From: Lars Persson <lars.persson@axis.com>
Date: Wed, 23 Jan 2019 11:59:45 +0000 (+0100)
Subject: crypto: axis - use a constant time tag compare
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=5997a245c77b754fb8ef807043066fcfde64858c;p=openwrt%2Fstaging%2Fblogic.git

crypto: axis - use a constant time tag compare

Avoid plain memcmp() on the AEAD tag value as this could leak
information through a timing side channel.

Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

diff --git a/drivers/crypto/axis/artpec6_crypto.c b/drivers/crypto/axis/artpec6_crypto.c
index 5089ad2c49f9..109efab6a9df 100644
--- a/drivers/crypto/axis/artpec6_crypto.c
+++ b/drivers/crypto/axis/artpec6_crypto.c
@@ -2201,9 +2201,9 @@ static void artpec6_crypto_complete_aead(struct crypto_async_request *req)
 				   areq->assoclen + areq->cryptlen -
 				   authsize);
 
-		if (memcmp(req_ctx->decryption_tag,
-			   input_tag,
-			   authsize)) {
+		if (crypto_memneq(req_ctx->decryption_tag,
+				  input_tag,
+				  authsize)) {
 			pr_debug("***EBADMSG:\n");
 			print_hex_dump_debug("ref:", DUMP_PREFIX_ADDRESS, 32, 1,
 					     input_tag, authsize, true);