Arch Linux: 201710-25 High: linux-hardened Privilege Escalation Issue

Arch Linux Security Advisory ASA-201710-25
=========================================
Severity: High
Date    : 2017-10-16
CVE-ID  : CVE-2017-5123
Package : linux-hardened
Type    : privilege escalation
Remote  : No
Link    : https://security.archlinux.org/AVG-446

Summary
======
The package linux-hardened before version 4.13.7.a-1 is vulnerable to
privilege escalation.

Resolution
=========
Upgrade to 4.13.7.a-1.

# pacman -Syu "linux-hardened>=4.13.7.a-1"

The problem has been fixed upstream in version 4.13.7.a.

Workaround
=========
None.

Description
==========
It was discovered that when the waitid() syscall in Linux kernel v4.13
was refactored, it accidentally stopped checking that the incoming
argument was pointing to userspace. This allowed local attackers to
write directly to kernel memory, which could lead to privilege
escalation.

Impact
=====
A local attacker is able to escalate privileges on the affected host.

References
=========
https://www.openwall.com/lists/oss-security/2017/10/12/18
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=96ca579a1ecc943b75beba58bebb0356f6cc4b51
https://security.archlinux.org/CVE-2017-5123