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

5 April 2017

linux-hwe, linux-lts-trusty, linux-lts-xenial vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS

Summary

The system could be made to crash under certain conditions.

Software Description

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

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

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

Ubuntu 16.04 LTS
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
linux-image-generic-hwe-16.04 - 4.8.0.46.18
linux-image-generic-lpae-hwe-16.04 - 4.8.0.46.18
linux-image-lowlatency-hwe-16.04 - 4.8.0.46.18
Ubuntu 14.04 LTS
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
linux-image-generic-lpae-lts-xenial - 4.4.0.72.59
linux-image-generic-lts-xenial - 4.4.0.72.59
linux-image-lowlatency-lts-xenial - 4.4.0.72.59
linux-image-powerpc-e500mc-lts-xenial - 4.4.0.72.59
linux-image-powerpc-smp-lts-xenial - 4.4.0.72.59
linux-image-powerpc64-smp-lts-xenial - 4.4.0.72.59
Ubuntu 12.04 LTS
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

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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

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.

References