+ int ret;
+
+ /* All but the atomic DRNG are seeded during generation */
+ if (atomic_dec_and_test(&drng->requests) ||
+ drng->force_reseed ||
+ time_after(jiffies, drng->last_seeded +
+ lrng_drng_reseed_max_time * HZ)) {
+ if (likely(drng != &lrng_drng_atomic)) {
+ if (lrng_pool_trylock())
+ atomic_set(&drng->requests, 1);
+ else
+ lrng_drng_seed(drng);
+ }
+ }
+
+ lrng_drng_lock(drng, &flags);
+ ret = drng->crypto_cb->lrng_drng_generate_helper(
+ drng->drng, outbuf + processed, todo);
+ lrng_drng_unlock(drng, &flags);
+ if (ret <= 0) {
+ pr_warn("getting random data from DRNG failed (%d)\n",
+ ret);
+ return -EFAULT;
+ }
+ processed += ret;
+ outbuflen -= ret;
+ }
+
+ return processed;
+}
+
+int lrng_drng_get_atomic(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_drng_get(&lrng_drng_atomic, outbuf, outbuflen);
+}
+
+int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ struct lrng_drng *drng = &lrng_drng_init;
+ int node = numa_node_id();
+
+ might_sleep();
+
+ if (lrng_drng && lrng_drng[node] && lrng_drng[node]->fully_seeded)
+ drng = lrng_drng[node];
+
+ return lrng_drng_get(drng, outbuf, outbuflen);
+}
+
+/* Reset LRNG such that all existing entropy is gone */
+static void _lrng_reset(struct work_struct *work)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ unsigned long flags = 0;
+
+ if (!lrng_drng) {
+ lrng_drng_lock(&lrng_drng_init, &flags);
+ lrng_drng_reset(&lrng_drng_init);
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+ } else {
+ u32 node;
+
+ for_each_online_node(node) {
+ struct lrng_drng *drng = lrng_drng[node];
+
+ if (!drng)
+ continue;
+ lrng_drng_lock(drng, &flags);
+ lrng_drng_reset(drng);
+ lrng_drng_unlock(drng, &flags);
+ }
+ }
+ lrng_set_entropy_thresh(LRNG_INIT_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS);
+
+ lrng_reset_state();
+}
+
+static DECLARE_WORK(lrng_reset_work, _lrng_reset);
+
+void lrng_reset(void)
+{
+ schedule_work(&lrng_reset_work);
+}
+
+/***************************** Initialize LRNG *******************************/
+
+void __init lrng_drng_init_early(void)
+{
+ unsigned long flags = 0;
+
+ lrng_drng_lock(&lrng_drng_init, &flags);
+ lrng_cc20_init_state_boot(&chacha20);
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+}
+
+static int __init lrng_init(void)
+{
+ lrng_drngs_init_cc20();
+
+ lrng_drngs_numa_alloc();
+ return 0;
+}
+
+late_initcall(lrng_init);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Stephan Mueller <[email protected]>");
+MODULE_DESCRIPTION("Linux Random Number Generator");
diff --git a/drivers/char/lrng/lrng_interfaces.c b/drivers/char/lrng/lrng_interfaces.c
new file mode 100644
index 000000000000..7fc04e54d834
--- /dev/null
+++ b/drivers/char/lrng/lrng_interfaces.c
@@ -0,0 +1,648 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG User and kernel space interfaces
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/freezer.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/kthread.h>
+#include <linux/poll.h>
+#include <linux/preempt.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/timex.h>
+
+#include "lrng_internal.h"
+
+/*
+ * If the entropy count falls under this number of bits, then we
+ * should wake up processes which are selecting or polling on write
+ * access to /dev/random.
+ */
+u32 lrng_write_wakeup_bits = LRNG_WRITE_WAKEUP_ENTROPY;
+
+static LIST_HEAD(lrng_ready_list);
+static DEFINE_SPINLOCK(lrng_ready_list_lock);
+
+static DECLARE_WAIT_QUEUE_HEAD(lrng_write_wait);
+static DECLARE_WAIT_QUEUE_HEAD(lrng_init_wait);
+static struct fasync_struct *fasync;
+
+struct ctl_table random_table[];
+/********************************** Helper ***********************************/
+
+/* Is the DRNG seed level too low? */
+static inline bool lrng_need_entropy(void)
+{
+ return (lrng_avail_entropy() < lrng_write_wakeup_bits);
+}
+
+void lrng_writer_wakeup(void)
+{
+ if (lrng_need_entropy() && wq_has_sleeper(&lrng_write_wait)) {
+ wake_up_interruptible(&lrng_write_wait);
+ kill_fasync(&fasync, SIGIO, POLL_OUT);
+ }
+}
+
+void lrng_init_wakeup(void)
+{
+ wake_up_all(&lrng_init_wait);
+ kill_fasync(&fasync, SIGIO, POLL_IN);
+}
+
+/**
+ * lrng_process_ready_list() - Ping all kernel internal callers waiting until
+ * the DRNG is at least minimally seeded to inform that the DRNG reached that
+ * seed level.
+ *
+ * When the SP800-90B testing is enabled, the ping only happens if the SP800-90B
+ * startup health tests are completed. This implies that kernel internal
+ * callers always have an SP800-90B compliant noise source when being
+ * pinged.
+ */
+void lrng_process_ready_list(void)
+{
+ unsigned long flags;
+ struct random_ready_callback *rdy, *tmp;
+
+ if (!lrng_sp80090b_startup_complete())
+ return;
+
+ spin_lock_irqsave(&lrng_ready_list_lock, flags);
+ list_for_each_entry_safe(rdy, tmp, &lrng_ready_list, list) {
+ struct module *owner = rdy->owner;
+
+ list_del_init(&rdy->list);
+ rdy->func(rdy);
+ module_put(owner);
+ }
+ spin_unlock_irqrestore(&lrng_ready_list_lock, flags);
+}
+
+void lrng_debug_report_seedlevel(const char *name)
+{
+#ifdef CONFIG_WARN_ALL_UNSEEDED_RANDOM
+ static void *previous = NULL;
+ void *caller = (void *) _RET_IP_;
+
+ if (READ_ONCE(previous) == caller)
+ return;
+
+ if (!lrng_state_min_seeded())
+ pr_notice("%pS %s called without reaching mimimally seeded level (available entropy %u)\n",
+ caller, name, lrng_avail_entropy());
+
+ WRITE_ONCE(previous, caller);
+#endif
+}
+
+/************************ LRNG kernel input interfaces ************************/
+
+/**
+ * add_hwgenerator_randomness() - Interface for in-kernel drivers of true
+ * hardware RNGs.
+ *
+ * Those devices may produce endless random bits and will be throttled
+ * when our pool is full.
+ *
+ * @buffer: buffer holding the entropic data from HW noise sources to be used to
+ * insert into entropy pool.
+ * @count: length of buffer
+ * @entropy_bits: amount of entropy in buffer (value is in bits)
+ */
+void add_hwgenerator_randomness(const char *buffer, size_t count,
+ size_t entropy_bits)
+{
+ /*
+ * Suspend writing if we are fully loaded with entropy.
+ * We'll be woken up again once below lrng_write_wakeup_thresh,
+ * or when the calling thread is about to terminate.
+ */
+ wait_event_interruptible(lrng_write_wait,
+ lrng_need_entropy() ||
+ lrng_state_exseed_allow(lrng_noise_source_hw) ||
+ kthread_should_stop());
+ lrng_state_exseed_set(lrng_noise_source_hw, false);
+ lrng_pool_lfsr_nonaligned(buffer, count);
+ lrng_pool_add_entropy(entropy_bits);
+}
+EXPORT_SYMBOL_GPL(add_hwgenerator_randomness);
+
+/**
+ * add_bootloader_randomness() - Handle random seed passed by bootloader.
+ *
+ * If the seed is trustworthy, it would be regarded as hardware RNGs. Otherwise
+ * it would be regarded as device data.
+ * The decision is controlled by CONFIG_RANDOM_TRUST_BOOTLOADER.
+ *
+ * @buf: buffer holding the entropic data from HW noise sources to be used to
+ * insert into entropy pool.
+ * @size: length of buffer
+ */
+void add_bootloader_randomness(const void *buf, unsigned int size)
+{
+ if (IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER))
+ add_hwgenerator_randomness(buf, size, size * 8);
+ else
+ add_device_randomness(buf, size);
+}
+EXPORT_SYMBOL_GPL(add_bootloader_randomness);
+
+/*
+ * Callback for HID layer -- use the HID event values to stir the entropy pool
+ */
+void add_input_randomness(unsigned int type, unsigned int code,
+ unsigned int value)
+{
+ static unsigned char last_value;
+
+ /* ignore autorepeat and the like */
+ if (value == last_value)
+ return;
+
+ last_value = value;
+
+ lrng_pool_lfsr_u32((type << 4) ^ code ^ (code >> 4) ^ value);
+}
+EXPORT_SYMBOL_GPL(add_input_randomness);
+
+/**
+ * add_device_randomness() - Add device- or boot-specific data to the entropy
+ * pool to help initialize it.
+ *
+ * None of this adds any entropy; it is meant to avoid the problem of
+ * the entropy pool having similar initial state across largely
+ * identical devices.
+ *
+ * @buf: buffer holding the entropic data from HW noise sources to be used to
+ * insert into entropy pool.
+ * @size: length of buffer
+ */
+void add_device_randomness(const void *buf, unsigned int size)
+{
+ lrng_pool_lfsr_nonaligned((u8 *)buf, size);
+ lrng_pool_lfsr_u32(random_get_entropy());
+ lrng_pool_lfsr_u32(jiffies);
+}
+EXPORT_SYMBOL(add_device_randomness);
+
+#ifdef CONFIG_BLOCK
+void rand_initialize_disk(struct gendisk *disk) { }
+void add_disk_randomness(struct gendisk *disk) { }
+EXPORT_SYMBOL(add_disk_randomness);
+#endif
+
+/**
+ * del_random_ready_callback() - Delete a previously registered readiness
+ * callback function.
+ *
+ * @rdy: callback definition that was registered initially
+ */
+void del_random_ready_callback(struct random_ready_callback *rdy)
+{
+ unsigned long flags;
+ struct module *owner = NULL;
+
+ spin_lock_irqsave(&lrng_ready_list_lock, flags);
+ if (!list_empty(&rdy->list)) {
+ list_del_init(&rdy->list);
+ owner = rdy->owner;
+ }
+ spin_unlock_irqrestore(&lrng_ready_list_lock, flags);
+
+ module_put(owner);
+}
+EXPORT_SYMBOL(del_random_ready_callback);
+
+/**
+ * add_random_ready_callback() - Add a callback function that will be invoked
+ * when the DRNG is mimimally seeded.
+ *
+ * @rdy: callback definition to be invoked when the LRNG is seeded
+ *
+ * Return:
+ * * 0 if callback is successfully added
+ * * -EALREADY if pool is already initialised (callback not called)
+ * * -ENOENT if module for callback is not alive
+ */
+int add_random_ready_callback(struct random_ready_callback *rdy)
+{
+ struct module *owner;
+ unsigned long flags;
+ int err = -EALREADY;
+
+ if (likely(lrng_state_min_seeded()))
+ return err;
+
+ owner = rdy->owner;
+ if (!try_module_get(owner))
+ return -ENOENT;
+
+ spin_lock_irqsave(&lrng_ready_list_lock, flags);
+ if (lrng_state_min_seeded())
+ goto out;
+
+ owner = NULL;
+
+ list_add(&rdy->list, &lrng_ready_list);
+ err = 0;
+
+out:
+ spin_unlock_irqrestore(&lrng_ready_list_lock, flags);
+
+ module_put(owner);
+
+ return err;
+}
+EXPORT_SYMBOL(add_random_ready_callback);
+
+/*********************** LRNG kernel output interfaces ************************/
+
+/**
+ * get_random_bytes() - Provider of cryptographic strong random numbers for
+ * kernel-internal usage.
+ *
+ * This function is appropriate for all in-kernel use cases. However,
+ * it will always use the ChaCha20 DRNG.
+ *
+ * @buf: buffer to store the random bytes
+ * @nbytes: size of the buffer
+ */
+void get_random_bytes(void *buf, int nbytes)
+{
+ lrng_drng_get_atomic((u8 *)buf, (u32)nbytes);
+ lrng_debug_report_seedlevel("get_random_bytes");
+}
+EXPORT_SYMBOL(get_random_bytes);
+
+/**
+ * get_random_bytes_full() - Provider of cryptographic strong random numbers
+ * for kernel-internal usage.
+ *
+ * This function is appropriate only for non-atomic use cases as this
+ * function may sleep. Though, it provides access to the full functionality
+ * of LRNG including the switchable DRNG support, that may support other
+ * DRNGs such as the SP800-90A DRBG.
+ *
+ * @buf: buffer to store the random bytes
+ * @nbytes: size of the buffer
+ */
+void get_random_bytes_full(void *buf, int nbytes)
+{
+ lrng_drng_get_sleep((u8 *)buf, (u32)nbytes);
+ lrng_debug_report_seedlevel("get_random_bytes_full");
+}
+EXPORT_SYMBOL(get_random_bytes_full);
+
+/**
+ * wait_for_random_bytes() - Wait for the LRNG to be seeded and thus
+ * guaranteed to supply cryptographically secure random numbers.
+ *
+ * This applies to: the /dev/urandom device, the get_random_bytes function,
+ * and the get_random_{u32,u64,int,long} family of functions. Using any of
+ * these functions without first calling this function forfeits the guarantee
+ * of security.
+ *
+ * Return:
+ * * 0 if the LRNG has been seeded.
+ * * -ERESTARTSYS if the function was interrupted by a signal.
+ */
+int wait_for_random_bytes(void)
+{
+ if (likely(lrng_state_min_seeded()))
+ return 0;
+ return wait_event_interruptible(lrng_init_wait,
+ lrng_state_min_seeded());
+}
+EXPORT_SYMBOL(wait_for_random_bytes);
+
+/**
+ * get_random_bytes_arch() - This function will use the architecture-specific
+ * hardware random number generator if it is available.
+ *
+ * The arch-specific hw RNG will almost certainly be faster than what we can
+ * do in software, but it is impossible to verify that it is implemented
+ * securely (as opposed, to, say, the AES encryption of a sequence number using
+ * a key known by the NSA). So it's useful if we need the speed, but only if
+ * we're willing to trust the hardware manufacturer not to have put in a back
+ * door.
+ *
+ * @buf: buffer allocated by caller to store the random data in
+ * @nbytes: length of outbuf
+ *
+ * Return: number of bytes filled in.
+ */
+int __must_check get_random_bytes_arch(void *buf, int nbytes)
+{
+ u8 *p = buf;
+
+ while (nbytes) {
+ unsigned long v;
+ int chunk = min_t(int, nbytes, sizeof(unsigned long));
+
+ if (!arch_get_random_long(&v))
+ break;
+
+ memcpy(p, &v, chunk);
+ p += chunk;
+ nbytes -= chunk;
+ }
+
+ if (nbytes)
+ lrng_drng_get_atomic((u8 *)p, (u32)nbytes);
+
+ return nbytes;
+}
+EXPORT_SYMBOL(get_random_bytes_arch);
+
+/*
+ * Returns whether or not the LRNG has been seeded.
+ *
+ * Returns: true if the urandom pool has been seeded.
+ * false if the urandom pool has not been seeded.
+ */
+bool rng_is_initialized(void)
+{
+ return lrng_state_operational();
+}
+EXPORT_SYMBOL(rng_is_initialized);
+
+/************************ LRNG user output interfaces *************************/
+
+static ssize_t lrng_read_common(char __user *buf, size_t nbytes)
+{
+ ssize_t ret = 0;
+ u8 tmpbuf[LRNG_DRNG_BLOCKSIZE] __aligned(LRNG_KCAPI_ALIGN);
+ u8 *tmp_large = NULL, *tmp = tmpbuf;
+ u32 tmplen = sizeof(tmpbuf);
+
+ if (nbytes == 0)
+ return 0;
+
+ /*
+ * Satisfy large read requests -- as the common case are smaller
+ * request sizes, such as 16 or 32 bytes, avoid a kmalloc overhead for
+ * those by using the stack variable of tmpbuf.
+ */
+ if (!CONFIG_BASE_SMALL && (nbytes > sizeof(tmpbuf))) {
+ tmplen = min_t(u32, nbytes, LRNG_DRNG_MAX_REQSIZE);
+ tmp_large = kmalloc(tmplen + LRNG_KCAPI_ALIGN, GFP_KERNEL);
+ if (!tmp_large)
+ tmplen = sizeof(tmpbuf);
+ else
+ tmp = PTR_ALIGN(tmp_large, LRNG_KCAPI_ALIGN);
+ }
+
+ while (nbytes) {
+ u32 todo = min_t(u32, nbytes, tmplen);
+ int rc = 0;
+
+ /* Reschedule if we received a large request. */
+ if ((tmp_large) && need_resched()) {
+ if (signal_pending(current)) {
+ if (ret == 0)
+ ret = -ERESTARTSYS;
+ break;
+ }
+ schedule();
+ }
+
+ rc = lrng_drng_get_sleep(tmp, todo);
+ if (rc <= 0) {
+ if (rc < 0)
+ ret = rc;
+ break;
+ }
+ if (copy_to_user(buf, tmp, rc)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ nbytes -= rc;
+ buf += rc;
+ ret += rc;
+ }
+
+ /* Wipe data just returned from memory */
+ if (tmp_large)
+ kzfree(tmp_large);
+ else
+ memzero_explicit(tmpbuf, sizeof(tmpbuf));
+
+ return ret;
+}
+
+static ssize_t
+lrng_read_common_block(int nonblock, char __user *buf, size_t nbytes)
+{
+ if (nbytes == 0)
+ return 0;
+
+ if (unlikely(!lrng_state_operational())) {
+ int ret;
+
+ if (nonblock)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(lrng_init_wait,
+ lrng_state_operational());
+ if (unlikely(ret))
+ return ret;
+ }
+
+ return lrng_read_common(buf, nbytes);
+}
+
+static ssize_t lrng_drng_read_block(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ return lrng_read_common_block(file->f_flags & O_NONBLOCK, buf, nbytes);
+}
+
+static unsigned int lrng_random_poll(struct file *file, poll_table *wait)
+{
+ __poll_t mask;
+
+ poll_wait(file, &lrng_init_wait, wait);
+ poll_wait(file, &lrng_write_wait, wait);
+ mask = 0;
+ if (lrng_state_operational())
+ mask |= EPOLLIN | EPOLLRDNORM;
+ if (lrng_need_entropy() ||
+ lrng_state_exseed_allow(lrng_noise_source_user))
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ return mask;
+}
+
+static ssize_t lrng_drng_write_common(const char __user *buffer, size_t count,
+ u32 entropy_bits)
+{
+ ssize_t ret = 0;
+ u8 buf[64] __aligned(LRNG_KCAPI_ALIGN);
+ const char __user *p = buffer;
+ u32 orig_entropy_bits = entropy_bits;
+
+ if (!lrng_get_available())
+ return -EAGAIN;
+
+ count = min_t(size_t, count, INT_MAX);
+ while (count > 0) {
+ size_t bytes = min_t(size_t, count, sizeof(buf));
+ u32 ent = min_t(u32, bytes<<3, entropy_bits);
+
+ if (copy_from_user(&buf, p, bytes))
+ return -EFAULT;
+ /* Inject data into entropy pool */
+ lrng_pool_lfsr(buf, bytes);
+ lrng_pool_add_entropy(ent);
+
+ count -= bytes;
+ p += bytes;
+ ret += bytes;
+ entropy_bits -= ent;
+
+ cond_resched();
+ }
+
+ /* Force reseed of DRNG during next data request. */
+ if (!orig_entropy_bits)
+ lrng_drng_force_reseed();
+
+ return ret;
+}
+
+static ssize_t lrng_drng_read(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ if (!lrng_state_min_seeded())
+ pr_notice_ratelimited("%s - use of insufficiently seeded DRNG (%zu bytes read)\n",
+ current->comm, nbytes);
+ else if (!lrng_state_operational())
+ pr_debug_ratelimited("%s - use of not fully seeded DRNG (%zu bytes read)\n",
+ current->comm, nbytes);
+
+ return lrng_read_common(buf, nbytes);
+}
+
+static ssize_t lrng_drng_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ return lrng_drng_write_common(buffer, count, 0);
+}
+
+static long lrng_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+ int size, ent_count_bits;
+ int __user *p = (int __user *)arg;
+
+ switch (cmd) {
+ case RNDGETENTCNT:
+ ent_count_bits = lrng_avail_entropy();
+ if (put_user(ent_count_bits, p))
+ return -EFAULT;
+ return 0;
+ case RNDADDTOENTCNT:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ if (get_user(ent_count_bits, p))
+ return -EFAULT;
+ ent_count_bits = (int)lrng_avail_entropy() + ent_count_bits;
+ if (ent_count_bits < 0)
+ ent_count_bits = 0;
+ if (ent_count_bits > LRNG_POOL_SIZE_BITS)
+ ent_count_bits = LRNG_POOL_SIZE_BITS;
+ lrng_pool_set_entropy(ent_count_bits);
+ return 0;
+ case RNDADDENTROPY:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ if (get_user(ent_count_bits, p++))
+ return -EFAULT;
+ if (ent_count_bits < 0)
+ return -EINVAL;
+ if (get_user(size, p++))
+ return -EFAULT;
+ if (size < 0)
+ return -EINVAL;
+ lrng_state_exseed_set(lrng_noise_source_user, false);
+ /* there cannot be more entropy than data */
+ ent_count_bits = min(ent_count_bits, size<<3);
+ return lrng_drng_write_common((const char __user *)p, size,
+ ent_count_bits);
+ case RNDZAPENTCNT:
+ case RNDCLEARPOOL:
+ /* Clear the entropy pool counter. */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ lrng_pool_set_entropy(0);
+ return 0;
+ case RNDRESEEDCRNG:
+ /*
+ * We leave the capability check here since it is present
+ * in the upstream's RNG implementation. Yet, user space
+ * can trigger a reseed as easy as writing into /dev/random
+ * or /dev/urandom where no privilege is needed.
+ */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ /* Force a reseed of all DRNGs */
+ lrng_drng_force_reseed();
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int lrng_fasync(int fd, struct file *filp, int on)
+{
+ return fasync_helper(fd, filp, on, &fasync);
+}
+
+const struct file_operations random_fops = {
+ .read = lrng_drng_read_block,
+ .write = lrng_drng_write,
+ .poll = lrng_random_poll,
+ .unlocked_ioctl = lrng_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .fasync = lrng_fasync,
+ .llseek = noop_llseek,
+};
+
+const struct file_operations urandom_fops = {
+ .read = lrng_drng_read,
+ .write = lrng_drng_write,
+ .unlocked_ioctl = lrng_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .fasync = lrng_fasync,
+ .llseek = noop_llseek,
+};
+
+SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count,
+ unsigned int, flags)
+{
+ if (flags & ~(GRND_NONBLOCK|GRND_RANDOM|GRND_INSECURE))
+ return -EINVAL;
+
+ /*
+ * Requesting insecure and blocking randomness at the same time makes
+ * no sense.
+ */
+ if ((flags &
+ (GRND_INSECURE|GRND_RANDOM)) == (GRND_INSECURE|GRND_RANDOM))
+ return -EINVAL;
+
+ if (count > INT_MAX)
+ count = INT_MAX;
+
+ if (flags & GRND_INSECURE)
+ return lrng_drng_read(NULL, buf, count, NULL);
+
+ return lrng_read_common_block(flags & GRND_NONBLOCK, buf, count);
+}
diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h
new file mode 100644
index 000000000000..f6a5f0d960c1
--- /dev/null
+++ b/drivers/char/lrng/lrng_internal.h
@@ -0,0 +1,333 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * Copyright (C) 2018 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#ifndef _LRNG_INTERNAL_H
+#define _LRNG_INTERNAL_H
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+
+/*************************** General LRNG parameter ***************************/
+
+/* Entropy pool parameter
+ *
+ * The LRNG_POOL_SIZE cannot be smaller than 64 bytes as the SHA-1 operation
+ * in lrng_chacha20.c requires multiples of 64 bytes
+ */
+#define LRNG_POOL_SIZE (16 << CONFIG_LRNG_POOL_SIZE)
+#define LRNG_POOL_WORD_BYTES (4) /* (sizeof(atomic_t)) */
+#define LRNG_POOL_SIZE_BYTES (LRNG_POOL_SIZE * LRNG_POOL_WORD_BYTES)
+#define LRNG_POOL_SIZE_BITS (LRNG_POOL_SIZE_BYTES * 8)
+#define LRNG_POOL_WORD_BITS (LRNG_POOL_WORD_BYTES * 8)
+
+/* Security strength of LRNG -- this must match DRNG security strength */
+#define LRNG_DRNG_SECURITY_STRENGTH_BYTES 32
+#define LRNG_DRNG_SECURITY_STRENGTH_BITS (LRNG_DRNG_SECURITY_STRENGTH_BYTES * 8)
+#define LRNG_DRNG_BLOCKSIZE 64 /* Maximum of DRNG block sizes */
+
+/*
+ * SP800-90A defines a maximum request size of 1<<16 bytes. The given value is
+ * considered a safer margin.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_DRNG_MAX_REQSIZE (1<<12)
+
+/*
+ * SP800-90A defines a maximum number of requests between reseeds of 2^48.
+ * The given value is considered a much safer margin, balancing requests for
+ * frequent reseeds with the need to conserve entropy. This value MUST NOT be
+ * larger than INT_MAX because it is used in an atomic_t.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_DRNG_RESEED_THRESH (1<<20)
+
+/*
+ * Number of interrupts to be recorded to assume that DRNG security strength
+ * bits of entropy are received.
+ * Note: a value below the DRNG security strength should not be defined as this
+ * may imply the DRNG can never be fully seeded in case other noise
+ * sources are unavailable.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_IRQ_ENTROPY_BITS LRNG_DRNG_SECURITY_STRENGTH_BITS
+
+/*
+ * Min required seed entropy is 128 bits covering the minimum entropy
+ * requirement of SP800-131A and the German BSI's TR02102.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_FULL_SEED_ENTROPY_BITS LRNG_DRNG_SECURITY_STRENGTH_BITS
+#define LRNG_MIN_SEED_ENTROPY_BITS 128
+#define LRNG_INIT_ENTROPY_BITS 32
+
+/*
+ * Amount of entropy that is lost with the conditioning functions of LFSR and
+ * hash_df as shown with the entropy analysis compliant to SP800-90B.
+ */
+#define LRNG_CONDITIONING_ENTROPY_LOSS 1
+
+/*
+ * Wakeup value
+ *
+ * This value is allowed to be changed.
+ */
+#if (LRNG_POOL_SIZE_BITS <= (LRNG_DRNG_SECURITY_STRENGTH_BITS * 2))
+# define LRNG_WRITE_WAKEUP_ENTROPY (LRNG_DRNG_SECURITY_STRENGTH_BITS + \
+ LRNG_CONDITIONING_ENTROPY_LOSS)
+#else
+# define LRNG_WRITE_WAKEUP_ENTROPY (LRNG_DRNG_SECURITY_STRENGTH_BITS * 2)
+#endif
+
+/*
+ * Oversampling factor of IRQ events to obtain
+ * LRNG_DRNG_SECURITY_STRENGTH_BYTES. This factor is used when a
+ * high-resolution time stamp is not available. In this case, jiffies and
+ * register contents are used to fill the entropy pool. These noise sources
+ * are much less entropic than the high-resolution timer. The entropy content
+ * is the entropy content assumed with LRNG_IRQ_ENTROPY_BITS divided by
+ * LRNG_IRQ_OVERSAMPLING_FACTOR.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_IRQ_OVERSAMPLING_FACTOR 10
+
+/*
+ * Alignmask which should cover all cipher implementations
+ * WARNING: If this is changed to a value larger than 8, manual
+ * alignment is necessary as older versions of GCC may not be capable
+ * of aligning stack variables at boundaries greater than 8.
+ * In this case, PTR_ALIGN must be used.
+ */
+#define LRNG_KCAPI_ALIGN 8
+
+/************************ Default DRNG implementation *************************/
+
+extern struct chacha20_state chacha20;
+extern const struct lrng_crypto_cb lrng_cc20_crypto_cb;
+void lrng_cc20_init_state(struct chacha20_state *state);
+void lrng_cc20_init_state_boot(struct chacha20_state *state);
+
+/********************************** /proc *************************************/
+
+static inline void lrng_pool_inc_numa_node(void) { }
+
+/****************************** LRNG interfaces *******************************/
+
+extern u32 lrng_write_wakeup_bits;
+extern int lrng_drng_reseed_max_time;
+
+void lrng_writer_wakeup(void);
+void lrng_init_wakeup(void);
+void lrng_debug_report_seedlevel(const char *name);
+void lrng_process_ready_list(void);
+
+/************************** Entropy pool management ***************************/
+
+enum lrng_external_noise_source {
+ lrng_noise_source_hw,
+ lrng_noise_source_user
+};
+
+bool lrng_state_exseed_allow(enum lrng_external_noise_source source);
+void lrng_state_exseed_set(enum lrng_external_noise_source source, bool type);
+void lrng_state_init_seed_work(void);
+u32 lrng_avail_entropy(void);
+void lrng_set_entropy_thresh(u32 new);
+int lrng_pool_trylock(void);
+void lrng_pool_unlock(void);
+void lrng_reset_state(void);
+void lrng_pool_all_numa_nodes_seeded(void);
+bool lrng_state_min_seeded(void);
+bool lrng_state_fully_seeded(void);
+bool lrng_state_operational(void);
+bool lrng_pool_highres_timer(void);
+void lrng_pool_set_entropy(u32 entropy_bits);
+void lrng_pool_lfsr(const u8 *buf, u32 buflen);
+void lrng_pool_lfsr_nonaligned(const u8 *buf, u32 buflen);
+void lrng_pool_lfsr_u32(u32 value);
+void lrng_pool_add_irq(u32 irq_num);
+void lrng_pool_add_entropy(u32 entropy_bits);
+
+struct entropy_buf {
+ u8 a[LRNG_DRNG_SECURITY_STRENGTH_BYTES];
+ u8 b[LRNG_DRNG_SECURITY_STRENGTH_BYTES];
+ u8 c[LRNG_DRNG_SECURITY_STRENGTH_BYTES];
+ u32 now;
+};
+
+int lrng_fill_seed_buffer(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct entropy_buf *entropy_buf, u32 entropy_retain);
+void lrng_init_ops(u32 seed_bits);
+
+/************************** Jitter RNG Noise Source ***************************/
+
+#ifdef CONFIG_LRNG_JENT
+u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen);
+u32 lrng_jent_entropylevel(void);
+#else /* CONFIG_CRYPTO_JITTERENTROPY */
+static inline u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen) {return 0; }
+static inline u32 lrng_jent_entropylevel(void) { return 0; }
+#endif /* CONFIG_CRYPTO_JITTERENTROPY */
+
+/*************************** CPU-based Noise Source ***************************/
+
+u32 lrng_get_arch(u8 *outbuf);
+u32 lrng_slow_noise_req_entropy(u32 required_entropy_bits);
+
+/****************************** DRNG processing *******************************/
+
+/* Secondary DRNG state handle */
+struct lrng_drng {
+ void *drng; /* DRNG handle */
+ void *hash; /* Hash handle */
+ const struct lrng_crypto_cb *crypto_cb; /* Crypto callbacks */
+ atomic_t requests; /* Number of DRNG requests */
+ unsigned long last_seeded; /* Last time it was seeded */
+ bool fully_seeded; /* Is DRNG fully seeded? */
+ bool force_reseed; /* Force a reseed */
+ struct mutex lock;
+ spinlock_t spin_lock;
+};
+
+extern struct mutex lrng_crypto_cb_update;
+
+struct lrng_drng *lrng_drng_init_instance(void);
+struct lrng_drng *lrng_drng_atomic_instance(void);
+
+static __always_inline bool lrng_drng_is_atomic(struct lrng_drng *drng)
+{
+ return (drng->drng == lrng_drng_atomic_instance()->drng);
+}
+
+/* Lock the DRNG */
+static __always_inline void lrng_drng_lock(struct lrng_drng *drng,
+ unsigned long *flags)
+{
+ /* Use spin lock in case the atomic DRNG context is used */
+ if (lrng_drng_is_atomic(drng)) {
+ spin_lock_irqsave(&drng->spin_lock, *flags);
+
+ /*
+ * In case a lock transition happened while we were spinning,
+ * catch this case and use the new lock type.
+ */
+ if (!lrng_drng_is_atomic(drng)) {
+ spin_unlock_irqrestore(&drng->spin_lock, *flags);
+ mutex_lock(&drng->lock);
+ }
+ } else {
+ mutex_lock(&drng->lock);
+ }
+}
+
+/* Unlock the DRNG */
+static __always_inline void lrng_drng_unlock(struct lrng_drng *drng,
+ unsigned long *flags)
+{
+ if (lrng_drng_is_atomic(drng))
+ spin_unlock_irqrestore(&drng->spin_lock, *flags);
+ else
+ mutex_unlock(&drng->lock);
+}
+
+void lrng_drng_init_early(void);
+bool lrng_get_available(void);
+void lrng_set_available(void);
+void lrng_drng_reset(struct lrng_drng *drng);
+int lrng_drng_get_atomic(u8 *outbuf, u32 outbuflen);
+int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen);
+void lrng_drng_force_reseed(void);
+void lrng_drng_seed_work(struct work_struct *dummy);
+
+static inline struct lrng_drng **lrng_drng_instances(void) { return NULL; }
+static inline void lrng_drngs_numa_alloc(void) { return; }
+
+/************************** Health Test linking code **************************/
+
+enum lrng_health_res {
+ lrng_health_pass, /* Health test passes on time stamp */
+ lrng_health_fail_use, /* Time stamp unhealthy, but mix in */
+ lrng_health_fail_drop /* Time stamp unhealthy, drop it */
+};
+
+#ifdef CONFIG_LRNG_HEALTH_TESTS
+bool lrng_sp80090b_startup_complete(void);
+bool lrng_sp80090b_compliant(void);
+
+enum lrng_health_res lrng_health_test(u32 now_time);
+void lrng_health_disable(void);
+
+void lrng_reset(void);
+#else /* CONFIG_LRNG_HEALTH_TESTS */
+static inline bool lrng_sp80090b_startup_complete(void) { return true; }
+static inline bool lrng_sp80090b_compliant(void) { return false; }
+
+static inline enum lrng_health_res
+lrng_health_test(u32 now_time) { return lrng_health_pass; }
+static inline void lrng_health_disable(void) { }
+#endif /* CONFIG_LRNG_HEALTH_TESTS */
+
+/****************************** Helper code ***********************************/
+
+static inline u32 atomic_read_u32(atomic_t *v)
+{
+ return (u32)atomic_read(v);
+}
+
+/*************************** Auxiliary functions ******************************/
+
+void invalidate_batched_entropy(void);
+
+/***************************** Testing code ***********************************/
+
+#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY
+bool lrng_raw_hires_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_HIRES_ENTROPY */
+static inline bool lrng_raw_hires_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_HIRES_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY
+bool lrng_raw_jiffies_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */
+static inline bool lrng_raw_jiffies_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY
+bool lrng_raw_irq_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_IRQ_ENTROPY */
+static inline bool lrng_raw_irq_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_IRQ_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY
+bool lrng_raw_irqflags_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */
+static inline bool lrng_raw_irqflags_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY
+bool lrng_raw_retip_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_RETIP_ENTROPY */
+static inline bool lrng_raw_retip_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_RETIP_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_ARRAY
+bool lrng_raw_array_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_ARRAY */
+static inline bool lrng_raw_array_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_ARRAY */
+
+#ifdef CONFIG_LRNG_IRQ_PERF
+bool lrng_perf_time(u32 start);
+#else /* CONFIG_LRNG_IRQ_PERF */
+static inline bool lrng_perf_time(u32 start) { return false; }
+#endif /*CONFIG_LRNG_IRQ_PERF */
+
+#endif /* _LRNG_INTERNAL_H */
diff --git a/drivers/char/lrng/lrng_lfsr.h b/drivers/char/lrng/lrng_lfsr.h
new file mode 100644
index 000000000000..1b096a58fccc
--- /dev/null
+++ b/drivers/char/lrng/lrng_lfsr.h
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * LRNG Linear Feedback Shift Register
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+/* Status information about IRQ noise source */
+struct lrng_irq_info {
+ atomic_t num_events; /* Number of healthy IRQs since last read */
+ atomic_t num_events_thresh; /* Reseed threshold */
+ atomic_t reseed_in_progress; /* Flag for on executing reseed */
+ bool irq_highres_timer; /* Is high-resolution timer available? */
+ u32 irq_entropy_bits; /* LRNG_IRQ_ENTROPY_BITS? */
+};
+
+/*
+ * This is the entropy pool used by the slow noise source. Its size should
+ * be at least as large as LRNG_DRNG_SECURITY_STRENGTH_BITS.
+ *
+ * The pool array is aligned to 8 bytes to comfort the kernel crypto API cipher
+ * implementations of the hash functions used to read the pool: for some
+ * accelerated implementations, we need an alignment to avoid a realignment
+ * which involves memcpy(). The alignment to 8 bytes should satisfy all crypto
+ * implementations.
+ *
+ * LRNG_POOL_SIZE is allowed to be changed only if the taps of the polynomial
+ * used for the LFSR are changed as well. The size must be in powers of 2 due
+ * to the mask handling in lrng_pool_lfsr_u32 which uses AND instead of modulo.
+ */
+struct lrng_pool {
+ union {
+ struct {
+ /*
+ * hash_df implementation: counter, requested_bits and
+ * pool form a linear buffer that is used in the
+ * hash_df function specified in SP800-90A section
+ * 10.3.1
+ */
+ unsigned char counter;
+ __be32 requested_bits;
+
+ /* Pool */
+ atomic_t pool[LRNG_POOL_SIZE] __latent_entropy;
+ /* Ptr into pool for next IRQ word injection */
+ atomic_t pool_ptr;
+ /* rotate for LFSR */
+ atomic_t input_rotate;
+ /* All NUMA DRNGs seeded? */
+ bool all_online_numa_node_seeded;
+ /* IRQ noise source status info */
+ struct lrng_irq_info irq_info;
+ /* Serialize read of entropy pool */
+ spinlock_t lock;
+ };
+ /*
+ * Static SHA-1 implementation in lrng_cc20_hash_buffer
+ * processes data 64-byte-wise. Hence, ensure proper size
+ * of LRNG entropy pool data structure.
+ */
+ u8 hash_input_buf[LRNG_POOL_SIZE_BYTES + 64];
+ };
+};
+
+/*
+ * Implement a (modified) twisted Generalized Feedback Shift Register. (See M.
+ * Matsumoto & Y. Kurita, 1992. Twisted GFSR generators. ACM Transactions on
+ * Modeling and Computer Simulation 2(3):179-194. Also see M. Matsumoto & Y.
+ * Kurita, 1994. Twisted GFSR generators II. ACM Transactions on Modeling and
+ * Computer Simulation 4:254-266).
+ */
+static u32 const lrng_twist_table[8] = {
+ 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
+ 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
+
+/*
+ * The polynomials for the LFSR are taken from the document "Table of Linear
+ * Feedback Shift Registers" by Roy Ward, Tim Molteno, October 26, 2007.
+ * The first polynomial is from "Primitive Binary Polynomials" by Wayne
+ * Stahnke (1973) and is primitive as well as irreducible.
+ *
+ * Note, the tap values are smaller by one compared to the documentation because
+ * they are used as an index into an array where the index starts by zero.
+ *
+ * All polynomials were also checked to be primitive and irreducible with magma
+ * which ensures that the key property of the LFSR providing a compression
+ * function for entropy is guaranteed.
+ */
+static u32 const lrng_lfsr_polynomial[][4] = {
+ { 15, 13, 12, 10 }, /* 16 words */
+ { 31, 29, 25, 24 }, /* 32 words */
+ { 63, 62, 60, 59 }, /* 64 words */
+ { 127, 28, 26, 1 }, /* 128 words by Stahnke */
+ { 255, 253, 250, 245 }, /* 256 words */
+ { 511, 509, 506, 503 }, /* 512 words */
+ { 1023, 1014, 1001, 1000 }, /* 1024 words */
+ { 2047, 2034, 2033, 2028 }, /* 2048 words */
+ { 4095, 4094, 4080, 4068 }, /* 4096 words */
+};
+
+static inline void _lrng_pool_lfsr_u32(struct lrng_pool *pool, u32 value)
+{
+ /*
+ * Process the LFSR by altering not adjacent words but rather
+ * more spaced apart words. Using a prime number ensures that all words
+ * are processed evenly. As some the LFSR polynomials taps are close
+ * together, processing adjacent words with the LSFR taps may be
+ * inappropriate as the data just mixed-in at these taps may be not
+ * independent from the current data to be mixed in.
+ */
+ u32 ptr = (u32)atomic_add_return_relaxed(67, &pool->pool_ptr) &
+ (LRNG_POOL_SIZE - 1);
+ /*
+ * Add 7 bits of rotation to the pool. At the beginning of the
+ * pool, add an extra 7 bits rotation, so that successive passes
+ * spread the input bits across the pool evenly.
+ *
+ * Note, there is a race between getting ptr and calculating
+ * input_rotate when ptr is obtained on two or more CPUs at the
+ * same time. This race is irrelevant as it may only come into effect
+ * if 3 or more CPUs race at the same time which is very unlikely. If
+ * the race happens, it applies to one event only. As this rolling
+ * supports the LFSR without being strictly needed, we accept this
+ * race.
+ */
+ u32 input_rotate = (u32)atomic_add_return_relaxed((ptr ? 7 : 14),
+ &pool->input_rotate) & 31;
+ u32 word = rol32(value, input_rotate);
+
+ BUILD_BUG_ON(LRNG_POOL_WORD_BYTES != sizeof(pool->pool[0]));
+ BUILD_BUG_ON(LRNG_POOL_SIZE - 1 !=
+ lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][0]);
+ word ^= atomic_read_u32(&pool->pool[ptr]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][0]) &
+ (LRNG_POOL_SIZE - 1)]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][1]) &
+ (LRNG_POOL_SIZE - 1)]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][2]) &
+ (LRNG_POOL_SIZE - 1)]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][3]) &
+ (LRNG_POOL_SIZE - 1)]);
+
+ word = (word >> 3) ^ lrng_twist_table[word & 7];
+ atomic_set(&pool->pool[ptr], word);
+}
+
+u32 __lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct lrng_pool *pool, u8 *outbuf, u32 requested_bits);
diff --git a/drivers/char/lrng/lrng_pool.c b/drivers/char/lrng/lrng_pool.c
new file mode 100644
index 000000000000..0d4111ce7bc2
--- /dev/null
+++ b/drivers/char/lrng/lrng_pool.c
@@ -0,0 +1,589 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Entropy pool management
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <asm/irq_regs.h>
+#include <linux/lrng.h>
+#include <linux/percpu.h>
+#include <linux/random.h>
+#include <linux/utsname.h>
+#include <linux/workqueue.h>
+
+#include "lrng_internal.h"
+#include "lrng_lfsr.h"
+
+struct lrng_state {
+ bool lrng_operational; /* Is DRNG operational? */
+ bool lrng_fully_seeded; /* Is DRNG fully seeded? */
+ bool lrng_min_seeded; /* Is DRNG minimally seeded? */
+
+ /*
+ * To ensure that external entropy providers cannot dominate the
+ * internal noise sources but yet cannot be dominated by internal
+ * noise sources, the following booleans are intended to allow
+ * external to provide seed once when a DRNG reseed occurs. This
+ * triggering of external noise source is performed even when the
+ * entropy pool has sufficient entropy.
+ */
+ bool lrng_seed_hw; /* Allow HW to provide seed */
+ bool lrng_seed_user; /* Allow user space to provide seed */
+
+ struct work_struct lrng_seed_work; /* (re)seed work queue */
+};
+
+static struct lrng_pool lrng_pool __aligned(LRNG_KCAPI_ALIGN) = {
+ .irq_info = {
+ .irq_entropy_bits = LRNG_IRQ_ENTROPY_BITS,
+ .num_events_thresh = ATOMIC_INIT(LRNG_INIT_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS),
+ /* Sample IRQ pointer data at least during boot */
+ .irq_highres_timer = false },
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_pool.lock)
+};
+
+static struct lrng_state lrng_state = { false, false, false, true, true };
+
+/********************************** Helper ***********************************/
+
+/* External entropy provider is allowed to provide seed data */
+bool lrng_state_exseed_allow(enum lrng_external_noise_source source)
+{
+ if (source == lrng_noise_source_hw)
+ return lrng_state.lrng_seed_hw;
+ return lrng_state.lrng_seed_user;
+}
+
+/* Enable / disable external entropy provider to furnish seed */
+void lrng_state_exseed_set(enum lrng_external_noise_source source, bool type)
+{
+ if (source == lrng_noise_source_hw)
+ lrng_state.lrng_seed_hw = type;
+ else
+ lrng_state.lrng_seed_user = type;
+}
+
+static inline void lrng_state_exseed_allow_all(void)
+{
+ lrng_state_exseed_set(lrng_noise_source_hw, true);
+ lrng_state_exseed_set(lrng_noise_source_user, true);
+}
+
+void lrng_state_init_seed_work(void)
+{
+ INIT_WORK(&lrng_state.lrng_seed_work, lrng_drng_seed_work);
+}
+
+static inline u32 lrng_entropy_to_data(u32 entropy_bits)
+{
+ return ((entropy_bits * lrng_pool.irq_info.irq_entropy_bits) /
+ LRNG_DRNG_SECURITY_STRENGTH_BITS);
+}
+
+static inline u32 lrng_data_to_entropy(u32 irqnum)
+{
+ return ((irqnum * LRNG_DRNG_SECURITY_STRENGTH_BITS) /
+ lrng_pool.irq_info.irq_entropy_bits);
+}
+
+u32 lrng_avail_entropy(void)
+{
+ return min_t(u32, LRNG_POOL_SIZE_BITS, lrng_data_to_entropy(
+ atomic_read_u32(&lrng_pool.irq_info.num_events)));
+}
+
+void lrng_set_entropy_thresh(u32 new)
+{
+ atomic_set(&lrng_pool.irq_info.num_events_thresh,
+ lrng_entropy_to_data(new));
+}
+
+/*
+ * Reading of the LRNG pool is only allowed by one caller. The reading is
+ * only performed to (re)seed DRNGs. Thus, if this "lock" is already taken,
+ * the reseeding operation is in progress. The caller is not intended to wait
+ * but continue with its other operation.
+ */
+int lrng_pool_trylock(void)
+{
+ return atomic_cmpxchg(&lrng_pool.irq_info.reseed_in_progress, 0, 1);
+}
+
+void lrng_pool_unlock(void)
+{
+ atomic_set(&lrng_pool.irq_info.reseed_in_progress, 0);
+}
+
+void lrng_reset_state(void)
+{
+ struct lrng_irq_info *irq_info = &lrng_pool.irq_info;
+
+ atomic_set(&irq_info->num_events, 0);
+ lrng_state.lrng_operational = false;
+ lrng_state.lrng_fully_seeded = false;
+ lrng_state.lrng_min_seeded = false;
+ lrng_pool.all_online_numa_node_seeded = false;
+ pr_debug("reset LRNG\n");
+}
+
+void lrng_pool_all_numa_nodes_seeded(void)
+{
+ lrng_pool.all_online_numa_node_seeded = true;
+}
+
+bool lrng_state_min_seeded(void)
+{
+ return lrng_state.lrng_min_seeded;
+}
+
+bool lrng_state_fully_seeded(void)
+{
+ return lrng_state.lrng_fully_seeded;
+}
+
+bool lrng_state_operational(void)
+{
+ return lrng_state.lrng_operational;
+}
+
+bool lrng_pool_highres_timer(void)
+{
+ return lrng_pool.irq_info.irq_highres_timer;
+}
+
+void lrng_pool_set_entropy(u32 entropy_bits)
+{
+ atomic_set(&lrng_pool.irq_info.num_events,
+ lrng_entropy_to_data(entropy_bits));
+}
+
+static void lrng_pool_configure(bool highres_timer, u32 irq_entropy_bits)
+{
+ struct lrng_irq_info *irq_info = &lrng_pool.irq_info;
+
+ irq_info->irq_highres_timer = highres_timer;
+ if (irq_info->irq_entropy_bits != irq_entropy_bits) {
+ irq_info->irq_entropy_bits = irq_entropy_bits;
+ /* Reset the threshold based on new oversampling factor. */
+ lrng_set_entropy_thresh(atomic_read_u32(
+ &irq_info->num_events_thresh));
+ }
+}
+
+static int __init lrng_init_time_source(void)
+{
+ if (random_get_entropy() || random_get_entropy()) {
+ /*
+ * As the highres timer is identified here, previous interrupts
+ * obtained during boot time are treated like a lowres-timer
+ * would have been present.
+ */
+ lrng_pool_configure(true, LRNG_IRQ_ENTROPY_BITS);
+ } else {
+ lrng_health_disable();
+ lrng_pool_configure(false, LRNG_IRQ_ENTROPY_BITS *
+ LRNG_IRQ_OVERSAMPLING_FACTOR);
+ pr_warn("operating without high-resolution timer and applying IRQ oversampling factor %u\n",
+ LRNG_IRQ_OVERSAMPLING_FACTOR);
+ }
+
+ return 0;
+}
+
+core_initcall(lrng_init_time_source);
+
+/* invoke function with buffer aligned to 4 bytes */
+void lrng_pool_lfsr(const u8 *buf, u32 buflen)
+{
+ u32 *p_buf = (u32 *)buf;
+
+ for (; buflen >= 4; buflen -= 4)
+ lrng_pool_lfsr_u32(*p_buf++);
+
+ buf = (u8 *)p_buf;
+ while (buflen--)
+ lrng_pool_lfsr_u32(*buf++);
+}
+
+void lrng_pool_lfsr_nonaligned(const u8 *buf, u32 buflen)
+{
+ while (buflen) {
+ if (!((unsigned long)buf & (sizeof(u32) - 1))) {
+ lrng_pool_lfsr(buf, buflen);
+ return;
+ }
+
+ lrng_pool_lfsr_u32(*buf++);
+ buflen--;
+ }
+}
+
+/**************************** Interrupt processing ****************************/
+
+/*
+ * Hot code path - inject data into entropy pool using LFSR
+ */
+void lrng_pool_lfsr_u32(u32 value)
+{
+ _lrng_pool_lfsr_u32(&lrng_pool, value);
+}
+
+/*
+ * Hot code path - mix data into entropy pool
+ */
+void lrng_pool_add_irq(u32 irq_num)
+{
+ struct lrng_irq_info *irq_info = &lrng_pool.irq_info;
+
+ atomic_add(irq_num, &irq_info->num_events);
+
+ /*
+ * Once all DRNGs are fully seeded, the interrupt noise
+ * sources will not trigger any reseeding any more.
+ */
+ if (likely(lrng_pool.all_online_numa_node_seeded))
+ return;
+
+ /* Only try to reseed if the DRNG is alive. */
+ if (!lrng_get_available())
+ return;
+
+ /* Only trigger the DRNG reseed if we have collected enough IRQs. */
+ if (atomic_read_u32(&lrng_pool.irq_info.num_events) <
+ atomic_read_u32(&lrng_pool.irq_info.num_events_thresh))
+ return;
+
+ /* Ensure that the seeding only occurs once at any given time. */
+ if (lrng_pool_trylock())
+ return;
+
+ /* Seed the DRNG with IRQ noise. */
+ schedule_work(&lrng_state.lrng_seed_work);
+}
+
+void lrng_pool_add_entropy(u32 entropy_bits)
+{
+ lrng_pool_add_irq(lrng_entropy_to_data(entropy_bits));
+}
+
+/*
+ * Generate a hashed output of pool using the SP800-90A section 10.3.1 hash_df
+ * function
+ */
+u32 __lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct lrng_pool *pool, u8 *outbuf, u32 requested_bits)
+{
+ u32 digestsize, requested_bytes = requested_bits >> 3,
+ generated_bytes = 0;
+ u8 digest[64] __aligned(LRNG_KCAPI_ALIGN);
+
+ digestsize = crypto_cb->lrng_hash_digestsize(hash);
+ if (digestsize > sizeof(digest)) {
+ pr_err("Digest buffer too small\n");
+ return 0;
+ }
+
+ pool->counter = 1;
+ pool->requested_bits = cpu_to_be32(requested_bytes << 3);
+
+ while (requested_bytes) {
+ u32 tocopy = min_t(u32, requested_bytes, digestsize);
+
+ /* The counter must not wrap */
+ if (pool->counter == 0)
+ goto out;
+
+ if (crypto_cb->lrng_hash_buffer(hash, (u8 *)pool,
+ LRNG_POOL_SIZE_BYTES + 64,
+ digest))
+ goto out;
+
+ /* Copy the data out to the caller */
+ memcpy(outbuf + generated_bytes, digest, tocopy);
+ requested_bytes -= tocopy;
+ generated_bytes += tocopy;
+ pool->counter++;
+ }
+
+out:
+ /* Mix read data back into pool for backtracking resistance */
+ if (generated_bytes)
+ lrng_pool_lfsr(outbuf, generated_bytes);
+ memzero_explicit(digest, digestsize);
+ return (generated_bytes<<3);
+}
+
+static inline u32 lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb,
+ void *hash, u8 *outbuf, u32 requested_bits)
+{
+ return __lrng_pool_hash_df(crypto_cb, hash, &lrng_pool, outbuf,
+ requested_bits);
+}
+
+/**
+ * lrng_get_pool() - Read the entropy pool out for use.
+ *
+ * This function handles the translation from the number of received interrupts
+ * into an entropy statement. The conversion depends on LRNG_IRQ_ENTROPY_BITS
+ * which defines how many interrupts must be received to obtain 256 bits of
+ * entropy. With this value, the function lrng_data_to_entropy converts a given
+ * data size (received interrupts, requested amount of data, etc.) into an
+ * entropy statement. lrng_entropy_to_data does the reverse.
+ *
+ * Both functions are agnostic about the type of data: when the number of
+ * interrupts is processed by these functions, the resulting entropy value is in
+ * bits as we assume the entropy of interrupts is measured in bits. When data is
+ * processed, the entropy value is in bytes as the data is measured in bytes.
+ *
+ * @outbuf: buffer to store data in with size LRNG_DRNG_SECURITY_STRENGTH_BYTES
+ * @requested_entropy_bits: requested bits of entropy -- the function will
+ * return at least this amount of entropy if available
+ * @entropy_retain: amount of entropy in bits that should be left in the pool
+ *
+ * Return: estimated entropy from the IRQs that was obtained
+ */
+static u32 lrng_get_pool(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ u8 *outbuf, u32 requested_entropy_bits,
+ u32 entropy_retain)
+{
+ struct lrng_pool *pool = &lrng_pool;
+ struct lrng_state *state = &lrng_state;
+ struct lrng_irq_info *irq_info = &pool->irq_info;
+ unsigned long flags;
+
+ u32 irq_num_events_used, irq_num_events, avail_entropy_bits;
+
+ /* This get_pool operation must only be called once at a given time! */
+ spin_lock_irqsave(&pool->lock, flags);
+
+ /* How many unused interrupts are in entropy pool? */
+ irq_num_events = atomic_read_u32(&irq_info->num_events);
+ /* Convert available interrupts into entropy statement */
+ avail_entropy_bits = lrng_data_to_entropy(irq_num_events);
+
+ /* Cap available entropy to pool size */
+ avail_entropy_bits =
+ min_t(u32, avail_entropy_bits, LRNG_POOL_SIZE_BITS);
+
+ /* How much entropy we need to and can we use? */
+ if (unlikely(!state->lrng_fully_seeded)) {
+ /*
+ * During boot time, we read 256 bits data with
+ * avail_entropy_bits entropy. In case our conservative
+ * entropy estimate underestimates the available entropy
+ * we can transport as much available entropy as
+ * possible. The entropy pool does not operate compliant to
+ * the German AIS 21/31 NTG.1 yet.
+ */
+ requested_entropy_bits =
+ LRNG_DRNG_SECURITY_STRENGTH_BITS;
+ } else {
+ /* Provide all entropy above retaining level */
+ if (avail_entropy_bits < entropy_retain) {
+ requested_entropy_bits = 0;
+ goto out;
+ }
+ avail_entropy_bits -= entropy_retain;
+ requested_entropy_bits = min_t(u32, avail_entropy_bits,
+ requested_entropy_bits);
+ }
+
+ /* Hash is a compression function: we generate entropy amount of data */
+ requested_entropy_bits = round_down(requested_entropy_bits, 8);
+
+ requested_entropy_bits = lrng_pool_hash_df(crypto_cb, hash, outbuf,
+ requested_entropy_bits);
+
+ /* Boot time: After getting the full buffer adjust the entropy value. */
+ requested_entropy_bits = min_t(u32, avail_entropy_bits,
+ requested_entropy_bits);
+
+out:
+ /* Convert used entropy into interrupt number for subtraction */
+ irq_num_events_used = lrng_entropy_to_data(requested_entropy_bits);
+
+ /*
+ * The hash_df operation entropy assessment shows that the output
+ * entropy is one bit smaller than the input entropy. Therefore we
+ * account for this one bit of entropy here: if we have sufficient
+ * entropy in the LFSR, we say we used one bit of entropy more.
+ * Otherwise we reduce the amount of entropy we say we generated with
+ * the hash_df.
+ */
+ if (irq_num_events_used) {
+ if ((irq_num_events_used + LRNG_CONDITIONING_ENTROPY_LOSS) <=
+ lrng_entropy_to_data(avail_entropy_bits)) {
+ irq_num_events_used += LRNG_CONDITIONING_ENTROPY_LOSS;
+ } else {
+ if (unlikely(requested_entropy_bits <
+ LRNG_CONDITIONING_ENTROPY_LOSS))
+ requested_entropy_bits = 0;
+ else
+ requested_entropy_bits -=
+ LRNG_CONDITIONING_ENTROPY_LOSS;
+ }
+ }
+
+ /*
+ * New events might have arrived in the meanwhile and we don't
+ * want to throw them away unconditionally. On the other hand,
+ * these new events might have been mixed in before
+ * lrng_hash_df_pool() had been able to draw any entropy
+ * from the pool and thus, the pool capacity might have been
+ * exceeded at some point. Note that in theory, some events
+ * might get lost inbetween the atomic_read() and
+ * atomic_set() below. But that's fine, because it's no real
+ * concern while code preventing this would come at the cost of
+ * additional complexity. Likewise, some events which arrived
+ * after full or partial completion of the __lrng_hash_df_pool()
+ * above might get unnecessarily thrown away by the min()
+ * operation below; the same argument applies there.
+ */
+ irq_num_events = atomic_read_u32(&irq_info->num_events);
+ irq_num_events = min_t(u32, irq_num_events,
+ lrng_entropy_to_data(LRNG_POOL_SIZE_BITS));
+ irq_num_events -= irq_num_events_used;
+ atomic_set(&irq_info->num_events, irq_num_events);
+
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ /* Obtain entropy statement in bits from the used entropy */
+ pr_debug("obtained %u bits of entropy from %u newly collected interrupts - not using %u interrupts\n",
+ requested_entropy_bits, irq_num_events_used,
+ irq_num_events);
+
+ return requested_entropy_bits;
+}
+
+/* Fill the seed buffer with data from the noise sources */
+int lrng_fill_seed_buffer(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct entropy_buf *entropy_buf, u32 entropy_retain)
+{
+ struct lrng_state *state = &lrng_state;
+ u32 total_entropy_bits = 0;
+
+ /* Require at least 128 bits of entropy for any reseed. */
+ if (state->lrng_fully_seeded &&
+ (lrng_avail_entropy() <
+ lrng_slow_noise_req_entropy(LRNG_MIN_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS) +
+ entropy_retain))
+ goto wakeup;
+
+ /*
+ * Concatenate the output of the noise sources. This would be the
+ * spot to add an entropy extractor logic if desired. Note, this
+ * has the ability to collect entropy equal or larger than the DRNG
+ * strength.
