From patchwork Fri Aug 19 20:30:22 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. 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Wong" To: Dave Chinner Subject: [PATCH] xfs: don't perform lookups on zero-height btrees Message-ID: <20160819203022.GD8268@birch.djwong.org> X-ASG-Orig-Subj: [PATCH] xfs: don't perform lookups on zero-height btrees MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Source-IP: aserv0022.oracle.com [141.146.126.234] X-Barracuda-Connect: aserp1040.oracle.com[141.146.126.69] X-Barracuda-Start-Time: 1471638630 X-Barracuda-Encrypted: ECDHE-RSA-AES256-GCM-SHA384 X-Barracuda-URL: https://192.48.176.25:443/cgi-mod/mark.cgi X-Barracuda-Scan-Msg-Size: 739 X-Virus-Scanned: by bsmtpd at sgi.com X-Barracuda-BRTS-Status: 1 X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using per-user scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=2.7 tests=BSF_SC0_MISMATCH_TO, UNPARSEABLE_RELAY X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.32157 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- 0.00 BSF_SC0_MISMATCH_TO Envelope rcpt doesn't match header 0.00 UNPARSEABLE_RELAY Informational: message has unparseable relay lines Cc: linux-xfs@vger.kernel.org, xfs@oss.sgi.com X-BeenThere: xfs@oss.sgi.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com X-Virus-Scanned: ClamAV using ClamSMTP If the caller passes in a cursor to a zero-height btree (which is impossible), we never set block to anything but NULL, which causes the later dereference of it to crash. Instead, just return -EFSCORRUPTED. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/libxfs/xfs_btree.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c index 64fd847..4bffea4 100644 --- a/fs/xfs/libxfs/xfs_btree.c +++ b/fs/xfs/libxfs/xfs_btree.c @@ -1814,6 +1814,10 @@ xfs_btree_lookup( XFS_BTREE_STATS_INC(cur, lookup); + /* No such thing as a zero-level tree. */ + if (cur->bc_nlevels == 0) + return -EFSCORRUPTED; + block = NULL; keyno = 0;