From 437a88a58371aa4a3ea01dbe194337e3f97c4b29 Mon Sep 17 00:00:00 2001 From: David Gstir Date: Sun, 15 Nov 2015 17:14:41 +0100 Subject: [PATCH] crypto: nx - Fix timing leak in GCM and CCM decryption commit cb8affb55c7e64816f3effcd9b2fc3268c016fac upstream. Using non-constant time memcmp() makes the verification of the authentication tag in the decrypt path vulnerable to timing attacks. Fix this by using crypto_memneq() instead. Signed-off-by: David Gstir Signed-off-by: Herbert Xu [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques --- drivers/crypto/nx/nx-aes-ccm.c | 2 +- drivers/crypto/nx/nx-aes-gcm.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/crypto/nx/nx-aes-ccm.c b/drivers/crypto/nx/nx-aes-ccm.c index 5ecd4c2414aa8..b1679db09de2d 100644 --- a/drivers/crypto/nx/nx-aes-ccm.c +++ b/drivers/crypto/nx/nx-aes-ccm.c @@ -411,7 +411,7 @@ static int ccm_nx_decrypt(struct aead_request *req, processed += to_process; } while (processed < nbytes); - rc = memcmp(csbcpb->cpb.aes_ccm.out_pat_or_mac, priv->oauth_tag, + rc = crypto_memneq(csbcpb->cpb.aes_ccm.out_pat_or_mac, priv->oauth_tag, authsize) ? -EBADMSG : 0; out: spin_unlock_irqrestore(&nx_ctx->lock, irq_flags); diff --git a/drivers/crypto/nx/nx-aes-gcm.c b/drivers/crypto/nx/nx-aes-gcm.c index 025d9a8d5b190..dd4431ea1376e 100644 --- a/drivers/crypto/nx/nx-aes-gcm.c +++ b/drivers/crypto/nx/nx-aes-gcm.c @@ -415,7 +415,7 @@ mac: scatterwalk_map_and_copy(itag, req->src, nbytes, crypto_aead_authsize(crypto_aead_reqtfm(req)), SCATTERWALK_FROM_SG); - rc = memcmp(itag, otag, + rc = crypto_memneq(itag, otag, crypto_aead_authsize(crypto_aead_reqtfm(req))) ? -EBADMSG : 0; } -- 2.47.3