Patch "crypto: skcipher - Fix blkcipher walk OOM crash" has been added to the 4.4-stable tree

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

crypto: skcipher - Fix blkcipher walk OOM crash

to the 4.4-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-skcipher-fix-blkcipher-walk-oom-crash.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Herbert Xu <[email protected]>
Date: Tue, 13 Sep 2016 14:43:29 +0800
Subject: crypto: skcipher - Fix blkcipher walk OOM crash

From: Herbert Xu <[email protected]>

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.

---
 crypto/blkcipher.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -234,6 +234,8 @@ static int blkcipher_walk_next(struct bl
 		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 bl
 		}
 	}
 
-	bsize = min(walk->walk_blocksize, n);
 	n = scatterwalk_clamp(&walk->in, n);
 	n = scatterwalk_clamp(&walk->out, n);
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/crypto-echainiv-replace-chaining-with-multiplication.patch queue-4.4/crypto-arm64-aes-ctr-fix-null-dereference-in-tail-processing.patch queue-4.4/crypto-arm-aes-ctr-fix-null-dereference-in-tail-processing.patch queue-4.4/crypto-skcipher-fix-blkcipher-walk-oom-crash.patch