Series applies on top of
https://lore.kernel.org/linux-integrity/[email protected]/T/#u
v2 -> v3:
- Split off first Kconfig preparation patch. It fixes a regression,
so sent that out, so it can be applied separately (Sumit)
- Split off second key import patch. I'll send that out separately
as it's a development aid and not required within the CAAM series
- add MAINTAINERS entry
v1 -> v2:
- Added new commit to make trusted key Kconfig option independent
of TPM and added new Kconfig file for trusted keys
- Add new commit for importing existing key material
- Allow users to force use of kernel RNG (Jarkko)
- Enforce maximum keymod size (Horia)
- Use append_seq_(in|out)_ptr_intlen instead of append_seq_(in|out)_ptr
(Horia)
- Make blobifier handle private to CAAM glue code file (Horia)
- Extend trusted keys documentation for CAAM
- Rebased and updated original cover letter:
The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
built into many newer i.MX and QorIQ SoCs by NXP.
Its blob mechanism can AES encrypt/decrypt user data using a unique
never-disclosed device-specific key.
There has been multiple discussions on how to represent this within the kernel:
The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
built into many newer i.MX and QorIQ SoCs by NXP.
Its blob mechanism can AES encrypt/decrypt user data using a unique
never-disclosed device-specific key. There has been multiple
discussions on how to represent this within the kernel:
- [RFC] crypto: caam - add red blobifier
Steffen implemented[1] a PoC sysfs driver to start a discussion on how to
best integrate the blob mechanism.
Mimi suggested that it could be used to implement trusted keys.
Trusted keys back then were a TPM-only feature.
- security/keys/secure_key: Adds the secure key support based on CAAM.
Udit added[2] a new "secure" key type with the CAAM as backend. The key
material stays within the kernel only.
Mimi and James agreed that this needs a generic interface, not specific
to CAAM. Mimi suggested trusted keys. Jan noted that this could serve as
basis for TEE-backed keys.
- [RFC] drivers: crypto: caam: key: Add caam_tk key type
Franck added[3] a new "caam_tk" key type based on Udit's work. This time
it uses CAAM "black blobs" instead of "red blobs", so key material stays
within the CAAM and isn't exposed to kernel in plaintext.
James voiced the opinion that there should be just one user-facing generic
wrap/unwrap key type with multiple possible handlers.
David suggested trusted keys.
- Introduce TEE based Trusted Keys support
Sumit reworked[4] trusted keys to support multiple possible backends with
one chosen at boot time and added a new TEE backend along with TPM.
This now sits in Jarkko's master branch to be sent out for v5.13
This patch series builds on top of Sumit's rework to have the CAAM as yet another
trusted key backend.
The CAAM bits are based on Steffen's initial patch from 2015. His work had been
used in the field for some years now, so I preferred not to deviate too much from it.
This series has been tested with dmcrypt[5] on an i.MX6DL.
Looking forward to your feedback.
Cheers,
Ahmad
[1]: https://lore.kernel.org/linux-crypto/[email protected]/
[2]: https://lore.kernel.org/linux-integrity/[email protected]/
[3]: https://lore.kernel.org/lkml/[email protected]/
[4]: https://lore.kernel.org/lkml/[email protected]/
[5]: https://lore.kernel.org/linux-integrity/[email protected]/
---
To: Jarkko Sakkinen <[email protected]>
To: "Horia Geantă" <[email protected]>
To: Mimi Zohar <[email protected]>
To: Aymen Sghaier <[email protected]>
To: Herbert Xu <[email protected]>
To: "David S. Miller" <[email protected]>
To: James Bottomley <[email protected]>
Cc: David Howells <[email protected]>
Cc: James Morris <[email protected]>
Cc: "Serge E. Hallyn" <[email protected]>
Cc: Steffen Trumtrar <[email protected]>
Cc: Udit Agarwal <[email protected]>
Cc: Jan Luebbe <[email protected]>
Cc: David Gstir <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Franck LENORMAND <[email protected]>
Cc: Sumit Garg <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Ahmad Fatoum (4):
KEYS: trusted: allow users to use kernel RNG for key material
KEYS: trusted: allow trust sources to use kernel RNG for key material
crypto: caam - add in-kernel interface for blob generator
KEYS: trusted: Introduce support for NXP CAAM-based trusted keys
Documentation/admin-guide/kernel-parameters.txt | 8 +-
Documentation/security/keys/trusted-encrypted.rst | 60 +++-
MAINTAINERS | 9 +-
drivers/crypto/caam/Kconfig | 3 +-
drivers/crypto/caam/Makefile | 1 +-
drivers/crypto/caam/blob_gen.c | 230 +++++++++++++++-
include/keys/trusted-type.h | 2 +-
include/keys/trusted_caam.h | 11 +-
include/soc/fsl/caam-blob.h | 56 ++++-
security/keys/trusted-keys/Kconfig | 11 +-
security/keys/trusted-keys/Makefile | 2 +-
security/keys/trusted-keys/trusted_caam.c | 74 +++++-
security/keys/trusted-keys/trusted_core.c | 23 +-
13 files changed, 477 insertions(+), 13 deletions(-)
create mode 100644 drivers/crypto/caam/blob_gen.c
create mode 100644 include/keys/trusted_caam.h
create mode 100644 include/soc/fsl/caam-blob.h
create mode 100644 security/keys/trusted-keys/trusted_caam.c
base-commit: 97408d81ed533b953326c580ff2c3f1948b3fcee
--
git-series 0.9.1
The two existing trusted key sources don't make use of the kernel RNG,
but instead let the hardware doing the sealing/unsealing also
generate the random key material. However, Users may want to place
less trust into the quality of the trust source's random number
generator and instead use the kernel entropy pool, which can be
seeded from multiple entropy sources.
Make this possible by adding a new trusted.kernel_rng parameter,
that will force use of the kernel RNG. In its absence, it's up
to the trust source to decide, which random numbers to use,
maintaining the existing behavior.
Suggested-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Ahmad Fatoum <[email protected]>
---
To: James Bottomley <[email protected]>
To: Jarkko Sakkinen <[email protected]>
To: Mimi Zohar <[email protected]>
To: David Howells <[email protected]>
Cc: James Morris <[email protected]>
Cc: "Serge E. Hallyn" <[email protected]>
Cc: "Horia Geantă" <[email protected]>
Cc: Aymen Sghaier <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Udit Agarwal <[email protected]>
Cc: Jan Luebbe <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: David Gstir <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Franck LENORMAND <[email protected]>
Cc: Sumit Garg <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
Documentation/admin-guide/kernel-parameters.txt | 7 ++++++-
Documentation/security/keys/trusted-encrypted.rst | 20 +++++++++-------
security/keys/trusted-keys/trusted_core.c | 17 +++++++++++++-
3 files changed, 35 insertions(+), 9 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index bdb22006f713..0267ead88902 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5734,6 +5734,13 @@
first trust source as a backend which is initialized
successfully during iteration.
+ trusted.kernel_rng = [KEYS]
+ Format: <bool>
+ When set to true (1), the kernel random number pool
+ is used to generate key material for trusted keys.
+ The default is to leave the RNG's choice to each
+ individual trust source.
+
tsc= Disable clocksource stability checks for TSC.
Format: <string>
[x86] reliable: mark tsc clocksource as reliable, this
diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
index 80d5a5af62a1..1d4b4b8f12f0 100644
--- a/Documentation/security/keys/trusted-encrypted.rst
+++ b/Documentation/security/keys/trusted-encrypted.rst
@@ -87,22 +87,26 @@ Key Generation
Trusted Keys
------------
-New keys are created from random numbers generated in the trust source. They
-are encrypted/decrypted using a child key in the storage key hierarchy.
-Encryption and decryption of the child key must be protected by a strong
-access control policy within the trust source.
+New keys are created from random numbers. They are encrypted/decrypted using
+a child key in the storage key hierarchy. Encryption and decryption of the
+child key must be protected by a strong access control policy within the
+trust source. The random number generator in use differs according to the
+selected trust source:
- * TPM (hardware device) based RNG
+ * TPM: hardware device based RNG
- Strength of random numbers may vary from one device manufacturer to
- another.
+ Keys are generated within the TPM. Strength of random numbers may vary
+ from one device manufacturer to another.
- * TEE (OP-TEE based on Arm TrustZone) based RNG
+ * TEE: OP-TEE based on Arm TrustZone based RNG
RNG is customizable as per platform needs. It can either be direct output
from platform specific hardware RNG or a software based Fortuna CSPRNG
which can be seeded via multiple entropy sources.
+Optionally, users may specify ``trusted.kernel_rng=1`` on the kernel
+command-line to override the used RNG with the kernel's random number pool.
+
Encrypted Keys
--------------
diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
index 8cab69e5d0da..569af9af8df0 100644
--- a/security/keys/trusted-keys/trusted_core.c
+++ b/security/keys/trusted-keys/trusted_core.c
@@ -16,12 +16,17 @@
#include <linux/key-type.h>
#include <linux/module.h>
#include <linux/parser.h>
+#include <linux/random.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#include <linux/static_call.h>
#include <linux/string.h>
#include <linux/uaccess.h>
+static bool trusted_kernel_rng;
+module_param_named(kernel_rng, trusted_kernel_rng, bool, 0);
+MODULE_PARM_DESC(kernel_rng, "Generate key material from kernel RNG");
+
static char *trusted_key_source;
module_param_named(source, trusted_key_source, charp, 0);
MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)");
@@ -312,8 +317,14 @@ struct key_type key_type_trusted = {
};
EXPORT_SYMBOL_GPL(key_type_trusted);
+static int kernel_get_random(unsigned char *key, size_t key_len)
+{
+ return get_random_bytes_wait(key, key_len) ?: key_len;
+}
+
static int __init init_trusted(void)
{
+ int (*get_random)(unsigned char *key, size_t key_len);
int i, ret = 0;
for (i = 0; i < ARRAY_SIZE(trusted_key_sources); i++) {
@@ -322,6 +333,10 @@ static int __init init_trusted(void)
strlen(trusted_key_sources[i].name)))
continue;
+ get_random = trusted_key_sources[i].ops->get_random;
+ if (trusted_kernel_rng)
+ get_random = kernel_get_random;
+
static_call_update(trusted_key_init,
trusted_key_sources[i].ops->init);
static_call_update(trusted_key_seal,
@@ -329,7 +344,7 @@ static int __init init_trusted(void)
static_call_update(trusted_key_unseal,
trusted_key_sources[i].ops->unseal);
static_call_update(trusted_key_get_random,
- trusted_key_sources[i].ops->get_random);
+ get_random);
static_call_update(trusted_key_exit,
trusted_key_sources[i].ops->exit);
migratable = trusted_key_sources[i].ops->migratable;
--
git-series 0.9.1
The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
built into many newer i.MX and QorIQ SoCs by NXP.
The CAAM does crypto acceleration, hardware number generation and
has a blob mechanism for encapsulation/decapsulation of sensitive material.
This blob mechanism depends on a device specific random 256-bit One Time
Programmable Master Key that is fused in each SoC at manufacturing
time. This key is unreadable and can only be used by the CAAM for AES
encryption/decryption of user data.
This makes it a suitable backend (source) for kernel trusted keys.
Previous commits generalized trusted keys to support multiple backends
and added an API to access the CAAM blob mechanism. Based on these,
provide the necessary glue to use the CAAM for trusted keys.
Signed-off-by: Ahmad Fatoum <[email protected]>
---
To: Jonathan Corbet <[email protected]>
To: David Howells <[email protected]>
To: Jarkko Sakkinen <[email protected]>
To: James Bottomley <[email protected]>
To: Mimi Zohar <[email protected]>
Cc: James Morris <[email protected]>
Cc: "Serge E. Hallyn" <[email protected]>
Cc: "Horia Geantă" <[email protected]>
Cc: Aymen Sghaier <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Udit Agarwal <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Jan Luebbe <[email protected]>
Cc: David Gstir <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Franck LENORMAND <[email protected]>
Cc: Sumit Garg <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
Documentation/admin-guide/kernel-parameters.txt | 1 +-
Documentation/security/keys/trusted-encrypted.rst | 42 ++++++++-
MAINTAINERS | 9 ++-
include/keys/trusted_caam.h | 11 ++-
security/keys/trusted-keys/Kconfig | 11 +-
security/keys/trusted-keys/Makefile | 2 +-
security/keys/trusted-keys/trusted_caam.c | 74 ++++++++++++++++-
security/keys/trusted-keys/trusted_core.c | 6 +-
8 files changed, 152 insertions(+), 4 deletions(-)
create mode 100644 include/keys/trusted_caam.h
create mode 100644 security/keys/trusted-keys/trusted_caam.c
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 0267ead88902..43010cb27f17 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5729,6 +5729,7 @@
sources:
- "tpm"
- "tee"
+ - "caam"
If not specified then it defaults to iterating through
the trust source list starting with TPM and assigns the
first trust source as a backend which is initialized
diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
index 1d4b4b8f12f0..ad66573ca6fd 100644
--- a/Documentation/security/keys/trusted-encrypted.rst
+++ b/Documentation/security/keys/trusted-encrypted.rst
@@ -35,6 +35,13 @@ safe.
