crypto: gcm - Fix IV buffer size in crypto_gcm_setkey

commit 50d2e6dc upstream.

The cipher block size for GCM is 16 bytes, and thus the CTR transform
used in crypto_gcm_setkey() will also expect a 16-byte IV. However,
the code currently reserves only 8 bytes for the IV, causing
an out-of-bounds access in the CTR transform. This patch fixes
the issue by setting the size of the IV buffer to 16 bytes.

Fixes: 84c91152 ("[CRYPTO] gcm: Add support for async ciphers")
Signed-off-by: Ondrej Mosnacek <omosnacek@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

crypto/gcm.c

@@ -103,7 +103,7 @@ static int crypto_gcm_setkey(struct crypto_aead *aead, const u8 *key,
 	struct crypto_ablkcipher *ctr = ctx->ctr;
 	struct {
 		be128 hash;
-		u8 iv[8];
+		u8 iv[16];
 
 		struct crypto_gcm_setkey_result result;