crypto: talitos - Fix timing leak in ESP ICV verification

commit 79960943 upstream.

Using non-constant time memcmp() makes the verification of the authentication
tag in the decrypt path vulnerable to timing attacks. Fix this by using
crypto_memneq() instead.
Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/crypto/talitos.c

@@ -1015,7 +1015,7 @@ static void ipsec_esp_decrypt_swauth_done(struct device *dev,
 		} else
 			oicv = (char *)&edesc->link_tbl[0];
 
-		err = memcmp(oicv, icv, authsize) ? -EBADMSG : 0;
+		err = crypto_memneq(oicv, icv, authsize) ? -EBADMSG : 0;
 	}
 
 	kfree(edesc);