Here's my take on v5 of Eric Snowberg's patches[1]:
This series of patches adds support for EFI_CERT_X509_GUID entries [2]. It has
been expanded to not only include dbx entries but also entries in the mokx.
Additionally Eric included his patches to preload these certificate [3].
The patches can be found on the following branch:
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=keys-cve-2020-26541-branch
Changes:
ver #3:
- Rolled in changes from Eric to fix conditional building issues[7].
ver #2:
- Rolled in a fix to the second patch to include certs/common.h in
certs/common.c[6].
ver #1:
- I've modified the first patch in the series to fix a configuration
problem[4][5], to move the added functions to a more logical place
within thefile and to add kerneldoc comments.
Link: https://lore.kernel.org/r/[email protected] [1]
Link: https://patchwork.kernel.org/project/linux-security-module/patch/[email protected]/ [2]
Link: https://lore.kernel.org/patchwork/cover/1315485/ [3]
Link: https://lore.kernel.org/r/[email protected]/ [4]
Link: https://lore.kernel.org/r/[email protected]/ [5]
Link: https://lore.kernel.org/r/[email protected]/ [6]
Link: https://lore.kernel.org/r/161428671215.677100.6372209948022011988.stgit@warthog.procyon.org.uk/ # v1 posting
Link: https://lore.kernel.org/r/161433310139.902181.11787442834918634133.stgit@warthog.procyon.org.uk/ # v2 posting
Link: https://lore.kernel.org/r/[email protected]/ [7]
David
---
Eric Snowberg (4):
certs: Add EFI_CERT_X509_GUID support for dbx entries
certs: Move load_system_certificate_list to a common function
certs: Add ability to preload revocation certs
integrity: Load mokx variables into the blacklist keyring
certs/Kconfig | 8 +++
certs/Makefile | 21 ++++++-
certs/blacklist.c | 21 +++++++
certs/common.c | 57 +++++++++++++++++++
certs/common.h | 9 +++
certs/revocation_certificates.S | 21 +++++++
certs/system_keyring.c | 49 +---------------
scripts/Makefile | 1 +
security/integrity/platform_certs/load_uefi.c | 20 ++++++-
9 files changed, 156 insertions(+), 51 deletions(-)
create mode 100644 certs/common.c
create mode 100644 certs/common.h
create mode 100644 certs/revocation_certificates.S
From: Eric Snowberg <[email protected]>
This fixes CVE-2020-26541.
The Secure Boot Forbidden Signature Database, dbx, contains a list of now
revoked signatures and keys previously approved to boot with UEFI Secure
Boot enabled. The dbx is capable of containing any number of
EFI_CERT_X509_SHA256_GUID, EFI_CERT_SHA256_GUID, and EFI_CERT_X509_GUID
entries.
Currently when EFI_CERT_X509_GUID are contained in the dbx, the entries are
skipped.
Add support for EFI_CERT_X509_GUID dbx entries. When a EFI_CERT_X509_GUID
is found, it is added as an asymmetrical key to the .blacklist keyring.
Anytime the .platform keyring is used, the keys in the .blacklist keyring
are referenced, if a matching key is found, the key will be rejected.
[DH: Made the following changes:
- Added to have a config option to enable the facility. This allows a
Kconfig solution to make sure that pkcs7_validate_trust() is enabled.
- Moved the functions out from the middle of the blacklist functions.
- Added kerneldoc comments.]
Signed-off-by: Eric Snowberg <[email protected]>
Signed-off-by: David Howells <[email protected]>
Reviewed-by: Jarkko Sakkinen <[email protected]>
cc: Randy Dunlap <[email protected]>
cc: Mickaël Salaün <[email protected]>
cc: Arnd Bergmann <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/ # v2
Link: https://lore.kernel.org/r/[email protected]/ # v3
Link: https://lore.kernel.org/r/[email protected]/ # v4
Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/ # v5
Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/161428672051.677100.11064981943343605138.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/161433310942.902181.4901864302675874242.stgit@warthog.procyon.org.uk/ # v2
---
certs/Kconfig | 9 ++++
certs/blacklist.c | 43 ++++++++++++++++++++
certs/blacklist.h | 2 +
certs/system_keyring.c | 6 +++
include/keys/system_keyring.h | 15 +++++++
.../integrity/platform_certs/keyring_handler.c | 11 +++++
6 files changed, 86 insertions(+)
diff --git a/certs/Kconfig b/certs/Kconfig
index c94e93d8bccf..76e469b56a77 100644
--- a/certs/Kconfig
+++ b/certs/Kconfig
@@ -83,4 +83,13 @@ config SYSTEM_BLACKLIST_HASH_LIST
wrapper to incorporate the list into the kernel. Each <hash> should
be a string of hex digits.
