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authorEric Biggers <ebiggers@google.com>2023-07-05 14:17:19 -0700
committerEric Biggers <ebiggers@google.com>2023-07-11 22:49:18 -0700
commit5d37a1198068b099de47073411efc087d1b555ca (patch)
tree39624be68b704374ef11cfb3f53bc392a4143497
parent06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5 (diff)
fsverity: explicitly check that there is no algorithm 0
Since libfsverity and some other code would break if 0 is ever allocated as an FS_VERITY_HASH_ALG_* value, make fsverity_check_hash_algs() explicitly check that there is no algorithm 0. Link: https://lore.kernel.org/r/20230705211719.37713-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
-rw-r--r--fs/verity/hash_algs.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/verity/hash_algs.c b/fs/verity/hash_algs.c
index c598d2035476..6b08b1d9a7d7 100644
--- a/fs/verity/hash_algs.c
+++ b/fs/verity/hash_algs.c
@@ -226,6 +226,14 @@ void __init fsverity_check_hash_algs(void)
if (!alg->name)
continue;
+ /*
+ * 0 must never be allocated as an FS_VERITY_HASH_ALG_* value,
+ * as it is reserved for users that use 0 to mean unspecified or
+ * a default value. fs/verity/ itself doesn't care and doesn't
+ * have a default algorithm, but some users make use of this.
+ */
+ BUG_ON(i == 0);
+
BUG_ON(alg->digest_size > FS_VERITY_MAX_DIGEST_SIZE);
/*