In order to verify the OS kernel on PowerNV systems, secure boot requires
X.509 certificates trusted by the platform. These are stored in secure
variables controlled by OPAL, called OPAL secure variables. In order to
enable users to manage the keys, the secure variables need to be exposed
to userspace.
OPAL provides the runtime services for the kernel to be able to access the
secure variables[1]. This patchset defines the kernel interface for the
OPAL APIs. These APIs are used by the hooks, which load these variables
to the keyring and expose them to the userspace for reading/writing.
The previous version[2] of the patchset added support only for the sysfs
interface. This patch adds two more patches that involves loading of
the firmware trusted keys to the kernel keyring.
Overall, this patchset adds the following support:
* expose secure variables to the kernel via OPAL Runtime API interface
* expose secure variables to the userspace via kernel sysfs interface
* load kernel verification and revocation keys to .platform and
.blacklist keyring respectively.
The secure variables can be read/written using simple linux utilities
cat/hexdump.
For example:
Path to the secure variables is:
/sys/firmware/secvar/vars
Each secure variable is listed as directory.
$ ls -l
total 0
drwxr-xr-x. 2 root root 0 Aug 20 21:20 db
drwxr-xr-x. 2 root root 0 Aug 20 21:20 KEK
drwxr-xr-x. 2 root root 0 Aug 20 21:20 PK
The attributes of each of the secure variables are(for example: PK):
[db]$ ls -l
total 0
-r--r--r--. 1 root root 4096 Oct 1 15:10 data
-r--r--r--. 1 root root 65536 Oct 1 15:10 size
--w-------. 1 root root 4096 Oct 1 15:12 update
The "data" is used to read the existing variable value using hexdump. The
data is stored in ESL format.
The "update" is used to write a new value using cat. The update is
to be submitted as AUTH file.
[1] Depends on skiboot OPAL API changes which removes metadata from
the API. https://lists.ozlabs.org/pipermail/skiboot/2019-September/015203.html.
[2] https://lkml.org/lkml/2019/6/13/1644
Changelog:
v5:
* rebased to v5.4-rc3
* includes Oliver's feedbacks
* changed OPAL API as platform driver
* sysfs are made default enabled and dependent on PPC_SECURE_BOOT
* fixed code specific changes in both OPAL API and sysfs
* reading size of the "data" and "update" file from device-tree.
* fixed sysfs documentation to also reflect the data and update file
size interpretation
* This patchset is no more dependent on ima-arch/blacklist patchset
v4:
* rebased to v5.4-rc1
* uses __BIN_ATTR_WO macro to create binary attribute as suggested by
Greg
* removed email id from the file header
* renamed argument keysize to keybufsize in get_next() function
* updated default binary file sizes to 0, as firmware handles checking
against the maximum size
* fixed minor formatting issues in Patch 4/4
* added Greg's and Mimi's Reviewed-by and Ack-by
v3:
* includes Greg's feedbacks:
* fixes in Patch 2/4
* updates the Documentation.
* fixes code feedbacks
* adds SYSFS Kconfig dependency for SECVAR_SYSFS
* fixes mixed tabs and spaces
* removes "name" attribute for each of the variable name based
directories
* fixes using __ATTR_RO() and __BIN_ATTR_RO() and statics and const
* fixes the racing issue by using kobj_type default groups. Also,
fixes the kobject leakage.
* removes extra print messages
* updates patch description for Patch 3/4
* removes file name from Patch 4/4 file header comment and removed
def_bool y from the LOAD_PPC_KEYS Kconfig
* includes Oliver's feedbacks:
* fixes Patch 1/2
* moves OPAL API wrappers after opal_nx_proc_init(), fixed the
naming, types and removed extern.
* fixes spaces
* renames get_variable() to get(), get_next_variable() to get_next()
and set_variable() to set()
* removed get_secvar_ops() and defined secvar_ops as global
* fixes consts and statics
* removes generic secvar_init() and defined platform specific
opal_secar_init()
* updates opal_secvar_supported() to check for secvar support even
before checking the OPAL APIs support and also fixed the error codes.
* addes function that converts OPAL return codes to linux errno
* moves secvar check support in the opal_secvar_init() and defined its
prototype in opal.h
* fixes Patch 2/2
* fixes static/const
* defines macro for max name size
* replaces OPAL error codes with linux errno and also updated error
handling
* moves secvar support check before creating sysfs kobjects in
secvar_sysfs_init()
* fixes spaces
v2:
* removes complete efi-sms from the sysfs implementation and is simplified
* includes Greg's and Oliver's feedbacks:
* adds sysfs documentation
* moves sysfs code to arch/powerpc
* other code related feedbacks.
* adds two new patches to load keys to .platform and .blacklist keyring.
These patches are added to this series as they are also dependent on
OPAL APIs.
