From patchwork Sun Nov 24 04:43:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lizhi Xu X-Patchwork-Id: 13883991 Received: from mx0b-0064b401.pphosted.com (mx0b-0064b401.pphosted.com [205.220.178.238]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B34DE817; Sun, 24 Nov 2024 04:43:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.178.238 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732423429; cv=none; b=eOEYKkxLYphoKHeACLrjw9MF3mPR8uRuGaR5vbEUw8gi8vmXxsnw+tIKi4yDNpHgUlre91NMWcvp0kz3Ou44dmm6jW3hMWMrHkb/jTuJPCpjiA+NLmzdmD1OMCZ5Hcfi0fTEiOPCyR06Zl5rFWlYvaMZP7Lz7Qe3XeRIMfeIRug= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732423429; c=relaxed/simple; bh=0118LA88yubD1HbW8rhHx8ypMvILVmBnQzFIaafSCsU=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=f4Ai3Vk++kRc0qJ+H3A9QdyUWOpemzkEEwB9HAVLrbQTO+HcaEGNg25Md61/YSppOADBdUREcdCCFbw+qBJaBZxvc9mtbTtLKkyUsNPlVLxFls8odi+Zilk7upQRJ6bvr2TqJUc5PoCl81wQJQNMP2JYQbF9hxTQcoyTPIuEcXU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com; spf=pass smtp.mailfrom=windriver.com; arc=none smtp.client-ip=205.220.178.238 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=windriver.com Received: from pps.filterd (m0250812.ppops.net [127.0.0.1]) by mx0a-0064b401.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4AO4h7bE002856; Sun, 24 Nov 2024 04:43:07 GMT Received: from ala-exchng01.corp.ad.wrs.com (ala-exchng01.wrs.com [147.11.82.252]) by mx0a-0064b401.pphosted.com (PPS) with ESMTPS id 4336188tja-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Sun, 24 Nov 2024 04:43:06 +0000 (GMT) Received: from ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) by ala-exchng01.corp.ad.wrs.com (147.11.82.252) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.43; Sat, 23 Nov 2024 20:43:05 -0800 Received: from pek-lpd-ccm6.wrs.com (147.11.136.210) by ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) with Microsoft SMTP Server id 15.1.2507.43 via Frontend Transport; Sat, 23 Nov 2024 20:43:03 -0800 From: Lizhi Xu To: CC: , , , , , , , , Subject: [PATCH V6] fs/ntfs3: check if the inode is bad before instantiating dentry Date: Sun, 24 Nov 2024 12:43:02 +0800 Message-ID: <20241124044302.3728104-1-lizhi.xu@windriver.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241123013252.GQ3387508@ZenIV> References: <20241123013252.GQ3387508@ZenIV> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-ORIG-GUID: oJ2W6tyR1st-h82seTu-bS8JrptP_YYF X-Proofpoint-GUID: oJ2W6tyR1st-h82seTu-bS8JrptP_YYF X-Authority-Analysis: v=2.4 cv=O65rvw9W c=1 sm=1 tr=0 ts=6742aeda cx=c_pps a=/ZJR302f846pc/tyiSlYyQ==:117 a=/ZJR302f846pc/tyiSlYyQ==:17 a=VlfZXiiP6vEA:10 a=edf1wS77AAAA:8 a=hSkVLCK3AAAA:8 a=t7CeM3EgAAAA:8 a=m1U9UHP-Xm7QjdHxdRgA:9 a=DcSpbTIhAlouE1Uv7lRv:22 a=cQPPKAXgyycSBL8etih5:22 a=FdTzh2GWekK77mhwV6Dw:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-11-24_03,2024-11-21_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 suspectscore=0 clxscore=1015 mlxscore=0 bulkscore=0 mlxlogscore=773 spamscore=0 priorityscore=1501 lowpriorityscore=0 adultscore=0 malwarescore=0 impostorscore=0 classifier=spam authscore=0 adjust=0 reason=mlx scancount=1 engine=8.21.0-2409260000 definitions=main-2411240037 syzbot reported a null-ptr-deref in pick_link. [1] First, i_link and i_dir_seq are in the same union, they share the same memory address, and i_dir_seq will be updated during the execution of walk_component, which makes the value of i_link equal to i_dir_seq. Secondly, the chmod execution failed, which resulted in setting the mode value of file0's inode to REG when executing ntfs_bad_inode. Third, during the execution of the link syscall, two things are done in d_instantiate. One is to set the bad inode to the dentry of the bus. More importantly, the