+ */
+ total_entropy_bits = lrng_get_pool(crypto_cb, hash, entropy_buf->a,
+ LRNG_DRNG_SECURITY_STRENGTH_BITS,
+ entropy_retain);
+ total_entropy_bits += lrng_get_arch(entropy_buf->b);
+ total_entropy_bits += lrng_get_jent(entropy_buf->c,
+ LRNG_DRNG_SECURITY_STRENGTH_BYTES);
+
+ /* also reseed the DRNG with the current time stamp */
+ entropy_buf->now = random_get_entropy();
+
+ /* allow external entropy provider to provide seed */
+ lrng_state_exseed_allow_all();
+
+wakeup:
+ /*
+ * Shall we wake up user space writers? This location covers
+ * ensures that the user space provider does not dominate the internal
+ * noise sources since in case the first call of this function finds
+ * sufficient entropy in the entropy pool, it will not trigger the
+ * wakeup. This implies that when the next /dev/urandom read happens,
+ * the entropy pool is drained.
+ */
+ lrng_writer_wakeup();
+
+ return total_entropy_bits;
+}
+
+/**
+ * lrng_init_ops() - Set seed stages of LRNG
+ *
+ * Set the slow noise source reseed trigger threshold. The initial threshold
+ * is set to the minimum data size that can be read from the pool: a word. Upon
+ * reaching this value, the next seed threshold of 128 bits is set followed
+ * by 256 bits.
+ *
+ * @entropy_bits: size of entropy currently injected into DRNG
+ */
+void lrng_init_ops(u32 seed_bits)
+{
+ struct lrng_state *state = &lrng_state;
+
+ if (state->lrng_operational)
+ return;
+
+ /* DRNG is seeded with full security strength */
+ if (state->lrng_fully_seeded) {
+ state->lrng_operational = lrng_sp80090b_startup_complete();
+ lrng_process_ready_list();
+ lrng_init_wakeup();
+ } else if (seed_bits >= LRNG_FULL_SEED_ENTROPY_BITS) {
+ invalidate_batched_entropy();
+ state->lrng_fully_seeded = true;
+ state->lrng_operational = lrng_sp80090b_startup_complete();
+ state->lrng_min_seeded = true;
+ pr_info("LRNG fully seeded with %u bits of entropy\n",
+ seed_bits);
+ lrng_set_entropy_thresh(LRNG_FULL_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS);
+ lrng_process_ready_list();
+ lrng_init_wakeup();
+
+ } else if (!state->lrng_min_seeded) {
+
+ /* DRNG is seeded with at least 128 bits of entropy */
+ if (seed_bits >= LRNG_MIN_SEED_ENTROPY_BITS) {
+ invalidate_batched_entropy();
+ state->lrng_min_seeded = true;
+ pr_info("LRNG minimally seeded with %u bits of entropy\n",
+ seed_bits);
+ lrng_set_entropy_thresh(
+ lrng_slow_noise_req_entropy(
+ LRNG_FULL_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS));
+ lrng_process_ready_list();
+ lrng_init_wakeup();
+
+ /* DRNG is seeded with at least LRNG_INIT_ENTROPY_BITS bits */
+ } else if (seed_bits >= LRNG_INIT_ENTROPY_BITS) {
+ pr_info("LRNG initial entropy level %u bits of entropy\n",
+ seed_bits);
+ lrng_set_entropy_thresh(
+ lrng_slow_noise_req_entropy(
+ LRNG_MIN_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS));
+ }
+ }
+}
+
+int __init rand_initialize(void)
+{
+ ktime_t now_time = ktime_get_real();
+ unsigned long rand;
+ unsigned int i;
+
+ lrng_drng_init_early();
+
+ lrng_pool_lfsr_u32(now_time);
+ for (i = 0; i < LRNG_POOL_SIZE; i++) {
+ if (!arch_get_random_seed_long_early(&rand) &&
+ !arch_get_random_long_early(&rand))
+ rand = random_get_entropy();
+ lrng_pool_lfsr((u8 *)&rand, sizeof(rand));
+ }
+ lrng_pool_lfsr_nonaligned((u8 *)utsname(), sizeof(*(utsname())));
+
+ return 0;
+}
diff --git a/drivers/char/lrng/lrng_sw_noise.c b/drivers/char/lrng/lrng_sw_noise.c
new file mode 100644
index 000000000000..b34a82ed9112
--- /dev/null
+++ b/drivers/char/lrng/lrng_sw_noise.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Slow Noise Source: Interrupt data collection
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#include <asm/irq_regs.h>
+#include <asm/ptrace.h>
+#include <linux/random.h>
+
+#include "lrng_internal.h"
+#include "lrng_sw_noise.h"
+
+/* Holder of time stamps before mixing them into the entropy pool */
+static DEFINE_PER_CPU(u32 [LRNG_TIME_ARRAY_SIZE], lrng_time);
+static DEFINE_PER_CPU(u32, lrng_time_ptr) = 0;
+static DEFINE_PER_CPU(u8, lrng_time_irqs) = 0;
+
+/*
+ * Batching up of entropy in per-CPU array before injecting into entropy pool.
+ *
+ * The random32_data is solely to be used for the external random32 PRNG.
+ */
+static inline void lrng_time_process(u32 random32_data)
+{
+ u32 i, ptr, now_time = random_get_entropy();
+ u32 now_time_masked = now_time & LRNG_TIME_SLOTSIZE_MASK;
+ enum lrng_health_res health_test;
+
+ /* Ensure sufficient space in lrng_time_irqs */
+ BUILD_BUG_ON(LRNG_TIME_NUM_VALUES >= (1 << (sizeof(u8) << 3)));
+ BUILD_BUG_ON(LRNG_TIME_ARRAY_MEMBER_BITS % LRNG_TIME_SLOTSIZE_BITS);
+ /* Ensure consistency of values */
+ BUILD_BUG_ON(LRNG_TIME_ARRAY_MEMBER_BITS != sizeof(lrng_time[0]) << 3);
+
+ /* During boot time, we mix the full time stamp directly into LFSR */
+ if (unlikely(!lrng_state_fully_seeded())) {
+
+ /* Seed random32 PRNG with data not used by LRNG. */
+ this_cpu_add(net_rand_state.s1, random32_data);
+
+ if (lrng_raw_hires_entropy_store(now_time))
+ goto out;
+
+ health_test = lrng_health_test(now_time);
+ if (health_test > lrng_health_fail_use)
+ goto out;
+
+ lrng_pool_lfsr_u32(now_time);
+ if (health_test == lrng_health_pass)
+ lrng_pool_add_irq(1);
+ goto out;
+ }
+
+ /* Runtime operation */
+ if (lrng_raw_hires_entropy_store(now_time_masked))
+ goto out;
+
+ /* Seed random32 PRNG with data not used by LRNG. */
+ this_cpu_add(net_rand_state.s1,
+ (now_time & ~LRNG_TIME_SLOTSIZE_MASK) ^ random32_data);
+
+ health_test = lrng_health_test(now_time_masked);
+ if (health_test > lrng_health_fail_use)
+ goto out;
+
+ ptr = this_cpu_inc_return(lrng_time_ptr) & LRNG_TIME_WORD_MASK;
+ this_cpu_or(lrng_time[lrng_time_idx2array(ptr)],
+ lrng_time_slot_val(now_time_masked,
+ lrng_time_idx2slot(ptr)));
+
+ /* Interrupt delivers entropy if health test passes */
+ if (health_test == lrng_health_pass)
+ this_cpu_inc(lrng_time_irqs);
+
+ /* Only mix the buffer of time stamps into LFSR when wrapping */
+ if (ptr < LRNG_TIME_WORD_MASK)
+ goto out;
+
+ for (i = 0; i < LRNG_TIME_ARRAY_SIZE; i++) {
+ if (lrng_raw_array_entropy_store(this_cpu_read(lrng_time[i]))) {
+ /*
+ * If we fed even a part of the array to external
+ * analysis, we mark that the entire array has no
+ * entropy. This is due to the non-IID property of
+ * the data as we do not fully know whether the
+ * existing dependencies diminish the entropy beyond
+ * to what we expect it has.
+ */
+ this_cpu_write(lrng_time_irqs, 0);
+ } else {
+ lrng_pool_lfsr_u32(this_cpu_read(lrng_time[i]));
+ }
+
+ this_cpu_write(lrng_time[i], 0);
+ }
+ lrng_pool_add_irq(this_cpu_read(lrng_time_irqs));
+ this_cpu_write(lrng_time_irqs, 0);
+
+out:
+ lrng_perf_time(now_time);
+}
+
+/*
+ * Hot code path - Callback for interrupt handler
+ */
+void add_interrupt_randomness(int irq, int irq_flags)
+{
+ if (lrng_pool_highres_timer()) {
+ lrng_time_process(
+ (lrng_raw_irq_entropy_store(irq) ? 0 : irq) ^
+ (lrng_raw_irqflags_entropy_store(irq_flags) ? 0 :
+ irq_flags) ^
+ (lrng_raw_retip_entropy_store(_RET_IP_) ? 0 :
+ _RET_IP_));
+ } else {
+ struct pt_regs *regs = get_irq_regs();
+ static atomic_t reg_idx = ATOMIC_INIT(0);
+ u64 ip;
+
+ if (regs) {
+ u32 *ptr = (u32 *)regs;
+ int reg_ptr = atomic_add_return_relaxed(1, ®_idx);
+ size_t n = (sizeof(struct pt_regs) / sizeof(u32));
+
+ ip = instruction_pointer(regs);
+ lrng_pool_lfsr_u32(*(ptr + (reg_ptr % n)));
+
+ lrng_time_process(
+ lrng_raw_retip_entropy_store(_RET_IP_) ? 0 :
+ _RET_IP_);
+ } else {
+ ip = _RET_IP_;
+
+ lrng_time_process(0);
+ }
+
+ /*
+ * The XOR operation combining the different values is not
+ * considered to destroy entropy since the entirety of all
+ * processed values delivers the entropy (and not each
+ * value separately of the other values).
+ */
+ lrng_pool_lfsr_u32(
+ (lrng_raw_jiffies_entropy_store(jiffies) ? 0 :
+ jiffies) ^
+ (lrng_raw_irq_entropy_store(irq) ? 0 : irq) ^
+ (lrng_raw_irqflags_entropy_store(irq_flags) ? 0 :
+ irq_flags) ^
+ (ip >> 32) ^
+ (lrng_raw_retip_entropy_store(ip) ? 0 : ip));
+ }
+}
+EXPORT_SYMBOL(add_interrupt_randomness);
diff --git a/drivers/char/lrng/lrng_sw_noise.h b/drivers/char/lrng/lrng_sw_noise.h
new file mode 100644
index 000000000000..919d8c368991
--- /dev/null
+++ b/drivers/char/lrng/lrng_sw_noise.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * LRNG Slow Noise Source: Time stamp array handling
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+/*
+ * To limit the impact on the interrupt handling, the LRNG concatenates
+ * entropic LSB parts of the time stamps in a per-CPU array and only
+ * injects them into the entropy pool when the array is full.
+ */
+
+/* Store multiple integers in one u32 */
+#define LRNG_TIME_SLOTSIZE_BITS (8)
+#define LRNG_TIME_SLOTSIZE_MASK ((1 << LRNG_TIME_SLOTSIZE_BITS) - 1)
+#define LRNG_TIME_ARRAY_MEMBER_BITS (4 << 3) /* ((sizeof(u32)) << 3) */
+#define LRNG_TIME_SLOTS_PER_UINT (LRNG_TIME_ARRAY_MEMBER_BITS / \
+ LRNG_TIME_SLOTSIZE_BITS)
+
+/*
+ * Number of time values to store in the array - in small environments
+ * only one atomic_t variable per CPU is used.
+ */
+#define LRNG_TIME_NUM_VALUES (CONFIG_BASE_SMALL ? \
+ LRNG_TIME_SLOTS_PER_UINT : 64)
+/* Mask of LSB of time stamp to store */
+#define LRNG_TIME_WORD_MASK (LRNG_TIME_NUM_VALUES - 1)
+
+#define LRNG_TIME_SLOTS_MASK (LRNG_TIME_SLOTS_PER_UINT - 1)
+#define LRNG_TIME_ARRAY_SIZE (LRNG_TIME_NUM_VALUES / \
+ LRNG_TIME_SLOTS_PER_UINT)
+
+/* Starting bit index of slot */
+static inline unsigned int lrng_time_slot2bitindex(unsigned int slot)
+{
+ return (LRNG_TIME_SLOTSIZE_BITS * slot);
+}
+
+/* Convert index into the array index */
+static inline unsigned int lrng_time_idx2array(unsigned int idx)
+{
+ return idx / LRNG_TIME_SLOTS_PER_UINT;
+}
+
+/* Convert index into the slot of a given array index */
+static inline unsigned int lrng_time_idx2slot(unsigned int idx)
+{
+ return idx & LRNG_TIME_SLOTS_MASK;
+}
+
+/* Convert value into slot value */
+static inline unsigned int lrng_time_slot_val(unsigned int val,
+ unsigned int slot)
+{
+ return val << lrng_time_slot2bitindex(slot);
+}
diff --git a/include/linux/lrng.h b/include/linux/lrng.h
new file mode 100644
index 000000000000..2c3d2ed32a91
--- /dev/null
+++ b/include/linux/lrng.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * Copyright (C) 2018 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#ifndef _LRNG_H
+#define _LRNG_H
+
+#include <linux/errno.h>
+#include <linux/types.h>
+
+/**
+ * struct lrng_crypto_cb - cryptographic callback functions
+ * @lrng_drng_name Name of DRNG
+ * @lrng_hash_name Name of Hash used for reading entropy pool
+ * @lrng_drng_alloc: Allocate DRNG -- the provided integer should be
+ * used for sanity checks.
+ * return: allocated data structure or PTR_ERR on
+ * error
+ * @lrng_drng_dealloc: Deallocate DRNG
+ * @lrng_drng_seed_helper: Seed the DRNG with data of arbitrary length
+ * drng: is pointer to data structure allocated
+ * with lrng_drng_alloc
+ * return: >= 0 on success, < 0 on error
+ * @lrng_drng_generate_helper: Generate random numbers from the DRNG with
+ * arbitrary length
+ * @lrng_hash_alloc: Allocate the hash for reading the entropy pool
+ * return: allocated data structure (NULL is
+ * success too) or ERR_PTR on error
+ * @lrng_hash_dealloc: Deallocate Hash
+ * @lrng_hash_digestsize: Return the digestsize for the used hash to read
+ * out entropy pool
+ * hash: is pointer to data structure allocated
+ * with lrng_hash_alloc
+ * return: size of digest of hash in bytes
+ * @lrng_hash_buffer: Generate hash
+ * hash: is pointer to data structure allocated
+ * with lrng_hash_alloc
+ * return: 0 on success, < 0 on error
+ */
+struct lrng_crypto_cb {
+ const char *(*lrng_drng_name)(void);
+ const char *(*lrng_hash_name)(void);
+ void *(*lrng_drng_alloc)(u32 sec_strength);
+ void (*lrng_drng_dealloc)(void *drng);
+ int (*lrng_drng_seed_helper)(void *drng, const u8 *inbuf, u32 inbuflen);
+ int (*lrng_drng_generate_helper)(void *drng, u8 *outbuf, u32 outbuflen);
+ void *(*lrng_hash_alloc)(const u8 *key, u32 keylen);
+ void (*lrng_hash_dealloc)(void *hash);
+ u32 (*lrng_hash_digestsize)(void *hash);
+ int (*lrng_hash_buffer)(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest);
+};
+
+/* Register cryptographic backend */
+#ifdef CONFIG_LRNG_DRNG_SWITCH
+int lrng_set_drng_cb(const struct lrng_crypto_cb *cb);
+#else /* CONFIG_LRNG_DRNG_SWITCH */
+static inline int
+lrng_set_drng_cb(const struct lrng_crypto_cb *cb) { return -EOPNOTSUPP; }
+#endif /* CONFIG_LRNG_DRNG_SWITCH */
+
+#endif /* _LRNG_H */
--
2.26.2
Am Donnerstag, 20. August 2020, 14:07:40 CEST schrieb kernel test robot:
Hi,
>
> All warnings (new ones prefixed by >>):
> >> drivers/char/lrng/lrng_drbg.c:226:1: warning: 'static' is not at
> >> beginning of declaration [-Wold-style-declaration]
> 226 | const static struct lrng_crypto_cb lrng_drbg_crypto_cb = {
>
> | ^~~~~
Thanks, I will provide a new patch set with the two keywords switched.
Ciao
Stephan
Hi "Stephan,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on cryptodev/master crypto/master v5.9-rc1 next-20200820]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200820-165712
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git d162219c655c8cf8003128a13840d6c1e183fb80
config: nios2-allyesconfig (attached as .config)
compiler: nios2-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=nios2
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> drivers/char/lrng/lrng_testing.c:255:15: warning: initialized field overwritten [-Woverride-init]
255 | .rb_reader = 0,
| ^
drivers/char/lrng/lrng_testing.c:255:15: note: (near initialization for 'lrng_raw_hires.rb_reader')
drivers/char/lrng/lrng_testing.c:295:15: warning: initialized field overwritten [-Woverride-init]
295 | .rb_reader = 0,
| ^
drivers/char/lrng/lrng_testing.c:295:15: note: (near initialization for 'lrng_raw_jiffies.rb_reader')
drivers/char/lrng/lrng_testing.c:336:15: warning: initialized field overwritten [-Woverride-init]
336 | .rb_reader = 0,
| ^
drivers/char/lrng/lrng_testing.c:336:15: note: (near initialization for 'lrng_raw_irq.rb_reader')
drivers/char/lrng/lrng_testing.c:376:15: warning: initialized field overwritten [-Woverride-init]
376 | .rb_reader = 0,
| ^
drivers/char/lrng/lrng_testing.c:376:15: note: (near initialization for 'lrng_raw_irqflags.rb_reader')
drivers/char/lrng/lrng_testing.c:417:15: warning: initialized field overwritten [-Woverride-init]
417 | .rb_reader = 0,
| ^
drivers/char/lrng/lrng_testing.c:417:15: note: (near initialization for 'lrng_raw_retip.rb_reader')
drivers/char/lrng/lrng_testing.c:457:15: warning: initialized field overwritten [-Woverride-init]
457 | .rb_reader = 0,
| ^
drivers/char/lrng/lrng_testing.c:457:15: note: (near initialization for 'lrng_raw_array.rb_reader')
drivers/char/lrng/lrng_testing.c:497:15: warning: initialized field overwritten [-Woverride-init]
497 | .rb_reader = 0,
| ^
drivers/char/lrng/lrng_testing.c:497:15: note: (near initialization for 'lrng_irq_perf.rb_reader')
# https://github.com/0day-ci/linux/commit/89b15c614286cea77d633ade2a9045060a492149
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200820-165712
git checkout 89b15c614286cea77d633ade2a9045060a492149
vim +255 drivers/char/lrng/lrng_testing.c
252
253 static struct lrng_testing lrng_raw_hires = {
254 .rb_reader = 0,
> 255 .rb_reader = 0,
256 .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_hires.lock),
257 .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_hires.read_wait)
258 };
259
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Hi,
The following patch set provides a different approach to /dev/random which is
called Linux Random Number Generator (LRNG) to collect entropy within the Linux
kernel. The main improvements compared to the existing /dev/random is to provide
sufficient entropy during boot time as well as in virtual environments and when
using SSDs. A secondary design goal is to limit the impact of the entropy
collection on massive parallel systems and also allow the use accelerated
cryptographic primitives. Also, all steps of the entropic data processing are
testable.
The LRNG patch set allows a user to select use of the existing /dev/random or
the LRNG during compile time. As the LRNG provides API and ABI compatible
interfaces to the existing /dev/random implementation, the user can freely chose
the RNG implementation without affecting kernel or user space operations.
This patch set provides early boot-time entropy which implies that no
additional flags to the getrandom(2) system call discussed recently on
the LKML is considered to be necessary. Yet, if additional flags are
introduced to cover special hardware, the LRNG implementation will also
provide them to be fully ABI and API compliant as already discussed on
LKML.
The LRNG is fully compliant to SP800-90B requirements and is shipped with a
full SP800-90B assessment and all required test tools. The existing /dev/random
implementation on the other hand has architectural limitations which
does not easily allow to bring the implementation in compliance with
SP800-90B. The key statement that causes concern is SP800-90B section
3.1.6. This section denies crediting entropy to multiple similar noise
sources. This section explicitly references different noise sources resting
on the timing of events and their derivatives (i.e. it is a direct complaint
to the existing existing /dev/random implementation). Therefore, SP800-90B
now denies the very issue mentioned in [1] with the existing /dev/random
implementation for a long time: crediting entropy to interrupts as well as
crediting entropy to derivatives of interrupts (HID and disk events). This is
not permissible with SP800-90B.
SP800-90B specifies various requirements for the noise source(s) that seed any
DRNG including SP800-90A DRBGs. In about a year from now, SP800-90B will be
mandated for all noise sources that provide entropy to DRBGs as part of a FIPS
140-[2|3] validation or other evaluation types. That means, if we there are no
solutions to comply with the requirements of SP800-90B found till one year
from now, any random number generation and ciphers based on random numbers
on Linux will be considered and treated as not applicable and delivering
no entropy! As /dev/urandom, getrandom(2) and /dev/random are the most
common and prevalent noise sources for DRNGs, all these DRNGs are affected.
This applies across the board for all validations of cryptography executing on
Linux (kernel and user space modules).
For users that are not interested in SP800-90B, the entire code for the
compliance as well as test interfaces can be deselected at compile time.
The design and implementation is driven by a set of goals described in [1]
that the LRNG completely implements. Furthermore, [1] includes the full
assessment of the SP800-90B compliance as well as a comparison with RNG
design suggestions of SP800-90C, and AIS20/31.
The LRNG provides a complete separation of the noise source maintenance
and the collection of entropy into an entropy pool from the post-processing
using a pseudo-random number generator. Different DRNGs are supported,
including:
* The LRNG can be compile-time enabled to replace the existing /dev/random
implementation. When not selecting the LRNG at compile time (default), the
existing /dev/random implementation is built.
* Built-in ChaCha20 DRNG which has no dependency to other kernel
frameworks.
* SP800-90A DRBG using the kernel crypto API including its accelerated
raw cipher implementations. This implies that the output of /dev/random,
getrandom(2), /dev/urandom or get_random_bytes is fully compliant to
SP800-90A.
* Arbitrary DRNGs registered with the kernel crypto API
* Full compliance with SP800-90B which covers the startup and runtime health
tests mandated by SP800-90B as well as providing the test tools and test
interfaces to obtain raw noise data securely. The test tools are provided at
[1].
Booting the patch with the kernel command line option
"dyndbg=file drivers/char/lrng/* +p" generates logs indicating the operation
of the LRNG. Each log is pre-pended with "lrng".
The LRNG has a flexible design by allowing an easy replacement of the
deterministic random number generator component.
Compared to the existing /dev/random implementation, the compiled binary
is smaller when the LRNG is compiled with all options equal to the
existing /dev/random (i.e. only CONFIG_LRNG is set): random.o is 52.5 kBytes
whereas all LRNG object files are in 49 kBytes in size. The fully
SP800-90A/SP800-90B compliant binary code (CONFIG_LRNG,
CONFIG_LRNG_DRNG_SWITCH, CONFIG_LRNG_DRBG, CONFIG_LRNG_HEALTH_TESTS)
uses some 61 kBytes. In addition, the LRNG is about 50% faster in the
performance critical interrupt handler code path compared to the existing
/dev/random implementation.
Full SP800-90B testing is performed on the following systems - details
are given in [2] appendix C:
* x86 KVM virtualized guest 32 and 64 bit systems
* x86 bare metal
* older and newer ARMv7 system
* ARM64
* POWER7 LE and POWER 8 BE
* IBM Z System mainframe
* old MIPS embedded device
[1] https://www.chronox.de/lrng.html - If the patch is accepted, I would
be volunteering to convert the documentation into RST format and
contribute it to the Linux kernel documentation directory.
[2] https://www.chronox.de/lrng/doc/lrng.pdf
Changes (compared to the previous patch set):
* fix const static -> static const as indicated by kernel test robot
* fix double initialization as indicated by kernel test robot
* add hw_random.h header file and add get_random_bytes_full prototypes
as indicated by kernel test robot
* if -> ifdef for CONFIG_CRYPTO_LIB_SHA256 in lrng_selftest.c
* Note, the warning on random_table is expected as it is there to ensure
patch 0001 can be compiled. This symbol is "fixed" with patch 0003.
As a side node: With the switchable DRNG support offered in this patch set,
the following areas could be removed. As the existing /dev/random has no support
for switchable DRNGs, however, this is not yet feasible though.
* remove lrng_ready_list and all code around it in lrng_interfaces.c
* remove the kernel crypto API RNG API to avoid having two random number
providing APIs - this would imply that all RNGs developed for this API would
be converted to the LRNG interface
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Stephan Mueller (12):
Linux Random Number Generator
LRNG - allocate one DRNG instance per NUMA node
LRNG - sysctls and /proc interface
LRNG - add switchable DRNG support
crypto: DRBG - externalize DRBG functions for LRNG
LRNG - add SP800-90A DRBG extension
LRNG - add kernel crypto API PRNG extension
crypto: provide access to a static Jitter RNG state
LRNG - add Jitter RNG fast noise source
LRNG - add SP800-90B compliant health tests
LRNG - add interface for gathering of raw entropy
LRNG - add power-on and runtime self-tests
MAINTAINERS | 7 +
crypto/drbg.c | 16 +-
crypto/jitterentropy-kcapi.c | 3 +-
crypto/jitterentropy.c | 31 +-
drivers/char/Kconfig | 2 +
drivers/char/Makefile | 9 +-
drivers/char/lrng/Kconfig | 315 +++++++++
drivers/char/lrng/Makefile | 19 +
drivers/char/lrng/lrng_archrandom.c | 93 +++
drivers/char/lrng/lrng_aux.c | 136 ++++
drivers/char/lrng/lrng_chacha20.c | 320 +++++++++
drivers/char/lrng/lrng_chacha20.h | 29 +
drivers/char/lrng/lrng_drbg.c | 259 +++++++
drivers/char/lrng/lrng_drng.c | 409 +++++++++++
drivers/char/lrng/lrng_health.c | 407 +++++++++++
drivers/char/lrng/lrng_interfaces.c | 648 ++++++++++++++++++
drivers/char/lrng/lrng_internal.h | 345 ++++++++++
drivers/char/lrng/lrng_jent.c | 88 +++
drivers/char/lrng/lrng_kcapi.c | 321 +++++++++
drivers/char/lrng/lrng_lfsr.h | 152 ++++
drivers/char/lrng/lrng_numa.c | 101 +++
drivers/char/lrng/lrng_pool.c | 589 ++++++++++++++++
drivers/char/lrng/lrng_proc.c | 163 +++++
drivers/char/lrng/lrng_selftest.c | 504 ++++++++++++++
drivers/char/lrng/lrng_sw_noise.c | 155 +++++
drivers/char/lrng/lrng_sw_noise.h | 57 ++
drivers/char/lrng/lrng_switch.c | 189 +++++
drivers/char/lrng/lrng_testing.c | 575 ++++++++++++++++
include/crypto/drbg.h | 7 +
.../crypto/internal}/jitterentropy.h | 3 +
include/linux/lrng.h | 63 ++
31 files changed, 6005 insertions(+), 10 deletions(-)
create mode 100644 drivers/char/lrng/Kconfig
create mode 100644 drivers/char/lrng/Makefile
create mode 100644 drivers/char/lrng/lrng_archrandom.c
create mode 100644 drivers/char/lrng/lrng_aux.c
create mode 100644 drivers/char/lrng/lrng_chacha20.c
create mode 100644 drivers/char/lrng/lrng_chacha20.h
create mode 100644 drivers/char/lrng/lrng_drbg.c
create mode 100644 drivers/char/lrng/lrng_drng.c
create mode 100644 drivers/char/lrng/lrng_health.c
create mode 100644 drivers/char/lrng/lrng_interfaces.c
create mode 100644 drivers/char/lrng/lrng_internal.h
create mode 100644 drivers/char/lrng/lrng_jent.c
create mode 100644 drivers/char/lrng/lrng_kcapi.c
create mode 100644 drivers/char/lrng/lrng_lfsr.h
create mode 100644 drivers/char/lrng/lrng_numa.c
create mode 100644 drivers/char/lrng/lrng_pool.c
create mode 100644 drivers/char/lrng/lrng_proc.c
create mode 100644 drivers/char/lrng/lrng_selftest.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.h
create mode 100644 drivers/char/lrng/lrng_switch.c
create mode 100644 drivers/char/lrng/lrng_testing.c
rename {crypto => include/crypto/internal}/jitterentropy.h (84%)
create mode 100644 include/linux/lrng.h
--
2.26.2
In an effort to provide a flexible implementation for a random number
generator that also delivers entropy during early boot time, allows
replacement of the deterministic random number generation mechanism,
implement the various components in separate code for easier
maintenance, and provide compliance to SP800-90[A|B|C], introduce
the Linux Random Number Generator (LRNG) framework.
The general design is as follows. Additional implementation details
are given in [1]. The LRNG consists of the following components:
1. The LRNG implements a DRNG. The DRNG always generates the
requested amount of output. When using the SP800-90A terminology
it operates without prediction resistance. The secondary DRNG
maintains a counter of how many bytes were generated since last
re-seed and a timer of the elapsed time since last re-seed. If either
the counter or the timer reaches a threshold, the secondary DRNG is
seeded from the entropy pool.
In case the Linux kernel detects a NUMA system, one secondary DRNG
instance per NUMA node is maintained.
2. The DRNG is seeded by concatenating the data from the
following sources:
(a) the output of the entropy pool,
(b) the Jitter RNG if available and enabled, and
(c) the CPU-based noise source such as Intel RDRAND if available and
enabled.
The entropy estimate of the data of all noise sources are added to
form the entropy estimate of the data used to seed the DRNG with.
The LRNG ensures, however, that the DRNG after seeding is at
maximum the security strength of the DRNG.
The LRNG is designed such that none of these noise sources can dominate
the other noise sources to provide seed data to the DRNG during due to
the following:
(a) During boot time, the amount of received interrupts are the trigger
points to (re)seed the DRNG.
(b) At runtime, the available entropy from the slow noise source is
concatenated with a pre-defined amount of data from the fast noise
sources. In addition, each DRNG reseed operation triggers external
noise source providers to deliver one block of data.
3. The entropy pool accumulates entropy obtained from certain events,
which will henceforth be collectively called "slow noise sources".
The entropy pool collects noise data from slow noise sources. Any data
received by the LRNG from the slow noise sources is inserted into the
entropy pool using an LFSR with a primitive and irreducible polynomial.
The following sources of entropy are used:
(a) When an interrupt occurs, the high-resolution time stamp is mixed
into the LFSR. This time stamp is credited with heuristically implied
entropy.
(b) HID event data like the key stroke or the mouse coordinates are
mixed into the LFSR. This data is not credited with entropy by the LRNG.
(c) Device drivers may provide data that is mixed into the LFSR. This
data is not credited with entropy by the LRNG.
(d) After the entropy pool is ``read'' by the DRNG, the data
used to seed the DRNG is mixed back into the entropy pool to
stir the pool. This data is not credited with entropy by the LRNG.
Any data provided from user space by either writing to /dev/random,
/dev/urandom or the IOCTL of RNDADDENTROPY on both device files
are always injected into the entropy pool.
In addition, when a hardware random number generator covered by the
Linux kernel HW generator framework wants to deliver random numbers,
it is injected into the entropy pool as well. HW generator noise source
is handled separately from the other noise source due to the fact that
the HW generator framework may decide by itself when to deliver data
whereas the other noise sources always requested for data driven by the
LRNG operation. Similarly any user space provided data is inserted into
the entropy pool.
When the DRNG requires data from the entropy pool, the entire
entropy pool is processed with an SP800-90A section 10.3.1 compliant
hash_df function to generate random numbers.
To speed up the interrupt handling code of the LRNG, the time stamp
collected for an interrupt event is truncated to the 8 least
significant bits. 64 truncated time stamps are concatenated and then
jointly inserted into the LFSR. During boot time, until the fully seeded
stage is reached, each time stamp with its 32 least significant bits is
inserted into the LFSR at the time of arrival.
The LRNG allows the DRNG mechanism to be changed at runtime. Per default,
a ChaCha20-based DRNG is used. The ChaCha20-DRNG implemented for the
LRNG is also provided as a stand-alone user space deterministic random
number generator. The LRNG also offers an SP800-90A DRBG based on the
Linux kernel crypto API DRBG implementation.
The processing of entropic data from the noise source before injecting
them into the DRNG is performed with the following mathematical
operations:
1. LFSR: The 8 least significant bits of the time stamp data received
from the interrupts are processed with an LFSR. That LFSR is implemented
identically to the LSFR used in the existing /dev/random implementation
except that it is capable of processing an entire word and that a
different polynomial is used. The reason for the different polynomial
is performance in a performance sensitive code section, the interrupt
handler. The chosen polynomials have 4 taps. Also, this LFSR-approach
is used in the OpenBSD /dev/random equivalent.
2. Concatenation: The temporary seed buffer used to seed the DRNG is
a concatenation of parts of the entropy pool data, and the CPU noise
source output.
The DRNG always tries to seed itself with 256 bits of entropy, except
during boot. In any case, if the noise sources cannot deliver that
amount, the available entropy is used and the DRNG keeps track on how
much entropy it was seeded with. The entropy implied by the LRNG
available in the entropy pool may be too conservative. To ensure
that during boot time all available entropy from the entropy pool is
transferred to the DRNG, the hash_df function always generates 256
data bits during boot to seed the DRNG. During boot, the DRNG is
seeded as follows:
1. The DRNG is reseeded from the entropy pool and potentially the fast
noise sources if the entropy pool has collected at least 32 bits of
entropy from the interrupt noise source. The goal of this step is to
ensure that the DRNG receives some initial entropy as early as
possible. In addition it receives the entropy available from
the fast noise sources.
2. The DRNG is reseeded from the entropy pool and potentially the fast
noise sources if all noise sources collectively can provide at least
128 bits of entropy.
3. The DRNG is reseeded from the entropy pool and potentially the fast
noise sources if all noise sources collectivel can provide at least 256
bits.
At the time of the reseeding steps, the DRNG requests as much entropy as
is available in order to skip certain steps and reach the seeding level
of 256 bits. This may imply that one or more of the aforementioned steps
are skipped.
In all listed steps, the DRNG is (re)seeded with a number of random
bytes from the entropy pool that is at most the amount of entropy
present in the entropy pool. This means that when the entropy pool
contains 128 or 256 bits of entropy, the DRNG is seeded with that
amount of entropy as well.
Before the DRNG is seeded with 256 bits of entropy in step 3,
requests of random data from /dev/random are not processed.
The hash_df operation providing random data from the entropy pool will
always require that all entropy sources collectively can deliver at
least 129 entropy bits as configured with (128 bits of entropy for
seeding plus one bit of entropy that is lost with the post
processing as defined in SP800-90B).
The DRNG operates as deterministic random number generator with the
following properties:
* The maximum number of random bytes that can be generated with one
DRNG generate operation is limited to 4096 bytes. When longer random
numbers are requested, multiple DRNG generate operations are performed.
The ChaCha20 DRNG as well as the SP800-90A DRBGs implement an update of
their state after completing a generate request for backtracking
resistance.
* The secondary DRNG is reseeded with whatever entropy is available –
in the worst case where no additional entropy can be provided by the
noise sources, the DRNG is not re-seeded and continues its operation
to try to reseed again after again the expiry of one of these thresholds:
- If the last reseeding of the secondary DRNG is more than 600 seconds
ago, or
- 2^20 DRNG generate operations are performed, whatever comes first, or
- the secondary DRNG is forced to reseed before the next generation of
random numbers if data has been injected into the LRNG by writing data
into /dev/random or /dev/urandom.
The chosen values prevent high-volume requests from user space to cause
frequent reseeding operations which drag down the performance of the
DRNG.
With the automatic reseeding after 600 seconds, the LRNG is triggered
to reseed itself before the first request after a suspend that put the
hardware to sleep for longer than 600 seconds.
The LRNG uses the following runtime memory using the currently
smallest configuration:
* 576 bytes (512 bytes for the entropy pool and 64 for the entropy pool
meta data) for the entropy pool management
* 64 bytes per CPU for the time stamp array
To support smaller devices including IoT environments, this patch
allows reducing the runtime memory footprint of the LRNG at compile
time by selecting smaller entropy pool sizes.
The entropy pool has support for sizes of 256, 128 and 64 bytes supported
by primitive and irreducible polynomials.
The time stamp array is reduced to one atomic_t variable per CPU, i.e.
4 bytes when CONFIG_BASE_SMALL is selected during kernel
configuration. This implies that after the receipt of 4 interrupts on
one CPU, the data is injected into the LFSR. Depending on the behavior
of the CPU caches, this may imply that the average interrupt handler
execution time increases a bit, since instead of injecting 8 atomic_t
values at one given time into the LFSR, only one is processed which
may incur cache misses.
When selecting the compilation of a kernel for a small environment,
prevent the allocation of a buffer up to 4096 bytes to serve user space
requests. In this case, the stack variable of 64 bytes is used to serve
all user space requests.
The LRNG has the following properties:
* internal noise source: interrupts timing with fast boot time seeding
* high performance of interrupt handling code: The LRNG impact on the
interrupt handling has been reduced to a minimum. On one example
system, the LRNG interrupt handling code executes within an average
of 65 cycles whereas the existing /dev/random on the same device
takes about 97 cycles when measuring the execution time of
add_interrupt_randomness().
* lockless LFSR to collect raw entropy supporing concurrency-free
use of massive parallel systems
* use of standalone ChaCha20 based RNG with the option to use a
different DRNG selectable at compile time
* "atomic" seeding of secondary DRBG to ensure full entropy transport
* instantiate one DRNG per NUMA node
* support for runtime switchable output DRNGs
* use of only well-defined entropy-preserving operations to collect,
compress and forward entropy: concatenation, LFSR, SP800-90A hash_df
function
* compile-time selectable entropy pool size: the choice also
uses the applicable LFSR polynomial to maintain the entropy pool
size
* support of small systems by allowing the reduction of the
runtime memory needs
Further details including the rationale for the design choices and
properties of the LRNG together with testing is provided at [1].
In addition, the documentation explains the conducted regression
tests to verify that the LRNG is API and ABI compatible with the
existing /dev/random implementation.
[1] https://www.chronox.de/lrng.html
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Mathematical aspects Reviewed-by: "Peter, Matthias" <[email protected]>
Reviewed-by: Marcelo Henrique Cerri <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtmüller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
MAINTAINERS | 7 +
drivers/char/Kconfig | 2 +
drivers/char/Makefile | 9 +-
drivers/char/lrng/Kconfig | 68 +++
drivers/char/lrng/Makefile | 9 +
drivers/char/lrng/lrng_archrandom.c | 93 ++++
drivers/char/lrng/lrng_aux.c | 136 ++++++
drivers/char/lrng/lrng_chacha20.c | 320 ++++++++++++++
drivers/char/lrng/lrng_chacha20.h | 29 ++
drivers/char/lrng/lrng_drng.c | 409 ++++++++++++++++++
drivers/char/lrng/lrng_interfaces.c | 649 ++++++++++++++++++++++++++++
drivers/char/lrng/lrng_internal.h | 336 ++++++++++++++
drivers/char/lrng/lrng_lfsr.h | 152 +++++++
drivers/char/lrng/lrng_pool.c | 589 +++++++++++++++++++++++++
drivers/char/lrng/lrng_sw_noise.c | 155 +++++++
drivers/char/lrng/lrng_sw_noise.h | 57 +++
include/linux/lrng.h | 63 +++
17 files changed, 3082 insertions(+), 1 deletion(-)
create mode 100644 drivers/char/lrng/Kconfig
create mode 100644 drivers/char/lrng/Makefile
create mode 100644 drivers/char/lrng/lrng_archrandom.c
create mode 100644 drivers/char/lrng/lrng_aux.c
create mode 100644 drivers/char/lrng/lrng_chacha20.c
create mode 100644 drivers/char/lrng/lrng_chacha20.h
create mode 100644 drivers/char/lrng/lrng_drng.c
create mode 100644 drivers/char/lrng/lrng_interfaces.c
create mode 100644 drivers/char/lrng/lrng_internal.h
create mode 100644 drivers/char/lrng/lrng_lfsr.h
create mode 100644 drivers/char/lrng/lrng_pool.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.h
create mode 100644 include/linux/lrng.h
diff --git a/MAINTAINERS b/MAINTAINERS
index deaafb617361..74f6fd1ba1ec 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10084,6 +10084,13 @@ F: Documentation/litmus-tests/
F: Documentation/memory-barriers.txt
F: tools/memory-model/
+LINUX RANDOM NUMBER GENERATOR (LRNG) DRIVER
+M: Stephan Mueller <[email protected]>
+S: Maintained
+W: https://www.chronox.de/lrng.html
+F: drivers/char/lrng/*
+F: include/linux/lrng.h
+
LIS3LV02D ACCELEROMETER DRIVER
M: Eric Piel <[email protected]>
S: Maintained
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index b1bd336761b1..8a5b8a2db2c7 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -470,6 +470,8 @@ config ADI
and SSM (Silicon Secured Memory). Intended consumers of this
driver include crash and makedumpfile.
+source "drivers/char/lrng/Kconfig"
+
endmenu
config RANDOM_TRUST_CPU
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index ffce287ef415..2110d3e28cf2 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -3,7 +3,14 @@
# Makefile for the kernel character device drivers.
#
-obj-y += mem.o random.o
+obj-y += mem.o
+
+ifeq ($(CONFIG_LRNG),y)
+ obj-y += lrng/
+else
+ obj-y += random.o
+endif
+
obj-$(CONFIG_TTY_PRINTK) += ttyprintk.o
obj-y += misc.o
obj-$(CONFIG_ATARI_DSP56K) += dsp56k.o
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
new file mode 100644
index 000000000000..059b21d9728c
--- /dev/null
+++ b/drivers/char/lrng/Kconfig
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Linux Random Number Generator configuration
+#
+
+menuconfig LRNG
+ bool "Linux Random Number Generator"
+ select CRYPTO_LIB_SHA256 if CRYPTO
+ help
+ The Linux Random Number Generator (LRNG) is the replacement
+ of the existing /dev/random provided with drivers/char/random.c.
+ It generates entropy from different noise sources and
+ delivers significant entropy during boot.
+
+if LRNG
+
+choice
+ prompt "LRNG Entropy Pool Size"
+ default LRNG_POOL_SIZE_4096
+ help
+ Select the size of the LRNG entropy pool. The size of the
+ entropy pool is relevant for the amount of entropy that
+ the LRNG can maintain as a maximum. The larger the size
+ of the entropy pool is the more entropy can be maintained
+ but the less often older entropic values are overwritten
+ with new entropy.
+
+ config LRNG_POOL_SIZE_512
+ bool "512 bits"
+
+ config LRNG_POOL_SIZE_1024
+ bool "1024 bits"
+
+ config LRNG_POOL_SIZE_2048
+ bool "2048 bits"
+
+ config LRNG_POOL_SIZE_4096
+ bool "4096 bits (default)"
+
+ config LRNG_POOL_SIZE_8192
+ bool "8192 bits"
+
+ config LRNG_POOL_SIZE_16384
+ bool "16384 bits"
+
+ config LRNG_POOL_SIZE_32768
+ bool "32768 bits"
+
+ config LRNG_POOL_SIZE_65536
+ bool "65536 bits"
+
+ config LRNG_POOL_SIZE_131072
+ bool "131072 bits"
+endchoice
+
+config LRNG_POOL_SIZE
+ int
+ default 0 if LRNG_POOL_SIZE_512
+ default 1 if LRNG_POOL_SIZE_1024
+ default 2 if LRNG_POOL_SIZE_2048
+ default 3 if LRNG_POOL_SIZE_4096
+ default 4 if LRNG_POOL_SIZE_8192
+ default 5 if LRNG_POOL_SIZE_16384
+ default 6 if LRNG_POOL_SIZE_32768
+ default 7 if LRNG_POOL_SIZE_65536
+ default 8 if LRNG_POOL_SIZE_131072
+
+endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
new file mode 100644
index 000000000000..1d2a0211973d
--- /dev/null
+++ b/drivers/char/lrng/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux Random Number Generator.
+#
+
+obj-y += lrng_pool.o lrng_aux.o \
+ lrng_sw_noise.o lrng_archrandom.o \
+ lrng_drng.o lrng_chacha20.o \
+ lrng_interfaces.o \
diff --git a/drivers/char/lrng/lrng_archrandom.c b/drivers/char/lrng/lrng_archrandom.c
new file mode 100644
index 000000000000..5e81c4e856d5
--- /dev/null
+++ b/drivers/char/lrng/lrng_archrandom.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Fast Noise Source: CPU-based noise source
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/random.h>
+
+#include "lrng_internal.h"
+
+/*
+ * Estimated entropy of data is a 32th of LRNG_DRNG_SECURITY_STRENGTH_BITS.
+ * As we have no ability to review the implementation of those noise sources,
+ * it is prudent to have a conservative estimate here.
+ */
+#define LRNG_ARCHRANDOM_DEFAULT_STRENGTH (LRNG_DRNG_SECURITY_STRENGTH_BITS>>5)
+#define LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH LRNG_DRNG_SECURITY_STRENGTH_BITS
+#ifdef CONFIG_RANDOM_TRUST_CPU
+static u32 archrandom = LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH;
+#else
+static u32 archrandom = LRNG_ARCHRANDOM_DEFAULT_STRENGTH;
+#endif
+module_param(archrandom, uint, 0644);
+MODULE_PARM_DESC(archrandom, "Entropy in bits of 256 data bits from CPU noise source (e.g. RDRAND)");
+
+static int __init lrng_parse_trust_cpu(char *arg)
+{
+ int ret;
+ bool trust_cpu = false;
+
+ ret = kstrtobool(arg, &trust_cpu);
+ if (ret)
+ return ret;
+
+ if (trust_cpu)
+ archrandom = LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH;
+ else
+ archrandom = LRNG_ARCHRANDOM_DEFAULT_STRENGTH;
+
+ return 0;
+}
+early_param("random.trust_cpu", lrng_parse_trust_cpu);
+
+/**
+ * lrng_get_arch() - Get CPU noise source entropy
+ *
+ * @outbuf: buffer to store entropy of size LRNG_DRNG_SECURITY_STRENGTH_BYTES
+ *
+ * Return:
+ * * > 0 on success where value provides the added entropy in bits
+ * * 0 if no fast source was available
+ */
+u32 lrng_get_arch(u8 *outbuf)
+{
+ u32 i, ent_bits = archrandom;
+
+ /* operate on full blocks */
+ BUILD_BUG_ON(LRNG_DRNG_SECURITY_STRENGTH_BYTES % sizeof(unsigned long));
+ /* ensure we have aligned buffers */
+ BUILD_BUG_ON(LRNG_KCAPI_ALIGN % sizeof(unsigned long));
+
+ if (!ent_bits)
+ return 0;
+
+ for (i = 0; i < LRNG_DRNG_SECURITY_STRENGTH_BYTES;
+ i += sizeof(unsigned long)) {
+ if (!arch_get_random_seed_long((unsigned long *)(outbuf + i)) &&
+ !arch_get_random_long((unsigned long *)(outbuf + i))) {
+ archrandom = 0;
+ return 0;
+ }
+ }
+
+ /* Obtain entropy statement -- cap entropy to buffer size in bits */
+ ent_bits = min_t(u32, ent_bits, LRNG_DRNG_SECURITY_STRENGTH_BITS);
+ pr_debug("obtained %u bits of entropy from CPU RNG noise source\n",
+ ent_bits);
+ return ent_bits;
+}
+
+u32 lrng_slow_noise_req_entropy(u32 required_entropy_bits)
+{
+ u32 arch_ent_bits = min_t(u32, archrandom,
+ LRNG_DRNG_SECURITY_STRENGTH_BITS);
+ u32 fast_noise_entropy = arch_ent_bits + lrng_jent_entropylevel();
+
+ if (fast_noise_entropy > required_entropy_bits)
+ return 0;
+ return (required_entropy_bits - fast_noise_entropy);
+}
diff --git a/drivers/char/lrng/lrng_aux.c b/drivers/char/lrng/lrng_aux.c
new file mode 100644
index 000000000000..9f46c5707517
--- /dev/null
+++ b/drivers/char/lrng/lrng_aux.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG auxiliary interfaces
+ *
+ * Copyright (C) 2019 Stephan Mueller <[email protected]>
+ * Copyright (C) 2017 Jason A. Donenfeld <[email protected]>. All
+ * Rights Reserved.
+ * Copyright (C) 2016 Jason Cooper <[email protected]>
+ */
+
+#include <linux/mm.h>
+#include <linux/random.h>
+
+#include "lrng_internal.h"
+
+struct batched_entropy {
+ union {
+ u64 entropy_u64[LRNG_DRNG_BLOCKSIZE / sizeof(u64)];
+ u32 entropy_u32[LRNG_DRNG_BLOCKSIZE / sizeof(u32)];
+ };
+ unsigned int position;
+ spinlock_t batch_lock;
+};
+
+/*
+ * Get a random word for internal kernel use only. The quality of the random
+ * number is as good as /dev/urandom, but there is no backtrack protection,
+ * with the goal of being quite fast and not depleting entropy.
+ */
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64) = {
+ .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u64.lock),
+};
+
+u64 get_random_u64(void)
+{
+ u64 ret;
+ unsigned long flags;
+ struct batched_entropy *batch;
+
+ lrng_debug_report_seedlevel("get_random_u64");
+
+ batch = raw_cpu_ptr(&batched_entropy_u64);
+ spin_lock_irqsave(&batch->batch_lock, flags);
+ if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) {
+ lrng_drng_get_atomic((u8 *)batch->entropy_u64,
+ LRNG_DRNG_BLOCKSIZE);
+ batch->position = 0;
+ }
+ ret = batch->entropy_u64[batch->position++];
+ spin_unlock_irqrestore(&batch->batch_lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(get_random_u64);
+
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32) = {
+ .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u32.lock),
+};
+
+u32 get_random_u32(void)
+{
+ u32 ret;
+ unsigned long flags;
+ struct batched_entropy *batch;
+
+ lrng_debug_report_seedlevel("get_random_u32");
+
+ batch = raw_cpu_ptr(&batched_entropy_u32);
+ spin_lock_irqsave(&batch->batch_lock, flags);
+ if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) {
+ lrng_drng_get_atomic((u8 *)batch->entropy_u32,
+ LRNG_DRNG_BLOCKSIZE);
+ batch->position = 0;
+ }
+ ret = batch->entropy_u32[batch->position++];
+ spin_unlock_irqrestore(&batch->batch_lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(get_random_u32);
+
+/*
+ * It's important to invalidate all potential batched entropy that might
+ * be stored before the crng is initialized, which we can do lazily by
+ * simply resetting the counter to zero so that it's re-extracted on the
+ * next usage.
+ */
+void invalidate_batched_entropy(void)
+{
+ int cpu;
+ unsigned long flags;
+
+ for_each_possible_cpu(cpu) {
+ struct batched_entropy *batched_entropy;
+
+ batched_entropy = per_cpu_ptr(&batched_entropy_u32, cpu);
+ spin_lock_irqsave(&batched_entropy->batch_lock, flags);
+ batched_entropy->position = 0;
+ spin_unlock(&batched_entropy->batch_lock);
+
+ batched_entropy = per_cpu_ptr(&batched_entropy_u64, cpu);
+ spin_lock(&batched_entropy->batch_lock);
+ batched_entropy->position = 0;
+ spin_unlock_irqrestore(&batched_entropy->batch_lock, flags);
+ }
+}
+
+/**
+ * randomize_page - Generate a random, page aligned address
+ * @start: The smallest acceptable address the caller will take.
+ * @range: The size of the area, starting at @start, within which the
+ * random address must fall.
+ *
+ * If @start + @range would overflow, @range is capped.
+ *
+ * NOTE: Historical use of randomize_range, which this replaces, presumed that
+ * @start was already page aligned. We now align it regardless.
+ *
+ * Return: A page aligned address within [start, start + range). On error,
+ * @start is returned.
+ */
+unsigned long randomize_page(unsigned long start, unsigned long range)
+{
+ if (!PAGE_ALIGNED(start)) {
+ range -= PAGE_ALIGN(start) - start;
+ start = PAGE_ALIGN(start);
+ }
+
+ if (start > ULONG_MAX - range)
+ range = ULONG_MAX - start;
+
+ range >>= PAGE_SHIFT;
+
+ if (range == 0)
+ return start;
+
+ return start + (get_random_long() % range << PAGE_SHIFT);
+}
diff --git a/drivers/char/lrng/lrng_chacha20.c b/drivers/char/lrng/lrng_chacha20.c
new file mode 100644
index 000000000000..9da139d89959
--- /dev/null
+++ b/drivers/char/lrng/lrng_chacha20.c
@@ -0,0 +1,320 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Backend for the LRNG providing the cryptographic primitives using
+ * ChaCha20 cipher implementations.
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <crypto/chacha.h>
+#include <crypto/sha.h>
+#include <linux/lrng.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+
+#include "lrng_chacha20.h"
+#include "lrng_internal.h"
+
+/******************************* ChaCha20 DRNG *******************************/
+
+#define CHACHA_BLOCK_WORDS (CHACHA_BLOCK_SIZE / sizeof(u32))
+
+struct chacha20_state {
+ struct chacha20_block block;
+};
+
+/*
+ * Have a static memory blocks for the ChaCha20 DRNG instance to avoid calling
+ * kmalloc too early in the boot cycle. For subsequent allocation requests,
+ * such as per-NUMA-node DRNG instances, kmalloc will be used.
+ */
+struct chacha20_state chacha20;
+
+/**
+ * Update of the ChaCha20 state by either using an unused buffer part or by
+ * generating one ChaCha20 block which is half of the state of the ChaCha20.
+ * The block is XORed into the key part of the state. This shall ensure
+ * backtracking resistance as well as a proper mix of the ChaCha20 state once
+ * the key is injected.
+ */
+static void lrng_chacha20_update(struct chacha20_state *chacha20_state,
+ u32 *buf, u32 used_words)
+{
+ struct chacha20_block *chacha20 = &chacha20_state->block;
+ u32 i, tmp[CHACHA_BLOCK_WORDS];
+
+ BUILD_BUG_ON(sizeof(struct chacha20_block) != CHACHA_BLOCK_SIZE);
+ BUILD_BUG_ON(CHACHA_BLOCK_SIZE != 2 * CHACHA_KEY_SIZE);
+
+ if (used_words > CHACHA_KEY_SIZE_WORDS) {
+ chacha20_block(&chacha20->constants[0], (u8 *)tmp);
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++)
+ chacha20->key.u[i] ^= le32_to_cpu(tmp[i]);
+ memzero_explicit(tmp, sizeof(tmp));
+ } else {
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++)
+ chacha20->key.u[i] ^= le32_to_cpu(buf[i + used_words]);
+ }
+
+ /* Deterministic increment of nonce as required in RFC 7539 chapter 4 */
+ chacha20->nonce[0]++;
+ if (chacha20->nonce[0] == 0)
+ chacha20->nonce[1]++;
+ if (chacha20->nonce[1] == 0)
+ chacha20->nonce[2]++;
+
+ /* Leave counter untouched as it is start value is undefined in RFC */
+}
+
+/*
+ * Seed the ChaCha20 DRNG by injecting the input data into the key part of
+ * the ChaCha20 state. If the input data is longer than the ChaCha20 key size,
+ * perform a ChaCha20 operation after processing of key size input data.
+ * This operation shall spread out the entropy into the ChaCha20 state before
+ * new entropy is injected into the key part.
+ */
+static int lrng_cc20_drng_seed_helper(void *drng, const u8 *inbuf, u32 inbuflen)
+{
+ struct chacha20_state *chacha20_state = (struct chacha20_state *)drng;
+ struct chacha20_block *chacha20 = &chacha20_state->block;
+
+ while (inbuflen) {
+ u32 i, todo = min_t(u32, inbuflen, CHACHA_KEY_SIZE);
+
+ for (i = 0; i < todo; i++)
+ chacha20->key.b[i] ^= inbuf[i];
+
+ /* Break potential dependencies between the inbuf key blocks */
+ lrng_chacha20_update(chacha20_state, NULL,
+ CHACHA_BLOCK_WORDS);
+ inbuf += todo;
+ inbuflen -= todo;
+ }
+
+ return 0;
+}
+
+/*
+ * Chacha20 DRNG generation of random numbers: the stream output of ChaCha20
+ * is the random number. After the completion of the generation of the
+ * stream, the entire ChaCha20 state is updated.
+ *
+ * Note, as the ChaCha20 implements a 32 bit counter, we must ensure
+ * that this function is only invoked for at most 2^32 - 1 ChaCha20 blocks
+ * before a reseed or an update happens. This is ensured by the variable
+ * outbuflen which is a 32 bit integer defining the number of bytes to be
+ * generated by the ChaCha20 DRNG. At the end of this function, an update
+ * operation is invoked which implies that the 32 bit counter will never be
+ * overflown in this implementation.
+ */
+static int lrng_cc20_drng_generate_helper(void *drng, u8 *outbuf, u32 outbuflen)
+{
+ struct chacha20_state *chacha20_state = (struct chacha20_state *)drng;
+ struct chacha20_block *chacha20 = &chacha20_state->block;
+ u32 aligned_buf[CHACHA_BLOCK_WORDS], ret = outbuflen,
+ used = CHACHA_BLOCK_WORDS;
+ int zeroize_buf = 0;
+
+ while (outbuflen >= CHACHA_BLOCK_SIZE) {
+ chacha20_block(&chacha20->constants[0], outbuf);
+ outbuf += CHACHA_BLOCK_SIZE;
+ outbuflen -= CHACHA_BLOCK_SIZE;
+ }
+
+ if (outbuflen) {
+ chacha20_block(&chacha20->constants[0], (u8 *)aligned_buf);
+ memcpy(outbuf, aligned_buf, outbuflen);
+ used = ((outbuflen + sizeof(aligned_buf[0]) - 1) /
+ sizeof(aligned_buf[0]));
+ zeroize_buf = 1;
+ }
+
+ lrng_chacha20_update(chacha20_state, aligned_buf, used);
+
+ if (zeroize_buf)
+ memzero_explicit(aligned_buf, sizeof(aligned_buf));
+
+ return ret;
+}
+
+void lrng_cc20_init_state(struct chacha20_state *state)
+{
+ struct chacha20_block *chacha20 = &state->block;
+ unsigned long v;
+ u32 i;
+
+ lrng_cc20_init_rfc7539(chacha20);
+
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) {
+ chacha20->key.u[i] ^= jiffies;
+ chacha20->key.u[i] ^= random_get_entropy();
+ if (arch_get_random_seed_long(&v) || arch_get_random_long(&v))
+ chacha20->key.u[i] ^= v;
+ }
+
+ for (i = 0; i < 3; i++) {
+ chacha20->nonce[i] ^= jiffies;
+ chacha20->nonce[i] ^= random_get_entropy();
+ if (arch_get_random_seed_long(&v) || arch_get_random_long(&v))
+ chacha20->nonce[i] ^= v;
+ }
+
+ lrng_chacha20_update(state, NULL, CHACHA_BLOCK_WORDS);
+ pr_info("ChaCha20 core initialized\n");
+}
+
+void __init lrng_cc20_init_state_boot(struct chacha20_state *state)
+{
+ struct chacha20_block *chacha20 = &state->block;
+ unsigned long v;
+ u32 i;
+
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) {
+ if (arch_get_random_seed_long_early(&v) ||
+ arch_get_random_long_early(&v))
+ chacha20->key.u[i] ^= v;
+ }
+
+ for (i = 0; i < 3; i++) {
+ if (arch_get_random_seed_long_early(&v) ||
+ arch_get_random_long_early(&v))
+ chacha20->nonce[i] ^= v;
+ }
+
+ lrng_chacha20_update(state, NULL, CHACHA_BLOCK_WORDS);
+}
+
+/*
+ * Allocation of the DRNG state
+ */
+static void *lrng_cc20_drng_alloc(u32 sec_strength)
+{
+ struct chacha20_state *state = NULL;
+
+ if (sec_strength > CHACHA_KEY_SIZE) {
+ pr_err("Security strength of ChaCha20 DRNG (%u bits) lower than requested by LRNG (%u bits)\n",
+ CHACHA_KEY_SIZE * 8, sec_strength * 8);
+ return ERR_PTR(-EINVAL);
+ }
+ if (sec_strength < CHACHA_KEY_SIZE)
+ pr_warn("Security strength of ChaCha20 DRNG (%u bits) higher than requested by LRNG (%u bits)\n",
+ CHACHA_KEY_SIZE * 8, sec_strength * 8);
+
+ state = kmalloc(sizeof(struct chacha20_state), GFP_KERNEL);
+ if (!state)
+ return ERR_PTR(-ENOMEM);
+ pr_debug("memory for ChaCha20 core allocated\n");
+
+ lrng_cc20_init_state(state);
+
+ return state;
+}
+
+static void lrng_cc20_drng_dealloc(void *drng)
+{
+ struct chacha20_state *chacha20_state = (struct chacha20_state *)drng;
+
+ if (drng == &chacha20) {
+ memzero_explicit(chacha20_state, sizeof(*chacha20_state));
+ pr_debug("static ChaCha20 core zeroized\n");
+ return;
+ }
+
+ pr_debug("ChaCha20 core zeroized and freed\n");
+ kzfree(chacha20_state);
+}
+
+/******************************* Hash Operation *******************************/
+
+#ifdef CONFIG_CRYPTO_LIB_SHA256
+
+static u32 lrng_cc20_hash_digestsize(void *hash)
+{
+ return SHA256_DIGEST_SIZE;
+}
+
+static int lrng_cc20_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest)
+{
+ struct sha256_state sctx;
+
+ sha256_init(&sctx);
+ sha256_update(&sctx, inbuf, inbuflen);
+ sha256_final(&sctx, digest);
+
+ /* Zeroization of sctx is performed by sha256_final */
+
+ return 0;
+}
+
+static const char *lrng_cc20_hash_name(void)
+{
+ const char *cc20_hash_name = "SHA-256";
+ return cc20_hash_name;
+}
+
+#else /* CONFIG_CRYPTO_LIB_SHA256 */
+
+/*
+ * If the SHA-256 support is not compiled, we fall back to SHA-1 that is always
+ * compiled and present in the kernel.