Nayna Jain (4):
powerpc/powernv: Add OPAL API interface to access secure variable
powerpc: expose secure variables to userspace via sysfs
x86/efi: move common keyring handler functions to new file
powerpc: load firmware trusted keys/hashes into kernel keyring
Documentation/ABI/testing/sysfs-secvar | 39 +++
arch/powerpc/Kconfig | 12 +
arch/powerpc/include/asm/opal-api.h | 5 +-
arch/powerpc/include/asm/opal.h | 7 +
arch/powerpc/include/asm/secvar.h | 35 +++
arch/powerpc/kernel/Makefile | 3 +-
arch/powerpc/kernel/secvar-ops.c | 16 ++
arch/powerpc/kernel/secvar-sysfs.c | 228 ++++++++++++++++++
arch/powerpc/platforms/powernv/Makefile | 2 +-
arch/powerpc/platforms/powernv/opal-call.c | 3 +
arch/powerpc/platforms/powernv/opal-secvar.c | 140 +++++++++++
arch/powerpc/platforms/powernv/opal.c | 3 +
security/integrity/Kconfig | 8 +
security/integrity/Makefile | 7 +-
.../platform_certs/keyring_handler.c | 80 ++++++
.../platform_certs/keyring_handler.h | 32 +++
.../integrity/platform_certs/load_powerpc.c | 86 +++++++
security/integrity/platform_certs/load_uefi.c | 67 +----
18 files changed, 702 insertions(+), 71 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-secvar
create mode 100644 arch/powerpc/include/asm/secvar.h
create mode 100644 arch/powerpc/kernel/secvar-ops.c
create mode 100644 arch/powerpc/kernel/secvar-sysfs.c
create mode 100644 arch/powerpc/platforms/powernv/opal-secvar.c
create mode 100644 security/integrity/platform_certs/keyring_handler.c
create mode 100644 security/integrity/platform_certs/keyring_handler.h
create mode 100644 security/integrity/platform_certs/load_powerpc.c
--
2.20.1
The X.509 certificates trusted by the platform and required to secure boot
the OS kernel are wrapped in secure variables, which are controlled by
OPAL.
This patch adds firmware/kernel interface to read and write OPAL secure
variables based on the unique key.
This support can be enabled using CONFIG_OPAL_SECVAR.
Signed-off-by: Claudio Carvalho <[email protected]>
Signed-off-by: Nayna Jain <[email protected]>
---
arch/powerpc/include/asm/opal-api.h | 5 +-
arch/powerpc/include/asm/opal.h | 7 +
arch/powerpc/include/asm/secvar.h | 35 +++++
arch/powerpc/kernel/Makefile | 2 +-
arch/powerpc/kernel/secvar-ops.c | 16 +++
arch/powerpc/platforms/powernv/Makefile | 2 +-
arch/powerpc/platforms/powernv/opal-call.c | 3 +
arch/powerpc/platforms/powernv/opal-secvar.c | 140 +++++++++++++++++++
arch/powerpc/platforms/powernv/opal.c | 3 +
9 files changed, 210 insertions(+), 3 deletions(-)
create mode 100644 arch/powerpc/include/asm/secvar.h
create mode 100644 arch/powerpc/kernel/secvar-ops.c
create mode 100644 arch/powerpc/platforms/powernv/opal-secvar.c
diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 378e3997845a..c1f25a760eb1 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -211,7 +211,10 @@
#define OPAL_MPIPL_UPDATE 173
#define OPAL_MPIPL_REGISTER_TAG 174
#define OPAL_MPIPL_QUERY_TAG 175
-#define OPAL_LAST 175
+#define OPAL_SECVAR_GET 176
+#define OPAL_SECVAR_GET_NEXT 177
+#define OPAL_SECVAR_ENQUEUE_UPDATE 178
+#define OPAL_LAST 178
#define QUIESCE_HOLD 1 /* Spin all calls at entry */
#define QUIESCE_REJECT 2 /* Fail all calls with OPAL_BUSY */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index a0cf8fba4d12..9986ac34b8e2 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -298,6 +298,13 @@ int opal_sensor_group_clear(u32 group_hndl, int token);
int opal_sensor_group_enable(u32 group_hndl, int token, bool enable);
int opal_nx_coproc_init(uint32_t chip_id, uint32_t ct);
+int opal_secvar_get(const char *key, uint64_t key_len, u8 *data,
+ uint64_t *data_size);
+int opal_secvar_get_next(const char *key, uint64_t *key_len,
+ uint64_t key_buf_size);
+int opal_secvar_enqueue_update(const char *key, uint64_t key_len, u8 *data,
+ uint64_t data_size);
+
s64 opal_mpipl_update(enum opal_mpipl_ops op, u64 src, u64 dest, u64 size);
s64 opal_mpipl_register_tag(enum opal_mpipl_tags tag, u64 addr);
s64 opal_mpipl_query_tag(enum opal_mpipl_tags tag, u64 *addr);
diff --git a/arch/powerpc/include/asm/secvar.h b/arch/powerpc/include/asm/secvar.h
new file mode 100644
index 000000000000..4cc35b58b986
--- /dev/null
+++ b/arch/powerpc/include/asm/secvar.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ *
+ * PowerPC secure variable operations.
