[PATCH] integrity: support including firmware ".platform" keys at build time

From: Nayna Jain
Date: Fri Sep 10 2021 - 13:25:41 EST

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Firmware keys are loaded on boot onto the ".platform" keyring. In addition,
allow firmware keys to be compiled into the kernel and loaded onto the
".platform" keyring.

Signed-off-by: Nayna Jain <nayna@xxxxxxxxxxxxx>
---
certs/Makefile | 3 ++-
certs/blacklist.c | 1 -
certs/common.c | 2 +-
certs/common.h | 9 -------
certs/system_keyring.c | 1 -
include/keys/system_keyring.h | 3 +++
security/integrity/Kconfig | 10 +++++++
security/integrity/Makefile | 17 +++++++++++-
security/integrity/digsig.c | 2 +-
security/integrity/integrity.h | 6 +++++
.../integrity/platform_certs/platform_cert.S | 23 ++++++++++++++++
.../platform_certs/platform_keyring.c | 26 +++++++++++++++++++
12 files changed, 88 insertions(+), 15 deletions(-)
delete mode 100644 certs/common.h
create mode 100644 security/integrity/platform_certs/platform_cert.S

diff --git a/certs/Makefile b/certs/Makefile
index 359239a0ee9e..29765d0aefbb 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -3,7 +3,8 @@
# Makefile for the linux kernel signature checking certificates.
#

-obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o common.o
+obj-y += common.o
+obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o common.o
obj-$(CONFIG_SYSTEM_REVOCATION_LIST) += revocation_certificates.o
ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
diff --git a/certs/blacklist.c b/certs/blacklist.c
index c9a435b15af4..b95e9b19c42f 100644
--- a/certs/blacklist.c
+++ b/certs/blacklist.c
@@ -17,7 +17,6 @@
#include <linux/uidgid.h>
#include <keys/system_keyring.h>
#include "blacklist.h"
-#include "common.h"

static struct key *blacklist_keyring;

diff --git a/certs/common.c b/certs/common.c
index 16a220887a53..41f763415a00 100644
--- a/certs/common.c
+++ b/certs/common.c
@@ -2,7 +2,7 @@

#include <linux/kernel.h>
#include <linux/key.h>
-#include "common.h"
+#include <keys/system_keyring.h>

int load_certificate_list(const u8 cert_list[],
const unsigned long list_size,
diff --git a/certs/common.h b/certs/common.h
deleted file mode 100644
index abdb5795936b..000000000000
--- a/certs/common.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#ifndef _CERT_COMMON_H
-#define _CERT_COMMON_H
-
-int load_certificate_list(const u8 cert_list[], const unsigned long list_size,
- const struct key *keyring);
-
-#endif
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 692365dee2bd..d130d5a96e09 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -16,7 +16,6 @@
#include <keys/asymmetric-type.h>
#include <keys/system_keyring.h>
#include <crypto/pkcs7.h>
-#include "common.h"

static struct key *builtin_trusted_keys;
#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index 6acd3cf13a18..842d770b2a46 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -10,6 +10,9 @@

#include <linux/key.h>

+extern int load_certificate_list(const u8 cert_list[],
+ const unsigned long list_size,
+ const struct key *keyring);
#ifdef CONFIG_SYSTEM_TRUSTED_KEYRING

extern int restrict_link_by_builtin_trusted(struct key *keyring,
diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig
index 71f0177e8716..b2009b792882 100644
--- a/security/integrity/Kconfig
+++ b/security/integrity/Kconfig
@@ -62,6 +62,16 @@ config INTEGRITY_PLATFORM_KEYRING
provided by the platform for verifying the kexec'ed kerned image
and, possibly, the initramfs signature.

+config INTEGRITY_PLATFORM_BUILTIN_KEYS
+ string "Builtin X.509 keys for .platform keyring"
+ depends on KEYS
+ depends on ASYMMETRIC_KEY_TYPE
+ depends on INTEGRITY_PLATFORM_KEYRING
+ help
+ If set, this option should be the filename of a PEM-formatted file
+ containing X.509 certificates to be loaded onto the ".platform"
+ keyring.
+
config LOAD_UEFI_KEYS
depends on INTEGRITY_PLATFORM_KEYRING
depends on EFI
diff --git a/security/integrity/Makefile b/security/integrity/Makefile
index 7ee39d66cf16..a45f083589b8 100644
--- a/security/integrity/Makefile
+++ b/security/integrity/Makefile
@@ -3,13 +3,18 @@
# Makefile for caching inode integrity data (iint)
#

+quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2))
+ cmd_extract_certs = scripts/extract-cert $(2) $@
+$(eval $(call config_filename,INTEGRITY_PLATFORM_BUILTIN_KEYS))
+
obj-$(CONFIG_INTEGRITY) += integrity.o

integrity-y := iint.o
integrity-$(CONFIG_INTEGRITY_AUDIT) += integrity_audit.o
integrity-$(CONFIG_INTEGRITY_SIGNATURE) += digsig.o
integrity-$(CONFIG_INTEGRITY_ASYMMETRIC_KEYS) += digsig_asymmetric.o
-integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o
+integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o \
+ platform_certs/platform_cert.o
integrity-$(CONFIG_LOAD_UEFI_KEYS) += platform_certs/efi_parser.o \
platform_certs/load_uefi.o \
platform_certs/keyring_handler.o
@@ -19,3 +24,13 @@ integrity-$(CONFIG_LOAD_PPC_KEYS) += platform_certs/efi_parser.o \
platform_certs/keyring_handler.o
obj-$(CONFIG_IMA) += ima/
obj-$(CONFIG_EVM) += evm/
+
+
+$(obj)/platform_certs/platform_cert.o: $(obj)/platform_certs/platform_certificate_list
+
+targets += platform_certificate_list
+
+$(obj)/platform_certs/platform_certificate_list: scripts/extract-cert $(INTEGRITY_PLATFORM_BUILTIN_KEYS_FILENAME) FORCE
+ $(call if_changed,extract_certs,$(CONFIG_INTEGRITY_PLATFORM_BUILTIN_KEYS))
+
+clean-files := platform_certs/platform_certificate_list
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 3b06a01bd0fd..0ea40ed8dfcb 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -38,7 +38,7 @@ static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
#define restrict_link_to_ima restrict_link_by_builtin_trusted
#endif

-static struct key *integrity_keyring_from_id(const unsigned int id)
+struct key *integrity_keyring_from_id(const unsigned int id)
{
if (id >= INTEGRITY_KEYRING_MAX)
return ERR_PTR(-EINVAL);
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 547425c20e11..feb84e1b1105 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -167,6 +167,7 @@ int __init integrity_init_keyring(const unsigned int id);
int __init integrity_load_x509(const unsigned int id, const char *path);
int __init integrity_load_cert(const unsigned int id, const char *source,
const void *data, size_t len, key_perm_t perm);
+struct key *integrity_keyring_from_id(const unsigned int id);
#else

static inline int integrity_digsig_verify(const unsigned int id,
@@ -194,6 +195,11 @@ static inline int __init integrity_load_cert(const unsigned int id,
{
return 0;
}
+
+static inline struct key *integrity_keyring_from_id(const unsigned int id)
+{
+ return ERR_PTR(-EOPNOTSUPP);
+}
#endif /* CONFIG_INTEGRITY_SIGNATURE */

#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
diff --git a/security/integrity/platform_certs/platform_cert.S b/security/integrity/platform_certs/platform_cert.S
new file mode 100644
index 000000000000..20bccce5dc5a
--- /dev/null
+++ b/security/integrity/platform_certs/platform_cert.S
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/export.h>
+#include <linux/init.h>
+
+ __INITRODATA
+
+ .align 8
+#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
+ .globl platform_certificate_list
+platform_certificate_list:
+__cert_list_start:
+ .incbin "security/integrity/platform_certs/platform_certificate_list"
+__cert_list_end:
+#endif
+
+ .align 8
+ .globl platform_certificate_list_size
+platform_certificate_list_size:
+#ifdef CONFIG_64BIT
+ .quad __cert_list_end - __cert_list_start
+#else
+ .long __cert_list_end - __cert_list_start
+#endif
diff --git a/security/integrity/platform_certs/platform_keyring.c b/security/integrity/platform_certs/platform_keyring.c
index bcafd7387729..17535050d08d 100644
--- a/security/integrity/platform_certs/platform_keyring.c
+++ b/security/integrity/platform_certs/platform_keyring.c
@@ -12,8 +12,12 @@
#include <linux/cred.h>
#include <linux/err.h>
#include <linux/slab.h>
+#include <keys/system_keyring.h>
#include "../integrity.h"

+extern __initconst const u8 platform_certificate_list[];
+extern __initconst const unsigned long platform_certificate_list_size;
+
/**
* add_to_platform_keyring - Add to platform keyring without validation.
* @source: Source of key
@@ -37,6 +41,28 @@ void __init add_to_platform_keyring(const char *source, const void *data,
pr_info("Error adding keys to platform keyring %s\n", source);
}

+static __init int load_builtin_platform_cert(void)
+{
+ const u8 *p;
+ unsigned long size;
+ int rc;
+ struct key *keyring;
+
+ p = platform_certificate_list;
+ size = platform_certificate_list_size;
+
+ keyring = integrity_keyring_from_id(INTEGRITY_KEYRING_PLATFORM);
+ if (IS_ERR(keyring))
+ return PTR_ERR(keyring);
+
+ rc = load_certificate_list(p, size, keyring);
+ if (rc)
+ pr_info("Error adding keys to platform keyring %d\n", rc);
+
+ return rc;
+}
+late_initcall(load_builtin_platform_cert);
+
/*
* Create the trusted keyrings.
*/
--
2.27.0

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Next in thread: kernel test robot: "Re: [PATCH] integrity: support including firmware ".platform" keys at build time"
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