Rooted to Hardware Unique Key (HUK) which is generally burnt in on-chip
fuses and is accessible to TEE only.
+ (3) CAAM (Cryptographic Acceleration and Assurance Module: IP on NXP SoCs)
+
+ When High Assurance Boot (HAB) is enabled and the CAAM is in secure
+ mode, trust is rooted to the OTPMK, a never-disclosed 256-bit key
+ randomly generated and fused into each SoC at manufacturing time.
+ Otherwise, a common fixed test key is used instead.
+
* Execution isolation
(1) TPM
@@ -46,6 +53,10 @@ safe.
Customizable set of operations running in isolated execution
environment verified via Secure/Trusted boot process.
+ (3) CAAM
+
+ Fixed set of operations running in isolated execution environment.
+
* Optional binding to platform integrity state
(1) TPM
@@ -63,6 +74,11 @@ safe.
Relies on Secure/Trusted boot process for platform integrity. It can
be extended with TEE based measured boot process.
+ (3) CAAM
+
+ Relies on the High Assurance Boot (HAB) mechanism of NXP SoCs
+ for platform integrity.
+
* Interfaces and APIs
(1) TPM
@@ -74,10 +90,13 @@ safe.
TEEs have well-documented, standardized client interface and APIs. For
more details refer to ``Documentation/staging/tee.rst``.
+ (3) CAAM
+
+ Interface is specific to silicon vendor.
* Threat model
- The strength and appropriateness of a particular TPM or TEE for a given
+ The strength and appropriateness of a particular trust source for a given
purpose must be assessed when using them to protect security-relevant data.
@@ -104,8 +123,14 @@ selected trust source:
from platform specific hardware RNG or a software based Fortuna CSPRNG
which can be seeded via multiple entropy sources.
+ * CAAM: Kernel RNG
+
+ The normal kernel random number generator is used. To seed it from the
+ CAAM HWRNG, enable CRYPTO_DEV_FSL_CAAM_RNG_API and ensure the device
+ can be probed.
+
Optionally, users may specify ``trusted.kernel_rng=1`` on the kernel
-command-line to override the used RNG with the kernel's random number pool.
+command-line to force use of the kernel's random number pool.
Encrypted Keys
--------------
@@ -192,6 +217,19 @@ Usage::
specific to TEE device implementation. The key length for new keys is always
in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits).
+Trusted Keys usage: CAAM
+------------------------
+
+Usage::
+
+ keyctl add trusted name "new keylen" ring
+ keyctl add trusted name "load hex_blob" ring
+ keyctl print keyid
+
+"keyctl print" returns an ASCII hex copy of the sealed key, which is in format
+specific to CAAM device implementation. The key length for new keys is always
+in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits).
+
Encrypted Keys usage
--------------------
diff --git a/MAINTAINERS b/MAINTAINERS
index 6c8be735cc91..aa654e69075d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10265,6 +10265,15 @@ S: Supported
F: include/keys/trusted_tee.h
F: security/keys/trusted-keys/trusted_tee.c
+KEYS-TRUSTED-CAAM
+M: Ahmad Fatoum <[email protected]>
+R: Pengutronix Kernel Team <[email protected]>
+L: [email protected]
+L: [email protected]
+S: Supported
+F: include/keys/trusted_caam.h
+F: security/keys/trusted-keys/trusted_caam.c
+
KEYS/KEYRINGS
M: David Howells <[email protected]>
M: Jarkko Sakkinen <[email protected]>
diff --git a/include/keys/trusted_caam.h b/include/keys/trusted_caam.h
new file mode 100644
index 000000000000..2fba0996b0b0
--- /dev/null
+++ b/include/keys/trusted_caam.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2021 Pengutronix, Ahmad Fatoum <[email protected]>
+ */
+
+#ifndef __CAAM_TRUSTED_KEY_H
+#define __CAAM_TRUSTED_KEY_H
+
+extern struct trusted_key_ops caam_trusted_key_ops;
+
+#endif
diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig
index c163cfeedff6..fac80117ef46 100644
--- a/security/keys/trusted-keys/Kconfig
+++ b/security/keys/trusted-keys/Kconfig
@@ -24,6 +24,15 @@ config TRUSTED_KEYS_TEE
Enable use of the Trusted Execution Environment (TEE) as trusted
key backend.
-if !TRUSTED_KEYS_TPM && !TRUSTED_KEYS_TEE
+config TRUSTED_KEYS_CAAM
+ bool "CAAM-based trusted keys"
+ depends on CRYPTO_DEV_FSL_CAAM_JR >= TRUSTED_KEYS
+ select CRYPTO_DEV_FSL_CAAM_BLOB_GEN
+ default y
+ help
+ Enable use of NXP's Cryptographic Accelerator and Assurance Module
+ (CAAM) as trusted key backend.
+
+if !TRUSTED_KEYS_TPM && !TRUSTED_KEYS_TEE && !TRUSTED_KEYS_CAAM
comment "No trust source selected!"
endif
diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile
index 2e2371eae4d5..735aa0bc08ef 100644
--- a/security/keys/trusted-keys/Makefile
+++ b/security/keys/trusted-keys/Makefile
@@ -12,3 +12,5 @@ trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm2.o
trusted-$(CONFIG_TRUSTED_KEYS_TPM) += tpm2key.asn1.o
trusted-$(CONFIG_TRUSTED_KEYS_TEE) += trusted_tee.o
+
+trusted-$(CONFIG_TRUSTED_KEYS_CAAM) += trusted_caam.o
diff --git a/security/keys/trusted-keys/trusted_caam.c b/security/keys/trusted-keys/trusted_caam.c
new file mode 100644
index 000000000000..01adfd18adda
--- /dev/null
+++ b/security/keys/trusted-keys/trusted_caam.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 Pengutronix, Ahmad Fatoum <[email protected]>
+ */
+
+#include <keys/trusted_caam.h>
+#include <keys/trusted-type.h>
+#include <linux/build_bug.h>
+#include <linux/key-type.h>
+#include <soc/fsl/caam-blob.h>
+
+static struct caam_blob_priv *blobifier;
+
+#define KEYMOD "kernel:trusted"
+
+static_assert(MAX_KEY_SIZE + CAAM_BLOB_OVERHEAD <= CAAM_BLOB_MAX_LEN);
+static_assert(MAX_BLOB_SIZE <= CAAM_BLOB_MAX_LEN);
+
+static int trusted_caam_seal(struct trusted_key_payload *p, char *datablob)
+{
+ int length = p->key_len + CAAM_BLOB_OVERHEAD;
+ int ret;
+
+ ret = caam_encap_blob(blobifier, KEYMOD, p->key, p->blob, length);
+ if (ret)
+ return ret;
+
+ p->blob_len = length;
+ return 0;
+}
+
+static int trusted_caam_unseal(struct trusted_key_payload *p, char *datablob)
+{
+ int length = p->blob_len;
+ int ret;
+
+ ret = caam_decap_blob(blobifier, KEYMOD, p->blob, p->key, length);
+ if (ret)
+ return ret;
+
+ p->key_len = length - CAAM_BLOB_OVERHEAD;
+ return 0;
+}
+
+static int trusted_caam_init(void)
+{
+ int ret;
+
+ blobifier = caam_blob_gen_init();
+ if (IS_ERR(blobifier)) {
+ pr_err("Job Ring Device allocation for transform failed\n");
+ return PTR_ERR(blobifier);
+ }
+
+ ret = register_key_type(&key_type_trusted);
+ if (ret)
+ caam_blob_gen_exit(blobifier);
+
+ return ret;
+}
+
+static void trusted_caam_exit(void)
+{
+ unregister_key_type(&key_type_trusted);
+ caam_blob_gen_exit(blobifier);
+}
+
+struct trusted_key_ops caam_trusted_key_ops = {
+ .migratable = 0, /* non-migratable */
+ .init = trusted_caam_init,
+ .seal = trusted_caam_seal,
+ .unseal = trusted_caam_unseal,
+ .exit = trusted_caam_exit,
+};
diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
index d2b7626cde8b..305e44651180 100644
--- a/security/keys/trusted-keys/trusted_core.c
+++ b/security/keys/trusted-keys/trusted_core.c
@@ -9,6 +9,7 @@
#include <keys/user-type.h>
#include <keys/trusted-type.h>
#include <keys/trusted_tee.h>
+#include <keys/trusted_caam.h>
#include <keys/trusted_tpm.h>
#include <linux/capability.h>
#include <linux/err.h>
@@ -29,7 +30,7 @@ MODULE_PARM_DESC(kernel_rng, "Generate key material from kernel RNG");
static char *trusted_key_source;
module_param_named(source, trusted_key_source, charp, 0);
-MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)");
+MODULE_PARM_DESC(source, "Select trusted keys source (tpm, tee or caam)");
static const struct trusted_key_source trusted_key_sources[] = {
#if defined(CONFIG_TRUSTED_KEYS_TPM)
@@ -38,6 +39,9 @@ static const struct trusted_key_source trusted_key_sources[] = {
#if defined(CONFIG_TRUSTED_KEYS_TEE)
{ "tee", &trusted_key_tee_ops },
#endif
+#if defined(CONFIG_TRUSTED_KEYS_CAAM)
+ { "caam", &caam_trusted_key_ops },
+#endif
};
DEFINE_STATIC_CALL_NULL(trusted_key_init, *trusted_key_sources[0].ops->init);
--
git-series 0.9.1
The two existing trusted key sources don't make use of the kernel RNG,
but instead let the hardware that does the sealing/unsealing also
generate the random key material. While a previous change offers users
the choice to use the kernel RNG instead for both, new trust sources
may want to unconditionally use the kernel RNG for generating key
material, like it's done elsewhere in the kernel.
This is especially prudent for hardware that has proven-in-production
HWRNG drivers implemented, as otherwise code would have to be duplicated
only to arrive at a possibly worse result.
Make this possible by turning struct trusted_key_ops::get_random
into an optional member. If a driver leaves it NULL, kernel RNG
will be used instead.
Signed-off-by: Ahmad Fatoum <[email protected]>
---
To: James Bottomley <[email protected]>
To: Jarkko Sakkinen <[email protected]>
To: Mimi Zohar <[email protected]>
To: David Howells <[email protected]>
Cc: James Morris <[email protected]>
Cc: "Serge E. Hallyn" <[email protected]>
Cc: "Horia Geantă" <[email protected]>
Cc: Aymen Sghaier <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Udit Agarwal <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Jan Luebbe <[email protected]>
Cc: David Gstir <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Franck LENORMAND <[email protected]>
Cc: Sumit Garg <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
include/keys/trusted-type.h | 2 +-
security/keys/trusted-keys/trusted_core.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
index d89fa2579ac0..4eb64548a74f 100644
--- a/include/keys/trusted-type.h
+++ b/include/keys/trusted-type.h
@@ -64,7 +64,7 @@ struct trusted_key_ops {
/* Unseal a key. */
int (*unseal)(struct trusted_key_payload *p, char *datablob);
- /* Get a randomized key. */
+ /* Optional: Get a randomized key. */
int (*get_random)(unsigned char *key, size_t key_len);
/* Exit key interface. */
diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
index 569af9af8df0..d2b7626cde8b 100644
--- a/security/keys/trusted-keys/trusted_core.c
+++ b/security/keys/trusted-keys/trusted_core.c
@@ -334,7 +334,7 @@ static int __init init_trusted(void)
continue;
get_random = trusted_key_sources[i].ops->get_random;
- if (trusted_kernel_rng)
+ if (trusted_kernel_rng || !get_random)
get_random = kernel_get_random;
static_call_update(trusted_key_init,
--
git-series 0.9.1
On Wed, 21 Jul 2021 at 22:19, Ahmad Fatoum <[email protected]> wrote:
>
> The two existing trusted key sources don't make use of the kernel RNG,
> but instead let the hardware doing the sealing/unsealing also
> generate the random key material. However, Users may want to place
> less trust into the quality of the trust source's random number
> generator and instead use the kernel entropy pool, which can be
> seeded from multiple entropy sources.
