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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2016-09-13 09:48:52 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2016-09-13 18:44:59 +0800 |
| commit | f82e90b28654804ab72881d577d87c3d5c65e2bc (patch) | |
| tree | 1e7f834cc0b8e1275394ba1910b6622d20bf47c5 /arch/arm/crypto | |
| parent | acdb04d0b36769b3e05990c488dc74d8b7ac8060 (diff) | |
| download | linux-f82e90b28654804ab72881d577d87c3d5c65e2bc.tar.bz2 | |
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.c | 2 |
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]; |