USN-3522-4: Linux kernel (Xenial HWE) regression

10 January 2018

linux-lts-xenial regression

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

  • Ubuntu 14.04 LTS

Summary

USN-3522-2 introduced a regression in the Linux Hardware Enablement kernel.

Software Description

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

Details

USN-3522-2 fixed a vulnerability in the Linux Hardware Enablement kernel for Ubuntu 14.04 LTS to address Meltdown (CVE-2017-5754). Unfortunately, that update introduced a regression where a few systems failed to boot successfully. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Jann Horn discovered that microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Meltdown. A local attacker could use this to expose sensitive information, including kernel memory.

Update instructions

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

Ubuntu 14.04 LTS
linux-image-4.4.0-109-generic - 4.4.0-109.132~14.04.1
linux-image-4.4.0-109-lowlatency - 4.4.0-109.132~14.04.1
linux-image-generic-lts-xenial - 4.4.0.109.92
linux-image-lowlatency-lts-xenial - 4.4.0.109.92

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