+ */
+#ifndef SECVAR_OPS_H
+#define SECVAR_OPS_H
+
+#include <linux/types.h>
+#include <linux/errno.h>
+
+extern const struct secvar_operations *secvar_ops;
+
+struct secvar_operations {
+ int (*get)(const char *key, uint64_t key_len, u8 *data,
+ uint64_t *data_size);
+ int (*get_next)(const char *key, uint64_t *key_len,
+ uint64_t keybufsize);
+ int (*set)(const char *key, uint64_t key_len, u8 *data,
+ uint64_t data_size);
+};
+
+#ifdef CONFIG_PPC_SECURE_BOOT
+
+extern void set_secvar_ops(const struct secvar_operations *ops);
+
+#else
+
+static inline void set_secvar_ops(const struct secvar_operations *ops) { }
+
+#endif
+
+#endif
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index e8eb2955b7d5..3cf26427334f 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -161,7 +161,7 @@ ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),)
obj-y += ucall.o
endif
-obj-$(CONFIG_PPC_SECURE_BOOT) += secure_boot.o ima_arch.o
+obj-$(CONFIG_PPC_SECURE_BOOT) += secure_boot.o ima_arch.o secvar-ops.o
# Disable GCOV, KCOV & sanitizers in odd or sensitive code
GCOV_PROFILE_prom_init.o := n
diff --git a/arch/powerpc/kernel/secvar-ops.c b/arch/powerpc/kernel/secvar-ops.c
new file mode 100644
index 000000000000..4cfa7dbd8850
--- /dev/null
+++ b/arch/powerpc/kernel/secvar-ops.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ *
+ * This file initializes secvar operations for PowerPC Secureboot
+ */
+
+#include <asm/secvar.h>
+
+const struct secvar_operations *secvar_ops;
+
+void set_secvar_ops(const struct secvar_operations *ops)
+{
+ secvar_ops = ops;
+}
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index a3ac9646119d..f9c4fa99e8b9 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -4,7 +4,7 @@ obj-y += idle.o opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
obj-y += rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
obj-y += opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
obj-y += opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o
-obj-y += ultravisor.o
+obj-y += ultravisor.o opal-secvar.o
obj-$(CONFIG_SMP) += smp.o subcore.o subcore-asm.o
obj-$(CONFIG_FA_DUMP) += opal-fadump.o
diff --git a/arch/powerpc/platforms/powernv/opal-call.c b/arch/powerpc/platforms/powernv/opal-call.c
index a2aa5e433ac8..5cd0f52d258f 100644
--- a/arch/powerpc/platforms/powernv/opal-call.c
+++ b/arch/powerpc/platforms/powernv/opal-call.c
@@ -290,3 +290,6 @@ OPAL_CALL(opal_nx_coproc_init, OPAL_NX_COPROC_INIT);
OPAL_CALL(opal_mpipl_update, OPAL_MPIPL_UPDATE);
OPAL_CALL(opal_mpipl_register_tag, OPAL_MPIPL_REGISTER_TAG);
OPAL_CALL(opal_mpipl_query_tag, OPAL_MPIPL_QUERY_TAG);
+OPAL_CALL(opal_secvar_get, OPAL_SECVAR_GET);
+OPAL_CALL(opal_secvar_get_next, OPAL_SECVAR_GET_NEXT);
+OPAL_CALL(opal_secvar_enqueue_update, OPAL_SECVAR_ENQUEUE_UPDATE);
diff --git a/arch/powerpc/platforms/powernv/opal-secvar.c b/arch/powerpc/platforms/powernv/opal-secvar.c
new file mode 100644
index 000000000000..4cfb282a9feb
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-secvar.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PowerNV code for secure variables
+ *
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Claudio Carvalho
+ * Nayna Jain
+ *
+ * APIs to access secure variables managed by OPAL.