+config SYSTEM_REVOCATION_LIST
+ bool "Provide system-wide ring of revocation certificates"
+ depends on SYSTEM_BLACKLIST_KEYRING
+ depends on PKCS7_MESSAGE_PARSER=y
+ help
+ If set, this allows revocation certificates to be stored in the
+ blacklist keyring and implements a hook whereby a PKCS#7 message can
+ be checked to see if it matches such a certificate.
+
endmenu
diff --git a/certs/blacklist.c b/certs/blacklist.c
index bffe4c6f4a9e..2b8644123d5f 100644
--- a/certs/blacklist.c
+++ b/certs/blacklist.c
@@ -145,6 +145,49 @@ int is_binary_blacklisted(const u8 *hash, size_t hash_len)
}
EXPORT_SYMBOL_GPL(is_binary_blacklisted);
+#ifdef CONFIG_SYSTEM_REVOCATION_LIST
+/**
+ * add_key_to_revocation_list - Add a revocation certificate to the blacklist
+ * @data: The data blob containing the certificate
+ * @size: The size of data blob
+ */
+int add_key_to_revocation_list(const char *data, size_t size)
+{
+ key_ref_t key;
+
+ key = key_create_or_update(make_key_ref(blacklist_keyring, true),
+ "asymmetric",
+ NULL,
+ data,
+ size,
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW),
+ KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN);
+
+ if (IS_ERR(key)) {
+ pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key));
+ return PTR_ERR(key);
+ }
+
+ return 0;
+}
+
+/**
+ * is_key_on_revocation_list - Determine if the key for a PKCS#7 message is revoked
+ * @pkcs7: The PKCS#7 message to check
+ */
+int is_key_on_revocation_list(struct pkcs7_message *pkcs7)
+{
+ int ret;
+
+ ret = pkcs7_validate_trust(pkcs7, blacklist_keyring);
+
+ if (ret == 0)
+ return -EKEYREJECTED;
+
+ return -ENOKEY;
+}
+#endif
+
/*
* Initialise the blacklist
*/
diff --git a/certs/blacklist.h b/certs/blacklist.h
index 1efd6fa0dc60..51b320cf8574 100644
--- a/certs/blacklist.h
+++ b/certs/blacklist.h
@@ -1,3 +1,5 @@
#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <crypto/pkcs7.h>
extern const char __initconst *const blacklist_hashes[];
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 4b693da488f1..ed98754d5795 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -242,6 +242,12 @@ int verify_pkcs7_message_sig(const void *data, size_t len,
pr_devel("PKCS#7 platform keyring is not available\n");
goto error;
}
+
+ ret = is_key_on_revocation_list(pkcs7);
+ if (ret != -ENOKEY) {
+ pr_devel("PKCS#7 platform key is on revocation list\n");
+ goto error;
+ }
}
ret = pkcs7_validate_trust(pkcs7, trusted_keys);
if (ret < 0) {
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index fb8b07daa9d1..875e002a4180 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -31,6 +31,7 @@ extern int restrict_link_by_builtin_and_secondary_trusted(
#define restrict_link_by_builtin_and_secondary_trusted restrict_link_by_builtin_trusted
#endif
+extern struct pkcs7_message *pkcs7;
#ifdef CONFIG_SYSTEM_BLACKLIST_KEYRING
extern int mark_hash_blacklisted(const char *hash);
extern int is_hash_blacklisted(const u8 *hash, size_t hash_len,
@@ -49,6 +50,20 @@ static inline int is_binary_blacklisted(const u8 *hash, size_t hash_len)
}
#endif
+#ifdef CONFIG_SYSTEM_REVOCATION_LIST
+extern int add_key_to_revocation_list(const char *data, size_t size);
+extern int is_key_on_revocation_list(struct pkcs7_message *pkcs7);
+#else
+static inline int add_key_to_revocation_list(const char *data, size_t size)
+{
+ return 0;
+}
+static inline int is_key_on_revocation_list(struct pkcs7_message *pkcs7)
+{
+ return -ENOKEY;
+}
+#endif
+
#ifdef CONFIG_IMA_BLACKLIST_KEYRING
extern struct key *ima_blacklist_keyring;
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c
index c5ba695c10e3..5604bd57c990 100644
--- a/security/integrity/platform_certs/keyring_handler.c
+++ b/security/integrity/platform_certs/keyring_handler.c
@@ -55,6 +55,15 @@ static __init void uefi_blacklist_binary(const char *source,
uefi_blacklist_hash(source, data, len, "bin:", 4);
}
+/*
+ * Add an X509 cert to the revocation list.
