From: Mickaël Salaün <m...@linux.microsoft.com>

Add a new DM_VERITY_VERIFY_ROOTHASH_SIG_SECONDARY_KEYRING configuration
to enable dm-verity signatures to be verified against the secondary
trusted keyring.  This allows certificate updates without kernel update
and reboot, aligning with module and kernel (kexec) signature
verifications.

Signed-off-by: Mickaël Salaün <m...@linux.microsoft.com>
Cc: Jaskaran Khurana <jaskarankhur...@linux.microsoft.com>
Cc: Mike Snitzer <snit...@redhat.com>
Cc: Milan Broz <gmazyl...@gmail.com>
---
 drivers/md/Kconfig                | 13 ++++++++++++-
 drivers/md/dm-verity-verify-sig.c |  9 +++++++--
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 30ba3573626c..63870fdfe8ce 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -530,11 +530,22 @@ config DM_VERITY_VERIFY_ROOTHASH_SIG
        bool "Verity data device root hash signature verification support"
        depends on DM_VERITY
        select SYSTEM_DATA_VERIFICATION
-         help
+       ---help---
          Add ability for dm-verity device to be validated if the
          pre-generated tree of cryptographic checksums passed has a pkcs#7
          signature file that can validate the roothash of the tree.
 
+         By default, rely on the builtin trusted keyring.
+
+         If unsure, say N.
+
+config DM_VERITY_VERIFY_ROOTHASH_SIG_SECONDARY_KEYRING
+       bool "Verity data device root hash signature verification with 
secondary keyring"
+       depends on DM_VERITY_VERIFY_ROOTHASH_SIG
+       depends on SECONDARY_TRUSTED_KEYRING
+       ---help---
+         Rely on the secondary trusted keyring to verify dm-verity signatures.
+
          If unsure, say N.
 
 config DM_VERITY_FEC
diff --git a/drivers/md/dm-verity-verify-sig.c 
b/drivers/md/dm-verity-verify-sig.c
index 614e43db93aa..29385dc470d5 100644
--- a/drivers/md/dm-verity-verify-sig.c
+++ b/drivers/md/dm-verity-verify-sig.c
@@ -119,8 +119,13 @@ int verity_verify_root_hash(const void *root_hash, size_t 
root_hash_len,
        }
 
        ret = verify_pkcs7_signature(root_hash, root_hash_len, sig_data,
-                               sig_len, NULL, VERIFYING_UNSPECIFIED_SIGNATURE,
-                               NULL, NULL);
+                               sig_len,
+#ifdef CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG_SECONDARY_KEYRING
+                               VERIFY_USE_SECONDARY_KEYRING,
+#else
+                               NULL,
+#endif
+                               VERIFYING_UNSPECIFIED_SIGNATURE, NULL, NULL);
 
        return ret;
 }
-- 
2.28.0

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