From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7D7DC35247 for ; Tue, 4 Feb 2020 21:39:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 849272084E for ; Tue, 4 Feb 2020 21:39:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727566AbgBDVjg (ORCPT ); Tue, 4 Feb 2020 16:39:36 -0500 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:56622 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727563AbgBDVjg (ORCPT ); Tue, 4 Feb 2020 16:39:36 -0500 Received: from dread.disaster.area (pa49-181-161-120.pa.nsw.optusnet.com.au [49.181.161.120]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id BED323A2E10; Wed, 5 Feb 2020 08:39:33 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1iz5uu-0005t7-8t; Wed, 05 Feb 2020 08:39:32 +1100 Date: Wed, 5 Feb 2020 08:39:32 +1100 From: Dave Chinner To: Zorro Lang Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH] xfs: fix invalid pointer dereference in xfs_attr3_node_inactive Message-ID: <20200204213932.GM20628@dread.disaster.area> References: <20200204070636.25572-1-zlang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200204070636.25572-1-zlang@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=W5xGqiek c=1 sm=1 tr=0 a=SkgQWeG3jiSQFIjTo4+liA==:117 a=SkgQWeG3jiSQFIjTo4+liA==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=l697ptgUJYAA:10 a=7-415B0cAAAA:8 a=9zip6S78dTbaoqQT7ZoA:9 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Tue, Feb 04, 2020 at 03:06:36PM +0800, Zorro Lang wrote: > This patch fixes below KASAN report. The xfs_attr3_node_inactive() > gets 'child_bp' at there: > error = xfs_trans_get_buf(*trans, mp->m_ddev_targp, > child_blkno, > XFS_FSB_TO_BB(mp, mp->m_attr_geo->fsbcount), 0, > &child_bp); > if (error) > return error; > error = bp->b_error; > > But it turns to use 'bp', not 'child_bp'. And the 'bp' has been freed by: > xfs_trans_brelse(*trans, bp); .... > --- > fs/xfs/xfs_attr_inactive.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c > index bbfa6ba84dcd..26230d150bf2 100644 > --- a/fs/xfs/xfs_attr_inactive.c > +++ b/fs/xfs/xfs_attr_inactive.c > @@ -211,7 +211,7 @@ xfs_attr3_node_inactive( > &child_bp); > if (error) > return error; > - error = bp->b_error; > + error = child_bp->b_error; > if (error) { > xfs_trans_brelse(*trans, child_bp); > return error; Isn't this dead code now? i.e. any error that occurs on the buffer during a xfs_trans_get_buf() call is returned directly and so it's caught by the "if (error)" check. Hence this whole child_bp->b_error check can be removed, right? Cheers, Dave. -- Dave Chinner david@fromorbit.com