+ */
+static u32 lrng_cc20_hash_digestsize(void *hash)
+{
+ return (SHA1_DIGEST_WORDS * sizeof(u32));
+}
+
+static int lrng_cc20_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest)
+{
+ u32 i;
+ u32 workspace[SHA1_WORKSPACE_WORDS];
+
+ WARN_ON(inbuflen % (SHA1_WORKSPACE_WORDS * sizeof(u32)));
+
+ sha1_init((u32 *)digest);
+ for (i = 0; i < inbuflen; i += (SHA1_WORKSPACE_WORDS * sizeof(u32)))
+ sha1_transform((u32 *)digest, (inbuf + i), workspace);
+ memzero_explicit(workspace, sizeof(workspace));
+
+ return 0;
+}
+
+static const char *lrng_cc20_hash_name(void)
+{
+ const char *cc20_hash_name = "SHA-1";
+ return cc20_hash_name;
+}
+
+#endif /* CONFIG_CRYPTO_LIB_SHA256 */
+
+static void *lrng_cc20_hash_alloc(const u8 *key, u32 keylen)
+{
+ pr_info("Hash %s allocated\n", lrng_cc20_hash_name());
+ return NULL;
+}
+
+static void lrng_cc20_hash_dealloc(void *hash)
+{
+}
+
+static const char *lrng_cc20_drng_name(void)
+{
+ const char *cc20_drng_name = "ChaCha20 DRNG";
+ return cc20_drng_name;
+}
+
+const struct lrng_crypto_cb lrng_cc20_crypto_cb = {
+ .lrng_drng_name = lrng_cc20_drng_name,
+ .lrng_hash_name = lrng_cc20_hash_name,
+ .lrng_drng_alloc = lrng_cc20_drng_alloc,
+ .lrng_drng_dealloc = lrng_cc20_drng_dealloc,
+ .lrng_drng_seed_helper = lrng_cc20_drng_seed_helper,
+ .lrng_drng_generate_helper = lrng_cc20_drng_generate_helper,
+ .lrng_hash_alloc = lrng_cc20_hash_alloc,
+ .lrng_hash_dealloc = lrng_cc20_hash_dealloc,
+ .lrng_hash_digestsize = lrng_cc20_hash_digestsize,
+ .lrng_hash_buffer = lrng_cc20_hash_buffer,
+};
diff --git a/drivers/char/lrng/lrng_chacha20.h b/drivers/char/lrng/lrng_chacha20.h
new file mode 100644
index 000000000000..1533b2490964
--- /dev/null
+++ b/drivers/char/lrng/lrng_chacha20.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * LRNG ChaCha20 definitions
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#include <crypto/chacha.h>
+
+/* State according to RFC 7539 section 2.3 */
+struct chacha20_block {
+ u32 constants[4];
+ union {
+#define CHACHA_KEY_SIZE_WORDS (CHACHA_KEY_SIZE / sizeof(u32))
+ u32 u[CHACHA_KEY_SIZE_WORDS];
+ u8 b[CHACHA_KEY_SIZE];
+ } key __latent_entropy;
+ u32 counter;
+ u32 nonce[3] __latent_entropy;
+};
+
+static inline void lrng_cc20_init_rfc7539(struct chacha20_block *chacha20)
+{
+ /* String "expand 32-byte k" */
+ chacha20->constants[0] = 0x61707865;
+ chacha20->constants[1] = 0x3320646e;
+ chacha20->constants[2] = 0x79622d32;
+ chacha20->constants[3] = 0x6b206574;
+}
diff --git a/drivers/char/lrng/lrng_drng.c b/drivers/char/lrng/lrng_drng.c
new file mode 100644
index 000000000000..ac6e40794cfe
--- /dev/null
+++ b/drivers/char/lrng/lrng_drng.c
@@ -0,0 +1,409 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG DRNG processing
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/lrng.h>
+
+#include "lrng_internal.h"
+
+/*
+ * Maximum number of seconds between DRNG reseed intervals of the DRNG. Note,
+ * this is enforced with the next request of random numbers from the
+ * DRNG. Setting this value to zero implies a reseeding attempt before every
+ * generated random number.
+ */
+int lrng_drng_reseed_max_time = 600;
+
+static atomic_t lrng_avail = ATOMIC_INIT(0);
+
+DEFINE_MUTEX(lrng_crypto_cb_update);
+
+/* DRNG for /dev/urandom, getrandom(2), get_random_bytes */
+static struct lrng_drng lrng_drng_init = {
+ .drng = &chacha20,
+ .crypto_cb = &lrng_cc20_crypto_cb,
+ .lock = __MUTEX_INITIALIZER(lrng_drng_init.lock),
+ .spin_lock = __SPIN_LOCK_UNLOCKED(lrng_drng_init.spin_lock)
+};
+
+/*
+ * DRNG for get_random_bytes when called in atomic context. This
+ * DRNG will always use the ChaCha20 DRNG. It will never benefit from a
+ * DRNG switch like the "regular" DRNG. If there was no DRNG switch, the atomic
+ * DRNG is identical to the "regular" DRNG.
+ *
+ * The reason for having this is due to the fact that DRNGs other than
+ * the ChaCha20 DRNG may sleep.
+ */
+static struct lrng_drng lrng_drng_atomic = {
+ .drng = &chacha20,
+ .crypto_cb = &lrng_cc20_crypto_cb,
+ .spin_lock = __SPIN_LOCK_UNLOCKED(lrng_drng_atomic.spin_lock)
+};
+
+/********************************** Helper ************************************/
+
+bool lrng_get_available(void)
+{
+ return likely(atomic_read(&lrng_avail));
+}
+
+void lrng_set_available(void)
+{
+ atomic_set(&lrng_avail, 1);
+}
+
+struct lrng_drng *lrng_drng_init_instance(void)
+{
+ return &lrng_drng_init;
+}
+
+struct lrng_drng *lrng_drng_atomic_instance(void)
+{
+ return &lrng_drng_atomic;
+}
+
+void lrng_drng_reset(struct lrng_drng *drng)
+{
+ atomic_set(&drng->requests, LRNG_DRNG_RESEED_THRESH);
+ drng->last_seeded = jiffies;
+ drng->fully_seeded = false;
+ drng->force_reseed = true;
+ pr_debug("reset DRNG\n");
+}
+
+/* Initialize the default DRNG during boot */
+static void lrng_drngs_init_cc20(void)
+{
+ unsigned long flags = 0;
+
+ if (lrng_get_available())
+ return;
+
+ lrng_drng_lock(&lrng_drng_init, &flags);
+ if (lrng_get_available()) {
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+ return;
+ }
+
+ lrng_drng_reset(&lrng_drng_init);
+ lrng_cc20_init_state(&chacha20);
+ lrng_state_init_seed_work();
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+
+ lrng_drng_lock(&lrng_drng_atomic, &flags);
+ lrng_drng_reset(&lrng_drng_atomic);
+ /*
+ * We do not initialize the state of the atomic DRNG as it is identical
+ * to the DRNG at this point.
+ */
+ lrng_drng_unlock(&lrng_drng_atomic, &flags);
+
+ lrng_set_available();
+}
+
+/************************* Random Number Generation ***************************/
+
+/* Inject a data buffer into the DRNG */
+static void lrng_drng_inject(struct lrng_drng *drng,
+ const u8 *inbuf, u32 inbuflen)
+{
+ const char *drng_type = unlikely(drng == &lrng_drng_atomic) ?
+ "atomic" : "regular";
+ unsigned long flags = 0;
+
+ BUILD_BUG_ON(LRNG_DRNG_RESEED_THRESH > INT_MAX);
+ pr_debug("seeding %s DRNG with %u bytes\n", drng_type, inbuflen);
+ lrng_drng_lock(drng, &flags);
+ if (drng->crypto_cb->lrng_drng_seed_helper(drng->drng,
+ inbuf, inbuflen) < 0) {
+ pr_warn("seeding of %s DRNG failed\n", drng_type);
+ atomic_set(&drng->requests, 1);
+ } else {
+ pr_debug("%s DRNG stats since last seeding: %lu secs; generate calls: %d\n",
+ drng_type,
+ (time_after(jiffies, drng->last_seeded) ?
+ (jiffies - drng->last_seeded) : 0) / HZ,
+ (LRNG_DRNG_RESEED_THRESH -
+ atomic_read(&drng->requests)));
+ drng->last_seeded = jiffies;
+ atomic_set(&drng->requests, LRNG_DRNG_RESEED_THRESH);
+ drng->force_reseed = false;
+
+ if (drng->drng == lrng_drng_atomic.drng) {
+ lrng_drng_atomic.last_seeded = jiffies;
+ atomic_set(&lrng_drng_atomic.requests,
+ LRNG_DRNG_RESEED_THRESH);
+ lrng_drng_atomic.force_reseed = false;
+ }
+ }
+ lrng_drng_unlock(drng, &flags);
+}
+
+/*
+ * Perform the seeding of the DRNG with data from noise source
+ */
+static inline int _lrng_drng_seed(struct lrng_drng *drng)
+{
+ struct entropy_buf seedbuf __aligned(LRNG_KCAPI_ALIGN);
+ unsigned long flags = 0;
+ u32 total_entropy_bits;
+ int ret;
+
+ lrng_drng_lock(drng, &flags);
+ total_entropy_bits = lrng_fill_seed_buffer(drng->crypto_cb, drng->hash,
+ &seedbuf, 0);
+ lrng_drng_unlock(drng, &flags);
+
+ /* Allow the seeding operation to be called again */
+ lrng_pool_unlock();
+ lrng_init_ops(total_entropy_bits);
+ ret = total_entropy_bits >> 3;
+
+ lrng_drng_inject(drng, (u8 *)&seedbuf, sizeof(seedbuf));
+ memzero_explicit(&seedbuf, sizeof(seedbuf));
+
+ return ret;
+}
+
+static int lrng_drng_get(struct lrng_drng *drng, u8 *outbuf, u32 outbuflen);
+static void lrng_drng_seed(struct lrng_drng *drng)
+{
+ int ret = _lrng_drng_seed(drng);
+
+ if (ret >= LRNG_DRNG_SECURITY_STRENGTH_BYTES)
+ drng->fully_seeded = true;
+
+ BUILD_BUG_ON(LRNG_MIN_SEED_ENTROPY_BITS >
+ LRNG_DRNG_SECURITY_STRENGTH_BITS);
+
+ /*
+ * Reseed atomic DRNG from current DRNG,
+ *
+ * We can obtain random numbers from DRNG as the lock type
+ * chosen by lrng_drng_get is usable with the current caller.
+ */
+ if ((drng->drng != lrng_drng_atomic.drng) &&
+ (lrng_drng_atomic.force_reseed ||
+ atomic_read(&lrng_drng_atomic.requests) <= 0 ||
+ time_after(jiffies, lrng_drng_atomic.last_seeded +
+ lrng_drng_reseed_max_time * HZ))) {
+ u8 seedbuf[LRNG_DRNG_SECURITY_STRENGTH_BYTES]
+ __aligned(LRNG_KCAPI_ALIGN);
+
+ ret = lrng_drng_get(drng, seedbuf, sizeof(seedbuf));
+
+ if (ret < 0) {
+ pr_warn("Error generating random numbers for atomic DRNG: %d\n",
+ ret);
+ } else {
+ lrng_drng_inject(&lrng_drng_atomic, seedbuf, ret);
+ }
+ memzero_explicit(&seedbuf, sizeof(seedbuf));
+ }
+}
+
+static inline void _lrng_drng_seed_work(struct lrng_drng *drng, u32 node)
+{
+ pr_debug("reseed triggered by interrupt noise source for DRNG on NUMA node %d\n",
+ node);
+ lrng_drng_seed(drng);
+ if (drng->fully_seeded) {
+ /* Prevent reseed storm */
+ drng->last_seeded += node * 100 * HZ;
+ /* Prevent draining of pool on idle systems */
+ lrng_drng_reseed_max_time += 100;
+ }
+}
+
+/*
+ * DRNG reseed trigger: Kernel thread handler triggered by the schedule_work()
+ */
+void lrng_drng_seed_work(struct work_struct *dummy)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ u32 node;
+
+ if (lrng_drng) {
+ for_each_online_node(node) {
+ struct lrng_drng *drng = lrng_drng[node];
+
+ if (drng && !drng->fully_seeded) {
+ _lrng_drng_seed_work(drng, node);
+ goto out;
+ }
+ }
+ lrng_pool_all_numa_nodes_seeded();
+ } else {
+ if (!lrng_drng_init.fully_seeded)
+ _lrng_drng_seed_work(&lrng_drng_init, 0);
+ }
+
+out:
+ /* Allow the seeding operation to be called again */
+ lrng_pool_unlock();
+}
+
+/* Force all DRNGs to reseed before next generation */
+void lrng_drng_force_reseed(void)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ u32 node;
+
+ if (!lrng_drng) {
+ lrng_drng_init.force_reseed = true;
+ pr_debug("force reseed of initial DRNG\n");
+ return;
+ }
+ for_each_online_node(node) {
+ struct lrng_drng *drng = lrng_drng[node];
+
+ if (!drng)
+ continue;
+
+ drng->force_reseed = true;
+ pr_debug("force reseed of DRNG on node %u\n", node);
+ }
+ lrng_drng_atomic.force_reseed = true;
+}
+
+/**
+ * lrng_drng_get() - Get random data out of the DRNG which is reseeded
+ * frequently.
+ *
+ * @outbuf: buffer for storing random data
+ * @outbuflen: length of outbuf
+ *
+ * Return:
+ * * < 0 in error case (DRNG generation or update failed)
+ * * >=0 returning the returned number of bytes
+ */
+static int lrng_drng_get(struct lrng_drng *drng, u8 *outbuf, u32 outbuflen)
+{
+ unsigned long flags = 0;
+ u32 processed = 0;
+
+ if (!outbuf || !outbuflen)
+ return 0;
+
+ outbuflen = min_t(size_t, outbuflen, INT_MAX);
+
+ lrng_drngs_init_cc20();
+
+ while (outbuflen) {
+ u32 todo = min_t(u32, outbuflen, LRNG_DRNG_MAX_REQSIZE);
+ int ret;
+
+ /* All but the atomic DRNG are seeded during generation */
+ if (atomic_dec_and_test(&drng->requests) ||
+ drng->force_reseed ||
+ time_after(jiffies, drng->last_seeded +
+ lrng_drng_reseed_max_time * HZ)) {
+ if (likely(drng != &lrng_drng_atomic)) {
+ if (lrng_pool_trylock())
+ atomic_set(&drng->requests, 1);
+ else
+ lrng_drng_seed(drng);
+ }
+ }
+
+ lrng_drng_lock(drng, &flags);
+ ret = drng->crypto_cb->lrng_drng_generate_helper(
+ drng->drng, outbuf + processed, todo);
+ lrng_drng_unlock(drng, &flags);
+ if (ret <= 0) {
+ pr_warn("getting random data from DRNG failed (%d)\n",
+ ret);
+ return -EFAULT;
+ }
+ processed += ret;
+ outbuflen -= ret;
+ }
+
+ return processed;
+}
+
+int lrng_drng_get_atomic(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_drng_get(&lrng_drng_atomic, outbuf, outbuflen);
+}
+
+int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ struct lrng_drng *drng = &lrng_drng_init;
+ int node = numa_node_id();
+
+ might_sleep();
+
+ if (lrng_drng && lrng_drng[node] && lrng_drng[node]->fully_seeded)
+ drng = lrng_drng[node];
+
+ return lrng_drng_get(drng, outbuf, outbuflen);
+}
+
+/* Reset LRNG such that all existing entropy is gone */
+static void _lrng_reset(struct work_struct *work)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ unsigned long flags = 0;
+
+ if (!lrng_drng) {
+ lrng_drng_lock(&lrng_drng_init, &flags);
+ lrng_drng_reset(&lrng_drng_init);
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+ } else {
+ u32 node;
+
+ for_each_online_node(node) {
+ struct lrng_drng *drng = lrng_drng[node];
+
+ if (!drng)
+ continue;
+ lrng_drng_lock(drng, &flags);
+ lrng_drng_reset(drng);
+ lrng_drng_unlock(drng, &flags);
+ }
+ }
+ lrng_set_entropy_thresh(LRNG_INIT_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS);
+
+ lrng_reset_state();
+}
+
+static DECLARE_WORK(lrng_reset_work, _lrng_reset);
+
+void lrng_reset(void)
+{
+ schedule_work(&lrng_reset_work);
+}
+
+/***************************** Initialize LRNG *******************************/
+
+void __init lrng_drng_init_early(void)
+{
+ unsigned long flags = 0;
+
+ lrng_drng_lock(&lrng_drng_init, &flags);
+ lrng_cc20_init_state_boot(&chacha20);
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+}
+
+static int __init lrng_init(void)
+{
+ lrng_drngs_init_cc20();
+
+ lrng_drngs_numa_alloc();
+ return 0;
+}
+
+late_initcall(lrng_init);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Stephan Mueller <[email protected]>");
+MODULE_DESCRIPTION("Linux Random Number Generator");
diff --git a/drivers/char/lrng/lrng_interfaces.c b/drivers/char/lrng/lrng_interfaces.c
new file mode 100644
index 000000000000..d9c68679136d
--- /dev/null
+++ b/drivers/char/lrng/lrng_interfaces.c
@@ -0,0 +1,649 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG User and kernel space interfaces
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/freezer.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/hw_random.h>
+#include <linux/kthread.h>
+#include <linux/poll.h>
+#include <linux/preempt.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/timex.h>
+
+#include "lrng_internal.h"
+
+/*
+ * If the entropy count falls under this number of bits, then we
+ * should wake up processes which are selecting or polling on write
+ * access to /dev/random.
+ */
+u32 lrng_write_wakeup_bits = LRNG_WRITE_WAKEUP_ENTROPY;
+
+static LIST_HEAD(lrng_ready_list);
+static DEFINE_SPINLOCK(lrng_ready_list_lock);
+
+static DECLARE_WAIT_QUEUE_HEAD(lrng_write_wait);
+static DECLARE_WAIT_QUEUE_HEAD(lrng_init_wait);
+static struct fasync_struct *fasync;
+
+struct ctl_table random_table[];
+/********************************** Helper ***********************************/
+
+/* Is the DRNG seed level too low? */
+static inline bool lrng_need_entropy(void)
+{
+ return (lrng_avail_entropy() < lrng_write_wakeup_bits);
+}
+
+void lrng_writer_wakeup(void)
+{
+ if (lrng_need_entropy() && wq_has_sleeper(&lrng_write_wait)) {
+ wake_up_interruptible(&lrng_write_wait);
+ kill_fasync(&fasync, SIGIO, POLL_OUT);
+ }
+}
+
+void lrng_init_wakeup(void)
+{
+ wake_up_all(&lrng_init_wait);
+ kill_fasync(&fasync, SIGIO, POLL_IN);
+}
+
+/**
+ * lrng_process_ready_list() - Ping all kernel internal callers waiting until
+ * the DRNG is at least minimally seeded to inform that the DRNG reached that
+ * seed level.
+ *
+ * When the SP800-90B testing is enabled, the ping only happens if the SP800-90B
+ * startup health tests are completed. This implies that kernel internal
+ * callers always have an SP800-90B compliant noise source when being
+ * pinged.
+ */
+void lrng_process_ready_list(void)
+{
+ unsigned long flags;
+ struct random_ready_callback *rdy, *tmp;
+
+ if (!lrng_sp80090b_startup_complete())
+ return;
+
+ spin_lock_irqsave(&lrng_ready_list_lock, flags);
+ list_for_each_entry_safe(rdy, tmp, &lrng_ready_list, list) {
+ struct module *owner = rdy->owner;
+
+ list_del_init(&rdy->list);
+ rdy->func(rdy);
+ module_put(owner);
+ }
+ spin_unlock_irqrestore(&lrng_ready_list_lock, flags);
+}
+
+void lrng_debug_report_seedlevel(const char *name)
+{
+#ifdef CONFIG_WARN_ALL_UNSEEDED_RANDOM
+ static void *previous = NULL;
+ void *caller = (void *) _RET_IP_;
+
+ if (READ_ONCE(previous) == caller)
+ return;
+
+ if (!lrng_state_min_seeded())
+ pr_notice("%pS %s called without reaching mimimally seeded level (available entropy %u)\n",
+ caller, name, lrng_avail_entropy());
+
+ WRITE_ONCE(previous, caller);
+#endif
+}
+
+/************************ LRNG kernel input interfaces ************************/
+
+/**
+ * add_hwgenerator_randomness() - Interface for in-kernel drivers of true
+ * hardware RNGs.
+ *
+ * Those devices may produce endless random bits and will be throttled
+ * when our pool is full.
+ *
+ * @buffer: buffer holding the entropic data from HW noise sources to be used to
+ * insert into entropy pool.
+ * @count: length of buffer
+ * @entropy_bits: amount of entropy in buffer (value is in bits)
+ */
+void add_hwgenerator_randomness(const char *buffer, size_t count,
+ size_t entropy_bits)
+{
+ /*
+ * Suspend writing if we are fully loaded with entropy.
+ * We'll be woken up again once below lrng_write_wakeup_thresh,
+ * or when the calling thread is about to terminate.
+ */
+ wait_event_interruptible(lrng_write_wait,
+ lrng_need_entropy() ||
+ lrng_state_exseed_allow(lrng_noise_source_hw) ||
+ kthread_should_stop());
+ lrng_state_exseed_set(lrng_noise_source_hw, false);
+ lrng_pool_lfsr_nonaligned(buffer, count);
+ lrng_pool_add_entropy(entropy_bits);
+}
+EXPORT_SYMBOL_GPL(add_hwgenerator_randomness);
+
+/**
+ * add_bootloader_randomness() - Handle random seed passed by bootloader.
+ *
+ * If the seed is trustworthy, it would be regarded as hardware RNGs. Otherwise
+ * it would be regarded as device data.
+ * The decision is controlled by CONFIG_RANDOM_TRUST_BOOTLOADER.
+ *
+ * @buf: buffer holding the entropic data from HW noise sources to be used to
+ * insert into entropy pool.
+ * @size: length of buffer
+ */
+void add_bootloader_randomness(const void *buf, unsigned int size)
+{
+ if (IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER))
+ add_hwgenerator_randomness(buf, size, size * 8);
+ else
+ add_device_randomness(buf, size);
+}
+EXPORT_SYMBOL_GPL(add_bootloader_randomness);
+
+/*
+ * Callback for HID layer -- use the HID event values to stir the entropy pool
+ */
+void add_input_randomness(unsigned int type, unsigned int code,
+ unsigned int value)
+{
+ static unsigned char last_value;
+
+ /* ignore autorepeat and the like */
+ if (value == last_value)
+ return;
+
+ last_value = value;
+
+ lrng_pool_lfsr_u32((type << 4) ^ code ^ (code >> 4) ^ value);
+}
+EXPORT_SYMBOL_GPL(add_input_randomness);
+
+/**
+ * add_device_randomness() - Add device- or boot-specific data to the entropy
+ * pool to help initialize it.
+ *
+ * None of this adds any entropy; it is meant to avoid the problem of
+ * the entropy pool having similar initial state across largely
+ * identical devices.
+ *
+ * @buf: buffer holding the entropic data from HW noise sources to be used to
+ * insert into entropy pool.
+ * @size: length of buffer
+ */
+void add_device_randomness(const void *buf, unsigned int size)
+{
+ lrng_pool_lfsr_nonaligned((u8 *)buf, size);
+ lrng_pool_lfsr_u32(random_get_entropy());
+ lrng_pool_lfsr_u32(jiffies);
+}
+EXPORT_SYMBOL(add_device_randomness);
+
+#ifdef CONFIG_BLOCK
+void rand_initialize_disk(struct gendisk *disk) { }
+void add_disk_randomness(struct gendisk *disk) { }
+EXPORT_SYMBOL(add_disk_randomness);
+#endif
+
+/**
+ * del_random_ready_callback() - Delete a previously registered readiness
+ * callback function.
+ *
+ * @rdy: callback definition that was registered initially
+ */
+void del_random_ready_callback(struct random_ready_callback *rdy)
+{
+ unsigned long flags;
+ struct module *owner = NULL;
+
+ spin_lock_irqsave(&lrng_ready_list_lock, flags);
+ if (!list_empty(&rdy->list)) {
+ list_del_init(&rdy->list);
+ owner = rdy->owner;
+ }
+ spin_unlock_irqrestore(&lrng_ready_list_lock, flags);
+
+ module_put(owner);
+}
+EXPORT_SYMBOL(del_random_ready_callback);
+
+/**
+ * add_random_ready_callback() - Add a callback function that will be invoked
+ * when the DRNG is mimimally seeded.
+ *
+ * @rdy: callback definition to be invoked when the LRNG is seeded
+ *
+ * Return:
+ * * 0 if callback is successfully added
+ * * -EALREADY if pool is already initialised (callback not called)
+ * * -ENOENT if module for callback is not alive
+ */
+int add_random_ready_callback(struct random_ready_callback *rdy)
+{
+ struct module *owner;
+ unsigned long flags;
+ int err = -EALREADY;
+
+ if (likely(lrng_state_min_seeded()))
+ return err;
+
+ owner = rdy->owner;
+ if (!try_module_get(owner))
+ return -ENOENT;
+
+ spin_lock_irqsave(&lrng_ready_list_lock, flags);
+ if (lrng_state_min_seeded())
+ goto out;
+
+ owner = NULL;
+
+ list_add(&rdy->list, &lrng_ready_list);
+ err = 0;
+
+out:
+ spin_unlock_irqrestore(&lrng_ready_list_lock, flags);
+
+ module_put(owner);
+
+ return err;
+}
+EXPORT_SYMBOL(add_random_ready_callback);
+
+/*********************** LRNG kernel output interfaces ************************/
+
+/**
+ * get_random_bytes() - Provider of cryptographic strong random numbers for
+ * kernel-internal usage.
+ *
+ * This function is appropriate for all in-kernel use cases. However,
+ * it will always use the ChaCha20 DRNG.
+ *
+ * @buf: buffer to store the random bytes
+ * @nbytes: size of the buffer
+ */
+void get_random_bytes(void *buf, int nbytes)
+{
+ lrng_drng_get_atomic((u8 *)buf, (u32)nbytes);
+ lrng_debug_report_seedlevel("get_random_bytes");
+}
+EXPORT_SYMBOL(get_random_bytes);
+
+/**
+ * get_random_bytes_full() - Provider of cryptographic strong random numbers
+ * for kernel-internal usage.
+ *
+ * This function is appropriate only for non-atomic use cases as this
+ * function may sleep. Though, it provides access to the full functionality
+ * of LRNG including the switchable DRNG support, that may support other
+ * DRNGs such as the SP800-90A DRBG.
+ *
+ * @buf: buffer to store the random bytes
+ * @nbytes: size of the buffer
+ */
+void get_random_bytes_full(void *buf, int nbytes)
+{
+ lrng_drng_get_sleep((u8 *)buf, (u32)nbytes);
+ lrng_debug_report_seedlevel("get_random_bytes_full");
+}
+EXPORT_SYMBOL(get_random_bytes_full);
+
+/**
+ * wait_for_random_bytes() - Wait for the LRNG to be seeded and thus
+ * guaranteed to supply cryptographically secure random numbers.
+ *
+ * This applies to: the /dev/urandom device, the get_random_bytes function,
+ * and the get_random_{u32,u64,int,long} family of functions. Using any of
+ * these functions without first calling this function forfeits the guarantee
+ * of security.
+ *
+ * Return:
+ * * 0 if the LRNG has been seeded.
+ * * -ERESTARTSYS if the function was interrupted by a signal.
+ */
+int wait_for_random_bytes(void)
+{
+ if (likely(lrng_state_min_seeded()))
+ return 0;
+ return wait_event_interruptible(lrng_init_wait,
+ lrng_state_min_seeded());
+}
+EXPORT_SYMBOL(wait_for_random_bytes);
+
+/**
+ * get_random_bytes_arch() - This function will use the architecture-specific
+ * hardware random number generator if it is available.
+ *
+ * The arch-specific hw RNG will almost certainly be faster than what we can
+ * do in software, but it is impossible to verify that it is implemented
+ * securely (as opposed, to, say, the AES encryption of a sequence number using
+ * a key known by the NSA). So it's useful if we need the speed, but only if
+ * we're willing to trust the hardware manufacturer not to have put in a back
+ * door.
+ *
+ * @buf: buffer allocated by caller to store the random data in
+ * @nbytes: length of outbuf
+ *
+ * Return: number of bytes filled in.
+ */
+int __must_check get_random_bytes_arch(void *buf, int nbytes)
+{
+ u8 *p = buf;
+
+ while (nbytes) {
+ unsigned long v;
+ int chunk = min_t(int, nbytes, sizeof(unsigned long));
+
+ if (!arch_get_random_long(&v))
+ break;
+
+ memcpy(p, &v, chunk);
+ p += chunk;
+ nbytes -= chunk;
+ }
+
+ if (nbytes)
+ lrng_drng_get_atomic((u8 *)p, (u32)nbytes);
+
+ return nbytes;
+}
+EXPORT_SYMBOL(get_random_bytes_arch);
+
+/*
+ * Returns whether or not the LRNG has been seeded.
+ *
+ * Returns: true if the urandom pool has been seeded.
+ * false if the urandom pool has not been seeded.
+ */
+bool rng_is_initialized(void)
+{
+ return lrng_state_operational();
+}
+EXPORT_SYMBOL(rng_is_initialized);
+
+/************************ LRNG user output interfaces *************************/
+
+static ssize_t lrng_read_common(char __user *buf, size_t nbytes)
+{
+ ssize_t ret = 0;
+ u8 tmpbuf[LRNG_DRNG_BLOCKSIZE] __aligned(LRNG_KCAPI_ALIGN);
+ u8 *tmp_large = NULL, *tmp = tmpbuf;
+ u32 tmplen = sizeof(tmpbuf);
+
+ if (nbytes == 0)
+ return 0;
+
+ /*
+ * Satisfy large read requests -- as the common case are smaller
+ * request sizes, such as 16 or 32 bytes, avoid a kmalloc overhead for
+ * those by using the stack variable of tmpbuf.
+ */
+ if (!CONFIG_BASE_SMALL && (nbytes > sizeof(tmpbuf))) {
+ tmplen = min_t(u32, nbytes, LRNG_DRNG_MAX_REQSIZE);
+ tmp_large = kmalloc(tmplen + LRNG_KCAPI_ALIGN, GFP_KERNEL);
+ if (!tmp_large)
+ tmplen = sizeof(tmpbuf);
+ else
+ tmp = PTR_ALIGN(tmp_large, LRNG_KCAPI_ALIGN);
+ }
+
+ while (nbytes) {
+ u32 todo = min_t(u32, nbytes, tmplen);
+ int rc = 0;
+
+ /* Reschedule if we received a large request. */
+ if ((tmp_large) && need_resched()) {
+ if (signal_pending(current)) {
+ if (ret == 0)
+ ret = -ERESTARTSYS;
+ break;
+ }
+ schedule();
+ }
+
+ rc = lrng_drng_get_sleep(tmp, todo);
+ if (rc <= 0) {
+ if (rc < 0)
+ ret = rc;
+ break;
+ }
+ if (copy_to_user(buf, tmp, rc)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ nbytes -= rc;
+ buf += rc;
+ ret += rc;
+ }
+
+ /* Wipe data just returned from memory */
+ if (tmp_large)
+ kzfree(tmp_large);
+ else
+ memzero_explicit(tmpbuf, sizeof(tmpbuf));
+
+ return ret;
+}
+
+static ssize_t
+lrng_read_common_block(int nonblock, char __user *buf, size_t nbytes)
+{
+ if (nbytes == 0)
+ return 0;
+
+ if (unlikely(!lrng_state_operational())) {
+ int ret;
+
+ if (nonblock)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(lrng_init_wait,
+ lrng_state_operational());
+ if (unlikely(ret))
+ return ret;
+ }
+
+ return lrng_read_common(buf, nbytes);
+}
+
+static ssize_t lrng_drng_read_block(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ return lrng_read_common_block(file->f_flags & O_NONBLOCK, buf, nbytes);
+}
+
+static unsigned int lrng_random_poll(struct file *file, poll_table *wait)
+{
+ __poll_t mask;
+
+ poll_wait(file, &lrng_init_wait, wait);
+ poll_wait(file, &lrng_write_wait, wait);
+ mask = 0;
+ if (lrng_state_operational())
+ mask |= EPOLLIN | EPOLLRDNORM;
+ if (lrng_need_entropy() ||
+ lrng_state_exseed_allow(lrng_noise_source_user))
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ return mask;
+}
+
+static ssize_t lrng_drng_write_common(const char __user *buffer, size_t count,
+ u32 entropy_bits)
+{
+ ssize_t ret = 0;
+ u8 buf[64] __aligned(LRNG_KCAPI_ALIGN);
+ const char __user *p = buffer;
+ u32 orig_entropy_bits = entropy_bits;
+
+ if (!lrng_get_available())
+ return -EAGAIN;
+
+ count = min_t(size_t, count, INT_MAX);
+ while (count > 0) {
+ size_t bytes = min_t(size_t, count, sizeof(buf));
+ u32 ent = min_t(u32, bytes<<3, entropy_bits);
+
+ if (copy_from_user(&buf, p, bytes))
+ return -EFAULT;
+ /* Inject data into entropy pool */
+ lrng_pool_lfsr(buf, bytes);
+ lrng_pool_add_entropy(ent);
+
+ count -= bytes;
+ p += bytes;
+ ret += bytes;
+ entropy_bits -= ent;
+
+ cond_resched();
+ }
+
+ /* Force reseed of DRNG during next data request. */
+ if (!orig_entropy_bits)
+ lrng_drng_force_reseed();
+
+ return ret;
+}
+
+static ssize_t lrng_drng_read(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ if (!lrng_state_min_seeded())
+ pr_notice_ratelimited("%s - use of insufficiently seeded DRNG (%zu bytes read)\n",
+ current->comm, nbytes);
+ else if (!lrng_state_operational())
+ pr_debug_ratelimited("%s - use of not fully seeded DRNG (%zu bytes read)\n",
+ current->comm, nbytes);
+
+ return lrng_read_common(buf, nbytes);
+}
+
+static ssize_t lrng_drng_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ return lrng_drng_write_common(buffer, count, 0);
+}
+
+static long lrng_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+ int size, ent_count_bits;
+ int __user *p = (int __user *)arg;
+
+ switch (cmd) {
+ case RNDGETENTCNT:
+ ent_count_bits = lrng_avail_entropy();
+ if (put_user(ent_count_bits, p))
+ return -EFAULT;
+ return 0;
+ case RNDADDTOENTCNT:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ if (get_user(ent_count_bits, p))
+ return -EFAULT;
+ ent_count_bits = (int)lrng_avail_entropy() + ent_count_bits;
+ if (ent_count_bits < 0)
+ ent_count_bits = 0;
+ if (ent_count_bits > LRNG_POOL_SIZE_BITS)
+ ent_count_bits = LRNG_POOL_SIZE_BITS;
+ lrng_pool_set_entropy(ent_count_bits);
+ return 0;
+ case RNDADDENTROPY:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ if (get_user(ent_count_bits, p++))
+ return -EFAULT;
+ if (ent_count_bits < 0)
+ return -EINVAL;
+ if (get_user(size, p++))
+ return -EFAULT;
+ if (size < 0)
+ return -EINVAL;
+ lrng_state_exseed_set(lrng_noise_source_user, false);
+ /* there cannot be more entropy than data */
+ ent_count_bits = min(ent_count_bits, size<<3);
+ return lrng_drng_write_common((const char __user *)p, size,
+ ent_count_bits);
+ case RNDZAPENTCNT:
+ case RNDCLEARPOOL:
+ /* Clear the entropy pool counter. */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ lrng_pool_set_entropy(0);
+ return 0;
+ case RNDRESEEDCRNG:
+ /*
+ * We leave the capability check here since it is present
+ * in the upstream's RNG implementation. Yet, user space
+ * can trigger a reseed as easy as writing into /dev/random
+ * or /dev/urandom where no privilege is needed.
+ */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ /* Force a reseed of all DRNGs */
+ lrng_drng_force_reseed();
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int lrng_fasync(int fd, struct file *filp, int on)
+{
+ return fasync_helper(fd, filp, on, &fasync);
+}
+
+const struct file_operations random_fops = {
+ .read = lrng_drng_read_block,
+ .write = lrng_drng_write,
+ .poll = lrng_random_poll,
+ .unlocked_ioctl = lrng_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .fasync = lrng_fasync,
+ .llseek = noop_llseek,
+};
+
+const struct file_operations urandom_fops = {
+ .read = lrng_drng_read,
+ .write = lrng_drng_write,
+ .unlocked_ioctl = lrng_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .fasync = lrng_fasync,
+ .llseek = noop_llseek,
+};
+
+SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count,
+ unsigned int, flags)
+{
+ if (flags & ~(GRND_NONBLOCK|GRND_RANDOM|GRND_INSECURE))
+ return -EINVAL;
+
+ /*
+ * Requesting insecure and blocking randomness at the same time makes
+ * no sense.
+ */
+ if ((flags &
+ (GRND_INSECURE|GRND_RANDOM)) == (GRND_INSECURE|GRND_RANDOM))
+ return -EINVAL;
+
+ if (count > INT_MAX)
+ count = INT_MAX;
+
+ if (flags & GRND_INSECURE)
+ return lrng_drng_read(NULL, buf, count, NULL);
+
+ return lrng_read_common_block(flags & GRND_NONBLOCK, buf, count);
+}
diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h
new file mode 100644
index 000000000000..53c267115721
--- /dev/null
+++ b/drivers/char/lrng/lrng_internal.h
@@ -0,0 +1,336 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * Copyright (C) 2018 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#ifndef _LRNG_INTERNAL_H
+#define _LRNG_INTERNAL_H
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+
+/*************************** General LRNG parameter ***************************/
+
+/* Entropy pool parameter
+ *
+ * The LRNG_POOL_SIZE cannot be smaller than 64 bytes as the SHA-1 operation
+ * in lrng_chacha20.c requires multiples of 64 bytes
+ */
+#define LRNG_POOL_SIZE (16 << CONFIG_LRNG_POOL_SIZE)
+#define LRNG_POOL_WORD_BYTES (4) /* (sizeof(atomic_t)) */
+#define LRNG_POOL_SIZE_BYTES (LRNG_POOL_SIZE * LRNG_POOL_WORD_BYTES)
+#define LRNG_POOL_SIZE_BITS (LRNG_POOL_SIZE_BYTES * 8)
+#define LRNG_POOL_WORD_BITS (LRNG_POOL_WORD_BYTES * 8)
+
+/* Security strength of LRNG -- this must match DRNG security strength */
+#define LRNG_DRNG_SECURITY_STRENGTH_BYTES 32
+#define LRNG_DRNG_SECURITY_STRENGTH_BITS (LRNG_DRNG_SECURITY_STRENGTH_BYTES * 8)
+#define LRNG_DRNG_BLOCKSIZE 64 /* Maximum of DRNG block sizes */
+
+/*
+ * SP800-90A defines a maximum request size of 1<<16 bytes. The given value is
+ * considered a safer margin.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_DRNG_MAX_REQSIZE (1<<12)
+
+/*
+ * SP800-90A defines a maximum number of requests between reseeds of 2^48.
+ * The given value is considered a much safer margin, balancing requests for
+ * frequent reseeds with the need to conserve entropy. This value MUST NOT be
+ * larger than INT_MAX because it is used in an atomic_t.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_DRNG_RESEED_THRESH (1<<20)
+
+/*
+ * Number of interrupts to be recorded to assume that DRNG security strength
+ * bits of entropy are received.
+ * Note: a value below the DRNG security strength should not be defined as this
+ * may imply the DRNG can never be fully seeded in case other noise
+ * sources are unavailable.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_IRQ_ENTROPY_BITS LRNG_DRNG_SECURITY_STRENGTH_BITS
+
+/*
+ * Min required seed entropy is 128 bits covering the minimum entropy
+ * requirement of SP800-131A and the German BSI's TR02102.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_FULL_SEED_ENTROPY_BITS LRNG_DRNG_SECURITY_STRENGTH_BITS
+#define LRNG_MIN_SEED_ENTROPY_BITS 128
+#define LRNG_INIT_ENTROPY_BITS 32
+
+/*
+ * Amount of entropy that is lost with the conditioning functions of LFSR and
+ * hash_df as shown with the entropy analysis compliant to SP800-90B.
+ */
+#define LRNG_CONDITIONING_ENTROPY_LOSS 1
+
+/*
+ * Wakeup value
+ *
+ * This value is allowed to be changed.
+ */
+#if (LRNG_POOL_SIZE_BITS <= (LRNG_DRNG_SECURITY_STRENGTH_BITS * 2))
+# define LRNG_WRITE_WAKEUP_ENTROPY (LRNG_DRNG_SECURITY_STRENGTH_BITS + \
+ LRNG_CONDITIONING_ENTROPY_LOSS)
+#else
+# define LRNG_WRITE_WAKEUP_ENTROPY (LRNG_DRNG_SECURITY_STRENGTH_BITS * 2)
+#endif
+
+/*
+ * Oversampling factor of IRQ events to obtain
+ * LRNG_DRNG_SECURITY_STRENGTH_BYTES. This factor is used when a
+ * high-resolution time stamp is not available. In this case, jiffies and
+ * register contents are used to fill the entropy pool. These noise sources
+ * are much less entropic than the high-resolution timer. The entropy content
+ * is the entropy content assumed with LRNG_IRQ_ENTROPY_BITS divided by
+ * LRNG_IRQ_OVERSAMPLING_FACTOR.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_IRQ_OVERSAMPLING_FACTOR 10
+
+/*
+ * Alignmask which should cover all cipher implementations
+ * WARNING: If this is changed to a value larger than 8, manual
+ * alignment is necessary as older versions of GCC may not be capable
+ * of aligning stack variables at boundaries greater than 8.
+ * In this case, PTR_ALIGN must be used.
+ */
+#define LRNG_KCAPI_ALIGN 8
+
+/************************ Default DRNG implementation *************************/
+
+extern struct chacha20_state chacha20;
+extern const struct lrng_crypto_cb lrng_cc20_crypto_cb;
+void lrng_cc20_init_state(struct chacha20_state *state);
+void lrng_cc20_init_state_boot(struct chacha20_state *state);
+
+/********************************** /proc *************************************/
+
+static inline void lrng_pool_inc_numa_node(void) { }
+
+/****************************** LRNG interfaces *******************************/
+
+extern u32 lrng_write_wakeup_bits;
+extern int lrng_drng_reseed_max_time;
+
+void lrng_writer_wakeup(void);
+void lrng_init_wakeup(void);
+void lrng_debug_report_seedlevel(const char *name);
+void lrng_process_ready_list(void);
+
+/* External interface to use of the switchable DRBG inside the kernel */
+void get_random_bytes_full(void *buf, int nbytes);
+
+/************************** Entropy pool management ***************************/
+
+enum lrng_external_noise_source {
+ lrng_noise_source_hw,
+ lrng_noise_source_user
+};
+
+bool lrng_state_exseed_allow(enum lrng_external_noise_source source);
+void lrng_state_exseed_set(enum lrng_external_noise_source source, bool type);
+void lrng_state_init_seed_work(void);
+u32 lrng_avail_entropy(void);
+void lrng_set_entropy_thresh(u32 new);
+int lrng_pool_trylock(void);
+void lrng_pool_unlock(void);
+void lrng_reset_state(void);
+void lrng_pool_all_numa_nodes_seeded(void);
+bool lrng_state_min_seeded(void);
+bool lrng_state_fully_seeded(void);
+bool lrng_state_operational(void);
+bool lrng_pool_highres_timer(void);
+void lrng_pool_set_entropy(u32 entropy_bits);
+void lrng_pool_lfsr(const u8 *buf, u32 buflen);
+void lrng_pool_lfsr_nonaligned(const u8 *buf, u32 buflen);
+void lrng_pool_lfsr_u32(u32 value);
+void lrng_pool_add_irq(u32 irq_num);
+void lrng_pool_add_entropy(u32 entropy_bits);
+
+struct entropy_buf {
+ u8 a[LRNG_DRNG_SECURITY_STRENGTH_BYTES];
+ u8 b[LRNG_DRNG_SECURITY_STRENGTH_BYTES];
+ u8 c[LRNG_DRNG_SECURITY_STRENGTH_BYTES];
+ u32 now;
+};
+
+int lrng_fill_seed_buffer(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct entropy_buf *entropy_buf, u32 entropy_retain);
+void lrng_init_ops(u32 seed_bits);
+
+/************************** Jitter RNG Noise Source ***************************/
+
+#ifdef CONFIG_LRNG_JENT
+u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen);
+u32 lrng_jent_entropylevel(void);
+#else /* CONFIG_CRYPTO_JITTERENTROPY */
+static inline u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen) {return 0; }
+static inline u32 lrng_jent_entropylevel(void) { return 0; }
+#endif /* CONFIG_CRYPTO_JITTERENTROPY */
+
+/*************************** CPU-based Noise Source ***************************/
+
+u32 lrng_get_arch(u8 *outbuf);
+u32 lrng_slow_noise_req_entropy(u32 required_entropy_bits);
+
+/****************************** DRNG processing *******************************/
+
+/* Secondary DRNG state handle */
+struct lrng_drng {
+ void *drng; /* DRNG handle */
+ void *hash; /* Hash handle */
+ const struct lrng_crypto_cb *crypto_cb; /* Crypto callbacks */
+ atomic_t requests; /* Number of DRNG requests */
+ unsigned long last_seeded; /* Last time it was seeded */
+ bool fully_seeded; /* Is DRNG fully seeded? */
+ bool force_reseed; /* Force a reseed */
+ struct mutex lock;
+ spinlock_t spin_lock;
+};
+
+extern struct mutex lrng_crypto_cb_update;
+
+struct lrng_drng *lrng_drng_init_instance(void);
+struct lrng_drng *lrng_drng_atomic_instance(void);
+
+static __always_inline bool lrng_drng_is_atomic(struct lrng_drng *drng)
+{
+ return (drng->drng == lrng_drng_atomic_instance()->drng);
+}
+
+/* Lock the DRNG */
+static __always_inline void lrng_drng_lock(struct lrng_drng *drng,
+ unsigned long *flags)
+{
+ /* Use spin lock in case the atomic DRNG context is used */
+ if (lrng_drng_is_atomic(drng)) {
+ spin_lock_irqsave(&drng->spin_lock, *flags);
+
+ /*
+ * In case a lock transition happened while we were spinning,
+ * catch this case and use the new lock type.
+ */
+ if (!lrng_drng_is_atomic(drng)) {
+ spin_unlock_irqrestore(&drng->spin_lock, *flags);
+ mutex_lock(&drng->lock);
+ }
+ } else {
+ mutex_lock(&drng->lock);
+ }
+}
+
+/* Unlock the DRNG */
+static __always_inline void lrng_drng_unlock(struct lrng_drng *drng,
+ unsigned long *flags)
+{
+ if (lrng_drng_is_atomic(drng))
+ spin_unlock_irqrestore(&drng->spin_lock, *flags);
+ else
+ mutex_unlock(&drng->lock);
+}
+
+void lrng_drng_init_early(void);
+bool lrng_get_available(void);
+void lrng_set_available(void);
+void lrng_drng_reset(struct lrng_drng *drng);
+int lrng_drng_get_atomic(u8 *outbuf, u32 outbuflen);
+int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen);
+void lrng_drng_force_reseed(void);
+void lrng_drng_seed_work(struct work_struct *dummy);
+
+static inline struct lrng_drng **lrng_drng_instances(void) { return NULL; }
+static inline void lrng_drngs_numa_alloc(void) { return; }
+
+/************************** Health Test linking code **************************/
+
+enum lrng_health_res {
+ lrng_health_pass, /* Health test passes on time stamp */
+ lrng_health_fail_use, /* Time stamp unhealthy, but mix in */
+ lrng_health_fail_drop /* Time stamp unhealthy, drop it */
+};
+
+#ifdef CONFIG_LRNG_HEALTH_TESTS
+bool lrng_sp80090b_startup_complete(void);
+bool lrng_sp80090b_compliant(void);
+
+enum lrng_health_res lrng_health_test(u32 now_time);
+void lrng_health_disable(void);
+
+void lrng_reset(void);
+#else /* CONFIG_LRNG_HEALTH_TESTS */
+static inline bool lrng_sp80090b_startup_complete(void) { return true; }
+static inline bool lrng_sp80090b_compliant(void) { return false; }
+
+static inline enum lrng_health_res
+lrng_health_test(u32 now_time) { return lrng_health_pass; }
+static inline void lrng_health_disable(void) { }
+#endif /* CONFIG_LRNG_HEALTH_TESTS */
+
+/****************************** Helper code ***********************************/
+
+static inline u32 atomic_read_u32(atomic_t *v)
+{
+ return (u32)atomic_read(v);
+}
+
+/*************************** Auxiliary functions ******************************/
+
+void invalidate_batched_entropy(void);
+
+/***************************** Testing code ***********************************/
+
+#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY
+bool lrng_raw_hires_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_HIRES_ENTROPY */
+static inline bool lrng_raw_hires_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_HIRES_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY
+bool lrng_raw_jiffies_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */
+static inline bool lrng_raw_jiffies_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY
+bool lrng_raw_irq_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_IRQ_ENTROPY */
+static inline bool lrng_raw_irq_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_IRQ_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY
+bool lrng_raw_irqflags_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */
+static inline bool lrng_raw_irqflags_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY
+bool lrng_raw_retip_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_RETIP_ENTROPY */
+static inline bool lrng_raw_retip_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_RETIP_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_ARRAY
+bool lrng_raw_array_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_ARRAY */
+static inline bool lrng_raw_array_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_ARRAY */
+
+#ifdef CONFIG_LRNG_IRQ_PERF
+bool lrng_perf_time(u32 start);
+#else /* CONFIG_LRNG_IRQ_PERF */
+static inline bool lrng_perf_time(u32 start) { return false; }
+#endif /*CONFIG_LRNG_IRQ_PERF */
+
+#endif /* _LRNG_INTERNAL_H */
diff --git a/drivers/char/lrng/lrng_lfsr.h b/drivers/char/lrng/lrng_lfsr.h
new file mode 100644
index 000000000000..978ba97107e4
--- /dev/null
+++ b/drivers/char/lrng/lrng_lfsr.h
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * LRNG Linear Feedback Shift Register
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+/* Status information about IRQ noise source */
+struct lrng_irq_info {
+ atomic_t num_events; /* Number of healthy IRQs since last read */
+ atomic_t num_events_thresh; /* Reseed threshold */
+ atomic_t reseed_in_progress; /* Flag for on executing reseed */
+ bool irq_highres_timer; /* Is high-resolution timer available? */
+ u32 irq_entropy_bits; /* LRNG_IRQ_ENTROPY_BITS? */
+};
+
+/*
+ * This is the entropy pool used by the slow noise source. Its size should
+ * be at least as large as LRNG_DRNG_SECURITY_STRENGTH_BITS.
+ *
+ * The pool array is aligned to 8 bytes to comfort the kernel crypto API cipher
+ * implementations of the hash functions used to read the pool: for some
+ * accelerated implementations, we need an alignment to avoid a realignment
+ * which involves memcpy(). The alignment to 8 bytes should satisfy all crypto
+ * implementations.
+ *
+ * LRNG_POOL_SIZE is allowed to be changed only if the taps of the polynomial
+ * used for the LFSR are changed as well. The size must be in powers of 2 due
+ * to the mask handling in lrng_pool_lfsr_u32 which uses AND instead of modulo.
+ */
+struct lrng_pool {
+ union {
+ struct {
+ /*
+ * hash_df implementation: counter, requested_bits and
+ * pool form a linear buffer that is used in the
+ * hash_df function specified in SP800-90A section
+ * 10.3.1
+ */
+ unsigned char counter;
+ __be32 requested_bits;
+
+ /* Pool */
+ atomic_t pool[LRNG_POOL_SIZE] __latent_entropy;
+ /* Ptr into pool for next IRQ word injection */
+ atomic_t pool_ptr;
+ /* rotate for LFSR */
+ atomic_t input_rotate;
+ /* All NUMA DRNGs seeded? */
+ bool all_online_numa_node_seeded;
+ /* IRQ noise source status info */
+ struct lrng_irq_info irq_info;
+ /* Serialize read of entropy pool */
+ spinlock_t lock;
+ };
+ /*
+ * Static SHA-1 implementation in lrng_cc20_hash_buffer
+ * processes data 64-byte-wise. Hence, ensure proper size
+ * of LRNG entropy pool data structure.
+ */
+ u8 hash_input_buf[LRNG_POOL_SIZE_BYTES + 64];
+ };
+};
+
+/*
+ * Implement a (modified) twisted Generalized Feedback Shift Register. (See M.
+ * Matsumoto & Y. Kurita, 1992. Twisted GFSR generators. ACM Transactions on
+ * Modeling and Computer Simulation 2(3):179-194. Also see M. Matsumoto & Y.
+ * Kurita, 1994. Twisted GFSR generators II. ACM Transactions on Modeling and
+ * Computer Simulation 4:254-266).
+ */
+static u32 const lrng_twist_table[8] = {
+ 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
+ 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
+
+/*
+ * The polynomials for the LFSR are taken from the document "Table of Linear
+ * Feedback Shift Registers" by Roy Ward, Tim Molteno, October 26, 2007.
+ * The first polynomial is from "Primitive Binary Polynomials" by Wayne
+ * Stahnke (1973) and is primitive as well as irreducible.
+ *
+ * Note, the tap values are smaller by one compared to the documentation because
+ * they are used as an index into an array where the index starts by zero.
+ *
+ * All polynomials were also checked to be primitive and irreducible with magma
+ * which ensures that the key property of the LFSR providing a compression
+ * function for entropy is guaranteed.
+ */
+static u32 const lrng_lfsr_polynomial[][4] = {
+ { 15, 13, 12, 10 }, /* 16 words */
+ { 31, 29, 25, 24 }, /* 32 words */
+ { 63, 62, 60, 59 }, /* 64 words */
+ { 127, 28, 26, 1 }, /* 128 words by Stahnke */
+ { 255, 253, 250, 245 }, /* 256 words */
+ { 511, 509, 506, 503 }, /* 512 words */
+ { 1023, 1014, 1001, 1000 }, /* 1024 words */
+ { 2047, 2034, 2033, 2028 }, /* 2048 words */
+ { 4095, 4094, 4080, 4068 }, /* 4096 words */
+};
+
+static inline void _lrng_pool_lfsr_u32(struct lrng_pool *pool, u32 value)
+{
+ /*
+ * Process the LFSR by altering not adjacent words but rather
+ * more spaced apart words. Using a prime number ensures that all words
+ * are processed evenly. As some the LFSR polynomials taps are close
+ * together, processing adjacent words with the LSFR taps may be
+ * inappropriate as the data just mixed-in at these taps may be not
+ * independent from the current data to be mixed in.
+ */
+ u32 ptr = (u32)atomic_add_return_relaxed(67, &pool->pool_ptr) &
+ (LRNG_POOL_SIZE - 1);
+ /*
+ * Add 7 bits of rotation to the pool. At the beginning of the
+ * pool, add an extra 7 bits rotation, so that successive passes
+ * spread the input bits across the pool evenly.
+ *
+ * Note, there is a race between getting ptr and calculating
+ * input_rotate when ptr is obtained on two or more CPUs at the
+ * same time. This race is irrelevant as it may only come into effect
+ * if 3 or more CPUs race at the same time which is very unlikely. If
+ * the race happens, it applies to one event only. As this rolling
+ * supports the LFSR without being strictly needed, we accept this
+ * race.
+ */
+ u32 input_rotate = (u32)atomic_add_return_relaxed((ptr ? 7 : 14),
+ &pool->input_rotate) & 31;
+ u32 word = rol32(value, input_rotate);
+
+ BUILD_BUG_ON(LRNG_POOL_WORD_BYTES != sizeof(pool->pool[0]));
+ BUILD_BUG_ON(LRNG_POOL_SIZE - 1 !=
+ lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][0]);
+ word ^= atomic_read_u32(&pool->pool[ptr]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][0]) &
+ (LRNG_POOL_SIZE - 1)]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][1]) &
+ (LRNG_POOL_SIZE - 1)]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][2]) &
+ (LRNG_POOL_SIZE - 1)]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][3]) &
+ (LRNG_POOL_SIZE - 1)]);
+
+ word = (word >> 3) ^ lrng_twist_table[word & 7];
+ atomic_set(&pool->pool[ptr], word);
+}
+
+u32 __lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct lrng_pool *pool, u8 *outbuf, u32 requested_bits);
diff --git a/drivers/char/lrng/lrng_pool.c b/drivers/char/lrng/lrng_pool.c
new file mode 100644
index 000000000000..0d4111ce7bc2
--- /dev/null
+++ b/drivers/char/lrng/lrng_pool.c
@@ -0,0 +1,589 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Entropy pool management
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <asm/irq_regs.h>
+#include <linux/lrng.h>
+#include <linux/percpu.h>
+#include <linux/random.h>
+#include <linux/utsname.h>
+#include <linux/workqueue.h>
+
+#include "lrng_internal.h"
+#include "lrng_lfsr.h"
+
+struct lrng_state {
+ bool lrng_operational; /* Is DRNG operational? */
+ bool lrng_fully_seeded; /* Is DRNG fully seeded? */
+ bool lrng_min_seeded; /* Is DRNG minimally seeded? */
+
+ /*
+ * To ensure that external entropy providers cannot dominate the
+ * internal noise sources but yet cannot be dominated by internal
+ * noise sources, the following booleans are intended to allow
+ * external to provide seed once when a DRNG reseed occurs. This
+ * triggering of external noise source is performed even when the
+ * entropy pool has sufficient entropy.
