From: Cfir Cohen cfir@google.com
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@vger.kernel.org # v4.12+ Signed-off-by: Cfir Cohen cfir@google.com Acked-by: Gary R Hook ghook@amd.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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); }