USN-3160-2: Linux kernel (Trusty HWE) vulnerabilities

Ubuntu Security Notice USN-3160-2

20th December, 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

USN-3160-1 fixed vulnerabilities in the Linux kernel for Ubuntu 14.04
LTS. This update provides the corresponding updates for the Linux
Hardware Enablement (HWE) kernel from Ubuntu 14.04 LTS for Ubuntu
12.04 LTS.

CAI Qian discovered that shared bind mounts in a mount namespace
exponentially added entries without restriction to the Linux kernel's mount
table. A local attacker could use this to cause a denial of service (system
crash). (CVE-2016-6213)

It was discovered that a race condition existed in the procfs
environ_read function in the Linux kernel, leading to an integer
underflow. A local attacker could use this to expose sensitive
information (kernel memory). (CVE-2016-7916)

Update instructions

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

Ubuntu 12.04 LTS:
linux-image-3.13.0-106-generic 3.13.0-106.153~precise1
linux-image-generic-lpae-lts-trusty 3.13.0.106.97
linux-image-3.13.0-106-generic-lpae 3.13.0-106.153~precise1
linux-image-generic-lts-trusty 3.13.0.106.97

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-2016-6213, CVE-2016-7916