USN-2979-1: Linux kernel vulnerabilities

Ubuntu Security Notice USN-2979-1

16th May, 2016

linux vulnerabilities

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

  • Ubuntu 16.04 LTS

Summary

Several security issues were fixed in the kernel.

Software description

  • linux - Linux kernel

Details

David Matlack discovered that the Kernel-based Virtual Machine (KVM)
implementation in the Linux kernel did not properly restrict variable
Memory Type Range Registers (MTRR) in KVM guests. A privileged user in a
guest VM could use this to cause a denial of service (system crash) in the
host, expose sensitive information from the host, or possibly gain
administrative privileges in the host. (CVE-2016-3713)

Philip Pettersson discovered that the Linux kernel's ASN.1 DER decoder did
not properly process certificate files with tags of indefinite length. A
local unprivileged attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code with administrative
privileges. (CVE-2016-0758)

Update instructions

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

Ubuntu 16.04 LTS:
linux-image-4.4.0-22-powerpc-e500mc 4.4.0-22.40
linux-image-4.4.0-22-powerpc64-smp 4.4.0-22.40
linux-image-4.4.0-22-generic-lpae 4.4.0-22.40
linux-image-4.4.0-22-lowlatency 4.4.0-22.40
linux-image-4.4.0-22-powerpc-smp 4.4.0-22.40
linux-image-4.4.0-22-generic 4.4.0-22.40
linux-image-4.4.0-22-powerpc64-emb 4.4.0-22.40

To update your system, please follow these instructions: http://ift.tt/17VXqjU.

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-2016-0758, CVE-2016-3713



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