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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2016-09-13 11:48:52 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2016-09-13 13:44:59 +0300
commitf82e90b28654804ab72881d577d87c3d5c65e2bc (patch)
tree1e7f834cc0b8e1275394ba1910b6622d20bf47c5 /arch/arm/crypto
parentacdb04d0b36769b3e05990c488dc74d8b7ac8060 (diff)
downloadlinux-f82e90b28654804ab72881d577d87c3d5c65e2bc.tar.xz
crypto: arm/aes-ctr - fix NULL dereference in tail processing
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") Cc: stable@vger.kernel.org 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>
Diffstat (limited to 'arch/arm/crypto')
-rw-r--r--arch/arm/crypto/aes-ce-glue.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/crypto/aes-ce-glue.c b/arch/arm/crypto/aes-ce-glue.c
index da3c0428507b..aef022a87c53 100644
--- 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_desc *desc, struct scatterlist *dst,
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];