+ */
+
+#define pr_fmt(fmt) "secvar: "fmt
+
+#include <linux/types.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <asm/opal.h>
+#include <asm/secvar.h>
+#include <asm/secure_boot.h>
+
+static int opal_status_to_err(int rc)
+{
+ int err;
+
+ switch (rc) {
+ case OPAL_SUCCESS:
+ err = 0;
+ break;
+ case OPAL_UNSUPPORTED:
+ err = -ENXIO;
+ break;
+ case OPAL_PARAMETER:
+ err = -EINVAL;
+ break;
+ case OPAL_RESOURCE:
+ err = -ENOSPC;
+ break;
+ case OPAL_HARDWARE:
+ err = -EIO;
+ break;
+ case OPAL_NO_MEM:
+ err = -ENOMEM;
+ break;
+ case OPAL_EMPTY:
+ err = -ENOENT;
+ break;
+ case OPAL_PARTIAL:
+ err = -EFBIG;
+ break;
+ default:
+ err = -EINVAL;
+ }
+
+ return err;
+}
+
+static int opal_get_variable(const char *key, uint64_t ksize,
+ u8 *data, uint64_t *dsize)
+{
+ int rc;
+
+ if (!key || !dsize)
+ return -EINVAL;
+
+ *dsize = cpu_to_be64(*dsize);
+
+ rc = opal_secvar_get(key, ksize, data, dsize);
+
+ *dsize = be64_to_cpu(*dsize);
+
+ return opal_status_to_err(rc);
+}
+
+static int opal_get_next_variable(const char *key, uint64_t *keylen,
+ uint64_t keybufsize)
+{
+ int rc;
+
+ if (!key || !keylen)
+ return -EINVAL;
+
+ *keylen = cpu_to_be64(*keylen);
+
+ rc = opal_secvar_get_next(key, keylen, keybufsize);
+
+ *keylen = be64_to_cpu(*keylen);
+
+ return opal_status_to_err(rc);
+}
+
+static int opal_set_variable(const char *key, uint64_t ksize, u8 *data,
+ uint64_t dsize)
+{
+ int rc;
+
+ if (!key || !data)
+ return -EINVAL;
+
+ rc = opal_secvar_enqueue_update(key, ksize, data, dsize);
+
+ return opal_status_to_err(rc);
+}
+
+static const struct secvar_operations opal_secvar_ops = {
+ .get = opal_get_variable,
+ .get_next = opal_get_next_variable,
+ .set = opal_set_variable,
+};
+
+static int opal_secvar_probe(struct platform_device *pdev)
+{
+ if (!opal_check_token(OPAL_SECVAR_GET)
+ || !opal_check_token(OPAL_SECVAR_GET_NEXT)
+ || !opal_check_token(OPAL_SECVAR_ENQUEUE_UPDATE)) {
+ pr_err("OPAL doesn't support secure variables\n");
+ return -ENODEV;
+ }
+
+ set_secvar_ops(&opal_secvar_ops);
+
+ return 0;
+}
+
+static const struct of_device_id opal_secvar_match[] = {
+ { .compatible = "ibm,secvar-v1",},
+ {},
+};
+
+static struct platform_driver opal_secvar_driver = {
+ .driver = {
+ .name = "secvar",
+ .of_match_table = opal_secvar_match,
+ },
+};
+
+static int __init opal_secvar_init(void)
+{
+ return platform_driver_probe(&opal_secvar_driver, opal_secvar_probe);
+}
+device_initcall(opal_secvar_init);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 38e90270280b..8d1e45a8bdc2 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -1002,6 +1002,9 @@ static int __init opal_init(void)
/* Initialise OPAL Power control interface */
opal_power_control_init();
+ /* Initialize OPAL secure variables */
+ opal_pdev_init("ibm,secvar-v1");
+
return 0;
}
machine_subsys_initcall(powernv, opal_init);
--
2.20.1
The handlers to add the keys to the .platform keyring and blacklisted
hashes to the .blacklist keyring is common for both the uefi and powerpc
mechanisms of loading the keys/hashes from the firmware.
This patch moves the common code from load_uefi.c to keyring_handler.c
Signed-off-by: Nayna Jain <[email protected]>
Acked-by: Mimi Zohar <[email protected]>
---
security/integrity/Makefile | 3 +-
.../platform_certs/keyring_handler.c | 80 +++++++++++++++++++
.../platform_certs/keyring_handler.h | 32 ++++++++
security/integrity/platform_certs/load_uefi.c | 67 +---------------
4 files changed, 115 insertions(+), 67 deletions(-)
create mode 100644 security/integrity/platform_certs/keyring_handler.c
create mode 100644 security/integrity/platform_certs/keyring_handler.h
diff --git a/security/integrity/Makefile b/security/integrity/Makefile
index 35e6ca773734..351c9662994b 100644
--- a/security/integrity/Makefile
+++ b/security/integrity/Makefile
@@ -11,7 +11,8 @@ integrity-$(CONFIG_INTEGRITY_SIGNATURE) += digsig.o
integrity-$(CONFIG_INTEGRITY_ASYMMETRIC_KEYS) += digsig_asymmetric.o
integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o
integrity-$(CONFIG_LOAD_UEFI_KEYS) += platform_certs/efi_parser.o \
- platform_certs/load_uefi.o
+ platform_certs/load_uefi.o \
+ platform_certs/keyring_handler.o
integrity-$(CONFIG_LOAD_IPL_KEYS) += platform_certs/load_ipl_s390.o
obj-$(CONFIG_IMA) += ima/
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c
new file mode 100644
index 000000000000..c5ba695c10e3
--- /dev/null
+++ b/security/integrity/platform_certs/keyring_handler.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/efi.h>
+#include <linux/slab.h>
+#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
+#include "../integrity.h"
+
+static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID;
+static efi_guid_t efi_cert_x509_sha256_guid __initdata =
+ EFI_CERT_X509_SHA256_GUID;
+static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID;
+
+/*
+ * Blacklist a hash.
