[PATCH v3] integrity: support including firmware ".platform" keys at build time
Nayna
nayna at linux.vnet.ibm.com
Tue Oct 19 18:25:07 UTC 2021
Gentle reminder for v3. Is this version good now for acceptance ?
Thanks & Regards,
- Nayna
On 10/4/21 10:52 AM, Nayna Jain wrote:
> Some firmware support secure boot by embedding static keys to verify the
> Linux kernel during boot. However, these firmware do not expose an
> interface for the kernel to load firmware keys onto ".platform" keyring.
> This would prevent kernel signature verification on kexec.
>
> For these environments, a new function load_builtin_platform_cert() is
> defined to load compiled in certificates onto the ".platform" keyring.
>
> load_certificate_list() is currently used for parsing compiled in
> certificates to be loaded onto the .builtin or .blacklist keyrings.
> Export load_certificate_list() allowing it to be used for parsing compiled
> in ".platform" keyring certificates as well.
>
> Reported-by: kernel test robot <lkp at intel.com>(auto build test ERROR)
> Signed-off-by: Nayna Jain <nayna at linux.ibm.com>
> ---
> NOTE: I am wondering if we should split this patch into two:
> (https://lore.kernel.org/linux-integrity/be4bd13d-659d-710d-08b9-1a34a65e5c5d@linux.vnet.ibm.com/).
> I can do so if you also prefer the same.
>
> v3:
> * Included Jarkko's feedback
> ** updated patch description to include approach.
> ** removed extern for function declaration in the .h file.
> * Included load_certificate_list() within #ifdef CONFIG_KEYS condition.
>
> v2:
> * Fixed the error reported by kernel test robot
> * Updated patch description based on Jarkko's feedback.
>
> 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 | 6 +++++
> 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, 91 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 279433783b10..64ee37f38b85 100644
> --- a/certs/Makefile
> +++ b/certs/Makefile
> @@ -3,7 +3,8 @@
> # Makefile for the linux kernel signature checking certificates.
> #
>
> -obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o common.o
> +obj-$(CONFIG_KEYS) += 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..d3f914d9a632 100644
> --- a/include/keys/system_keyring.h
> +++ b/include/keys/system_keyring.h
> @@ -10,6 +10,12 @@
>
> #include <linux/key.h>
>
> +#ifdef CONFIG_KEYS
> +int load_certificate_list(const u8 cert_list[],
> + const unsigned long list_size,
> + const struct key *keyring);
> +#endif
> +
> #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.
> */
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