+ */
+static __init void uefi_revocation_list_x509(const char *source,
+ const void *data, size_t len)
+{
+ add_key_to_revocation_list(data, len);
+}
+
/*
* Return the appropriate handler for particular signature list types found in
* the UEFI db and MokListRT tables.
@@ -76,5 +85,7 @@ __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type)
return uefi_blacklist_x509_tbs;
if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
return uefi_blacklist_binary;
+ if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
+ return uefi_revocation_list_x509;
return 0;
}
From: Eric Snowberg <[email protected]>
Move functionality within load_system_certificate_list to a common
function, so it can be reused in the future.
DH Changes:
- Added inclusion of common.h to common.c (Eric [1]).
Signed-off-by: Eric Snowberg <[email protected]>
Acked-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: David Howells <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/ # v5
Link: https://lore.kernel.org/r/[email protected]/ [1]
Link: https://lore.kernel.org/r/161428672825.677100.7545516389752262918.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/161433311696.902181.3599366124784670368.stgit@warthog.procyon.org.uk/ # v2
---
certs/Makefile | 2 +-
certs/common.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++
certs/common.h | 9 ++++++++
certs/system_keyring.c | 49 +++--------------------------------------
4 files changed, 70 insertions(+), 47 deletions(-)
create mode 100644 certs/common.c
create mode 100644 certs/common.h
diff --git a/certs/Makefile b/certs/Makefile
index f4c25b67aad9..f4b90bad8690 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -3,7 +3,7 @@
# Makefile for the linux kernel signature checking certificates.
#
-obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
+obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o common.o
obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o
ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
diff --git a/certs/common.c b/certs/common.c
new file mode 100644
index 000000000000..16a220887a53
--- /dev/null
+++ b/certs/common.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/kernel.h>
+#include <linux/key.h>
+#include "common.h"
+
+int load_certificate_list(const u8 cert_list[],
+ const unsigned long list_size,
+ const struct key *keyring)
+{
+ key_ref_t key;
+ const u8 *p, *end;
+ size_t plen;
+
+ p = cert_list;
+ end = p + list_size;
+ while (p < end) {
+ /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
+ * than 256 bytes in size.
+ */
+ if (end - p < 4)
+ goto dodgy_cert;
+ if (p[0] != 0x30 &&
+ p[1] != 0x82)
+ goto dodgy_cert;
+ plen = (p[2] << 8) | p[3];
+ plen += 4;
+ if (plen > end - p)
+ goto dodgy_cert;
+
+ key = key_create_or_update(make_key_ref(keyring, 1),
+ "asymmetric",
+ NULL,
+ p,
+ plen,
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ),
+ KEY_ALLOC_NOT_IN_QUOTA |
+ KEY_ALLOC_BUILT_IN |
+ KEY_ALLOC_BYPASS_RESTRICTION);
+ if (IS_ERR(key)) {
+ pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
+ PTR_ERR(key));
+ } else {
+ pr_notice("Loaded X.509 cert '%s'\n",
+ key_ref_to_ptr(key)->description);
+ key_ref_put(key);
+ }
+ p += plen;
+ }
+
+ return 0;
+
+dodgy_cert:
+ pr_err("Problem parsing in-kernel X.509 certificate list\n");
+ return 0;
+}
diff --git a/certs/common.h b/certs/common.h
new file mode 100644
index 000000000000..abdb5795936b
--- /dev/null
+++ b/certs/common.h
@@ -0,0 +1,9 @@
+/* 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 ed98754d5795..0c9a4795e847 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -16,6 +16,7 @@
#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
@@ -137,54 +138,10 @@ device_initcall(system_trusted_keyring_init);
*/
static __init int load_system_certificate_list(void)
{
- key_ref_t key;
- const u8 *p, *end;
- size_t plen;
-
pr_notice("Loading compiled-in X.509 certificates\n");
- p = system_certificate_list;
- end = p + system_certificate_list_size;
- while (p < end) {
- /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
- * than 256 bytes in size.
