From: Herbert Xu Date: Tue, 13 Sep 2016 06:43:29 +0000 (+0800) Subject: crypto: skcipher - Fix blkcipher walk OOM crash X-Git-Tag: v4.8-rc8~18^2~4 X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=acdb04d0b36769b3e05990c488dc74d8b7ac8060 crypto: skcipher - Fix blkcipher walk OOM crash 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") Cc: stable@vger.kernel.org Reported-by: xiakaixu Reported-by: Ard Biesheuvel Signed-off-by: Herbert Xu Tested-by: Ard Biesheuvel --- diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c index 369999530108..a832426820e8 100644 --- a/crypto/blkcipher.c +++ b/crypto/blkcipher.c @@ -233,6 +233,8 @@ 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) || @@ -245,7 +247,6 @@ 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);