USN-3522-3: Linux kernel regression

Releases

• Ubuntu 16.04 ESM

Packages

• linux - Linux kernel

Details

USN-3522-1 fixed a vulnerability in the Linux kernel 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 16.04

• linux-image-4.4.0-109-generic - 4.4.0-109.132
• linux-image-4.4.0-109-lowlatency - 4.4.0-109.132

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