USN-2807-1: Linux kernel (Wily HWE) vulnerability

Ubuntu Security Notice USN-2807-1

10th November, 2015

linux-lts-wily vulnerability

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

  • Ubuntu 14.04 LTS

Summary

The system could be made to crash under certain conditions.

Software description

  • linux-lts-wily
    – Linux hardware enablement kernel from Wily

Details

Ben Serebrin discovered that the KVM hypervisor implementation in the Linux
kernel did not properly catch Alignment Check exceptions. An attacker in a
guest virtual machine could use this to cause a denial of service (system
crash) in the host OS.

Update instructions

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

Ubuntu 14.04 LTS:
linux-image-4.2.0-18-lowlatency

4.2.0-18.22~14.04.1
linux-image-4.2.0-18-generic-lpae

4.2.0-18.22~14.04.1
linux-image-4.2.0-18-powerpc64-emb

4.2.0-18.22~14.04.1
linux-image-4.2.0-18-generic

4.2.0-18.22~14.04.1
linux-image-4.2.0-18-powerpc-e500mc

4.2.0-18.22~14.04.1
linux-image-4.2.0-18-powerpc64-smp

4.2.0-18.22~14.04.1
linux-image-4.2.0-18-powerpc-smp

4.2.0-18.22~14.04.1

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. If
you use linux-restricted-modules, you have to update that package as
well to get modules which work with the new kernel version. Unless you
manually uninstalled the standard kernel metapackages (e.g. linux-generic,
linux-server, linux-powerpc), a standard system upgrade will automatically
perform this as well.

References

CVE-2015-5307

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