symlink flag obtained in d_flags_for_inode(bad inode) is used to update the d_flags of the dentry of the bus through __d_set_inode_and_type, which will cause the dentry flag of the created bus to have symlink. The bus should have been a hardlink, but it eventually became a symlink. These two points constitute the root cause. When executing the mount syscall, in walk_component(), when executing to step_into() and using d_is_symlink() to judge, because the flag of the dentry of the bus is symlink, it leads to the wrong process, and trigger null-ptr-deref in pick_link(). Note: ("file0, bus" are defined in reproducer [2]) To avoid null-ptr-deref in pick_link, when creating a hardlink, first check whether the inode of file is already bad. [1] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 5310 Comm: syz-executor255 Not tainted 6.12.0-rc6-syzkaller-00318-ga9cda7c0ffed #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:pick_link+0x51c/0xd50 fs/namei.c:1864 Code: c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 fc 00 e9 ff 48 8b 2b 48 85 ed 0f 84 92 00 00 00 e8 7b 36 7f ff 48 89 e8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 a2 05 00 00 0f b6 5d 00 bf 2f 00 00 00 RSP: 0018:ffffc9000d147998 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88804558dec8 RCX: ffff88801ec7a440 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffffff8215a35f R09: 1ffffffff203a13d R10: dffffc0000000000 R11: fffffbfff203a13e R12: 1ffff92001a28f93 R13: ffffc9000d147af8 R14: 1ffff92001a28f5f R15: dffffc0000000000 FS: 0000555577611380(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcc0a595ed8 CR3: 0000000035760000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: step_into+0xca9/0x1080 fs/namei.c:1923 lookup_last fs/namei.c:2556 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2580 filename_lookup+0x256/0x610 fs/namei.c:2609 user_path_at+0x3a/0x60 fs/namei.c:3016 do_mount fs/namespace.c:3844 [inline] __do_sys_mount fs/namespace.c:4057 [inline] __se_sys_mount+0x297/0x3c0 fs/namespace.c:4034 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4b18ad5b19 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc2e486c48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007f4b18ad5b19 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000000 RBP: 00007f4b18b685f0 R08: 0000000000000000 R09: 00005555776124c0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc2e486c70 R13: 00007ffc2e486e98 R14: 431bde82d7b634db R15: 00007f4b18b1e03b [2] move_mount(0xffffffffffffff9c, &(0x7f00000003c0)='./file0\x00', 0xffffffffffffff9c, &(0x7f0000000400)='./file0/file0\x00', 0x140) chmod(&(0x7f0000000080)='./file0\x00', 0x0) link(&(0x7f0000000200)='./file0\x00', &(0x7f0000000240)='./bus\x00') mount$overlay(0x0, &(0x7f00000000c0)='./bus\x00', 0x0, 0x0, 0x0) Reported-by: syzbot+73d8fc29ec7cba8286fa@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=73d8fc29ec7cba8286fa Signed-off-by: Lizhi Xu --- V1 --> V2: add the root cause of the i_link not set issue and imporve the check V2 --> V3: when creating a symbolic link, first check whether the inode of file is bad. V3 --> V4: add comments for symlink use bad inode, it is the root cause V4 --> V5: update comments for link command, it is creating hardlink V5 --> V6: add comments for link syscall return a symlink and update subject fs/ntfs3/inode.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c index be04d2845bb7..fefbdcf75016 100644 --- a/fs/ntfs3/inode.c +++ b/fs/ntfs3/inode.c @@ -1719,6 +1719,9 @@ int ntfs_link_inode(struct inode *inode, struct dentry *dentry) struct ntfs_sb_info *sbi = inode->i_sb->s_fs_info; struct NTFS_DE *de; + if (is_bad_inode(inode)) + return -EIO; + /* Allocate PATH_MAX bytes. */ de = __getname(); if (!de)