>
> Make this possible by adding a new trusted.kernel_rng parameter,
> that will force use of the kernel RNG. In its absence, it's up
> to the trust source to decide, which random numbers to use,
> maintaining the existing behavior.
>
> Suggested-by: Jarkko Sakkinen <[email protected]>
> Signed-off-by: Ahmad Fatoum <[email protected]>
> ---
> To: James Bottomley <[email protected]>
> To: Jarkko Sakkinen <[email protected]>
> To: Mimi Zohar <[email protected]>
> To: David Howells <[email protected]>
> Cc: James Morris <[email protected]>
> Cc: "Serge E. Hallyn" <[email protected]>
> Cc: "Horia Geantă" <[email protected]>
> Cc: Aymen Sghaier <[email protected]>
> Cc: Herbert Xu <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Udit Agarwal <[email protected]>
> Cc: Jan Luebbe <[email protected]>
> Cc: Eric Biggers <[email protected]>
> Cc: David Gstir <[email protected]>
> Cc: Richard Weinberger <[email protected]>
> Cc: Franck LENORMAND <[email protected]>
> Cc: Sumit Garg <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> ---
> Documentation/admin-guide/kernel-parameters.txt | 7 ++++++-
> Documentation/security/keys/trusted-encrypted.rst | 20 +++++++++-------
> security/keys/trusted-keys/trusted_core.c | 17 +++++++++++++-
> 3 files changed, 35 insertions(+), 9 deletions(-)
>
Sounds like a reasonable approach to me.
Acked-by: Sumit Garg <[email protected]>
-Sumit
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index bdb22006f713..0267ead88902 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -5734,6 +5734,13 @@
> first trust source as a backend which is initialized
> successfully during iteration.
>
> + trusted.kernel_rng = [KEYS]
> + Format: <bool>
> + When set to true (1), the kernel random number pool
> + is used to generate key material for trusted keys.
> + The default is to leave the RNG's choice to each
> + individual trust source.
> +
> tsc= Disable clocksource stability checks for TSC.
> Format: <string>
> [x86] reliable: mark tsc clocksource as reliable, this
> diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
> index 80d5a5af62a1..1d4b4b8f12f0 100644
> --- a/Documentation/security/keys/trusted-encrypted.rst
> +++ b/Documentation/security/keys/trusted-encrypted.rst
> @@ -87,22 +87,26 @@ Key Generation
> Trusted Keys
> ------------
>
> -New keys are created from random numbers generated in the trust source. They
> -are encrypted/decrypted using a child key in the storage key hierarchy.
> -Encryption and decryption of the child key must be protected by a strong
> -access control policy within the trust source.
> +New keys are created from random numbers. They are encrypted/decrypted using
> +a child key in the storage key hierarchy. Encryption and decryption of the
> +child key must be protected by a strong access control policy within the
> +trust source. The random number generator in use differs according to the
> +selected trust source:
>
> - * TPM (hardware device) based RNG
> + * TPM: hardware device based RNG
>
> - Strength of random numbers may vary from one device manufacturer to
> - another.
> + Keys are generated within the TPM. Strength of random numbers may vary
> + from one device manufacturer to another.
>
> - * TEE (OP-TEE based on Arm TrustZone) based RNG
> + * TEE: OP-TEE based on Arm TrustZone based RNG
>
> RNG is customizable as per platform needs. It can either be direct output
> from platform specific hardware RNG or a software based Fortuna CSPRNG
> which can be seeded via multiple entropy sources.
>
> +Optionally, users may specify ``trusted.kernel_rng=1`` on the kernel
> +command-line to override the used RNG with the kernel's random number pool.
> +
> Encrypted Keys
> --------------
>
> diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
> index 8cab69e5d0da..569af9af8df0 100644
> --- a/security/keys/trusted-keys/trusted_core.c
> +++ b/security/keys/trusted-keys/trusted_core.c
> @@ -16,12 +16,17 @@
> #include <linux/key-type.h>
> #include <linux/module.h>
> #include <linux/parser.h>
> +#include <linux/random.h>
> #include <linux/rcupdate.h>
> #include <linux/slab.h>
> #include <linux/static_call.h>
> #include <linux/string.h>
> #include <linux/uaccess.h>
>
> +static bool trusted_kernel_rng;
> +module_param_named(kernel_rng, trusted_kernel_rng, bool, 0);
> +MODULE_PARM_DESC(kernel_rng, "Generate key material from kernel RNG");
> +
> static char *trusted_key_source;
> module_param_named(source, trusted_key_source, charp, 0);
> MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)");
> @@ -312,8 +317,14 @@ struct key_type key_type_trusted = {
> };
> EXPORT_SYMBOL_GPL(key_type_trusted);
>
> +static int kernel_get_random(unsigned char *key, size_t key_len)
> +{
> + return get_random_bytes_wait(key, key_len) ?: key_len;
> +}
> +
> static int __init init_trusted(void)
> {
> + int (*get_random)(unsigned char *key, size_t key_len);
> int i, ret = 0;
>
> for (i = 0; i < ARRAY_SIZE(trusted_key_sources); i++) {
> @@ -322,6 +333,10 @@ static int __init init_trusted(void)
> strlen(trusted_key_sources[i].name)))
> continue;
>
> + get_random = trusted_key_sources[i].ops->get_random;
> + if (trusted_kernel_rng)
> + get_random = kernel_get_random;
> +
> static_call_update(trusted_key_init,
> trusted_key_sources[i].ops->init);
> static_call_update(trusted_key_seal,
> @@ -329,7 +344,7 @@ static int __init init_trusted(void)
> static_call_update(trusted_key_unseal,
> trusted_key_sources[i].ops->unseal);
> static_call_update(trusted_key_get_random,
> - trusted_key_sources[i].ops->get_random);
> + get_random);
> static_call_update(trusted_key_exit,
> trusted_key_sources[i].ops->exit);
> migratable = trusted_key_sources[i].ops->migratable;
> --
> git-series 0.9.1
On Wed, 21 Jul 2021 at 22:19, Ahmad Fatoum <[email protected]> wrote:
>
> The two existing trusted key sources don't make use of the kernel RNG,
> but instead let the hardware that does the sealing/unsealing also
> generate the random key material. While a previous change offers users
> the choice to use the kernel RNG instead for both, new trust sources
> may want to unconditionally use the kernel RNG for generating key
> material, like it's done elsewhere in the kernel.
>
> This is especially prudent for hardware that has proven-in-production
> HWRNG drivers implemented, as otherwise code would have to be duplicated
> only to arrive at a possibly worse result.
>
> Make this possible by turning struct trusted_key_ops::get_random
> into an optional member. If a driver leaves it NULL, kernel RNG
> will be used instead.
>
> Signed-off-by: Ahmad Fatoum <[email protected]>
> ---
> To: James Bottomley <[email protected]>
> To: Jarkko Sakkinen <[email protected]>
> To: Mimi Zohar <[email protected]>
> To: David Howells <[email protected]>
> Cc: James Morris <[email protected]>
> Cc: "Serge E. Hallyn" <[email protected]>
> Cc: "Horia Geantă" <[email protected]>
> Cc: Aymen Sghaier <[email protected]>
> Cc: Herbert Xu <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Udit Agarwal <[email protected]>
> Cc: Eric Biggers <[email protected]>
> Cc: Jan Luebbe <[email protected]>
> Cc: David Gstir <[email protected]>
> Cc: Richard Weinberger <[email protected]>
> Cc: Franck LENORMAND <[email protected]>
> Cc: Sumit Garg <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> ---
> include/keys/trusted-type.h | 2 +-
> security/keys/trusted-keys/trusted_core.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
> index d89fa2579ac0..4eb64548a74f 100644
> --- a/include/keys/trusted-type.h
> +++ b/include/keys/trusted-type.h
> @@ -64,7 +64,7 @@ struct trusted_key_ops {
> /* Unseal a key. */
> int (*unseal)(struct trusted_key_payload *p, char *datablob);
>
> - /* Get a randomized key. */
> + /* Optional: Get a randomized key. */
> int (*get_random)(unsigned char *key, size_t key_len);
>
> /* Exit key interface. */
> diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
> index 569af9af8df0..d2b7626cde8b 100644
> --- a/security/keys/trusted-keys/trusted_core.c
> +++ b/security/keys/trusted-keys/trusted_core.c
> @@ -334,7 +334,7 @@ static int __init init_trusted(void)
> continue;
>
> get_random = trusted_key_sources[i].ops->get_random;
> - if (trusted_kernel_rng)
> + if (trusted_kernel_rng || !get_random)
> get_random = kernel_get_random;
>
For ease of understanding, I would prefer to write it as:
get_random = trusted_key_sources[i].ops->get_random ?:
kernel_get_random;
if (trusted_kernel_rng)
get_random = kernel_get_random;
With that:
Acked-by: Sumit Garg <[email protected]>
-Sumit
> static_call_update(trusted_key_init,
> --
> git-series 0.9.1
Dear trusted key maintainers,
On 21.07.21 18:48, Ahmad Fatoum wrote:
> Series applies on top of
> https://lore.kernel.org/linux-integrity/[email protected]/T/#u
>
> v2 -> v3:
> - Split off first Kconfig preparation patch. It fixes a regression,
> so sent that out, so it can be applied separately (Sumit)
> - Split off second key import patch. I'll send that out separately
> as it's a development aid and not required within the CAAM series
> - add MAINTAINERS entry
Gentle ping. I'd appreciate feedback on this series.
Cheers,
Ahmad
>
> v1 -> v2:
> - Added new commit to make trusted key Kconfig option independent
> of TPM and added new Kconfig file for trusted keys
> - Add new commit for importing existing key material
> - Allow users to force use of kernel RNG (Jarkko)
> - Enforce maximum keymod size (Horia)
> - Use append_seq_(in|out)_ptr_intlen instead of append_seq_(in|out)_ptr
> (Horia)
> - Make blobifier handle private to CAAM glue code file (Horia)
> - Extend trusted keys documentation for CAAM
> - Rebased and updated original cover letter:
>
> The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
> built into many newer i.MX and QorIQ SoCs by NXP.
>
> Its blob mechanism can AES encrypt/decrypt user data using a unique
> never-disclosed device-specific key.
>
> There has been multiple discussions on how to represent this within the kernel:
>
> The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
> built into many newer i.MX and QorIQ SoCs by NXP.
>
> Its blob mechanism can AES encrypt/decrypt user data using a unique
> never-disclosed device-specific key. There has been multiple
> discussions on how to represent this within the kernel:
>
> - [RFC] crypto: caam - add red blobifier
> Steffen implemented[1] a PoC sysfs driver to start a discussion on how to
> best integrate the blob mechanism.
> Mimi suggested that it could be used to implement trusted keys.
> Trusted keys back then were a TPM-only feature.
>
> - security/keys/secure_key: Adds the secure key support based on CAAM.
> Udit added[2] a new "secure" key type with the CAAM as backend. The key
> material stays within the kernel only.
> Mimi and James agreed that this needs a generic interface, not specific
> to CAAM. Mimi suggested trusted keys. Jan noted that this could serve as
> basis for TEE-backed keys.
>
> - [RFC] drivers: crypto: caam: key: Add caam_tk key type
> Franck added[3] a new "caam_tk" key type based on Udit's work. This time
> it uses CAAM "black blobs" instead of "red blobs", so key material stays
> within the CAAM and isn't exposed to kernel in plaintext.
> James voiced the opinion that there should be just one user-facing generic
> wrap/unwrap key type with multiple possible handlers.
> David suggested trusted keys.
>
> - Introduce TEE based Trusted Keys support
> Sumit reworked[4] trusted keys to support multiple possible backends with
> one chosen at boot time and added a new TEE backend along with TPM.
> This now sits in Jarkko's master branch to be sent out for v5.13
>
> This patch series builds on top of Sumit's rework to have the CAAM as yet another
> trusted key backend.
>
> The CAAM bits are based on Steffen's initial patch from 2015. His work had been
> used in the field for some years now, so I preferred not to deviate too much from it.
