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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 E5B9EC2D0A8 for ; Mon, 28 Sep 2020 09:42:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A13E0221E8 for ; Mon, 28 Sep 2020 09:42:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726648AbgI1Jmy (ORCPT ); Mon, 28 Sep 2020 05:42:54 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:34162 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726497AbgI1Jmy (ORCPT ); Mon, 28 Sep 2020 05:42:54 -0400 Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 6A01EC669EBFA0EF986C; Mon, 28 Sep 2020 17:42:52 +0800 (CST) Received: from szvp000203569.huawei.com (10.120.216.130) by DGGEMS408-HUB.china.huawei.com (10.3.19.208) with Microsoft SMTP Server id 14.3.487.0; Mon, 28 Sep 2020 17:42:43 +0800 From: Chao Yu To: CC: , , , Chao Yu Subject: [PATCH] f2fs: fix to do sanity check on segment/section count Date: Mon, 28 Sep 2020 17:42:39 +0800 Message-ID: <20200928094239.66221-1-yuchao0@huawei.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.120.216.130] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As syzbot reported: BUG: KASAN: slab-out-of-bounds in init_min_max_mtime fs/f2fs/segment.c:4710 [inline] BUG: KASAN: slab-out-of-bounds in f2fs_build_segment_manager+0x9302/0xa6d0 fs/f2fs/segment.c:4792 Read of size 8 at addr ffff8880a1b934a8 by task syz-executor682/6878 CPU: 1 PID: 6878 Comm: syz-executor682 Not tainted 5.9.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 init_min_max_mtime fs/f2fs/segment.c:4710 [inline] f2fs_build_segment_manager+0x9302/0xa6d0 fs/f2fs/segment.c:4792 f2fs_fill_super+0x381a/0x6e80 fs/f2fs/super.c:3633 mount_bdev+0x32e/0x3f0 fs/super.c:1417 legacy_get_tree+0x105/0x220 fs/fs_context.c:592 vfs_get_tree+0x89/0x2f0 fs/super.c:1547 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x1387/0x20a0 fs/namespace.c:3192 do_mount fs/namespace.c:3205 [inline] __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount fs/namespace.c:3390 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3390 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The root cause is: if segs_per_sec is larger than one, and segment count in last section is less than segs_per_sec, we will suffer out-of-boundary memory access on sit_i->sentries[] in init_min_max_mtime(). Fix this by adding sanity check among segment count, section count and segs_per_sec value in sanity_check_raw_super(). Signed-off-by: Chao Yu --- fs/f2fs/super.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index a24980aa425d..79d5e0e2225a 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -2834,6 +2834,12 @@ static int sanity_check_raw_super(struct f2fs_sb_info *sbi, return -EFSCORRUPTED; } + if (segment_count_main != total_sections * segs_per_sec) { + f2fs_info(sbi, "Invalid segment/section count (%u != %u * %u)", + segment_count_main, total_sections, segs_per_sec); + return -EFSCORRUPTED; + } + if ((segment_count / segs_per_sec) < total_sections) { f2fs_info(sbi, "Small segment_count (%u < %u * %u)", segment_count, segs_per_sec, total_sections); -- 2.26.2