USN-2846-1: Linux kernel vulnerabilities

Ubuntu Security Notice USN-2846-1

19th December, 2015

linux vulnerabilities

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

• Ubuntu 12.04 LTS

Summary

Several security issues were fixed in the kernel.

Software description

• linux
  – Linux kernel

Details

Felix Wilhelm discovered a race condition in the Xen paravirtualized
drivers which can cause double fetch vulnerabilities. An attacker in the
paravirtualized guest could exploit this flaw to cause a denial of service
(crash the host) or potentially execute arbitrary code on the host.
(CVE-2015-8550)

Konrad Rzeszutek Wilk discovered the Xen PCI backend driver does not
perform sanity checks on the device's state. An attacker could exploit this
flaw to cause a denial of service (NULL dereference) on the host.
(CVE-2015-8551)

Konrad Rzeszutek Wilk discovered the Xen PCI backend driver does not
perform sanity checks on the device's state. An attacker could exploit this
flaw to cause a denial of service by flooding the logging system with
WARN() messages causing the initial domain to exhaust disk space.
(CVE-2015-8552)

Update instructions

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

Ubuntu 12.04 LTS:

linux-image-3.2.0-97-highbank

3.2.0-97.137

linux-image-3.2.0-97-omap

3.2.0-97.137

linux-image-3.2.0-97-generic-pae

3.2.0-97.137

linux-image-3.2.0-97-powerpc64-smp

3.2.0-97.137

linux-image-3.2.0-97-virtual

3.2.0-97.137

linux-image-3.2.0-97-generic

3.2.0-97.137

linux-image-3.2.0-97-powerpc-smp

3.2.0-97.137

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

CVE-2015-8550,

CVE-2015-8551,

CVE-2015-8552

Source: ubuntu-usn