+ */
+ bool lrng_seed_hw; /* Allow HW to provide seed */
+ bool lrng_seed_user; /* Allow user space to provide seed */
+
+ struct work_struct lrng_seed_work; /* (re)seed work queue */
+};
+
+static struct lrng_pool lrng_pool __aligned(LRNG_KCAPI_ALIGN) = {
+ .irq_info = {
+ .irq_entropy_bits = LRNG_IRQ_ENTROPY_BITS,
+ .num_events_thresh = ATOMIC_INIT(LRNG_INIT_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS),
+ /* Sample IRQ pointer data at least during boot */
+ .irq_highres_timer = false },
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_pool.lock)
+};
+
+static struct lrng_state lrng_state = { false, false, false, true, true };
+
+/********************************** Helper ***********************************/
+
+/* External entropy provider is allowed to provide seed data */
+bool lrng_state_exseed_allow(enum lrng_external_noise_source source)
+{
+ if (source == lrng_noise_source_hw)
+ return lrng_state.lrng_seed_hw;
+ return lrng_state.lrng_seed_user;
+}
+
+/* Enable / disable external entropy provider to furnish seed */
+void lrng_state_exseed_set(enum lrng_external_noise_source source, bool type)
+{
+ if (source == lrng_noise_source_hw)
+ lrng_state.lrng_seed_hw = type;
+ else
+ lrng_state.lrng_seed_user = type;
+}
+
+static inline void lrng_state_exseed_allow_all(void)
+{
+ lrng_state_exseed_set(lrng_noise_source_hw, true);
+ lrng_state_exseed_set(lrng_noise_source_user, true);
+}
+
+void lrng_state_init_seed_work(void)
+{
+ INIT_WORK(&lrng_state.lrng_seed_work, lrng_drng_seed_work);
+}
+
+static inline u32 lrng_entropy_to_data(u32 entropy_bits)
+{
+ return ((entropy_bits * lrng_pool.irq_info.irq_entropy_bits) /
+ LRNG_DRNG_SECURITY_STRENGTH_BITS);
+}
+
+static inline u32 lrng_data_to_entropy(u32 irqnum)
+{
+ return ((irqnum * LRNG_DRNG_SECURITY_STRENGTH_BITS) /
+ lrng_pool.irq_info.irq_entropy_bits);
+}
+
+u32 lrng_avail_entropy(void)
+{
+ return min_t(u32, LRNG_POOL_SIZE_BITS, lrng_data_to_entropy(
+ atomic_read_u32(&lrng_pool.irq_info.num_events)));
+}
+
+void lrng_set_entropy_thresh(u32 new)
+{
+ atomic_set(&lrng_pool.irq_info.num_events_thresh,
+ lrng_entropy_to_data(new));
+}
+
+/*
+ * Reading of the LRNG pool is only allowed by one caller. The reading is
+ * only performed to (re)seed DRNGs. Thus, if this "lock" is already taken,
+ * the reseeding operation is in progress. The caller is not intended to wait
+ * but continue with its other operation.
+ */
+int lrng_pool_trylock(void)
+{
+ return atomic_cmpxchg(&lrng_pool.irq_info.reseed_in_progress, 0, 1);
+}
+
+void lrng_pool_unlock(void)
+{
+ atomic_set(&lrng_pool.irq_info.reseed_in_progress, 0);
+}
+
+void lrng_reset_state(void)
+{
+ struct lrng_irq_info *irq_info = &lrng_pool.irq_info;
+
+ atomic_set(&irq_info->num_events, 0);
+ lrng_state.lrng_operational = false;
+ lrng_state.lrng_fully_seeded = false;
+ lrng_state.lrng_min_seeded = false;
+ lrng_pool.all_online_numa_node_seeded = false;
+ pr_debug("reset LRNG\n");
+}
+
+void lrng_pool_all_numa_nodes_seeded(void)
+{
+ lrng_pool.all_online_numa_node_seeded = true;
+}
+
+bool lrng_state_min_seeded(void)
+{
+ return lrng_state.lrng_min_seeded;
+}
+
+bool lrng_state_fully_seeded(void)
+{
+ return lrng_state.lrng_fully_seeded;
+}
+
+bool lrng_state_operational(void)
+{
+ return lrng_state.lrng_operational;
+}
+
+bool lrng_pool_highres_timer(void)
+{
+ return lrng_pool.irq_info.irq_highres_timer;
+}
+
+void lrng_pool_set_entropy(u32 entropy_bits)
+{
+ atomic_set(&lrng_pool.irq_info.num_events,
+ lrng_entropy_to_data(entropy_bits));
+}
+
+static void lrng_pool_configure(bool highres_timer, u32 irq_entropy_bits)
+{
+ struct lrng_irq_info *irq_info = &lrng_pool.irq_info;
+
+ irq_info->irq_highres_timer = highres_timer;
+ if (irq_info->irq_entropy_bits != irq_entropy_bits) {
+ irq_info->irq_entropy_bits = irq_entropy_bits;
+ /* Reset the threshold based on new oversampling factor. */
+ lrng_set_entropy_thresh(atomic_read_u32(
+ &irq_info->num_events_thresh));
+ }
+}
+
+static int __init lrng_init_time_source(void)
+{
+ if (random_get_entropy() || random_get_entropy()) {
+ /*
+ * As the highres timer is identified here, previous interrupts
+ * obtained during boot time are treated like a lowres-timer
+ * would have been present.
+ */
+ lrng_pool_configure(true, LRNG_IRQ_ENTROPY_BITS);
+ } else {
+ lrng_health_disable();
+ lrng_pool_configure(false, LRNG_IRQ_ENTROPY_BITS *
+ LRNG_IRQ_OVERSAMPLING_FACTOR);
+ pr_warn("operating without high-resolution timer and applying IRQ oversampling factor %u\n",
+ LRNG_IRQ_OVERSAMPLING_FACTOR);
+ }
+
+ return 0;
+}
+
+core_initcall(lrng_init_time_source);
+
+/* invoke function with buffer aligned to 4 bytes */
+void lrng_pool_lfsr(const u8 *buf, u32 buflen)
+{
+ u32 *p_buf = (u32 *)buf;
+
+ for (; buflen >= 4; buflen -= 4)
+ lrng_pool_lfsr_u32(*p_buf++);
+
+ buf = (u8 *)p_buf;
+ while (buflen--)
+ lrng_pool_lfsr_u32(*buf++);
+}
+
+void lrng_pool_lfsr_nonaligned(const u8 *buf, u32 buflen)
+{
+ while (buflen) {
+ if (!((unsigned long)buf & (sizeof(u32) - 1))) {
+ lrng_pool_lfsr(buf, buflen);
+ return;
+ }
+
+ lrng_pool_lfsr_u32(*buf++);
+ buflen--;
+ }
+}
+
+/**************************** Interrupt processing ****************************/
+
+/*
+ * Hot code path - inject data into entropy pool using LFSR
+ */
+void lrng_pool_lfsr_u32(u32 value)
+{
+ _lrng_pool_lfsr_u32(&lrng_pool, value);
+}
+
+/*
+ * Hot code path - mix data into entropy pool
+ */
+void lrng_pool_add_irq(u32 irq_num)
+{
+ struct lrng_irq_info *irq_info = &lrng_pool.irq_info;
+
+ atomic_add(irq_num, &irq_info->num_events);
+
+ /*
+ * Once all DRNGs are fully seeded, the interrupt noise
+ * sources will not trigger any reseeding any more.
+ */
+ if (likely(lrng_pool.all_online_numa_node_seeded))
+ return;
+
+ /* Only try to reseed if the DRNG is alive. */
+ if (!lrng_get_available())
+ return;
+
+ /* Only trigger the DRNG reseed if we have collected enough IRQs. */
+ if (atomic_read_u32(&lrng_pool.irq_info.num_events) <
+ atomic_read_u32(&lrng_pool.irq_info.num_events_thresh))
+ return;
+
+ /* Ensure that the seeding only occurs once at any given time. */
+ if (lrng_pool_trylock())
+ return;
+
+ /* Seed the DRNG with IRQ noise. */
+ schedule_work(&lrng_state.lrng_seed_work);
+}
+
+void lrng_pool_add_entropy(u32 entropy_bits)
+{
+ lrng_pool_add_irq(lrng_entropy_to_data(entropy_bits));
+}
+
+/*
+ * Generate a hashed output of pool using the SP800-90A section 10.3.1 hash_df
+ * function
+ */
+u32 __lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct lrng_pool *pool, u8 *outbuf, u32 requested_bits)
+{
+ u32 digestsize, requested_bytes = requested_bits >> 3,
+ generated_bytes = 0;
+ u8 digest[64] __aligned(LRNG_KCAPI_ALIGN);
+
+ digestsize = crypto_cb->lrng_hash_digestsize(hash);
+ if (digestsize > sizeof(digest)) {
+ pr_err("Digest buffer too small\n");
+ return 0;
+ }
+
+ pool->counter = 1;
+ pool->requested_bits = cpu_to_be32(requested_bytes << 3);
+
+ while (requested_bytes) {
+ u32 tocopy = min_t(u32, requested_bytes, digestsize);
+
+ /* The counter must not wrap */
+ if (pool->counter == 0)
+ goto out;
+
+ if (crypto_cb->lrng_hash_buffer(hash, (u8 *)pool,
+ LRNG_POOL_SIZE_BYTES + 64,
+ digest))
+ goto out;
+
+ /* Copy the data out to the caller */
+ memcpy(outbuf + generated_bytes, digest, tocopy);
+ requested_bytes -= tocopy;
+ generated_bytes += tocopy;
+ pool->counter++;
+ }
+
+out:
+ /* Mix read data back into pool for backtracking resistance */
+ if (generated_bytes)
+ lrng_pool_lfsr(outbuf, generated_bytes);
+ memzero_explicit(digest, digestsize);
+ return (generated_bytes<<3);
+}
+
+static inline u32 lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb,
+ void *hash, u8 *outbuf, u32 requested_bits)
+{
+ return __lrng_pool_hash_df(crypto_cb, hash, &lrng_pool, outbuf,
+ requested_bits);
+}
+
+/**
+ * lrng_get_pool() - Read the entropy pool out for use.
+ *
+ * This function handles the translation from the number of received interrupts
+ * into an entropy statement. The conversion depends on LRNG_IRQ_ENTROPY_BITS
+ * which defines how many interrupts must be received to obtain 256 bits of
+ * entropy. With this value, the function lrng_data_to_entropy converts a given
+ * data size (received interrupts, requested amount of data, etc.) into an
+ * entropy statement. lrng_entropy_to_data does the reverse.
+ *
+ * Both functions are agnostic about the type of data: when the number of
+ * interrupts is processed by these functions, the resulting entropy value is in
+ * bits as we assume the entropy of interrupts is measured in bits. When data is
+ * processed, the entropy value is in bytes as the data is measured in bytes.
+ *
+ * @outbuf: buffer to store data in with size LRNG_DRNG_SECURITY_STRENGTH_BYTES
+ * @requested_entropy_bits: requested bits of entropy -- the function will
+ * return at least this amount of entropy if available
+ * @entropy_retain: amount of entropy in bits that should be left in the pool
+ *
+ * Return: estimated entropy from the IRQs that was obtained
+ */
+static u32 lrng_get_pool(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ u8 *outbuf, u32 requested_entropy_bits,
+ u32 entropy_retain)
+{
+ struct lrng_pool *pool = &lrng_pool;
+ struct lrng_state *state = &lrng_state;
+ struct lrng_irq_info *irq_info = &pool->irq_info;
+ unsigned long flags;
+
+ u32 irq_num_events_used, irq_num_events, avail_entropy_bits;
+
+ /* This get_pool operation must only be called once at a given time! */
+ spin_lock_irqsave(&pool->lock, flags);
+
+ /* How many unused interrupts are in entropy pool? */
+ irq_num_events = atomic_read_u32(&irq_info->num_events);
+ /* Convert available interrupts into entropy statement */
+ avail_entropy_bits = lrng_data_to_entropy(irq_num_events);
+
+ /* Cap available entropy to pool size */
+ avail_entropy_bits =
+ min_t(u32, avail_entropy_bits, LRNG_POOL_SIZE_BITS);
+
+ /* How much entropy we need to and can we use? */
+ if (unlikely(!state->lrng_fully_seeded)) {
+ /*
+ * During boot time, we read 256 bits data with
+ * avail_entropy_bits entropy. In case our conservative
+ * entropy estimate underestimates the available entropy
+ * we can transport as much available entropy as
+ * possible. The entropy pool does not operate compliant to
+ * the German AIS 21/31 NTG.1 yet.
+ */
+ requested_entropy_bits =
+ LRNG_DRNG_SECURITY_STRENGTH_BITS;
+ } else {
+ /* Provide all entropy above retaining level */
+ if (avail_entropy_bits < entropy_retain) {
+ requested_entropy_bits = 0;
+ goto out;
+ }
+ avail_entropy_bits -= entropy_retain;
+ requested_entropy_bits = min_t(u32, avail_entropy_bits,
+ requested_entropy_bits);
+ }
+
+ /* Hash is a compression function: we generate entropy amount of data */
+ requested_entropy_bits = round_down(requested_entropy_bits, 8);
+
+ requested_entropy_bits = lrng_pool_hash_df(crypto_cb, hash, outbuf,
+ requested_entropy_bits);
+
+ /* Boot time: After getting the full buffer adjust the entropy value. */
+ requested_entropy_bits = min_t(u32, avail_entropy_bits,
+ requested_entropy_bits);
+
+out:
+ /* Convert used entropy into interrupt number for subtraction */
+ irq_num_events_used = lrng_entropy_to_data(requested_entropy_bits);
+
+ /*
+ * The hash_df operation entropy assessment shows that the output
+ * entropy is one bit smaller than the input entropy. Therefore we
+ * account for this one bit of entropy here: if we have sufficient
+ * entropy in the LFSR, we say we used one bit of entropy more.
+ * Otherwise we reduce the amount of entropy we say we generated with
+ * the hash_df.
+ */
+ if (irq_num_events_used) {
+ if ((irq_num_events_used + LRNG_CONDITIONING_ENTROPY_LOSS) <=
+ lrng_entropy_to_data(avail_entropy_bits)) {
+ irq_num_events_used += LRNG_CONDITIONING_ENTROPY_LOSS;
+ } else {
+ if (unlikely(requested_entropy_bits <
+ LRNG_CONDITIONING_ENTROPY_LOSS))
+ requested_entropy_bits = 0;
+ else
+ requested_entropy_bits -=
+ LRNG_CONDITIONING_ENTROPY_LOSS;
+ }
+ }
+
+ /*
+ * New events might have arrived in the meanwhile and we don't
+ * want to throw them away unconditionally. On the other hand,
+ * these new events might have been mixed in before
+ * lrng_hash_df_pool() had been able to draw any entropy
+ * from the pool and thus, the pool capacity might have been
+ * exceeded at some point. Note that in theory, some events
+ * might get lost inbetween the atomic_read() and
+ * atomic_set() below. But that's fine, because it's no real
+ * concern while code preventing this would come at the cost of
+ * additional complexity. Likewise, some events which arrived
+ * after full or partial completion of the __lrng_hash_df_pool()
+ * above might get unnecessarily thrown away by the min()
+ * operation below; the same argument applies there.
+ */
+ irq_num_events = atomic_read_u32(&irq_info->num_events);
+ irq_num_events = min_t(u32, irq_num_events,
+ lrng_entropy_to_data(LRNG_POOL_SIZE_BITS));
+ irq_num_events -= irq_num_events_used;
+ atomic_set(&irq_info->num_events, irq_num_events);
+
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ /* Obtain entropy statement in bits from the used entropy */
+ pr_debug("obtained %u bits of entropy from %u newly collected interrupts - not using %u interrupts\n",
+ requested_entropy_bits, irq_num_events_used,
+ irq_num_events);
+
+ return requested_entropy_bits;
+}
+
+/* Fill the seed buffer with data from the noise sources */
+int lrng_fill_seed_buffer(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct entropy_buf *entropy_buf, u32 entropy_retain)
+{
+ struct lrng_state *state = &lrng_state;
+ u32 total_entropy_bits = 0;
+
+ /* Require at least 128 bits of entropy for any reseed. */
+ if (state->lrng_fully_seeded &&
+ (lrng_avail_entropy() <
+ lrng_slow_noise_req_entropy(LRNG_MIN_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS) +
+ entropy_retain))
+ goto wakeup;
+
+ /*
+ * Concatenate the output of the noise sources. This would be the
+ * spot to add an entropy extractor logic if desired. Note, this
+ * has the ability to collect entropy equal or larger than the DRNG
+ * strength.
+ */
+ total_entropy_bits = lrng_get_pool(crypto_cb, hash, entropy_buf->a,
+ LRNG_DRNG_SECURITY_STRENGTH_BITS,
+ entropy_retain);
+ total_entropy_bits += lrng_get_arch(entropy_buf->b);
+ total_entropy_bits += lrng_get_jent(entropy_buf->c,
+ LRNG_DRNG_SECURITY_STRENGTH_BYTES);
+
+ /* also reseed the DRNG with the current time stamp */
+ entropy_buf->now = random_get_entropy();
+
+ /* allow external entropy provider to provide seed */
+ lrng_state_exseed_allow_all();
+
+wakeup:
+ /*
+ * Shall we wake up user space writers? This location covers
+ * ensures that the user space provider does not dominate the internal
+ * noise sources since in case the first call of this function finds
+ * sufficient entropy in the entropy pool, it will not trigger the
+ * wakeup. This implies that when the next /dev/urandom read happens,
+ * the entropy pool is drained.
+ */
+ lrng_writer_wakeup();
+
+ return total_entropy_bits;
+}
+
+/**
+ * lrng_init_ops() - Set seed stages of LRNG
+ *
+ * Set the slow noise source reseed trigger threshold. The initial threshold
+ * is set to the minimum data size that can be read from the pool: a word. Upon
+ * reaching this value, the next seed threshold of 128 bits is set followed
+ * by 256 bits.
+ *
+ * @entropy_bits: size of entropy currently injected into DRNG
+ */
+void lrng_init_ops(u32 seed_bits)
+{
+ struct lrng_state *state = &lrng_state;
+
+ if (state->lrng_operational)
+ return;
+
+ /* DRNG is seeded with full security strength */
+ if (state->lrng_fully_seeded) {
+ state->lrng_operational = lrng_sp80090b_startup_complete();
+ lrng_process_ready_list();
+ lrng_init_wakeup();
+ } else if (seed_bits >= LRNG_FULL_SEED_ENTROPY_BITS) {
+ invalidate_batched_entropy();
+ state->lrng_fully_seeded = true;
+ state->lrng_operational = lrng_sp80090b_startup_complete();
+ state->lrng_min_seeded = true;
+ pr_info("LRNG fully seeded with %u bits of entropy\n",
+ seed_bits);
+ lrng_set_entropy_thresh(LRNG_FULL_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS);
+ lrng_process_ready_list();
+ lrng_init_wakeup();
+
+ } else if (!state->lrng_min_seeded) {
+
+ /* DRNG is seeded with at least 128 bits of entropy */
+ if (seed_bits >= LRNG_MIN_SEED_ENTROPY_BITS) {
+ invalidate_batched_entropy();
+ state->lrng_min_seeded = true;
+ pr_info("LRNG minimally seeded with %u bits of entropy\n",
+ seed_bits);
+ lrng_set_entropy_thresh(
+ lrng_slow_noise_req_entropy(
+ LRNG_FULL_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS));
+ lrng_process_ready_list();
+ lrng_init_wakeup();
+
+ /* DRNG is seeded with at least LRNG_INIT_ENTROPY_BITS bits */
+ } else if (seed_bits >= LRNG_INIT_ENTROPY_BITS) {
+ pr_info("LRNG initial entropy level %u bits of entropy\n",
+ seed_bits);
+ lrng_set_entropy_thresh(
+ lrng_slow_noise_req_entropy(
+ LRNG_MIN_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS));
+ }
+ }
+}
+
+int __init rand_initialize(void)
+{
+ ktime_t now_time = ktime_get_real();
+ unsigned long rand;
+ unsigned int i;
+
+ lrng_drng_init_early();
+
+ lrng_pool_lfsr_u32(now_time);
+ for (i = 0; i < LRNG_POOL_SIZE; i++) {
+ if (!arch_get_random_seed_long_early(&rand) &&
+ !arch_get_random_long_early(&rand))
+ rand = random_get_entropy();
+ lrng_pool_lfsr((u8 *)&rand, sizeof(rand));
+ }
+ lrng_pool_lfsr_nonaligned((u8 *)utsname(), sizeof(*(utsname())));
+
+ return 0;
+}
diff --git a/drivers/char/lrng/lrng_sw_noise.c b/drivers/char/lrng/lrng_sw_noise.c
new file mode 100644
index 000000000000..1183d77005ac
--- /dev/null
+++ b/drivers/char/lrng/lrng_sw_noise.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Slow Noise Source: Interrupt data collection
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#include <asm/irq_regs.h>
+#include <asm/ptrace.h>
+#include <linux/random.h>
+
+#include "lrng_internal.h"
+#include "lrng_sw_noise.h"
+
+/* Holder of time stamps before mixing them into the entropy pool */
+static DEFINE_PER_CPU(u32 [LRNG_TIME_ARRAY_SIZE], lrng_time);
+static DEFINE_PER_CPU(u32, lrng_time_ptr) = 0;
+static DEFINE_PER_CPU(u8, lrng_time_irqs) = 0;
+
+/*
+ * Batching up of entropy in per-CPU array before injecting into entropy pool.
+ *
+ * The random32_data is solely to be used for the external random32 PRNG.
+ */
+static inline void lrng_time_process(u32 random32_data)
+{
+ u32 i, ptr, now_time = random_get_entropy();
+ u32 now_time_masked = now_time & LRNG_TIME_SLOTSIZE_MASK;
+ enum lrng_health_res health_test;
+
+ /* Ensure sufficient space in lrng_time_irqs */
+ BUILD_BUG_ON(LRNG_TIME_NUM_VALUES >= (1 << (sizeof(u8) << 3)));
+ BUILD_BUG_ON(LRNG_TIME_ARRAY_MEMBER_BITS % LRNG_TIME_SLOTSIZE_BITS);
+ /* Ensure consistency of values */
+ BUILD_BUG_ON(LRNG_TIME_ARRAY_MEMBER_BITS != sizeof(lrng_time[0]) << 3);
+
+ /* During boot time, we mix the full time stamp directly into LFSR */
+ if (unlikely(!lrng_state_fully_seeded())) {
+
+ /* Seed random32 PRNG with data not used by LRNG. */
+ this_cpu_add(net_rand_state.s1, random32_data);
+
+ if (lrng_raw_hires_entropy_store(now_time))
+ goto out;
+
+ health_test = lrng_health_test(now_time);
+ if (health_test > lrng_health_fail_use)
+ goto out;
+
+ lrng_pool_lfsr_u32(now_time);
+ if (health_test == lrng_health_pass)
+ lrng_pool_add_irq(1);
+ goto out;
+ }
+
+ /* Runtime operation */
+ if (lrng_raw_hires_entropy_store(now_time_masked))
+ goto out;
+
+ /* Seed random32 PRNG with data not used by LRNG. */
+ this_cpu_add(net_rand_state.s1,
+ (now_time & ~LRNG_TIME_SLOTSIZE_MASK) ^ random32_data);
+
+ health_test = lrng_health_test(now_time_masked);
+ if (health_test > lrng_health_fail_use)
+ goto out;
+
+ ptr = this_cpu_inc_return(lrng_time_ptr) & LRNG_TIME_WORD_MASK;
+ this_cpu_or(lrng_time[lrng_time_idx2array(ptr)],
+ lrng_time_slot_val(now_time_masked,
+ lrng_time_idx2slot(ptr)));
+
+ /* Interrupt delivers entropy if health test passes */
+ if (health_test == lrng_health_pass)
+ this_cpu_inc(lrng_time_irqs);
+
+ /* Only mix the buffer of time stamps into LFSR when wrapping */
+ if (ptr < LRNG_TIME_WORD_MASK)
+ goto out;
+
+ for (i = 0; i < LRNG_TIME_ARRAY_SIZE; i++) {
+ if (lrng_raw_array_entropy_store(this_cpu_read(lrng_time[i]))) {
+ /*
+ * If we fed even a part of the array to external
+ * analysis, we mark that the entire array has no
+ * entropy. This is due to the non-IID property of
+ * the data as we do not fully know whether the
+ * existing dependencies diminish the entropy beyond
+ * to what we expect it has.
+ */
+ this_cpu_write(lrng_time_irqs, 0);
+ } else {
+ lrng_pool_lfsr_u32(this_cpu_read(lrng_time[i]));
+ }
+
+ this_cpu_write(lrng_time[i], 0);
+ }
+ lrng_pool_add_irq(this_cpu_read(lrng_time_irqs));
+ this_cpu_write(lrng_time_irqs, 0);
+
+out:
+ lrng_perf_time(now_time);
+}
+
+/*
+ * Hot code path - Callback for interrupt handler
+ */
+void add_interrupt_randomness(int irq, int irq_flags)
+{
+ if (lrng_pool_highres_timer()) {
+ lrng_time_process(
+ (lrng_raw_irq_entropy_store(irq) ? 0 : irq) ^
+ (lrng_raw_irqflags_entropy_store(irq_flags) ? 0 :
+ irq_flags) ^
+ (lrng_raw_retip_entropy_store(_RET_IP_) ? 0 :
+ _RET_IP_));
+ } else {
+ struct pt_regs *regs = get_irq_regs();
+ static atomic_t reg_idx = ATOMIC_INIT(0);
+ u64 ip;
+
+ if (regs) {
+ u32 *ptr = (u32 *)regs;
+ int reg_ptr = atomic_add_return_relaxed(1, ®_idx);
+ size_t n = (sizeof(struct pt_regs) / sizeof(u32));
+
+ ip = instruction_pointer(regs);
+ lrng_pool_lfsr_u32(*(ptr + (reg_ptr % n)));
+
+ lrng_time_process(
+ lrng_raw_retip_entropy_store(_RET_IP_) ? 0 :
+ _RET_IP_);
+ } else {
+ ip = _RET_IP_;
+
+ lrng_time_process(0);
+ }
+
+ /*
+ * The XOR operation combining the different values is not
+ * considered to destroy entropy since the entirety of all
+ * processed values delivers the entropy (and not each
+ * value separately of the other values).
+ */
+ lrng_pool_lfsr_u32(
+ (lrng_raw_jiffies_entropy_store(jiffies) ? 0 :
+ jiffies) ^
+ (lrng_raw_irq_entropy_store(irq) ? 0 : irq) ^
+ (lrng_raw_irqflags_entropy_store(irq_flags) ? 0 :
+ irq_flags) ^
+ (ip >> 32) ^
+ (lrng_raw_retip_entropy_store(ip) ? 0 : ip));
+ }
+}
+EXPORT_SYMBOL(add_interrupt_randomness);
diff --git a/drivers/char/lrng/lrng_sw_noise.h b/drivers/char/lrng/lrng_sw_noise.h
new file mode 100644
index 000000000000..919d8c368991
--- /dev/null
+++ b/drivers/char/lrng/lrng_sw_noise.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * LRNG Slow Noise Source: Time stamp array handling
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+/*
+ * To limit the impact on the interrupt handling, the LRNG concatenates
+ * entropic LSB parts of the time stamps in a per-CPU array and only
+ * injects them into the entropy pool when the array is full.
+ */
+
+/* Store multiple integers in one u32 */
+#define LRNG_TIME_SLOTSIZE_BITS (8)
+#define LRNG_TIME_SLOTSIZE_MASK ((1 << LRNG_TIME_SLOTSIZE_BITS) - 1)
+#define LRNG_TIME_ARRAY_MEMBER_BITS (4 << 3) /* ((sizeof(u32)) << 3) */
+#define LRNG_TIME_SLOTS_PER_UINT (LRNG_TIME_ARRAY_MEMBER_BITS / \
+ LRNG_TIME_SLOTSIZE_BITS)
+
+/*
+ * Number of time values to store in the array - in small environments
+ * only one atomic_t variable per CPU is used.
+ */
+#define LRNG_TIME_NUM_VALUES (CONFIG_BASE_SMALL ? \
+ LRNG_TIME_SLOTS_PER_UINT : 64)
+/* Mask of LSB of time stamp to store */
+#define LRNG_TIME_WORD_MASK (LRNG_TIME_NUM_VALUES - 1)
+
+#define LRNG_TIME_SLOTS_MASK (LRNG_TIME_SLOTS_PER_UINT - 1)
+#define LRNG_TIME_ARRAY_SIZE (LRNG_TIME_NUM_VALUES / \
+ LRNG_TIME_SLOTS_PER_UINT)
+
+/* Starting bit index of slot */
+static inline unsigned int lrng_time_slot2bitindex(unsigned int slot)
+{
+ return (LRNG_TIME_SLOTSIZE_BITS * slot);
+}
+
+/* Convert index into the array index */
+static inline unsigned int lrng_time_idx2array(unsigned int idx)
+{
+ return idx / LRNG_TIME_SLOTS_PER_UINT;
+}
+
+/* Convert index into the slot of a given array index */
+static inline unsigned int lrng_time_idx2slot(unsigned int idx)
+{
+ return idx & LRNG_TIME_SLOTS_MASK;
+}
+
+/* Convert value into slot value */
+static inline unsigned int lrng_time_slot_val(unsigned int val,
+ unsigned int slot)
+{
+ return val << lrng_time_slot2bitindex(slot);
+}
diff --git a/include/linux/lrng.h b/include/linux/lrng.h
new file mode 100644
index 000000000000..2c3d2ed32a91
--- /dev/null
+++ b/include/linux/lrng.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * Copyright (C) 2018 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#ifndef _LRNG_H
+#define _LRNG_H
+
+#include <linux/errno.h>
+#include <linux/types.h>
+
+/**
+ * struct lrng_crypto_cb - cryptographic callback functions
+ * @lrng_drng_name Name of DRNG
+ * @lrng_hash_name Name of Hash used for reading entropy pool
+ * @lrng_drng_alloc: Allocate DRNG -- the provided integer should be
+ * used for sanity checks.
+ * return: allocated data structure or PTR_ERR on
+ * error
+ * @lrng_drng_dealloc: Deallocate DRNG
+ * @lrng_drng_seed_helper: Seed the DRNG with data of arbitrary length
+ * drng: is pointer to data structure allocated
+ * with lrng_drng_alloc
+ * return: >= 0 on success, < 0 on error
+ * @lrng_drng_generate_helper: Generate random numbers from the DRNG with
+ * arbitrary length
+ * @lrng_hash_alloc: Allocate the hash for reading the entropy pool
+ * return: allocated data structure (NULL is
+ * success too) or ERR_PTR on error
+ * @lrng_hash_dealloc: Deallocate Hash
+ * @lrng_hash_digestsize: Return the digestsize for the used hash to read
+ * out entropy pool
+ * hash: is pointer to data structure allocated
+ * with lrng_hash_alloc
+ * return: size of digest of hash in bytes
+ * @lrng_hash_buffer: Generate hash
+ * hash: is pointer to data structure allocated
+ * with lrng_hash_alloc
+ * return: 0 on success, < 0 on error
+ */
+struct lrng_crypto_cb {
+ const char *(*lrng_drng_name)(void);
+ const char *(*lrng_hash_name)(void);
+ void *(*lrng_drng_alloc)(u32 sec_strength);
+ void (*lrng_drng_dealloc)(void *drng);
+ int (*lrng_drng_seed_helper)(void *drng, const u8 *inbuf, u32 inbuflen);
+ int (*lrng_drng_generate_helper)(void *drng, u8 *outbuf, u32 outbuflen);
+ void *(*lrng_hash_alloc)(const u8 *key, u32 keylen);
+ void (*lrng_hash_dealloc)(void *hash);
+ u32 (*lrng_hash_digestsize)(void *hash);
+ int (*lrng_hash_buffer)(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest);
+};
+
+/* Register cryptographic backend */
+#ifdef CONFIG_LRNG_DRNG_SWITCH
+int lrng_set_drng_cb(const struct lrng_crypto_cb *cb);
+#else /* CONFIG_LRNG_DRNG_SWITCH */
+static inline int
+lrng_set_drng_cb(const struct lrng_crypto_cb *cb) { return -EOPNOTSUPP; }
+#endif /* CONFIG_LRNG_DRNG_SWITCH */
+
+#endif /* _LRNG_H */
--
2.26.2
Hi "Stephan,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on char-misc/char-misc-testing]
[also build test ERROR on cryptodev/master crypto/master v5.9-rc1 next-20200821]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200821-140523
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git d162219c655c8cf8003128a13840d6c1e183fb80
config: parisc-allyesconfig (attached as .config)
compiler: hppa-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=parisc
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
hppa-linux-ld: lib/random32.o: in function `prandom_u32':
>> (.text+0x318): undefined reference to `__tracepoint_prandom_u32'
>> hppa-linux-ld: (.text+0x31c): undefined reference to `__tracepoint_prandom_u32'
>> hppa-linux-ld: lib/random32.o:(__jump_table+0x8): undefined reference to `__tracepoint_prandom_u32'
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Am Freitag, 21. August 2020, 21:42:17 CEST schrieb kernel test robot:
Hi,
>
> hppa-linux-ld: lib/random32.o: in function `prandom_u32':
> >> (.text+0x318): undefined reference to `__tracepoint_prandom_u32'
> >> hppa-linux-ld: (.text+0x31c): undefined reference to
> >> `__tracepoint_prandom_u32' hppa-linux-ld:
> >> lib/random32.o:(__jump_table+0x8): undefined reference to
> >> `__tracepoint_prandom_u32'
This is caused by the fact that the LRNG code does not include trace/events/
random.h. However, a patch to lib/random32.c now requires this file to be
included and creating a tracepoint. I.e. lib/random32.c code now relies on
some other code to create the necessary hook.
I have added the include and will provide it with the next release although I
am not sure lib/random32.c should rely on some other code to create its
dependencies.
Ciao
Stephan
Hi,
The following patch set provides a different approach to /dev/random which is
called Linux Random Number Generator (LRNG) to collect entropy within the Linux
kernel. The main improvements compared to the existing /dev/random is to provide
sufficient entropy during boot time as well as in virtual environments and when
using SSDs. A secondary design goal is to limit the impact of the entropy
collection on massive parallel systems and also allow the use accelerated
cryptographic primitives. Also, all steps of the entropic data processing are
testable.
The LRNG patch set allows a user to select use of the existing /dev/random or
the LRNG during compile time. As the LRNG provides API and ABI compatible
interfaces to the existing /dev/random implementation, the user can freely chose
the RNG implementation without affecting kernel or user space operations.
This patch set provides early boot-time entropy which implies that no
additional flags to the getrandom(2) system call discussed recently on
the LKML is considered to be necessary. Yet, if additional flags are
introduced to cover special hardware, the LRNG implementation will also
provide them to be fully ABI and API compliant as already discussed on
LKML.
The LRNG is fully compliant to SP800-90B requirements and is shipped with a
full SP800-90B assessment and all required test tools. The existing /dev/random
implementation on the other hand has architectural limitations which
does not easily allow to bring the implementation in compliance with
SP800-90B. The key statement that causes concern is SP800-90B section
3.1.6. This section denies crediting entropy to multiple similar noise
sources. This section explicitly references different noise sources resting
on the timing of events and their derivatives (i.e. it is a direct complaint
to the existing existing /dev/random implementation). Therefore, SP800-90B
now denies the very issue mentioned in [1] with the existing /dev/random
implementation for a long time: crediting entropy to interrupts as well as
crediting entropy to derivatives of interrupts (HID and disk events). This is
not permissible with SP800-90B.
SP800-90B specifies various requirements for the noise source(s) that seed any
DRNG including SP800-90A DRBGs. In about a year from now, SP800-90B will be
mandated for all noise sources that provide entropy to DRBGs as part of a FIPS
140-[2|3] validation or other evaluation types. That means, if we there are no
solutions to comply with the requirements of SP800-90B found till one year
from now, any random number generation and ciphers based on random numbers
on Linux will be considered and treated as not applicable and delivering
no entropy! As /dev/urandom, getrandom(2) and /dev/random are the most
common and prevalent noise sources for DRNGs, all these DRNGs are affected.
This applies across the board for all validations of cryptography executing on
Linux (kernel and user space modules).
For users that are not interested in SP800-90B, the entire code for the
compliance as well as test interfaces can be deselected at compile time.
The design and implementation is driven by a set of goals described in [1]
that the LRNG completely implements. Furthermore, [1] includes the full
assessment of the SP800-90B compliance as well as a comparison with RNG
design suggestions of SP800-90C, and AIS20/31.
The LRNG provides a complete separation of the noise source maintenance
and the collection of entropy into an entropy pool from the post-processing
using a pseudo-random number generator. Different DRNGs are supported,
including:
* The LRNG can be compile-time enabled to replace the existing /dev/random
implementation. When not selecting the LRNG at compile time (default), the
existing /dev/random implementation is built.
* Built-in ChaCha20 DRNG which has no dependency to other kernel
frameworks.
* SP800-90A DRBG using the kernel crypto API including its accelerated
raw cipher implementations. This implies that the output of /dev/random,
getrandom(2), /dev/urandom or get_random_bytes is fully compliant to
SP800-90A.
* Arbitrary DRNGs registered with the kernel crypto API
* Full compliance with SP800-90B which covers the startup and runtime health
tests mandated by SP800-90B as well as providing the test tools and test
interfaces to obtain raw noise data securely. The test tools are provided at
[1].
Booting the patch with the kernel command line option
"dyndbg=file drivers/char/lrng/* +p" generates logs indicating the operation
of the LRNG. Each log is pre-pended with "lrng".
The LRNG has a flexible design by allowing an easy replacement of the
deterministic random number generator component.
Compared to the existing /dev/random implementation, the compiled binary
is smaller when the LRNG is compiled with all options equal to the
existing /dev/random (i.e. only CONFIG_LRNG is set): random.o is 52.5 kBytes
whereas all LRNG object files are in 49 kBytes in size. The fully
SP800-90A/SP800-90B compliant binary code (CONFIG_LRNG,
CONFIG_LRNG_DRNG_SWITCH, CONFIG_LRNG_DRBG, CONFIG_LRNG_HEALTH_TESTS)
uses some 61 kBytes. In addition, the LRNG is about 50% faster in the
performance critical interrupt handler code path compared to the existing
/dev/random implementation.
Full SP800-90B testing is performed on the following systems - details
are given in [2] appendix C:
* x86 KVM virtualized guest 32 and 64 bit systems
* x86 bare metal
* older and newer ARMv7 system
* ARM64
* POWER7 LE and POWER 8 BE
* IBM Z System mainframe
* old MIPS embedded device
[1] https://www.chronox.de/lrng.html - If the patch is accepted, I would
be volunteering to convert the documentation into RST format and
contribute it to the Linux kernel documentation directory.
[2] https://www.chronox.de/lrng/doc/lrng.pdf
Changes (compared to the previous patch set):
* fix all sparse warnings, partially reported by kernel test robot
<[email protected]>
* ensure that DRBG or KCAPI backend can only be exclusively compiled if
it is selected for static compilation - suggested by
Andy Lavr <[email protected]>
* fix Kconfig to enable compilation of lrng_testing.c in all possible
configurations reported by kernel test robot
<[email protected]>
* include trace/events/random.h to make lib/random32.c happy (even
though the LRNG does not need this header file) reported by kernel
test robot <[email protected]>
As a side node: With the switchable DRNG support offered in this patch set,
the following areas could be removed. As the existing /dev/random has no support
for switchable DRNGs, however, this is not yet feasible though.
* remove lrng_ready_list and all code around it in lrng_interfaces.c
* remove the kernel crypto API RNG API to avoid having two random number
providing APIs - this would imply that all RNGs developed for this API would
be converted to the LRNG interface
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Stephan Mueller (12):
Linux Random Number Generator
LRNG - allocate one DRNG instance per NUMA node
LRNG - sysctls and /proc interface
LRNG - add switchable DRNG support
crypto: DRBG - externalize DRBG functions for LRNG
LRNG - add SP800-90A DRBG extension
LRNG - add kernel crypto API PRNG extension
crypto: provide access to a static Jitter RNG state
LRNG - add Jitter RNG fast noise source
LRNG - add SP800-90B compliant health tests
LRNG - add interface for gathering of raw entropy
LRNG - add power-on and runtime self-tests
MAINTAINERS | 7 +
crypto/drbg.c | 16 +-
crypto/jitterentropy-kcapi.c | 3 +-
crypto/jitterentropy.c | 31 +-
drivers/char/Kconfig | 2 +
drivers/char/Makefile | 9 +-
drivers/char/lrng/Kconfig | 316 +++++++++
drivers/char/lrng/Makefile | 19 +
drivers/char/lrng/lrng_archrandom.c | 93 +++
drivers/char/lrng/lrng_aux.c | 136 ++++
drivers/char/lrng/lrng_chacha20.c | 321 +++++++++
drivers/char/lrng/lrng_chacha20.h | 29 +
drivers/char/lrng/lrng_drbg.c | 259 +++++++
drivers/char/lrng/lrng_drng.c | 409 +++++++++++
drivers/char/lrng/lrng_health.c | 407 +++++++++++
drivers/char/lrng/lrng_interfaces.c | 651 ++++++++++++++++++
drivers/char/lrng/lrng_internal.h | 351 ++++++++++
drivers/char/lrng/lrng_jent.c | 88 +++
drivers/char/lrng/lrng_kcapi.c | 321 +++++++++
drivers/char/lrng/lrng_lfsr.h | 152 ++++
drivers/char/lrng/lrng_numa.c | 101 +++
drivers/char/lrng/lrng_pool.c | 589 ++++++++++++++++
drivers/char/lrng/lrng_proc.c | 163 +++++
drivers/char/lrng/lrng_selftest.c | 506 ++++++++++++++
drivers/char/lrng/lrng_sw_noise.c | 155 +++++
drivers/char/lrng/lrng_sw_noise.h | 57 ++
drivers/char/lrng/lrng_switch.c | 193 ++++++
drivers/char/lrng/lrng_testing.c | 575 ++++++++++++++++
include/crypto/drbg.h | 7 +
.../crypto/internal}/jitterentropy.h | 3 +
include/linux/lrng.h | 63 ++
31 files changed, 6022 insertions(+), 10 deletions(-)
create mode 100644 drivers/char/lrng/Kconfig
create mode 100644 drivers/char/lrng/Makefile
create mode 100644 drivers/char/lrng/lrng_archrandom.c
create mode 100644 drivers/char/lrng/lrng_aux.c
create mode 100644 drivers/char/lrng/lrng_chacha20.c
create mode 100644 drivers/char/lrng/lrng_chacha20.h
create mode 100644 drivers/char/lrng/lrng_drbg.c
create mode 100644 drivers/char/lrng/lrng_drng.c
create mode 100644 drivers/char/lrng/lrng_health.c
create mode 100644 drivers/char/lrng/lrng_interfaces.c
create mode 100644 drivers/char/lrng/lrng_internal.h
create mode 100644 drivers/char/lrng/lrng_jent.c
create mode 100644 drivers/char/lrng/lrng_kcapi.c
create mode 100644 drivers/char/lrng/lrng_lfsr.h
create mode 100644 drivers/char/lrng/lrng_numa.c
create mode 100644 drivers/char/lrng/lrng_pool.c
create mode 100644 drivers/char/lrng/lrng_proc.c
create mode 100644 drivers/char/lrng/lrng_selftest.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.h
create mode 100644 drivers/char/lrng/lrng_switch.c
create mode 100644 drivers/char/lrng/lrng_testing.c
rename {crypto => include/crypto/internal}/jitterentropy.h (84%)
create mode 100644 include/linux/lrng.h
--
2.26.2
The DRNG switch support allows replacing the DRNG mechanism of the
LRNG. The switching support rests on the interface definition of
include/linux/lrng.h. A new DRNG is implemented by filling in the
interface defined in this header file.
In addition to the DRNG, the extension also has to provide a hash
implementation that is used to hash the entropy pool for random number
extraction.
Note: It is permissible to implement a DRNG whose operations may sleep.
However, the hash function must not sleep.
The switchable DRNG support allows replacing the DRNG at runtime.
However, only one DRNG extension is allowed to be loaded at any given
time. Before replacing it with another DRNG implementation, the possibly
existing DRNG extension must be unloaded.
The switchable DRNG extension activates the new DRNG during load time.
It is expected, however, that such a DRNG switch would be done only once
by an administrator to load the intended DRNG implementation.
It is permissible to compile DRNG extensions either as kernel modules or
statically. The initialization of the DRNG extension should be performed
with a late_initcall to ensure the extension is available when user
space starts but after all other initialization completed.
The initialization is performed by registering the function call data
structure with the lrng_set_drng_cb function. In order to unload the
DRNG extension, lrng_set_drng_cb must be invoked with the NULL
parameter.
The DRNG extension should always provide a security strength that is at
least as strong as LRNG_DRNG_SECURITY_STRENGTH_BITS.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Marcelo Henrique Cerri <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Kconfig | 7 ++
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_switch.c | 193 ++++++++++++++++++++++++++++++++
3 files changed, 201 insertions(+)
create mode 100644 drivers/char/lrng/lrng_switch.c
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
index 059b21d9728c..d3138458fd8b 100644
--- a/drivers/char/lrng/Kconfig
+++ b/drivers/char/lrng/Kconfig
@@ -65,4 +65,11 @@ config LRNG_POOL_SIZE
default 7 if LRNG_POOL_SIZE_65536
default 8 if LRNG_POOL_SIZE_131072
+menuconfig LRNG_DRNG_SWITCH
+ bool "Support DRNG runtime switching"
+ help
+ The Linux RNG per default uses a ChaCha20 DRNG that is
+ accessible via the external interfaces. With this configuration
+ option other DRNGs can be selected and loaded at runtime.
+
endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index e69c176f0161..31cfe87c999e 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -10,3 +10,4 @@ obj-y += lrng_pool.o lrng_aux.o \
obj-$(CONFIG_NUMA) += lrng_numa.o
obj-$(CONFIG_SYSCTL) += lrng_proc.o
+obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o
diff --git a/drivers/char/lrng/lrng_switch.c b/drivers/char/lrng/lrng_switch.c
new file mode 100644
index 000000000000..9b40671c6375
--- /dev/null
+++ b/drivers/char/lrng/lrng_switch.c
@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG DRNG switching support
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/lrng.h>
+
+#include "lrng_internal.h"
+
+static int lrng_drng_switch(struct lrng_drng *drng_store,
+ const struct lrng_crypto_cb *cb, int node)
+{
+ const struct lrng_crypto_cb *old_cb;
+ unsigned long flags = 0;
+ int ret;
+ u8 seed[LRNG_DRNG_SECURITY_STRENGTH_BYTES] __latent_entropy;
+ void *new_drng = cb->lrng_drng_alloc(LRNG_DRNG_SECURITY_STRENGTH_BYTES);
+ void *old_drng, *new_hash, *old_hash;
+ bool sl = false, reset_drng = !lrng_get_available();
+
+ if (IS_ERR(new_drng)) {
+ pr_warn("could not allocate new DRNG for NUMA node %d (%ld)\n",
+ node, PTR_ERR(new_drng));
+ return PTR_ERR(new_drng);
+ }
+
+ /*
+ * The seed potentially used as MAC key is undefined to add some
+ * variation. Yet, the security of the MAC does not rely on the key
+ * being secret. The key is only there to turn a MAC into a hash.
+ * The intention is to allow the specification of CMAC(AES) as "hash"
+ * to limit the dependency to AES when using the CTR DRBG.
+ */
+ new_hash = cb->lrng_hash_alloc(seed, sizeof(seed));
+ if (IS_ERR(new_hash)) {
+ pr_warn("could not allocate new LRNG pool hash (%ld)\n",
+ PTR_ERR(new_hash));
+ cb->lrng_drng_dealloc(new_drng);
+ return PTR_ERR(new_hash);
+ }
+
+ lrng_drng_lock(drng_store, &flags);
+
+ /*
+ * Pull from existing DRNG to seed new DRNG regardless of seed status
+ * of old DRNG -- the entropy state for the DRNG is left unchanged which
+ * implies that als the new DRNG is reseeded when deemed necessary. This
+ * seeding of the new DRNG shall only ensure that the new DRNG has the
+ * same entropy as the old DRNG.
+ */
+ ret = drng_store->crypto_cb->lrng_drng_generate_helper(
+ drng_store->drng, seed, sizeof(seed));
+ lrng_drng_unlock(drng_store, &flags);
+
+ if (ret < 0) {
+ reset_drng = true;
+ pr_warn("getting random data from DRNG failed for NUMA node %d (%d)\n",
+ node, ret);
+ } else {
+ /* seed new DRNG with data */
+ ret = cb->lrng_drng_seed_helper(new_drng, seed, ret);
+ if (ret < 0) {
+ reset_drng = true;
+ pr_warn("seeding of new DRNG failed for NUMA node %d (%d)\n",
+ node, ret);
+ } else {
+ pr_debug("seeded new DRNG of NUMA node %d instance from old DRNG instance\n",
+ node);
+ }
+ }
+
+ mutex_lock(&drng_store->lock);
+ /*
+ * If we switch the DRNG from the initial ChaCha20 DRNG to something
+ * else, there is a lock transition from spin lock to mutex (see
+ * lrng_drng_is_atomic and how the lock is taken in lrng_drng_lock).
+ * Thus, we need to take both locks during the transition phase.
+ */
+ if (lrng_drng_is_atomic(drng_store)) {
+ spin_lock_irqsave(&drng_store->spin_lock, flags);
+ sl = true;
+ } else {
+ __acquire(&drng_store->spin_lock);
+ }
+
+ if (reset_drng)
+ lrng_drng_reset(drng_store);
+
+ old_drng = drng_store->drng;
+ old_cb = drng_store->crypto_cb;
+ drng_store->drng = new_drng;
+ drng_store->crypto_cb = cb;
+
+ old_hash = drng_store->hash;
+ drng_store->hash = new_hash;
+ pr_info("Entropy pool read-hash allocated for DRNG for NUMA node %d\n",
+ node);
+
+ if (sl)
+ spin_unlock_irqrestore(&drng_store->spin_lock, flags);
+ else
+ __release(&drng_store->spin_lock);
+ mutex_unlock(&drng_store->lock);
+
+ /* ChaCha20 serves as atomic instance left untouched. */
+ if (old_drng != &chacha20) {
+ old_cb->lrng_drng_dealloc(old_drng);
+ old_cb->lrng_hash_dealloc(old_hash);
+ }
+
+ pr_info("DRNG of NUMA node %d switched\n", node);
+
+ return 0;
+}
+
+/*
+ * Switch the existing DRNG instances with new using the new crypto callbacks.
+ * The caller must hold the lrng_crypto_cb_update lock.
+ */
+static int lrng_drngs_switch(const struct lrng_crypto_cb *cb)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ struct lrng_drng *lrng_drng_init = lrng_drng_init_instance();
+ int ret = 0;
+
+ /* Update DRNG */
+ if (lrng_drng) {
+ u32 node;
+
+ for_each_online_node(node) {
+ if (lrng_drng[node])
+ ret = lrng_drng_switch(lrng_drng[node], cb,
+ node);
+ }
+ } else {
+ ret = lrng_drng_switch(lrng_drng_init, cb, 0);
+ }
+
+ if (!ret)
+ lrng_set_available();
+
+ return 0;
+}
+
+/**
+ * lrng_set_drng_cb - Register new cryptographic callback functions for DRNG
+ * The registering implies that all old DRNG states are replaced with new
+ * DRNG states.
+ *
+ * @cb: Callback functions to be registered -- if NULL, use the default
+ * callbacks pointing to the ChaCha20 DRNG.
+ *
+ * Return:
+ * * 0 on success
+ * * < 0 on error
+ */
+int lrng_set_drng_cb(const struct lrng_crypto_cb *cb)
+{
+ struct lrng_drng *lrng_drng_init = lrng_drng_init_instance();
+ int ret;
+
+ if (!cb)
+ cb = &lrng_cc20_crypto_cb;
+
+ mutex_lock(&lrng_crypto_cb_update);
+
+ /*
+ * If a callback other than the default is set, allow it only to be
+ * set back to the default callback. This ensures that multiple
+ * different callbacks can be registered at the same time. If a
+ * callback different from the current callback and the default
+ * callback shall be set, the current callback must be deregistered
+ * (e.g. the kernel module providing it must be unloaded) and the new
+ * implementation can be registered.
+ */
+ if ((cb != &lrng_cc20_crypto_cb) &&
+ (lrng_drng_init->crypto_cb != &lrng_cc20_crypto_cb)) {
+ pr_warn("disallow setting new cipher callbacks, unload the old callbacks first!\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = lrng_drngs_switch(cb);
+
+out:
+ mutex_unlock(&lrng_crypto_cb_update);
+ return ret;
+}
+EXPORT_SYMBOL(lrng_set_drng_cb);
--
2.26.2
Using the LRNG switchable DRNG support, the SP800-90A DRBG extension is
implemented.
The DRBG uses the kernel crypto API DRBG implementation. In addition, it
uses the kernel crypto API SHASH support to provide the hashing
operation.
The DRBG supports the choice of either a CTR DRBG using AES-256, HMAC
DRBG with SHA-512 core or Hash DRBG with SHA-512 core. The used core can
be selected with the module parameter lrng_drbg_type. The default is the
CTR DRBG.
When compiling the DRBG extension statically, the DRBG is loaded at
late_initcall stage which implies that with the start of user space, the
user space interfaces of getrandom(2), /dev/random and /dev/urandom
provide random data produced by an SP800-90A DRBG.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Kconfig | 12 ++
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_drbg.c | 259 ++++++++++++++++++++++++++++++++++
3 files changed, 272 insertions(+)
create mode 100644 drivers/char/lrng/lrng_drbg.c
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
index d3138458fd8b..4f2b757a8962 100644
--- a/drivers/char/lrng/Kconfig
+++ b/drivers/char/lrng/Kconfig
@@ -72,4 +72,16 @@ menuconfig LRNG_DRNG_SWITCH
accessible via the external interfaces. With this configuration
option other DRNGs can be selected and loaded at runtime.
+if LRNG_DRNG_SWITCH
+config LRNG_DRBG
+ tristate "SP800-90A support for the LRNG"
+ depends on CRYPTO
+ select CRYPTO_DRBG_MENU
+ select CRYPTO_SHA512
+ help
+ Enable the SP800-90A DRBG support for the LRNG. Once the
+ module is loaded, output from /dev/random, /dev/urandom,
+ getrandom(2), or get_random_bytes_full is provided by a DRBG.
+endif # LRNG_DRNG_SWITCH
+
endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index 31cfe87c999e..0d320fcb7b9e 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -11,3 +11,4 @@ obj-y += lrng_pool.o lrng_aux.o \
obj-$(CONFIG_NUMA) += lrng_numa.o
obj-$(CONFIG_SYSCTL) += lrng_proc.o
obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o
+obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o
diff --git a/drivers/char/lrng/lrng_drbg.c b/drivers/char/lrng/lrng_drbg.c
new file mode 100644
index 000000000000..e6fbb5a82ff0
--- /dev/null
+++ b/drivers/char/lrng/lrng_drbg.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Backend for the LRNG providing the cryptographic primitives using the
+ * kernel crypto API and its DRBG.
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <crypto/drbg.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/lrng.h>
+
+/*
+ * Define a DRBG plus a hash / MAC used to extract data from the entropy pool.
+ * For LRNG_HASH_NAME you can use a hash or a MAC (HMAC or CMAC) of your choice
+ * (Note, you should use the suggested selections below -- using SHA-1 or MD5
+ * is not wise). The idea is that the used cipher primitive can be selected to
+ * be the same as used for the DRBG. I.e. the LRNG only uses one cipher
+ * primitive using the same cipher implementation with the options offered in
+ * the following. This means, if the CTR DRBG is selected and AES-NI is present,
+ * both the CTR DRBG and the selected cmac(aes) use AES-NI.
+ *
+ * The security strengths of the DRBGs are all 256 bits according to
+ * SP800-57 section 5.6.1.
+ *
+ * This definition is allowed to be changed.