- */
- if (end - p < 4)
- goto dodgy_cert;
- if (p[0] != 0x30 &&
- p[1] != 0x82)
- goto dodgy_cert;
- plen = (p[2] << 8) | p[3];
- plen += 4;
- if (plen > end - p)
- goto dodgy_cert;
-
- key = key_create_or_update(make_key_ref(builtin_trusted_keys, 1),
- "asymmetric",
- NULL,
- p,
- plen,
- ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
- KEY_USR_VIEW | KEY_USR_READ),
- KEY_ALLOC_NOT_IN_QUOTA |
- KEY_ALLOC_BUILT_IN |
- KEY_ALLOC_BYPASS_RESTRICTION);
- if (IS_ERR(key)) {
- pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
- PTR_ERR(key));
- } else {
- pr_notice("Loaded X.509 cert '%s'\n",
- key_ref_to_ptr(key)->description);
- key_ref_put(key);
- }
- p += plen;
- }
-
- return 0;
-
-dodgy_cert:
- pr_err("Problem parsing in-kernel X.509 certificate list\n");
- return 0;
+ return load_certificate_list(system_certificate_list, system_certificate_list_size,
+ builtin_trusted_keys);
}
late_initcall(load_system_certificate_list);
From: Eric Snowberg <[email protected]>
During boot the Secure Boot Forbidden Signature Database, dbx,
is loaded into the blacklist keyring. Systems booted with shim
have an equivalent Forbidden Signature Database called mokx.
Currently mokx is only used by shim and grub, the contents are
ignored by the kernel.
Add the ability to load mokx into the blacklist keyring during boot.
Signed-off-by: Eric Snowberg <[email protected]>
Suggested-by: James Bottomley <[email protected]>
Signed-off-by: David Howells <[email protected]>
Reviewed-by: Jarkko Sakkinen <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/ # v5
Link: https://lore.kernel.org/r/c33c8e3839a41e9654f41cc92c7231104931b1d7.camel@HansenPartnership.com/
Link: https://lore.kernel.org/r/161428674320.677100.12637282414018170743.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/161433313205.902181.2502803393898221637.stgit@warthog.procyon.org.uk/ # v2
---
security/integrity/platform_certs/load_uefi.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
index ee4b4c666854..f290f78c3f30 100644
--- a/security/integrity/platform_certs/load_uefi.c
+++ b/security/integrity/platform_certs/load_uefi.c
@@ -132,8 +132,9 @@ static int __init load_moklist_certs(void)
static int __init load_uefi_certs(void)
{
efi_guid_t secure_var = EFI_IMAGE_SECURITY_DATABASE_GUID;
- void *db = NULL, *dbx = NULL;
- unsigned long dbsize = 0, dbxsize = 0;
+ efi_guid_t mok_var = EFI_SHIM_LOCK_GUID;
+ void *db = NULL, *dbx = NULL, *mokx = NULL;
+ unsigned long dbsize = 0, dbxsize = 0, mokxsize = 0;
efi_status_t status;
int rc = 0;
@@ -175,6 +176,21 @@ static int __init load_uefi_certs(void)
kfree(dbx);
}
+ mokx = get_cert_list(L"MokListXRT", &mok_var, &mokxsize, &status);
+ if (!mokx) {
+ if (status == EFI_NOT_FOUND)
+ pr_debug("mokx variable wasn't found\n");
+ else
+ pr_info("Couldn't get mokx list\n");
+ } else {
+ rc = parse_efi_signature_list("UEFI:MokListXRT",
+ mokx, mokxsize,
+ get_handler_for_dbx);
+ if (rc)
+ pr_err("Couldn't parse mokx signatures %d\n", rc);
+ kfree(mokx);
+ }
+
/* Load the MokListRT certs */
rc = load_moklist_certs();
From: Eric Snowberg <[email protected]>
Add a new Kconfig option called SYSTEM_REVOCATION_KEYS. If set,
this option should be the filename of a PEM-formated file containing
X.509 certificates to be included in the default blacklist keyring.
DH Changes:
- Make the new Kconfig option depend on SYSTEM_REVOCATION_LIST.
- Fix SYSTEM_REVOCATION_KEYS=n, but CONFIG_SYSTEM_REVOCATION_LIST=y[1][2].
- Use CONFIG_SYSTEM_REVOCATION_LIST for extract-cert[3].
