fsverity: simplify fsverity_get_digest()
Instead of looking up the algorithm by name in hash_algo_name[] to get
its hash_algo ID, just store the hash_algo ID in the fsverity_hash_alg
struct. Verify at boot time that every fsverity_hash_alg has a valid
hash_algo ID with matching digest size.
Remove an unnecessary memset() of the whole digest array to 0 before the
digest is copied into it.
Finally, remove the pr_debug statement. There is already a pr_debug for
the fsverity digest when the file is opened.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20221129045139.69803-1-ebiggers@kernel.org
diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
index dbe1ce5..c7fcb855 100644
--- a/fs/verity/fsverity_private.h
+++ b/fs/verity/fsverity_private.h
@@ -32,6 +32,11 @@ struct fsverity_hash_alg {
unsigned int digest_size; /* digest size in bytes, e.g. 32 for SHA-256 */
unsigned int block_size; /* block size in bytes, e.g. 64 for SHA-256 */
mempool_t req_pool; /* mempool with a preallocated hash request */
+ /*
+ * The HASH_ALGO_* constant for this algorithm. This is different from
+ * FS_VERITY_HASH_ALG_*, which uses a different numbering scheme.
+ */
+ enum hash_algo algo_id;
};
/* Merkle tree parameters: hash algorithm, initial hash state, and topology */
