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

Releases

• Ubuntu 14.04 ESM

Packages

• 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

• 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

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

• https://launchpad.net/bugs/1741934
• https://usn.ubuntu.com/usn/usn-3522-2