+ */
+static __init void uefi_blacklist_hash(const char *source, const void *data,
+ size_t len, const char *type,
+ size_t type_len)
+{
+ char *hash, *p;
+
+ hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL);
+ if (!hash)
+ return;
+ p = memcpy(hash, type, type_len);
+ p += type_len;
+ bin2hex(p, data, len);
+ p += len * 2;
+ *p = 0;
+
+ mark_hash_blacklisted(hash);
+ kfree(hash);
+}
+
+/*
+ * Blacklist an X509 TBS hash.
+ */
+static __init void uefi_blacklist_x509_tbs(const char *source,
+ const void *data, size_t len)
+{
+ uefi_blacklist_hash(source, data, len, "tbs:", 4);
+}
+
+/*
+ * Blacklist the hash of an executable.
+ */
+static __init void uefi_blacklist_binary(const char *source,
+ const void *data, size_t len)
+{
+ uefi_blacklist_hash(source, data, len, "bin:", 4);
+}
+
+/*
+ * Return the appropriate handler for particular signature list types found in
+ * the UEFI db and MokListRT tables.
+ */
+__init efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type)
+{
+ if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
+ return add_to_platform_keyring;
+ return 0;
+}
+
+/*
+ * Return the appropriate handler for particular signature list types found in
+ * the UEFI dbx and MokListXRT tables.
+ */
+__init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type)
+{
+ if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0)
+ return uefi_blacklist_x509_tbs;
+ if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
+ return uefi_blacklist_binary;
+ return 0;
+}
diff --git a/security/integrity/platform_certs/keyring_handler.h b/security/integrity/platform_certs/keyring_handler.h
new file mode 100644
index 000000000000..2462bfa08fe3
--- /dev/null
+++ b/security/integrity/platform_certs/keyring_handler.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef PLATFORM_CERTS_INTERNAL_H
+#define PLATFORM_CERTS_INTERNAL_H
+
+#include <linux/efi.h>
+
+void blacklist_hash(const char *source, const void *data,
+ size_t len, const char *type,
+ size_t type_len);
+
+/*
+ * Blacklist an X509 TBS hash.
+ */
+void blacklist_x509_tbs(const char *source, const void *data, size_t len);
+
+/*
+ * Blacklist the hash of an executable.
+ */
+void blacklist_binary(const char *source, const void *data, size_t len);
+
+/*
+ * Return the handler for particular signature list types found in the db.
+ */
+efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type);
+
+/*
+ * Return the handler for particular signature list types found in the dbx.
+ */
+efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type);
+
+#endif
diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
index 81b19c52832b..4369204a19cd 100644
--- a/security/integrity/platform_certs/load_uefi.c
+++ b/security/integrity/platform_certs/load_uefi.c
@@ -9,6 +9,7 @@
#include <keys/asymmetric-type.h>
#include <keys/system_keyring.h>
#include "../integrity.h"
+#include "keyring_handler.h"
static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID;
static efi_guid_t efi_cert_x509_sha256_guid __initdata =
@@ -67,72 +68,6 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
return db;
}
-/*
- * Blacklist a hash.
- */
-static __init void uefi_blacklist_hash(const char *source, const void *data,
- size_t len, const char *type,
- size_t type_len)
-{
- char *hash, *p;
-
- hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL);
- if (!hash)
- return;
- p = memcpy(hash, type, type_len);
- p += type_len;
- bin2hex(p, data, len);
- p += len * 2;
- *p = 0;
-
- mark_hash_blacklisted(hash);
- kfree(hash);
-}
-
-/*
- * Blacklist an X509 TBS hash.
- */
-static __init void uefi_blacklist_x509_tbs(const char *source,
- const void *data, size_t len)
-{
- uefi_blacklist_hash(source, data, len, "tbs:", 4);
-}
-
-/*
- * Blacklist the hash of an executable.
- */
-static __init void uefi_blacklist_binary(const char *source,
- const void *data, size_t len)
-{
- uefi_blacklist_hash(source, data, len, "bin:", 4);
-}
-
-/*
- * Return the appropriate handler for particular signature list types found in
- * the UEFI db and MokListRT tables.
- */
-static __init efi_element_handler_t get_handler_for_db(const efi_guid_t *
- sig_type)
-{
- if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
- return add_to_platform_keyring;
- return 0;
-}
-
-/*
- * Return the appropriate handler for particular signature list types found in
- * the UEFI dbx and MokListXRT tables.
- */
-static __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *
- sig_type)
-{
- if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0)
- return uefi_blacklist_x509_tbs;
- if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
- return uefi_blacklist_binary;
- return 0;
-}
-
/*
* Load the certs contained in the UEFI databases into the platform trusted
* keyring and the UEFI blacklisted X.509 cert SHA256 hashes into the blacklist
--
2.20.1
PowerNV secure variables, which store the keys used for OS kernel
verification, are managed by the firmware. These secure variables need to
be accessed by the userspace for addition/deletion of the certificates.
