[PATCH 3.19.y-ckt 091/128] crypto: nx - Fix timing leak in GCM and CCM decryption
From: Kamal Mostafa
Date: Wed Dec 16 2015 - 12:54:04 EST
3.19.8-ckt12 -stable review patch. If anyone has any objections, please let me know.
------------------
From: David Gstir <david@xxxxxxxxxxxxx>
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 <david@xxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
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 67f8081..40992a2 100644
--- a/drivers/crypto/nx/nx-aes-ccm.c
+++ b/drivers/crypto/nx/nx-aes-ccm.c
@@ -412,7 +412,7 @@ 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 88c5624..ae4561d 100644
--- a/drivers/crypto/nx/nx-aes-gcm.c
+++ b/drivers/crypto/nx/nx-aes-gcm.c
@@ -423,7 +423,7 @@ 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;
}
--
1.9.1
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