+ */
+#ifdef CONFIG_CRYPTO_DRBG_CTR
+static unsigned int lrng_drbg_type = 0;
+#elif defined CONFIG_CRYPTO_DRBG_HMAC
+static unsigned int lrng_drbg_type = 1;
+#elif defined CONFIG_CRYPTO_DRBG_HASH
+static unsigned int lrng_drbg_type = 2;
+#else
+#error "Unknown DRBG in use"
+#endif
+
+/* The parameter must be r/o in sysfs as otherwise races appear. */
+module_param(lrng_drbg_type, uint, 0444);
+MODULE_PARM_DESC(lrng_drbg_type, "DRBG type used for LRNG (0->CTR_DRBG, 1->HMAC_DRBG, 2->Hash_DRBG)");
+
+struct lrng_drbg {
+ const char *hash_name;
+ const char *drbg_core;
+};
+
+static const struct lrng_drbg lrng_drbg_types[] = {
+ { /* CTR_DRBG with AES-256 using derivation function */
+ .hash_name = "sha512",
+ .drbg_core = "drbg_nopr_ctr_aes256",
+ }, { /* HMAC_DRBG with SHA-512 */
+ .hash_name = "sha512",
+ .drbg_core = "drbg_nopr_hmac_sha512",
+ }, { /* Hash_DRBG with SHA-512 using derivation function */
+ .hash_name = "sha512",
+ .drbg_core = "drbg_nopr_sha512"
+ }
+};
+
+struct lrng_hash_info {
+ struct shash_desc shash;
+ char ctx[];
+};
+
+static int lrng_drbg_drng_seed_helper(void *drng, const u8 *inbuf, u32 inbuflen)
+{
+ struct drbg_state *drbg = (struct drbg_state *)drng;
+ LIST_HEAD(seedlist);
+ struct drbg_string data;
+ int ret;
+
+ drbg_string_fill(&data, inbuf, inbuflen);
+ list_add_tail(&data.list, &seedlist);
+ ret = drbg->d_ops->update(drbg, &seedlist, drbg->seeded);
+
+ if (ret >= 0)
+ drbg->seeded = true;
+
+ return ret;
+}
+
+static int lrng_drbg_drng_generate_helper(void *drng, u8 *outbuf, u32 outbuflen)
+{
+ struct drbg_state *drbg = (struct drbg_state *)drng;
+
+ return drbg->d_ops->generate(drbg, outbuf, outbuflen, NULL);
+}
+
+static void *lrng_drbg_drng_alloc(u32 sec_strength)
+{
+ struct drbg_state *drbg;
+ int coreref = -1;
+ bool pr = false;
+ int ret;
+
+ drbg_convert_tfm_core(lrng_drbg_types[lrng_drbg_type].drbg_core,
+ &coreref, &pr);
+ if (coreref < 0)
+ return ERR_PTR(-EFAULT);
+
+ drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
+ if (!drbg)
+ return ERR_PTR(-ENOMEM);
+
+ drbg->core = &drbg_cores[coreref];
+ drbg->seeded = false;
+ ret = drbg_alloc_state(drbg);
+ if (ret)
+ goto err;
+
+ if (sec_strength > drbg_sec_strength(drbg->core->flags)) {
+ pr_err("Security strength of DRBG (%u bits) lower than requested by LRNG (%u bits)\n",
+ drbg_sec_strength(drbg->core->flags) * 8,
+ sec_strength * 8);
+ goto dealloc;
+ }
+
+ if (sec_strength < drbg_sec_strength(drbg->core->flags))
+ pr_warn("Security strength of DRBG (%u bits) higher than requested by LRNG (%u bits)\n",
+ drbg_sec_strength(drbg->core->flags) * 8,
+ sec_strength * 8);
+
+ pr_info("DRBG with %s core allocated\n", drbg->core->backend_cra_name);
+
+ return drbg;
+
+dealloc:
+ if (drbg->d_ops)
+ drbg->d_ops->crypto_fini(drbg);
+ drbg_dealloc_state(drbg);
+err:
+ kfree(drbg);
+ return ERR_PTR(-EINVAL);
+}
+
+static void lrng_drbg_drng_dealloc(void *drng)
+{
+ struct drbg_state *drbg = (struct drbg_state *)drng;
+
+ if (drbg && drbg->d_ops)
+ drbg->d_ops->crypto_fini(drbg);
+ drbg_dealloc_state(drbg);
+ kzfree(drbg);
+ pr_info("DRBG deallocated\n");
+}
+
+static void *lrng_drbg_hash_alloc(const u8 *key, u32 keylen)
+{
+ struct lrng_hash_info *lrng_hash;
+ struct crypto_shash *tfm;
+ int size, ret;
+
+ tfm = crypto_alloc_shash(lrng_drbg_types[lrng_drbg_type].hash_name,
+ 0, 0);
+ if (IS_ERR(tfm)) {
+ pr_err("could not allocate hash %s\n",
+ lrng_drbg_types[lrng_drbg_type].hash_name);
+ return ERR_CAST(tfm);
+ }
+
+ size = sizeof(struct lrng_hash_info) + crypto_shash_descsize(tfm);
+ lrng_hash = kmalloc(size, GFP_KERNEL);
+ if (!lrng_hash) {
+ crypto_free_shash(tfm);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ lrng_hash->shash.tfm = tfm;
+
+ /* If the used hash is no MAC, ignore the ENOSYS return code */
+ ret = crypto_shash_setkey(tfm, key, keylen);
+ if (ret && ret != -ENOSYS) {
+ pr_err("could not set the key for MAC\n");
+ crypto_free_shash(tfm);
+ kfree(lrng_hash);
+ return ERR_PTR(ret);
+ }
+
+ pr_info("Hash %s allocated\n",
+ lrng_drbg_types[lrng_drbg_type].hash_name);
+
+ return lrng_hash;
+}
+
+static void lrng_drbg_hash_dealloc(void *hash)
+{
+ struct lrng_hash_info *lrng_hash = (struct lrng_hash_info *)hash;
+ struct shash_desc *shash = &lrng_hash->shash;
+ struct crypto_shash *tfm = shash->tfm;
+
+ crypto_free_shash(tfm);
+ kfree(lrng_hash);
+ pr_info("Hash deallocated\n");
+}
+
+static u32 lrng_drbg_hash_digestsize(void *hash)
+{
+ struct lrng_hash_info *lrng_hash = (struct lrng_hash_info *)hash;
+ struct shash_desc *shash = &lrng_hash->shash;
+
+ return crypto_shash_digestsize(shash->tfm);
+}
+
+static int lrng_drbg_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest)
+{
+ struct lrng_hash_info *lrng_hash = (struct lrng_hash_info *)hash;
+ struct shash_desc *shash = &lrng_hash->shash;
+
+ return crypto_shash_digest(shash, inbuf, inbuflen, digest);
+}
+
+static const char *lrng_drbg_name(void)
+{
+ return lrng_drbg_types[lrng_drbg_type].drbg_core;
+}
+
+static const char *lrng_hash_name(void)
+{
+ return lrng_drbg_types[lrng_drbg_type].hash_name;
+}
+
+static const struct lrng_crypto_cb lrng_drbg_crypto_cb = {
+ .lrng_drng_name = lrng_drbg_name,
+ .lrng_hash_name = lrng_hash_name,
+ .lrng_drng_alloc = lrng_drbg_drng_alloc,
+ .lrng_drng_dealloc = lrng_drbg_drng_dealloc,
+ .lrng_drng_seed_helper = lrng_drbg_drng_seed_helper,
+ .lrng_drng_generate_helper = lrng_drbg_drng_generate_helper,
+ .lrng_hash_alloc = lrng_drbg_hash_alloc,
+ .lrng_hash_dealloc = lrng_drbg_hash_dealloc,
+ .lrng_hash_digestsize = lrng_drbg_hash_digestsize,
+ .lrng_hash_buffer = lrng_drbg_hash_buffer,
+};
+
+static int __init lrng_drbg_init(void)
+{
+ if (lrng_drbg_type >= ARRAY_SIZE(lrng_drbg_types)) {
+ pr_err("lrng_drbg_type parameter too large (given %u - max: %lu)",
+ lrng_drbg_type,
+ (unsigned long)ARRAY_SIZE(lrng_drbg_types) - 1);
+ return -EAGAIN;
+ }
+ return lrng_set_drng_cb(&lrng_drbg_crypto_cb);
+}
+
+static void __exit lrng_drbg_exit(void)
+{
+ lrng_set_drng_cb(NULL);
+}
+
+late_initcall(lrng_drbg_init);
+module_exit(lrng_drbg_exit);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Stephan Mueller <[email protected]>");
+MODULE_DESCRIPTION("Linux Random Number Generator - SP800-90A DRBG backend");
--
2.26.2
This patch allows several DRBG functions to be called by the LRNG kernel
code paths outside the drbg.c file.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
crypto/drbg.c | 16 ++++++++++------
include/crypto/drbg.h | 7 +++++++
2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/crypto/drbg.c b/crypto/drbg.c
index e99fe34cfa00..3644e954785a 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -113,7 +113,7 @@
* the SHA256 / AES 256 over other ciphers. Thus, the favored
* DRBGs are the latest entries in this array.
*/
-static const struct drbg_core drbg_cores[] = {
+const struct drbg_core drbg_cores[] = {
#ifdef CONFIG_CRYPTO_DRBG_CTR
{
.flags = DRBG_CTR | DRBG_STRENGTH128,
@@ -190,6 +190,7 @@ static const struct drbg_core drbg_cores[] = {
},
#endif /* CONFIG_CRYPTO_DRBG_HMAC */
};
+EXPORT_SYMBOL(drbg_cores);
static int drbg_uninstantiate(struct drbg_state *drbg);
@@ -205,7 +206,7 @@ static int drbg_uninstantiate(struct drbg_state *drbg);
* Return: normalized strength in *bytes* value or 32 as default
* to counter programming errors
*/
-static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
+unsigned short drbg_sec_strength(drbg_flag_t flags)
{
switch (flags & DRBG_STRENGTH_MASK) {
case DRBG_STRENGTH128:
@@ -218,6 +219,7 @@ static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
return 32;
}
}
+EXPORT_SYMBOL(drbg_sec_strength);
/*
* FIPS 140-2 continuous self test for the noise source
@@ -1214,7 +1216,7 @@ static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
}
/* Free all substructures in a DRBG state without the DRBG state structure */
-static inline void drbg_dealloc_state(struct drbg_state *drbg)
+void drbg_dealloc_state(struct drbg_state *drbg)
{
if (!drbg)
return;
@@ -1235,12 +1237,13 @@ static inline void drbg_dealloc_state(struct drbg_state *drbg)
drbg->fips_primed = false;
}
}
+EXPORT_SYMBOL(drbg_dealloc_state);
/*
* Allocate all sub-structures for a DRBG state.
* The DRBG state structure must already be allocated.
*/
-static inline int drbg_alloc_state(struct drbg_state *drbg)
+int drbg_alloc_state(struct drbg_state *drbg)
{
int ret = -ENOMEM;
unsigned int sb_size = 0;
@@ -1321,6 +1324,7 @@ static inline int drbg_alloc_state(struct drbg_state *drbg)
drbg_dealloc_state(drbg);
return ret;
}
+EXPORT_SYMBOL(drbg_alloc_state);
/*************************************************************************
* DRBG interface functions
@@ -1890,8 +1894,7 @@ static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
*
* return: flags
*/
-static inline void drbg_convert_tfm_core(const char *cra_driver_name,
- int *coreref, bool *pr)
+void drbg_convert_tfm_core(const char *cra_driver_name, int *coreref, bool *pr)
{
int i = 0;
size_t start = 0;
@@ -1918,6 +1921,7 @@ static inline void drbg_convert_tfm_core(const char *cra_driver_name,
}
}
}
+EXPORT_SYMBOL(drbg_convert_tfm_core);
static int drbg_kcapi_init(struct crypto_tfm *tfm)
{
diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h
index c4165126937e..71d53e028e6d 100644
--- a/include/crypto/drbg.h
+++ b/include/crypto/drbg.h
@@ -278,4 +278,11 @@ enum drbg_prefixes {
DRBG_PREFIX3
};
+extern int drbg_alloc_state(struct drbg_state *drbg);
+extern void drbg_dealloc_state(struct drbg_state *drbg);
+extern void drbg_convert_tfm_core(const char *cra_driver_name, int *coreref,
+ bool *pr);
+extern const struct drbg_core drbg_cores[];
+extern unsigned short drbg_sec_strength(drbg_flag_t flags);
+
#endif /* _DRBG_H */
--
2.26.2
In an effort to provide a flexible implementation for a random number
generator that also delivers entropy during early boot time, allows
replacement of the deterministic random number generation mechanism,
implement the various components in separate code for easier
maintenance, and provide compliance to SP800-90[A|B|C], introduce
the Linux Random Number Generator (LRNG) framework.
The general design is as follows. Additional implementation details
are given in [1]. The LRNG consists of the following components:
1. The LRNG implements a DRNG. The DRNG always generates the
requested amount of output. When using the SP800-90A terminology
it operates without prediction resistance. The secondary DRNG
maintains a counter of how many bytes were generated since last
re-seed and a timer of the elapsed time since last re-seed. If either
the counter or the timer reaches a threshold, the secondary DRNG is
seeded from the entropy pool.
In case the Linux kernel detects a NUMA system, one secondary DRNG
instance per NUMA node is maintained.
2. The DRNG is seeded by concatenating the data from the
following sources:
(a) the output of the entropy pool,
(b) the Jitter RNG if available and enabled, and
(c) the CPU-based noise source such as Intel RDRAND if available and
enabled.
The entropy estimate of the data of all noise sources are added to
form the entropy estimate of the data used to seed the DRNG with.
The LRNG ensures, however, that the DRNG after seeding is at
maximum the security strength of the DRNG.
The LRNG is designed such that none of these noise sources can dominate
the other noise sources to provide seed data to the DRNG during due to
the following:
(a) During boot time, the amount of received interrupts are the trigger
points to (re)seed the DRNG.
(b) At runtime, the available entropy from the slow noise source is
concatenated with a pre-defined amount of data from the fast noise
sources. In addition, each DRNG reseed operation triggers external
noise source providers to deliver one block of data.
3. The entropy pool accumulates entropy obtained from certain events,
which will henceforth be collectively called "slow noise sources".
The entropy pool collects noise data from slow noise sources. Any data
received by the LRNG from the slow noise sources is inserted into the
entropy pool using an LFSR with a primitive and irreducible polynomial.
The following sources of entropy are used:
(a) When an interrupt occurs, the high-resolution time stamp is mixed
into the LFSR. This time stamp is credited with heuristically implied
entropy.
(b) HID event data like the key stroke or the mouse coordinates are
mixed into the LFSR. This data is not credited with entropy by the LRNG.
(c) Device drivers may provide data that is mixed into the LFSR. This
data is not credited with entropy by the LRNG.
(d) After the entropy pool is ``read'' by the DRNG, the data
used to seed the DRNG is mixed back into the entropy pool to
stir the pool. This data is not credited with entropy by the LRNG.
Any data provided from user space by either writing to /dev/random,
/dev/urandom or the IOCTL of RNDADDENTROPY on both device files
are always injected into the entropy pool.
In addition, when a hardware random number generator covered by the
Linux kernel HW generator framework wants to deliver random numbers,
it is injected into the entropy pool as well. HW generator noise source
is handled separately from the other noise source due to the fact that
the HW generator framework may decide by itself when to deliver data
whereas the other noise sources always requested for data driven by the
LRNG operation. Similarly any user space provided data is inserted into
the entropy pool.
When the DRNG requires data from the entropy pool, the entire
entropy pool is processed with an SP800-90A section 10.3.1 compliant
hash_df function to generate random numbers.
To speed up the interrupt handling code of the LRNG, the time stamp
collected for an interrupt event is truncated to the 8 least
significant bits. 64 truncated time stamps are concatenated and then
jointly inserted into the LFSR. During boot time, until the fully seeded
stage is reached, each time stamp with its 32 least significant bits is
inserted into the LFSR at the time of arrival.
The LRNG allows the DRNG mechanism to be changed at runtime. Per default,
a ChaCha20-based DRNG is used. The ChaCha20-DRNG implemented for the
LRNG is also provided as a stand-alone user space deterministic random
number generator. The LRNG also offers an SP800-90A DRBG based on the
Linux kernel crypto API DRBG implementation.
The processing of entropic data from the noise source before injecting
them into the DRNG is performed with the following mathematical
operations:
1. LFSR: The 8 least significant bits of the time stamp data received
from the interrupts are processed with an LFSR. That LFSR is implemented
identically to the LSFR used in the existing /dev/random implementation
except that it is capable of processing an entire word and that a
different polynomial is used. The reason for the different polynomial
is performance in a performance sensitive code section, the interrupt
handler. The chosen polynomials have 4 taps. Also, this LFSR-approach
is used in the OpenBSD /dev/random equivalent.
2. Concatenation: The temporary seed buffer used to seed the DRNG is
a concatenation of parts of the entropy pool data, and the CPU noise
source output.
The DRNG always tries to seed itself with 256 bits of entropy, except
during boot. In any case, if the noise sources cannot deliver that
amount, the available entropy is used and the DRNG keeps track on how
much entropy it was seeded with. The entropy implied by the LRNG
available in the entropy pool may be too conservative. To ensure
that during boot time all available entropy from the entropy pool is
transferred to the DRNG, the hash_df function always generates 256
data bits during boot to seed the DRNG. During boot, the DRNG is
seeded as follows:
1. The DRNG is reseeded from the entropy pool and potentially the fast
noise sources if the entropy pool has collected at least 32 bits of
entropy from the interrupt noise source. The goal of this step is to
ensure that the DRNG receives some initial entropy as early as
possible. In addition it receives the entropy available from
the fast noise sources.
2. The DRNG is reseeded from the entropy pool and potentially the fast
noise sources if all noise sources collectively can provide at least
128 bits of entropy.
3. The DRNG is reseeded from the entropy pool and potentially the fast
noise sources if all noise sources collectivel can provide at least 256
bits.
At the time of the reseeding steps, the DRNG requests as much entropy as
is available in order to skip certain steps and reach the seeding level
of 256 bits. This may imply that one or more of the aforementioned steps
are skipped.
In all listed steps, the DRNG is (re)seeded with a number of random
bytes from the entropy pool that is at most the amount of entropy
present in the entropy pool. This means that when the entropy pool
contains 128 or 256 bits of entropy, the DRNG is seeded with that
amount of entropy as well.
Before the DRNG is seeded with 256 bits of entropy in step 3,
requests of random data from /dev/random are not processed.
The hash_df operation providing random data from the entropy pool will
always require that all entropy sources collectively can deliver at
least 129 entropy bits as configured with (128 bits of entropy for
seeding plus one bit of entropy that is lost with the post
processing as defined in SP800-90B).
The DRNG operates as deterministic random number generator with the
following properties:
* The maximum number of random bytes that can be generated with one
DRNG generate operation is limited to 4096 bytes. When longer random
numbers are requested, multiple DRNG generate operations are performed.
The ChaCha20 DRNG as well as the SP800-90A DRBGs implement an update of
their state after completing a generate request for backtracking
resistance.
* The secondary DRNG is reseeded with whatever entropy is available –
in the worst case where no additional entropy can be provided by the
noise sources, the DRNG is not re-seeded and continues its operation
to try to reseed again after again the expiry of one of these thresholds:
- If the last reseeding of the secondary DRNG is more than 600 seconds
ago, or
- 2^20 DRNG generate operations are performed, whatever comes first, or
- the secondary DRNG is forced to reseed before the next generation of
random numbers if data has been injected into the LRNG by writing data
into /dev/random or /dev/urandom.
The chosen values prevent high-volume requests from user space to cause
frequent reseeding operations which drag down the performance of the
DRNG.
With the automatic reseeding after 600 seconds, the LRNG is triggered
to reseed itself before the first request after a suspend that put the
hardware to sleep for longer than 600 seconds.
The LRNG uses the following runtime memory using the currently
smallest configuration:
* 576 bytes (512 bytes for the entropy pool and 64 for the entropy pool
meta data) for the entropy pool management
* 64 bytes per CPU for the time stamp array
To support smaller devices including IoT environments, this patch
allows reducing the runtime memory footprint of the LRNG at compile
time by selecting smaller entropy pool sizes.
The entropy pool has support for sizes of 256, 128 and 64 bytes supported
by primitive and irreducible polynomials.
The time stamp array is reduced to one atomic_t variable per CPU, i.e.
4 bytes when CONFIG_BASE_SMALL is selected during kernel
configuration. This implies that after the receipt of 4 interrupts on
one CPU, the data is injected into the LFSR. Depending on the behavior
of the CPU caches, this may imply that the average interrupt handler
execution time increases a bit, since instead of injecting 8 atomic_t
values at one given time into the LFSR, only one is processed which
may incur cache misses.
When selecting the compilation of a kernel for a small environment,
prevent the allocation of a buffer up to 4096 bytes to serve user space
requests. In this case, the stack variable of 64 bytes is used to serve
all user space requests.
The LRNG has the following properties:
* internal noise source: interrupts timing with fast boot time seeding
* high performance of interrupt handling code: The LRNG impact on the
interrupt handling has been reduced to a minimum. On one example
system, the LRNG interrupt handling code executes within an average
of 65 cycles whereas the existing /dev/random on the same device
takes about 97 cycles when measuring the execution time of
add_interrupt_randomness().
* lockless LFSR to collect raw entropy supporing concurrency-free
use of massive parallel systems
* use of standalone ChaCha20 based RNG with the option to use a
different DRNG selectable at compile time
* "atomic" seeding of secondary DRBG to ensure full entropy transport
* instantiate one DRNG per NUMA node
* support for runtime switchable output DRNGs
* use of only well-defined entropy-preserving operations to collect,
compress and forward entropy: concatenation, LFSR, SP800-90A hash_df
function
* compile-time selectable entropy pool size: the choice also
uses the applicable LFSR polynomial to maintain the entropy pool
size
* support of small systems by allowing the reduction of the
runtime memory needs
Further details including the rationale for the design choices and
properties of the LRNG together with testing is provided at [1].
In addition, the documentation explains the conducted regression
tests to verify that the LRNG is API and ABI compatible with the
existing /dev/random implementation.
[1] https://www.chronox.de/lrng.html
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Mathematical aspects Reviewed-by: "Peter, Matthias" <[email protected]>
Reviewed-by: Marcelo Henrique Cerri <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtmüller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
MAINTAINERS | 7 +
drivers/char/Kconfig | 2 +
drivers/char/Makefile | 9 +-
drivers/char/lrng/Kconfig | 68 +++
drivers/char/lrng/Makefile | 9 +
drivers/char/lrng/lrng_archrandom.c | 93 ++++
drivers/char/lrng/lrng_aux.c | 136 ++++++
drivers/char/lrng/lrng_chacha20.c | 321 ++++++++++++++
drivers/char/lrng/lrng_chacha20.h | 29 ++
drivers/char/lrng/lrng_drng.c | 409 +++++++++++++++++
drivers/char/lrng/lrng_interfaces.c | 652 ++++++++++++++++++++++++++++
drivers/char/lrng/lrng_internal.h | 342 +++++++++++++++
drivers/char/lrng/lrng_lfsr.h | 152 +++++++
drivers/char/lrng/lrng_pool.c | 589 +++++++++++++++++++++++++
drivers/char/lrng/lrng_sw_noise.c | 155 +++++++
drivers/char/lrng/lrng_sw_noise.h | 57 +++
include/linux/lrng.h | 63 +++
17 files changed, 3092 insertions(+), 1 deletion(-)
create mode 100644 drivers/char/lrng/Kconfig
create mode 100644 drivers/char/lrng/Makefile
create mode 100644 drivers/char/lrng/lrng_archrandom.c
create mode 100644 drivers/char/lrng/lrng_aux.c
create mode 100644 drivers/char/lrng/lrng_chacha20.c
create mode 100644 drivers/char/lrng/lrng_chacha20.h
create mode 100644 drivers/char/lrng/lrng_drng.c
create mode 100644 drivers/char/lrng/lrng_interfaces.c
create mode 100644 drivers/char/lrng/lrng_internal.h
create mode 100644 drivers/char/lrng/lrng_lfsr.h
create mode 100644 drivers/char/lrng/lrng_pool.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.h
create mode 100644 include/linux/lrng.h
diff --git a/MAINTAINERS b/MAINTAINERS
index deaafb617361..74f6fd1ba1ec 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10084,6 +10084,13 @@ F: Documentation/litmus-tests/
F: Documentation/memory-barriers.txt
F: tools/memory-model/
+LINUX RANDOM NUMBER GENERATOR (LRNG) DRIVER
+M: Stephan Mueller <[email protected]>
+S: Maintained
+W: https://www.chronox.de/lrng.html
+F: drivers/char/lrng/*
+F: include/linux/lrng.h
+
LIS3LV02D ACCELEROMETER DRIVER
M: Eric Piel <[email protected]>
S: Maintained
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index b1bd336761b1..8a5b8a2db2c7 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -470,6 +470,8 @@ config ADI
and SSM (Silicon Secured Memory). Intended consumers of this
driver include crash and makedumpfile.
+source "drivers/char/lrng/Kconfig"
+
endmenu
config RANDOM_TRUST_CPU
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index ffce287ef415..2110d3e28cf2 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -3,7 +3,14 @@
# Makefile for the kernel character device drivers.
#
-obj-y += mem.o random.o
+obj-y += mem.o
+
+ifeq ($(CONFIG_LRNG),y)
+ obj-y += lrng/
+else
+ obj-y += random.o
+endif
+
obj-$(CONFIG_TTY_PRINTK) += ttyprintk.o
obj-y += misc.o
obj-$(CONFIG_ATARI_DSP56K) += dsp56k.o
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
new file mode 100644
index 000000000000..059b21d9728c
--- /dev/null
+++ b/drivers/char/lrng/Kconfig
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Linux Random Number Generator configuration
+#
+
+menuconfig LRNG
+ bool "Linux Random Number Generator"
+ select CRYPTO_LIB_SHA256 if CRYPTO
+ help
+ The Linux Random Number Generator (LRNG) is the replacement
+ of the existing /dev/random provided with drivers/char/random.c.
+ It generates entropy from different noise sources and
+ delivers significant entropy during boot.
+
+if LRNG
+
+choice
+ prompt "LRNG Entropy Pool Size"
+ default LRNG_POOL_SIZE_4096
+ help
+ Select the size of the LRNG entropy pool. The size of the
+ entropy pool is relevant for the amount of entropy that
+ the LRNG can maintain as a maximum. The larger the size
+ of the entropy pool is the more entropy can be maintained
+ but the less often older entropic values are overwritten
+ with new entropy.
+
+ config LRNG_POOL_SIZE_512
+ bool "512 bits"
+
+ config LRNG_POOL_SIZE_1024
+ bool "1024 bits"
+
+ config LRNG_POOL_SIZE_2048
+ bool "2048 bits"
+
+ config LRNG_POOL_SIZE_4096
+ bool "4096 bits (default)"
+
+ config LRNG_POOL_SIZE_8192
+ bool "8192 bits"
+
+ config LRNG_POOL_SIZE_16384
+ bool "16384 bits"
+
+ config LRNG_POOL_SIZE_32768
+ bool "32768 bits"
+
+ config LRNG_POOL_SIZE_65536
+ bool "65536 bits"
+
+ config LRNG_POOL_SIZE_131072
+ bool "131072 bits"
+endchoice
+
+config LRNG_POOL_SIZE
+ int
+ default 0 if LRNG_POOL_SIZE_512
+ default 1 if LRNG_POOL_SIZE_1024
+ default 2 if LRNG_POOL_SIZE_2048
+ default 3 if LRNG_POOL_SIZE_4096
+ default 4 if LRNG_POOL_SIZE_8192
+ default 5 if LRNG_POOL_SIZE_16384
+ default 6 if LRNG_POOL_SIZE_32768
+ default 7 if LRNG_POOL_SIZE_65536
+ default 8 if LRNG_POOL_SIZE_131072
+
+endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
new file mode 100644
index 000000000000..1d2a0211973d
--- /dev/null
+++ b/drivers/char/lrng/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux Random Number Generator.
+#
+
+obj-y += lrng_pool.o lrng_aux.o \
+ lrng_sw_noise.o lrng_archrandom.o \
+ lrng_drng.o lrng_chacha20.o \
+ lrng_interfaces.o \
diff --git a/drivers/char/lrng/lrng_archrandom.c b/drivers/char/lrng/lrng_archrandom.c
new file mode 100644
index 000000000000..5e81c4e856d5
--- /dev/null
+++ b/drivers/char/lrng/lrng_archrandom.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Fast Noise Source: CPU-based noise source
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/random.h>
+
+#include "lrng_internal.h"
+
+/*
+ * Estimated entropy of data is a 32th of LRNG_DRNG_SECURITY_STRENGTH_BITS.
+ * As we have no ability to review the implementation of those noise sources,
+ * it is prudent to have a conservative estimate here.
+ */
+#define LRNG_ARCHRANDOM_DEFAULT_STRENGTH (LRNG_DRNG_SECURITY_STRENGTH_BITS>>5)
+#define LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH LRNG_DRNG_SECURITY_STRENGTH_BITS
+#ifdef CONFIG_RANDOM_TRUST_CPU
+static u32 archrandom = LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH;
+#else
+static u32 archrandom = LRNG_ARCHRANDOM_DEFAULT_STRENGTH;
+#endif
+module_param(archrandom, uint, 0644);
+MODULE_PARM_DESC(archrandom, "Entropy in bits of 256 data bits from CPU noise source (e.g. RDRAND)");
+
+static int __init lrng_parse_trust_cpu(char *arg)
+{
+ int ret;
+ bool trust_cpu = false;
+
+ ret = kstrtobool(arg, &trust_cpu);
+ if (ret)
+ return ret;
+
+ if (trust_cpu)
+ archrandom = LRNG_ARCHRANDOM_TRUST_CPU_STRENGTH;
+ else
+ archrandom = LRNG_ARCHRANDOM_DEFAULT_STRENGTH;
+
+ return 0;
+}
+early_param("random.trust_cpu", lrng_parse_trust_cpu);
+
+/**
+ * lrng_get_arch() - Get CPU noise source entropy
+ *
+ * @outbuf: buffer to store entropy of size LRNG_DRNG_SECURITY_STRENGTH_BYTES
+ *
+ * Return:
+ * * > 0 on success where value provides the added entropy in bits
+ * * 0 if no fast source was available
+ */
+u32 lrng_get_arch(u8 *outbuf)
+{
+ u32 i, ent_bits = archrandom;
+
+ /* operate on full blocks */
+ BUILD_BUG_ON(LRNG_DRNG_SECURITY_STRENGTH_BYTES % sizeof(unsigned long));
+ /* ensure we have aligned buffers */
+ BUILD_BUG_ON(LRNG_KCAPI_ALIGN % sizeof(unsigned long));
+
+ if (!ent_bits)
+ return 0;
+
+ for (i = 0; i < LRNG_DRNG_SECURITY_STRENGTH_BYTES;
+ i += sizeof(unsigned long)) {
+ if (!arch_get_random_seed_long((unsigned long *)(outbuf + i)) &&
+ !arch_get_random_long((unsigned long *)(outbuf + i))) {
+ archrandom = 0;
+ return 0;
+ }
+ }
+
+ /* Obtain entropy statement -- cap entropy to buffer size in bits */
+ ent_bits = min_t(u32, ent_bits, LRNG_DRNG_SECURITY_STRENGTH_BITS);
+ pr_debug("obtained %u bits of entropy from CPU RNG noise source\n",
+ ent_bits);
+ return ent_bits;
+}
+
+u32 lrng_slow_noise_req_entropy(u32 required_entropy_bits)
+{
+ u32 arch_ent_bits = min_t(u32, archrandom,
+ LRNG_DRNG_SECURITY_STRENGTH_BITS);
+ u32 fast_noise_entropy = arch_ent_bits + lrng_jent_entropylevel();
+
+ if (fast_noise_entropy > required_entropy_bits)
+ return 0;
+ return (required_entropy_bits - fast_noise_entropy);
+}
diff --git a/drivers/char/lrng/lrng_aux.c b/drivers/char/lrng/lrng_aux.c
new file mode 100644
index 000000000000..9f46c5707517
--- /dev/null
+++ b/drivers/char/lrng/lrng_aux.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG auxiliary interfaces
+ *
+ * Copyright (C) 2019 Stephan Mueller <[email protected]>
+ * Copyright (C) 2017 Jason A. Donenfeld <[email protected]>. All
+ * Rights Reserved.
+ * Copyright (C) 2016 Jason Cooper <[email protected]>
+ */
+
+#include <linux/mm.h>
+#include <linux/random.h>
+
+#include "lrng_internal.h"
+
+struct batched_entropy {
+ union {
+ u64 entropy_u64[LRNG_DRNG_BLOCKSIZE / sizeof(u64)];
+ u32 entropy_u32[LRNG_DRNG_BLOCKSIZE / sizeof(u32)];
+ };
+ unsigned int position;
+ spinlock_t batch_lock;
+};
+
+/*
+ * Get a random word for internal kernel use only. The quality of the random
+ * number is as good as /dev/urandom, but there is no backtrack protection,
+ * with the goal of being quite fast and not depleting entropy.
+ */
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64) = {
+ .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u64.lock),
+};
+
+u64 get_random_u64(void)
+{
+ u64 ret;
+ unsigned long flags;
+ struct batched_entropy *batch;
+
+ lrng_debug_report_seedlevel("get_random_u64");
+
+ batch = raw_cpu_ptr(&batched_entropy_u64);
+ spin_lock_irqsave(&batch->batch_lock, flags);
+ if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) {
+ lrng_drng_get_atomic((u8 *)batch->entropy_u64,
+ LRNG_DRNG_BLOCKSIZE);
+ batch->position = 0;
+ }
+ ret = batch->entropy_u64[batch->position++];
+ spin_unlock_irqrestore(&batch->batch_lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(get_random_u64);
+
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32) = {
+ .batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u32.lock),
+};
+
+u32 get_random_u32(void)
+{
+ u32 ret;
+ unsigned long flags;
+ struct batched_entropy *batch;
+
+ lrng_debug_report_seedlevel("get_random_u32");
+
+ batch = raw_cpu_ptr(&batched_entropy_u32);
+ spin_lock_irqsave(&batch->batch_lock, flags);
+ if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) {
+ lrng_drng_get_atomic((u8 *)batch->entropy_u32,
+ LRNG_DRNG_BLOCKSIZE);
+ batch->position = 0;
+ }
+ ret = batch->entropy_u32[batch->position++];
+ spin_unlock_irqrestore(&batch->batch_lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(get_random_u32);
+
+/*
+ * It's important to invalidate all potential batched entropy that might
+ * be stored before the crng is initialized, which we can do lazily by
+ * simply resetting the counter to zero so that it's re-extracted on the
+ * next usage.
+ */
+void invalidate_batched_entropy(void)
+{
+ int cpu;
+ unsigned long flags;
+
+ for_each_possible_cpu(cpu) {
+ struct batched_entropy *batched_entropy;
+
+ batched_entropy = per_cpu_ptr(&batched_entropy_u32, cpu);
+ spin_lock_irqsave(&batched_entropy->batch_lock, flags);
+ batched_entropy->position = 0;
+ spin_unlock(&batched_entropy->batch_lock);
+
+ batched_entropy = per_cpu_ptr(&batched_entropy_u64, cpu);
+ spin_lock(&batched_entropy->batch_lock);
+ batched_entropy->position = 0;
+ spin_unlock_irqrestore(&batched_entropy->batch_lock, flags);
+ }
+}
+
+/**
+ * randomize_page - Generate a random, page aligned address
+ * @start: The smallest acceptable address the caller will take.
+ * @range: The size of the area, starting at @start, within which the
+ * random address must fall.
+ *
+ * If @start + @range would overflow, @range is capped.
+ *
+ * NOTE: Historical use of randomize_range, which this replaces, presumed that
+ * @start was already page aligned. We now align it regardless.
+ *
+ * Return: A page aligned address within [start, start + range). On error,
+ * @start is returned.
+ */
+unsigned long randomize_page(unsigned long start, unsigned long range)
+{
+ if (!PAGE_ALIGNED(start)) {
+ range -= PAGE_ALIGN(start) - start;
+ start = PAGE_ALIGN(start);
+ }
+
+ if (start > ULONG_MAX - range)
+ range = ULONG_MAX - start;
+
+ range >>= PAGE_SHIFT;
+
+ if (range == 0)
+ return start;
+
+ return start + (get_random_long() % range << PAGE_SHIFT);
+}
diff --git a/drivers/char/lrng/lrng_chacha20.c b/drivers/char/lrng/lrng_chacha20.c
new file mode 100644
index 000000000000..8c475c286810
--- /dev/null
+++ b/drivers/char/lrng/lrng_chacha20.c
@@ -0,0 +1,321 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Backend for the LRNG providing the cryptographic primitives using
+ * ChaCha20 cipher implementations.
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <crypto/chacha.h>
+#include <crypto/sha.h>
+#include <linux/lrng.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+
+#include "lrng_chacha20.h"
+#include "lrng_internal.h"
+
+/******************************* ChaCha20 DRNG *******************************/
+
+#define CHACHA_BLOCK_WORDS (CHACHA_BLOCK_SIZE / sizeof(u32))
+
+struct chacha20_state {
+ struct chacha20_block block;
+};
+
+/*
+ * Have a static memory blocks for the ChaCha20 DRNG instance to avoid calling
+ * kmalloc too early in the boot cycle. For subsequent allocation requests,
+ * such as per-NUMA-node DRNG instances, kmalloc will be used.
+ */
+struct chacha20_state chacha20;
+
+/**
+ * Update of the ChaCha20 state by either using an unused buffer part or by
+ * generating one ChaCha20 block which is half of the state of the ChaCha20.
+ * The block is XORed into the key part of the state. This shall ensure
+ * backtracking resistance as well as a proper mix of the ChaCha20 state once
+ * the key is injected.
+ */
+static void lrng_chacha20_update(struct chacha20_state *chacha20_state,
+ __le32 *buf, u32 used_words)
+{
+ struct chacha20_block *chacha20 = &chacha20_state->block;
+ u32 i;
+ __le32 tmp[CHACHA_BLOCK_WORDS];
+
+ BUILD_BUG_ON(sizeof(struct chacha20_block) != CHACHA_BLOCK_SIZE);
+ BUILD_BUG_ON(CHACHA_BLOCK_SIZE != 2 * CHACHA_KEY_SIZE);
+
+ if (used_words > CHACHA_KEY_SIZE_WORDS) {
+ chacha20_block(&chacha20->constants[0], (u8 *)tmp);
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++)
+ chacha20->key.u[i] ^= le32_to_cpu(tmp[i]);
+ memzero_explicit(tmp, sizeof(tmp));
+ } else {
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++)
+ chacha20->key.u[i] ^= le32_to_cpu(buf[i + used_words]);
+ }
+
+ /* Deterministic increment of nonce as required in RFC 7539 chapter 4 */
+ chacha20->nonce[0]++;
+ if (chacha20->nonce[0] == 0)
+ chacha20->nonce[1]++;
+ if (chacha20->nonce[1] == 0)
+ chacha20->nonce[2]++;
+
+ /* Leave counter untouched as it is start value is undefined in RFC */
+}
+
+/*
+ * Seed the ChaCha20 DRNG by injecting the input data into the key part of
+ * the ChaCha20 state. If the input data is longer than the ChaCha20 key size,
+ * perform a ChaCha20 operation after processing of key size input data.
+ * This operation shall spread out the entropy into the ChaCha20 state before
+ * new entropy is injected into the key part.
+ */
+static int lrng_cc20_drng_seed_helper(void *drng, const u8 *inbuf, u32 inbuflen)
+{
+ struct chacha20_state *chacha20_state = (struct chacha20_state *)drng;
+ struct chacha20_block *chacha20 = &chacha20_state->block;
+
+ while (inbuflen) {
+ u32 i, todo = min_t(u32, inbuflen, CHACHA_KEY_SIZE);
+
+ for (i = 0; i < todo; i++)
+ chacha20->key.b[i] ^= inbuf[i];
+
+ /* Break potential dependencies between the inbuf key blocks */
+ lrng_chacha20_update(chacha20_state, NULL,
+ CHACHA_BLOCK_WORDS);
+ inbuf += todo;
+ inbuflen -= todo;
+ }
+
+ return 0;
+}
+
+/*
+ * Chacha20 DRNG generation of random numbers: the stream output of ChaCha20
+ * is the random number. After the completion of the generation of the
+ * stream, the entire ChaCha20 state is updated.
+ *
+ * Note, as the ChaCha20 implements a 32 bit counter, we must ensure
+ * that this function is only invoked for at most 2^32 - 1 ChaCha20 blocks
+ * before a reseed or an update happens. This is ensured by the variable
+ * outbuflen which is a 32 bit integer defining the number of bytes to be
+ * generated by the ChaCha20 DRNG. At the end of this function, an update
+ * operation is invoked which implies that the 32 bit counter will never be
+ * overflown in this implementation.
+ */
+static int lrng_cc20_drng_generate_helper(void *drng, u8 *outbuf, u32 outbuflen)
+{
+ struct chacha20_state *chacha20_state = (struct chacha20_state *)drng;
+ struct chacha20_block *chacha20 = &chacha20_state->block;
+ __le32 aligned_buf[CHACHA_BLOCK_WORDS];
+ u32 ret = outbuflen, used = CHACHA_BLOCK_WORDS;
+ int zeroize_buf = 0;
+
+ while (outbuflen >= CHACHA_BLOCK_SIZE) {
+ chacha20_block(&chacha20->constants[0], outbuf);
+ outbuf += CHACHA_BLOCK_SIZE;
+ outbuflen -= CHACHA_BLOCK_SIZE;
+ }
+
+ if (outbuflen) {
+ chacha20_block(&chacha20->constants[0], (u8 *)aligned_buf);
+ memcpy(outbuf, aligned_buf, outbuflen);
+ used = ((outbuflen + sizeof(aligned_buf[0]) - 1) /
+ sizeof(aligned_buf[0]));
+ zeroize_buf = 1;
+ }
+
+ lrng_chacha20_update(chacha20_state, aligned_buf, used);
+
+ if (zeroize_buf)
+ memzero_explicit(aligned_buf, sizeof(aligned_buf));
+
+ return ret;
+}
+
+void lrng_cc20_init_state(struct chacha20_state *state)
+{
+ struct chacha20_block *chacha20 = &state->block;
+ unsigned long v;
+ u32 i;
+
+ lrng_cc20_init_rfc7539(chacha20);
+
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) {
+ chacha20->key.u[i] ^= jiffies;
+ chacha20->key.u[i] ^= random_get_entropy();
+ if (arch_get_random_seed_long(&v) || arch_get_random_long(&v))
+ chacha20->key.u[i] ^= v;
+ }
+
+ for (i = 0; i < 3; i++) {
+ chacha20->nonce[i] ^= jiffies;
+ chacha20->nonce[i] ^= random_get_entropy();
+ if (arch_get_random_seed_long(&v) || arch_get_random_long(&v))
+ chacha20->nonce[i] ^= v;
+ }
+
+ lrng_chacha20_update(state, NULL, CHACHA_BLOCK_WORDS);
+ pr_info("ChaCha20 core initialized\n");
+}
+
+void __init lrng_cc20_init_state_boot(struct chacha20_state *state)
+{
+ struct chacha20_block *chacha20 = &state->block;
+ unsigned long v;
+ u32 i;
+
+ for (i = 0; i < CHACHA_KEY_SIZE_WORDS; i++) {
+ if (arch_get_random_seed_long_early(&v) ||
+ arch_get_random_long_early(&v))
+ chacha20->key.u[i] ^= v;
+ }
+
+ for (i = 0; i < 3; i++) {
+ if (arch_get_random_seed_long_early(&v) ||
+ arch_get_random_long_early(&v))
+ chacha20->nonce[i] ^= v;
+ }
+
+ lrng_chacha20_update(state, NULL, CHACHA_BLOCK_WORDS);
+}
+
+/*
+ * Allocation of the DRNG state
+ */
+static void *lrng_cc20_drng_alloc(u32 sec_strength)
+{
+ struct chacha20_state *state = NULL;
+
+ if (sec_strength > CHACHA_KEY_SIZE) {
+ pr_err("Security strength of ChaCha20 DRNG (%u bits) lower than requested by LRNG (%u bits)\n",
+ CHACHA_KEY_SIZE * 8, sec_strength * 8);
+ return ERR_PTR(-EINVAL);
+ }
+ if (sec_strength < CHACHA_KEY_SIZE)
+ pr_warn("Security strength of ChaCha20 DRNG (%u bits) higher than requested by LRNG (%u bits)\n",
+ CHACHA_KEY_SIZE * 8, sec_strength * 8);
+
+ state = kmalloc(sizeof(struct chacha20_state), GFP_KERNEL);
+ if (!state)
+ return ERR_PTR(-ENOMEM);
+ pr_debug("memory for ChaCha20 core allocated\n");
+
+ lrng_cc20_init_state(state);
+
+ return state;
+}
+
+static void lrng_cc20_drng_dealloc(void *drng)
+{
+ struct chacha20_state *chacha20_state = (struct chacha20_state *)drng;
+
+ if (drng == &chacha20) {
+ memzero_explicit(chacha20_state, sizeof(*chacha20_state));
+ pr_debug("static ChaCha20 core zeroized\n");
+ return;
+ }
+
+ pr_debug("ChaCha20 core zeroized and freed\n");
+ kzfree(chacha20_state);
+}
+
+/******************************* Hash Operation *******************************/
+
+#ifdef CONFIG_CRYPTO_LIB_SHA256
+
+static u32 lrng_cc20_hash_digestsize(void *hash)
+{
+ return SHA256_DIGEST_SIZE;
+}
+
+static int lrng_cc20_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest)
+{
+ struct sha256_state sctx;
+
+ sha256_init(&sctx);
+ sha256_update(&sctx, inbuf, inbuflen);
+ sha256_final(&sctx, digest);
+
+ /* Zeroization of sctx is performed by sha256_final */
+
+ return 0;
+}
+
+static const char *lrng_cc20_hash_name(void)
+{
+ const char *cc20_hash_name = "SHA-256";
+ return cc20_hash_name;
+}
+
+#else /* CONFIG_CRYPTO_LIB_SHA256 */
+
+/*
+ * If the SHA-256 support is not compiled, we fall back to SHA-1 that is always
+ * compiled and present in the kernel.
+ */
+static u32 lrng_cc20_hash_digestsize(void *hash)
+{
+ return (SHA1_DIGEST_WORDS * sizeof(u32));
+}
+
+static int lrng_cc20_hash_buffer(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest)
+{
+ u32 i;
+ u32 workspace[SHA1_WORKSPACE_WORDS];
+
+ WARN_ON(inbuflen % (SHA1_WORKSPACE_WORDS * sizeof(u32)));
+
+ sha1_init((u32 *)digest);
+ for (i = 0; i < inbuflen; i += (SHA1_WORKSPACE_WORDS * sizeof(u32)))
+ sha1_transform((u32 *)digest, (inbuf + i), workspace);
+ memzero_explicit(workspace, sizeof(workspace));
+
+ return 0;
+}
+
+static const char *lrng_cc20_hash_name(void)
+{
+ const char *cc20_hash_name = "SHA-1";
+ return cc20_hash_name;
+}
+
+#endif /* CONFIG_CRYPTO_LIB_SHA256 */
+
+static void *lrng_cc20_hash_alloc(const u8 *key, u32 keylen)
+{
+ pr_info("Hash %s allocated\n", lrng_cc20_hash_name());
+ return NULL;
+}
+
+static void lrng_cc20_hash_dealloc(void *hash)
+{
+}
+
+static const char *lrng_cc20_drng_name(void)
+{
+ const char *cc20_drng_name = "ChaCha20 DRNG";
+ return cc20_drng_name;
+}
+
+const struct lrng_crypto_cb lrng_cc20_crypto_cb = {
+ .lrng_drng_name = lrng_cc20_drng_name,
+ .lrng_hash_name = lrng_cc20_hash_name,
+ .lrng_drng_alloc = lrng_cc20_drng_alloc,
+ .lrng_drng_dealloc = lrng_cc20_drng_dealloc,
+ .lrng_drng_seed_helper = lrng_cc20_drng_seed_helper,
+ .lrng_drng_generate_helper = lrng_cc20_drng_generate_helper,
+ .lrng_hash_alloc = lrng_cc20_hash_alloc,
+ .lrng_hash_dealloc = lrng_cc20_hash_dealloc,
+ .lrng_hash_digestsize = lrng_cc20_hash_digestsize,
+ .lrng_hash_buffer = lrng_cc20_hash_buffer,
+};
diff --git a/drivers/char/lrng/lrng_chacha20.h b/drivers/char/lrng/lrng_chacha20.h
new file mode 100644
index 000000000000..1533b2490964
--- /dev/null
+++ b/drivers/char/lrng/lrng_chacha20.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * LRNG ChaCha20 definitions
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#include <crypto/chacha.h>
+
+/* State according to RFC 7539 section 2.3 */
+struct chacha20_block {
+ u32 constants[4];
+ union {
+#define CHACHA_KEY_SIZE_WORDS (CHACHA_KEY_SIZE / sizeof(u32))
+ u32 u[CHACHA_KEY_SIZE_WORDS];
+ u8 b[CHACHA_KEY_SIZE];
+ } key __latent_entropy;
+ u32 counter;
+ u32 nonce[3] __latent_entropy;
+};
+
+static inline void lrng_cc20_init_rfc7539(struct chacha20_block *chacha20)
+{
+ /* String "expand 32-byte k" */
+ chacha20->constants[0] = 0x61707865;
+ chacha20->constants[1] = 0x3320646e;
+ chacha20->constants[2] = 0x79622d32;
+ chacha20->constants[3] = 0x6b206574;
+}
diff --git a/drivers/char/lrng/lrng_drng.c b/drivers/char/lrng/lrng_drng.c
new file mode 100644
index 000000000000..ac6e40794cfe
--- /dev/null
+++ b/drivers/char/lrng/lrng_drng.c
@@ -0,0 +1,409 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG DRNG processing
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/lrng.h>
+
+#include "lrng_internal.h"
+
+/*
+ * Maximum number of seconds between DRNG reseed intervals of the DRNG. Note,
+ * this is enforced with the next request of random numbers from the
+ * DRNG. Setting this value to zero implies a reseeding attempt before every
+ * generated random number.
+ */
+int lrng_drng_reseed_max_time = 600;
+
+static atomic_t lrng_avail = ATOMIC_INIT(0);
+
+DEFINE_MUTEX(lrng_crypto_cb_update);
+
+/* DRNG for /dev/urandom, getrandom(2), get_random_bytes */
+static struct lrng_drng lrng_drng_init = {
+ .drng = &chacha20,
+ .crypto_cb = &lrng_cc20_crypto_cb,
+ .lock = __MUTEX_INITIALIZER(lrng_drng_init.lock),
+ .spin_lock = __SPIN_LOCK_UNLOCKED(lrng_drng_init.spin_lock)
+};
+
+/*
+ * DRNG for get_random_bytes when called in atomic context. This
+ * DRNG will always use the ChaCha20 DRNG. It will never benefit from a
+ * DRNG switch like the "regular" DRNG. If there was no DRNG switch, the atomic
+ * DRNG is identical to the "regular" DRNG.
+ *
+ * The reason for having this is due to the fact that DRNGs other than
+ * the ChaCha20 DRNG may sleep.
+ */
+static struct lrng_drng lrng_drng_atomic = {
+ .drng = &chacha20,
+ .crypto_cb = &lrng_cc20_crypto_cb,
+ .spin_lock = __SPIN_LOCK_UNLOCKED(lrng_drng_atomic.spin_lock)
+};
+
+/********************************** Helper ************************************/
+
+bool lrng_get_available(void)
+{
+ return likely(atomic_read(&lrng_avail));
+}
+
+void lrng_set_available(void)
+{
+ atomic_set(&lrng_avail, 1);
+}
+
+struct lrng_drng *lrng_drng_init_instance(void)
+{
+ return &lrng_drng_init;
+}
+
+struct lrng_drng *lrng_drng_atomic_instance(void)
+{
+ return &lrng_drng_atomic;
+}
+
+void lrng_drng_reset(struct lrng_drng *drng)
+{
+ atomic_set(&drng->requests, LRNG_DRNG_RESEED_THRESH);
+ drng->last_seeded = jiffies;
+ drng->fully_seeded = false;
+ drng->force_reseed = true;
+ pr_debug("reset DRNG\n");
+}
+
+/* Initialize the default DRNG during boot */
+static void lrng_drngs_init_cc20(void)
+{
+ unsigned long flags = 0;
+
+ if (lrng_get_available())
+ return;
+
+ lrng_drng_lock(&lrng_drng_init, &flags);
+ if (lrng_get_available()) {
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+ return;
+ }
+
+ lrng_drng_reset(&lrng_drng_init);
+ lrng_cc20_init_state(&chacha20);
+ lrng_state_init_seed_work();
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+
+ lrng_drng_lock(&lrng_drng_atomic, &flags);
+ lrng_drng_reset(&lrng_drng_atomic);
+ /*
+ * We do not initialize the state of the atomic DRNG as it is identical
+ * to the DRNG at this point.
+ */
+ lrng_drng_unlock(&lrng_drng_atomic, &flags);
+
+ lrng_set_available();
+}
+
+/************************* Random Number Generation ***************************/
+
+/* Inject a data buffer into the DRNG */
+static void lrng_drng_inject(struct lrng_drng *drng,
+ const u8 *inbuf, u32 inbuflen)
+{
+ const char *drng_type = unlikely(drng == &lrng_drng_atomic) ?
+ "atomic" : "regular";
+ unsigned long flags = 0;
+
+ BUILD_BUG_ON(LRNG_DRNG_RESEED_THRESH > INT_MAX);
+ pr_debug("seeding %s DRNG with %u bytes\n", drng_type, inbuflen);
+ lrng_drng_lock(drng, &flags);
+ if (drng->crypto_cb->lrng_drng_seed_helper(drng->drng,
+ inbuf, inbuflen) < 0) {
+ pr_warn("seeding of %s DRNG failed\n", drng_type);
+ atomic_set(&drng->requests, 1);
+ } else {
+ pr_debug("%s DRNG stats since last seeding: %lu secs; generate calls: %d\n",
+ drng_type,
+ (time_after(jiffies, drng->last_seeded) ?
+ (jiffies - drng->last_seeded) : 0) / HZ,
+ (LRNG_DRNG_RESEED_THRESH -
+ atomic_read(&drng->requests)));
+ drng->last_seeded = jiffies;
+ atomic_set(&drng->requests, LRNG_DRNG_RESEED_THRESH);
+ drng->force_reseed = false;
+
+ if (drng->drng == lrng_drng_atomic.drng) {
+ lrng_drng_atomic.last_seeded = jiffies;
+ atomic_set(&lrng_drng_atomic.requests,
+ LRNG_DRNG_RESEED_THRESH);
+ lrng_drng_atomic.force_reseed = false;
+ }
+ }
+ lrng_drng_unlock(drng, &flags);
+}
+
+/*
+ * Perform the seeding of the DRNG with data from noise source
+ */
+static inline int _lrng_drng_seed(struct lrng_drng *drng)
+{
+ struct entropy_buf seedbuf __aligned(LRNG_KCAPI_ALIGN);
+ unsigned long flags = 0;
+ u32 total_entropy_bits;
+ int ret;
+
+ lrng_drng_lock(drng, &flags);
+ total_entropy_bits = lrng_fill_seed_buffer(drng->crypto_cb, drng->hash,
+ &seedbuf, 0);
+ lrng_drng_unlock(drng, &flags);
+
+ /* Allow the seeding operation to be called again */
+ lrng_pool_unlock();
+ lrng_init_ops(total_entropy_bits);
+ ret = total_entropy_bits >> 3;
+
+ lrng_drng_inject(drng, (u8 *)&seedbuf, sizeof(seedbuf));
+ memzero_explicit(&seedbuf, sizeof(seedbuf));
+
+ return ret;
+}
+
+static int lrng_drng_get(struct lrng_drng *drng, u8 *outbuf, u32 outbuflen);
+static void lrng_drng_seed(struct lrng_drng *drng)
+{
+ int ret = _lrng_drng_seed(drng);
+
+ if (ret >= LRNG_DRNG_SECURITY_STRENGTH_BYTES)
+ drng->fully_seeded = true;
+
+ BUILD_BUG_ON(LRNG_MIN_SEED_ENTROPY_BITS >
+ LRNG_DRNG_SECURITY_STRENGTH_BITS);
+
+ /*
+ * Reseed atomic DRNG from current DRNG,
+ *
+ * We can obtain random numbers from DRNG as the lock type
+ * chosen by lrng_drng_get is usable with the current caller.
+ */
+ if ((drng->drng != lrng_drng_atomic.drng) &&
+ (lrng_drng_atomic.force_reseed ||
+ atomic_read(&lrng_drng_atomic.requests) <= 0 ||
+ time_after(jiffies, lrng_drng_atomic.last_seeded +
+ lrng_drng_reseed_max_time * HZ))) {
+ u8 seedbuf[LRNG_DRNG_SECURITY_STRENGTH_BYTES]
+ __aligned(LRNG_KCAPI_ALIGN);
+
+ ret = lrng_drng_get(drng, seedbuf, sizeof(seedbuf));
+
+ if (ret < 0) {
+ pr_warn("Error generating random numbers for atomic DRNG: %d\n",
+ ret);
+ } else {
+ lrng_drng_inject(&lrng_drng_atomic, seedbuf, ret);
+ }
+ memzero_explicit(&seedbuf, sizeof(seedbuf));
+ }
+}
+
+static inline void _lrng_drng_seed_work(struct lrng_drng *drng, u32 node)
+{
+ pr_debug("reseed triggered by interrupt noise source for DRNG on NUMA node %d\n",
+ node);
+ lrng_drng_seed(drng);
+ if (drng->fully_seeded) {
+ /* Prevent reseed storm */
+ drng->last_seeded += node * 100 * HZ;
+ /* Prevent draining of pool on idle systems */
+ lrng_drng_reseed_max_time += 100;
+ }
+}
+
+/*
+ * DRNG reseed trigger: Kernel thread handler triggered by the schedule_work()
+ */
+void lrng_drng_seed_work(struct work_struct *dummy)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ u32 node;
+
+ if (lrng_drng) {
+ for_each_online_node(node) {
+ struct lrng_drng *drng = lrng_drng[node];
+
+ if (drng && !drng->fully_seeded) {
+ _lrng_drng_seed_work(drng, node);
+ goto out;
+ }
+ }
+ lrng_pool_all_numa_nodes_seeded();
+ } else {
+ if (!lrng_drng_init.fully_seeded)
+ _lrng_drng_seed_work(&lrng_drng_init, 0);
+ }
+
+out:
+ /* Allow the seeding operation to be called again */
+ lrng_pool_unlock();
+}
+
+/* Force all DRNGs to reseed before next generation */
+void lrng_drng_force_reseed(void)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ u32 node;
+
+ if (!lrng_drng) {
+ lrng_drng_init.force_reseed = true;
+ pr_debug("force reseed of initial DRNG\n");
+ return;
+ }
+ for_each_online_node(node) {
+ struct lrng_drng *drng = lrng_drng[node];
+
+ if (!drng)
+ continue;
+
+ drng->force_reseed = true;
+ pr_debug("force reseed of DRNG on node %u\n", node);
+ }
+ lrng_drng_atomic.force_reseed = true;
+}
+
+/**
+ * lrng_drng_get() - Get random data out of the DRNG which is reseeded
+ * frequently.
+ *
+ * @outbuf: buffer for storing random data
+ * @outbuflen: length of outbuf
+ *
+ * Return:
+ * * < 0 in error case (DRNG generation or update failed)
+ * * >=0 returning the returned number of bytes
+ */
+static int lrng_drng_get(struct lrng_drng *drng, u8 *outbuf, u32 outbuflen)
+{
+ unsigned long flags = 0;
+ u32 processed = 0;
+
+ if (!outbuf || !outbuflen)
+ return 0;
+
+ outbuflen = min_t(size_t, outbuflen, INT_MAX);
+
+ lrng_drngs_init_cc20();
+
+ while (outbuflen) {
+ u32 todo = min_t(u32, outbuflen, LRNG_DRNG_MAX_REQSIZE);
+ int ret;
+
+ /* All but the atomic DRNG are seeded during generation */
+ if (atomic_dec_and_test(&drng->requests) ||
+ drng->force_reseed ||
+ time_after(jiffies, drng->last_seeded +
+ lrng_drng_reseed_max_time * HZ)) {
+ if (likely(drng != &lrng_drng_atomic)) {
+ if (lrng_pool_trylock())
+ atomic_set(&drng->requests, 1);
+ else
+ lrng_drng_seed(drng);
+ }
+ }
+
+ lrng_drng_lock(drng, &flags);
+ ret = drng->crypto_cb->lrng_drng_generate_helper(
+ drng->drng, outbuf + processed, todo);
+ lrng_drng_unlock(drng, &flags);
+ if (ret <= 0) {
+ pr_warn("getting random data from DRNG failed (%d)\n",
+ ret);
+ return -EFAULT;
+ }
+ processed += ret;
+ outbuflen -= ret;
+ }
+
+ return processed;
+}
+
+int lrng_drng_get_atomic(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_drng_get(&lrng_drng_atomic, outbuf, outbuflen);
+}
+
+int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ struct lrng_drng *drng = &lrng_drng_init;
+ int node = numa_node_id();
+
+ might_sleep();
+
+ if (lrng_drng && lrng_drng[node] && lrng_drng[node]->fully_seeded)
+ drng = lrng_drng[node];
+
+ return lrng_drng_get(drng, outbuf, outbuflen);
+}
+
+/* Reset LRNG such that all existing entropy is gone */
+static void _lrng_reset(struct work_struct *work)
+{
+ struct lrng_drng **lrng_drng = lrng_drng_instances();
+ unsigned long flags = 0;
+
+ if (!lrng_drng) {
+ lrng_drng_lock(&lrng_drng_init, &flags);
+ lrng_drng_reset(&lrng_drng_init);
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+ } else {
+ u32 node;
+
+ for_each_online_node(node) {
+ struct lrng_drng *drng = lrng_drng[node];
+
+ if (!drng)
+ continue;
+ lrng_drng_lock(drng, &flags);
+ lrng_drng_reset(drng);
+ lrng_drng_unlock(drng, &flags);
+ }
+ }
+ lrng_set_entropy_thresh(LRNG_INIT_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS);
+
+ lrng_reset_state();
+}
+
+static DECLARE_WORK(lrng_reset_work, _lrng_reset);
+
+void lrng_reset(void)
+{
+ schedule_work(&lrng_reset_work);
+}
+
+/***************************** Initialize LRNG *******************************/
+
+void __init lrng_drng_init_early(void)
+{
+ unsigned long flags = 0;
+
+ lrng_drng_lock(&lrng_drng_init, &flags);
+ lrng_cc20_init_state_boot(&chacha20);
+ lrng_drng_unlock(&lrng_drng_init, &flags);
+}
+
+static int __init lrng_init(void)
+{
+ lrng_drngs_init_cc20();
+
+ lrng_drngs_numa_alloc();
+ return 0;
+}
+
+late_initcall(lrng_init);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Stephan Mueller <[email protected]>");
+MODULE_DESCRIPTION("Linux Random Number Generator");
diff --git a/drivers/char/lrng/lrng_interfaces.c b/drivers/char/lrng/lrng_interfaces.c
new file mode 100644
index 000000000000..ff8b73e4c936
--- /dev/null
+++ b/drivers/char/lrng/lrng_interfaces.c
@@ -0,0 +1,652 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG User and kernel space interfaces
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/freezer.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/hw_random.h>
+#include <linux/kthread.h>
+#include <linux/poll.h>
+#include <linux/preempt.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/timex.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/random.h>
+
+#include "lrng_internal.h"
+
+/*
+ * If the entropy count falls under this number of bits, then we
+ * should wake up processes which are selecting or polling on write
+ * access to /dev/random.