>
> This series has been tested with dmcrypt[5] on an i.MX6DL.
>
> Looking forward to your feedback.
>
> Cheers,
> Ahmad
>
> [1]: https://lore.kernel.org/linux-crypto/[email protected]/
> [2]: https://lore.kernel.org/linux-integrity/[email protected]/
> [3]: https://lore.kernel.org/lkml/[email protected]/
> [4]: https://lore.kernel.org/lkml/[email protected]/
> [5]: https://lore.kernel.org/linux-integrity/[email protected]/
>
> ---
> To: Jarkko Sakkinen <[email protected]>
> To: "Horia Geantă" <[email protected]>
> To: Mimi Zohar <[email protected]>
> To: Aymen Sghaier <[email protected]>
> To: Herbert Xu <[email protected]>
> To: "David S. Miller" <[email protected]>
> To: James Bottomley <[email protected]>
> Cc: David Howells <[email protected]>
> Cc: James Morris <[email protected]>
> Cc: "Serge E. Hallyn" <[email protected]>
> Cc: Steffen Trumtrar <[email protected]>
> Cc: Udit Agarwal <[email protected]>
> Cc: Jan Luebbe <[email protected]>
> Cc: David Gstir <[email protected]>
> Cc: Eric Biggers <[email protected]>
> Cc: Richard Weinberger <[email protected]>
> Cc: Franck LENORMAND <[email protected]>
> Cc: Sumit Garg <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
>
> Ahmad Fatoum (4):
> KEYS: trusted: allow users to use kernel RNG for key material
> KEYS: trusted: allow trust sources to use kernel RNG for key material
> crypto: caam - add in-kernel interface for blob generator
> KEYS: trusted: Introduce support for NXP CAAM-based trusted keys
>
> Documentation/admin-guide/kernel-parameters.txt | 8 +-
> Documentation/security/keys/trusted-encrypted.rst | 60 +++-
> MAINTAINERS | 9 +-
> drivers/crypto/caam/Kconfig | 3 +-
> drivers/crypto/caam/Makefile | 1 +-
> drivers/crypto/caam/blob_gen.c | 230 +++++++++++++++-
> include/keys/trusted-type.h | 2 +-
> include/keys/trusted_caam.h | 11 +-
> include/soc/fsl/caam-blob.h | 56 ++++-
> security/keys/trusted-keys/Kconfig | 11 +-
> security/keys/trusted-keys/Makefile | 2 +-
> security/keys/trusted-keys/trusted_caam.c | 74 +++++-
> security/keys/trusted-keys/trusted_core.c | 23 +-
> 13 files changed, 477 insertions(+), 13 deletions(-)
> create mode 100644 drivers/crypto/caam/blob_gen.c
> create mode 100644 include/keys/trusted_caam.h
> create mode 100644 include/soc/fsl/caam-blob.h
> create mode 100644 security/keys/trusted-keys/trusted_caam.c
>
> base-commit: 97408d81ed533b953326c580ff2c3f1948b3fcee
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
Hello Sumit,
On 22.07.21 08:31, Sumit Garg wrote:
> On Wed, 21 Jul 2021 at 22:19, Ahmad Fatoum <[email protected]> wrote:
>>
>> The two existing trusted key sources don't make use of the kernel RNG,
>> but instead let the hardware that does the sealing/unsealing also
>> generate the random key material. While a previous change offers users
>> the choice to use the kernel RNG instead for both, new trust sources
>> may want to unconditionally use the kernel RNG for generating key
>> material, like it's done elsewhere in the kernel.
>>
>> This is especially prudent for hardware that has proven-in-production
>> HWRNG drivers implemented, as otherwise code would have to be duplicated
>> only to arrive at a possibly worse result.
>>
>> Make this possible by turning struct trusted_key_ops::get_random
>> into an optional member. If a driver leaves it NULL, kernel RNG
>> will be used instead.
>>
>> Signed-off-by: Ahmad Fatoum <[email protected]>
>> ---
>> To: James Bottomley <[email protected]>
>> To: Jarkko Sakkinen <[email protected]>
>> To: Mimi Zohar <[email protected]>
>> To: David Howells <[email protected]>
>> Cc: James Morris <[email protected]>
>> Cc: "Serge E. Hallyn" <[email protected]>
>> Cc: "Horia Geantă" <[email protected]>
>> Cc: Aymen Sghaier <[email protected]>
>> Cc: Herbert Xu <[email protected]>
>> Cc: "David S. Miller" <[email protected]>
>> Cc: Udit Agarwal <[email protected]>
>> Cc: Eric Biggers <[email protected]>
>> Cc: Jan Luebbe <[email protected]>
>> Cc: David Gstir <[email protected]>
>> Cc: Richard Weinberger <[email protected]>
>> Cc: Franck LENORMAND <[email protected]>
>> Cc: Sumit Garg <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> ---
>> include/keys/trusted-type.h | 2 +-
>> security/keys/trusted-keys/trusted_core.c | 2 +-
>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
>> index d89fa2579ac0..4eb64548a74f 100644
>> --- a/include/keys/trusted-type.h
>> +++ b/include/keys/trusted-type.h
>> @@ -64,7 +64,7 @@ struct trusted_key_ops {
>> /* Unseal a key. */
>> int (*unseal)(struct trusted_key_payload *p, char *datablob);
>>
>> - /* Get a randomized key. */
>> + /* Optional: Get a randomized key. */
>> int (*get_random)(unsigned char *key, size_t key_len);
>>
>> /* Exit key interface. */
>> diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
>> index 569af9af8df0..d2b7626cde8b 100644
>> --- a/security/keys/trusted-keys/trusted_core.c
>> +++ b/security/keys/trusted-keys/trusted_core.c
>> @@ -334,7 +334,7 @@ static int __init init_trusted(void)
>> continue;
>>
>> get_random = trusted_key_sources[i].ops->get_random;
>> - if (trusted_kernel_rng)
>> + if (trusted_kernel_rng || !get_random)
>> get_random = kernel_get_random;
>>
>
> For ease of understanding, I would prefer to write it as:
>
> get_random = trusted_key_sources[i].ops->get_random ?:
> kernel_get_random;
> if (trusted_kernel_rng)
> get_random = kernel_get_random;
>
> With that:
>
> Acked-by: Sumit Garg <[email protected]>
I don't think it improves readability to split up the conditional.
At least I need to take a second pass over the code to understand
the second conditional.
Cheers,
Ahmad
>
> -Sumit
>
>> static_call_update(trusted_key_init,
>> --
>> git-series 0.9.1
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
On Fri, Aug 06, 2021 at 05:12:19PM +0200, Ahmad Fatoum wrote:
> Dear trusted key maintainers,
>
> On 21.07.21 18:48, Ahmad Fatoum wrote:
> > Series applies on top of
> > https://lore.kernel.org/linux-integrity/[email protected]/T/#u
> >
> > v2 -> v3:
> > - Split off first Kconfig preparation patch. It fixes a regression,
> > so sent that out, so it can be applied separately (Sumit)
> > - Split off second key import patch. I'll send that out separately
> > as it's a development aid and not required within the CAAM series
> > - add MAINTAINERS entry
>
> Gentle ping. I'd appreciate feedback on this series.
Simple question: what is fscrypt?
/Jarkko
On Mon, Aug 09, 2021 at 09:52:20AM +0200, Ahmad Fatoum wrote:
> Hello Sumit,
>
> On 22.07.21 08:31, Sumit Garg wrote:
> > On Wed, 21 Jul 2021 at 22:19, Ahmad Fatoum <[email protected]> wrote:
> >>
> >> The two existing trusted key sources don't make use of the kernel RNG,
> >> but instead let the hardware that does the sealing/unsealing also
> >> generate the random key material. While a previous change offers users
> >> the choice to use the kernel RNG instead for both, new trust sources
> >> may want to unconditionally use the kernel RNG for generating key
> >> material, like it's done elsewhere in the kernel.
> >>
> >> This is especially prudent for hardware that has proven-in-production
> >> HWRNG drivers implemented, as otherwise code would have to be duplicated
> >> only to arrive at a possibly worse result.
> >>
> >> Make this possible by turning struct trusted_key_ops::get_random
> >> into an optional member. If a driver leaves it NULL, kernel RNG
> >> will be used instead.
> >>
> >> Signed-off-by: Ahmad Fatoum <[email protected]>
> >> ---
> >> To: James Bottomley <[email protected]>
> >> To: Jarkko Sakkinen <[email protected]>
> >> To: Mimi Zohar <[email protected]>
> >> To: David Howells <[email protected]>
> >> Cc: James Morris <[email protected]>
> >> Cc: "Serge E. Hallyn" <[email protected]>
> >> Cc: "Horia Geantă" <[email protected]>
> >> Cc: Aymen Sghaier <[email protected]>
> >> Cc: Herbert Xu <[email protected]>
> >> Cc: "David S. Miller" <[email protected]>
> >> Cc: Udit Agarwal <[email protected]>
> >> Cc: Eric Biggers <[email protected]>
> >> Cc: Jan Luebbe <[email protected]>
> >> Cc: David Gstir <[email protected]>
> >> Cc: Richard Weinberger <[email protected]>
> >> Cc: Franck LENORMAND <[email protected]>
> >> Cc: Sumit Garg <[email protected]>
> >> Cc: [email protected]
> >> Cc: [email protected]
> >> Cc: [email protected]
> >> Cc: [email protected]
> >> Cc: [email protected]
> >> ---
> >> include/keys/trusted-type.h | 2 +-
> >> security/keys/trusted-keys/trusted_core.c | 2 +-
> >> 2 files changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
> >> index d89fa2579ac0..4eb64548a74f 100644
> >> --- a/include/keys/trusted-type.h
> >> +++ b/include/keys/trusted-type.h
> >> @@ -64,7 +64,7 @@ struct trusted_key_ops {
> >> /* Unseal a key. */
> >> int (*unseal)(struct trusted_key_payload *p, char *datablob);
> >>
> >> - /* Get a randomized key. */
> >> + /* Optional: Get a randomized key. */
> >> int (*get_random)(unsigned char *key, size_t key_len);
> >>
> >> /* Exit key interface. */
> >> diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
> >> index 569af9af8df0..d2b7626cde8b 100644
> >> --- a/security/keys/trusted-keys/trusted_core.c
> >> +++ b/security/keys/trusted-keys/trusted_core.c
> >> @@ -334,7 +334,7 @@ static int __init init_trusted(void)
> >> continue;
> >>
> >> get_random = trusted_key_sources[i].ops->get_random;
> >> - if (trusted_kernel_rng)
> >> + if (trusted_kernel_rng || !get_random)
> >> get_random = kernel_get_random;
> >>
> >
> > For ease of understanding, I would prefer to write it as:
> >
> > get_random = trusted_key_sources[i].ops->get_random ?:
> > kernel_get_random;
> > if (trusted_kernel_rng)
> > get_random = kernel_get_random;
> >
> > With that:
> >
> > Acked-by: Sumit Garg <[email protected]>
>
> I don't think it improves readability to split up the conditional.
> At least I need to take a second pass over the code to understand
> the second conditional.
Ternary operators are pain to read, unless a super trivial case.
I'd stick to what you did.
/Jarkko
On 09.08.21 11:35, Jarkko Sakkinen wrote:
> On Fri, Aug 06, 2021 at 05:12:19PM +0200, Ahmad Fatoum wrote:
>> Dear trusted key maintainers,
>>
>> On 21.07.21 18:48, Ahmad Fatoum wrote:
>>> Series applies on top of
>>> https://lore.kernel.org/linux-integrity/[email protected]/T/#u
>>>
>>> v2 -> v3:
>>> - Split off first Kconfig preparation patch. It fixes a regression,
>>> so sent that out, so it can be applied separately (Sumit)
>>> - Split off second key import patch. I'll send that out separately
>>> as it's a development aid and not required within the CAAM series
>>> - add MAINTAINERS entry
>>
>> Gentle ping. I'd appreciate feedback on this series.
>
> Simple question: what is fscrypt?
For supported file systems, fscrypt[1] allows you to encrypt at a directory level.
It has no trusted key integration yet, which is something I am trying to upstream
in parallel to this series, so I eventually can use fscrypt together with CAAM-backed
trusted keys on an unpatched kernel.
If it interests you, I described[2] my CAAM+ubifs+fscrypt use case in the
discussion thread on my fscrypt-trusted-keys v1. Jan, a colleague of mine, held a
talk[3] on the different solutions for authenticated and encrypted storage, which
you may want to check out.
