[patch added to 3.12-stable] crypto: gcm - Filter out async ghash if necessary

From: Herbert Xu <herbert@gondor.apana.org.au>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.

===============

commit b30bdfa86431afbafe15284a3ad5ac19b49b88e3 upstream.

As it is if you ask for a sync gcm you may actually end up with
an async one because it does not filter out async implementations
of ghash.

This patch fixes this by adding the necessary filter when looking
for ghash.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jiri Slaby <redacted>
---
 crypto/gcm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/crypto/gcm.c b/crypto/gcm.c
index f0bd00b15f26..d2a0f7371cf0 100644
--- a/crypto/gcm.c
+++ b/crypto/gcm.c

@@ -716,7 +716,9 @@ static struct crypto_instance *crypto_gcm_alloc_common(struct rtattr **tb,
 
 	ghash_alg = crypto_find_alg(ghash_name, &crypto_ahash_type,
 				    CRYPTO_ALG_TYPE_HASH,
-				    CRYPTO_ALG_TYPE_AHASH_MASK);
+				    CRYPTO_ALG_TYPE_AHASH_MASK |
+				    crypto_requires_sync(algt->type,
+							 algt->mask));
 	if (IS_ERR(ghash_alg))
 		return ERR_CAST(ghash_alg);
 

-- 
2.9.3