This patch adds the sysfs interface to expose secure variables for PowerNV
secureboot. The users shall use this interface for manipulating
the keys stored in the secure variables.
Signed-off-by: Nayna Jain <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
---
Documentation/ABI/testing/sysfs-secvar | 39 +++++
arch/powerpc/Kconfig | 11 ++
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/kernel/secvar-sysfs.c | 228 +++++++++++++++++++++++++
4 files changed, 279 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-secvar
create mode 100644 arch/powerpc/kernel/secvar-sysfs.c
diff --git a/Documentation/ABI/testing/sysfs-secvar b/Documentation/ABI/testing/sysfs-secvar
new file mode 100644
index 000000000000..bc0bedf2b662
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-secvar
@@ -0,0 +1,39 @@
+What: /sys/firmware/secvar
+Date: August 2019
+Contact: Nayna Jain <[email protected]>
+Description: This directory is created if the POWER firmware supports OS
+ secureboot, thereby secure variables. It exposes interface
+ for reading/writing the secure variables
+
+What: /sys/firmware/secvar/vars
+Date: August 2019
+Contact: Nayna Jain <[email protected]>
+Description: This directory lists all the secure variables that are supported
+ by the firmware.
+
+What: /sys/firmware/secvar/vars/<variable name>
+Date: August 2019
+Contact: Nayna Jain <[email protected]>
+Description: Each secure variable is represented as a directory named as
+ <variable_name>. The variable name is unique and is in ASCII
+ representation. The data and size can be determined by reading
+ their respective attribute files.
+
+What: /sys/firmware/secvar/vars/<variable_name>/size
+Date: August 2019
+Contact: Nayna Jain <[email protected]>
+Description: An integer representation of the size of the content of the
+ variable. In other words, it represents the size of the data.
+
+What: /sys/firmware/secvar/vars/<variable_name>/data
+Date: August 2019
+Contact: Nayna Jain h<[email protected]>
+Description: A read-only file containing the value of the variable. The size
+ of the file represents the maximum size of the variable data.
+
+What: /sys/firmware/secvar/vars/<variable_name>/update
+Date: August 2019
+Contact: Nayna Jain <[email protected]>
+Description: A write-only file that is used to submit the new value for the
+ variable. The size of the file represents the maximum size of
+ the variable data that can be written.
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c795039bdc73..949e747bc8c2 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -945,6 +945,17 @@ config PPC_SECURE_BOOT
to enable OS secure boot on systems that have firmware support for
it. If in doubt say N.
+config PPC_SECVAR_SYSFS
+ tristate "Enable sysfs interface for POWER secure variables"
+ default y
+ depends on PPC_SECURE_BOOT
+ depends on SYSFS
+ help
+ POWER secure variables are managed and controlled by firmware.
+ These variables are exposed to userspace via sysfs to enable
+ read/write operations on these variables. Say Y if you have
+ secure boot enabled and want to expose variables to userspace.
+
endmenu
config ISA_DMA_API
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 3cf26427334f..b216e9f316ee 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -162,6 +162,7 @@ obj-y += ucall.o
endif
obj-$(CONFIG_PPC_SECURE_BOOT) += secure_boot.o ima_arch.o secvar-ops.o
+obj-$(CONFIG_PPC_SECVAR_SYSFS) += secvar-sysfs.o
# Disable GCOV, KCOV & sanitizers in odd or sensitive code
GCOV_PROFILE_prom_init.o := n
diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c
new file mode 100644
index 000000000000..f0c4950649e0
--- /dev/null
+++ b/arch/powerpc/kernel/secvar-sysfs.c
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 IBM Corporation <[email protected]>
+ *
+ * This code exposes secure variables to user via sysfs
+ */
+
+#define pr_fmt(fmt) "secvar-sysfs: "fmt
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/string.h>
+#include <linux/of.h>
+#include <asm/secvar.h>
+
+#define NAME_MAX_SIZE 1024
+
+static struct kobject *secvar_kobj;
+static struct kset *secvar_kset;
+
+static ssize_t size_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ uint64_t dsize;
+ int rc;
+
+ rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, NULL, &dsize);
+ if (rc) {
+ pr_err("Error retrieving variable size %d\n", rc);
+ return rc;
+ }
+
+ rc = sprintf(buf, "%llu\n", dsize);
+
+ return rc;
+}
+
