From nobody Tue Apr 7 03:51:43 2026 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 18407ECAAD3 for ; Wed, 31 Aug 2022 16:12:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230474AbiHaQMc (ORCPT ); Wed, 31 Aug 2022 12:12:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231356AbiHaQM1 (ORCPT ); Wed, 31 Aug 2022 12:12:27 -0400 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63BC3D11F1 for ; Wed, 31 Aug 2022 09:12:21 -0700 (PDT) Received: by mail-pf1-x429.google.com with SMTP id q15so9513978pfn.11 for ; Wed, 31 Aug 2022 09:12:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date; bh=f8MgvGh+ksHn1mHkWpjvZ43exvRjNzmYkYNUVIU3dnI=; b=N9vsfmbi93IeCMV0maJHVIvMTC6H2nPgQxnlPoOFJFEQzYYzYI3FxpE9EKxTENxN76 HlxRpRUP0AlmAskrDYhxf9LUQ+I+eFP/e5H+lB6j01dDuB0FubyTBGhLoMrrub7ZPXer uYyc/gmNhT7dZQiyUTV59Fc2p6/i59TEQrVLfeTnC1WlIckL3GOIsGOvZD91mLeZjIrE 8Gy2V5wsSUBmoJdZfftBrHRu+snegVnG4Hc2v2DkEOZPqfEpb1nnaD1amm3of49arl+U Mq9mSbSq5VQhT8uDrUjkwj19rYYW9qdkg6Xx4o6t5pX3XD3JoCv1zvrxMlL/MWIb9ET+ ohEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date; bh=f8MgvGh+ksHn1mHkWpjvZ43exvRjNzmYkYNUVIU3dnI=; b=Qdn+ZvFOXvugQf9X0NgFPUD3U2GzWQ0ujso9pk/yfnE/s8t8+fXOSl4X1s/CrJNELn qEN2SXFs8VK5BYqO8mCNzPSrQ6TSG4+bBdvtNH9DmjH+narGwjaIsxRqpRukN2J/3GwT z+VgUF6jWcbujJzzj6mYrNlBJMlWdB1XLJRcv48k2Kvuk3t2WvzY/XHrz0JOmaY5AzfH OGWwdWosDd0FbNTc9tkQZX+gDRgpBYKrNQHmlh2wmac+/nRPRecrq2G4tBETOBpfV0mE GzVFSvwvOFrBRmphDUM1uZu4fyazf1+xgSEEkff99QiGwVtjl/k8VXb3ens3ZgLJ2uOn SVlA== X-Gm-Message-State: ACgBeo1/KDHbHbwlnF49Gsf4f9K2vYMZmLOoLnlqpX+CajiA81KmoQKu I25XDeveNgT9VtGijuc1Kzc= X-Google-Smtp-Source: AA6agR5sUHH4T3dAKze9jkp5hKoKpRegW3m0w6N5czp+D02Q+Qy6zxLre8UGpdUtsxYF5C5OthN1DQ== X-Received: by 2002:a63:256:0:b0:42f:b14b:2085 with SMTP id 83-20020a630256000000b0042fb14b2085mr6104065pgc.189.1661962341421; Wed, 31 Aug 2022 09:12:21 -0700 (PDT) Received: from localhost ([36.112.195.70]) by smtp.gmail.com with ESMTPSA id x11-20020a17090ab00b00b001fbc0e9edafsm1470409pjq.56.2022.08.31.09.12.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 Aug 2022 09:12:21 -0700 (PDT) From: Hawkins Jiawei To: syzbot+5f8dcabe4a3b2c51c607@syzkaller.appspotmail.com, Anton Altaparmakov Cc: akpm@linux-foundation.org, chenxiaosong2@huawei.com, linux-kernel@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net, syzkaller-bugs@googlegroups.com, yin31149@gmail.com, 18801353760@163.com, Dan Carpenter Subject: [PATCH v2 2/3] ntfs: fix out-of-bounds read in ntfs_attr_find() Date: Thu, 1 Sep 2022 00:09:36 +0800 Message-Id: <20220831160935.3409-3-yin31149@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220831160935.3409-1-yin31149@gmail.com> References: <20220831160935.3409-1-yin31149@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Kernel will iterates over ATTR_RECORDs in mft record in ntfs_attr_find(). To ensure access on these ATTR_RECORDs are within bounds, kernel will do some checking during iteration. The problem is that during checking whether ATTR_RECORD's name is within bounds, kernel will dereferences the ATTR_RECORD name_offset field, before checking this ATTR_RECORD strcture is within bounds. This problem may result out-of-bounds read in ntfs_attr_find(), reported by Syzkaller: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D BUG: KASAN: use-after-free in ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:5= 97 Read of size 2 at addr ffff88807e352009 by task syz-executor153/3607 [...] Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597 ntfs_attr_lookup+0x1056/0x2070 fs/ntfs/attrib.c:1193 ntfs_read_inode_mount+0x89a/0x2580 fs/ntfs/inode.c:1845 ntfs_fill_super+0x1799/0x9320 fs/ntfs/super.c:2854 mount_bdev+0x34d/0x410 fs/super.c:1400 legacy_get_tree+0x105/0x220 fs/fs_context.c:610 vfs_get_tree+0x89/0x2f0 fs/super.c:1530 do_new_mount fs/namespace.c:3040 [inline] path_mount+0x1326/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] The buggy address belongs to the physical page: page:ffffea0001f8d400 refcount:1 mapcount:0 mapping:0000000000000000 index:= 0x0 pfn:0x7e350 head:ffffea0001f8d400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=3D0|zone=3D1|lastcpupid=3D0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011842140 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807e351f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807e351f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807e352000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807e352080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807e352100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D This patch solves it by moving the ATTR_RECORD strcture's bounds checking earlier, then checking whether ATTR_RECORD's name is within bounds. What's more, this patch also add some comments to improve its maintainability. Reported-and-tested-by: syzbot+5f8dcabe4a3b2c51c607@syzkaller.appspotmail.c= om Signed-off-by: chenxiaosong (A) Link: https://lore.kernel.org/all/1636796c-c85e-7f47-e96f-e074fee3c7d3@huaw= ei.com/ Signed-off-by: Dan Carpenter Link: https://groups.google.com/g/syzkaller-bugs/c/t_XdeKPGTR4/m/LECAuIGcBg= AJ Signed-off-by: Hawkins Jiawei --- v1->v2: * Refactor check on Attribute Record Header suggested by Dan Carpenter. fs/ntfs/attrib.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c index 52615e6090e1..cec4be2a2d23 100644 --- a/fs/ntfs/attrib.c +++ b/fs/ntfs/attrib.c @@ -594,11 +594,23 @@ static int ntfs_attr_find(const ATTR_TYPE type, const= ntfschar *name, for (;; a =3D (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) { u8 *mrec_end =3D (u8 *)ctx->mrec + le32_to_cpu(ctx->mrec->bytes_allocated); - u8 *name_end =3D (u8 *)a + le16_to_cpu(a->name_offset) + - a->name_length * sizeof(ntfschar); - if ((u8*)a < (u8*)ctx->mrec || (u8*)a > mrec_end || - name_end > mrec_end) + u8 *name_end; + + /* check whether ATTR_RECORD wrap */ + if ((u8 *)a < (u8 *)ctx->mrec) + break; + + /* check whether Attribute Record Header is within bounds */ + if ((u8 *)a > mrec_end || + (u8 *)a + sizeof(ATTR_RECORD) > mrec_end) break; + + /* check whether ATTR_RECORD's name is within bounds */ + name_end =3D (u8 *)a + le16_to_cpu(a->name_offset) + + a->name_length * sizeof(ntfschar); + if (name_end > mrec_end) + break; + ctx->attr =3D a; if (unlikely(le32_to_cpu(a->type) > le32_to_cpu(type) || a->type =3D=3D AT_END)) --=20 2.25.1