USN-3220-2: Linux kernel (Xenial HWE) vulnerability

Ubuntu Security Notice USN-3220-2

7th March, 2017

linux-lts-xenial vulnerability

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

  • Ubuntu 14.04 LTS

Summary

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

Software description

  • linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty

Details

USN-3220-1 fixed vulnerabilities in the Linux kernel for Ubuntu 16.04
LTS. This update provides the corresponding updates for the Linux
Hardware Enablement (HWE) kernel from Ubuntu 16.04 LTS for Ubuntu
14.04 LTS.

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 14.04 LTS:
linux-image-powerpc-smp-lts-xenial 4.4.0.66.52
linux-image-generic-lpae-lts-xenial 4.4.0.66.52
linux-image-4.4.0-66-powerpc64-emb 4.4.0-66.87~14.04.1
linux-image-4.4.0-66-generic 4.4.0-66.87~14.04.1
linux-image-lowlatency-lts-xenial 4.4.0.66.52
linux-image-4.4.0-66-powerpc64-smp 4.4.0-66.87~14.04.1
linux-image-4.4.0-66-generic-lpae 4.4.0-66.87~14.04.1
linux-image-powerpc64-smp-lts-xenial 4.4.0.66.52
linux-image-4.4.0-66-lowlatency 4.4.0-66.87~14.04.1
linux-image-4.4.0-66-powerpc-smp 4.4.0-66.87~14.04.1
linux-image-generic-lts-xenial 4.4.0.66.52
linux-image-powerpc64-emb-lts-xenial 4.4.0.66.52
linux-image-4.4.0-66-powerpc-e500mc 4.4.0-66.87~14.04.1
linux-image-powerpc-e500mc-lts-xenial 4.4.0.66.52

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