+ */
+u32 lrng_write_wakeup_bits = LRNG_WRITE_WAKEUP_ENTROPY;
+
+static LIST_HEAD(lrng_ready_list);
+static DEFINE_SPINLOCK(lrng_ready_list_lock);
+
+static DECLARE_WAIT_QUEUE_HEAD(lrng_write_wait);
+static DECLARE_WAIT_QUEUE_HEAD(lrng_init_wait);
+static struct fasync_struct *fasync;
+
+struct ctl_table random_table[];
+/********************************** Helper ***********************************/
+
+/* Is the DRNG seed level too low? */
+static inline bool lrng_need_entropy(void)
+{
+ return (lrng_avail_entropy() < lrng_write_wakeup_bits);
+}
+
+void lrng_writer_wakeup(void)
+{
+ if (lrng_need_entropy() && wq_has_sleeper(&lrng_write_wait)) {
+ wake_up_interruptible(&lrng_write_wait);
+ kill_fasync(&fasync, SIGIO, POLL_OUT);
+ }
+}
+
+void lrng_init_wakeup(void)
+{
+ wake_up_all(&lrng_init_wait);
+ kill_fasync(&fasync, SIGIO, POLL_IN);
+}
+
+/**
+ * lrng_process_ready_list() - Ping all kernel internal callers waiting until
+ * the DRNG is at least minimally seeded to inform that the DRNG reached that
+ * seed level.
+ *
+ * When the SP800-90B testing is enabled, the ping only happens if the SP800-90B
+ * startup health tests are completed. This implies that kernel internal
+ * callers always have an SP800-90B compliant noise source when being
+ * pinged.
+ */
+void lrng_process_ready_list(void)
+{
+ unsigned long flags;
+ struct random_ready_callback *rdy, *tmp;
+
+ if (!lrng_sp80090b_startup_complete())
+ return;
+
+ spin_lock_irqsave(&lrng_ready_list_lock, flags);
+ list_for_each_entry_safe(rdy, tmp, &lrng_ready_list, list) {
+ struct module *owner = rdy->owner;
+
+ list_del_init(&rdy->list);
+ rdy->func(rdy);
+ module_put(owner);
+ }
+ spin_unlock_irqrestore(&lrng_ready_list_lock, flags);
+}
+
+void lrng_debug_report_seedlevel(const char *name)
+{
+#ifdef CONFIG_WARN_ALL_UNSEEDED_RANDOM
+ static void *previous = NULL;
+ void *caller = (void *) _RET_IP_;
+
+ if (READ_ONCE(previous) == caller)
+ return;
+
+ if (!lrng_state_min_seeded())
+ pr_notice("%pS %s called without reaching mimimally seeded level (available entropy %u)\n",
+ caller, name, lrng_avail_entropy());
+
+ WRITE_ONCE(previous, caller);
+#endif
+}
+
+/************************ LRNG kernel input interfaces ************************/
+
+/**
+ * add_hwgenerator_randomness() - Interface for in-kernel drivers of true
+ * hardware RNGs.
+ *
+ * Those devices may produce endless random bits and will be throttled
+ * when our pool is full.
+ *
+ * @buffer: buffer holding the entropic data from HW noise sources to be used to
+ * insert into entropy pool.
+ * @count: length of buffer
+ * @entropy_bits: amount of entropy in buffer (value is in bits)
+ */
+void add_hwgenerator_randomness(const char *buffer, size_t count,
+ size_t entropy_bits)
+{
+ /*
+ * Suspend writing if we are fully loaded with entropy.
+ * We'll be woken up again once below lrng_write_wakeup_thresh,
+ * or when the calling thread is about to terminate.
+ */
+ wait_event_interruptible(lrng_write_wait,
+ lrng_need_entropy() ||
+ lrng_state_exseed_allow(lrng_noise_source_hw) ||
+ kthread_should_stop());
+ lrng_state_exseed_set(lrng_noise_source_hw, false);
+ lrng_pool_lfsr_nonaligned(buffer, count);
+ lrng_pool_add_entropy(entropy_bits);
+}
+EXPORT_SYMBOL_GPL(add_hwgenerator_randomness);
+
+/**
+ * add_bootloader_randomness() - Handle random seed passed by bootloader.
+ *
+ * If the seed is trustworthy, it would be regarded as hardware RNGs. Otherwise
+ * it would be regarded as device data.
+ * The decision is controlled by CONFIG_RANDOM_TRUST_BOOTLOADER.
+ *
+ * @buf: buffer holding the entropic data from HW noise sources to be used to
+ * insert into entropy pool.
+ * @size: length of buffer
+ */
+void add_bootloader_randomness(const void *buf, unsigned int size)
+{
+ if (IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER))
+ add_hwgenerator_randomness(buf, size, size * 8);
+ else
+ add_device_randomness(buf, size);
+}
+EXPORT_SYMBOL_GPL(add_bootloader_randomness);
+
+/*
+ * Callback for HID layer -- use the HID event values to stir the entropy pool
+ */
+void add_input_randomness(unsigned int type, unsigned int code,
+ unsigned int value)
+{
+ static unsigned char last_value;
+
+ /* ignore autorepeat and the like */
+ if (value == last_value)
+ return;
+
+ last_value = value;
+
+ lrng_pool_lfsr_u32((type << 4) ^ code ^ (code >> 4) ^ value);
+}
+EXPORT_SYMBOL_GPL(add_input_randomness);
+
+/**
+ * add_device_randomness() - Add device- or boot-specific data to the entropy
+ * pool to help initialize it.
+ *
+ * None of this adds any entropy; it is meant to avoid the problem of
+ * the entropy pool having similar initial state across largely
+ * identical devices.
+ *
+ * @buf: buffer holding the entropic data from HW noise sources to be used to
+ * insert into entropy pool.
+ * @size: length of buffer
+ */
+void add_device_randomness(const void *buf, unsigned int size)
+{
+ lrng_pool_lfsr_nonaligned((u8 *)buf, size);
+ lrng_pool_lfsr_u32(random_get_entropy());
+ lrng_pool_lfsr_u32(jiffies);
+}
+EXPORT_SYMBOL(add_device_randomness);
+
+#ifdef CONFIG_BLOCK
+void rand_initialize_disk(struct gendisk *disk) { }
+void add_disk_randomness(struct gendisk *disk) { }
+EXPORT_SYMBOL(add_disk_randomness);
+#endif
+
+/**
+ * del_random_ready_callback() - Delete a previously registered readiness
+ * callback function.
+ *
+ * @rdy: callback definition that was registered initially
+ */
+void del_random_ready_callback(struct random_ready_callback *rdy)
+{
+ unsigned long flags;
+ struct module *owner = NULL;
+
+ spin_lock_irqsave(&lrng_ready_list_lock, flags);
+ if (!list_empty(&rdy->list)) {
+ list_del_init(&rdy->list);
+ owner = rdy->owner;
+ }
+ spin_unlock_irqrestore(&lrng_ready_list_lock, flags);
+
+ module_put(owner);
+}
+EXPORT_SYMBOL(del_random_ready_callback);
+
+/**
+ * add_random_ready_callback() - Add a callback function that will be invoked
+ * when the DRNG is mimimally seeded.
+ *
+ * @rdy: callback definition to be invoked when the LRNG is seeded
+ *
+ * Return:
+ * * 0 if callback is successfully added
+ * * -EALREADY if pool is already initialised (callback not called)
+ * * -ENOENT if module for callback is not alive
+ */
+int add_random_ready_callback(struct random_ready_callback *rdy)
+{
+ struct module *owner;
+ unsigned long flags;
+ int err = -EALREADY;
+
+ if (likely(lrng_state_min_seeded()))
+ return err;
+
+ owner = rdy->owner;
+ if (!try_module_get(owner))
+ return -ENOENT;
+
+ spin_lock_irqsave(&lrng_ready_list_lock, flags);
+ if (lrng_state_min_seeded())
+ goto out;
+
+ owner = NULL;
+
+ list_add(&rdy->list, &lrng_ready_list);
+ err = 0;
+
+out:
+ spin_unlock_irqrestore(&lrng_ready_list_lock, flags);
+
+ module_put(owner);
+
+ return err;
+}
+EXPORT_SYMBOL(add_random_ready_callback);
+
+/*********************** LRNG kernel output interfaces ************************/
+
+/**
+ * get_random_bytes() - Provider of cryptographic strong random numbers for
+ * kernel-internal usage.
+ *
+ * This function is appropriate for all in-kernel use cases. However,
+ * it will always use the ChaCha20 DRNG.
+ *
+ * @buf: buffer to store the random bytes
+ * @nbytes: size of the buffer
+ */
+void get_random_bytes(void *buf, int nbytes)
+{
+ lrng_drng_get_atomic((u8 *)buf, (u32)nbytes);
+ lrng_debug_report_seedlevel("get_random_bytes");
+}
+EXPORT_SYMBOL(get_random_bytes);
+
+/**
+ * get_random_bytes_full() - Provider of cryptographic strong random numbers
+ * for kernel-internal usage.
+ *
+ * This function is appropriate only for non-atomic use cases as this
+ * function may sleep. Though, it provides access to the full functionality
+ * of LRNG including the switchable DRNG support, that may support other
+ * DRNGs such as the SP800-90A DRBG.
+ *
+ * @buf: buffer to store the random bytes
+ * @nbytes: size of the buffer
+ */
+void get_random_bytes_full(void *buf, int nbytes)
+{
+ lrng_drng_get_sleep((u8 *)buf, (u32)nbytes);
+ lrng_debug_report_seedlevel("get_random_bytes_full");
+}
+EXPORT_SYMBOL(get_random_bytes_full);
+
+/**
+ * wait_for_random_bytes() - Wait for the LRNG to be seeded and thus
+ * guaranteed to supply cryptographically secure random numbers.
+ *
+ * This applies to: the /dev/urandom device, the get_random_bytes function,
+ * and the get_random_{u32,u64,int,long} family of functions. Using any of
+ * these functions without first calling this function forfeits the guarantee
+ * of security.
+ *
+ * Return:
+ * * 0 if the LRNG has been seeded.
+ * * -ERESTARTSYS if the function was interrupted by a signal.
+ */
+int wait_for_random_bytes(void)
+{
+ if (likely(lrng_state_min_seeded()))
+ return 0;
+ return wait_event_interruptible(lrng_init_wait,
+ lrng_state_min_seeded());
+}
+EXPORT_SYMBOL(wait_for_random_bytes);
+
+/**
+ * get_random_bytes_arch() - This function will use the architecture-specific
+ * hardware random number generator if it is available.
+ *
+ * The arch-specific hw RNG will almost certainly be faster than what we can
+ * do in software, but it is impossible to verify that it is implemented
+ * securely (as opposed, to, say, the AES encryption of a sequence number using
+ * a key known by the NSA). So it's useful if we need the speed, but only if
+ * we're willing to trust the hardware manufacturer not to have put in a back
+ * door.
+ *
+ * @buf: buffer allocated by caller to store the random data in
+ * @nbytes: length of outbuf
+ *
+ * Return: number of bytes filled in.
+ */
+int __must_check get_random_bytes_arch(void *buf, int nbytes)
+{
+ u8 *p = buf;
+
+ while (nbytes) {
+ unsigned long v;
+ int chunk = min_t(int, nbytes, sizeof(unsigned long));
+
+ if (!arch_get_random_long(&v))
+ break;
+
+ memcpy(p, &v, chunk);
+ p += chunk;
+ nbytes -= chunk;
+ }
+
+ if (nbytes)
+ lrng_drng_get_atomic((u8 *)p, (u32)nbytes);
+
+ return nbytes;
+}
+EXPORT_SYMBOL(get_random_bytes_arch);
+
+/*
+ * Returns whether or not the LRNG has been seeded.
+ *
+ * Returns: true if the urandom pool has been seeded.
+ * false if the urandom pool has not been seeded.
+ */
+bool rng_is_initialized(void)
+{
+ return lrng_state_operational();
+}
+EXPORT_SYMBOL(rng_is_initialized);
+
+/************************ LRNG user output interfaces *************************/
+
+static ssize_t lrng_read_common(char __user *buf, size_t nbytes)
+{
+ ssize_t ret = 0;
+ u8 tmpbuf[LRNG_DRNG_BLOCKSIZE] __aligned(LRNG_KCAPI_ALIGN);
+ u8 *tmp_large = NULL, *tmp = tmpbuf;
+ u32 tmplen = sizeof(tmpbuf);
+
+ if (nbytes == 0)
+ return 0;
+
+ /*
+ * Satisfy large read requests -- as the common case are smaller
+ * request sizes, such as 16 or 32 bytes, avoid a kmalloc overhead for
+ * those by using the stack variable of tmpbuf.
+ */
+ if (!CONFIG_BASE_SMALL && (nbytes > sizeof(tmpbuf))) {
+ tmplen = min_t(u32, nbytes, LRNG_DRNG_MAX_REQSIZE);
+ tmp_large = kmalloc(tmplen + LRNG_KCAPI_ALIGN, GFP_KERNEL);
+ if (!tmp_large)
+ tmplen = sizeof(tmpbuf);
+ else
+ tmp = PTR_ALIGN(tmp_large, LRNG_KCAPI_ALIGN);
+ }
+
+ while (nbytes) {
+ u32 todo = min_t(u32, nbytes, tmplen);
+ int rc = 0;
+
+ /* Reschedule if we received a large request. */
+ if ((tmp_large) && need_resched()) {
+ if (signal_pending(current)) {
+ if (ret == 0)
+ ret = -ERESTARTSYS;
+ break;
+ }
+ schedule();
+ }
+
+ rc = lrng_drng_get_sleep(tmp, todo);
+ if (rc <= 0) {
+ if (rc < 0)
+ ret = rc;
+ break;
+ }
+ if (copy_to_user(buf, tmp, rc)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ nbytes -= rc;
+ buf += rc;
+ ret += rc;
+ }
+
+ /* Wipe data just returned from memory */
+ if (tmp_large)
+ kzfree(tmp_large);
+ else
+ memzero_explicit(tmpbuf, sizeof(tmpbuf));
+
+ return ret;
+}
+
+static ssize_t
+lrng_read_common_block(int nonblock, char __user *buf, size_t nbytes)
+{
+ if (nbytes == 0)
+ return 0;
+
+ if (unlikely(!lrng_state_operational())) {
+ int ret;
+
+ if (nonblock)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(lrng_init_wait,
+ lrng_state_operational());
+ if (unlikely(ret))
+ return ret;
+ }
+
+ return lrng_read_common(buf, nbytes);
+}
+
+static ssize_t lrng_drng_read_block(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ return lrng_read_common_block(file->f_flags & O_NONBLOCK, buf, nbytes);
+}
+
+static __poll_t lrng_random_poll(struct file *file, poll_table *wait)
+{
+ __poll_t mask;
+
+ poll_wait(file, &lrng_init_wait, wait);
+ poll_wait(file, &lrng_write_wait, wait);
+ mask = 0;
+ if (lrng_state_operational())
+ mask |= EPOLLIN | EPOLLRDNORM;
+ if (lrng_need_entropy() ||
+ lrng_state_exseed_allow(lrng_noise_source_user))
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ return mask;
+}
+
+static ssize_t lrng_drng_write_common(const char __user *buffer, size_t count,
+ u32 entropy_bits)
+{
+ ssize_t ret = 0;
+ u8 buf[64] __aligned(LRNG_KCAPI_ALIGN);
+ const char __user *p = buffer;
+ u32 orig_entropy_bits = entropy_bits;
+
+ if (!lrng_get_available())
+ return -EAGAIN;
+
+ count = min_t(size_t, count, INT_MAX);
+ while (count > 0) {
+ size_t bytes = min_t(size_t, count, sizeof(buf));
+ u32 ent = min_t(u32, bytes<<3, entropy_bits);
+
+ if (copy_from_user(&buf, p, bytes))
+ return -EFAULT;
+ /* Inject data into entropy pool */
+ lrng_pool_lfsr(buf, bytes);
+ lrng_pool_add_entropy(ent);
+
+ count -= bytes;
+ p += bytes;
+ ret += bytes;
+ entropy_bits -= ent;
+
+ cond_resched();
+ }
+
+ /* Force reseed of DRNG during next data request. */
+ if (!orig_entropy_bits)
+ lrng_drng_force_reseed();
+
+ return ret;
+}
+
+static ssize_t lrng_drng_read(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos)
+{
+ if (!lrng_state_min_seeded())
+ pr_notice_ratelimited("%s - use of insufficiently seeded DRNG (%zu bytes read)\n",
+ current->comm, nbytes);
+ else if (!lrng_state_operational())
+ pr_debug_ratelimited("%s - use of not fully seeded DRNG (%zu bytes read)\n",
+ current->comm, nbytes);
+
+ return lrng_read_common(buf, nbytes);
+}
+
+static ssize_t lrng_drng_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ return lrng_drng_write_common(buffer, count, 0);
+}
+
+static long lrng_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+ int size, ent_count_bits;
+ int __user *p = (int __user *)arg;
+
+ switch (cmd) {
+ case RNDGETENTCNT:
+ ent_count_bits = lrng_avail_entropy();
+ if (put_user(ent_count_bits, p))
+ return -EFAULT;
+ return 0;
+ case RNDADDTOENTCNT:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ if (get_user(ent_count_bits, p))
+ return -EFAULT;
+ ent_count_bits = (int)lrng_avail_entropy() + ent_count_bits;
+ if (ent_count_bits < 0)
+ ent_count_bits = 0;
+ if (ent_count_bits > LRNG_POOL_SIZE_BITS)
+ ent_count_bits = LRNG_POOL_SIZE_BITS;
+ lrng_pool_set_entropy(ent_count_bits);
+ return 0;
+ case RNDADDENTROPY:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ if (get_user(ent_count_bits, p++))
+ return -EFAULT;
+ if (ent_count_bits < 0)
+ return -EINVAL;
+ if (get_user(size, p++))
+ return -EFAULT;
+ if (size < 0)
+ return -EINVAL;
+ lrng_state_exseed_set(lrng_noise_source_user, false);
+ /* there cannot be more entropy than data */
+ ent_count_bits = min(ent_count_bits, size<<3);
+ return lrng_drng_write_common((const char __user *)p, size,
+ ent_count_bits);
+ case RNDZAPENTCNT:
+ case RNDCLEARPOOL:
+ /* Clear the entropy pool counter. */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ lrng_pool_set_entropy(0);
+ return 0;
+ case RNDRESEEDCRNG:
+ /*
+ * We leave the capability check here since it is present
+ * in the upstream's RNG implementation. Yet, user space
+ * can trigger a reseed as easy as writing into /dev/random
+ * or /dev/urandom where no privilege is needed.
+ */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ /* Force a reseed of all DRNGs */
+ lrng_drng_force_reseed();
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int lrng_fasync(int fd, struct file *filp, int on)
+{
+ return fasync_helper(fd, filp, on, &fasync);
+}
+
+const struct file_operations random_fops = {
+ .read = lrng_drng_read_block,
+ .write = lrng_drng_write,
+ .poll = lrng_random_poll,
+ .unlocked_ioctl = lrng_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .fasync = lrng_fasync,
+ .llseek = noop_llseek,
+};
+
+const struct file_operations urandom_fops = {
+ .read = lrng_drng_read,
+ .write = lrng_drng_write,
+ .unlocked_ioctl = lrng_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .fasync = lrng_fasync,
+ .llseek = noop_llseek,
+};
+
+SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count,
+ unsigned int, flags)
+{
+ if (flags & ~(GRND_NONBLOCK|GRND_RANDOM|GRND_INSECURE))
+ return -EINVAL;
+
+ /*
+ * Requesting insecure and blocking randomness at the same time makes
+ * no sense.
+ */
+ if ((flags &
+ (GRND_INSECURE|GRND_RANDOM)) == (GRND_INSECURE|GRND_RANDOM))
+ return -EINVAL;
+
+ if (count > INT_MAX)
+ count = INT_MAX;
+
+ if (flags & GRND_INSECURE)
+ return lrng_drng_read(NULL, buf, count, NULL);
+
+ return lrng_read_common_block(flags & GRND_NONBLOCK, buf, count);
+}
diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h
new file mode 100644
index 000000000000..f86afe8d2612
--- /dev/null
+++ b/drivers/char/lrng/lrng_internal.h
@@ -0,0 +1,342 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * Copyright (C) 2018 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#ifndef _LRNG_INTERNAL_H
+#define _LRNG_INTERNAL_H
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+
+/*************************** General LRNG parameter ***************************/
+
+/* Entropy pool parameter
+ *
+ * The LRNG_POOL_SIZE cannot be smaller than 64 bytes as the SHA-1 operation
+ * in lrng_chacha20.c requires multiples of 64 bytes
+ */
+#define LRNG_POOL_SIZE (16 << CONFIG_LRNG_POOL_SIZE)
+#define LRNG_POOL_WORD_BYTES (4) /* (sizeof(atomic_t)) */
+#define LRNG_POOL_SIZE_BYTES (LRNG_POOL_SIZE * LRNG_POOL_WORD_BYTES)
+#define LRNG_POOL_SIZE_BITS (LRNG_POOL_SIZE_BYTES * 8)
+#define LRNG_POOL_WORD_BITS (LRNG_POOL_WORD_BYTES * 8)
+
+/* Security strength of LRNG -- this must match DRNG security strength */
+#define LRNG_DRNG_SECURITY_STRENGTH_BYTES 32
+#define LRNG_DRNG_SECURITY_STRENGTH_BITS (LRNG_DRNG_SECURITY_STRENGTH_BYTES * 8)
+#define LRNG_DRNG_BLOCKSIZE 64 /* Maximum of DRNG block sizes */
+
+/*
+ * SP800-90A defines a maximum request size of 1<<16 bytes. The given value is
+ * considered a safer margin.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_DRNG_MAX_REQSIZE (1<<12)
+
+/*
+ * SP800-90A defines a maximum number of requests between reseeds of 2^48.
+ * The given value is considered a much safer margin, balancing requests for
+ * frequent reseeds with the need to conserve entropy. This value MUST NOT be
+ * larger than INT_MAX because it is used in an atomic_t.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_DRNG_RESEED_THRESH (1<<20)
+
+/*
+ * Number of interrupts to be recorded to assume that DRNG security strength
+ * bits of entropy are received.
+ * Note: a value below the DRNG security strength should not be defined as this
+ * may imply the DRNG can never be fully seeded in case other noise
+ * sources are unavailable.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_IRQ_ENTROPY_BITS LRNG_DRNG_SECURITY_STRENGTH_BITS
+
+/*
+ * Min required seed entropy is 128 bits covering the minimum entropy
+ * requirement of SP800-131A and the German BSI's TR02102.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_FULL_SEED_ENTROPY_BITS LRNG_DRNG_SECURITY_STRENGTH_BITS
+#define LRNG_MIN_SEED_ENTROPY_BITS 128
+#define LRNG_INIT_ENTROPY_BITS 32
+
+/*
+ * Amount of entropy that is lost with the conditioning functions of LFSR and
+ * hash_df as shown with the entropy analysis compliant to SP800-90B.
+ */
+#define LRNG_CONDITIONING_ENTROPY_LOSS 1
+
+/*
+ * Wakeup value
+ *
+ * This value is allowed to be changed.
+ */
+#if (LRNG_POOL_SIZE_BITS <= (LRNG_DRNG_SECURITY_STRENGTH_BITS * 2))
+# define LRNG_WRITE_WAKEUP_ENTROPY (LRNG_DRNG_SECURITY_STRENGTH_BITS + \
+ LRNG_CONDITIONING_ENTROPY_LOSS)
+#else
+# define LRNG_WRITE_WAKEUP_ENTROPY (LRNG_DRNG_SECURITY_STRENGTH_BITS * 2)
+#endif
+
+/*
+ * Oversampling factor of IRQ events to obtain
+ * LRNG_DRNG_SECURITY_STRENGTH_BYTES. This factor is used when a
+ * high-resolution time stamp is not available. In this case, jiffies and
+ * register contents are used to fill the entropy pool. These noise sources
+ * are much less entropic than the high-resolution timer. The entropy content
+ * is the entropy content assumed with LRNG_IRQ_ENTROPY_BITS divided by
+ * LRNG_IRQ_OVERSAMPLING_FACTOR.
+ *
+ * This value is allowed to be changed.
+ */
+#define LRNG_IRQ_OVERSAMPLING_FACTOR 10
+
+/*
+ * Alignmask which should cover all cipher implementations
+ * WARNING: If this is changed to a value larger than 8, manual
+ * alignment is necessary as older versions of GCC may not be capable
+ * of aligning stack variables at boundaries greater than 8.
+ * In this case, PTR_ALIGN must be used.
+ */
+#define LRNG_KCAPI_ALIGN 8
+
+/************************ Default DRNG implementation *************************/
+
+extern struct chacha20_state chacha20;
+extern const struct lrng_crypto_cb lrng_cc20_crypto_cb;
+void lrng_cc20_init_state(struct chacha20_state *state);
+void lrng_cc20_init_state_boot(struct chacha20_state *state);
+
+/********************************** /proc *************************************/
+
+static inline void lrng_pool_inc_numa_node(void) { }
+
+/****************************** LRNG interfaces *******************************/
+
+extern u32 lrng_write_wakeup_bits;
+extern int lrng_drng_reseed_max_time;
+
+void lrng_writer_wakeup(void);
+void lrng_init_wakeup(void);
+void lrng_debug_report_seedlevel(const char *name);
+void lrng_process_ready_list(void);
+
+/* External interface to use of the switchable DRBG inside the kernel */
+void get_random_bytes_full(void *buf, int nbytes);
+
+/************************** Entropy pool management ***************************/
+
+enum lrng_external_noise_source {
+ lrng_noise_source_hw,
+ lrng_noise_source_user
+};
+
+bool lrng_state_exseed_allow(enum lrng_external_noise_source source);
+void lrng_state_exseed_set(enum lrng_external_noise_source source, bool type);
+void lrng_state_init_seed_work(void);
+u32 lrng_avail_entropy(void);
+void lrng_set_entropy_thresh(u32 new);
+int lrng_pool_trylock(void);
+void lrng_pool_unlock(void);
+void lrng_reset_state(void);
+void lrng_pool_all_numa_nodes_seeded(void);
+bool lrng_state_min_seeded(void);
+bool lrng_state_fully_seeded(void);
+bool lrng_state_operational(void);
+bool lrng_pool_highres_timer(void);
+void lrng_pool_set_entropy(u32 entropy_bits);
+void lrng_pool_lfsr(const u8 *buf, u32 buflen);
+void lrng_pool_lfsr_nonaligned(const u8 *buf, u32 buflen);
+void lrng_pool_lfsr_u32(u32 value);
+void lrng_pool_add_irq(u32 irq_num);
+void lrng_pool_add_entropy(u32 entropy_bits);
+
+struct entropy_buf {
+ u8 a[LRNG_DRNG_SECURITY_STRENGTH_BYTES];
+ u8 b[LRNG_DRNG_SECURITY_STRENGTH_BYTES];
+ u8 c[LRNG_DRNG_SECURITY_STRENGTH_BYTES];
+ u32 now;
+};
+
+int lrng_fill_seed_buffer(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct entropy_buf *entropy_buf, u32 entropy_retain);
+void lrng_init_ops(u32 seed_bits);
+
+/************************** Jitter RNG Noise Source ***************************/
+
+#ifdef CONFIG_LRNG_JENT
+u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen);
+u32 lrng_jent_entropylevel(void);
+#else /* CONFIG_CRYPTO_JITTERENTROPY */
+static inline u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen) {return 0; }
+static inline u32 lrng_jent_entropylevel(void) { return 0; }
+#endif /* CONFIG_CRYPTO_JITTERENTROPY */
+
+/*************************** CPU-based Noise Source ***************************/
+
+u32 lrng_get_arch(u8 *outbuf);
+u32 lrng_slow_noise_req_entropy(u32 required_entropy_bits);
+
+/****************************** DRNG processing *******************************/
+
+/* Secondary DRNG state handle */
+struct lrng_drng {
+ void *drng; /* DRNG handle */
+ void *hash; /* Hash handle */
+ const struct lrng_crypto_cb *crypto_cb; /* Crypto callbacks */
+ atomic_t requests; /* Number of DRNG requests */
+ unsigned long last_seeded; /* Last time it was seeded */
+ bool fully_seeded; /* Is DRNG fully seeded? */
+ bool force_reseed; /* Force a reseed */
+ struct mutex lock;
+ spinlock_t spin_lock;
+};
+
+extern struct mutex lrng_crypto_cb_update;
+
+struct lrng_drng *lrng_drng_init_instance(void);
+struct lrng_drng *lrng_drng_atomic_instance(void);
+
+static __always_inline bool lrng_drng_is_atomic(struct lrng_drng *drng)
+{
+ return (drng->drng == lrng_drng_atomic_instance()->drng);
+}
+
+/* Lock the DRNG */
+static __always_inline void lrng_drng_lock(struct lrng_drng *drng,
+ unsigned long *flags)
+ __acquires(&drng->spin_lock)
+{
+ /* Use spin lock in case the atomic DRNG context is used */
+ if (lrng_drng_is_atomic(drng)) {
+ spin_lock_irqsave(&drng->spin_lock, *flags);
+
+ /*
+ * In case a lock transition happened while we were spinning,
+ * catch this case and use the new lock type.
+ */
+ if (!lrng_drng_is_atomic(drng)) {
+ spin_unlock_irqrestore(&drng->spin_lock, *flags);
+ __acquire(&drng->spin_lock);
+ mutex_lock(&drng->lock);
+ }
+ } else {
+ __acquire(&drng->spin_lock);
+ mutex_lock(&drng->lock);
+ }
+}
+
+/* Unlock the DRNG */
+static __always_inline void lrng_drng_unlock(struct lrng_drng *drng,
+ unsigned long *flags)
+ __releases(&drng->spin_lock)
+{
+ if (lrng_drng_is_atomic(drng)) {
+ spin_unlock_irqrestore(&drng->spin_lock, *flags);
+ } else {
+ mutex_unlock(&drng->lock);
+ __release(&drng->spin_lock);
+ }
+}
+
+void lrng_drng_init_early(void);
+bool lrng_get_available(void);
+void lrng_set_available(void);
+void lrng_drng_reset(struct lrng_drng *drng);
+int lrng_drng_get_atomic(u8 *outbuf, u32 outbuflen);
+int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen);
+void lrng_drng_force_reseed(void);
+void lrng_drng_seed_work(struct work_struct *dummy);
+
+static inline struct lrng_drng **lrng_drng_instances(void) { return NULL; }
+static inline void lrng_drngs_numa_alloc(void) { return; }
+
+/************************** Health Test linking code **************************/
+
+enum lrng_health_res {
+ lrng_health_pass, /* Health test passes on time stamp */
+ lrng_health_fail_use, /* Time stamp unhealthy, but mix in */
+ lrng_health_fail_drop /* Time stamp unhealthy, drop it */
+};
+
+#ifdef CONFIG_LRNG_HEALTH_TESTS
+bool lrng_sp80090b_startup_complete(void);
+bool lrng_sp80090b_compliant(void);
+
+enum lrng_health_res lrng_health_test(u32 now_time);
+void lrng_health_disable(void);
+
+void lrng_reset(void);
+#else /* CONFIG_LRNG_HEALTH_TESTS */
+static inline bool lrng_sp80090b_startup_complete(void) { return true; }
+static inline bool lrng_sp80090b_compliant(void) { return false; }
+
+static inline enum lrng_health_res
+lrng_health_test(u32 now_time) { return lrng_health_pass; }
+static inline void lrng_health_disable(void) { }
+#endif /* CONFIG_LRNG_HEALTH_TESTS */
+
+/****************************** Helper code ***********************************/
+
+static inline u32 atomic_read_u32(atomic_t *v)
+{
+ return (u32)atomic_read(v);
+}
+
+/*************************** Auxiliary functions ******************************/
+
+void invalidate_batched_entropy(void);
+
+/***************************** Testing code ***********************************/
+
+#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY
+bool lrng_raw_hires_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_HIRES_ENTROPY */
+static inline bool lrng_raw_hires_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_HIRES_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY
+bool lrng_raw_jiffies_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */
+static inline bool lrng_raw_jiffies_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY
+bool lrng_raw_irq_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_IRQ_ENTROPY */
+static inline bool lrng_raw_irq_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_IRQ_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY
+bool lrng_raw_irqflags_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */
+static inline bool lrng_raw_irqflags_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY
+bool lrng_raw_retip_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_RETIP_ENTROPY */
+static inline bool lrng_raw_retip_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_RETIP_ENTROPY */
+
+#ifdef CONFIG_LRNG_RAW_ARRAY
+bool lrng_raw_array_entropy_store(u32 value);
+#else /* CONFIG_LRNG_RAW_ARRAY */
+static inline bool lrng_raw_array_entropy_store(u32 value) { return false; }
+#endif /* CONFIG_LRNG_RAW_ARRAY */
+
+#ifdef CONFIG_LRNG_IRQ_PERF
+bool lrng_perf_time(u32 start);
+#else /* CONFIG_LRNG_IRQ_PERF */
+static inline bool lrng_perf_time(u32 start) { return false; }
+#endif /*CONFIG_LRNG_IRQ_PERF */
+
+#endif /* _LRNG_INTERNAL_H */
diff --git a/drivers/char/lrng/lrng_lfsr.h b/drivers/char/lrng/lrng_lfsr.h
new file mode 100644
index 000000000000..978ba97107e4
--- /dev/null
+++ b/drivers/char/lrng/lrng_lfsr.h
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * LRNG Linear Feedback Shift Register
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+/* Status information about IRQ noise source */
+struct lrng_irq_info {
+ atomic_t num_events; /* Number of healthy IRQs since last read */
+ atomic_t num_events_thresh; /* Reseed threshold */
+ atomic_t reseed_in_progress; /* Flag for on executing reseed */
+ bool irq_highres_timer; /* Is high-resolution timer available? */
+ u32 irq_entropy_bits; /* LRNG_IRQ_ENTROPY_BITS? */
+};
+
+/*
+ * This is the entropy pool used by the slow noise source. Its size should
+ * be at least as large as LRNG_DRNG_SECURITY_STRENGTH_BITS.
+ *
+ * The pool array is aligned to 8 bytes to comfort the kernel crypto API cipher
+ * implementations of the hash functions used to read the pool: for some
+ * accelerated implementations, we need an alignment to avoid a realignment
+ * which involves memcpy(). The alignment to 8 bytes should satisfy all crypto
+ * implementations.
+ *
+ * LRNG_POOL_SIZE is allowed to be changed only if the taps of the polynomial
+ * used for the LFSR are changed as well. The size must be in powers of 2 due
+ * to the mask handling in lrng_pool_lfsr_u32 which uses AND instead of modulo.
+ */
+struct lrng_pool {
+ union {
+ struct {
+ /*
+ * hash_df implementation: counter, requested_bits and
+ * pool form a linear buffer that is used in the
+ * hash_df function specified in SP800-90A section
+ * 10.3.1
+ */
+ unsigned char counter;
+ __be32 requested_bits;
+
+ /* Pool */
+ atomic_t pool[LRNG_POOL_SIZE] __latent_entropy;
+ /* Ptr into pool for next IRQ word injection */
+ atomic_t pool_ptr;
+ /* rotate for LFSR */
+ atomic_t input_rotate;
+ /* All NUMA DRNGs seeded? */
+ bool all_online_numa_node_seeded;
+ /* IRQ noise source status info */
+ struct lrng_irq_info irq_info;
+ /* Serialize read of entropy pool */
+ spinlock_t lock;
+ };
+ /*
+ * Static SHA-1 implementation in lrng_cc20_hash_buffer
+ * processes data 64-byte-wise. Hence, ensure proper size
+ * of LRNG entropy pool data structure.
+ */
+ u8 hash_input_buf[LRNG_POOL_SIZE_BYTES + 64];
+ };
+};
+
+/*
+ * Implement a (modified) twisted Generalized Feedback Shift Register. (See M.
+ * Matsumoto & Y. Kurita, 1992. Twisted GFSR generators. ACM Transactions on
+ * Modeling and Computer Simulation 2(3):179-194. Also see M. Matsumoto & Y.
+ * Kurita, 1994. Twisted GFSR generators II. ACM Transactions on Modeling and
+ * Computer Simulation 4:254-266).
+ */
+static u32 const lrng_twist_table[8] = {
+ 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
+ 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
+
+/*
+ * The polynomials for the LFSR are taken from the document "Table of Linear
+ * Feedback Shift Registers" by Roy Ward, Tim Molteno, October 26, 2007.
+ * The first polynomial is from "Primitive Binary Polynomials" by Wayne
+ * Stahnke (1973) and is primitive as well as irreducible.
+ *
+ * Note, the tap values are smaller by one compared to the documentation because
+ * they are used as an index into an array where the index starts by zero.
+ *
+ * All polynomials were also checked to be primitive and irreducible with magma
+ * which ensures that the key property of the LFSR providing a compression
+ * function for entropy is guaranteed.
+ */
+static u32 const lrng_lfsr_polynomial[][4] = {
+ { 15, 13, 12, 10 }, /* 16 words */
+ { 31, 29, 25, 24 }, /* 32 words */
+ { 63, 62, 60, 59 }, /* 64 words */
+ { 127, 28, 26, 1 }, /* 128 words by Stahnke */
+ { 255, 253, 250, 245 }, /* 256 words */
+ { 511, 509, 506, 503 }, /* 512 words */
+ { 1023, 1014, 1001, 1000 }, /* 1024 words */
+ { 2047, 2034, 2033, 2028 }, /* 2048 words */
+ { 4095, 4094, 4080, 4068 }, /* 4096 words */
+};
+
+static inline void _lrng_pool_lfsr_u32(struct lrng_pool *pool, u32 value)
+{
+ /*
+ * Process the LFSR by altering not adjacent words but rather
+ * more spaced apart words. Using a prime number ensures that all words
+ * are processed evenly. As some the LFSR polynomials taps are close
+ * together, processing adjacent words with the LSFR taps may be
+ * inappropriate as the data just mixed-in at these taps may be not
+ * independent from the current data to be mixed in.
+ */
+ u32 ptr = (u32)atomic_add_return_relaxed(67, &pool->pool_ptr) &
+ (LRNG_POOL_SIZE - 1);
+ /*
+ * Add 7 bits of rotation to the pool. At the beginning of the
+ * pool, add an extra 7 bits rotation, so that successive passes
+ * spread the input bits across the pool evenly.
+ *
+ * Note, there is a race between getting ptr and calculating
+ * input_rotate when ptr is obtained on two or more CPUs at the
+ * same time. This race is irrelevant as it may only come into effect
+ * if 3 or more CPUs race at the same time which is very unlikely. If
+ * the race happens, it applies to one event only. As this rolling
+ * supports the LFSR without being strictly needed, we accept this
+ * race.
+ */
+ u32 input_rotate = (u32)atomic_add_return_relaxed((ptr ? 7 : 14),
+ &pool->input_rotate) & 31;
+ u32 word = rol32(value, input_rotate);
+
+ BUILD_BUG_ON(LRNG_POOL_WORD_BYTES != sizeof(pool->pool[0]));
+ BUILD_BUG_ON(LRNG_POOL_SIZE - 1 !=
+ lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][0]);
+ word ^= atomic_read_u32(&pool->pool[ptr]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][0]) &
+ (LRNG_POOL_SIZE - 1)]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][1]) &
+ (LRNG_POOL_SIZE - 1)]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][2]) &
+ (LRNG_POOL_SIZE - 1)]);
+ word ^= atomic_read_u32(&pool->pool[
+ (ptr + lrng_lfsr_polynomial[CONFIG_LRNG_POOL_SIZE][3]) &
+ (LRNG_POOL_SIZE - 1)]);
+
+ word = (word >> 3) ^ lrng_twist_table[word & 7];
+ atomic_set(&pool->pool[ptr], word);
+}
+
+u32 __lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct lrng_pool *pool, u8 *outbuf, u32 requested_bits);
diff --git a/drivers/char/lrng/lrng_pool.c b/drivers/char/lrng/lrng_pool.c
new file mode 100644
index 000000000000..0d4111ce7bc2
--- /dev/null
+++ b/drivers/char/lrng/lrng_pool.c
@@ -0,0 +1,589 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Entropy pool management
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <asm/irq_regs.h>
+#include <linux/lrng.h>
+#include <linux/percpu.h>
+#include <linux/random.h>
+#include <linux/utsname.h>
+#include <linux/workqueue.h>
+
+#include "lrng_internal.h"
+#include "lrng_lfsr.h"
+
+struct lrng_state {
+ bool lrng_operational; /* Is DRNG operational? */
+ bool lrng_fully_seeded; /* Is DRNG fully seeded? */
+ bool lrng_min_seeded; /* Is DRNG minimally seeded? */
+
+ /*
+ * To ensure that external entropy providers cannot dominate the
+ * internal noise sources but yet cannot be dominated by internal
+ * noise sources, the following booleans are intended to allow
+ * external to provide seed once when a DRNG reseed occurs. This
+ * triggering of external noise source is performed even when the
+ * entropy pool has sufficient entropy.
+ */
+ bool lrng_seed_hw; /* Allow HW to provide seed */
+ bool lrng_seed_user; /* Allow user space to provide seed */
+
+ struct work_struct lrng_seed_work; /* (re)seed work queue */
+};
+
+static struct lrng_pool lrng_pool __aligned(LRNG_KCAPI_ALIGN) = {
+ .irq_info = {
+ .irq_entropy_bits = LRNG_IRQ_ENTROPY_BITS,
+ .num_events_thresh = ATOMIC_INIT(LRNG_INIT_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS),
+ /* Sample IRQ pointer data at least during boot */
+ .irq_highres_timer = false },
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_pool.lock)
+};
+
+static struct lrng_state lrng_state = { false, false, false, true, true };
+
+/********************************** Helper ***********************************/
+
+/* External entropy provider is allowed to provide seed data */
+bool lrng_state_exseed_allow(enum lrng_external_noise_source source)
+{
+ if (source == lrng_noise_source_hw)
+ return lrng_state.lrng_seed_hw;
+ return lrng_state.lrng_seed_user;
+}
+
+/* Enable / disable external entropy provider to furnish seed */
+void lrng_state_exseed_set(enum lrng_external_noise_source source, bool type)
+{
+ if (source == lrng_noise_source_hw)
+ lrng_state.lrng_seed_hw = type;
+ else
+ lrng_state.lrng_seed_user = type;
+}
+
+static inline void lrng_state_exseed_allow_all(void)
+{
+ lrng_state_exseed_set(lrng_noise_source_hw, true);
+ lrng_state_exseed_set(lrng_noise_source_user, true);
+}
+
+void lrng_state_init_seed_work(void)
+{
+ INIT_WORK(&lrng_state.lrng_seed_work, lrng_drng_seed_work);
+}
+
+static inline u32 lrng_entropy_to_data(u32 entropy_bits)
+{
+ return ((entropy_bits * lrng_pool.irq_info.irq_entropy_bits) /
+ LRNG_DRNG_SECURITY_STRENGTH_BITS);
+}
+
+static inline u32 lrng_data_to_entropy(u32 irqnum)
+{
+ return ((irqnum * LRNG_DRNG_SECURITY_STRENGTH_BITS) /
+ lrng_pool.irq_info.irq_entropy_bits);
+}
+
+u32 lrng_avail_entropy(void)
+{
+ return min_t(u32, LRNG_POOL_SIZE_BITS, lrng_data_to_entropy(
+ atomic_read_u32(&lrng_pool.irq_info.num_events)));
+}
+
+void lrng_set_entropy_thresh(u32 new)
+{
+ atomic_set(&lrng_pool.irq_info.num_events_thresh,
+ lrng_entropy_to_data(new));
+}
+
+/*
+ * Reading of the LRNG pool is only allowed by one caller. The reading is
+ * only performed to (re)seed DRNGs. Thus, if this "lock" is already taken,
+ * the reseeding operation is in progress. The caller is not intended to wait
+ * but continue with its other operation.
+ */
+int lrng_pool_trylock(void)
+{
+ return atomic_cmpxchg(&lrng_pool.irq_info.reseed_in_progress, 0, 1);
+}
+
+void lrng_pool_unlock(void)
+{
+ atomic_set(&lrng_pool.irq_info.reseed_in_progress, 0);
+}
+
+void lrng_reset_state(void)
+{
+ struct lrng_irq_info *irq_info = &lrng_pool.irq_info;
+
+ atomic_set(&irq_info->num_events, 0);
+ lrng_state.lrng_operational = false;
+ lrng_state.lrng_fully_seeded = false;
+ lrng_state.lrng_min_seeded = false;
+ lrng_pool.all_online_numa_node_seeded = false;
+ pr_debug("reset LRNG\n");
+}
+
+void lrng_pool_all_numa_nodes_seeded(void)
+{
+ lrng_pool.all_online_numa_node_seeded = true;
+}
+
+bool lrng_state_min_seeded(void)
+{
+ return lrng_state.lrng_min_seeded;
+}
+
+bool lrng_state_fully_seeded(void)
+{
+ return lrng_state.lrng_fully_seeded;
+}
+
+bool lrng_state_operational(void)
+{
+ return lrng_state.lrng_operational;
+}
+
+bool lrng_pool_highres_timer(void)
+{
+ return lrng_pool.irq_info.irq_highres_timer;
+}
+
+void lrng_pool_set_entropy(u32 entropy_bits)
+{
+ atomic_set(&lrng_pool.irq_info.num_events,
+ lrng_entropy_to_data(entropy_bits));
+}
+
+static void lrng_pool_configure(bool highres_timer, u32 irq_entropy_bits)
+{
+ struct lrng_irq_info *irq_info = &lrng_pool.irq_info;
+
+ irq_info->irq_highres_timer = highres_timer;
+ if (irq_info->irq_entropy_bits != irq_entropy_bits) {
+ irq_info->irq_entropy_bits = irq_entropy_bits;
+ /* Reset the threshold based on new oversampling factor. */
+ lrng_set_entropy_thresh(atomic_read_u32(
+ &irq_info->num_events_thresh));
+ }
+}
+
+static int __init lrng_init_time_source(void)
+{
+ if (random_get_entropy() || random_get_entropy()) {
+ /*
+ * As the highres timer is identified here, previous interrupts
+ * obtained during boot time are treated like a lowres-timer
+ * would have been present.
+ */
+ lrng_pool_configure(true, LRNG_IRQ_ENTROPY_BITS);
+ } else {
+ lrng_health_disable();
+ lrng_pool_configure(false, LRNG_IRQ_ENTROPY_BITS *
+ LRNG_IRQ_OVERSAMPLING_FACTOR);
+ pr_warn("operating without high-resolution timer and applying IRQ oversampling factor %u\n",
+ LRNG_IRQ_OVERSAMPLING_FACTOR);
+ }
+
+ return 0;
+}
+
+core_initcall(lrng_init_time_source);
+
+/* invoke function with buffer aligned to 4 bytes */
+void lrng_pool_lfsr(const u8 *buf, u32 buflen)
+{
+ u32 *p_buf = (u32 *)buf;
+
+ for (; buflen >= 4; buflen -= 4)
+ lrng_pool_lfsr_u32(*p_buf++);
+
+ buf = (u8 *)p_buf;
+ while (buflen--)
+ lrng_pool_lfsr_u32(*buf++);
+}
+
+void lrng_pool_lfsr_nonaligned(const u8 *buf, u32 buflen)
+{
+ while (buflen) {
+ if (!((unsigned long)buf & (sizeof(u32) - 1))) {
+ lrng_pool_lfsr(buf, buflen);
+ return;
+ }
+
+ lrng_pool_lfsr_u32(*buf++);
+ buflen--;
+ }
+}
+
+/**************************** Interrupt processing ****************************/
+
+/*
+ * Hot code path - inject data into entropy pool using LFSR
+ */
+void lrng_pool_lfsr_u32(u32 value)
+{
+ _lrng_pool_lfsr_u32(&lrng_pool, value);
+}
+
+/*
+ * Hot code path - mix data into entropy pool
+ */
+void lrng_pool_add_irq(u32 irq_num)
+{
+ struct lrng_irq_info *irq_info = &lrng_pool.irq_info;
+
+ atomic_add(irq_num, &irq_info->num_events);
+
+ /*
+ * Once all DRNGs are fully seeded, the interrupt noise
+ * sources will not trigger any reseeding any more.
+ */
+ if (likely(lrng_pool.all_online_numa_node_seeded))
+ return;
+
+ /* Only try to reseed if the DRNG is alive. */
+ if (!lrng_get_available())
+ return;
+
+ /* Only trigger the DRNG reseed if we have collected enough IRQs. */
+ if (atomic_read_u32(&lrng_pool.irq_info.num_events) <
+ atomic_read_u32(&lrng_pool.irq_info.num_events_thresh))
+ return;
+
+ /* Ensure that the seeding only occurs once at any given time. */
+ if (lrng_pool_trylock())
+ return;
+
+ /* Seed the DRNG with IRQ noise. */
+ schedule_work(&lrng_state.lrng_seed_work);
+}
+
+void lrng_pool_add_entropy(u32 entropy_bits)
+{
+ lrng_pool_add_irq(lrng_entropy_to_data(entropy_bits));
+}
+
+/*
+ * Generate a hashed output of pool using the SP800-90A section 10.3.1 hash_df
+ * function
+ */
+u32 __lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct lrng_pool *pool, u8 *outbuf, u32 requested_bits)
+{
+ u32 digestsize, requested_bytes = requested_bits >> 3,
+ generated_bytes = 0;
+ u8 digest[64] __aligned(LRNG_KCAPI_ALIGN);
+
+ digestsize = crypto_cb->lrng_hash_digestsize(hash);
+ if (digestsize > sizeof(digest)) {
+ pr_err("Digest buffer too small\n");
+ return 0;
+ }
+
+ pool->counter = 1;
+ pool->requested_bits = cpu_to_be32(requested_bytes << 3);
+
+ while (requested_bytes) {
+ u32 tocopy = min_t(u32, requested_bytes, digestsize);
+
+ /* The counter must not wrap */
+ if (pool->counter == 0)
+ goto out;
+
+ if (crypto_cb->lrng_hash_buffer(hash, (u8 *)pool,
+ LRNG_POOL_SIZE_BYTES + 64,
+ digest))
+ goto out;
+
+ /* Copy the data out to the caller */
+ memcpy(outbuf + generated_bytes, digest, tocopy);
+ requested_bytes -= tocopy;
+ generated_bytes += tocopy;
+ pool->counter++;
+ }
+
+out:
+ /* Mix read data back into pool for backtracking resistance */
+ if (generated_bytes)
+ lrng_pool_lfsr(outbuf, generated_bytes);
+ memzero_explicit(digest, digestsize);
+ return (generated_bytes<<3);
+}
+
+static inline u32 lrng_pool_hash_df(const struct lrng_crypto_cb *crypto_cb,
+ void *hash, u8 *outbuf, u32 requested_bits)
+{
+ return __lrng_pool_hash_df(crypto_cb, hash, &lrng_pool, outbuf,
+ requested_bits);
+}
+
+/**
+ * lrng_get_pool() - Read the entropy pool out for use.
+ *
+ * This function handles the translation from the number of received interrupts
+ * into an entropy statement. The conversion depends on LRNG_IRQ_ENTROPY_BITS
+ * which defines how many interrupts must be received to obtain 256 bits of
+ * entropy. With this value, the function lrng_data_to_entropy converts a given
+ * data size (received interrupts, requested amount of data, etc.) into an
+ * entropy statement. lrng_entropy_to_data does the reverse.
+ *
+ * Both functions are agnostic about the type of data: when the number of
+ * interrupts is processed by these functions, the resulting entropy value is in
+ * bits as we assume the entropy of interrupts is measured in bits. When data is
+ * processed, the entropy value is in bytes as the data is measured in bytes.
+ *
+ * @outbuf: buffer to store data in with size LRNG_DRNG_SECURITY_STRENGTH_BYTES
+ * @requested_entropy_bits: requested bits of entropy -- the function will
+ * return at least this amount of entropy if available
+ * @entropy_retain: amount of entropy in bits that should be left in the pool
+ *
+ * Return: estimated entropy from the IRQs that was obtained
+ */
+static u32 lrng_get_pool(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ u8 *outbuf, u32 requested_entropy_bits,
+ u32 entropy_retain)
+{
+ struct lrng_pool *pool = &lrng_pool;
+ struct lrng_state *state = &lrng_state;
+ struct lrng_irq_info *irq_info = &pool->irq_info;
+ unsigned long flags;
+
+ u32 irq_num_events_used, irq_num_events, avail_entropy_bits;
+
+ /* This get_pool operation must only be called once at a given time! */
+ spin_lock_irqsave(&pool->lock, flags);
+
+ /* How many unused interrupts are in entropy pool? */
+ irq_num_events = atomic_read_u32(&irq_info->num_events);
+ /* Convert available interrupts into entropy statement */
+ avail_entropy_bits = lrng_data_to_entropy(irq_num_events);
+
+ /* Cap available entropy to pool size */
+ avail_entropy_bits =
+ min_t(u32, avail_entropy_bits, LRNG_POOL_SIZE_BITS);
+
+ /* How much entropy we need to and can we use? */
+ if (unlikely(!state->lrng_fully_seeded)) {
+ /*
+ * During boot time, we read 256 bits data with
+ * avail_entropy_bits entropy. In case our conservative
+ * entropy estimate underestimates the available entropy
+ * we can transport as much available entropy as
+ * possible. The entropy pool does not operate compliant to
+ * the German AIS 21/31 NTG.1 yet.
+ */
+ requested_entropy_bits =
+ LRNG_DRNG_SECURITY_STRENGTH_BITS;
+ } else {
+ /* Provide all entropy above retaining level */
+ if (avail_entropy_bits < entropy_retain) {
+ requested_entropy_bits = 0;
+ goto out;
+ }
+ avail_entropy_bits -= entropy_retain;
+ requested_entropy_bits = min_t(u32, avail_entropy_bits,
+ requested_entropy_bits);
+ }
+
+ /* Hash is a compression function: we generate entropy amount of data */
+ requested_entropy_bits = round_down(requested_entropy_bits, 8);
+
+ requested_entropy_bits = lrng_pool_hash_df(crypto_cb, hash, outbuf,
+ requested_entropy_bits);
+
+ /* Boot time: After getting the full buffer adjust the entropy value. */
+ requested_entropy_bits = min_t(u32, avail_entropy_bits,
+ requested_entropy_bits);
+
+out:
+ /* Convert used entropy into interrupt number for subtraction */
+ irq_num_events_used = lrng_entropy_to_data(requested_entropy_bits);
+
+ /*
+ * The hash_df operation entropy assessment shows that the output
+ * entropy is one bit smaller than the input entropy. Therefore we
+ * account for this one bit of entropy here: if we have sufficient
+ * entropy in the LFSR, we say we used one bit of entropy more.
+ * Otherwise we reduce the amount of entropy we say we generated with
+ * the hash_df.
+ */
+ if (irq_num_events_used) {
+ if ((irq_num_events_used + LRNG_CONDITIONING_ENTROPY_LOSS) <=
+ lrng_entropy_to_data(avail_entropy_bits)) {
+ irq_num_events_used += LRNG_CONDITIONING_ENTROPY_LOSS;
+ } else {
+ if (unlikely(requested_entropy_bits <
+ LRNG_CONDITIONING_ENTROPY_LOSS))
+ requested_entropy_bits = 0;
+ else
+ requested_entropy_bits -=
+ LRNG_CONDITIONING_ENTROPY_LOSS;
+ }
+ }
+
+ /*
+ * New events might have arrived in the meanwhile and we don't
+ * want to throw them away unconditionally. On the other hand,
+ * these new events might have been mixed in before
+ * lrng_hash_df_pool() had been able to draw any entropy
+ * from the pool and thus, the pool capacity might have been
+ * exceeded at some point. Note that in theory, some events
+ * might get lost inbetween the atomic_read() and
+ * atomic_set() below. But that's fine, because it's no real
+ * concern while code preventing this would come at the cost of
+ * additional complexity. Likewise, some events which arrived
+ * after full or partial completion of the __lrng_hash_df_pool()
+ * above might get unnecessarily thrown away by the min()
+ * operation below; the same argument applies there.
+ */
+ irq_num_events = atomic_read_u32(&irq_info->num_events);
+ irq_num_events = min_t(u32, irq_num_events,
+ lrng_entropy_to_data(LRNG_POOL_SIZE_BITS));
+ irq_num_events -= irq_num_events_used;
+ atomic_set(&irq_info->num_events, irq_num_events);
+
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ /* Obtain entropy statement in bits from the used entropy */
+ pr_debug("obtained %u bits of entropy from %u newly collected interrupts - not using %u interrupts\n",
+ requested_entropy_bits, irq_num_events_used,
+ irq_num_events);
+
+ return requested_entropy_bits;
+}
+
+/* Fill the seed buffer with data from the noise sources */
+int lrng_fill_seed_buffer(const struct lrng_crypto_cb *crypto_cb, void *hash,
+ struct entropy_buf *entropy_buf, u32 entropy_retain)
+{
+ struct lrng_state *state = &lrng_state;
+ u32 total_entropy_bits = 0;
+
+ /* Require at least 128 bits of entropy for any reseed. */
+ if (state->lrng_fully_seeded &&
+ (lrng_avail_entropy() <
+ lrng_slow_noise_req_entropy(LRNG_MIN_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS) +
+ entropy_retain))
+ goto wakeup;
+
+ /*
+ * Concatenate the output of the noise sources. This would be the
+ * spot to add an entropy extractor logic if desired. Note, this
+ * has the ability to collect entropy equal or larger than the DRNG
+ * strength.
+ */
+ total_entropy_bits = lrng_get_pool(crypto_cb, hash, entropy_buf->a,
+ LRNG_DRNG_SECURITY_STRENGTH_BITS,
+ entropy_retain);
+ total_entropy_bits += lrng_get_arch(entropy_buf->b);
+ total_entropy_bits += lrng_get_jent(entropy_buf->c,
+ LRNG_DRNG_SECURITY_STRENGTH_BYTES);
+
+ /* also reseed the DRNG with the current time stamp */
+ entropy_buf->now = random_get_entropy();
+
+ /* allow external entropy provider to provide seed */
+ lrng_state_exseed_allow_all();
+
+wakeup:
+ /*
+ * Shall we wake up user space writers? This location covers
+ * ensures that the user space provider does not dominate the internal
+ * noise sources since in case the first call of this function finds
+ * sufficient entropy in the entropy pool, it will not trigger the
+ * wakeup. This implies that when the next /dev/urandom read happens,
+ * the entropy pool is drained.
+ */
+ lrng_writer_wakeup();
+
+ return total_entropy_bits;
+}
+
+/**
+ * lrng_init_ops() - Set seed stages of LRNG
+ *
+ * Set the slow noise source reseed trigger threshold. The initial threshold
+ * is set to the minimum data size that can be read from the pool: a word. Upon
+ * reaching this value, the next seed threshold of 128 bits is set followed
+ * by 256 bits.
+ *
+ * @entropy_bits: size of entropy currently injected into DRNG
+ */
+void lrng_init_ops(u32 seed_bits)
+{
+ struct lrng_state *state = &lrng_state;
+
+ if (state->lrng_operational)
+ return;
+
+ /* DRNG is seeded with full security strength */
+ if (state->lrng_fully_seeded) {
+ state->lrng_operational = lrng_sp80090b_startup_complete();
+ lrng_process_ready_list();
+ lrng_init_wakeup();
+ } else if (seed_bits >= LRNG_FULL_SEED_ENTROPY_BITS) {
+ invalidate_batched_entropy();
+ state->lrng_fully_seeded = true;
+ state->lrng_operational = lrng_sp80090b_startup_complete();
+ state->lrng_min_seeded = true;
+ pr_info("LRNG fully seeded with %u bits of entropy\n",
+ seed_bits);
+ lrng_set_entropy_thresh(LRNG_FULL_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS);
+ lrng_process_ready_list();
+ lrng_init_wakeup();
+
+ } else if (!state->lrng_min_seeded) {
+
+ /* DRNG is seeded with at least 128 bits of entropy */
+ if (seed_bits >= LRNG_MIN_SEED_ENTROPY_BITS) {
+ invalidate_batched_entropy();
+ state->lrng_min_seeded = true;
+ pr_info("LRNG minimally seeded with %u bits of entropy\n",
+ seed_bits);
+ lrng_set_entropy_thresh(
+ lrng_slow_noise_req_entropy(
+ LRNG_FULL_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS));
+ lrng_process_ready_list();
+ lrng_init_wakeup();
+
+ /* DRNG is seeded with at least LRNG_INIT_ENTROPY_BITS bits */
+ } else if (seed_bits >= LRNG_INIT_ENTROPY_BITS) {
+ pr_info("LRNG initial entropy level %u bits of entropy\n",
+ seed_bits);
+ lrng_set_entropy_thresh(
+ lrng_slow_noise_req_entropy(
+ LRNG_MIN_SEED_ENTROPY_BITS +
+ LRNG_CONDITIONING_ENTROPY_LOSS));
+ }
+ }
+}
+
+int __init rand_initialize(void)
+{
+ ktime_t now_time = ktime_get_real();
+ unsigned long rand;
+ unsigned int i;
+
+ lrng_drng_init_early();
+
+ lrng_pool_lfsr_u32(now_time);
+ for (i = 0; i < LRNG_POOL_SIZE; i++) {
+ if (!arch_get_random_seed_long_early(&rand) &&
+ !arch_get_random_long_early(&rand))
+ rand = random_get_entropy();
+ lrng_pool_lfsr((u8 *)&rand, sizeof(rand));
+ }
+ lrng_pool_lfsr_nonaligned((u8 *)utsname(), sizeof(*(utsname())));
+
+ return 0;
+}
diff --git a/drivers/char/lrng/lrng_sw_noise.c b/drivers/char/lrng/lrng_sw_noise.c
new file mode 100644
index 000000000000..1183d77005ac
--- /dev/null
+++ b/drivers/char/lrng/lrng_sw_noise.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Slow Noise Source: Interrupt data collection
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#include <asm/irq_regs.h>
+#include <asm/ptrace.h>
+#include <linux/random.h>
+
+#include "lrng_internal.h"
+#include "lrng_sw_noise.h"
+
+/* Holder of time stamps before mixing them into the entropy pool */
+static DEFINE_PER_CPU(u32 [LRNG_TIME_ARRAY_SIZE], lrng_time);
+static DEFINE_PER_CPU(u32, lrng_time_ptr) = 0;
+static DEFINE_PER_CPU(u8, lrng_time_irqs) = 0;
+
+/*
+ * Batching up of entropy in per-CPU array before injecting into entropy pool.
