linux.git/security/integrity/platform_certs/keyring_handler.c, branch v5.18

integrity: Only use machine keyring when uefi_check_trust_mok_keys is true

2022-03-08T11:55:52+00:00

With the introduction of uefi_check_trust_mok_keys, it signifies the end-
user wants to trust the machine keyring as trusted keys.  If they have
chosen to trust the machine keyring, load the qualifying keys into it
during boot, then link it to the secondary keyring .  If the user has not
chosen to trust the machine keyring, it will be empty and not linked to
the secondary keyring.

Signed-off-by: Eric Snowberg 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

integrity: add new keyring handler for mok keys

2022-03-08T11:55:52+00:00

Currently both Secure Boot DB and Machine Owner Keys (MOK) go through
the same keyring handler (get_handler_for_db). With the addition of the
new machine keyring, the end-user may choose to trust MOK keys.

Introduce a new keyring handler specific for MOK keys.  If MOK keys are
trusted by the end-user, use the new keyring handler instead.

Signed-off-by: Eric Snowberg 
Reviewed-by: Mimi Zohar 
Reviewed-by: Jarkko Sakkinen 
Tested-by: Mimi Zohar 
Signed-off-by: Jarkko Sakkinen

integrity: Fix warning about missing prototypes

2022-03-08T11:55:52+00:00

make W=1 generates the following warning in keyring_handler.c

security/integrity/platform_certs/keyring_handler.c:71:30: warning: no previous prototype for get_handler_for_db [-Wmissing-prototypes]
 __init efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type)
                              ^~~~~~~~~~~~~~~~~~
security/integrity/platform_certs/keyring_handler.c:82:30: warning: no previous prototype for get_handler_for_dbx [-Wmissing-prototypes]
 __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type)
                              ^~~~~~~~~~~~~~~~~~~
Add the missing prototypes by including keyring_handler.h.

Reported-by: kernel test robot 
Signed-off-by: Eric Snowberg 
Reviewed-by: Mimi Zohar 
Reviewed-by: Jarkko Sakkinen 
Tested-by: Mimi Zohar 
Signed-off-by: Jarkko Sakkinen

certs: Add EFI_CERT_X509_GUID support for dbx entries

2021-03-11T16:31:28+00:00

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 
Signed-off-by: David Howells 
Reviewed-by: Jarkko Sakkinen 
cc: Randy Dunlap 
cc: Mickaël Salaün 
cc: Arnd Bergmann 
cc: keyrings@vger.kernel.org
Link: https://lore.kernel.org/r/20200901165143.10295-1-eric.snowberg@oracle.com/ # rfc
Link: https://lore.kernel.org/r/20200909172736.73003-1-eric.snowberg@oracle.com/ # v2
Link: https://lore.kernel.org/r/20200911182230.62266-1-eric.snowberg@oracle.com/ # v3
Link: https://lore.kernel.org/r/20200916004927.64276-1-eric.snowberg@oracle.com/ # v4
Link: https://lore.kernel.org/r/20210122181054.32635-2-eric.snowberg@oracle.com/ # 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/bc2c24e3-ed68-2521-0bf4-a1f6be4a895d@infradead.org/ [1]
Link: https://lore.kernel.org/r/20210225125638.1841436-1-arnd@kernel.org/ [2]

x86/efi: move common keyring handler functions to new file

2019-11-12T13:33:23+00:00

The handlers to add the keys to the .platform keyring and blacklisted
hashes to the .blacklist keyring is common for both the uefi and powerpc
mechanisms of loading the keys/hashes from the firmware.

This patch moves the common code from load_uefi.c to keyring_handler.c

Signed-off-by: Nayna Jain 
Acked-by: Mimi Zohar 
Signed-off-by: Eric Richter 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/1573441836-3632-4-git-send-email-nayna@linux.ibm.com