From a9fd1795fee69a9d384ead855e045edd5a035bb5 Mon Sep 17 00:00:00 2001 From: Cfir Cohen Date: Tue, 2 Jul 2019 10:32:56 -0700 Subject: [PATCH] crypto: ccp/gcm - use const time tag comparison. commit 538a5a072e6ef04377b180ee9b3ce5bae0a85da4 upstream. Avoid leaking GCM tag through timing side channel. Fixes: 36cf515b9bbe ("crypto: ccp - Enable support for AES GCM on v5 CCPs") Cc: # v4.12+ Signed-off-by: Cfir Cohen Acked-by: Gary R Hook Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- drivers/crypto/ccp/ccp-ops.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/crypto/ccp/ccp-ops.c b/drivers/crypto/ccp/ccp-ops.c index 5df77e4..e212bad 100644 --- a/drivers/crypto/ccp/ccp-ops.c +++ b/drivers/crypto/ccp/ccp-ops.c @@ -853,7 +853,8 @@ static int ccp_run_aes_gcm_cmd(struct ccp_cmd_queue *cmd_q, if (ret) goto e_tag; - ret = memcmp(tag.address, final_wa.address, AES_BLOCK_SIZE); + ret = crypto_memneq(tag.address, final_wa.address, + AES_BLOCK_SIZE) ? -EBADMSG : 0; ccp_dm_free(&tag); } -- 2.7.4