+ *
+ * The random32_data is solely to be used for the external random32 PRNG.
+ */
+static inline void lrng_time_process(u32 random32_data)
+{
+ u32 i, ptr, now_time = random_get_entropy();
+ u32 now_time_masked = now_time & LRNG_TIME_SLOTSIZE_MASK;
+ enum lrng_health_res health_test;
+
+ /* Ensure sufficient space in lrng_time_irqs */
+ BUILD_BUG_ON(LRNG_TIME_NUM_VALUES >= (1 << (sizeof(u8) << 3)));
+ BUILD_BUG_ON(LRNG_TIME_ARRAY_MEMBER_BITS % LRNG_TIME_SLOTSIZE_BITS);
+ /* Ensure consistency of values */
+ BUILD_BUG_ON(LRNG_TIME_ARRAY_MEMBER_BITS != sizeof(lrng_time[0]) << 3);
+
+ /* During boot time, we mix the full time stamp directly into LFSR */
+ if (unlikely(!lrng_state_fully_seeded())) {
+
+ /* Seed random32 PRNG with data not used by LRNG. */
+ this_cpu_add(net_rand_state.s1, random32_data);
+
+ if (lrng_raw_hires_entropy_store(now_time))
+ goto out;
+
+ health_test = lrng_health_test(now_time);
+ if (health_test > lrng_health_fail_use)
+ goto out;
+
+ lrng_pool_lfsr_u32(now_time);
+ if (health_test == lrng_health_pass)
+ lrng_pool_add_irq(1);
+ goto out;
+ }
+
+ /* Runtime operation */
+ if (lrng_raw_hires_entropy_store(now_time_masked))
+ goto out;
+
+ /* Seed random32 PRNG with data not used by LRNG. */
+ this_cpu_add(net_rand_state.s1,
+ (now_time & ~LRNG_TIME_SLOTSIZE_MASK) ^ random32_data);
+
+ health_test = lrng_health_test(now_time_masked);
+ if (health_test > lrng_health_fail_use)
+ goto out;
+
+ ptr = this_cpu_inc_return(lrng_time_ptr) & LRNG_TIME_WORD_MASK;
+ this_cpu_or(lrng_time[lrng_time_idx2array(ptr)],
+ lrng_time_slot_val(now_time_masked,
+ lrng_time_idx2slot(ptr)));
+
+ /* Interrupt delivers entropy if health test passes */
+ if (health_test == lrng_health_pass)
+ this_cpu_inc(lrng_time_irqs);
+
+ /* Only mix the buffer of time stamps into LFSR when wrapping */
+ if (ptr < LRNG_TIME_WORD_MASK)
+ goto out;
+
+ for (i = 0; i < LRNG_TIME_ARRAY_SIZE; i++) {
+ if (lrng_raw_array_entropy_store(this_cpu_read(lrng_time[i]))) {
+ /*
+ * If we fed even a part of the array to external
+ * analysis, we mark that the entire array has no
+ * entropy. This is due to the non-IID property of
+ * the data as we do not fully know whether the
+ * existing dependencies diminish the entropy beyond
+ * to what we expect it has.
+ */
+ this_cpu_write(lrng_time_irqs, 0);
+ } else {
+ lrng_pool_lfsr_u32(this_cpu_read(lrng_time[i]));
+ }
+
+ this_cpu_write(lrng_time[i], 0);
+ }
+ lrng_pool_add_irq(this_cpu_read(lrng_time_irqs));
+ this_cpu_write(lrng_time_irqs, 0);
+
+out:
+ lrng_perf_time(now_time);
+}
+
+/*
+ * Hot code path - Callback for interrupt handler
+ */
+void add_interrupt_randomness(int irq, int irq_flags)
+{
+ if (lrng_pool_highres_timer()) {
+ lrng_time_process(
+ (lrng_raw_irq_entropy_store(irq) ? 0 : irq) ^
+ (lrng_raw_irqflags_entropy_store(irq_flags) ? 0 :
+ irq_flags) ^
+ (lrng_raw_retip_entropy_store(_RET_IP_) ? 0 :
+ _RET_IP_));
+ } else {
+ struct pt_regs *regs = get_irq_regs();
+ static atomic_t reg_idx = ATOMIC_INIT(0);
+ u64 ip;
+
+ if (regs) {
+ u32 *ptr = (u32 *)regs;
+ int reg_ptr = atomic_add_return_relaxed(1, ®_idx);
+ size_t n = (sizeof(struct pt_regs) / sizeof(u32));
+
+ ip = instruction_pointer(regs);
+ lrng_pool_lfsr_u32(*(ptr + (reg_ptr % n)));
+
+ lrng_time_process(
+ lrng_raw_retip_entropy_store(_RET_IP_) ? 0 :
+ _RET_IP_);
+ } else {
+ ip = _RET_IP_;
+
+ lrng_time_process(0);
+ }
+
+ /*
+ * The XOR operation combining the different values is not
+ * considered to destroy entropy since the entirety of all
+ * processed values delivers the entropy (and not each
+ * value separately of the other values).
+ */
+ lrng_pool_lfsr_u32(
+ (lrng_raw_jiffies_entropy_store(jiffies) ? 0 :
+ jiffies) ^
+ (lrng_raw_irq_entropy_store(irq) ? 0 : irq) ^
+ (lrng_raw_irqflags_entropy_store(irq_flags) ? 0 :
+ irq_flags) ^
+ (ip >> 32) ^
+ (lrng_raw_retip_entropy_store(ip) ? 0 : ip));
+ }
+}
+EXPORT_SYMBOL(add_interrupt_randomness);
diff --git a/drivers/char/lrng/lrng_sw_noise.h b/drivers/char/lrng/lrng_sw_noise.h
new file mode 100644
index 000000000000..919d8c368991
--- /dev/null
+++ b/drivers/char/lrng/lrng_sw_noise.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * LRNG Slow Noise Source: Time stamp array handling
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+/*
+ * To limit the impact on the interrupt handling, the LRNG concatenates
+ * entropic LSB parts of the time stamps in a per-CPU array and only
+ * injects them into the entropy pool when the array is full.
+ */
+
+/* Store multiple integers in one u32 */
+#define LRNG_TIME_SLOTSIZE_BITS (8)
+#define LRNG_TIME_SLOTSIZE_MASK ((1 << LRNG_TIME_SLOTSIZE_BITS) - 1)
+#define LRNG_TIME_ARRAY_MEMBER_BITS (4 << 3) /* ((sizeof(u32)) << 3) */
+#define LRNG_TIME_SLOTS_PER_UINT (LRNG_TIME_ARRAY_MEMBER_BITS / \
+ LRNG_TIME_SLOTSIZE_BITS)
+
+/*
+ * Number of time values to store in the array - in small environments
+ * only one atomic_t variable per CPU is used.
+ */
+#define LRNG_TIME_NUM_VALUES (CONFIG_BASE_SMALL ? \
+ LRNG_TIME_SLOTS_PER_UINT : 64)
+/* Mask of LSB of time stamp to store */
+#define LRNG_TIME_WORD_MASK (LRNG_TIME_NUM_VALUES - 1)
+
+#define LRNG_TIME_SLOTS_MASK (LRNG_TIME_SLOTS_PER_UINT - 1)
+#define LRNG_TIME_ARRAY_SIZE (LRNG_TIME_NUM_VALUES / \
+ LRNG_TIME_SLOTS_PER_UINT)
+
+/* Starting bit index of slot */
+static inline unsigned int lrng_time_slot2bitindex(unsigned int slot)
+{
+ return (LRNG_TIME_SLOTSIZE_BITS * slot);
+}
+
+/* Convert index into the array index */
+static inline unsigned int lrng_time_idx2array(unsigned int idx)
+{
+ return idx / LRNG_TIME_SLOTS_PER_UINT;
+}
+
+/* Convert index into the slot of a given array index */
+static inline unsigned int lrng_time_idx2slot(unsigned int idx)
+{
+ return idx & LRNG_TIME_SLOTS_MASK;
+}
+
+/* Convert value into slot value */
+static inline unsigned int lrng_time_slot_val(unsigned int val,
+ unsigned int slot)
+{
+ return val << lrng_time_slot2bitindex(slot);
+}
diff --git a/include/linux/lrng.h b/include/linux/lrng.h
new file mode 100644
index 000000000000..2c3d2ed32a91
--- /dev/null
+++ b/include/linux/lrng.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * Copyright (C) 2018 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#ifndef _LRNG_H
+#define _LRNG_H
+
+#include <linux/errno.h>
+#include <linux/types.h>
+
+/**
+ * struct lrng_crypto_cb - cryptographic callback functions
+ * @lrng_drng_name Name of DRNG
+ * @lrng_hash_name Name of Hash used for reading entropy pool
+ * @lrng_drng_alloc: Allocate DRNG -- the provided integer should be
+ * used for sanity checks.
+ * return: allocated data structure or PTR_ERR on
+ * error
+ * @lrng_drng_dealloc: Deallocate DRNG
+ * @lrng_drng_seed_helper: Seed the DRNG with data of arbitrary length
+ * drng: is pointer to data structure allocated
+ * with lrng_drng_alloc
+ * return: >= 0 on success, < 0 on error
+ * @lrng_drng_generate_helper: Generate random numbers from the DRNG with
+ * arbitrary length
+ * @lrng_hash_alloc: Allocate the hash for reading the entropy pool
+ * return: allocated data structure (NULL is
+ * success too) or ERR_PTR on error
+ * @lrng_hash_dealloc: Deallocate Hash
+ * @lrng_hash_digestsize: Return the digestsize for the used hash to read
+ * out entropy pool
+ * hash: is pointer to data structure allocated
+ * with lrng_hash_alloc
+ * return: size of digest of hash in bytes
+ * @lrng_hash_buffer: Generate hash
+ * hash: is pointer to data structure allocated
+ * with lrng_hash_alloc
+ * return: 0 on success, < 0 on error
+ */
+struct lrng_crypto_cb {
+ const char *(*lrng_drng_name)(void);
+ const char *(*lrng_hash_name)(void);
+ void *(*lrng_drng_alloc)(u32 sec_strength);
+ void (*lrng_drng_dealloc)(void *drng);
+ int (*lrng_drng_seed_helper)(void *drng, const u8 *inbuf, u32 inbuflen);
+ int (*lrng_drng_generate_helper)(void *drng, u8 *outbuf, u32 outbuflen);
+ void *(*lrng_hash_alloc)(const u8 *key, u32 keylen);
+ void (*lrng_hash_dealloc)(void *hash);
+ u32 (*lrng_hash_digestsize)(void *hash);
+ int (*lrng_hash_buffer)(void *hash, const u8 *inbuf, u32 inbuflen,
+ u8 *digest);
+};
+
+/* Register cryptographic backend */
+#ifdef CONFIG_LRNG_DRNG_SWITCH
+int lrng_set_drng_cb(const struct lrng_crypto_cb *cb);
+#else /* CONFIG_LRNG_DRNG_SWITCH */
+static inline int
+lrng_set_drng_cb(const struct lrng_crypto_cb *cb) { return -EOPNOTSUPP; }
+#endif /* CONFIG_LRNG_DRNG_SWITCH */
+
+#endif /* _LRNG_H */
--
2.26.2
In order to improve NUMA-locality when serving getrandom(2) requests,
allocate one DRNG instance per node.
The DRNG instance that is present right from the start of the kernel is
reused as the first per-NUMA-node DRNG. For all remaining online NUMA
nodes a new DRNG instance is allocated.
During boot time, the multiple DRNG instances are seeded sequentially.
With this, the first DRNG instance (referenced as the initial DRNG
in the code) is completely seeded with 256 bits of entropy before the
next DRNG instance is completely seeded.
When random numbers are requested, the NUMA-node-local DRNG is checked
whether it has been already fully seeded. If this is not the case, the
initial DRNG is used to serve the request.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Marcelo Henrique Cerri <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Makefile | 2 +
drivers/char/lrng/lrng_internal.h | 5 ++
drivers/char/lrng/lrng_numa.c | 101 ++++++++++++++++++++++++++++++
3 files changed, 108 insertions(+)
create mode 100644 drivers/char/lrng/lrng_numa.c
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index 1d2a0211973d..0a32f22c2c1a 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -7,3 +7,5 @@ obj-y += lrng_pool.o lrng_aux.o \
lrng_sw_noise.o lrng_archrandom.o \
lrng_drng.o lrng_chacha20.o \
lrng_interfaces.o \
+
+obj-$(CONFIG_NUMA) += lrng_numa.o
diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h
index f86afe8d2612..de034260c323 100644
--- a/drivers/char/lrng/lrng_internal.h
+++ b/drivers/char/lrng/lrng_internal.h
@@ -256,8 +256,13 @@ int lrng_drng_get_sleep(u8 *outbuf, u32 outbuflen);
void lrng_drng_force_reseed(void);
void lrng_drng_seed_work(struct work_struct *dummy);
+#ifdef CONFIG_NUMA
+struct lrng_drng **lrng_drng_instances(void);
+void lrng_drngs_numa_alloc(void);
+#else /* CONFIG_NUMA */
static inline struct lrng_drng **lrng_drng_instances(void) { return NULL; }
static inline void lrng_drngs_numa_alloc(void) { return; }
+#endif /* CONFIG_NUMA */
/************************** Health Test linking code **************************/
diff --git a/drivers/char/lrng/lrng_numa.c b/drivers/char/lrng/lrng_numa.c
new file mode 100644
index 000000000000..947c5b3ed517
--- /dev/null
+++ b/drivers/char/lrng/lrng_numa.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG NUMA support
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/lrng.h>
+#include <linux/slab.h>
+
+#include "lrng_internal.h"
+
+static struct lrng_drng **lrng_drng __read_mostly = NULL;
+
+struct lrng_drng **lrng_drng_instances(void)
+{
+ return lrng_drng;
+}
+
+/* Allocate the data structures for the per-NUMA node DRNGs */
+static void _lrng_drngs_numa_alloc(struct work_struct *work)
+{
+ struct lrng_drng **drngs;
+ struct lrng_drng *lrng_drng_init = lrng_drng_init_instance();
+ u32 node;
+ bool init_drng_used = false;
+
+ mutex_lock(&lrng_crypto_cb_update);
+
+ /* per-NUMA-node DRNGs are already present */
+ if (lrng_drng)
+ goto unlock;
+
+ drngs = kcalloc(nr_node_ids, sizeof(void *), GFP_KERNEL|__GFP_NOFAIL);
+ for_each_online_node(node) {
+ struct lrng_drng *drng;
+
+ if (!init_drng_used) {
+ drngs[node] = lrng_drng_init;
+ init_drng_used = true;
+ continue;
+ }
+
+ drng = kmalloc_node(sizeof(struct lrng_drng),
+ GFP_KERNEL|__GFP_NOFAIL, node);
+ memset(drng, 0, sizeof(lrng_drng));
+
+ drng->crypto_cb = lrng_drng_init->crypto_cb;
+ drng->drng = drng->crypto_cb->lrng_drng_alloc(
+ LRNG_DRNG_SECURITY_STRENGTH_BYTES);
+ if (IS_ERR(drng->drng)) {
+ kfree(drng);
+ goto err;
+ }
+
+ mutex_init(&drng->lock);
+ spin_lock_init(&drng->spin_lock);
+
+ /*
+ * No reseeding of NUMA DRNGs from previous DRNGs as this
+ * would complicate the code. Let it simply reseed.
+ */
+ lrng_drng_reset(drng);
+ drngs[node] = drng;
+
+ lrng_pool_inc_numa_node();
+ pr_info("DRNG for NUMA node %d allocated\n", node);
+ }
+
+ /* Ensure that all NUMA nodes receive changed memory here. */
+ mb();
+
+ if (!cmpxchg(&lrng_drng, NULL, drngs))
+ goto unlock;
+
+err:
+ for_each_online_node(node) {
+ struct lrng_drng *drng = drngs[node];
+
+ if (drng == lrng_drng_init)
+ continue;
+
+ if (drng) {
+ drng->crypto_cb->lrng_drng_dealloc(drng->drng);
+ kfree(drng);
+ }
+ }
+ kfree(drngs);
+
+unlock:
+ mutex_unlock(&lrng_crypto_cb_update);
+}
+
+static DECLARE_WORK(lrng_drngs_numa_alloc_work, _lrng_drngs_numa_alloc);
+
+void lrng_drngs_numa_alloc(void)
+{
+ schedule_work(&lrng_drngs_numa_alloc_work);
+}
--
2.26.2
The test interface allows a privileged process to capture the raw
unconditioned noise that is collected by the LRNG for statistical
analysis. Such testing allows the analysis how much entropy
the interrupt noise source provides on a given platform.
Extracted noise data is not used to seed the LRNG. This
is a test interface and not appropriate for production systems.
Yet, the interface is considered to be sufficiently secured for
production systems.
Access to the data is given through the lrng_raw debugfs file. The
data buffer should be multiples of sizeof(u32) to fill the entire
buffer. Using the option lrng_testing.boot_test=1 the raw noise of
the first 1000 entropy events since boot can be sampled.
This test interface allows generating the data required for
analysis whether the LRNG is in compliance with SP800-90B
sections 3.1.3 and 3.1.4.
In addition, the test interface allows gathering of the conatenated raw
entropy data to verify that the concatenation works appropriately.
This includes sampling of the following raw data:
* high-resolution time stamp
* Jiffies
* IRQ number
* IRQ flags
* return instruction pointer
* array logic batching the high-resolution time stamp
Finally, the execution duration for processing a time stamp can be
obtained with the LRNG raw entropy interface.
If a test interface is not compiled, its code is a noop which has no
impact on the performance.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Kconfig | 124 +++++++
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_testing.c | 575 +++++++++++++++++++++++++++++++
3 files changed, 700 insertions(+)
create mode 100644 drivers/char/lrng/lrng_testing.c
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
index 452ee4adb577..de20f189e297 100644
--- a/drivers/char/lrng/Kconfig
+++ b/drivers/char/lrng/Kconfig
@@ -164,4 +164,128 @@ config LRNG_APT_CUTOFF
default 325 if !LRNG_APT_BROKEN
default 32 if LRNG_APT_BROKEN
+menuconfig LRNG_TESTING_MENU
+ bool "LRNG testing interfaces"
+ depends on DEBUG_FS
+ help
+ Enable one or more of the following test interfaces.
+
+ If unsure, say N.
+
+if LRNG_TESTING_MENU
+
+config LRNG_RAW_HIRES_ENTROPY
+ bool "Enable entropy test interface to hires timer noise source"
+ default y
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned high resolution time stamp noise that
+ is collected by the LRNG for statistical analysis. Extracted
+ noise data is not used to seed the LRNG.
+
+ The raw noise data can be obtained using the lrng_raw_hires
+ debugfs file. Using the option lrng_testing.boot_raw_hires_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_JIFFIES_ENTROPY
+ bool "Enable entropy test interface to Jiffies noise source"
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned Jiffies that is collected by
+ the LRNG for statistical analysis. This data is used for
+ seeding the LRNG if a high-resolution time stamp is not
+ available. If a high-resolution time stamp is detected,
+ the Jiffies value is not collected by the LRNG and no
+ data is provided via the test interface. Extracted noise
+ data is not used to seed the random number generator.
+
+ The raw noise data can be obtained using the lrng_raw_jiffies
+ debugfs file. Using the option lrng_testing.boot_raw_jiffies_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_IRQ_ENTROPY
+ bool "Enable entropy test interface to IRQ number noise source"
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned interrupt number that is collected by
+ the LRNG for statistical analysis. This data is used for
+ seeding the random32 PRNG external to the LRNG if a
+ high-resolution time stamp is available or it will be used to
+ seed the LRNG otherwise. Extracted noise data is not used to
+ seed the random number generator.
+
+ The raw noise data can be obtained using the lrng_raw_irq
+ debugfs file. Using the option lrng_testing.boot_raw_irq_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_IRQFLAGS_ENTROPY
+ bool "Enable entropy test interface to IRQ flags noise source"
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned interrupt flags that is collected by
+ the LRNG for statistical analysis. This data is used for
+ seeding the random32 PRNG external to the LRNG if a
+ high-resolution time stamp is available or it will be used to
+ seed the LRNG otherwise. Extracted noise data is not used to
+ seed the random number generator.
+
+ The raw noise data can be obtained using the lrng_raw_irqflags
+ debugfs file. Using the option lrng_testing.boot_raw_irqflags_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_RETIP_ENTROPY
+ bool "Enable entropy test interface to RETIP value noise source"
+ help
+ The test interface allows a privileged process to capture
+ the raw unconditioned return instruction pointer value
+ that is collected by the LRNG for statistical analysis.
+ This data is used for seeding the random32 PRNG external
+ to the LRNG if a high-resolution time stamp is available or
+ it will be used to seed the LRNG otherwise. Extracted noise
+ data is not used to seed the random number generator.
+
+ The raw noise data can be obtained using the lrng_raw_retip
+ debugfs file. Using the option lrng_testing.boot_raw_retip_test=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_RAW_ARRAY
+ bool "Enable test interface to LRNG raw entropy storage array"
+ help
+ The test interface allows a privileged process to capture
+ the raw noise data that is collected by the LRNG
+ in the per-CPU array for statistical analysis. The purpose
+ of this interface is to verify that the array handling code
+ truly only concatenates data and provides the same entropy
+ rate as the raw unconditioned noise source when assessing
+ the collected data byte-wise.
+
+ The data can be obtained using the lrng_raw_array debugfs
+ file. Using the option lrng_testing.boot_raw_array=1
+ the raw noise of the first 1000 entropy events since boot
+ can be sampled.
+
+config LRNG_IRQ_PERF
+ bool "Enable LRNG interrupt performance monitor"
+ help
+ With this option, the performance monitor of the LRNG
+ interrupt handling code is enabled. The file provides
+ the execution time of the interrupt handler in
+ cycles.
+
+ The interrupt performance data can be obtained using
+ the lrng_irq_perf debugfs file. Using the option
+ lrng_testing.boot_irq_perf=1 the performance data of
+ the first 1000 entropy events since boot can be sampled.
+
+config LRNG_TESTING
+ bool
+ default y if (LRNG_RAW_HIRES_ENTROPY || LRNG_RAW_JIFFIES_ENTROPY ||LRNG_RAW_IRQ_ENTROPY || LRNG_RAW_IRQFLAGS_ENTROPY || LRNG_RAW_RETIP_ENTROPY || LRNG_RAW_ARRAY || LRNG_IRQ_PERF)
+
+endif #LRNG_TESTING_MENU
+
endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index c3008763dd14..b2ce1979dc4b 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o
obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o
obj-$(CONFIG_LRNG_JENT) += lrng_jent.o
obj-$(CONFIG_LRNG_HEALTH_TESTS) += lrng_health.o
+obj-$(CONFIG_LRNG_TESTING) += lrng_testing.o
diff --git a/drivers/char/lrng/lrng_testing.c b/drivers/char/lrng/lrng_testing.c
new file mode 100644
index 000000000000..a6e2c2b56fe2
--- /dev/null
+++ b/drivers/char/lrng/lrng_testing.c
@@ -0,0 +1,575 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Linux Random Number Generator (LRNG) testing interfaces
+ *
+ * Copyright (C) 2019 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/workqueue.h>
+#include <asm/errno.h>
+
+#include "lrng_internal.h"
+
+#define LRNG_TESTING_RINGBUFFER_SIZE 1024
+#define LRNG_TESTING_RINGBUFFER_MASK (LRNG_TESTING_RINGBUFFER_SIZE - 1)
+
+struct lrng_testing {
+ u32 lrng_testing_rb[LRNG_TESTING_RINGBUFFER_SIZE];
+ u32 rb_reader;
+ u32 rb_writer;
+ atomic_t lrng_testing_enabled;
+ spinlock_t lock;
+ wait_queue_head_t read_wait;
+};
+
+/*************************** Generic Data Handling ****************************/
+
+/*
+ * boot variable:
+ * 0 ==> No boot test, gathering of runtime data allowed
+ * 1 ==> Boot test enabled and ready for collecting data, gathering runtime
+ * data is disabled
+ * 2 ==> Boot test completed and disabled, gathering of runtime data is
+ * disabled
+ */
+
+static inline void lrng_testing_reset(struct lrng_testing *data)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&data->lock, flags);
+ data->rb_reader = 0;
+ data->rb_writer = 0;
+ spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static inline void lrng_testing_init(struct lrng_testing *data, u32 boot)
+{
+ /*
+ * The boot time testing implies we have a running test. If the
+ * caller wants to clear it, he has to unset the boot_test flag
+ * at runtime via sysfs to enable regular runtime testing
+ */
+ if (boot)
+ return;
+
+ lrng_testing_reset(data);
+ atomic_set(&data->lrng_testing_enabled, 1);
+ pr_warn("Enabling data collection\n");
+}
+
+static inline void lrng_testing_fini(struct lrng_testing *data)
+{
+ atomic_set(&data->lrng_testing_enabled, 0);
+ lrng_testing_reset(data);
+ pr_warn("Disabling data collection\n");
+}
+
+
+static inline bool lrng_testing_store(struct lrng_testing *data, u32 value,
+ u32 *boot)
+{
+ unsigned long flags;
+
+ if (!atomic_read(&data->lrng_testing_enabled) && (*boot != 1))
+ return false;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ /*
+ * Disable entropy testing for boot time testing after ring buffer
+ * is filled.
+ */
+ if (*boot) {
+ if (data->rb_writer > LRNG_TESTING_RINGBUFFER_SIZE) {
+ *boot = 2;
+ pr_warn_once("One time data collection test disabled\n");
+ spin_unlock_irqrestore(&data->lock, flags);
+ return false;
+ }
+
+ if (data->rb_writer == 1)
+ pr_warn("One time data collection test enabled\n");
+ }
+
+ data->lrng_testing_rb[data->rb_writer & LRNG_TESTING_RINGBUFFER_MASK] =
+ value;
+ data->rb_writer++;
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ if (wq_has_sleeper(&data->read_wait))
+ wake_up_interruptible(&data->read_wait);
+
+ return true;
+}
+
+static inline bool lrng_testing_have_data(struct lrng_testing *data)
+{
+ return ((data->rb_writer & LRNG_TESTING_RINGBUFFER_MASK) !=
+ (data->rb_reader & LRNG_TESTING_RINGBUFFER_MASK));
+}
+
+static inline int lrng_testing_reader(struct lrng_testing *data, u32 *boot,
+ u8 *outbuf, u32 outbuflen)
+{
+ unsigned long flags;
+ int collected_data = 0;
+
+ lrng_testing_init(data, *boot);
+
+ while (outbuflen) {
+ spin_lock_irqsave(&data->lock, flags);
+
+ /* We have no data or reached the writer. */
+ if (!data->rb_writer ||
+ (data->rb_writer == data->rb_reader)) {
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ /*
+ * Now we gathered all boot data, enable regular data
+ * collection.
+ */
+ if (*boot) {
+ *boot = 0;
+ goto out;
+ }
+
+ wait_event_interruptible(data->read_wait,
+ lrng_testing_have_data(data));
+ if (signal_pending(current)) {
+ collected_data = -ERESTARTSYS;
+ goto out;
+ }
+
+ continue;
+ }
+
+ /* We copy out word-wise */
+ if (outbuflen < sizeof(u32)) {
+ spin_unlock_irqrestore(&data->lock, flags);
+ goto out;
+ }
+
+ memcpy(outbuf, &data->lrng_testing_rb[data->rb_reader],
+ sizeof(u32));
+ data->rb_reader++;
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ outbuf += sizeof(u32);
+ outbuflen -= sizeof(u32);
+ collected_data += sizeof(u32);
+ }
+
+out:
+ if (!lrng_testing_have_data(data))
+ lrng_testing_fini(data);
+ return collected_data;
+}
+
+static int lrng_testing_extract_user(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *ppos,
+ int (*reader)(u8 *outbuf, u32 outbuflen))
+{
+ loff_t pos = *ppos;
+ u8 *tmp, *tmp_aligned;
+ int ret = 0, large_request = (nbytes > 256);
+
+ if (!nbytes)
+ return 0;
+
+ /*
+ * The intention of this interface is for collecting at least
+ * 1000 samples due to the SP800-90B requirements. So, we make no
+ * effort in avoiding allocating more memory that actually needed
+ * by the user. Hence, we allocate sufficient memory to always hold
+ * that amount of data.
+ */
+ tmp = kmalloc(LRNG_TESTING_RINGBUFFER_SIZE + sizeof(u32), GFP_KERNEL);
+ if (!tmp)
+ return -ENOMEM;
+
+ tmp_aligned = PTR_ALIGN(tmp, sizeof(u32));
+
+ while (nbytes) {
+ int i;
+
+ if (large_request && need_resched()) {
+ if (signal_pending(current)) {
+ if (ret == 0)
+ ret = -ERESTARTSYS;
+ break;
+ }
+ schedule();
+ }
+
+ i = min_t(int, nbytes, LRNG_TESTING_RINGBUFFER_SIZE);
+ i = reader(tmp_aligned, i);
+ if (i <= 0) {
+ if (i < 0)
+ ret = i;
+ break;
+ }
+ if (copy_to_user(buf, tmp_aligned, i)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ nbytes -= i;
+ buf += i;
+ ret += i;
+ }
+
+ kzfree(tmp);
+
+ nbytes -= ret;
+ *ppos = pos + nbytes;
+
+ return ret;
+}
+
+/************** Raw High-Resolution Timer Entropy Data Handling ***************/
+
+#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY
+
+static u32 boot_raw_hires_test = 0;
+module_param(boot_raw_hires_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_hires_test, "Enable gathering boot time high resolution timer entropy of the first entropy events");
+
+static struct lrng_testing lrng_raw_hires = {
+ .rb_reader = 0,
+ .rb_writer = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_hires.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_hires.read_wait)
+};
+
+bool lrng_raw_hires_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_hires, value, &boot_raw_hires_test);
+}
+
+static int lrng_raw_hires_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_hires, &boot_raw_hires_test,
+ outbuf, outbuflen);
+}
+
+static ssize_t lrng_raw_hires_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_hires_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_hires_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_hires_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_HIRES_ENTROPY */
+
+/********************* Raw Jiffies Entropy Data Handling **********************/
+
+#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY
+
+static u32 boot_raw_jiffies_test = 0;
+module_param(boot_raw_jiffies_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_jiffies_test, "Enable gathering boot time high resolution timer entropy of the first entropy events");
+
+static struct lrng_testing lrng_raw_jiffies = {
+ .rb_reader = 0,
+ .rb_writer = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_jiffies.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_jiffies.read_wait)
+};
+
+bool lrng_raw_jiffies_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_jiffies, value,
+ &boot_raw_jiffies_test);
+}
+
+static int lrng_raw_jiffies_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_jiffies, &boot_raw_jiffies_test,
+ outbuf, outbuflen);
+}
+
+static ssize_t lrng_raw_jiffies_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_jiffies_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_jiffies_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_jiffies_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_JIFFIES_ENTROPY */
+
+/************************** Raw IRQ Data Handling ****************************/
+
+#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY
+
+static u32 boot_raw_irq_test = 0;
+module_param(boot_raw_irq_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_irq_test, "Enable gathering boot time entropy of the first IRQ entropy events");
+
+static struct lrng_testing lrng_raw_irq = {
+ .rb_reader = 0,
+ .rb_writer = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_irq.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_irq.read_wait)
+};
+
+bool lrng_raw_irq_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_irq, value, &boot_raw_irq_test);
+}
+
+static int lrng_raw_irq_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_irq, &boot_raw_irq_test, outbuf,
+ outbuflen);
+}
+
+static ssize_t lrng_raw_irq_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_irq_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_irq_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_irq_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_IRQ_ENTROPY */
+
+/************************ Raw IRQFLAGS Data Handling **************************/
+
+#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY
+
+static u32 boot_raw_irqflags_test = 0;
+module_param(boot_raw_irqflags_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_irqflags_test, "Enable gathering boot time entropy of the first IRQ flags entropy events");
+
+static struct lrng_testing lrng_raw_irqflags = {
+ .rb_reader = 0,
+ .rb_writer = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_irqflags.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_irqflags.read_wait)
+};
+
+bool lrng_raw_irqflags_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_irqflags, value,
+ &boot_raw_irqflags_test);
+}
+
+static int lrng_raw_irqflags_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_irqflags, &boot_raw_irqflags_test,
+ outbuf, outbuflen);
+}
+
+static ssize_t lrng_raw_irqflags_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_irqflags_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_irqflags_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_irqflags_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY */
+
+/************************ Raw _RET_IP_ Data Handling **************************/
+
+#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY
+
+static u32 boot_raw_retip_test = 0;
+module_param(boot_raw_retip_test, uint, 0644);
+MODULE_PARM_DESC(boot_raw_retip_test, "Enable gathering boot time entropy of the first return instruction pointer entropy events");
+
+static struct lrng_testing lrng_raw_retip = {
+ .rb_reader = 0,
+ .rb_writer = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_retip.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_retip.read_wait)
+};
+
+bool lrng_raw_retip_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_retip, value, &boot_raw_retip_test);
+}
+
+static int lrng_raw_retip_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_retip, &boot_raw_retip_test,
+ outbuf, outbuflen);
+}
+
+static ssize_t lrng_raw_retip_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_retip_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_retip_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_retip_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_RETIP_ENTROPY */
+
+/********************** Raw Entropy Array Data Handling ***********************/
+
+#ifdef CONFIG_LRNG_RAW_ARRAY
+
+static u32 boot_raw_array = 0;
+module_param(boot_raw_array, uint, 0644);
+MODULE_PARM_DESC(boot_raw_array, "Enable gathering boot time raw noise array data of the first entropy events");
+
+static struct lrng_testing lrng_raw_array = {
+ .rb_reader = 0,
+ .rb_writer = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_raw_array.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_raw_array.read_wait)
+};
+
+bool lrng_raw_array_entropy_store(u32 value)
+{
+ return lrng_testing_store(&lrng_raw_array, value, &boot_raw_array);
+}
+
+static int lrng_raw_array_entropy_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_raw_array, &boot_raw_array, outbuf,
+ outbuflen);
+}
+
+static ssize_t lrng_raw_array_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_raw_array_entropy_reader);
+}
+
+static const struct file_operations lrng_raw_array_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_raw_array_read,
+};
+
+#endif /* CONFIG_LRNG_RAW_ARRAY */
+
+/******************** Interrupt Performance Data Handling *********************/
+
+#ifdef CONFIG_LRNG_IRQ_PERF
+
+static u32 boot_irq_perf = 0;
+module_param(boot_irq_perf, uint, 0644);
+MODULE_PARM_DESC(boot_irq_perf, "Enable gathering boot time interrupt performance data of the first entropy events");
+
+static struct lrng_testing lrng_irq_perf = {
+ .rb_reader = 0,
+ .rb_writer = 0,
+ .lock = __SPIN_LOCK_UNLOCKED(lrng_irq_perf.lock),
+ .read_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lrng_irq_perf.read_wait)
+};
+
+bool lrng_perf_time(u32 start)
+{
+ return lrng_testing_store(&lrng_irq_perf, random_get_entropy() - start,
+ &boot_irq_perf);
+}
+
+static int lrng_irq_perf_reader(u8 *outbuf, u32 outbuflen)
+{
+ return lrng_testing_reader(&lrng_irq_perf, &boot_irq_perf, outbuf,
+ outbuflen);
+}
+
+static ssize_t lrng_irq_perf_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ return lrng_testing_extract_user(file, to, count, ppos,
+ lrng_irq_perf_reader);
+}
+
+static const struct file_operations lrng_irq_perf_fops = {
+ .owner = THIS_MODULE,
+ .read = lrng_irq_perf_read,
+};
+
+#endif /* CONFIG_LRNG_IRQ_PERF */
+
+/**************************************************************************
+ * Debugfs interface
+ **************************************************************************/
+
+static int __init lrng_raw_init(void)
+{
+ struct dentry *lrng_raw_debugfs_root;
+
+ lrng_raw_debugfs_root = debugfs_create_dir(KBUILD_MODNAME, NULL);
+
+#ifdef CONFIG_LRNG_RAW_HIRES_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_hires", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_hires_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_JIFFIES_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_jiffies", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_jiffies_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_IRQ_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_irq", 0400, lrng_raw_debugfs_root,
+ NULL, &lrng_raw_irq_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_IRQFLAGS_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_irqflags", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_irqflags_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_RETIP_ENTROPY
+ debugfs_create_file_unsafe("lrng_raw_retip", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_retip_fops);
+#endif
+#ifdef CONFIG_LRNG_RAW_ARRAY
+ debugfs_create_file_unsafe("lrng_raw_array", 0400,
+ lrng_raw_debugfs_root, NULL,
+ &lrng_raw_array_fops);
+#endif
+#ifdef CONFIG_LRNG_IRQ_PERF
+ debugfs_create_file_unsafe("lrng_irq_perf", 0400, lrng_raw_debugfs_root,
+ NULL, &lrng_irq_perf_fops);
+#endif
+
+ return 0;
+}
+
+module_init(lrng_raw_init);
--
2.26.2
The LRNG sysctl interface provides the same controls as the existing
/dev/random implementation. These sysctls behave identically and are
implemented identically. The goal is to allow a possible merge of the
existing /dev/random implementation with this implementation which
implies that this patch tries have a very close similarity. Yet, all
sysctls are documented at [1].
In addition, it provides the file lrng_type which provides details about
the LRNG:
- the name of the DRNG that produces the random numbers for /dev/random,
/dev/urandom, getrandom(2)
- the hash used to produce random numbers from the entropy pool
- the number of secondary DRNG instances
- indicator whether the LRNG operates SP800-90B compliant
- indicator whether a high-resolution timer is identified - only with a
high-resolution timer the interrupt noise source will deliver sufficient
entropy
- indicator whether the LRNG has been minimally seeded (i.e. is the
secondary DRNG seeded with at least 128 bits of of entropy)
- indicator whether the LRNG has been fully seeded (i.e. is the
secondary DRNG seeded with at least 256 bits of entropy)
[1] https://www.chronox.de/lrng.html
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Marcelo Henrique Cerri <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_interfaces.c | 1 -
drivers/char/lrng/lrng_internal.h | 4 +
drivers/char/lrng/lrng_proc.c | 163 ++++++++++++++++++++++++++++
4 files changed, 168 insertions(+), 1 deletion(-)
create mode 100644 drivers/char/lrng/lrng_proc.c
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index 0a32f22c2c1a..e69c176f0161 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -9,3 +9,4 @@ obj-y += lrng_pool.o lrng_aux.o \
lrng_interfaces.o \
obj-$(CONFIG_NUMA) += lrng_numa.o
+obj-$(CONFIG_SYSCTL) += lrng_proc.o
diff --git a/drivers/char/lrng/lrng_interfaces.c b/drivers/char/lrng/lrng_interfaces.c
index ff8b73e4c936..78ebbfd20f0c 100644
--- a/drivers/char/lrng/lrng_interfaces.c
+++ b/drivers/char/lrng/lrng_interfaces.c
@@ -38,7 +38,6 @@ static DECLARE_WAIT_QUEUE_HEAD(lrng_write_wait);
static DECLARE_WAIT_QUEUE_HEAD(lrng_init_wait);
static struct fasync_struct *fasync;
-struct ctl_table random_table[];
/********************************** Helper ***********************************/
/* Is the DRNG seed level too low? */
diff --git a/drivers/char/lrng/lrng_internal.h b/drivers/char/lrng/lrng_internal.h
index de034260c323..4ccfe53e6ce9 100644
--- a/drivers/char/lrng/lrng_internal.h
+++ b/drivers/char/lrng/lrng_internal.h
@@ -117,7 +117,11 @@ void lrng_cc20_init_state_boot(struct chacha20_state *state);
/********************************** /proc *************************************/
+#ifdef CONFIG_SYSCTL
+void lrng_pool_inc_numa_node(void);
+#else
static inline void lrng_pool_inc_numa_node(void) { }
+#endif
/****************************** LRNG interfaces *******************************/
diff --git a/drivers/char/lrng/lrng_proc.c b/drivers/char/lrng/lrng_proc.c
new file mode 100644
index 000000000000..e5aba75968c1
--- /dev/null
+++ b/drivers/char/lrng/lrng_proc.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG proc and sysctl interfaces
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#include <linux/lrng.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/sysctl.h>
+#include <linux/uuid.h>
+
+#include "lrng_internal.h"
+
+/*
+ * This function is used to return both the bootid UUID, and random
+ * UUID. The difference is in whether table->data is NULL; if it is,
+ * then a new UUID is generated and returned to the user.
+ *
+ * If the user accesses this via the proc interface, the UUID will be
+ * returned as an ASCII string in the standard UUID format; if via the
+ * sysctl system call, as 16 bytes of binary data.
+ */
+static int lrng_proc_do_uuid(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct ctl_table fake_table;
+ unsigned char buf[64], tmp_uuid[16], *uuid;
+
+ uuid = table->data;
+ if (!uuid) {
+ uuid = tmp_uuid;
+ generate_random_uuid(uuid);
+ } else {
+ static DEFINE_SPINLOCK(bootid_spinlock);
+
+ spin_lock(&bootid_spinlock);
+ if (!uuid[8])
+ generate_random_uuid(uuid);
+ spin_unlock(&bootid_spinlock);
+ }
+
+ sprintf(buf, "%pU", uuid);
+
+ fake_table.data = buf;
+ fake_table.maxlen = sizeof(buf);
+
+ return proc_dostring(&fake_table, write, buffer, lenp, ppos);
+}
+
+static int lrng_proc_do_entropy(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct ctl_table fake_table;
+ int entropy_count;
+
+ entropy_count = lrng_avail_entropy();
+
+ fake_table.data = &entropy_count;
+ fake_table.maxlen = sizeof(entropy_count);
+
+ return proc_dointvec(&fake_table, write, buffer, lenp, ppos);
+}
+
+static int lrng_sysctl_poolsize = LRNG_POOL_SIZE_BITS;
+static int lrng_min_write_thresh;
+static int lrng_max_write_thresh = LRNG_POOL_SIZE_BITS;
+static char lrng_sysctl_bootid[16];
+static int lrng_drng_reseed_max_min;
+
+struct ctl_table random_table[] = {
+ {
+ .procname = "poolsize",
+ .data = &lrng_sysctl_poolsize,
+ .maxlen = sizeof(int),
+ .mode = 0444,
+ .proc_handler = proc_dointvec,
+ },
+ {
+ .procname = "entropy_avail",
+ .maxlen = sizeof(int),
+ .mode = 0444,
+ .proc_handler = lrng_proc_do_entropy,
+ },
+ {
+ .procname = "write_wakeup_threshold",
+ .data = &lrng_write_wakeup_bits,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &lrng_min_write_thresh,
+ .extra2 = &lrng_max_write_thresh,
+ },
+ {
+ .procname = "boot_id",
+ .data = &lrng_sysctl_bootid,
+ .maxlen = 16,
+ .mode = 0444,
+ .proc_handler = lrng_proc_do_uuid,
+ },
+ {
+ .procname = "uuid",
+ .maxlen = 16,
+ .mode = 0444,
+ .proc_handler = lrng_proc_do_uuid,
+ },
+ {
+ .procname = "urandom_min_reseed_secs",
+ .data = &lrng_drng_reseed_max_time,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ .extra1 = &lrng_drng_reseed_max_min,
+ },
+ { }
+};
+
+/* Number of online DRNGs */
+static u32 numa_drngs = 1;
+
+void lrng_pool_inc_numa_node(void)
+{
+ numa_drngs++;
+}
+
+static int lrng_proc_type_show(struct seq_file *m, void *v)
+{
+ struct lrng_drng *lrng_drng_init = lrng_drng_init_instance();
+ unsigned long flags = 0;
+ unsigned char buf[300];
+
+ lrng_drng_lock(lrng_drng_init, &flags);
+ snprintf(buf, sizeof(buf),
+ "DRNG name: %s\n"
+ "Hash for reading entropy pool: %s\n"
+ "DRNG security strength: %d bits\n"
+ "number of DRNG instances: %u\n"
+ "SP800-90B compliance: %s\n"
+ "High-resolution timer: %s\n"
+ "LRNG minimally seeded: %s\n"
+ "LRNG fully seeded: %s\n",
+ lrng_drng_init->crypto_cb->lrng_drng_name(),
+ lrng_drng_init->crypto_cb->lrng_hash_name(),
+ LRNG_DRNG_SECURITY_STRENGTH_BITS, numa_drngs,
+ lrng_sp80090b_compliant() ? "true" : "false",
+ lrng_pool_highres_timer() ? "true" : "false",
+ lrng_state_min_seeded() ? "true" : "false",
+ lrng_state_fully_seeded() ? "true" : "false");
+ lrng_drng_unlock(lrng_drng_init, &flags);
+
+ seq_write(m, buf, strlen(buf));
+
+ return 0;
+}
+
+static int __init lrng_proc_type_init(void)
+{
+ proc_create_single("lrng_type", 0444, NULL, &lrng_proc_type_show);
+ return 0;
+}
+
+module_init(lrng_proc_type_init);
--
2.26.2
Parts of the LRNG are already covered by self-tests, including:
* Self-test of SP800-90A DRBG provided by the Linux kernel crypto API.
* Self-test of the PRNG provided by the Linux kernel crypto API.
* Raw noise source data testing including SP800-90B compliant
tests when enabling CONFIG_LRNG_HEALTH_TESTS
This patch adds the self-tests for the remaining critical functions of
the LRNG that are essential to maintain entropy and provide
cryptographic strong random numbers. The following self-tests are
implemented:
* Self-test of the time array maintenance. This test verifies whether
the time stamp array management to store multiple values in one integer
implements a concatenation of the data.
* Self-test of the LFSR operation. This test injects a monotonic
increasing counter into the LFSR. After completion of the injection of
the counter, 3 pool words are compared with known good values. The known
good values are calculated with the newly-developed tool
lfsr_testvector_generation provided as part of the LRNG test tool set at
[1].
* Self-test of the Hash_DF operation ensures that this function operates
compliant to the specification. The self-test performs a Hash_DF
operation of a zeroized entropy pool state. The test vectors are
generated using the newly-developed tool hash_df_testvector_generation
provided as part of the LRNG test tool set at [1].
* Self-test of the ChaCha20 DRNG is based on the self-tests that are
already present and implemented with the stand-alone user space
ChaCha20 DRNG implementation available at [2]. The self-tests cover
different use cases of the DRNG seeded with known seed data.
The status of the LRNG self-tests is provided with the selftest_status
SysFS file. If the file contains a zero, the self-tests passed. The
value 0xffffffff means that the self-tests were not executed. Any other
value indicates a self-test failure.
The self-test may be compiled to panic the system if the self-test
fails.
All self-tests operate on private state data structures. This implies
that none of the self-tests have any impact on the regular LRNG
operations. This allows the self-tests to be repeated at runtime by
writing anything into the selftest_status SysFS file.
[1] https://www.chronox.de/lrng.html
[2] https://www.chronox.de/chacha20.html
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
CC: Marcelo Henrique Cerri <[email protected]>
CC: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Kconfig | 25 ++
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_selftest.c | 506 ++++++++++++++++++++++++++++++
3 files changed, 532 insertions(+)
create mode 100644 drivers/char/lrng/lrng_selftest.c
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
index de20f189e297..b75d809bed50 100644
--- a/drivers/char/lrng/Kconfig
+++ b/drivers/char/lrng/Kconfig
@@ -288,4 +288,29 @@ config LRNG_TESTING
endif #LRNG_TESTING_MENU
+config LRNG_SELFTEST
+ bool "Enable power-on and on-demand self-tests"
+ help
+ The power-on self-tests are executed during boot time
+ covering the ChaCha20 DRNG, the LFSR processing and the
+ time stamp management of the LRNG.
+
+ The on-demand self-tests are triggered by writing any
+ value into the SysFS file selftest_status. At the same
+ time, when reading this file, the test status is
+ returned. A zero indicates that all tests were executed
+ successfully.
+
+ If unsure, say Y.
+
+if LRNG_SELFTEST
+
+config LRNG_SELFTEST_PANIC
+ bool "Panic the kernel upon self-test failure"
+ help
+ If the option is enabled, the kernel is terminated if an
+ LRNG power-on self-test failure is detected.
+
+endif # LRNG_SELFTEST
+
endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index b2ce1979dc4b..92219c565f66 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -16,3 +16,4 @@ obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o
obj-$(CONFIG_LRNG_JENT) += lrng_jent.o
obj-$(CONFIG_LRNG_HEALTH_TESTS) += lrng_health.o
obj-$(CONFIG_LRNG_TESTING) += lrng_testing.o
+obj-$(CONFIG_LRNG_SELFTEST) += lrng_selftest.o
diff --git a/drivers/char/lrng/lrng_selftest.c b/drivers/char/lrng/lrng_selftest.c
new file mode 100644
index 000000000000..74a529b15fa5
--- /dev/null
+++ b/drivers/char/lrng/lrng_selftest.c
@@ -0,0 +1,506 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG power-on and on-demand self-test
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+/*
+ * In addition to the self-tests below, the following LRNG components
+ * are covered with self-tests during regular operation:
+ *
+ * * power-on self-test: SP800-90A DRBG provided by the Linux kernel crypto API
+ * * power-on self-test: PRNG provided by the Linux kernel crypto API
+ * * runtime test: Raw noise source data testing including SP800-90B compliant
+ * tests when enabling CONFIG_LRNG_HEALTH_TESTS
+ *
+ * Additional developer tests present with LRNG code:
+ * * SP800-90B APT and RCT test enforcement validation when enabling
+ * CONFIG_LRNG_APT_BROKEN or CONFIG_LRNG_RCT_BROKEN.
+ * * Collection of raw entropy from the interrupt noise source when enabling
+ * CONFIG_LRNG_TESTING and pulling the data from the kernel with the provided
+ * interface.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/lrng.h>
+#include <linux/slab.h>
+
+#include "lrng_chacha20.h"
+#include "lrng_internal.h"
+#include "lrng_lfsr.h"
+#include "lrng_sw_noise.h"
+
+#define LRNG_SELFTEST_PASSED 0
+#define LRNG_SEFLTEST_ERROR_TIME (1 << 0)
+#define LRNG_SEFLTEST_ERROR_LFSR (1 << 1)
+#define LRNG_SEFLTEST_ERROR_CHACHA20 (1 << 2)
+#define LRNG_SEFLTEST_ERROR_HASHDF (1 << 3)
+#define LRNG_SELFTEST_NOT_EXECUTED 0xffffffff
+
+static u32 lrng_time_selftest[LRNG_TIME_ARRAY_SIZE];
+
+static unsigned int lrng_selftest_status = LRNG_SELFTEST_NOT_EXECUTED;
+
+static inline void lrng_selftest_bswap32(u32 *ptr, u32 words)
+{
+ u32 i;
+
+ /* Byte-swap data which is an LE representation */
+ for (i = 0; i < words; i++) {
+ __le32 *p = (__le32 *)ptr;
+
+ *p = cpu_to_le32(*ptr);
+ ptr++;
+ }
+}
+
+static inline void lrng_time_process_selftest_insert(u32 time)
+{
+ static u32 lrng_time_selftest_ptr = 0;
+ u32 ptr = lrng_time_selftest_ptr++ & LRNG_TIME_WORD_MASK;
+
+ lrng_time_selftest[lrng_time_idx2array(ptr)] |=
+ lrng_time_slot_val(time & LRNG_TIME_SLOTSIZE_MASK,
+ lrng_time_idx2slot(ptr));
+}
+
+static unsigned int lrng_time_process_selftest(void)
+{
+ u32 time;
+ u32 idx_zero_compare = (0 << 0) | (1 << 8) | (2 << 16) | (3 << 24);
+ u32 idx_one_compare = (4 << 0) | (5 << 8) | (6 << 16) | (7 << 24);
+ u32 idx_last_compare = ((LRNG_TIME_NUM_VALUES - 4) << 0) |
+ ((LRNG_TIME_NUM_VALUES - 3) << 8) |
+ ((LRNG_TIME_NUM_VALUES - 2) << 16) |
+ ((LRNG_TIME_NUM_VALUES - 1) << 24);
+
+ (void)idx_one_compare;
+
+ for (time = 0; time < LRNG_TIME_NUM_VALUES; time++)
+ lrng_time_process_selftest_insert(time);
+
+ if ((lrng_time_selftest[0] != idx_zero_compare) ||
+#if (LRNG_TIME_ARRAY_SIZE > 1)
+ (lrng_time_selftest[1] != idx_one_compare) ||
+#endif
+ (lrng_time_selftest[LRNG_TIME_ARRAY_SIZE - 1] != idx_last_compare))
+ {
+ pr_err("LRNG time array self-test FAILED\n");
+ return LRNG_SEFLTEST_ERROR_TIME;
+ }
+
+ return LRNG_SELFTEST_PASSED;
+}
+
+/*
+ * The test vectors are generated with the lfsr_testvector_generation tool
+ * provided as part of the test tool set of the LRNG.
+ */
+static unsigned int lrng_pool_lfsr_selftest(void)
+{
+ /*
+ * First, 67th and last entry of entropy pool.
+ *
+ * The 67th entry is picked because this one is the first to receive
+ * an entry. As we start with 1 to inject into the LFSR, the
+ * 67th entry should be equal to rol(1, 7) >> 3 considering that
+ * all other values of the LFSR are zero and the the twist value of 0
+ * is applied.
+ */
+ static const u32 lrng_lfsr_selftest_result[][3] = {
+ { 0xf56df24a, 0x00000010, 0x0e014939 },
+ { 0x4b130726, 0x00000010, 0x2802f509 },
+ { 0x87279152, 0x00000010, 0x00150000 },
+ { 0x0b67f997, 0x00000010, 0x00150000 },
+ { 0x4fea174f, 0x00000010, 0xcbf4a6ae },
+ { 0x77149108, 0x00000010, 0x77bfadf2 },
+ { 0x1e96037e, 0x00000010, 0x18017e79 },
+ { 0xc84acef2, 0x00000010, 0x6345f7a8 },
+ { 0x6a2eb6df, 0x00000010, 0x03950000 },
+ };
+ struct lrng_pool *lrng_pool, *lrng_pool_aligned;
+ u32 i, ret = LRNG_SELFTEST_PASSED;
+
+ BUILD_BUG_ON(ARRAY_SIZE(lrng_lfsr_selftest_result) <
+ CONFIG_LRNG_POOL_SIZE);
+
+ lrng_pool = kzalloc(sizeof(struct lrng_pool) + LRNG_KCAPI_ALIGN,
+ GFP_KERNEL);
+ if (!lrng_pool)
+ return LRNG_SEFLTEST_ERROR_LFSR;
+ lrng_pool_aligned = PTR_ALIGN(lrng_pool, sizeof(u32));
+
+ for (i = 1; i <= LRNG_POOL_SIZE; i++)
+ _lrng_pool_lfsr_u32(lrng_pool_aligned, i);
+
+ if ((atomic_read_u32(&lrng_pool_aligned->pool[0]) !=
+ lrng_lfsr_selftest_result[CONFIG_LRNG_POOL_SIZE][0]) ||
+ (atomic_read_u32(&lrng_pool_aligned->pool[67 &
+ (LRNG_POOL_SIZE - 1)]) !=
+ lrng_lfsr_selftest_result[CONFIG_LRNG_POOL_SIZE][1]) ||
+ (atomic_read_u32(&lrng_pool_aligned->pool[LRNG_POOL_SIZE - 1]) !=
+ lrng_lfsr_selftest_result[CONFIG_LRNG_POOL_SIZE][2])) {
+ pr_err("LRNG LFSR self-test FAILED\n");
+ ret = LRNG_SEFLTEST_ERROR_LFSR;
+ }
+
+ kfree(lrng_pool);
+ return ret;
+}
+
+/*
+ * The test vectors are generated with the hash_df_testvector_generation tool
+ * provided as part of the test tool set of the LRNG.
+ */
+static unsigned int lrng_hash_df_selftest(void)
+{
+ const struct lrng_crypto_cb *crypto_cb = &lrng_cc20_crypto_cb;
+
+ /*
+ * The size of 44 bytes is chosen arbitrarily. Yet, this size should
+ * ensure that we have at least one hash block plus some fraction
+ * of a hash block generated.
