[PATCH] rsa-pkcs1pad: use constant time memory comparison for MACs

[Jason A. Donenfeld]

Otherwise, we enable all sorts of forgeries via timing attack.

Signed-off-by: Jason A. Donenfeld <ja...@zx2c4.com>
Suggested-by: Stephan Müller <smuel...@chronox.de>
Cc: sta...@vger.kernel.org
Cc: Herbert Xu <herb...@gondor.apana.org.au>
Cc: linux-crypto@vger.kernel.org
---
 crypto/rsa-pkcs1pad.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index 8baab4307f7b..7830d304dff6 100644
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -496,7 +496,7 @@ static int pkcs1pad_verify_complete(struct akcipher_request 
*req, int err)
                goto done;
        pos++;
 
-       if (memcmp(out_buf + pos, digest_info->data, digest_info->size))
+       if (crypto_memneq(out_buf + pos, digest_info->data, digest_info->size))
                goto done;
 
        pos += digest_info->size;
-- 
2.13.1