[USN-3444-2] Linux kernel (Xenial HWE) vulnerabilities

[Steve Beattie]

==========================================================================
Ubuntu Security Notice USN-3444-2
October 10, 2017

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 Linux kernel.

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

Details:

USN-3444-1 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.

Jan H. Schönherr discovered that the Xen subsystem did not properly handle
block IO merges correctly in some situations. An attacker in a guest vm
could use this to cause a denial of service (host crash) or possibly gain
administrative privileges in the host. (CVE-2017-12134)

Andrey Konovalov discovered that a divide-by-zero error existed in the TCP
stack implementation in the Linux kernel. A local attacker could use this
to cause a denial of service (system crash). (CVE-2017-14106)

Otto Ebeling discovered that the memory manager in the Linux kernel did not
properly check the effective UID in some situations. A local attacker could
use this to expose sensitive information. (CVE-2017-14140)

Update instructions:

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

Ubuntu 14.04 LTS:
  linux-image-4.4.0-97-generic    4.4.0-97.120~14.04.1
  linux-image-4.4.0-97-generic-lpae  4.4.0-97.120~14.04.1
  linux-image-4.4.0-97-lowlatency  4.4.0-97.120~14.04.1
  linux-image-4.4.0-97-powerpc-e500mc  4.4.0-97.120~14.04.1
  linux-image-4.4.0-97-powerpc-smp  4.4.0-97.120~14.04.1
  linux-image-4.4.0-97-powerpc64-emb  4.4.0-97.120~14.04.1
  linux-image-4.4.0-97-powerpc64-smp  4.4.0-97.120~14.04.1
  linux-image-generic-lpae-lts-xenial  4.4.0.97.81
  linux-image-generic-lts-xenial  4.4.0.97.81
  linux-image-lowlatency-lts-xenial  4.4.0.97.81
  linux-image-powerpc-e500mc-lts-xenial  4.4.0.97.81
  linux-image-powerpc-smp-lts-xenial  4.4.0.97.81
  linux-image-powerpc64-emb-lts-xenial  4.4.0.97.81
  linux-image-powerpc64-smp-lts-xenial  4.4.0.97.81

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:
  https://www.ubuntu.com/usn/usn-3444-2
  https://www.ubuntu.com/usn/usn-3444-1
  CVE-2017-12134, CVE-2017-14106, CVE-2017-14140

Package Information:
  https://launchpad.net/ubuntu/+source/linux-lts-xenial/4.4.0-97.120~14.04.1

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