USN-2946-2: Linux kernel (Trusty HWE) vulnerabilities

Ubuntu Security Notice USN-2946-2

6th April, 2016

linux-lts-trusty 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-lts-trusty - Linux hardware enablement kernel from Trusty for Precise

Details

Venkatesh Pottem discovered a use-after-free vulnerability in the Linux
kernel's CXGB3 driver. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2015-8812)

Xiaofei Rex Guo discovered a timing side channel vulnerability in the Linux
Extended Verification Module (EVM). An attacker could use this to affect
system integrity. (CVE-2016-2085)

David Herrmann discovered that the Linux kernel incorrectly accounted file
descriptors to the original opener for in-flight file descriptors sent over
a unix domain socket. A local attacker could use this to cause a denial of
service (resource exhaustion). (CVE-2016-2550)

It was discovered that the Linux kernel did not enforce limits on the
amount of data allocated to buffer pipes. A local attacker could use this
to cause a denial of service (resource exhaustion). (CVE-2016-2847)

Update instructions

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

Ubuntu 12.04 LTS:

linux-image-3.13.0-85-generic 3.13.0-85.129~precise1

linux-image-3.13.0-85-generic-lpae 3.13.0-85.129~precise1

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-2015-8812, CVE-2016-2085, CVE-2016-2550, CVE-2016-2847