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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F1A7C76196 for ; Mon, 10 Apr 2023 17:37:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230323AbjDJRhi (ORCPT ); Mon, 10 Apr 2023 13:37:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230283AbjDJRhd (ORCPT ); Mon, 10 Apr 2023 13:37:33 -0400 Received: from out30-97.freemail.mail.aliyun.com (out30-97.freemail.mail.aliyun.com [115.124.30.97]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2C7F10DB for ; Mon, 10 Apr 2023 10:37:31 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046056;MF=hsiangkao@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0Vfovcdl_1681148235; Received: from e18g06460.et15sqa.tbsite.net(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0Vfovcdl_1681148235) by smtp.aliyun-inc.com; Tue, 11 Apr 2023 01:37:28 +0800 From: Gao Xiang To: linux-erofs@lists.ozlabs.org Cc: LKML , Gao Xiang , syzbot+aafb3f37cfeb6534c4ac@syzkaller.appspotmail.com Subject: [PATCH] erofs: stop parsing non-compact HEAD index if clusterofs is invalid Date: Tue, 11 Apr 2023 01:37:14 +0800 Message-Id: <20230410173714.104604-1-hsiangkao@linux.alibaba.com> X-Mailer: git-send-email 2.24.4 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Syzbot generated a crafted image [1] with a non-compact HEAD index of clusterofs 33024 while valid numbers should be 0 ~ lclustersize-1, which causes the following unexpected behavior as below: BUG: unable to handle page fault for address: fffff52101a3fff9 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 23ffed067 P4D 23ffed067 PUD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 4398 Comm: kworker/u5:1 Not tainted 6.3.0-rc6-syzkaller-g09a9639e56c0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 Workqueue: erofs_worker z_erofs_decompressqueue_work RIP: 0010:z_erofs_decompress_queue+0xb7e/0x2b40 ... Call Trace: z_erofs_decompressqueue_work+0x99/0xe0 process_one_work+0x8f6/0x1170 worker_thread+0xa63/0x1210 kthread+0x270/0x300 ret_from_fork+0x1f/0x30 Note that normal images or images using compact indexes are not impacted. Let's fix this now. [1] https://lore.kernel.org/r/000000000000ec75b005ee97fbaa@google.com Reported-by: syzbot+aafb3f37cfeb6534c4ac@syzkaller.appspotmail.com Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter") Fixes: 152a333a5895 ("staging: erofs: add compacted compression indexes support") Signed-off-by: Gao Xiang --- fs/erofs/zmap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c index cbd3f72c83e9..7ca108c3834c 100644 --- a/fs/erofs/zmap.c +++ b/fs/erofs/zmap.c @@ -85,6 +85,10 @@ static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m, if (advise & Z_EROFS_LI_PARTIAL_REF) m->partialref = true; m->clusterofs = le16_to_cpu(di->di_clusterofs); + if (m->clusterofs >= 1 << vi->z_logical_clusterbits) { + DBG_BUGON(1); + return -EFSCORRUPTED; + } m->pblk = le32_to_cpu(di->di_u.blkaddr); break; default: -- 2.24.4