Ubuntu Security Notice 2806-1 - 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.
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==========================================================================Ubuntu Security Notice USN-2806-1
November 10, 2015
linux-lts-vivid 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-vivid: Linux hardware enablement kernel from Vivid
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 versions:
Ubuntu 14.04 LTS:
linux-image-3.19.0-33-generic 3.19.0-33.38~14.04.1
linux-image-3.19.0-33-generic-lpae 3.19.0-33.38~14.04.1
linux-image-3.19.0-33-lowlatency 3.19.0-33.38~14.04.1
linux-image-3.19.0-33-powerpc-e500mc 3.19.0-33.38~14.04.1
linux-image-3.19.0-33-powerpc-smp 3.19.0-33.38~14.04.1
linux-image-3.19.0-33-powerpc64-emb 3.19.0-33.38~14.04.1
linux-image-3.19.0-33-powerpc64-smp 3.19.0-33.38~14.04.1
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. 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:
http://www.ubuntu.com/usn/usn-2806-1
CVE-2015-5307
Package Information:
https://launchpad.net/ubuntu/+source/linux-lts-vivid/3.19.0-33.38~14.04.1