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, 0 deletions

diff --git a/arch/arm/crypto/crc32-ce-glue.c b/arch/arm/crypto/crc32-ce-glue.c
index 1b0e0e86ee9c..96e62ec105d0 100644
--- a/arch/arm/crypto/crc32-ce-glue.c
+++ b/arch/arm/crypto/crc32-ce-glue.c
@@ -188,6 +188,7 @@ static struct shash_alg crc32_pmull_algs[] = { {
 	.base.cra_name		= "crc32",
 	.base.cra_driver_name	= "crc32-arm-ce",
 	.base.cra_priority	= 200,
+	.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 	.base.cra_blocksize	= 1,
 	.base.cra_module	= THIS_MODULE,
 }, {
@@ -203,6 +204,7 @@ static struct shash_alg crc32_pmull_algs[] = { {
 	.base.cra_name		= "crc32c",
 	.base.cra_driver_name	= "crc32c-arm-ce",
 	.base.cra_priority	= 200,
+	.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 	.base.cra_blocksize	= 1,
 	.base.cra_module	= THIS_MODULE,
 } };