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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, 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 7069FC433FF for ; Mon, 29 Jul 2019 04:20:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 379DB2073F for ; Mon, 29 Jul 2019 04:20:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="VzTddNoF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726518AbfG2EUx (ORCPT ); Mon, 29 Jul 2019 00:20:53 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:53078 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726164AbfG2EUw (ORCPT ); Mon, 29 Jul 2019 00:20:52 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6T4JQ2t135574; Mon, 29 Jul 2019 04:20:35 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=KJOwyKfBt2HnHY+cw2gWHTBRREdfic7k/AhbXGx7f3g=; b=VzTddNoFOlQpv3f6xBFCY1P8iJGShnkogLd7tc2Kbo60tNv3szbv7GQRFD2RNLznRcpN KQ5M9CHRfmOBYqH2v5IVo3faYRJUaF2ZhFXBfKS+t9e1APU0UIKZyzaVNk0DFllddlTn LpbeCAh7F2oBXxNy7YVSj5e2Hqp6Sn3B2mw9bH06C/I0zWEujiIvYRt3jFo3HXRscjjz 8d5n0rt9CUL1wZAal/y4ehlrTvZzb8xVtY/3eo8Kz/ocbLCB1l3LXuyp4cRFhfO++VoW qPHsuipHcnjPsDLxQ5jgCHcqf+FMFx+yEIItMXkn3EOUFaN4LJS4NQ5YkpeSX5dVeNzv rA== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 2u0f8qmpw9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 29 Jul 2019 04:20:35 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6T4HnoI087007; Mon, 29 Jul 2019 04:20:34 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 2u0bqt8xe6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 29 Jul 2019 04:20:34 +0000 Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x6T4KXcq030951; Mon, 29 Jul 2019 04:20:33 GMT Received: from localhost (/10.159.132.165) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 28 Jul 2019 21:20:32 -0700 Date: Sun, 28 Jul 2019 21:20:34 -0700 From: "Darrick J. Wong" To: Jia-Ju Bai Cc: bfoster@redhat.com, sandeen@sandeen.net, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fs: xfs: Fix possible null-pointer dereferences in xchk_da_btree_block_check_sibling() Message-ID: <20190729042034.GM1561054@magnolia> References: <20190729032401.28081-1-baijiaju1990@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190729032401.28081-1-baijiaju1990@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9332 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1907290052 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9332 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1907290052 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 29, 2019 at 11:24:01AM +0800, Jia-Ju Bai wrote: > In xchk_da_btree_block_check_sibling(), there is an if statement on > line 274 to check whether ds->state->altpath.blk[level].bp is NULL: > if (ds->state->altpath.blk[level].bp) > > When ds->state->altpath.blk[level].bp is NULL, it is used on line 281: > xfs_trans_brelse(..., ds->state->altpath.blk[level].bp); > struct xfs_buf_log_item *bip = bp->b_log_item; > ASSERT(bp->b_transp == tp); > > Thus, possible null-pointer dereferences may occur. > > To fix these bugs, ds->state->altpath.blk[level].bp is checked before > being used. > > These bugs are found by a static analysis tool STCheck written by us. > > Signed-off-by: Jia-Ju Bai > --- > fs/xfs/scrub/dabtree.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/scrub/dabtree.c b/fs/xfs/scrub/dabtree.c > index 94c4f1de1922..33ff90c0dd70 100644 > --- a/fs/xfs/scrub/dabtree.c > +++ b/fs/xfs/scrub/dabtree.c > @@ -278,7 +278,9 @@ xchk_da_btree_block_check_sibling( > /* Compare upper level pointer to sibling pointer. */ > if (ds->state->altpath.blk[level].blkno != sibling) > xchk_da_set_corrupt(ds, level); > - xfs_trans_brelse(ds->dargs.trans, ds->state->altpath.blk[level].bp); > + if (ds->state->altpath.blk[level].bp) > + xfs_trans_brelse(ds->dargs.trans, > + ds->state->altpath.blk[level].bp); Indentation here (in xfs we use two spaces) Also, uh, shouldn't we set ds->state->altpath.blk[level].bp to NULL since we've released the buffer? --D > out: > return error; > } > -- > 2.17.0 >