Patch "crypto: arm/aes-ctr - fix NULL dereference in tail processing" has been added to the 4.7-stable tree

Patch "crypto: arm/aes-ctr - fix NULL dereference in tail processing" has been added to the 4.7-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    crypto: arm/aes-ctr - fix NULL dereference in tail processing

to the 4.7-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-arm-aes-ctr-fix-null-dereference-in-tail-processing.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From f82e90b28654804ab72881d577d87c3d5c65e2bc Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Tue, 13 Sep 2016 09:48:52 +0100
Subject: crypto: arm/aes-ctr - fix NULL dereference in tail processing

From: Ard Biesheuvel <ard.biesheuvel@linaro.org>

commit f82e90b28654804ab72881d577d87c3d5c65e2bc upstream.

The AES-CTR glue code avoids calling into the blkcipher API for the
tail portion of the walk, by comparing the remainder of walk.nbytes
modulo AES_BLOCK_SIZE with the residual nbytes, and jumping straight
into the tail processing block if they are equal. This tail processing
block checks whether nbytes != 0, and does nothing otherwise.

However, in case of an allocation failure in the blkcipher layer, we
may enter this code with walk.nbytes == 0, while nbytes > 0. In this
case, we should not dereference the source and destination pointers,
since they may be NULL. So instead of checking for nbytes != 0, check
for (walk.nbytes % AES_BLOCK_SIZE) != 0, which implies the former in
non-error conditions.

Fixes: 86464859cc77 ("crypto: arm - AES in ECB/CBC/CTR/XTS modes using ARMv8 Crypto Extensions")
Reported-by: xiakaixu <xiakaixu@huawei.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm/crypto/aes-ce-glue.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm/crypto/aes-ce-glue.c
+++ b/arch/arm/crypto/aes-ce-glue.c
@@ -284,7 +284,7 @@ static int ctr_encrypt(struct blkcipher_
 		err = blkcipher_walk_done(desc, &walk,
 					  walk.nbytes % AES_BLOCK_SIZE);
 	}
-	if (nbytes) {
+	if (walk.nbytes % AES_BLOCK_SIZE) {
 		u8 *tdst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 		u8 *tsrc = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 		u8 __aligned(8) tail[AES_BLOCK_SIZE];


Patches currently in stable-queue which might be from ard.biesheuvel@linaro.org are

queue-4.7/crypto-arm64-aes-ctr-fix-null-dereference-in-tail-processing.patch
queue-4.7/crypto-arm-aes-ctr-fix-null-dereference-in-tail-processing.patch
queue-4.7/crypto-skcipher-fix-blkcipher-walk-oom-crash.patch