From patchwork Mon Jan 28 11:47:28 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yao Liu X-Patchwork-Id: 1031875 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=ucloud.cn Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43p7Pf4qWhz9s3q for ; Mon, 28 Jan 2019 22:56:06 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726668AbfA1L4F (ORCPT ); Mon, 28 Jan 2019 06:56:05 -0500 Received: from m97188.mail.qiye.163.com ([220.181.97.188]:9177 "EHLO m97188.mail.qiye.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726611AbfA1L4F (ORCPT ); Mon, 28 Jan 2019 06:56:05 -0500 X-Greylist: delayed 511 seconds by postgrey-1.27 at vger.kernel.org; Mon, 28 Jan 2019 06:56:04 EST Received: from kernel_test2.localdomain (unknown [120.132.1.243]) by m97188.mail.qiye.163.com (Hmail) with ESMTPA id B4BFD96BC38; Mon, 28 Jan 2019 19:47:30 +0800 (CST) From: Yao Liu To: sfrench@samba.org Cc: linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, Yao Liu Subject: [PATCH] cifs: Fix NULL pointer dereference of devname Date: Mon, 28 Jan 2019 19:47:28 +0800 Message-Id: <1548676048-19626-1-git-send-email-yotta.liu@ucloud.cn> X-Mailer: git-send-email 1.8.3.1 X-HM-Spam-Status: e1kIGBQJHllBS1VLV1koWUFJQjdXWS1ZQUlXWQkOFx4IWUFZMjUtOjcyP0 FLVUtZBg++ X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6ORw6HRw6LjlPFRcuOC0QTC8d QyMwCTdVSlVKTk9DTUxNS05LQkxMVTMWGhIXVQIUDw8aVRcSDjsOGBcUDh9VGBVFWVdZEgtZQVlK SUtVSkhJVUpVSU9IWVdZCAFZQUlKQkk3Bg++ X-HM-Tid: 0a6894492fce20bckuqyb4bfd96bc38 Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org There is a NULL pointer dereference of devname in strspn() The oops looks something like: CIFS: Attempting to mount (null) BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 ... RIP: 0010:strspn+0x0/0x50 ... Call Trace: ? cifs_parse_mount_options+0x222/0x1710 [cifs] ? cifs_get_volume_info+0x2f/0x80 [cifs] cifs_setup_volume_info+0x20/0x190 [cifs] cifs_get_volume_info+0x50/0x80 [cifs] cifs_smb3_do_mount+0x59/0x630 [cifs] ? ida_alloc_range+0x34b/0x3d0 cifs_do_mount+0x11/0x20 [cifs] mount_fs+0x52/0x170 vfs_kern_mount+0x6b/0x170 do_mount+0x216/0xdc0 ksys_mount+0x83/0xd0 __x64_sys_mount+0x25/0x30 do_syscall_64+0x65/0x220 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fix this by adding a NULL check on devname in cifs_parse_devname() Signed-off-by: Yao Liu --- fs/cifs/connect.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 683310f..39abb18 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -1465,6 +1465,11 @@ static int cifs_parse_security_flavors(char *value, const char *delims = "/\\"; size_t len; + if (unlikely(!devname || !*devname)) { + cifs_dbg(VFS, "Device name not specified.\n"); + return -EINVAL; + } + /* make sure we have a valid UNC double delimiter prefix */ len = strspn(devname, delims); if (len != 2)