crypto: hash - annotate algorithms taking optional key

We need to consistently enforce that keyed hashes cannot be used without
setting the key.  To do this we need a reliable way to determine whether
a given hash algorithm is keyed or not.  AF_ALG currently does this by
checking for the presence of a ->setkey() method.  However, this is
actually slightly broken because the CRC-32 algorithms implement
->setkey() but can also be used without a key.  (The CRC-32 "key" is not
actually a cryptographic key but rather represents the initial state.
If not overridden, then a default initial state is used.)

Prepare to fix this by introducing a flag CRYPTO_ALG_OPTIONAL_KEY which
indicates that the algorithm has a ->setkey() method, but it is not
required to be called.  Then set it on all the CRC-32 algorithms.

The same also applies to the Adler-32 implementation in Lustre.

Also, the cryptd and mcryptd templates have to pass through the flag
from their underlying algorithm.

Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/crypto/bfin_crc.c b/drivers/crypto/bfin_crc.c
index a118b9bed669..bfbf8bf77f03 100644
--- a/drivers/crypto/bfin_crc.c
+++ b/drivers/crypto/bfin_crc.c
@@ -494,7 +494,8 @@ static struct ahash_alg algs = {
 		.cra_driver_name	= DRIVER_NAME,
 		.cra_priority		= 100,
 		.cra_flags		= CRYPTO_ALG_TYPE_AHASH |
-						CRYPTO_ALG_ASYNC,
+						CRYPTO_ALG_ASYNC |
+						CRYPTO_ALG_OPTIONAL_KEY,
 		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(struct bfin_crypto_crc_ctx),
 		.cra_alignmask		= 3,