I'd really appreciate feedback here on the the CAAM parts of this series, so this can
eventually go mainline.
Thanks,
Ahmad
[1]: https://www.kernel.org/doc/html/v5.13/filesystems/fscrypt.html
[2]: https://lore.kernel.org/linux-fscrypt/[email protected]/
[3]: https://www.youtube.com/watch?v=z_y84v9076c
>
> /Jarkko
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
On Mon, 9 Aug 2021 at 15:26, Jarkko Sakkinen <[email protected]> wrote:
>
> On Mon, Aug 09, 2021 at 09:52:20AM +0200, Ahmad Fatoum wrote:
> > Hello Sumit,
> >
> > On 22.07.21 08:31, Sumit Garg wrote:
> > > On Wed, 21 Jul 2021 at 22:19, Ahmad Fatoum <[email protected]> wrote:
> > >>
> > >> The two existing trusted key sources don't make use of the kernel RNG,
> > >> but instead let the hardware that does the sealing/unsealing also
> > >> generate the random key material. While a previous change offers users
> > >> the choice to use the kernel RNG instead for both, new trust sources
> > >> may want to unconditionally use the kernel RNG for generating key
> > >> material, like it's done elsewhere in the kernel.
> > >>
> > >> This is especially prudent for hardware that has proven-in-production
> > >> HWRNG drivers implemented, as otherwise code would have to be duplicated
> > >> only to arrive at a possibly worse result.
> > >>
> > >> Make this possible by turning struct trusted_key_ops::get_random
> > >> into an optional member. If a driver leaves it NULL, kernel RNG
> > >> will be used instead.
> > >>
> > >> Signed-off-by: Ahmad Fatoum <[email protected]>
> > >> ---
> > >> To: James Bottomley <[email protected]>
> > >> To: Jarkko Sakkinen <[email protected]>
> > >> To: Mimi Zohar <[email protected]>
> > >> To: David Howells <[email protected]>
> > >> Cc: James Morris <[email protected]>
> > >> Cc: "Serge E. Hallyn" <[email protected]>
> > >> Cc: "Horia Geantă" <[email protected]>
> > >> Cc: Aymen Sghaier <[email protected]>
> > >> Cc: Herbert Xu <[email protected]>
> > >> Cc: "David S. Miller" <[email protected]>
> > >> Cc: Udit Agarwal <[email protected]>
> > >> Cc: Eric Biggers <[email protected]>
> > >> Cc: Jan Luebbe <[email protected]>
> > >> Cc: David Gstir <[email protected]>
> > >> Cc: Richard Weinberger <[email protected]>
> > >> Cc: Franck LENORMAND <[email protected]>
> > >> Cc: Sumit Garg <[email protected]>
> > >> Cc: [email protected]
> > >> Cc: [email protected]
> > >> Cc: [email protected]
> > >> Cc: [email protected]
> > >> Cc: [email protected]
> > >> ---
> > >> include/keys/trusted-type.h | 2 +-
> > >> security/keys/trusted-keys/trusted_core.c | 2 +-
> > >> 2 files changed, 2 insertions(+), 2 deletions(-)
> > >>
> > >> diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
> > >> index d89fa2579ac0..4eb64548a74f 100644
> > >> --- a/include/keys/trusted-type.h
> > >> +++ b/include/keys/trusted-type.h
> > >> @@ -64,7 +64,7 @@ struct trusted_key_ops {
> > >> /* Unseal a key. */
> > >> int (*unseal)(struct trusted_key_payload *p, char *datablob);
> > >>
> > >> - /* Get a randomized key. */
> > >> + /* Optional: Get a randomized key. */
> > >> int (*get_random)(unsigned char *key, size_t key_len);
> > >>
> > >> /* Exit key interface. */
> > >> diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
> > >> index 569af9af8df0..d2b7626cde8b 100644
> > >> --- a/security/keys/trusted-keys/trusted_core.c
> > >> +++ b/security/keys/trusted-keys/trusted_core.c
> > >> @@ -334,7 +334,7 @@ static int __init init_trusted(void)
> > >> continue;
> > >>
> > >> get_random = trusted_key_sources[i].ops->get_random;
> > >> - if (trusted_kernel_rng)
> > >> + if (trusted_kernel_rng || !get_random)
> > >> get_random = kernel_get_random;
> > >>
> > >
> > > For ease of understanding, I would prefer to write it as:
> > >
> > > get_random = trusted_key_sources[i].ops->get_random ?:
> > > kernel_get_random;
> > > if (trusted_kernel_rng)
> > > get_random = kernel_get_random;
> > >
> > > With that:
> > >
> > > Acked-by: Sumit Garg <[email protected]>
> >
> > I don't think it improves readability to split up the conditional.
> > At least I need to take a second pass over the code to understand
> > the second conditional.
>
> Ternary operators are pain to read, unless a super trivial case.
>
> I'd stick to what you did.
Fair enough, I am fine with the current patch.
-Sumit
>
> /Jarkko
Hi Ahmad,
> On 09.08.2021, at 12:16, Ahmad Fatoum <[email protected]> wrote:
[...]
> If it interests you, I described[2] my CAAM+ubifs+fscrypt use case in the
> discussion thread on my fscrypt-trusted-keys v1. Jan, a colleague of mine, held a
> talk[3] on the different solutions for authenticated and encrypted storage, which
> you may want to check out.
>
> I'd really appreciate feedback here on the the CAAM parts of this series, so this can
> eventually go mainline.
Since you mention the fscrypt trusted-keys use case:
I noticed that the key length for trusted-keys is limited to
256 - 1024bit keys. fscrypt does however also support keys
with e.g. 128bit keys (AES-128-CBC-ESSIV, AES-128-CTS-CBC).
AFAIK, CAAM and TEE key blobs would also support key lengths outside the 256 - 1024bit range.
Wouldn’t it make sense to align the supported key lengths?
I.e. extend the range of supported key lengths for trusted keys.
Or is there a specific reason why key lengths below 256bit are
not supported by trusted-keys?
Cheers,
David
On Wed, Jul 21, 2021 at 9:49 AM Ahmad Fatoum <[email protected]> wrote:
>
> Series applies on top of
> https://lore.kernel.org/linux-integrity/[email protected]/T/#u
>
> v2 -> v3:
> - Split off first Kconfig preparation patch. It fixes a regression,
> so sent that out, so it can be applied separately (Sumit)
> - Split off second key import patch. I'll send that out separately
> as it's a development aid and not required within the CAAM series
> - add MAINTAINERS entry
>
> v1 -> v2:
> - Added new commit to make trusted key Kconfig option independent
> of TPM and added new Kconfig file for trusted keys
> - Add new commit for importing existing key material
> - Allow users to force use of kernel RNG (Jarkko)
> - Enforce maximum keymod size (Horia)
> - Use append_seq_(in|out)_ptr_intlen instead of append_seq_(in|out)_ptr
> (Horia)
> - Make blobifier handle private to CAAM glue code file (Horia)
> - Extend trusted keys documentation for CAAM
> - Rebased and updated original cover letter:
>
> The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
> built into many newer i.MX and QorIQ SoCs by NXP.
>
> Its blob mechanism can AES encrypt/decrypt user data using a unique
> never-disclosed device-specific key.
>
> There has been multiple discussions on how to represent this within the kernel:
>
> The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
> built into many newer i.MX and QorIQ SoCs by NXP.
>
> Its blob mechanism can AES encrypt/decrypt user data using a unique
> never-disclosed device-specific key. There has been multiple
> discussions on how to represent this within the kernel:
>
> - [RFC] crypto: caam - add red blobifier
> Steffen implemented[1] a PoC sysfs driver to start a discussion on how to
> best integrate the blob mechanism.
> Mimi suggested that it could be used to implement trusted keys.
> Trusted keys back then were a TPM-only feature.
>
> - security/keys/secure_key: Adds the secure key support based on CAAM.
> Udit added[2] a new "secure" key type with the CAAM as backend. The key
> material stays within the kernel only.
> Mimi and James agreed that this needs a generic interface, not specific
> to CAAM. Mimi suggested trusted keys. Jan noted that this could serve as
> basis for TEE-backed keys.
>
> - [RFC] drivers: crypto: caam: key: Add caam_tk key type
> Franck added[3] a new "caam_tk" key type based on Udit's work. This time
> it uses CAAM "black blobs" instead of "red blobs", so key material stays
> within the CAAM and isn't exposed to kernel in plaintext.
> James voiced the opinion that there should be just one user-facing generic
> wrap/unwrap key type with multiple possible handlers.
> David suggested trusted keys.
>
> - Introduce TEE based Trusted Keys support
> Sumit reworked[4] trusted keys to support multiple possible backends with
> one chosen at boot time and added a new TEE backend along with TPM.
> This now sits in Jarkko's master branch to be sent out for v5.13
>
> This patch series builds on top of Sumit's rework to have the CAAM as yet another
> trusted key backend.
>
> The CAAM bits are based on Steffen's initial patch from 2015. His work had been
> used in the field for some years now, so I preferred not to deviate too much from it.
>
> This series has been tested with dmcrypt[5] on an i.MX6DL.
>
> Looking forward to your feedback.
>
> Cheers,
> Ahmad
>
> [1]: https://lore.kernel.org/linux-crypto/[email protected]/
> [2]: https://lore.kernel.org/linux-integrity/[email protected]/
> [3]: https://lore.kernel.org/lkml/[email protected]/
> [4]: https://lore.kernel.org/lkml/[email protected]/
> [5]: https://lore.kernel.org/linux-integrity/[email protected]/
>
> ---
> To: Jarkko Sakkinen <[email protected]>
> To: "Horia Geantă" <[email protected]>
> To: Mimi Zohar <[email protected]>
> To: Aymen Sghaier <[email protected]>
> To: Herbert Xu <[email protected]>
> To: "David S. Miller" <[email protected]>
> To: James Bottomley <[email protected]>
> Cc: David Howells <[email protected]>
> Cc: James Morris <[email protected]>
> Cc: "Serge E. Hallyn" <[email protected]>
> Cc: Steffen Trumtrar <[email protected]>
> Cc: Udit Agarwal <[email protected]>
> Cc: Jan Luebbe <[email protected]>
> Cc: David Gstir <[email protected]>
> Cc: Eric Biggers <[email protected]>
> Cc: Richard Weinberger <[email protected]>
> Cc: Franck LENORMAND <[email protected]>
> Cc: Sumit Garg <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
>
> Ahmad Fatoum (4):
> KEYS: trusted: allow users to use kernel RNG for key material
> KEYS: trusted: allow trust sources to use kernel RNG for key material
> crypto: caam - add in-kernel interface for blob generator
> KEYS: trusted: Introduce support for NXP CAAM-based trusted keys
>
> Documentation/admin-guide/kernel-parameters.txt | 8 +-
> Documentation/security/keys/trusted-encrypted.rst | 60 +++-
> MAINTAINERS | 9 +-
> drivers/crypto/caam/Kconfig | 3 +-
> drivers/crypto/caam/Makefile | 1 +-
> drivers/crypto/caam/blob_gen.c | 230 +++++++++++++++-
> include/keys/trusted-type.h | 2 +-
> include/keys/trusted_caam.h | 11 +-
> include/soc/fsl/caam-blob.h | 56 ++++-
> security/keys/trusted-keys/Kconfig | 11 +-
> security/keys/trusted-keys/Makefile | 2 +-
> security/keys/trusted-keys/trusted_caam.c | 74 +++++-
> security/keys/trusted-keys/trusted_core.c | 23 +-
> 13 files changed, 477 insertions(+), 13 deletions(-)
> create mode 100644 drivers/crypto/caam/blob_gen.c
> create mode 100644 include/keys/trusted_caam.h
> create mode 100644 include/soc/fsl/caam-blob.h
> create mode 100644 security/keys/trusted-keys/trusted_caam.c
>
> base-commit: 97408d81ed533b953326c580ff2c3f1948b3fcee
> --
> git-series 0.9.1
Ahmad,
Thanks for your work!
I've been asked to integrate the capability of using CAAM to
blob/deblob data to an older 5.4 kernel such as NXP's downstream
vendor kernel does [1] and I'm trying to understand how your series
works. I'm not at all familiar with the Linux Key Management API's or
trusted keys. Can you provide an example of how this can be used for
such a thing?
