tree b47e600b95fedd3039ccf9edc9aa05a093d3e83e
parent a85b32ebaac08970d41a7b0105ce51fed90d153e
author Wenwen Wang <wang6495@umn.edu> 1525740403 -0500
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1533275723 +0200

scsi: 3w-9xxx: fix a missing-check bug

[ Upstream commit c9318a3e0218bc9dacc25be46b9eec363259536f ]

In twa_chrdev_ioctl(), the ioctl driver command is firstly copied from
the userspace pointer 'argp' and saved to the kernel object
'driver_command'.  Then a security check is performed on the data buffer
size indicated by 'driver_command', which is
'driver_command.buffer_length'. 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 size between the two copies. This way, the user can bypass
the security check and inject invalid data buffer size. This can cause
potential security issues in the following execution.

This patch checks for capable(CAP_SYS_ADMIN) in twa_chrdev_open()t o
avoid the above issues.

Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Acked-by: Adam Radford <aradford@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>