diff mbox series

[v6,3/3] integrity: support including firmware ".platform" keys at build time

Message ID 20211223013919.206273-4-nayna@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series integrity: support including firmware ".platform" keys at build time | expand

Commit Message

Nayna Jain Dec. 23, 2021, 1:39 a.m. UTC 
Allow firmware keys to be embedded in the Linux kernel and loaded onto
the ".platform" keyring on boot.

The firmware keys can be specified in a file as a list of PEM encoded
certificates using new config INTEGRITY_PLATFORM_KEYS. The certificates
are embedded in the image by converting the PEM-formatted certificates
into DER(binary) and generating
security/integrity/platform_certs/platform_certificate_list file at
build time. On boot, the embedded certs from the image are loaded onto
the ".platform" keyring.

Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
---
 security/integrity/Kconfig                    | 10 +++++++
 security/integrity/Makefile                   | 17 +++++++++++-
 .../integrity/platform_certs/platform_cert.S  | 23 ++++++++++++++++
 .../platform_certs/platform_keyring.c         | 26 +++++++++++++++++++
 4 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 security/integrity/platform_certs/platform_cert.S

Comments

Jarkko Sakkinen Dec. 29, 2021, 1:33 a.m. UTC | #1 
On Wed, Dec 22, 2021 at 08:39:19PM -0500, Nayna Jain wrote:
> Allow firmware keys to be embedded in the Linux kernel and loaded onto
> the ".platform" keyring on boot.
> 
> The firmware keys can be specified in a file as a list of PEM encoded
> certificates using new config INTEGRITY_PLATFORM_KEYS. The certificates
> are embedded in the image by converting the PEM-formatted certificates
> into DER(binary) and generating
> security/integrity/platform_certs/platform_certificate_list file at
> build time. On boot, the embedded certs from the image are loaded onto
> the ".platform" keyring.
> 
> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> ---
>  security/integrity/Kconfig                    | 10 +++++++
>  security/integrity/Makefile                   | 17 +++++++++++-
>  .../integrity/platform_certs/platform_cert.S  | 23 ++++++++++++++++
>  .../platform_certs/platform_keyring.c         | 26 +++++++++++++++++++
>  4 files changed, 75 insertions(+), 1 deletion(-)
>  create mode 100644 security/integrity/platform_certs/platform_cert.S
> 
> diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig
> index 71f0177e8716..9fccf1368b8a 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_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..46629f5ef4f6 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 $(call config_filename,INTEGRITY_PLATFORM_KEYS))
> +
>  obj-$(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_KEYS_FILENAME) FORCE
> +	$(call if_changed,extract_certs,$(CONFIG_INTEGRITY_PLATFORM_KEYS))
> +
> +clean-files := platform_certs/platform_certificate_list
> 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..b45de142c5f5 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_platform_certificate_list(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_platform_certificate_list);

Would not hurt to briefly explain the chosen initcall level in the commit
message.

> +
>  /*
>   * Create the trusted keyrings.
>   */
> -- 
> 2.27.0
> 

/Jarkko
diff mbox series

Patch

diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig
index 71f0177e8716..9fccf1368b8a 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_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..46629f5ef4f6 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 $(call config_filename,INTEGRITY_PLATFORM_KEYS))
+
 obj-$(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_KEYS_FILENAME) FORCE
+	$(call if_changed,extract_certs,$(CONFIG_INTEGRITY_PLATFORM_KEYS))
+
+clean-files := platform_certs/platform_certificate_list
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..b45de142c5f5 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_platform_certificate_list(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_platform_certificate_list);
+
 /*
  * Create the trusted keyrings.
  */