Best regards,
Tim
[1] https://source.codeaurora.org/external/imxsupport/imx_sec_apps/tree/demo-caam-blobs/README.txt
Hello Tim,
On 20.08.21 17:39, Tim Harvey wrote:
> On Wed, Jul 21, 2021 at 9:49 AM Ahmad Fatoum <[email protected]> wrote:
>>
>> Series applies on top of
>> https://lore.kernel.org/linux-integrity/[email protected]/T/#u
>>
>> v2 -> v3:
>> - Split off first Kconfig preparation patch. It fixes a regression,
>> so sent that out, so it can be applied separately (Sumit)
>> - Split off second key import patch. I'll send that out separately
>> as it's a development aid and not required within the CAAM series
>> - add MAINTAINERS entry
>>
>> v1 -> v2:
>> - Added new commit to make trusted key Kconfig option independent
>> of TPM and added new Kconfig file for trusted keys
>> - Add new commit for importing existing key material
>> - Allow users to force use of kernel RNG (Jarkko)
>> - Enforce maximum keymod size (Horia)
>> - Use append_seq_(in|out)_ptr_intlen instead of append_seq_(in|out)_ptr
>> (Horia)
>> - Make blobifier handle private to CAAM glue code file (Horia)
>> - Extend trusted keys documentation for CAAM
>> - Rebased and updated original cover letter:
>>
>> The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
>> built into many newer i.MX and QorIQ SoCs by NXP.
>>
>> Its blob mechanism can AES encrypt/decrypt user data using a unique
>> never-disclosed device-specific key.
>>
>> There has been multiple discussions on how to represent this within the kernel:
>>
>> The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
>> built into many newer i.MX and QorIQ SoCs by NXP.
>>
>> Its blob mechanism can AES encrypt/decrypt user data using a unique
>> never-disclosed device-specific key. There has been multiple
>> discussions on how to represent this within the kernel:
>>
>> - [RFC] crypto: caam - add red blobifier
>> Steffen implemented[1] a PoC sysfs driver to start a discussion on how to
>> best integrate the blob mechanism.
>> Mimi suggested that it could be used to implement trusted keys.
>> Trusted keys back then were a TPM-only feature.
>>
>> - security/keys/secure_key: Adds the secure key support based on CAAM.
>> Udit added[2] a new "secure" key type with the CAAM as backend. The key
>> material stays within the kernel only.
>> Mimi and James agreed that this needs a generic interface, not specific
>> to CAAM. Mimi suggested trusted keys. Jan noted that this could serve as
>> basis for TEE-backed keys.
>>
>> - [RFC] drivers: crypto: caam: key: Add caam_tk key type
>> Franck added[3] a new "caam_tk" key type based on Udit's work. This time
>> it uses CAAM "black blobs" instead of "red blobs", so key material stays
>> within the CAAM and isn't exposed to kernel in plaintext.
>> James voiced the opinion that there should be just one user-facing generic
>> wrap/unwrap key type with multiple possible handlers.
>> David suggested trusted keys.
>>
>> - Introduce TEE based Trusted Keys support
>> Sumit reworked[4] trusted keys to support multiple possible backends with
>> one chosen at boot time and added a new TEE backend along with TPM.
>> This now sits in Jarkko's master branch to be sent out for v5.13
>>
>> This patch series builds on top of Sumit's rework to have the CAAM as yet another
>> trusted key backend.
>>
>> The CAAM bits are based on Steffen's initial patch from 2015. His work had been
>> used in the field for some years now, so I preferred not to deviate too much from it.
>>
>> This series has been tested with dmcrypt[5] on an i.MX6DL.
>>
>> Looking forward to your feedback.
>>
>> Cheers,
>> Ahmad
>>
>> [1]: https://lore.kernel.org/linux-crypto/[email protected]/
>> [2]: https://lore.kernel.org/linux-integrity/[email protected]/
>> [3]: https://lore.kernel.org/lkml/[email protected]/
>> [4]: https://lore.kernel.org/lkml/[email protected]/
>> [5]: https://lore.kernel.org/linux-integrity/[email protected]/
>>
>> ---
>> To: Jarkko Sakkinen <[email protected]>
>> To: "Horia Geantă" <[email protected]>
>> To: Mimi Zohar <[email protected]>
>> To: Aymen Sghaier <[email protected]>
>> To: Herbert Xu <[email protected]>
>> To: "David S. Miller" <[email protected]>
>> To: James Bottomley <[email protected]>
>> Cc: David Howells <[email protected]>
>> Cc: James Morris <[email protected]>
>> Cc: "Serge E. Hallyn" <[email protected]>
>> Cc: Steffen Trumtrar <[email protected]>
>> Cc: Udit Agarwal <[email protected]>
>> Cc: Jan Luebbe <[email protected]>
>> Cc: David Gstir <[email protected]>
>> Cc: Eric Biggers <[email protected]>
>> Cc: Richard Weinberger <[email protected]>
>> Cc: Franck LENORMAND <[email protected]>
>> Cc: Sumit Garg <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>>
>> Ahmad Fatoum (4):
>> KEYS: trusted: allow users to use kernel RNG for key material
>> KEYS: trusted: allow trust sources to use kernel RNG for key material
>> crypto: caam - add in-kernel interface for blob generator
>> KEYS: trusted: Introduce support for NXP CAAM-based trusted keys
>>
>> Documentation/admin-guide/kernel-parameters.txt | 8 +-
>> Documentation/security/keys/trusted-encrypted.rst | 60 +++-
>> MAINTAINERS | 9 +-
>> drivers/crypto/caam/Kconfig | 3 +-
>> drivers/crypto/caam/Makefile | 1 +-
>> drivers/crypto/caam/blob_gen.c | 230 +++++++++++++++-
>> include/keys/trusted-type.h | 2 +-
>> include/keys/trusted_caam.h | 11 +-
>> include/soc/fsl/caam-blob.h | 56 ++++-
>> security/keys/trusted-keys/Kconfig | 11 +-
>> security/keys/trusted-keys/Makefile | 2 +-
>> security/keys/trusted-keys/trusted_caam.c | 74 +++++-
>> security/keys/trusted-keys/trusted_core.c | 23 +-
>> 13 files changed, 477 insertions(+), 13 deletions(-)
>> create mode 100644 drivers/crypto/caam/blob_gen.c
>> create mode 100644 include/keys/trusted_caam.h
>> create mode 100644 include/soc/fsl/caam-blob.h
>> create mode 100644 security/keys/trusted-keys/trusted_caam.c
>>
>> base-commit: 97408d81ed533b953326c580ff2c3f1948b3fcee
>> --
>> git-series 0.9.1
>
> Ahmad,
>
> Thanks for your work!
>
> I've been asked to integrate the capability of using CAAM to
> blob/deblob data to an older 5.4 kernel such as NXP's downstream
> vendor kernel does [1] and I'm trying to understand how your series
> works. I'm not at all familiar with the Linux Key Management API's or
> trusted keys. Can you provide an example of how this can be used for
> such a thing?
Here's an example with dm-crypt:
https://lore.kernel.org/linux-integrity/[email protected]/
dm-crypt is a bit special at the moment, because it has direct support for
trusted keys. For interfacing with other parts of the kernel like ecryptfs
or EVM, you have to create encrypted keys rooted to the trusted keys and use
those. The kernel documentation has an example:
https://www.kernel.org/doc/html/v5.13/security/keys/trusted-encrypted.html
If you backport this series, you can include the typo fix spotted by David.
I'll send out a revised series, but given that a regression fix I want to
rebase on hasn't been picked up for 3 weeks now, I am not in a hurry.
Cheers,
Ahmad
>
> Best regards,
>
> Tim
> [1] https://source.codeaurora.org/external/imxsupport/imx_sec_apps/tree/demo-caam-blobs/README.txt
>
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
Hello David,
On 10.08.21 13:28, David Gstir wrote:
> Hi Ahmad,
>
>> On 09.08.2021, at 12:16, Ahmad Fatoum <[email protected]> wrote:
>
> [...]
>
>> If it interests you, I described[2] my CAAM+ubifs+fscrypt use case in the
>> discussion thread on my fscrypt-trusted-keys v1. Jan, a colleague of mine, held a
>> talk[3] on the different solutions for authenticated and encrypted storage, which
>> you may want to check out.
>>
>> I'd really appreciate feedback here on the the CAAM parts of this series, so this can
>> eventually go mainline.
>
> Since you mention the fscrypt trusted-keys use case:
>
> I noticed that the key length for trusted-keys is limited to
> 256 - 1024bit keys. fscrypt does however also support keys
> with e.g. 128bit keys (AES-128-CBC-ESSIV, AES-128-CTS-CBC).
> AFAIK, CAAM and TEE key blobs would also support key lengths outside the 256 - 1024bit range.
>
> Wouldn’t it make sense to align the supported key lengths?
> I.e. extend the range of supported key lengths for trusted keys.
> Or is there a specific reason why key lengths below 256bit are
> not supported by trusted-keys?
No idea. I would suggest staying clear about arguing in its favor though
until CAAM and DCP are merged. My parallel fscrypt endeavors seem to have
only diverted maintainer attention. ;-)
Cheers,
Ahmad
>
> Cheers,
> David
>
>
>
--
Pengutronix e.K. | |
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31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
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On Fri, Aug 20, 2021 at 9:20 AM Ahmad Fatoum <[email protected]> wrote:
>
> Hello Tim,
>
> On 20.08.21 17:39, Tim Harvey wrote:
> > On Wed, Jul 21, 2021 at 9:49 AM Ahmad Fatoum <[email protected]> wrote:
> >>
> >> Series applies on top of
> >> https://lore.kernel.org/linux-integrity/[email protected]/T/#u
> >>
> >> v2 -> v3:
> >> - Split off first Kconfig preparation patch. It fixes a regression,
> >> so sent that out, so it can be applied separately (Sumit)
> >> - Split off second key import patch. I'll send that out separately
> >> as it's a development aid and not required within the CAAM series
> >> - add MAINTAINERS entry
> >>
> >> v1 -> v2:
> >> - Added new commit to make trusted key Kconfig option independent
> >> of TPM and added new Kconfig file for trusted keys
> >> - Add new commit for importing existing key material
> >> - Allow users to force use of kernel RNG (Jarkko)
> >> - Enforce maximum keymod size (Horia)
> >> - Use append_seq_(in|out)_ptr_intlen instead of append_seq_(in|out)_ptr
> >> (Horia)
> >> - Make blobifier handle private to CAAM glue code file (Horia)
> >> - Extend trusted keys documentation for CAAM
> >> - Rebased and updated original cover letter:
> >>
> >> The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
> >> built into many newer i.MX and QorIQ SoCs by NXP.
> >>
> >> Its blob mechanism can AES encrypt/decrypt user data using a unique
> >> never-disclosed device-specific key.
> >>
> >> There has been multiple discussions on how to represent this within the kernel:
> >>
> >> The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
> >> built into many newer i.MX and QorIQ SoCs by NXP.
> >>
> >> Its blob mechanism can AES encrypt/decrypt user data using a unique
> >> never-disclosed device-specific key. There has been multiple
> >> discussions on how to represent this within the kernel:
> >>
> >> - [RFC] crypto: caam - add red blobifier
> >> Steffen implemented[1] a PoC sysfs driver to start a discussion on how to
> >> best integrate the blob mechanism.
> >> Mimi suggested that it could be used to implement trusted keys.
> >> Trusted keys back then were a TPM-only feature.
> >>
> >> - security/keys/secure_key: Adds the secure key support based on CAAM.
> >> Udit added[2] a new "secure" key type with the CAAM as backend. The key
> >> material stays within the kernel only.
> >> Mimi and James agreed that this needs a generic interface, not specific
> >> to CAAM. Mimi suggested trusted keys. Jan noted that this could serve as
> >> basis for TEE-backed keys.
> >>
> >> - [RFC] drivers: crypto: caam: key: Add caam_tk key type
> >> Franck added[3] a new "caam_tk" key type based on Udit's work. This time
> >> it uses CAAM "black blobs" instead of "red blobs", so key material stays
> >> within the CAAM and isn't exposed to kernel in plaintext.
> >> James voiced the opinion that there should be just one user-facing generic
> >> wrap/unwrap key type with multiple possible handlers.
> >> David suggested trusted keys.
> >>
> >> - Introduce TEE based Trusted Keys support
> >> Sumit reworked[4] trusted keys to support multiple possible backends with
> >> one chosen at boot time and added a new TEE backend along with TPM.
