[USN-3084-2] Linux kernel (Xenial HWE) vulnerabilities

[Steve Beattie]

==========================================================================
Ubuntu Security Notice USN-3084-2
September 19, 2016

linux-lts-xenial vulnerabilities
==========================================================================

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

- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty

Details:

USN-3084-1 fixed vulnerabilities in the Linux kernel for Ubuntu
16.04 LTS. This update provides the corresponding updates for the
Linux Hardware Enablement (HWE) kernel from Ubuntu 16.04 LTS for
Ubuntu 14.04 LTS.

Pengfei Wang discovered a race condition in the audit subsystem in the
Linux kernel. A local attacker could use this to corrupt audit logs or
disrupt system-call auditing. (CVE-2016-6136)

It was discovered that the powerpc and powerpc64 hypervisor-mode KVM
implementation in the Linux kernel for did not properly maintain state
about transactional memory. An unprivileged attacker in a guest could cause
a denial of service (CPU lockup) in the host OS. (CVE-2016-5412)

Pengfei Wang discovered a race condition in the Chrome OS embedded
controller device driver in the Linux kernel. A local attacker could use
this to cause a denial of service (system crash). (CVE-2016-6156)

Update instructions:

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

Ubuntu 14.04 LTS:
  linux-image-4.4.0-38-generic    4.4.0-38.57~14.04.1
  linux-image-4.4.0-38-generic-lpae  4.4.0-38.57~14.04.1
  linux-image-4.4.0-38-lowlatency  4.4.0-38.57~14.04.1
  linux-image-4.4.0-38-powerpc-e500mc  4.4.0-38.57~14.04.1
  linux-image-4.4.0-38-powerpc-smp  4.4.0-38.57~14.04.1
  linux-image-4.4.0-38-powerpc64-emb  4.4.0-38.57~14.04.1
  linux-image-4.4.0-38-powerpc64-smp  4.4.0-38.57~14.04.1

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.
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:
  http://www.ubuntu.com/usn/usn-3084-2
  http://www.ubuntu.com/usn/usn-3084-1
  CVE-2016-5412, CVE-2016-6136, CVE-2016-6156

Package Information:
  https://launchpad.net/ubuntu/+source/linux-lts-xenial/4.4.0-38.57~14.04.1

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