+ */
+ static const u8 lrng_hash_df_selftest_result[][44] = {
+#ifdef CONFIG_CRYPTO_LIB_SHA256
+ {
+ 0x71, 0xd6, 0xcb, 0xad, 0xdd, 0xdd, 0xe5, 0xec,
+ 0xe7, 0x31, 0x12, 0x3e, 0x29, 0x17, 0x6a, 0x43,
+ 0x71, 0xb6, 0x2c, 0x07, 0xf8, 0x40, 0x3e, 0xe1,
+ 0x0b, 0x91, 0xb8, 0xea, 0xac, 0xda, 0x4c, 0x71,
+ 0xdc, 0xe7, 0x26, 0xde, 0x71, 0x51, 0x46, 0xa5,
+ 0xab, 0x49, 0x85, 0x9c,
+ }, {
+ 0x85, 0x42, 0x04, 0xa4, 0x37, 0xf9, 0xb9, 0xc3,
+ 0xf8, 0x9c, 0x07, 0x96, 0x23, 0x18, 0x61, 0x39,
+ 0x8b, 0x2f, 0xfb, 0xa5, 0x63, 0x25, 0xcc, 0x7b,
+ 0x6f, 0x27, 0xf9, 0x13, 0xa3, 0x0a, 0xe9, 0x05,
+ 0x17, 0x08, 0x3a, 0xda, 0xca, 0xb6, 0x68, 0x83,
+ 0xe4, 0x32, 0xed, 0x20,
+ }, {
+ 0xca, 0xe7, 0xbe, 0x63, 0x8c, 0x48, 0x59, 0xe1,
+ 0x42, 0xfb, 0x79, 0x6c, 0x79, 0xd5, 0x57, 0x35,
+ 0x64, 0xfd, 0x84, 0x42, 0x96, 0x30, 0xcf, 0x37,
+ 0x7d, 0x4b, 0x7b, 0xbe, 0xff, 0xa6, 0xb5, 0x77,
+ 0x15, 0xa8, 0xdb, 0x30, 0x38, 0xcd, 0xc2, 0x59,
+ 0xf2, 0x0e, 0xba, 0xce,
+ }, {
+ 0x7d, 0xf6, 0xe0, 0x6f, 0x55, 0xa9, 0xc3, 0x5d,
+ 0xe4, 0xab, 0xec, 0x7d, 0xc8, 0x25, 0x44, 0xcc,
+ 0xcb, 0x53, 0x98, 0xbe, 0x10, 0x9d, 0x8f, 0x7d,
+ 0x37, 0xcf, 0xf8, 0xe4, 0xa6, 0x65, 0x29, 0xa2,
+ 0x4e, 0x40, 0x53, 0xe9, 0xe6, 0xdc, 0x49, 0xeb,
+ 0xc0, 0xb2, 0xbf, 0x59,
+ }, {
+ 0x3e, 0xe5, 0x11, 0x25, 0xda, 0xc1, 0xff, 0x49,
+ 0x99, 0xaf, 0x62, 0xc0, 0x7b, 0x98, 0xd7, 0xd9,
+ 0xc4, 0x88, 0xf6, 0x1f, 0x6e, 0xca, 0x93, 0x4c,
+ 0xb3, 0x43, 0x2f, 0x95, 0x6c, 0x9b, 0x19, 0x24,
+ 0x5f, 0x73, 0xc3, 0xff, 0xbc, 0xec, 0x58, 0x2c,
+ 0x6f, 0x55, 0xb0, 0x1c,
+ }, {
+ 0xbb, 0x59, 0x3a, 0xbd, 0xf7, 0xa0, 0x2b, 0x7b,
+ 0x20, 0x76, 0xe6, 0x2e, 0x5d, 0x73, 0x13, 0xd7,
+ 0xb0, 0x42, 0xbe, 0x61, 0x07, 0x3c, 0xc9, 0x50,
+ 0x15, 0x69, 0xe6, 0x70, 0xe3, 0xb6, 0x61, 0xe2,
+ 0x41, 0x6f, 0x05, 0xe4, 0x24, 0xb4, 0xd9, 0x21,
+ 0xb1, 0xab, 0xb7, 0x36,
+ }, {
+ 0x19, 0xc2, 0x04, 0x31, 0x33, 0xf7, 0x25, 0xf4,
+ 0x7c, 0x44, 0x9e, 0xd9, 0x7f, 0x06, 0x80, 0x8b,
+ 0xc7, 0xe9, 0x3d, 0xa4, 0xeb, 0x9d, 0x07, 0x99,
+ 0x3b, 0x94, 0x31, 0x3e, 0xa0, 0xcd, 0x86, 0x04,
+ 0x37, 0x6d, 0x1f, 0xc9, 0x9e, 0x66, 0x2b, 0x64,
+ 0xbb, 0xd7, 0x77, 0x32,
+ }, {
+ 0x06, 0xac, 0xb6, 0xc1, 0xf5, 0xcf, 0x25, 0x2d,
+ 0x91, 0xba, 0x78, 0x9f, 0x1f, 0x4a, 0x63, 0xbb,
+ 0xae, 0x42, 0xf7, 0xb9, 0xac, 0x20, 0x35, 0xfe,
+ 0x89, 0x81, 0x7f, 0x90, 0x94, 0xcf, 0xe1, 0x95,
+ 0x33, 0x06, 0xaa, 0x67, 0xb6, 0x2e, 0x3c, 0x5c,
+ 0x72, 0x55, 0x9c, 0x2f,
+ }, {
+ 0x4e, 0x8b, 0x94, 0x76, 0x37, 0xe0, 0x42, 0x41,
+ 0x69, 0xd2, 0xc8, 0x7d, 0xd7, 0x58, 0x76, 0x3a,
+ 0xb9, 0xbf, 0xb3, 0xcf, 0xf2, 0xbd, 0x2e, 0x84,
+ 0x13, 0xe7, 0x55, 0x90, 0x55, 0x80, 0x50, 0x7a,
+ 0x19, 0xc3, 0x0c, 0x18, 0x0b, 0x6b, 0x66, 0xb7,
+ 0x43, 0x6c, 0xfe, 0x63,
+ }
+#else /* CONFIG_CRYPTO_LIB_SHA256 */
+ {
+ 0x65, 0x48, 0xc4, 0xb3, 0x4d, 0x9c, 0xec, 0xd7,
+ 0x69, 0x72, 0xf7, 0x8b, 0x35, 0x23, 0xa8, 0x9a,
+ 0xb2, 0xe8, 0x83, 0xf8, 0xba, 0x32, 0x76, 0xae,
+ 0xed, 0xe2, 0x94, 0x6a, 0x93, 0x99, 0x6e, 0xce,
+ 0xd5, 0xb5, 0xc5, 0x16, 0xa7, 0x8d, 0xc8, 0xd3,
+ 0xe9, 0xdd, 0x4f, 0xca,
+ }, {
+ 0x50, 0xcc, 0x6f, 0xe9, 0x40, 0x20, 0x40, 0x3e,
+ 0xce, 0x42, 0x3e, 0x30, 0x87, 0xf1, 0x3d, 0x60,
+ 0x75, 0xdd, 0x4f, 0x33, 0x06, 0x75, 0xbf, 0x5e,
+ 0x4c, 0x88, 0xc0, 0x60, 0x0f, 0x9d, 0xf9, 0xa5,
+ 0x63, 0xb1, 0xac, 0xc7, 0x32, 0x22, 0x60, 0xea,
+ 0x88, 0xe7, 0x61, 0x8b,
+ }, {
+ 0x09, 0x96, 0xbe, 0x89, 0x16, 0x5e, 0x41, 0x82,
+ 0xf3, 0xab, 0xf6, 0x11, 0xef, 0x45, 0x0e, 0x87,
+ 0x72, 0x38, 0x40, 0xe4, 0x21, 0x0b, 0x1c, 0x45,
+ 0x25, 0x9c, 0x26, 0x34, 0x7e, 0xad, 0x25, 0x33,
+ 0xf2, 0xb0, 0xc5, 0xa7, 0x0b, 0x38, 0xd9, 0x89,
+ 0x02, 0x08, 0xa2, 0x5b,
+ }, {
+ 0x10, 0x5b, 0xf4, 0x5b, 0xa9, 0xfc, 0x83, 0x2d,
+ 0x82, 0xf8, 0xa1, 0x17, 0x34, 0xe2, 0x67, 0xb7,
+ 0x95, 0xe2, 0x63, 0x2d, 0x1b, 0xf6, 0x59, 0x05,
+ 0x49, 0x9a, 0x3f, 0xa1, 0x16, 0xf7, 0x42, 0xd1,
+ 0x9c, 0x29, 0x5e, 0x31, 0xc9, 0x42, 0xf8, 0x9d,
+ 0x9b, 0x35, 0xd2, 0x30,
+ }, {
+ 0x1e, 0x43, 0xfe, 0x8a, 0x66, 0x53, 0x2d, 0x94,
+ 0x68, 0xbe, 0xfc, 0xc6, 0xfa, 0x95, 0x4a, 0xca,
+ 0xa7, 0x54, 0xcd, 0x92, 0xc9, 0xca, 0xcc, 0x4f,
+ 0xb2, 0xc5, 0xc5, 0xb6, 0x17, 0xd7, 0xb5, 0x41,
+ 0xa0, 0x8e, 0xef, 0x75, 0x00, 0x96, 0x8e, 0x13,
+ 0x8c, 0x9f, 0xd6, 0xce,
+ }, {
+ 0x70, 0x14, 0x94, 0x45, 0xa3, 0xb6, 0xac, 0xef,
+ 0x22, 0xe3, 0xe4, 0x2a, 0x38, 0x8c, 0x0e, 0x45,
+ 0x17, 0x61, 0x4e, 0x1d, 0xb3, 0xaf, 0xc1, 0xee,
+ 0x60, 0x31, 0x4d, 0xdc, 0xe1, 0x83, 0x8b, 0x85,
+ 0x97, 0x27, 0x30, 0x24, 0x57, 0xc2, 0xfd, 0xc0,
+ 0x99, 0x4b, 0xad, 0xb1,
+ }, {
+ 0x12, 0x87, 0x51, 0x68, 0x28, 0xab, 0xa9, 0xd1,
+ 0x91, 0x64, 0x5e, 0x38, 0x7f, 0xf3, 0xaf, 0xd5,
+ 0x93, 0xbc, 0x31, 0xfd, 0xae, 0x19, 0x45, 0xd7,
+ 0x1f, 0xe8, 0x0c, 0x24, 0xa6, 0x6d, 0x09, 0x0b,
+ 0x17, 0x44, 0xdb, 0xce, 0x1c, 0x0a, 0xdb, 0x73,
+ 0x7a, 0x91, 0x33, 0x4c,
+ }, {
+ 0x14, 0x81, 0x76, 0x37, 0x27, 0x19, 0x8d, 0x71,
+ 0xcc, 0x2e, 0xa3, 0x71, 0x92, 0x46, 0x6e, 0x3a,
+ 0xac, 0x87, 0xd6, 0x1e, 0xa7, 0xa9, 0x2e, 0x1e,
+ 0xd9, 0x6c, 0xea, 0xbe, 0x1a, 0x2e, 0xe9, 0x8a,
+ 0x96, 0x2a, 0xe3, 0xee, 0xd2, 0x25, 0xb2, 0xae,
+ 0xc6, 0xba, 0xe7, 0xef,
+ }, {
+ 0x58, 0x78, 0xce, 0xcb, 0xcf, 0x61, 0xc2, 0x3d,
+ 0x00, 0x80, 0x74, 0x57, 0x56, 0x44, 0xc7, 0xe2,
+ 0x9a, 0xed, 0x30, 0x02, 0x3f, 0x9a, 0xf5, 0xcc,
+ 0xf7, 0x7b, 0x40, 0xf7, 0x10, 0x97, 0x8d, 0x8f,
+ 0x58, 0xa4, 0x80, 0x88, 0x87, 0x30, 0x87, 0x7b,
+ 0xac, 0x2e, 0xce, 0x0d,
+ }
+#endif /* CONFIG_CRYPTO_LIB_SHA256 */
+ };
+ struct lrng_pool *lrng_pool, *lrng_pool_aligned;
+ u8 hash_df[sizeof(lrng_hash_df_selftest_result[0])]
+ __aligned(sizeof(u32));
+ u32 generated;
+ int ret = 0;
+
+ BUILD_BUG_ON(ARRAY_SIZE(lrng_hash_df_selftest_result) <
+ CONFIG_LRNG_POOL_SIZE);
+ /* Calculated data needs to be byte-swapped */
+ BUILD_BUG_ON(sizeof(lrng_hash_df_selftest_result[0]) % sizeof(32));
+
+ lrng_pool = kzalloc(sizeof(struct lrng_pool) + LRNG_KCAPI_ALIGN,
+ GFP_KERNEL);
+ if (!lrng_pool)
+ return LRNG_SEFLTEST_ERROR_HASHDF;
+ lrng_pool_aligned = PTR_ALIGN(lrng_pool, sizeof(u32));
+
+ generated = __lrng_pool_hash_df(crypto_cb, NULL, lrng_pool_aligned,
+ hash_df, sizeof(hash_df) << 3);
+
+ lrng_selftest_bswap32((u32 *)hash_df,
+ sizeof(lrng_hash_df_selftest_result[0]) / sizeof(u32));
+
+ if ((generated >> 3) != sizeof(hash_df) ||
+ memcmp(hash_df, lrng_hash_df_selftest_result[CONFIG_LRNG_POOL_SIZE],
+ sizeof(hash_df))) {
+ pr_err("LRNG Hash DF self-test FAILED\n");
+ ret = LRNG_SEFLTEST_ERROR_HASHDF;
+ }
+
+ kfree(lrng_pool);
+ return ret;
+}
+
+/*
+ * The test vectors were generated using the ChaCha20 DRNG from
+ * https://www.chronox.de/chacha20.html
+ */
+static unsigned int lrng_chacha20_drng_selftest(void)
+{
+ const struct lrng_crypto_cb *crypto_cb = &lrng_cc20_crypto_cb;
+ u8 seed[CHACHA_KEY_SIZE * 2] = {
+ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+ 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+ 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+ 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+ 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
+ 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
+ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
+ 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
+ };
+ struct chacha20_block chacha20;
+ int ret;
+ u8 outbuf[CHACHA_KEY_SIZE * 2] __aligned(sizeof(u32));
+
+ /*
+ * Expected result when ChaCha20 DRNG state is zero:
+ * * constants are set to "expand 32-byte k"
+ * * remaining state is 0
+ * and pulling one half ChaCha20 DRNG block.
+ */
+ static const u8 expected_halfblock[CHACHA_KEY_SIZE] = {
+ 0x76, 0xb8, 0xe0, 0xad, 0xa0, 0xf1, 0x3d, 0x90,
+ 0x40, 0x5d, 0x6a, 0xe5, 0x53, 0x86, 0xbd, 0x28,
+ 0xbd, 0xd2, 0x19, 0xb8, 0xa0, 0x8d, 0xed, 0x1a,
+ 0xa8, 0x36, 0xef, 0xcc, 0x8b, 0x77, 0x0d, 0xc7 };
+
+ /*
+ * Expected result when ChaCha20 DRNG state is zero:
+ * * constants are set to "expand 32-byte k"
+ * * remaining state is 0
+ * followed by a reseed with two keyblocks
+ * 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+ * 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+ * 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+ * 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+ * 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
+ * 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
+ * 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
+ * 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f
+ * and pulling one ChaCha20 DRNG block.
+ */
+ static const u8 expected_oneblock[CHACHA_KEY_SIZE * 2] = {
+ 0xf5, 0xb4, 0xb6, 0x5a, 0xec, 0xcd, 0x5a, 0x65,
+ 0x87, 0x56, 0xe3, 0x86, 0x51, 0x54, 0xfc, 0x90,
+ 0x56, 0xff, 0x5e, 0xae, 0x58, 0xf2, 0x01, 0x88,
+ 0xb1, 0x7e, 0xb8, 0x2e, 0x17, 0x9a, 0x27, 0xe6,
+ 0x86, 0xb3, 0xed, 0x33, 0xf7, 0xb9, 0x06, 0x05,
+ 0x8a, 0x2d, 0x1a, 0x93, 0xc9, 0x0b, 0x80, 0x04,
+ 0x03, 0xaa, 0x60, 0xaf, 0xd5, 0x36, 0x40, 0x11,
+ 0x67, 0x89, 0xb1, 0x66, 0xd5, 0x88, 0x62, 0x6d };
+
+ /*
+ * Expected result when ChaCha20 DRNG state is zero:
+ * * constants are set to "expand 32-byte k"
+ * * remaining state is 0
+ * followed by a reseed with one key block plus one byte
+ * 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+ * 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+ * 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+ * 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+ * 0x20
+ * and pulling less than one ChaCha20 DRNG block.
+ */
+ static const u8 expected_block_nonalinged[CHACHA_KEY_SIZE + 4] = {
+ 0x9d, 0xdd, 0x4f, 0xbe, 0x97, 0xcd, 0x8e, 0x15,
+ 0xb3, 0xc4, 0x1a, 0x17, 0x49, 0x29, 0x32, 0x7c,
+ 0xb3, 0x84, 0xa4, 0x9b, 0xa7, 0x14, 0xb3, 0xc1,
+ 0x5b, 0x3b, 0xfb, 0xa1, 0xe4, 0x23, 0x42, 0x8e,
+ 0x08, 0x1f, 0x53, 0xa2 };
+
+ BUILD_BUG_ON(sizeof(seed) % sizeof(u32));
+
+ memset(&chacha20, 0, sizeof(chacha20));
+ lrng_cc20_init_rfc7539(&chacha20);
+ lrng_selftest_bswap32((u32 *)seed, sizeof(seed) / sizeof(u32));
+
+ /* Generate with zero state */
+ ret = crypto_cb->lrng_drng_generate_helper(&chacha20, outbuf,
+ sizeof(expected_halfblock));
+ if (ret != sizeof(expected_halfblock))
+ goto err;
+ if (memcmp(outbuf, expected_halfblock, sizeof(expected_halfblock)))
+ goto err;
+
+ /* Clear state of DRNG */
+ memset(&chacha20.key.u[0], 0, 48);
+
+ /* Reseed with 2 key blocks */
+ ret = crypto_cb->lrng_drng_seed_helper(&chacha20, seed,
+ sizeof(expected_oneblock));
+ if (ret < 0)
+ goto err;
+ ret = crypto_cb->lrng_drng_generate_helper(&chacha20, outbuf,
+ sizeof(expected_oneblock));
+ if (ret != sizeof(expected_oneblock))
+ goto err;
+ if (memcmp(outbuf, expected_oneblock, sizeof(expected_oneblock)))
+ goto err;
+
+ /* Clear state of DRNG */
+ memset(&chacha20.key.u[0], 0, 48);
+
+ /* Reseed with 1 key block and one byte */
+ ret = crypto_cb->lrng_drng_seed_helper(&chacha20, seed,
+ sizeof(expected_block_nonalinged));
+ if (ret < 0)
+ goto err;
+ ret = crypto_cb->lrng_drng_generate_helper(&chacha20, outbuf,
+ sizeof(expected_block_nonalinged));
+ if (ret != sizeof(expected_block_nonalinged))
+ goto err;
+ if (memcmp(outbuf, expected_block_nonalinged,
+ sizeof(expected_block_nonalinged)))
+ goto err;
+
+ return LRNG_SELFTEST_PASSED;
+
+err:
+ pr_err("LRNG ChaCha20 DRNG self-test FAILED\n");
+ return LRNG_SEFLTEST_ERROR_CHACHA20;
+}
+
+static int lrng_selftest(void)
+{
+ unsigned int ret = lrng_time_process_selftest();
+
+ ret |= lrng_pool_lfsr_selftest();
+ ret |= lrng_chacha20_drng_selftest();
+ ret |= lrng_hash_df_selftest();
+
+ if (ret) {
+ if (IS_ENABLED(CONFIG_LRNG_SELFTEST_PANIC))
+ panic("LRNG self-tests failed: %u\n", ret);
+ } else {
+ pr_info("LRNG self-tests passed\n");
+ }
+
+ lrng_selftest_status = ret;
+
+ if (lrng_selftest_status)
+ return -EFAULT;
+ return 0;
+}
+
+#ifdef CONFIG_SYSFS
+/* Re-perform self-test when any value is written to the sysfs file. */
+static int lrng_selftest_sysfs_set(const char *val,
+ const struct kernel_param *kp)
+{
+ return lrng_selftest();
+}
+
+static const struct kernel_param_ops lrng_selftest_sysfs = {
+ .set = lrng_selftest_sysfs_set,
+ .get = param_get_uint,
+};
+module_param_cb(selftest_status, &lrng_selftest_sysfs, &lrng_selftest_status,
+ 0644);
+#endif /* CONFIG_SYSFS */
+
+static int __init lrng_selftest_init(void)
+{
+ return lrng_selftest();
+}
+
+module_init(lrng_selftest_init);
--
2.26.2
To support the LRNG operation which uses the Jitter RNG separately
from the kernel crypto API, at a time where potentially the regular
memory management is not yet initialized, the Jitter RNG needs to
provide a state whose memory is defined at compile time. As only once
instance will ever be needed by the LRNG, define once static memory
block which is solely to be used by the LRNG.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
crypto/jitterentropy-kcapi.c | 3 +-
crypto/jitterentropy.c | 31 ++++++++++++++++++-
.../crypto/internal}/jitterentropy.h | 3 ++
3 files changed, 34 insertions(+), 3 deletions(-)
rename {crypto => include/crypto/internal}/jitterentropy.h (84%)
diff --git a/crypto/jitterentropy-kcapi.c b/crypto/jitterentropy-kcapi.c
index eb7d1dd506bf..25a192f5984e 100644
--- a/crypto/jitterentropy-kcapi.c
+++ b/crypto/jitterentropy-kcapi.c
@@ -43,8 +43,7 @@
#include <linux/time.h>
#include <linux/crypto.h>
#include <crypto/internal/rng.h>
-
-#include "jitterentropy.h"
+#include <crypto/internal/jitterentropy.h>
/***************************************************************************
* Helper function
diff --git a/crypto/jitterentropy.c b/crypto/jitterentropy.c
index 6e147c43fc18..fa1459f09b01 100644
--- a/crypto/jitterentropy.c
+++ b/crypto/jitterentropy.c
@@ -117,7 +117,7 @@ struct rand_data {
#define JENT_EHEALTH 9 /* Health test failed during initialization */
#define JENT_ERCT 10 /* RCT failed during initialization */
-#include "jitterentropy.h"
+#include <crypto/internal/jitterentropy.h>
/***************************************************************************
* Adaptive Proportion Test
@@ -854,3 +854,32 @@ int jent_entropy_init(void)
return 0;
}
+
+struct rand_data *jent_lrng_entropy_collector(void)
+{
+ static unsigned char lrng_jent_mem[JENT_MEMORY_SIZE];
+ static struct rand_data lrng_jent_state = {
+ .data = 0,
+ .old_data = 0,
+ .prev_time = 0,
+ .last_delta = 0,
+ .last_delta2 = 0,
+ .osr = 1,
+ .mem = lrng_jent_mem,
+ .memlocation = 0,
+ .memblocks = JENT_MEMORY_BLOCKSIZE,
+ .memblocksize = JENT_MEMORY_BLOCKS,
+ .memaccessloops = JENT_MEMORY_ACCESSLOOPS,
+ .rct_count = 0,
+ .apt_observations = 0,
+ .apt_count = 0,
+ .apt_base = 0,
+ .apt_base_set = 0,
+ .health_failure = 0
+ };
+
+ if (jent_entropy_init())
+ return NULL;
+
+ return &lrng_jent_state;
+}
diff --git a/crypto/jitterentropy.h b/include/crypto/internal/jitterentropy.h
similarity index 84%
rename from crypto/jitterentropy.h
rename to include/crypto/internal/jitterentropy.h
index c83fff32d130..6e07d86eac82 100644
--- a/crypto/jitterentropy.h
+++ b/include/crypto/internal/jitterentropy.h
@@ -15,3 +15,6 @@ extern int jent_read_entropy(struct rand_data *ec, unsigned char *data,
extern struct rand_data *jent_entropy_collector_alloc(unsigned int osr,
unsigned int flags);
extern void jent_entropy_collector_free(struct rand_data *entropy_collector);
+
+/* Access to statically allocated Jitter RNG instance */
+extern struct rand_data *jent_lrng_entropy_collector(void);
--
2.26.2
The Jitter RNG fast noise source implemented as part of the kernel
crypto API is queried for 256 bits of entropy at the time the seed
buffer managed by the LRNG is about to be filled.
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
Reviewed-by: Marcelo Henrique Cerri <[email protected]>
Reviewed-by: Roman Drahtmueller <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Tested-by: Neil Horman <[email protected]>
Signed-off-by: Stephan Mueller <[email protected]>
---
drivers/char/lrng/Kconfig | 12 +++++
drivers/char/lrng/Makefile | 1 +
drivers/char/lrng/lrng_jent.c | 88 +++++++++++++++++++++++++++++++++++
3 files changed, 101 insertions(+)
create mode 100644 drivers/char/lrng/lrng_jent.c
diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig
index c89de14d173a..377593fc1985 100644
--- a/drivers/char/lrng/Kconfig
+++ b/drivers/char/lrng/Kconfig
@@ -96,4 +96,16 @@ config LRNG_KCAPI
provided by the selected kernel crypto API RNG.
endif # LRNG_DRNG_SWITCH
+config LRNG_JENT
+ bool "Enable Jitter RNG as LRNG Seed Source"
+ depends on CRYPTO
+ select CRYPTO_JITTERENTROPY
+ help
+ The Linux RNG may use the Jitter RNG as noise source. Enabling
+ this option enables the use of the Jitter RNG. Its default
+ entropy level is 16 bits of entropy per 256 data bits delivered
+ by the Jitter RNG. This entropy level can be changed at boot
+ time or at runtime with the lrng_base.jitterrng configuration
+ variable.
+
endif # LRNG
diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile
index 94b2dfb2dfdb..4f5b6f38f0c4 100644
--- a/drivers/char/lrng/Makefile
+++ b/drivers/char/lrng/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_SYSCTL) += lrng_proc.o
obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o
obj-$(CONFIG_LRNG_DRBG) += lrng_drbg.o
obj-$(CONFIG_LRNG_KCAPI) += lrng_kcapi.o
+obj-$(CONFIG_LRNG_JENT) += lrng_jent.o
diff --git a/drivers/char/lrng/lrng_jent.c b/drivers/char/lrng/lrng_jent.c
new file mode 100644
index 000000000000..225505271fcb
--- /dev/null
+++ b/drivers/char/lrng/lrng_jent.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * LRNG Fast Noise Source: Jitter RNG
+ *
+ * Copyright (C) 2016 - 2020, Stephan Mueller <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <crypto/internal/jitterentropy.h>
+
+#include "lrng_internal.h"
+
+/*
+ * Estimated entropy of data is a 16th of LRNG_DRNG_SECURITY_STRENGTH_BITS.
+ * Albeit a full entropy assessment is provided for the noise source indicating
+ * that it provides high entropy rates and considering that it deactivates
+ * when it detects insufficient hardware, the chosen under estimation of
+ * entropy is considered to be acceptable to all reviewers.
+ */
+static u32 jitterrng = LRNG_DRNG_SECURITY_STRENGTH_BITS>>4;
+module_param(jitterrng, uint, 0644);
+MODULE_PARM_DESC(jitterrng, "Entropy in bits of 256 data bits from Jitter RNG noise source");
+
+/**
+ * lrng_get_jent() - Get Jitter RNG entropy
+ *
+ * @outbuf: buffer to store entropy
+ * @outbuflen: length of buffer
+ *
+ * Return:
+ * * > 0 on success where value provides the added entropy in bits
+ * * 0 if no fast source was available
+ */
+static struct rand_data *lrng_jent_state;
+
+u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen)
+{
+ int ret;
+ u32 ent_bits = jitterrng;
+ unsigned long flags;
+ static DEFINE_SPINLOCK(lrng_jent_lock);
+ static int lrng_jent_initialized = 0;
+
+ spin_lock_irqsave(&lrng_jent_lock, flags);
+
+ if (!ent_bits || (lrng_jent_initialized == -1)) {
+ spin_unlock_irqrestore(&lrng_jent_lock, flags);
+ return 0;
+ }
+
+ if (!lrng_jent_initialized) {
+ lrng_jent_state = jent_lrng_entropy_collector();
+ if (!lrng_jent_state) {
+ jitterrng = 0;
+ lrng_jent_initialized = -1;
+ spin_unlock_irqrestore(&lrng_jent_lock, flags);
+ pr_info("Jitter RNG unusable on current system\n");
+ return 0;
+ }
+ lrng_jent_initialized = 1;
+ pr_debug("Jitter RNG working on current system\n");
+ }
+ ret = jent_read_entropy(lrng_jent_state, outbuf, outbuflen);
+ spin_unlock_irqrestore(&lrng_jent_lock, flags);
+
+ if (ret) {
+ pr_debug("Jitter RNG failed with %d\n", ret);
+ return 0;
+ }
+
+ /* Obtain entropy statement */
+ if (outbuflen != LRNG_DRNG_SECURITY_STRENGTH_BYTES)
+ ent_bits = (ent_bits * outbuflen<<3) /
+ LRNG_DRNG_SECURITY_STRENGTH_BITS;
+ /* Cap entropy to buffer size in bits */
+ ent_bits = min_t(u32, ent_bits, outbuflen<<3);
+ pr_debug("obtained %u bits of entropy from Jitter RNG noise source\n",
+ ent_bits);
+
+ return ent_bits;
+}
+
+u32 lrng_jent_entropylevel(void)
+{
+ return min_t(u32, jitterrng, LRNG_DRNG_SECURITY_STRENGTH_BITS);
+}
--
2.26.2
Hi "Stephan,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on cryptodev/master crypto/master v5.9-rc2 next-20200825]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200825-153914
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git d162219c655c8cf8003128a13840d6c1e183fb80
config: microblaze-randconfig-r023-20200825 (attached as .config)
compiler: microblaze-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=microblaze
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> drivers/char/lrng/lrng_drng.c:381:6: warning: no previous prototype for 'lrng_reset' [-Wmissing-prototypes]
381 | void lrng_reset(void)
| ^~~~~~~~~~
# https://github.com/0day-ci/linux/commit/b5cc1c486b8491ab0a3817a48964bfd4797484c8
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200825-153914
git checkout b5cc1c486b8491ab0a3817a48964bfd4797484c8
vim +/lrng_reset +381 drivers/char/lrng/lrng_drng.c
380
> 381 void lrng_reset(void)
382 {
383 schedule_work(&lrng_reset_work);
384 }
385
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Am Dienstag, 25. August 2020, 13:28:53 CEST schrieb kernel test robot:
Hi,
> All warnings (new ones prefixed by >>):
> >> drivers/char/lrng/lrng_drng.c:381:6: warning: no previous prototype for
> >> 'lrng_reset' [-Wmissing-prototypes]
> 381 | void lrng_reset(void)
>
> | ^~~~~~~~~~
The prototype is covered in an ifdef in lrng_internal.h as it is only needed
for a specific configuration. I have moved the prototype out of that
configuration conditional now.
Thanks.
Ciao
Stephan
Hi "Stephan,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on cryptodev/master crypto/master v5.9-rc1 next-20200821]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200821-140523
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git d162219c655c8cf8003128a13840d6c1e183fb80
:::::: branch date: 2 days ago
:::::: commit date: 2 days ago
config: arm64-randconfig-s031-20200821 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# apt-get install sparse
# sparse version: v0.6.2-191-g10164920-dirty
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=arm64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
sparse warnings: (new ones prefixed by >>)
drivers/char/lrng/lrng_drng.c:381:6: sparse: sparse: symbol 'lrng_reset' was not declared. Should it be static?
--
>> drivers/char/lrng/lrng_chacha20.c:54:47: sparse: sparse: cast to restricted __le32
drivers/char/lrng/lrng_chacha20.c:58:47: sparse: sparse: cast to restricted __le32
--
>> drivers/char/lrng/lrng_interfaces.c:482:16: sparse: sparse: incorrect type in return expression (different base types) @@ expected unsigned int @@ got restricted __poll_t [assigned] [usertype] mask @@
>> drivers/char/lrng/lrng_interfaces.c:482:16: sparse: expected unsigned int
>> drivers/char/lrng/lrng_interfaces.c:482:16: sparse: got restricted __poll_t [assigned] [usertype] mask
>> drivers/char/lrng/lrng_interfaces.c:612:18: sparse: sparse: incorrect type in initializer (different base types) @@ expected restricted __poll_t ( *poll )( ... ) @@ got unsigned int ( * )( ... ) @@
>> drivers/char/lrng/lrng_interfaces.c:612:18: sparse: expected restricted __poll_t ( *poll )( ... )
>> drivers/char/lrng/lrng_interfaces.c:612:18: sparse: got unsigned int ( * )( ... )
# https://github.com/0day-ci/linux/commit/95481f9aadd4408e56c65cd95e47b929224fbc28
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200821-140523
git checkout 95481f9aadd4408e56c65cd95e47b929224fbc28
vim +/lrng_drngs_init_cc20 +81 drivers/char/lrng/lrng_drng.c
95481f9aadd440 Stephan M?ller 2020-08-21 79
95481f9aadd440 Stephan M?ller 2020-08-21 80 /* Initialize the default DRNG during boot */
95481f9aadd440 Stephan M?ller 2020-08-21 @81 static void lrng_drngs_init_cc20(void)
95481f9aadd440 Stephan M?ller 2020-08-21 82 {
95481f9aadd440 Stephan M?ller 2020-08-21 83 unsigned long flags = 0;
95481f9aadd440 Stephan M?ller 2020-08-21 84
95481f9aadd440 Stephan M?ller 2020-08-21 85 if (lrng_get_available())
95481f9aadd440 Stephan M?ller 2020-08-21 86 return;
95481f9aadd440 Stephan M?ller 2020-08-21 87
95481f9aadd440 Stephan M?ller 2020-08-21 88 lrng_drng_lock(&lrng_drng_init, &flags);
95481f9aadd440 Stephan M?ller 2020-08-21 89 if (lrng_get_available()) {
95481f9aadd440 Stephan M?ller 2020-08-21 90 lrng_drng_unlock(&lrng_drng_init, &flags);
95481f9aadd440 Stephan M?ller 2020-08-21 91 return;
95481f9aadd440 Stephan M?ller 2020-08-21 92 }
95481f9aadd440 Stephan M?ller 2020-08-21 93
95481f9aadd440 Stephan M?ller 2020-08-21 94 lrng_drng_reset(&lrng_drng_init);
95481f9aadd440 Stephan M?ller 2020-08-21 95 lrng_cc20_init_state(&chacha20);
95481f9aadd440 Stephan M?ller 2020-08-21 96 lrng_state_init_seed_work();
95481f9aadd440 Stephan M?ller 2020-08-21 97 lrng_drng_unlock(&lrng_drng_init, &flags);
95481f9aadd440 Stephan M?ller 2020-08-21 98
95481f9aadd440 Stephan M?ller 2020-08-21 99 lrng_drng_lock(&lrng_drng_atomic, &flags);
95481f9aadd440 Stephan M?ller 2020-08-21 100 lrng_drng_reset(&lrng_drng_atomic);
95481f9aadd440 Stephan M?ller 2020-08-21 101 /*
95481f9aadd440 Stephan M?ller 2020-08-21 102 * We do not initialize the state of the atomic DRNG as it is identical
95481f9aadd440 Stephan M?ller 2020-08-21 103 * to the DRNG at this point.
95481f9aadd440 Stephan M?ller 2020-08-21 104 */
95481f9aadd440 Stephan M?ller 2020-08-21 105 lrng_drng_unlock(&lrng_drng_atomic, &flags);
95481f9aadd440 Stephan M?ller 2020-08-21 106
95481f9aadd440 Stephan M?ller 2020-08-21 107 lrng_set_available();
95481f9aadd440 Stephan M?ller 2020-08-21 108 }
95481f9aadd440 Stephan M?ller 2020-08-21 109
95481f9aadd440 Stephan M?ller 2020-08-21 110 /************************* Random Number Generation ***************************/
95481f9aadd440 Stephan M?ller 2020-08-21 111
95481f9aadd440 Stephan M?ller 2020-08-21 112 /* Inject a data buffer into the DRNG */
95481f9aadd440 Stephan M?ller 2020-08-21 @113 static void lrng_drng_inject(struct lrng_drng *drng,
95481f9aadd440 Stephan M?ller 2020-08-21 114 const u8 *inbuf, u32 inbuflen)
95481f9aadd440 Stephan M?ller 2020-08-21 115 {
95481f9aadd440 Stephan M?ller 2020-08-21 116 const char *drng_type = unlikely(drng == &lrng_drng_atomic) ?
95481f9aadd440 Stephan M?ller 2020-08-21 117 "atomic" : "regular";
95481f9aadd440 Stephan M?ller 2020-08-21 118 unsigned long flags = 0;
95481f9aadd440 Stephan M?ller 2020-08-21 119
95481f9aadd440 Stephan M?ller 2020-08-21 120 BUILD_BUG_ON(LRNG_DRNG_RESEED_THRESH > INT_MAX);
95481f9aadd440 Stephan M?ller 2020-08-21 121 pr_debug("seeding %s DRNG with %u bytes\n", drng_type, inbuflen);
95481f9aadd440 Stephan M?ller 2020-08-21 122 lrng_drng_lock(drng, &flags);
95481f9aadd440 Stephan M?ller 2020-08-21 123 if (drng->crypto_cb->lrng_drng_seed_helper(drng->drng,
95481f9aadd440 Stephan M?ller 2020-08-21 124 inbuf, inbuflen) < 0) {
95481f9aadd440 Stephan M?ller 2020-08-21 125 pr_warn("seeding of %s DRNG failed\n", drng_type);
95481f9aadd440 Stephan M?ller 2020-08-21 126 atomic_set(&drng->requests, 1);
95481f9aadd440 Stephan M?ller 2020-08-21 127 } else {
95481f9aadd440 Stephan M?ller 2020-08-21 128 pr_debug("%s DRNG stats since last seeding: %lu secs; generate calls: %d\n",
95481f9aadd440 Stephan M?ller 2020-08-21 129 drng_type,
95481f9aadd440 Stephan M?ller 2020-08-21 130 (time_after(jiffies, drng->last_seeded) ?
95481f9aadd440 Stephan M?ller 2020-08-21 131 (jiffies - drng->last_seeded) : 0) / HZ,
95481f9aadd440 Stephan M?ller 2020-08-21 132 (LRNG_DRNG_RESEED_THRESH -
95481f9aadd440 Stephan M?ller 2020-08-21 133 atomic_read(&drng->requests)));
95481f9aadd440 Stephan M?ller 2020-08-21 134 drng->last_seeded = jiffies;
95481f9aadd440 Stephan M?ller 2020-08-21 135 atomic_set(&drng->requests, LRNG_DRNG_RESEED_THRESH);
95481f9aadd440 Stephan M?ller 2020-08-21 136 drng->force_reseed = false;
95481f9aadd440 Stephan M?ller 2020-08-21 137
95481f9aadd440 Stephan M?ller 2020-08-21 138 if (drng->drng == lrng_drng_atomic.drng) {
95481f9aadd440 Stephan M?ller 2020-08-21 139 lrng_drng_atomic.last_seeded = jiffies;
95481f9aadd440 Stephan M?ller 2020-08-21 140 atomic_set(&lrng_drng_atomic.requests,
95481f9aadd440 Stephan M?ller 2020-08-21 141 LRNG_DRNG_RESEED_THRESH);
95481f9aadd440 Stephan M?ller 2020-08-21 142 lrng_drng_atomic.force_reseed = false;
95481f9aadd440 Stephan M?ller 2020-08-21 143 }
95481f9aadd440 Stephan M?ller 2020-08-21 144 }
95481f9aadd440 Stephan M?ller 2020-08-21 145 lrng_drng_unlock(drng, &flags);
95481f9aadd440 Stephan M?ller 2020-08-21 146 }
95481f9aadd440 Stephan M?ller 2020-08-21 147
95481f9aadd440 Stephan M?ller 2020-08-21 148 /*
95481f9aadd440 Stephan M?ller 2020-08-21 149 * Perform the seeding of the DRNG with data from noise source
95481f9aadd440 Stephan M?ller 2020-08-21 150 */
95481f9aadd440 Stephan M?ller 2020-08-21 151 static inline int _lrng_drng_seed(struct lrng_drng *drng)
95481f9aadd440 Stephan M?ller 2020-08-21 152 {
95481f9aadd440 Stephan M?ller 2020-08-21 153 struct entropy_buf seedbuf __aligned(LRNG_KCAPI_ALIGN);
95481f9aadd440 Stephan M?ller 2020-08-21 154 unsigned long flags = 0;
95481f9aadd440 Stephan M?ller 2020-08-21 155 u32 total_entropy_bits;
95481f9aadd440 Stephan M?ller 2020-08-21 156 int ret;
95481f9aadd440 Stephan M?ller 2020-08-21 157
95481f9aadd440 Stephan M?ller 2020-08-21 158 lrng_drng_lock(drng, &flags);
95481f9aadd440 Stephan M?ller 2020-08-21 159 total_entropy_bits = lrng_fill_seed_buffer(drng->crypto_cb, drng->hash,
95481f9aadd440 Stephan M?ller 2020-08-21 160 &seedbuf, 0);
95481f9aadd440 Stephan M?ller 2020-08-21 @161 lrng_drng_unlock(drng, &flags);
95481f9aadd440 Stephan M?ller 2020-08-21 162
95481f9aadd440 Stephan M?ller 2020-08-21 163 /* Allow the seeding operation to be called again */
95481f9aadd440 Stephan M?ller 2020-08-21 164 lrng_pool_unlock();
95481f9aadd440 Stephan M?ller 2020-08-21 165 lrng_init_ops(total_entropy_bits);
95481f9aadd440 Stephan M?ller 2020-08-21 166 ret = total_entropy_bits >> 3;
95481f9aadd440 Stephan M?ller 2020-08-21 167
95481f9aadd440 Stephan M?ller 2020-08-21 168 lrng_drng_inject(drng, (u8 *)&seedbuf, sizeof(seedbuf));
95481f9aadd440 Stephan M?ller 2020-08-21 169 memzero_explicit(&seedbuf, sizeof(seedbuf));
95481f9aadd440 Stephan M?ller 2020-08-21 170
95481f9aadd440 Stephan M?ller 2020-08-21 171 return ret;
95481f9aadd440 Stephan M?ller 2020-08-21 172 }
95481f9aadd440 Stephan M?ller 2020-08-21 173
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Am Mittwoch, 26. August 2020, 16:27:42 CEST schrieb kernel test robot:
Hi,
> >> drivers/char/lrng/lrng_chacha20.c:54:47: sparse: sparse: cast to
> >> restricted __le32
> drivers/char/lrng/lrng_chacha20.c:58:47: sparse: sparse: cast to
> restricted __le32 --
Thanks for the reports. Both, the __poll_t and the __le32 issues are fixed in
v34.
Ciao
Stephan
Hi "Stephan,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on char-misc/char-misc-testing]
[also build test ERROR on cryptodev/master crypto/master v5.9-rc3 next-20200828]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200825-153914
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git d162219c655c8cf8003128a13840d6c1e183fb80
config: riscv-allmodconfig (attached as .config)
compiler: riscv64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=riscv
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
In file included from drivers/char/lrng/lrng_pool.c:18:
>> drivers/char/lrng/lrng_lfsr.h:44:4: error: 'latent_entropy' attribute only applies to functions and variables
44 | atomic_t pool[LRNG_POOL_SIZE] __latent_entropy;
| ^~~~~~~~
--
In file included from drivers/char/lrng/lrng_chacha20.c:17:
>> drivers/char/lrng/lrng_chacha20.h:17:2: error: 'latent_entropy' attribute only applies to functions and variables
17 | } key __latent_entropy;
| ^
drivers/char/lrng/lrng_chacha20.h:19:2: error: 'latent_entropy' attribute only applies to functions and variables
19 | u32 nonce[3] __latent_entropy;
| ^~~
# https://github.com/0day-ci/linux/commit/b5cc1c486b8491ab0a3817a48964bfd4797484c8
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200825-153914
git checkout b5cc1c486b8491ab0a3817a48964bfd4797484c8
vim +/latent_entropy +44 drivers/char/lrng/lrng_lfsr.h
16
17 /*
18 * This is the entropy pool used by the slow noise source. Its size should
19 * be at least as large as LRNG_DRNG_SECURITY_STRENGTH_BITS.
20 *
21 * The pool array is aligned to 8 bytes to comfort the kernel crypto API cipher
22 * implementations of the hash functions used to read the pool: for some
23 * accelerated implementations, we need an alignment to avoid a realignment
24 * which involves memcpy(). The alignment to 8 bytes should satisfy all crypto
25 * implementations.
26 *
27 * LRNG_POOL_SIZE is allowed to be changed only if the taps of the polynomial
28 * used for the LFSR are changed as well. The size must be in powers of 2 due
29 * to the mask handling in lrng_pool_lfsr_u32 which uses AND instead of modulo.
30 */
31 struct lrng_pool {
32 union {
33 struct {
34 /*
35 * hash_df implementation: counter, requested_bits and
36 * pool form a linear buffer that is used in the
37 * hash_df function specified in SP800-90A section
38 * 10.3.1
39 */
40 unsigned char counter;
41 __be32 requested_bits;
42
43 /* Pool */
> 44 atomic_t pool[LRNG_POOL_SIZE] __latent_entropy;
45 /* Ptr into pool for next IRQ word injection */
46 atomic_t pool_ptr;
47 /* rotate for LFSR */
48 atomic_t input_rotate;
49 /* All NUMA DRNGs seeded? */
50 bool all_online_numa_node_seeded;
51 /* IRQ noise source status info */
52 struct lrng_irq_info irq_info;
53 /* Serialize read of entropy pool */
54 spinlock_t lock;
55 };
56 /*
57 * Static SHA-1 implementation in lrng_cc20_hash_buffer
58 * processes data 64-byte-wise. Hence, ensure proper size
59 * of LRNG entropy pool data structure.
60 */
61 u8 hash_input_buf[LRNG_POOL_SIZE_BYTES + 64];
62 };
63 };
64
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Hi "Stephan,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on char-misc/char-misc-testing]
[also build test ERROR on cryptodev/master crypto/master v5.9-rc3 next-20200828]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200825-153914
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git d162219c655c8cf8003128a13840d6c1e183fb80
config: riscv-allmodconfig (attached as .config)
compiler: riscv64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=riscv
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
drivers/char/lrng/lrng_switch.c: In function 'lrng_drng_switch':
>> drivers/char/lrng/lrng_switch.c:20:2: error: variable 'seed' with 'latent_entropy' attribute must not be local
20 | u8 seed[LRNG_DRNG_SECURITY_STRENGTH_BYTES] __latent_entropy;
| ^~
# https://github.com/0day-ci/linux/commit/b4a65336bab63ba2d7b4be76a1acad8eb6b63daf
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Stephan-M-ller/dev-random-a-new-approach-with-full-SP800-90B-compliance/20200825-153914
git checkout b4a65336bab63ba2d7b4be76a1acad8eb6b63daf
vim +20 drivers/char/lrng/lrng_switch.c
13
14 static int lrng_drng_switch(struct lrng_drng *drng_store,
15 const struct lrng_crypto_cb *cb, int node)
16 {
17 const struct lrng_crypto_cb *old_cb;
18 unsigned long flags = 0;
19 int ret;
> 20 u8 seed[LRNG_DRNG_SECURITY_STRENGTH_BYTES] __latent_entropy;
21 void *new_drng = cb->lrng_drng_alloc(LRNG_DRNG_SECURITY_STRENGTH_BYTES);
22 void *old_drng, *new_hash, *old_hash;
23 bool sl = false, reset_drng = !lrng_get_available();
24
25 if (IS_ERR(new_drng)) {
26 pr_warn("could not allocate new DRNG for NUMA node %d (%ld)\n",
27 node, PTR_ERR(new_drng));
28 return PTR_ERR(new_drng);
29 }
30
31 /*
32 * The seed potentially used as MAC key is undefined to add some
33 * variation. Yet, the security of the MAC does not rely on the key
34 * being secret. The key is only there to turn a MAC into a hash.
35 * The intention is to allow the specification of CMAC(AES) as "hash"
36 * to limit the dependency to AES when using the CTR DRBG.
37 */
38 new_hash = cb->lrng_hash_alloc(seed, sizeof(seed));
39 if (IS_ERR(new_hash)) {
40 pr_warn("could not allocate new LRNG pool hash (%ld)\n",
41 PTR_ERR(new_hash));
42 cb->lrng_drng_dealloc(new_drng);
43 return PTR_ERR(new_hash);
44 }
45
46 lrng_drng_lock(drng_store, &flags);
47
48 /*
49 * Pull from existing DRNG to seed new DRNG regardless of seed status
50 * of old DRNG -- the entropy state for the DRNG is left unchanged which
51 * implies that als the new DRNG is reseeded when deemed necessary. This
52 * seeding of the new DRNG shall only ensure that the new DRNG has the
53 * same entropy as the old DRNG.
54 */
55 ret = drng_store->crypto_cb->lrng_drng_generate_helper(
56 drng_store->drng, seed, sizeof(seed));
57 lrng_drng_unlock(drng_store, &flags);
58
59 if (ret < 0) {
60 reset_drng = true;
61 pr_warn("getting random data from DRNG failed for NUMA node %d (%d)\n",
62 node, ret);
63 } else {
64 /* seed new DRNG with data */
65 ret = cb->lrng_drng_seed_helper(new_drng, seed, ret);
66 if (ret < 0) {
67 reset_drng = true;
68 pr_warn("seeding of new DRNG failed for NUMA node %d (%d)\n",
69 node, ret);
70 } else {
71 pr_debug("seeded new DRNG of NUMA node %d instance from old DRNG instance\n",
72 node);
73 }
74 }
75
76 mutex_lock(&drng_store->lock);
77 /*
78 * If we switch the DRNG from the initial ChaCha20 DRNG to something
79 * else, there is a lock transition from spin lock to mutex (see
80 * lrng_drng_is_atomic and how the lock is taken in lrng_drng_lock).
81 * Thus, we need to take both locks during the transition phase.
82 */
83 if (lrng_drng_is_atomic(drng_store)) {
84 spin_lock_irqsave(&drng_store->spin_lock, flags);
85 sl = true;
86 } else {
87 __acquire(&drng_store->spin_lock);
88 }
89
90 if (reset_drng)
91 lrng_drng_reset(drng_store);
92
93 old_drng = drng_store->drng;
94 old_cb = drng_store->crypto_cb;
95 drng_store->drng = new_drng;
96 drng_store->crypto_cb = cb;
97
98 old_hash = drng_store->hash;
99 drng_store->hash = new_hash;
100 pr_info("Entropy pool read-hash allocated for DRNG for NUMA node %d\n",
101 node);
102
103 if (sl)
104 spin_unlock_irqrestore(&drng_store->spin_lock, flags);
105 else
106 __release(&drng_store->spin_lock);
107 mutex_unlock(&drng_store->lock);
108
109 /* ChaCha20 serves as atomic instance left untouched. */
110 if (old_drng != &chacha20) {
111 old_cb->lrng_drng_dealloc(old_drng);
112 old_cb->lrng_hash_dealloc(old_hash);
113 }
114
115 pr_info("DRNG of NUMA node %d switched\n", node);
116
117 return 0;
118 }
119
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Hi,
The following patch set provides a different approach to /dev/random which
is called Linux Random Number Generator (LRNG) to collect entropy within
the Linux kernel.
The following advantages compared to the existing /dev/random
implementation are present:
* Sole use of crypto for data processing:
- exclusive use of a hash operation for conditioning entropy data with
a clear mathematical description as given in [2] section 2.2 -
non-cryptographic operations like LFSR are not used
- accelerated SHA-512 and software SHA-256 hash are available - LRNG works
even if the kernel crypto API is not compiled
- hash operations use NUMA-node-local hash instances to benefit large
parallel systems
- runtime-switchable DRNG and hash implementations which allows
the use of an SP800-90A DRBG or other types of DRNGs
* Performance
- faster by up to 75% in the critical code path of the interrupt handler
depending on data collection size configurable at kernel compile time -
the default is about equal in performance with existing /dev/random
- configurable data collection sizes to accommodate small environments and
big environments
- entropy collection using an almost never contended lock to benefit
large parallel systems - worst case rate of contention is the number
of DRNG reseeds, usually the number of potential contentions per 5
minutes is equal to number of NUMA nodes.
- ChaCha20 DRNG is significantly faster as implemented in random.c
- faster entropy collection during boot time to reach fully seeded level,
including on virtual systems or systems with SSDs
* Testing
- heuristic entropy estimation is based on analysis following SP800-90B
and not on coincidental underestimation of entropy
- power-on self tests for critical deterministic components
(ChaCha20 DRNG, hash, and entropy collection logic) not already
covered by power-up tests of the kernel crypto API
- availability of test interfaces for all operational stages of the LRNG
including boot-time raw entropy event data sampling
- fully testable ChaCha20 DRNG - see [3]
* Entropy collection
- The LRNG is fully compliant to SP800-90B requirements and is shipped with
a full SP800-90B assessment and all required test tools in [1]. The
existing /dev/random implementation on the other hand has architectural
limitations which does not easily allow to bring the implementation in
compliance with SP800-90B. The existing /dev/random is not easily made
compliant with SP800-90B as outlined in [2] section 4.5.
- full entropy assessment and description provided with [2], specifically
section 3.2.6
- guarantee that entropy events are not credited with entropy twice
(the existing /dev/random implementation credits HID/disk and interrupt
events with entropy which are a derivative of each other) and
guarantee that entropy data is not reused for two different use cases
(as done in the existing /dev/random implementation when injecting a
part of fast_pool into the net_rand_state)
The LRNG patch set allows a user to select use of the existing /dev/random
or the LRNG during compile time. As the LRNG provides API and ABI compatible
interfaces to the existing /dev/random implementation, the user can freely
chose the RNG implementation without affecting kernel or user space
operations.
For users that are not interested in SP800-90B, the entire code for the
compliance as well as test interfaces can be deselected at compile time.
The design and implementation is driven by a set of goals described in [2]
that the LRNG completely implements. Furthermore, [2] includes the full
assessment of the SP800-90B compliance as well as a comparison with RNG
design suggestions of SP800-90C, and AIS20/31.
The LRNG provides a complete separation of the noise source maintenance
and the collection of entropy into per-CPU entropy pools from the
post-processing using a pseudo-random number generator. Different
DRNGs are supported, including:
* Built-in ChaCha20 DRNG which has no dependency to other kernel
frameworks.
* SP800-90A DRBG using the kernel crypto API including its accelerated
raw cipher implementations. This implies that the output of /dev/random,
getrandom(2), /dev/urandom or get_random_bytes is fully compliant to
SP800-90A.
* Arbitrary DRNGs registered with the kernel crypto API
Booting the patch with the kernel command line option
"dyndbg=file drivers/char/lrng/* +p" generates logs indicating the
operation of the LRNG. Each log is pre-pended with "lrng".
The LRNG has a flexible design by allowing an easy replacement of the
deterministic random number generator component as well as hash
component.
Full SP800-90B testing is performed on the following systems - details
are given in [2] appendix C:
* x86 KVM virtualized guest 32 and 64 bit systems
* x86 bare metal
* older and newer ARMv7 system
* ARM64
* POWER7 LE and POWER 8 BE
* IBM Z System mainframe
* old MIPS embedded device
* testing with GCC and Clang
[1] https://www.chronox.de/lrng.html - If the patch is accepted, I would
be volunteering to convert the documentation into RST format and
contribute it to the Linux kernel documentation directory.
[2] https://www.chronox.de/lrng/doc/lrng.pdf
[3] https://www.chronox.de/chacha20_drng.html
Changes (compared to the previous patch set):
* replace hash_df operation with simple hash to make code leaner without
affecting entropy statements
* replace central LFSR with per-CPU entropy pools which implies that
LRNG only uses a hash for conditioning - this makes data processing
much cleaner (see [2] section 2.2) entropy assessment significantly
easier (see [2] section 3.2.6)
* add aux_pool to process data received from user space and
add_hwgenerator_randomness with a cryptographic hash compliant to
SP800-90B section 3.1.6 to allow data from those sources and stay
SP800-90B compliant
* remove duplicated code - add lrng_kcapi_hash.c to consolidate hash
handling code from lrng_drbg.c and lrng_kcapi.c
* ensure that the NUMA pool allocation also allocates the hash instance
as a precaution in case the DRNG switching code is executed before
the NUMA allocation
* Make invocation of SHA-1 compliant to FIPS 180-4
* Addition of test interface for interrupt registers noise data -
with that interface, all data potentially delivering entropy can be
sampled.
* Addition of ACVT interface to validate correct invocation of SHA by
LRNG (for test definition, see https://github.com/usnistgov/ACVP) -
interface was used for successful testing of the SHA-256 and SHA-1
handling of the LRNG.
* remove superfluous backslash from Makefile reported by
Andy Lavr <[email protected]>
* move prototype of lrng_reset() to a spot in lrng_internal.h that is
compiled unconditional as requested by kernel test robot
<[email protected]>
* correctly advance *ppos in DebugFS read function for testing interfaces
preventing successive read operations
* fix __latent_entropy usage as reported by kernel test robot
<[email protected]>
* use compxch_release / smp_load_acquire to set NUMA pool as suggested
by Eric Biggers
CC: "Eric W. Biederman" <[email protected]>
CC: "Alexander E. Patrakov" <[email protected]>
CC: "Ahmed S. Darwish" <[email protected]>
CC: "Theodore Y. Ts'o" <[email protected]>
CC: Willy Tarreau <[email protected]>
CC: Matthew Garrett <[email protected]>
CC: Vito Caputo <[email protected]>
CC: Andreas Dilger <[email protected]>
CC: Jan Kara <[email protected]>
CC: Ray Strode <[email protected]>
CC: William Jon McCann <[email protected]>
CC: zhangjs <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Florian Weimer <[email protected]>
CC: Lennart Poettering <[email protected]>
CC: Nicolai Stange <[email protected]>
CC: Eric Biggers <[email protected]>
Tested-by: Roman Drahtm?ller <[email protected]>
Tested-by: Marcelo Henrique Cerri <[email protected]>
Stephan Mueller (13):
Linux Random Number Generator
LRNG - allocate one DRNG instance per NUMA node
LRNG - sysctls and /proc interface
LRNG - add switchable DRNG support
LRNG - add common generic hash support
crypto: DRBG - externalize DRBG functions for LRNG
LRNG - add SP800-90A DRBG extension
LRNG - add kernel crypto API PRNG extension
crypto: provide access to a static Jitter RNG state
LRNG - add Jitter RNG fast noise source
LRNG - add SP800-90B compliant health tests
LRNG - add interface for gathering of raw entropy
LRNG - add power-on and runtime self-tests
MAINTAINERS | 7 +
crypto/drbg.c | 16 +-
crypto/jitterentropy-kcapi.c | 3 +-
crypto/jitterentropy.c | 31 +-
drivers/char/Kconfig | 2 +
drivers/char/Makefile | 9 +-
drivers/char/lrng/Kconfig | 353 +++++++++
drivers/char/lrng/Makefile | 20 +
drivers/char/lrng/lrng_archrandom.c | 93 +++
drivers/char/lrng/lrng_aux.c | 136 ++++
drivers/char/lrng/lrng_chacha20.c | 352 +++++++++
drivers/char/lrng/lrng_chacha20.h | 29 +
drivers/char/lrng/lrng_drbg.c | 197 +++++
drivers/char/lrng/lrng_drng.c | 406 +++++++++++
drivers/char/lrng/lrng_health.c | 407 +++++++++++
drivers/char/lrng/lrng_interfaces.c | 649 +++++++++++++++++
drivers/char/lrng/lrng_internal.h | 426 +++++++++++
drivers/char/lrng/lrng_jent.c | 88 +++
drivers/char/lrng/lrng_kcapi.c | 228 ++++++
drivers/char/lrng/lrng_kcapi_hash.c | 97 +++
drivers/char/lrng/lrng_kcapi_hash.h | 19 +
drivers/char/lrng/lrng_numa.c | 108 +++
drivers/char/lrng/lrng_pool.c | 478 ++++++++++++
drivers/char/lrng/lrng_proc.c | 181 +++++
drivers/char/lrng/lrng_selftest.c | 344 +++++++++
drivers/char/lrng/lrng_sw_noise.c | 461 ++++++++++++
drivers/char/lrng/lrng_sw_noise.h | 56 ++
drivers/char/lrng/lrng_switch.c | 203 ++++++
drivers/char/lrng/lrng_testing.c | 687 ++++++++++++++++++
include/crypto/drbg.h | 7 +
.../crypto/internal}/jitterentropy.h | 3 +
include/linux/lrng.h | 79 ++
32 files changed, 6165 insertions(+), 10 deletions(-)
create mode 100644 drivers/char/lrng/Kconfig
create mode 100644 drivers/char/lrng/Makefile
create mode 100644 drivers/char/lrng/lrng_archrandom.c
create mode 100644 drivers/char/lrng/lrng_aux.c
create mode 100644 drivers/char/lrng/lrng_chacha20.c
create mode 100644 drivers/char/lrng/lrng_chacha20.h
create mode 100644 drivers/char/lrng/lrng_drbg.c
create mode 100644 drivers/char/lrng/lrng_drng.c
create mode 100644 drivers/char/lrng/lrng_health.c
create mode 100644 drivers/char/lrng/lrng_interfaces.c
create mode 100644 drivers/char/lrng/lrng_internal.h
create mode 100644 drivers/char/lrng/lrng_jent.c
create mode 100644 drivers/char/lrng/lrng_kcapi.c
create mode 100644 drivers/char/lrng/lrng_kcapi_hash.c
create mode 100644 drivers/char/lrng/lrng_kcapi_hash.h
create mode 100644 drivers/char/lrng/lrng_numa.c
create mode 100644 drivers/char/lrng/lrng_pool.c
create mode 100644 drivers/char/lrng/lrng_proc.c
create mode 100644 drivers/char/lrng/lrng_selftest.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.c
create mode 100644 drivers/char/lrng/lrng_sw_noise.h
create mode 100644 drivers/char/lrng/lrng_switch.c
create mode 100644 drivers/char/lrng/lrng_testing.c
rename {crypto => include/crypto/internal}/jitterentropy.h (84%)
create mode 100644 include/linux/lrng.h
--
2.26.2