> >> This now sits in Jarkko's master branch to be sent out for v5.13
> >>
> >> This patch series builds on top of Sumit's rework to have the CAAM as yet another
> >> trusted key backend.
> >>
> >> The CAAM bits are based on Steffen's initial patch from 2015. His work had been
> >> used in the field for some years now, so I preferred not to deviate too much from it.
> >>
> >> This series has been tested with dmcrypt[5] on an i.MX6DL.
> >>
> >> Looking forward to your feedback.
> >>
> >> Cheers,
> >> Ahmad
> >>
> >> [1]: https://lore.kernel.org/linux-crypto/[email protected]/
> >> [2]: https://lore.kernel.org/linux-integrity/[email protected]/
> >> [3]: https://lore.kernel.org/lkml/[email protected]/
> >> [4]: https://lore.kernel.org/lkml/[email protected]/
> >> [5]: https://lore.kernel.org/linux-integrity/[email protected]/
> >>
> >> ---
> >> To: Jarkko Sakkinen <[email protected]>
> >> To: "Horia Geantă" <[email protected]>
> >> To: Mimi Zohar <[email protected]>
> >> To: Aymen Sghaier <[email protected]>
> >> To: Herbert Xu <[email protected]>
> >> To: "David S. Miller" <[email protected]>
> >> To: James Bottomley <[email protected]>
> >> Cc: David Howells <[email protected]>
> >> Cc: James Morris <[email protected]>
> >> Cc: "Serge E. Hallyn" <[email protected]>
> >> Cc: Steffen Trumtrar <[email protected]>
> >> Cc: Udit Agarwal <[email protected]>
> >> Cc: Jan Luebbe <[email protected]>
> >> Cc: David Gstir <[email protected]>
> >> Cc: Eric Biggers <[email protected]>
> >> Cc: Richard Weinberger <[email protected]>
> >> Cc: Franck LENORMAND <[email protected]>
> >> Cc: Sumit Garg <[email protected]>
> >> Cc: [email protected]
> >> Cc: [email protected]
> >> Cc: [email protected]
> >> Cc: [email protected]
> >> Cc: [email protected]
> >>
> >> Ahmad Fatoum (4):
> >> KEYS: trusted: allow users to use kernel RNG for key material
> >> KEYS: trusted: allow trust sources to use kernel RNG for key material
> >> crypto: caam - add in-kernel interface for blob generator
> >> KEYS: trusted: Introduce support for NXP CAAM-based trusted keys
> >>
> >> Documentation/admin-guide/kernel-parameters.txt | 8 +-
> >> Documentation/security/keys/trusted-encrypted.rst | 60 +++-
> >> MAINTAINERS | 9 +-
> >> drivers/crypto/caam/Kconfig | 3 +-
> >> drivers/crypto/caam/Makefile | 1 +-
> >> drivers/crypto/caam/blob_gen.c | 230 +++++++++++++++-
> >> include/keys/trusted-type.h | 2 +-
> >> include/keys/trusted_caam.h | 11 +-
> >> include/soc/fsl/caam-blob.h | 56 ++++-
> >> security/keys/trusted-keys/Kconfig | 11 +-
> >> security/keys/trusted-keys/Makefile | 2 +-
> >> security/keys/trusted-keys/trusted_caam.c | 74 +++++-
> >> security/keys/trusted-keys/trusted_core.c | 23 +-
> >> 13 files changed, 477 insertions(+), 13 deletions(-)
> >> create mode 100644 drivers/crypto/caam/blob_gen.c
> >> create mode 100644 include/keys/trusted_caam.h
> >> create mode 100644 include/soc/fsl/caam-blob.h
> >> create mode 100644 security/keys/trusted-keys/trusted_caam.c
> >>
> >> base-commit: 97408d81ed533b953326c580ff2c3f1948b3fcee
> >> --
> >> git-series 0.9.1
> >
> > Ahmad,
> >
> > Thanks for your work!
> >
> > I've been asked to integrate the capability of using CAAM to
> > blob/deblob data to an older 5.4 kernel such as NXP's downstream
> > vendor kernel does [1] and I'm trying to understand how your series
> > works. I'm not at all familiar with the Linux Key Management API's or
> > trusted keys. Can you provide an example of how this can be used for
> > such a thing?
>
> Here's an example with dm-crypt:
>
> https://lore.kernel.org/linux-integrity/[email protected]/
>
> dm-crypt is a bit special at the moment, because it has direct support for
> trusted keys. For interfacing with other parts of the kernel like ecryptfs
> or EVM, you have to create encrypted keys rooted to the trusted keys and use
> those. The kernel documentation has an example:
>
> https://www.kernel.org/doc/html/v5.13/security/keys/trusted-encrypted.html
>
> If you backport this series, you can include the typo fix spotted by David.
>
> I'll send out a revised series, but given that a regression fix I want to
> rebase on hasn't been picked up for 3 weeks now, I am not in a hurry.
>
Ahmad,
Thanks for the reference.
I'm still trying to understand the keyctl integration with caam. For
the 'data' param to keyctl you are using tings like 'new <len>' and
'load <data>'. Where are these 'commands' identified?
I may still be missing something. I'm using 4.14-rc6 with your series
and seeing the following:
# cat /proc/cmdline
trusted.source=caam
# keyctl add trusted mykey 'new 32' @s)# create new trusted key named
'mykey' of 32 bytes in the session keyring
480104283
# keyctl print 480104283 # dump the key
keyctl_read_alloc: Unknown error 126
^^^ not clear what this is
Best regards,
Tim
On Fri, Aug 20, 2021 at 1:36 PM Ahmad Fatoum <[email protected]> wrote:
>
> On 20.08.21 22:20, Tim Harvey wrote:
> > On Fri, Aug 20, 2021 at 9:20 AM Ahmad Fatoum <[email protected]> wrote:
> >> On 20.08.21 17:39, Tim Harvey wrote:
> >>> Thanks for your work!
> >>>
> >>> I've been asked to integrate the capability of using CAAM to
> >>> blob/deblob data to an older 5.4 kernel such as NXP's downstream
> >>> vendor kernel does [1] and I'm trying to understand how your series
> >>> works. I'm not at all familiar with the Linux Key Management API's or
> >>> trusted keys. Can you provide an example of how this can be used for
> >>> such a thing?
> >>
> >> Here's an example with dm-crypt:
> >>
> >> https://lore.kernel.org/linux-integrity/[email protected]/
> >>
> >> dm-crypt is a bit special at the moment, because it has direct support for
> >> trusted keys. For interfacing with other parts of the kernel like ecryptfs
> >> or EVM, you have to create encrypted keys rooted to the trusted keys and use
> >> those. The kernel documentation has an example:
> >>
> >> https://www.kernel.org/doc/html/v5.13/security/keys/trusted-encrypted.html
> >>
> >> If you backport this series, you can include the typo fix spotted by David.
> >>
> >> I'll send out a revised series, but given that a regression fix I want to
> >> rebase on hasn't been picked up for 3 weeks now, I am not in a hurry.
> >>
> > Thanks for the reference.
> >
> > I'm still trying to understand the keyctl integration with caam. For
> > the 'data' param to keyctl you are using tings like 'new <len>' and
> > 'load <data>'. Where are these 'commands' identified?
>
> Search for match_table_t in security/keys/trusted-keys/trusted_core.c
>
> > I may still be missing something. I'm using 4.14-rc6 with your series
> > and seeing the following:
>
> That's an odd version to backport stuff to..
>
> > # cat /proc/cmdline
> > trusted.source=caam
> > # keyctl add trusted mykey 'new 32' @s)# create new trusted key named
> > 'mykey' of 32 bytes in the session keyring
> > 480104283
> > # keyctl print 480104283 # dump the key
> > keyctl_read_alloc: Unknown error 126
> > ^^^ not clear what this is
>
> Not sure what returns -ENOKEY for you. I haven't been using trusted
> keys on v4.14, but you can try tracing the keyctl syscall.
yikes... that would be painful. I typo'd and meant 5.14-rc6 :) I'm
working with mainline first to make sure I understand everything. If I
backport this it would be to 5.4 but that looks to be extremely
painful. It looks like there was a lot of activity around trusted keys
in 5.13.
It works for a user keyring but not a session keyring... does that
explain anything?
# keyctl add trusted mykey 'new 32' @u
941210782
# keyctl print 941210782
83b7845cb45216496aead9ee2c6a406f587d64aad47bddc539d8947a247e618798d9306b36398b5dc2722a4c3f220a3a763ee175f6bd64758fdd49ca4db597e8ce328121b60edbba9b8d8d55056be896
# keyctl add trusted mykey 'new 32' @s
310571960
# keyctl print 310571960
keyctl_read_alloc: Unknown error 126
Sorry, I'm still trying to wrap my head around the differences in
keyrings and trusted vs user keys.
Tim
Hello Tim,
On 20.08.21 23:19, Tim Harvey wrote:
> On Fri, Aug 20, 2021 at 1:36 PM Ahmad Fatoum <[email protected]> wrote:
>>
>> On 20.08.21 22:20, Tim Harvey wrote:
>>> On Fri, Aug 20, 2021 at 9:20 AM Ahmad Fatoum <[email protected]> wrote:
>>>> On 20.08.21 17:39, Tim Harvey wrote:
>>>>> Thanks for your work!
>>>>>
>>>>> I've been asked to integrate the capability of using CAAM to
>>>>> blob/deblob data to an older 5.4 kernel such as NXP's downstream
>>>>> vendor kernel does [1] and I'm trying to understand how your series
>>>>> works. I'm not at all familiar with the Linux Key Management API's or
>>>>> trusted keys. Can you provide an example of how this can be used for
>>>>> such a thing?
>>>>
>>>> Here's an example with dm-crypt:
>>>>
>>>> https://lore.kernel.org/linux-integrity/[email protected]/
>>>>
>>>> dm-crypt is a bit special at the moment, because it has direct support for
>>>> trusted keys. For interfacing with other parts of the kernel like ecryptfs
>>>> or EVM, you have to create encrypted keys rooted to the trusted keys and use
>>>> those. The kernel documentation has an example:
>>>>
>>>> https://www.kernel.org/doc/html/v5.13/security/keys/trusted-encrypted.html
>>>>
>>>> If you backport this series, you can include the typo fix spotted by David.
>>>>
>>>> I'll send out a revised series, but given that a regression fix I want to
>>>> rebase on hasn't been picked up for 3 weeks now, I am not in a hurry.
>>>>
>>> Thanks for the reference.
>>>
>>> I'm still trying to understand the keyctl integration with caam. For
>>> the 'data' param to keyctl you are using tings like 'new <len>' and
>>> 'load <data>'. Where are these 'commands' identified?
>>
>> Search for match_table_t in security/keys/trusted-keys/trusted_core.c
>>
>>> I may still be missing something. I'm using 4.14-rc6 with your series
>>> and seeing the following:
>>
>> That's an odd version to backport stuff to..
>>
>>> # cat /proc/cmdline
>>> trusted.source=caam
>>> # keyctl add trusted mykey 'new 32' @s)# create new trusted key named
>>> 'mykey' of 32 bytes in the session keyring
>>> 480104283
>>> # keyctl print 480104283 # dump the key
>>> keyctl_read_alloc: Unknown error 126
>>> ^^^ not clear what this is
>>
>> Not sure what returns -ENOKEY for you. I haven't been using trusted
>> keys on v4.14, but you can try tracing the keyctl syscall.
>
> yikes... that would be painful. I typo'd and meant 5.14-rc6 :)
^^
> I'm working with mainline first to make sure I understand everything. If I
> backport this it would be to 5.4 but that looks to be extremely
> painful. It looks like there was a lot of activity around trusted keys
> in 5.13.
Ye. It used to be limited to TPM before that.
> It works for a user keyring but not a session keyring... does that
> explain anything?
> # keyctl add trusted mykey 'new 32' @u
> 941210782
> # keyctl print 941210782
> 83b7845cb45216496aead9ee2c6a406f587d64aad47bddc539d8947a247e618798d9306b36398b5dc2722a4c3f220a3a763ee175f6bd64758fdd49ca4db597e8ce328121b60edbba9b8d8d55056be896
> # keyctl add trusted mykey 'new 32' @s
> 310571960
> # keyctl print 310571960
> keyctl_read_alloc: Unknown error 126
Both sequences work for me.
My getty is started by systemd. I think systemd allocates a new session
keyring for the getty that's inherited by the shell and the commands I run
it in. If you don't do that, each command will get its own session key.
