kernel/linux.git/certs/blacklist.c, branch v6.1.174

certs: Move load_certificate_list() to be with the asymmetric keys code

2022-06-21T15:05:06+00:00

Move load_certificate_list(), which loads a series of binary X.509 certificates from a blob and inserts them as keys into a keyring, to be with the asymmetric keys code that it drives. This makes it easier to add FIPS selftest code in which we need to load up a private keyring for the tests to use. Signed-off-by: David Howells Reviewed-by: Simo Sorce Reviewed-by: Herbert Xu cc: keyrings@vger.kernel.org cc: linux-crypto@vger.kernel.org Link: https://lore.kernel.org/r/165515742145.1554877.13488098107542537203.stgit@warthog.procyon.org.uk/

certs: Explain the rationale to call panic()

2022-05-23T15:47:49+00:00

The blacklist_init() function calls panic() for memory allocation errors. This change documents the reason why we don't return -ENODEV. Link: https://lore.kernel.org/r/20220322111323.542184-2-mic@digikod.net Link: https://lore.kernel.org/r/YjeW2r6Wv55Du0bJ@iki.fi Suggested-by: Paul Moore Reviewed-by: Paul Moore Reviewed-by: Jarkko Sakkinen Signed-off-by: Mickaël Salaün Signed-off-by: Jarkko Sakkinen

certs: Allow root user to append signed hashes to the blacklist keyring

2022-05-23T15:47:49+00:00

Add a kernel option SYSTEM_BLACKLIST_AUTH_UPDATE to enable the root user to dynamically add new keys to the blacklist keyring. This enables to invalidate new certificates, either from being loaded in a keyring, or from being trusted in a PKCS#7 certificate chain. This also enables to add new file hashes to be denied by the integrity infrastructure. Being able to untrust a certificate which could have normaly been trusted is a sensitive operation. This is why adding new hashes to the blacklist keyring is only allowed when these hashes are signed and vouched by the builtin trusted keyring. A blacklist hash is stored as a key description. The PKCS#7 signature of this description must be provided as the key payload. Marking a certificate as untrusted should be enforced while the system is running. It is then forbiden to remove such blacklist keys. Update blacklist keyring, blacklist key and revoked certificate access rights: * allows the root user to search for a specific blacklisted hash, which make sense because the descriptions are already viewable; * forbids key update (blacklist and asymmetric ones); * restricts kernel rights on the blacklist keyring to align with the root user rights. See help in tools/certs/print-cert-tbs-hash.sh . Cc: David Howells Cc: David Woodhouse Cc: Eric Snowberg Cc: Jarkko Sakkinen Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20210712170313.884724-6-mic@digikod.net Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen

certs: Make blacklist_vet_description() more strict

2022-05-23T15:47:49+00:00

Before exposing this new key type to user space, make sure that only meaningful blacklisted hashes are accepted. This is also checked for builtin blacklisted hashes, but a following commit make sure that the user will notice (at built time) and will fix the configuration if it already included errors. Check that a blacklist key description starts with a valid prefix and then a valid hexadecimal string. Cc: David Howells Cc: David Woodhouse Cc: Eric Snowberg Signed-off-by: Mickaël Salaün Reviewed-by: Jarkko Sakkinen Link: https://lore.kernel.org/r/20210712170313.884724-4-mic@digikod.net Signed-off-by: Jarkko Sakkinen

certs: Factor out the blacklist hash creation

2022-05-23T15:47:49+00:00

Factor out the blacklist hash creation with the get_raw_hash() helper. This also centralize the "tbs" and "bin" prefixes and make them private, which help to manage them consistently. Cc: David Howells Cc: David S. Miller Cc: David Woodhouse Cc: Eric Snowberg Cc: Herbert Xu Cc: Jarkko Sakkinen Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20210712170313.884724-5-mic@digikod.net Signed-off-by: Jarkko Sakkinen

certs: Add ability to preload revocation certs

2021-03-11T16:33:49+00:00

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 Acked-by: Jarkko Sakkinen Signed-off-by: David Howells cc: Randy Dunlap cc: keyrings@vger.kernel.org Link: https://lore.kernel.org/r/e1c15c74-82ce-3a69-44de-a33af9b320ea@infradead.org/ [1] Link: https://lore.kernel.org/r/20210303034418.106762-1-eric.snowberg@oracle.com/ [2] Link: https://lore.kernel.org/r/20210304175030.184131-1-eric.snowberg@oracle.com/ [3] Link: https://lore.kernel.org/r/20200930201508.35113-3-eric.snowberg@oracle.com/ Link: https://lore.kernel.org/r/20210122181054.32635-4-eric.snowberg@oracle.com/ # 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/161529606657.163428.3340689182456495390.stgit@warthog.procyon.org.uk/ # v3

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]

certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID

2021-01-21T16:16:10+00:00

Align with the new macros and add appropriate include files. Signed-off-by: Mickaël Salaün Signed-off-by: David Howells Cc: David Woodhouse

certs: Fix blacklist flag type confusion

2021-01-21T16:16:10+00:00

KEY_FLAG_KEEP is not meant to be passed to keyring_alloc() or key_alloc(), as these only take KEY_ALLOC_* flags. KEY_FLAG_KEEP has the same value as KEY_ALLOC_BYPASS_RESTRICTION, but fortunately only key_create_or_update() uses it. LSMs using the key_alloc hook don't check that flag. KEY_FLAG_KEEP is then ignored but fortunately (again) the root user cannot write to the blacklist keyring, so it is not possible to remove a key/hash from it. Fix this by adding a KEY_ALLOC_SET_KEEP flag that tells key_alloc() to set KEY_FLAG_KEEP on the new key. blacklist_init() can then, correctly, pass this to keyring_alloc(). We can also use this in ima_mok_init() rather than setting the flag manually. Note that this doesn't fix an observable bug with the current implementation but it is required to allow addition of new hashes to the blacklist in the future without making it possible for them to be removed. Fixes: 734114f8782f ("KEYS: Add a system blacklist keyring") Reported-by: Mickaël Salaün Signed-off-by: David Howells cc: Mickaël Salaün cc: Mimi Zohar Cc: David Woodhouse

certs: Fix blacklisted hexadecimal hash string check

2021-01-21T16:16:10+00:00

When looking for a blacklisted hash, bin2hex() is used to transform a binary hash to an ascii (lowercase) hexadecimal string. This string is then search for in the description of the keys from the blacklist keyring. When adding a key to the blacklist keyring, blacklist_vet_description() checks the hash prefix and the hexadecimal string, but not that this string is lowercase. It is then valid to set hashes with uppercase hexadecimal, which will be silently ignored by the kernel. Add an additional check to blacklist_vet_description() to check that hexadecimal strings are in lowercase. Signed-off-by: Mickaël Salaün Signed-off-by: David Howells Reviewed-by: Ben Boeckel Cc: David Woodhouse