- Use CONFIG_SYSTEM_REVOCATION_LIST for revocation_certificates.o[3].
Signed-off-by: Eric Snowberg <[email protected]>
Acked-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: David Howells <[email protected]>
cc: Randy Dunlap <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/ # v5
Link: https://lore.kernel.org/r/161428673564.677100.4112098280028451629.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/161433312452.902181.4146169951896577982.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/[email protected]/ [1]
Link: https://lore.kernel.org/r/[email protected]/ [2]
Link: https://lore.kernel.org/keyrings/[email protected]/ [3]
---
certs/Kconfig | 8 ++++++++
certs/Makefile | 19 +++++++++++++++++--
certs/blacklist.c | 21 +++++++++++++++++++++
certs/revocation_certificates.S | 21 +++++++++++++++++++++
scripts/Makefile | 1 +
5 files changed, 68 insertions(+), 2 deletions(-)
create mode 100644 certs/revocation_certificates.S
diff --git a/certs/Kconfig b/certs/Kconfig
index 76e469b56a77..ab88d2a7f3c7 100644
--- a/certs/Kconfig
+++ b/certs/Kconfig
@@ -92,4 +92,12 @@ config SYSTEM_REVOCATION_LIST
blacklist keyring and implements a hook whereby a PKCS#7 message can
be checked to see if it matches such a certificate.
+config SYSTEM_REVOCATION_KEYS
+ string "X.509 certificates to be preloaded into the system blacklist keyring"
+ depends on SYSTEM_REVOCATION_LIST
+ help
+ If set, this option should be the filename of a PEM-formatted file
+ containing X.509 certificates to be included in the default blacklist
+ keyring.
+
endmenu
diff --git a/certs/Makefile b/certs/Makefile
index f4b90bad8690..b6db52ebf0be 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -4,7 +4,8 @@
#
obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o common.o
-obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o
+obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o common.o
+obj-$(CONFIG_SYSTEM_REVOCATION_LIST) += revocation_certificates.o
ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
else
@@ -29,7 +30,7 @@ $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREF
$(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS))
endif # CONFIG_SYSTEM_TRUSTED_KEYRING
-clean-files := x509_certificate_list .x509.list
+clean-files := x509_certificate_list .x509.list x509_revocation_list
ifeq ($(CONFIG_MODULE_SIG),y)
###############################################################################
@@ -104,3 +105,17 @@ targets += signing_key.x509
$(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE
$(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
endif # CONFIG_MODULE_SIG
+
+ifeq ($(CONFIG_SYSTEM_REVOCATION_LIST),y)
+
+$(eval $(call config_filename,SYSTEM_REVOCATION_KEYS))
+
+$(obj)/revocation_certificates.o: $(obj)/x509_revocation_list
+
+quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2))
+ cmd_extract_certs = scripts/extract-cert $(2) $@
+
+targets += x509_revocation_list
+$(obj)/x509_revocation_list: scripts/extract-cert $(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(SYSTEM_REVOCATION_KEYS_FILENAME) FORCE
+ $(call if_changed,extract_certs,$(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_REVOCATION_KEYS))
+endif
diff --git a/certs/blacklist.c b/certs/blacklist.c
index 2b8644123d5f..c9a435b15af4 100644
--- a/certs/blacklist.c
+++ b/certs/blacklist.c
@@ -17,9 +17,15 @@
#include <linux/uidgid.h>
#include <keys/system_keyring.h>
#include "blacklist.h"
+#include "common.h"
static struct key *blacklist_keyring;
+#ifdef CONFIG_SYSTEM_REVOCATION_LIST
+extern __initconst const u8 revocation_certificate_list[];
+extern __initconst const unsigned long revocation_certificate_list_size;
+#endif
+
/*
* The description must be a type prefix, a colon and then an even number of
* hex digits. The hash is kept in the description.
@@ -220,3 +226,18 @@ static int __init blacklist_init(void)
* Must be initialised before we try and load the keys into the keyring.
*/
device_initcall(blacklist_init);
+
+#ifdef CONFIG_SYSTEM_REVOCATION_LIST
+/*
+ * Load the compiled-in list of revocation X.509 certificates.