> Sorry, I'm still trying to wrap my head around the differences in
> keyrings and trusted vs user keys.
No problem. HTH.
Cheers,
Ahmad
>
> Tim
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
On Mon, Aug 23, 2021 at 6:29 AM Ahmad Fatoum <[email protected]> wrote:
>
> Hello Tim,
>
> On 20.08.21 23:19, Tim Harvey wrote:
> > On Fri, Aug 20, 2021 at 1:36 PM Ahmad Fatoum <[email protected]> wrote:
> >>
> >> On 20.08.21 22:20, Tim Harvey wrote:
> >>> On Fri, Aug 20, 2021 at 9:20 AM Ahmad Fatoum <[email protected]> wrote:
> >>>> On 20.08.21 17:39, Tim Harvey wrote:
> >>>>> Thanks for your work!
> >>>>>
> >>>>> I've been asked to integrate the capability of using CAAM to
> >>>>> blob/deblob data to an older 5.4 kernel such as NXP's downstream
> >>>>> vendor kernel does [1] and I'm trying to understand how your series
> >>>>> works. I'm not at all familiar with the Linux Key Management API's or
> >>>>> trusted keys. Can you provide an example of how this can be used for
> >>>>> such a thing?
> >>>>
> >>>> Here's an example with dm-crypt:
> >>>>
> >>>> https://lore.kernel.org/linux-integrity/[email protected]/
> >>>>
> >>>> dm-crypt is a bit special at the moment, because it has direct support for
> >>>> trusted keys. For interfacing with other parts of the kernel like ecryptfs
> >>>> or EVM, you have to create encrypted keys rooted to the trusted keys and use
> >>>> those. The kernel documentation has an example:
> >>>>
> >>>> https://www.kernel.org/doc/html/v5.13/security/keys/trusted-encrypted.html
> >>>>
> >>>> If you backport this series, you can include the typo fix spotted by David.
> >>>>
> >>>> I'll send out a revised series, but given that a regression fix I want to
> >>>> rebase on hasn't been picked up for 3 weeks now, I am not in a hurry.
> >>>>
> >>> Thanks for the reference.
> >>>
> >>> I'm still trying to understand the keyctl integration with caam. For
> >>> the 'data' param to keyctl you are using tings like 'new <len>' and
> >>> 'load <data>'. Where are these 'commands' identified?
> >>
> >> Search for match_table_t in security/keys/trusted-keys/trusted_core.c
> >>
> >>> I may still be missing something. I'm using 4.14-rc6 with your series
> >>> and seeing the following:
> >>
> >> That's an odd version to backport stuff to..
> >>
> >>> # cat /proc/cmdline
> >>> trusted.source=caam
> >>> # keyctl add trusted mykey 'new 32' @s)# create new trusted key named
> >>> 'mykey' of 32 bytes in the session keyring
> >>> 480104283
> >>> # keyctl print 480104283 # dump the key
> >>> keyctl_read_alloc: Unknown error 126
> >>> ^^^ not clear what this is
> >>
> >> Not sure what returns -ENOKEY for you. I haven't been using trusted
> >> keys on v4.14, but you can try tracing the keyctl syscall.
> >
> > yikes... that would be painful. I typo'd and meant 5.14-rc6 :)
>
> ^^
>
> > I'm working with mainline first to make sure I understand everything. If I
> > backport this it would be to 5.4 but that looks to be extremely
> > painful. It looks like there was a lot of activity around trusted keys
> > in 5.13.
>
> Ye. It used to be limited to TPM before that.
>
> > It works for a user keyring but not a session keyring... does that
> > explain anything?
> > # keyctl add trusted mykey 'new 32' @u
> > 941210782
> > # keyctl print 941210782
> > 83b7845cb45216496aead9ee2c6a406f587d64aad47bddc539d8947a247e618798d9306b36398b5dc2722a4c3f220a3a763ee175f6bd64758fdd49ca4db597e8ce328121b60edbba9b8d8d55056be896
> > # keyctl add trusted mykey 'new 32' @s
> > 310571960
> > # keyctl print 310571960
> > keyctl_read_alloc: Unknown error 126
>
> Both sequences work for me.
>
> My getty is started by systemd. I think systemd allocates a new session
> keyring for the getty that's inherited by the shell and the commands I run
> it in. If you don't do that, each command will get its own session key.
>
> > Sorry, I'm still trying to wrap my head around the differences in
> > keyrings and trusted vs user keys.
>
> No problem. HTH.
Ahmad,
Ok that explains it - my testing is using a very basic buildroot
ramdisk rootfs. If I do a 'keyctl new_session' first I can use the
system keyring fine as well.
Thanks - hoping to see this merged soon!
Tim
On 23.08.21 19:50, Tim Harvey wrote:
> On Mon, Aug 23, 2021 at 6:29 AM Ahmad Fatoum <[email protected]> wrote:
>> On 20.08.21 23:19, Tim Harvey wrote:
>>> On Fri, Aug 20, 2021 at 1:36 PM Ahmad Fatoum <[email protected]> wrote:
>>>> On 20.08.21 22:20, Tim Harvey wrote:
>>> It works for a user keyring but not a session keyring... does that
>>> explain anything?
>>> # keyctl add trusted mykey 'new 32' @u
>>> 941210782
>>> # keyctl print 941210782
>>> 83b7845cb45216496aead9ee2c6a406f587d64aad47bddc539d8947a247e618798d9306b36398b5dc2722a4c3f220a3a763ee175f6bd64758fdd49ca4db597e8ce328121b60edbba9b8d8d55056be896
>>> # keyctl add trusted mykey 'new 32' @s
>>> 310571960
>>> # keyctl print 310571960
>>> keyctl_read_alloc: Unknown error 126
>>
>> Both sequences work for me.
>>
>> My getty is started by systemd. I think systemd allocates a new session
>> keyring for the getty that's inherited by the shell and the commands I run
>> it in. If you don't do that, each command will get its own session key.
>>
>>> Sorry, I'm still trying to wrap my head around the differences in
>>> keyrings and trusted vs user keys.
>>
>> No problem. HTH.
>
> Ahmad,
>
> Ok that explains it - my testing is using a very basic buildroot
> ramdisk rootfs. If I do a 'keyctl new_session' first I can use the
> system keyring fine as well.
Great. Does this mean I can get your Tested-by: ? :)
> Thanks - hoping to see this merged soon!
You and me both.
Cheers,
Ahmad
>
> Tim
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
On Tue, Aug 24, 2021 at 12:33 AM Ahmad Fatoum <[email protected]> wrote:
>
> On 23.08.21 19:50, Tim Harvey wrote:
> > On Mon, Aug 23, 2021 at 6:29 AM Ahmad Fatoum <[email protected]> wrote:
> >> On 20.08.21 23:19, Tim Harvey wrote:
> >>> On Fri, Aug 20, 2021 at 1:36 PM Ahmad Fatoum <[email protected]> wrote:
> >>>> On 20.08.21 22:20, Tim Harvey wrote:
> >>> It works for a user keyring but not a session keyring... does that
> >>> explain anything?
> >>> # keyctl add trusted mykey 'new 32' @u
> >>> 941210782
> >>> # keyctl print 941210782
> >>> 83b7845cb45216496aead9ee2c6a406f587d64aad47bddc539d8947a247e618798d9306b36398b5dc2722a4c3f220a3a763ee175f6bd64758fdd49ca4db597e8ce328121b60edbba9b8d8d55056be896
> >>> # keyctl add trusted mykey 'new 32' @s
> >>> 310571960
> >>> # keyctl print 310571960
> >>> keyctl_read_alloc: Unknown error 126
> >>
> >> Both sequences work for me.
> >>
> >> My getty is started by systemd. I think systemd allocates a new session
> >> keyring for the getty that's inherited by the shell and the commands I run
> >> it in. If you don't do that, each command will get its own session key.
> >>
> >>> Sorry, I'm still trying to wrap my head around the differences in
> >>> keyrings and trusted vs user keys.
> >>
> >> No problem. HTH.
> >
> > Ahmad,
> >
> > Ok that explains it - my testing is using a very basic buildroot
> > ramdisk rootfs. If I do a 'keyctl new_session' first I can use the
> > system keyring fine as well.
>
> Great. Does this mean I can get your Tested-by: ? :)
>
Absolutely,
For the series:
I tested this series on top of v5.14.rc-7 on a Gateworks
imx8mm-venice-gw73xx board with kernel param trusted.source=caam and
keyutils-1.6:
# keyctl new_session
22544757
# keyctl add trusted mykey 'new 32' @s
160701809
# keyctl print 160701809
990e03aa4515aee420eede17e26a58d0c5568c8bd2c9c2ee2f22a0583181d20d4f65cf9cb1f944a3cc92c0e3184a44a29a7e511f0a55a6af11a70ac2b2924514002475e73ae09820042896b9ee00a5ec
Tested-By: Tim Harvey <[email protected]>
One more question: I've got a user that wants to blob/deblob generic
data. They can use the caam_encap_blob/caam_decap_blob functions in
kernel code but could you give me a suggestion for how they could use
this in:
a) userspace code (using the keyctl syscall I assume)
b) userspace cmdline (via keyutils I assume)
Many thanks,
Tim
On 24.08.21 17:23, Tim Harvey wrote:
> On Tue, Aug 24, 2021 at 12:33 AM Ahmad Fatoum <[email protected]> wrote:
>>
>> On 23.08.21 19:50, Tim Harvey wrote:
>>> On Mon, Aug 23, 2021 at 6:29 AM Ahmad Fatoum <[email protected]> wrote:
>>>> On 20.08.21 23:19, Tim Harvey wrote:
>>>>> On Fri, Aug 20, 2021 at 1:36 PM Ahmad Fatoum <[email protected]> wrote:
>>>>>> On 20.08.21 22:20, Tim Harvey wrote:
>>>>> It works for a user keyring but not a session keyring... does that
>>>>> explain anything?
>>>>> # keyctl add trusted mykey 'new 32' @u
>>>>> 941210782
>>>>> # keyctl print 941210782
>>>>> 83b7845cb45216496aead9ee2c6a406f587d64aad47bddc539d8947a247e618798d9306b36398b5dc2722a4c3f220a3a763ee175f6bd64758fdd49ca4db597e8ce328121b60edbba9b8d8d55056be896
>>>>> # keyctl add trusted mykey 'new 32' @s
>>>>> 310571960
>>>>> # keyctl print 310571960
>>>>> keyctl_read_alloc: Unknown error 126
>>>>
>>>> Both sequences work for me.
>>>>
>>>> My getty is started by systemd. I think systemd allocates a new session
>>>> keyring for the getty that's inherited by the shell and the commands I run
>>>> it in. If you don't do that, each command will get its own session key.
>>>>
>>>>> Sorry, I'm still trying to wrap my head around the differences in
>>>>> keyrings and trusted vs user keys.
>>>>
>>>> No problem. HTH.
>>>
>>> Ahmad,
>>>
>>> Ok that explains it - my testing is using a very basic buildroot
>>> ramdisk rootfs. If I do a 'keyctl new_session' first I can use the
>>> system keyring fine as well.
>>
>> Great. Does this mean I can get your Tested-by: ? :)
>>
>
> Absolutely,
>
> For the series:
>
> I tested this series on top of v5.14.rc-7 on a Gateworks
> imx8mm-venice-gw73xx board with kernel param trusted.source=caam and
> keyutils-1.6:
> # keyctl new_session
> 22544757
> # keyctl add trusted mykey 'new 32' @s
> 160701809
> # keyctl print 160701809
> 990e03aa4515aee420eede17e26a58d0c5568c8bd2c9c2ee2f22a0583181d20d4f65cf9cb1f944a3cc92c0e3184a44a29a7e511f0a55a6af11a70ac2b2924514002475e73ae09820042896b9ee00a5ec
>
> Tested-By: Tim Harvey <[email protected]>
Thanks. I'll apply it to the whole series then.
> One more question: I've got a user that wants to blob/deblob generic
> data. They can use the caam_encap_blob/caam_decap_blob functions in
> kernel code but could you give me a suggestion for how they could use
> this in:
> a) userspace code (using the keyctl syscall I assume)
> b) userspace cmdline (via keyutils I assume)
Trusted keys aren't disclosed to userspace in plain text, only in sealed
form (bar vulnerabilities of course).
Cheers,
Ahmad
>
> Many thanks,
>
> Tim
>
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