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| author | Jaskaran Khurana <jaskarankhurana@linux.microsoft.com> | 2019-07-17 17:46:15 -0700 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2019-08-23 10:13:14 -0400 |
| commit | 88cd3e6cfac915f50f7aa7b699bdf053afec866e (patch) | |
| tree | a7fe35abcd39a0f98375d77a0a8e43d2bec60092 /Documentation/admin-guide/device-mapper | |
| parent | 39d13a1ac41dc8254f484fcd21af7ff05e316fad (diff) | |
| download | linux-88cd3e6cfac915f50f7aa7b699bdf053afec866e.tar.bz2 | |
dm verity: add root hash pkcs#7 signature verification
The verification is to support cases where the root hash is not secured
by Trusted Boot, UEFI Secureboot or similar technologies.
One of the use cases for this is for dm-verity volumes mounted after
boot, the root hash provided during the creation of the dm-verity volume
has to be secure and thus in-kernel validation implemented here will be
used before we trust the root hash and allow the block device to be
created.
The signature being provided for verification must verify the root hash
and must be trusted by the builtin keyring for verification to succeed.
The hash is added as a key of type "user" and the description is passed
to the kernel so it can look it up and use it for verification.
Adds CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG which can be turned on if root
hash verification is needed.
Kernel commandline dm_verity module parameter 'require_signatures' will
indicate whether to force root hash signature verification (for all dm
verity volumes).
Signed-off-by: Jaskaran Khurana <jaskarankhurana@linux.microsoft.com>
Tested-and-Reviewed-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'Documentation/admin-guide/device-mapper')
| -rw-r--r-- | Documentation/admin-guide/device-mapper/verity.rst | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/admin-guide/device-mapper/verity.rst b/Documentation/admin-guide/device-mapper/verity.rst index a4d1c1476d72..bb02caa45289 100644 --- a/Documentation/admin-guide/device-mapper/verity.rst +++ b/Documentation/admin-guide/device-mapper/verity.rst @@ -125,6 +125,13 @@ check_at_most_once blocks, and a hash block will not be verified any more after all the data blocks it covers have been verified anyway. +root_hash_sig_key_desc <key_description> + This is the description of the USER_KEY that the kernel will lookup to get + the pkcs7 signature of the roothash. The pkcs7 signature is used to validate + the root hash during the creation of the device mapper block device. + Verification of roothash depends on the config DM_VERITY_VERIFY_ROOTHASH_SIG + being set in the kernel. + Theory of operation =================== |