USN-3220-1: Linux kernel vulnerability

Ubuntu Security Notice USN-3220-1

7th March, 2017

linux, linux-gke, linux-raspi2, linux-snapdragon vulnerability

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

  • Ubuntu 16.04 LTS

Summary

The system could be made to crash or run programs as an administrator.

Software description

  • linux - Linux kernel
  • linux-gke - Linux Kernel for Google Container Engine (GKE) systems
  • linux-raspi2 - Linux kernel for Raspberry Pi 2
  • linux-snapdragon - Linux kernel for Snapdragon Processors

Details

Alexander Popov discovered that the N_HDLC line discipline implementation
in the Linux kernel contained a double-free vulnerability. A local attacker
could use this to cause a denial of service (system crash) or possibly gain
administrative privileges.

Update instructions

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

Ubuntu 16.04 LTS:
linux-image-gke 4.4.0.1005.5
linux-image-4.4.0-1005-gke 4.4.0-1005.6
linux-image-raspi2 4.4.0.1046.45
linux-image-4.4.0-66-powerpc64-emb 4.4.0-66.87
linux-image-4.4.0-66-generic 4.4.0-66.87
linux-image-powerpc-smp 4.4.0.66.70
linux-image-generic 4.4.0.66.70
linux-image-powerpc-e500mc 4.4.0.66.70
linux-image-4.4.0-66-powerpc64-smp 4.4.0-66.87
linux-image-lowlatency 4.4.0.66.70
linux-image-4.4.0-66-generic-lpae 4.4.0-66.87
linux-image-4.4.0-66-lowlatency 4.4.0-66.87
linux-image-powerpc64-smp 4.4.0.66.70
linux-image-4.4.0-66-powerpc-smp 4.4.0-66.87
linux-image-generic-lpae 4.4.0.66.70
linux-image-snapdragon 4.4.0.1050.42
linux-image-4.4.0-66-powerpc-e500mc 4.4.0-66.87
linux-image-powerpc64-emb 4.4.0.66.70
linux-image-4.4.0-1046-raspi2 4.4.0-1046.53
linux-image-4.4.0-1050-snapdragon 4.4.0-1050.54

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

CVE-2017-2636