From: Cfir Cohen <cfir@xxxxxxxxxx>
commit 538a5a072e6ef04377b180ee9b3ce5bae0a85da4 upstream.
Avoid leaking GCM tag through timing side channel.
Fixes: 36cf515b9bbe ("crypto: ccp - Enable support for AES GCM on v5 CCPs")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.12+
Signed-off-by: Cfir Cohen <cfir@xxxxxxxxxx>
Acked-by: Gary R Hook <ghook@xxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/crypto/ccp/ccp-ops.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/crypto/ccp/ccp-ops.c
+++ b/drivers/crypto/ccp/ccp-ops.c
@@ -850,7 +850,8 @@ static int ccp_run_aes_gcm_cmd(struct cc
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);
}
