From nobody Fri Sep 19 09:24:50 2025 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 EB534C4321E for ; Fri, 25 Nov 2022 10:22:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230128AbiKYKWP (ORCPT ); Fri, 25 Nov 2022 05:22:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229572AbiKYKWN (ORCPT ); Fri, 25 Nov 2022 05:22:13 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF73C3AC27 for ; Fri, 25 Nov 2022 02:22:08 -0800 (PST) Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NJW5s3fKTzbnhT; Fri, 25 Nov 2022 18:18:09 +0800 (CST) Received: from kwepemm600020.china.huawei.com (7.193.23.147) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 25 Nov 2022 18:22:06 +0800 Received: from localhost.localdomain (10.175.112.125) by kwepemm600020.china.huawei.com (7.193.23.147) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 25 Nov 2022 18:22:05 +0800 From: Peng Zhang To: , CC: , , , , ZhangPeng , Subject: [PATCH] fs/ntfs3: Fix null-ptr-deref on inode->i_op in ntfs_lookup() Date: Fri, 25 Nov 2022 10:21:59 +0000 Message-ID: <20221125102159.91591-1-zhangpeng362@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemm600020.china.huawei.com (7.193.23.147) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: ZhangPeng Syzbot reported a null-ptr-deref bug: ntfs3: loop0: Different NTFS' sector size (1024) and media sector size (512) ntfs3: loop0: Mark volume as dirty due to NTFS errors general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] RIP: 0010:d_flags_for_inode fs/dcache.c:1980 [inline] RIP: 0010:__d_add+0x5ce/0x800 fs/dcache.c:2796 Call Trace: d_splice_alias+0x122/0x3b0 fs/dcache.c:3191 lookup_open fs/namei.c:3391 [inline] open_last_lookups fs/namei.c:3481 [inline] path_openat+0x10e6/0x2df0 fs/namei.c:3688 do_filp_open+0x264/0x4f0 fs/namei.c:3718 do_sys_openat2+0x124/0x4e0 fs/open.c:1310 do_sys_open fs/open.c:1326 [inline] __do_sys_open fs/open.c:1334 [inline] __se_sys_open fs/open.c:1330 [inline] __x64_sys_open+0x221/0x270 fs/open.c:1330 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd If the MFT record of ntfs inode is not a base record, inode->i_op can be NULL. And a null-ptr-deref may happen: ntfs_lookup() dir_search_u() # inode->i_op is set to NULL d_splice_alias() __d_add() d_flags_for_inode() # inode->i_op->get_link null-ptr-deref Fix this by adding a Check on inode->i_op before calling the d_splice_alias() function. Fixes: 4342306f0f0d ("fs/ntfs3: Add file operations and implementation") Reported-by: syzbot+a8f26a403c169b7593fe@syzkaller.appspotmail.com Signed-off-by: ZhangPeng --- fs/ntfs3/namei.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c index bc22cc321a74..7760aedc0672 100644 --- a/fs/ntfs3/namei.c +++ b/fs/ntfs3/namei.c @@ -86,6 +86,16 @@ static struct dentry *ntfs_lookup(struct inode *dir, str= uct dentry *dentry, __putname(uni); } =20 + /* + * Check for a null pointer + * If the MFT record of ntfs inode is not a base record, inode->i_op can = be NULL. + * This causes null pointer dereference in d_splice_alias(). + */ + if (!IS_ERR(inode) && inode->i_op =3D=3D NULL) { + iput(inode); + inode =3D ERR_PTR(-EINVAL); + } + return d_splice_alias(inode, dentry); } =20 --=20 2.25.1