+static ssize_t data_read(struct file *filep, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf, loff_t off,
+ size_t count)
+{
+ uint64_t dsize;
+ char *data;
+ int rc;
+
+ rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, NULL, &dsize);
+ if (rc) {
+ pr_err("Error getting variable size %d\n", rc);
+ return rc;
+ }
+ pr_debug("dsize is %llu\n", dsize);
+
+ data = kzalloc(dsize, GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ rc = secvar_ops->get(kobj->name, strlen(kobj->name)+1, data, &dsize);
+ if (rc) {
+ pr_err("Error getting variable %d\n", rc);
+ goto data_fail;
+ }
+
+ rc = memory_read_from_buffer(buf, count, &off, data, dsize);
+
+data_fail:
+ kfree(data);
+ return rc;
+}
+
+static ssize_t update_write(struct file *filep, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf, loff_t off,
+ size_t count)
+{
+ int rc;
+
+ pr_debug("count is %ld\n", count);
+ rc = secvar_ops->set(kobj->name, strlen(kobj->name)+1, buf, count);
+ if (rc) {
+ pr_err("Error setting the variable %s\n", kobj->name);
+ return rc;
+ }
+
+ return count;
+}
+
+static struct kobj_attribute size_attr = __ATTR_RO(size);
+
+static struct bin_attribute data_attr = __BIN_ATTR_RO(data, 0);
+
+static struct bin_attribute update_attr = __BIN_ATTR_WO(update, 0);
+
+static struct bin_attribute *secvar_bin_attrs[] = {
+ &data_attr,
+ &update_attr,
+ NULL,
+};
+
+static struct attribute *secvar_attrs[] = {
+ &size_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group secvar_attr_group = {
+ .attrs = secvar_attrs,
+ .bin_attrs = secvar_bin_attrs,
+};
+__ATTRIBUTE_GROUPS(secvar_attr);
+
+static struct kobj_type secvar_ktype = {
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = secvar_attr_groups,
+};
+
+static int update_kobj_size(void)
+{
+
+ struct device_node *node;
+ u64 varsize;
+ int rc = 0;
+
+ node = of_find_compatible_node(NULL, NULL, "ibm,secboot-tpm-v1");
+ if (!of_device_is_available(node)) {
+ rc = -ENODEV;
+ goto out;
+ }
+
+ rc = of_property_read_u64(node, "max-var-size", &varsize);
+ if (rc)
+ goto out;
+
+ data_attr.size = varsize;
+ update_attr.size = varsize;
+
+out:
+ of_node_put(node);
+
+ return rc;
+}
+
+static int secvar_sysfs_load(void)
+{
+ char *name;
+ uint64_t namesize = 0;
+ struct kobject *kobj;
+ int rc;
+
+ name = kzalloc(NAME_MAX_SIZE, GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+
+ do {
+ rc = secvar_ops->get_next(name, &namesize, NAME_MAX_SIZE);
+ if (rc) {
+ if (rc != -ENOENT)
+ pr_err("error getting secvar from firmware %d\n",
+ rc);
+ break;
+ }
+
+ kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
+ if (!kobj)
+ return -ENOMEM;
+
+ kobject_init(kobj, &secvar_ktype);
+
+ rc = kobject_add(kobj, &secvar_kset->kobj, "%s", name);
+ if (rc) {
+ pr_warn("kobject_add error %d for attribute: %s\n", rc,
+ name);
+ kobject_put(kobj);
+ kobj = NULL;
+ }
+
+ if (kobj)
+ kobject_uevent(kobj, KOBJ_ADD);
+
+ } while (!rc);
+
+ kfree(name);
+ return rc;
+}
+
+static int secvar_sysfs_init(void)
+{
+ int rc;
+
+ if (!secvar_ops) {
+ pr_warn("secvar: failed to retrieve secvar operations.\n");
+ return -ENODEV;
+ }
+
+ secvar_kobj = kobject_create_and_add("secvar", firmware_kobj);
+ if (!secvar_kobj) {
+ pr_err("secvar: Failed to create firmware kobj\n");
+ return -ENOMEM;
+ }
+
+ secvar_kset = kset_create_and_add("vars", NULL, secvar_kobj);
+ if (!secvar_kset) {
+ pr_err("secvar: sysfs kobject registration failed.\n");
+ kobject_put(secvar_kobj);
+ return -ENOMEM;
+ }
+
+ rc = update_kobj_size();
+ if (rc) {
+ pr_err("Cannot read the size of the attribute\n");
+ return rc;
+ }
+
+ secvar_sysfs_load();
+
+ return 0;
+}
+
+static void secvar_sysfs_exit(void)
+{
+ kset_unregister(secvar_kset);
+ kobject_put(secvar_kobj);
+}
+
+late_initcall(secvar_sysfs_init);
+module_exit(secvar_sysfs_exit);
+
+MODULE_AUTHOR("Nayna Jain <[email protected]>");
+MODULE_DESCRIPTION("sysfs interface to POWER secure variables");
+MODULE_LICENSE("GPL");
--
2.20.1
On 10/24/19 5:47 PM, Nayna Jain wrote:
>
> diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
> index 378e3997845a..c1f25a760eb1 100644
> --- a/arch/powerpc/include/asm/opal-api.h
> +++ b/arch/powerpc/include/asm/opal-api.h
> @@ -211,7 +211,10 @@
> #define OPAL_MPIPL_UPDATE 173
> #define OPAL_MPIPL_REGISTER_TAG 174
> #define OPAL_MPIPL_QUERY_TAG 175
> -#define OPAL_LAST 175
> +#define OPAL_SECVAR_GET 176
> +#define OPAL_SECVAR_GET_NEXT 177
> +#define OPAL_SECVAR_ENQUEUE_UPDATE 178
> +#define OPAL_LAST 178
Adjust indentation in the above #defines.
> diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
> index a0cf8fba4d12..9986ac34b8e2 100644
> --- a/arch/powerpc/include/asm/opal.h
> +++ b/arch/powerpc/include/asm/opal.h
> @@ -298,6 +298,13 @@ int opal_sensor_group_clear(u32 group_hndl, int token);
> int opal_sensor_group_enable(u32 group_hndl, int token, bool enable);
> int opal_nx_coproc_init(uint32_t chip_id, uint32_t ct);
>
> +int opal_secvar_get(const char *key, uint64_t key_len, u8 *data,
> + uint64_t *data_size);
> +int opal_secvar_get_next(const char *key, uint64_t *key_len,
> + uint64_t key_buf_size);
> +int opal_secvar_enqueue_update(const char *key, uint64_t key_len, u8 *data,
> + uint64_t data_size);
> +
Fix alignment of the parameters in the 2nd line.
Same comment in a few other files in this change set.
> +
> +static int opal_get_variable(const char *key, uint64_t ksize,
> + u8 *data, uint64_t *dsize)
> +{
> + int rc;
> +
> + if (!key || !dsize)
> + return -EINVAL;
> +
> + *dsize = cpu_to_be64(*dsize);
> +
> + rc = opal_secvar_get(key, ksize, data, dsize);
> +
> + *dsize = be64_to_cpu(*dsize);
Is it ok to update dsize even if return code (rc) from opal_secvar_get
is an error? Just wanted to confirm.
> +
> + *keylen = cpu_to_be64(*keylen);
> +
> + rc = opal_secvar_get_next(key, keylen, keybufsize);
> +
> + *keylen = be64_to_cpu(*keylen);
Same comment as above.
> +
> + set_secvar_ops(&opal_secvar_ops);
Does this set function return status?
> +
> + return 0;
> +}
On 10/24/19 5:47 PM, Nayna Jain wrote:
> +static ssize_t size_show(struct kobject *kobj, struct kobj_attribute *attr,
> + char *buf)
> +{
> + uint64_t dsize;
> + int rc;
> +
> + rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, NULL, &dsize);
> + if (rc) {
> + pr_err("Error retrieving variable size %d\n", rc);
> + return rc;
> + }
> +
> + rc = sprintf(buf, "%llu\n", dsize);
> +
> + return rc;
> +}
nit: change it to "return sprintf(buf, "%llu\n", dsize);" instead.
> +
> +static ssize_t data_read(struct file *filep, struct kobject *kobj,
> + struct bin_attribute *attr, char *buf, loff_t off,
> + size_t count)
> +{
> + uint64_t dsize;
> + char *data;
> + int rc;
> +
> + rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, NULL, &dsize);
> + if (rc) {
> + pr_err("Error getting variable size %d\n", rc);
> + return rc;
> + }
> + pr_debug("dsize is %llu\n", dsize);
> +
> + data = kzalloc(dsize, GFP_KERNEL);
Is there any MAX\MIN limit on dsize that can be returned by secvar_ops?
Is it ok to not validate the dsize
> +
> +static ssize_t update_write(struct file *filep, struct kobject *kobj,
> + struct bin_attribute *attr, char *buf, loff_t off,
> + size_t count)
> +{
> + int rc;
> +
> + pr_debug("count is %ld\n", count);
> + rc = secvar_ops->set(kobj->name, strlen(kobj->name)+1, buf, count);
> + if (rc) {
> + pr_err("Error setting the variable %s\n", kobj->name);
> + return rc;
> + }
> +
> + return count;
> +}
Return value from this function can be a count (of bytes in buf?) or
error code. Could cause confusion.
> +
> +static int secvar_sysfs_load(void)
> +{
> + char *name;
> + uint64_t namesize = 0;
> + struct kobject *kobj;
> + int rc;
> +
> + name = kzalloc(NAME_MAX_SIZE, GFP_KERNEL);
> + if (!name)
> + return -ENOMEM;
> +
> + do {
> + rc = secvar_ops->get_next(name, &namesize, NAME_MAX_SIZE);
> + if (rc) {
> + if (rc != -ENOENT)
> + pr_err("error getting secvar from firmware %d\n",
> + rc);
> + break;
> + }
> +
> + kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
> + if (!kobj)
> + return -ENOMEM;
Memory allocated for "name" is leaked in this case.
> +
> + kobject_init(kobj, &secvar_ktype);
> +
> + rc = kobject_add(kobj, &secvar_kset->kobj, "%s", name);
> + if (rc) {
> + pr_warn("kobject_add error %d for attribute: %s\n", rc,
> + name);
> + kobject_put(kobj);
> + kobj = NULL;
> + }
> +
> + if (kobj)
> + kobject_uevent(kobj, KOBJ_ADD);
> +
> + } while (!rc);
> +
> + kfree(name);
> + return rc;
> +}