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 8D289ECAAD5 for ; Wed, 31 Aug 2022 02:45:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231980AbiHaCpR (ORCPT ); Tue, 30 Aug 2022 22:45:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231981AbiHaCpP (ORCPT ); Tue, 30 Aug 2022 22:45:15 -0400 Received: from mail-pg1-x529.google.com (mail-pg1-x529.google.com [IPv6:2607:f8b0:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4703F402D1 for ; Tue, 30 Aug 2022 19:45:12 -0700 (PDT) Received: by mail-pg1-x529.google.com with SMTP id f4so12331137pgc.12 for ; Tue, 30 Aug 2022 19:45:12 -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; bh=CXM0BCPgoVC12DmYCojWwdFvUytvEBCLNePtQadj2oc=; b=RVrp23ebjjGVegEPHJqgy0ff2qLxN53Gg1HWF5r/YiVv77Kgq4GIhwO9kVn2Wm/P0u avkIr1rT9ecWhiSnp0wCBNBj9pvXAeyRloR3sz7I35GpBGLXoxWRbvoQbgsES1wfgW0L hJD3ddwoHspu4Fls+KGySLdVid65hq0HsIPmOsE2NIAnaSOvdxbPO4n9VA70UT4VocfU gW+rmTe6jK5+DhaXHRtclDYpNfuYu6MdL/KjDmH+Tp+FnTgxFm5ipbECtqTTb9KwURKb zO8x3wsUyfA0CyAh84GYnl/5j5WggZZHMHR3ATmuT4MkyXoyPptGhT/E3MbyWloeBH7b 4AZg== 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; bh=CXM0BCPgoVC12DmYCojWwdFvUytvEBCLNePtQadj2oc=; b=seNcKSnABJsowkD3zKT/I9+8GaWWXx/3n9aOlhSGZUlQhS0ida61CIDzo5ZoK4y+Wr FDSCNrZpDk4pnZHO9VCSNuwxPIwoItNAne317Mywu6cz+Htlx0lwPMf4B8juhvlX1Qjb tzp7C/wdcK6JSLMV9e1X01UNqk2mhL29BqH2WmQlbz+CYmvN5+rtyuYSQCLGhtEhzmI/ 3DgzPsQflDOAKuO1zVXECWn2/VE65UEqlXakhMuMUIJ6ByiGF3uOs2KBhdXdsk9btvAV uSnmytG2zo34SXMOPT/QbUCyf1q31HeYbMn/Q8Gx0EPymKgHA7g8p0Mmb1VBpA+7ZCgm kmZw== X-Gm-Message-State: ACgBeo2t19ncNHwOHloplDY/OSYHhAViO4jN6/DHO7wT3D/PTX/rRcQ6 +bFfc5JzDJIw50Ia70m0pCU= X-Google-Smtp-Source: AA6agR6x/Yx9xBLRaRcgkEuApEi/oYC26IR8aGl/VlV9rHwPX9GFwlqYUbc+Eywr/HgKCZGRAEdjMw== X-Received: by 2002:a05:6a00:1827:b0:538:3d5f:fd3 with SMTP id y39-20020a056a00182700b005383d5f0fd3mr12463402pfa.28.1661913912405; Tue, 30 Aug 2022 19:45:12 -0700 (PDT) Received: from localhost ([36.112.86.8]) by smtp.gmail.com with ESMTPSA id b5-20020a1709027e0500b0016c1b178628sm10310035plm.269.2022.08.30.19.45.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Aug 2022 19:45:12 -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 2/3] ntfs: fix out-of-bounds read in ntfs_attr_find() Date: Wed, 31 Aug 2022 10:43:36 +0800 Message-Id: <8a43c95b068e4ca404e864d64a2a44d357754e5c.1661875711.git.yin31149@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: ================================================================== BUG: KASAN: use-after-free in ntfs_attr_find+0xc02/0xce0 fs/ntfs/attrib.c:597 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=0|zone=1|lastcpupid=0x7ff) 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 ================================================================== 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.com Signed-off-by: chenxiaosong (A) Link: https://lore.kernel.org/all/1636796c-c85e-7f47-e96f-e074fee3c7d3@huawei.com/ Signed-off-by: Dan Carpenter Link: https://groups.google.com/g/syzkaller-bugs/c/t_XdeKPGTR4/m/LECAuIGcBgAJ Signed-off-by: Hawkins Jiawei --- 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..904734e34507 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 = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) { u8 *mrec_end = (u8 *)ctx->mrec + le32_to_cpu(ctx->mrec->bytes_allocated); - u8 *name_end = (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, *arec_head_end; + + /* check for wrap around */ + if ((u8 *)a < (u8 *)ctx->mrec) + break; + + /* check whether Attribute Record Header is within bounds */ + arec_head_end = (u8 *)a + sizeof(ATTR_RECORD); + if (arec_head_end < (u8 *)a || arec_head_end > mrec_end) break; + + /* check whether ATTR_RECORD's name is within bounds */ + name_end = (u8 *)a + le16_to_cpu(a->name_offset) + + a->name_length * sizeof(ntfschar); + if (name_end > mrec_end) + break; + ctx->attr = a; if (unlikely(le32_to_cpu(a->type) > le32_to_cpu(type) || a->type == AT_END)) -- 2.25.1