linux-kernel - [PATCH 4.17 215/336] scsi: 3w-xxxx: fix a missing-check bug

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180801165037.300656773@linuxfoundation.org>
Date:   Wed,  1 Aug 2018 18:49:10 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Wenwen Wang <wang6495@....edu>,
        Adam Radford <aradford@...il.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.17 215/336] scsi: 3w-xxxx: fix a missing-check bug

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Wenwen Wang <wang6495@....edu>

[ Upstream commit 9899e4d3523faaef17c67141aa80ff2088f17871 ]

In tw_chrdev_ioctl(), the length of the data buffer is firstly copied
from the userspace pointer 'argp' and saved to the kernel object
'data_buffer_length'. Then a security check is performed on it to make
sure that the length is not more than 'TW_MAX_IOCTL_SECTORS *
512'. Otherwise, an error code -EINVAL is returned. If the security
check is passed, the entire ioctl command is copied again from the
'argp' pointer and saved to the kernel object 'tw_ioctl'. Then, various
operations are performed on 'tw_ioctl' according to the 'cmd'. Given
that the 'argp' pointer resides in userspace, a malicious userspace
process can race to change the buffer length between the two
copies. This way, the user can bypass the security check and inject
invalid data buffer length. This can cause potential security issues in
the following execution.

This patch checks for capable(CAP_SYS_ADMIN) in tw_chrdev_open() to
avoid the above issues.

Signed-off-by: Wenwen Wang <wang6495@....edu>
Acked-by: Adam Radford <aradford@...il.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/scsi/3w-xxxx.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/scsi/3w-xxxx.c
+++ b/drivers/scsi/3w-xxxx.c
@@ -1033,6 +1033,9 @@ static int tw_chrdev_open(struct inode *

 	dprintk(KERN_WARNING "3w-xxxx: tw_ioctl_open()\n");

+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
 	minor_number = iminor(inode);
 	if (minor_number >= tw_device_extension_count)
 		return -ENODEV;