+ */
+static __init int load_revocation_certificate_list(void)
+{
+ if (revocation_certificate_list_size)
+ pr_notice("Loading compiled-in revocation X.509 certificates\n");
+
+ return load_certificate_list(revocation_certificate_list, revocation_certificate_list_size,
+ blacklist_keyring);
+}
+late_initcall(load_revocation_certificate_list);
+#endif
diff --git a/certs/revocation_certificates.S b/certs/revocation_certificates.S
new file mode 100644
index 000000000000..f21aae8a8f0e
--- /dev/null
+++ b/certs/revocation_certificates.S
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/export.h>
+#include <linux/init.h>
+
+ __INITRODATA
+
+ .align 8
+ .globl revocation_certificate_list
+revocation_certificate_list:
+__revocation_list_start:
+ .incbin "certs/x509_revocation_list"
+__revocation_list_end:
+
+ .align 8
+ .globl revocation_certificate_list_size
+revocation_certificate_list_size:
+#ifdef CONFIG_64BIT
+ .quad __revocation_list_end - __revocation_list_start
+#else
+ .long __revocation_list_end - __revocation_list_start
+#endif
diff --git a/scripts/Makefile b/scripts/Makefile
index b5418ec587fb..bd0718f7c493 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -11,6 +11,7 @@ hostprogs-always-$(CONFIG_ASN1) += asn1_compiler
hostprogs-always-$(CONFIG_MODULE_SIG_FORMAT) += sign-file
hostprogs-always-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += extract-cert
hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert
+hostprogs-always-$(CONFIG_SYSTEM_REVOCATION_LIST) += extract-cert
HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include
HOSTCFLAGS_asn1_compiler.o = -I$(srctree)/include
On Tue, Mar 09, 2021 at 01:20:42PM +0000, David Howells wrote:
>
> Here's my take on v5 of Eric Snowberg's patches[1]:
>
> This series of patches adds support for EFI_CERT_X509_GUID entries [2]. It has
> been expanded to not only include dbx entries but also entries in the mokx.
> Additionally Eric included his patches to preload these certificate [3].
>
> The patches can be found on the following branch:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=keys-cve-2020-26541-branch
>
> Changes:
>
> ver #3:
> - Rolled in changes from Eric to fix conditional building issues[7].
>
> ver #2:
> - Rolled in a fix to the second patch to include certs/common.h in
> certs/common.c[6].
>
> ver #1:
> - I've modified the first patch in the series to fix a configuration
> problem[4][5], to move the added functions to a more logical place
> within thefile and to add kerneldoc comments.
>
> Link: https://lore.kernel.org/r/[email protected] [1]
> Link: https://patchwork.kernel.org/project/linux-security-module/patch/[email protected]/ [2]
> Link: https://lore.kernel.org/patchwork/cover/1315485/ [3]
> Link: https://lore.kernel.org/r/[email protected]/ [4]
> Link: https://lore.kernel.org/r/[email protected]/ [5]
> Link: https://lore.kernel.org/r/[email protected]/ [6]
> Link: https://lore.kernel.org/r/161428671215.677100.6372209948022011988.stgit@warthog.procyon.org.uk/ # v1 posting
> Link: https://lore.kernel.org/r/161433310139.902181.11787442834918634133.stgit@warthog.procyon.org.uk/ # v2 posting
> Link: https://lore.kernel.org/r/[email protected]/ [7]
>
> David
> ---
> Eric Snowberg (4):
> certs: Add EFI_CERT_X509_GUID support for dbx entries
> certs: Move load_system_certificate_list to a common function
> certs: Add ability to preload revocation certs
> integrity: Load mokx variables into the blacklist keyring
>
>
> certs/Kconfig | 8 +++
> certs/Makefile | 21 ++++++-
> certs/blacklist.c | 21 +++++++
> certs/common.c | 57 +++++++++++++++++++
> certs/common.h | 9 +++
> certs/revocation_certificates.S | 21 +++++++
> certs/system_keyring.c | 49 +---------------
> scripts/Makefile | 1 +
> security/integrity/platform_certs/load_uefi.c | 20 ++++++-
> 9 files changed, 156 insertions(+), 51 deletions(-)
> create mode 100644 certs/common.c
> create mode 100644 certs/common.h
> create mode 100644 certs/revocation_certificates.S
>
>
>
Looks good to me.
/Jarkko
Hi Eric,
Can you check this patch? I rolled your changes into it.
David
> On Mar 10, 2021, at 2:08 PM, David Howells <[email protected]> wrote:
>
> Can you check this patch? I rolled your changes into it.
Looks good to me, thanks.