crypto: ahash - ensure statesize is non-zero

commit 8996eafdcbad149ac0f772fb1649fbb75c482a6a upstream.

Unlike shash algorithms, ahash drivers must implement export
and import as their descriptors may contain hardware state and
cannot be exported as is.  Unfortunately some ahash drivers did
not provide them and end up causing crashes with algif_hash.

This patch adds a check to prevent these drivers from registering
ahash algorithms until they are fixed.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Zefan Li <lizefan@huawei.com>

diff --git a/crypto/ahash.c b/crypto/ahash.c
index 0ec05feea43814d692ca9589244496891f6a7819..58241912a07f2ad7b9408b9c85001478c81daa20 100644 (file)
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -462,7 +462,8 @@ static int ahash_prepare_alg(struct ahash_alg *alg)
        struct crypto_alg *base = &alg->halg.base;
 
        if (alg->halg.digestsize > PAGE_SIZE / 8 ||
-           alg->halg.statesize > PAGE_SIZE / 8)
+           alg->halg.statesize > PAGE_SIZE / 8 ||
+           alg->halg.statesize == 0)
                return -EINVAL;
 
        base->cra_type = &crypto_ahash_type;