This is a note to let you know that I've just added the patch titled
crypto: ccm - preserve the IV buffer
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
crypto-ccm-preserve-the-iv-buffer.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 441f99c90497e15aa3ad1dbabd56187e29614348 Mon Sep 17 00:00:00 2001
From: Romain Izard <romain.izard.pro@xxxxxxxxx>
Date: Tue, 31 Oct 2017 15:42:35 +0100
Subject: crypto: ccm - preserve the IV buffer
From: Romain Izard <romain.izard.pro@xxxxxxxxx>
commit 441f99c90497e15aa3ad1dbabd56187e29614348 upstream.
The IV buffer used during CCM operations is used twice, during both the
hashing step and the ciphering step.
When using a hardware accelerator that updates the contents of the IV
buffer at the end of ciphering operations, the value will be modified.
In the decryption case, the subsequent setup of the hashing algorithm
will interpret the updated IV instead of the original value, which can
lead to out-of-bounds writes.
Reuse the idata buffer, only used in the hashing step, to preserve the
IV's value during the ciphering step in the decryption case.
Signed-off-by: Romain Izard <romain.izard.pro@xxxxxxxxx>
Reviewed-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
crypto/ccm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/crypto/ccm.c
+++ b/crypto/ccm.c
@@ -413,7 +413,7 @@ static int crypto_ccm_decrypt(struct aea
unsigned int cryptlen = req->cryptlen;
u8 *authtag = pctx->auth_tag;
u8 *odata = pctx->odata;
- u8 *iv = req->iv;
+ u8 *iv = pctx->idata;
int err;
cryptlen -= authsize;
@@ -429,6 +429,8 @@ static int crypto_ccm_decrypt(struct aea
if (req->src != req->dst)
dst = pctx->dst;
+ memcpy(iv, req->iv, 16);
+
skcipher_request_set_tfm(skreq, ctx->ctr);
skcipher_request_set_callback(skreq, pctx->flags,
crypto_ccm_decrypt_done, req);
Patches currently in stable-queue which might be from romain.izard.pro@xxxxxxxxx are
queue-4.9/crypto-ccm-preserve-the-iv-buffer.patch