Ubuntu Security Notices
USN-3256-2

USN-3256-2: Linux kernel (HWE) vulnerability

Publication date

5 April 2017

Overview

The system could be made to crash under certain conditions.

Releases

16.04 LTS 14.04 LTS 12.04

Packages

linux-hwe - Linux hardware enablement (HWE) kernel
linux-lts-trusty - Linux hardware enablement kernel from Trusty for Precise
linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty

Details

USN-3256-1 fixed vulnerabilities in the Linux kernel for Ubuntu
14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 16.10. This update provides
the corresponding updates for the Linux Hardware Enablement (HWE)
kernel for each of the respective prior Ubuntu LTS releases.

Andrey Konovalov discovered that the AF_PACKET implementation in the Linux
kernel did not properly validate certain block-size data. A local attacker
could use this to cause a denial of service (system crash).

Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release	Package Version
16.04 xenial	linux-image-4.8.0-46-generic – 4.8.0-46.49~16.04.1
	linux-image-4.8.0-46-generic-lpae – 4.8.0-46.49~16.04.1
	linux-image-4.8.0-46-lowlatency – 4.8.0-46.49~16.04.1
14.04 trusty	linux-image-4.4.0-72-generic – 4.4.0-72.93~14.04.1
	linux-image-4.4.0-72-generic-lpae – 4.4.0-72.93~14.04.1
	linux-image-4.4.0-72-lowlatency – 4.4.0-72.93~14.04.1
	linux-image-4.4.0-72-powerpc-e500mc – 4.4.0-72.93~14.04.1
	linux-image-4.4.0-72-powerpc-smp – 4.4.0-72.93~14.04.1
	linux-image-4.4.0-72-powerpc64-smp – 4.4.0-72.93~14.04.1
12.04 precise	linux-image-3.13.0-116-generic – 3.13.0-116.163~precise1
	linux-image-3.13.0-116-generic-lpae – 3.13.0-116.163~precise1
	linux-image-generic-lpae-lts-trusty – 3.13.0.116.107
	linux-image-generic-lts-trusty – 3.13.0.116.107