diff options
| author | Eric Snowberg <[email protected]> | 2021-01-22 13:10:51 -0500 |
|---|---|---|
| committer | David Howells <[email protected]> | 2021-03-11 16:31:28 +0000 |
| commit | 56c5812623f95313f6a46fbf0beee7fa17c68bbf (patch) | |
| tree | 563b2242fb6013a9a277102e9874354de0c27cb4 /security | |
| parent | 8f0bfc25c907f38e7f9dc498e8f43000d77327ef (diff) | |
certs: Add EFI_CERT_X509_GUID support for dbx entries
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.[1][2]
- 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]/ # rfc
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]/ # v5
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
Link: https://lore.kernel.org/r/161529605075.163428.14625520893961300757.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/[email protected]/ [1]
Link: https://lore.kernel.org/r/[email protected]/ [2]
Diffstat (limited to 'security')
| -rw-r--r-- | security/integrity/platform_certs/keyring_handler.c | 11 |
1 files changed, 11 insertions, 0 deletions
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 @@ -56,6 +56,15 @@ static __init void uefi_blacklist_binary(const char *source, } /* + * 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; } |