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crypto: skcipher - Fix blkcipher walk OOM crash

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commit acdb04d0b36769b3e05990c488dc74d8b7ac8060 upstream.

When we need to allocate a temporary blkcipher_walk_next and it
fails, the code is supposed to take the slow path of processing
the data block by block.  However, due to an unrelated change
we instead end up dereferencing the NULL pointer.

This patch fixes it by moving the unrelated bsize setting out
of the way so that we enter the slow path as inteded.

Fixes: 7607bd8ff03b ("[CRYPTO] blkcipher: Added blkcipher_walk_virt_block")
Reported-by: xiakaixu <xiakaixu@huawei.com>
Reported-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Herbert Xu 2016-09-13 14:43:29 +08:00 committed by Greg Kroah-Hartman
parent 9246fd26f9
commit 1c95a8a481
1 changed files with 2 additions and 1 deletions
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3
crypto/blkcipher.c
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@ -234,6 +234,8 @@ static int blkcipher_walk_next(struct blkcipher_desc *desc,
return blkcipher_walk_done(desc, walk, -EINVAL);
}
bsize = min(walk->walk_blocksize, n);
walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
BLKCIPHER_WALK_DIFF);
if (!scatterwalk_aligned(&walk->in, walk->alignmask) ||
@ -246,7 +248,6 @@ static int blkcipher_walk_next(struct blkcipher_desc *desc,
}
}
bsize = min(walk->walk_blocksize, n);
n = scatterwalk_clamp(&walk->in, n);
n = scatterwalk_clamp(&walk->out, n);