From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753835AbcI1JaK (ORCPT ); Wed, 28 Sep 2016 05:30:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57431 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752487AbcI1JIc (ORCPT ); Wed, 28 Sep 2016 05:08:32 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, xiakaixu , Ard Biesheuvel , Herbert Xu Subject: [PATCH 4.7 04/69] crypto: skcipher - Fix blkcipher walk OOM crash Date: Wed, 28 Sep 2016 11:04:46 +0200 Message-Id: <20160928090445.232830170@linuxfoundation.org> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20160928090445.054716307@linuxfoundation.org> References: <20160928090445.054716307@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Herbert Xu 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 Reported-by: Ard Biesheuvel Signed-off-by: Herbert Xu Tested-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman --- crypto/blkcipher.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/crypto/blkcipher.c +++ b/crypto/blkcipher.c @@ -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);