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Ubuntu Security Notice USN-3443-2
October 10, 2017

linux-hwe vulnerabilities
==========================================================================

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

- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-hwe: Linux hardware enablement (HWE) kernel

Details:

USN-3443-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.04.
This update provides the corresponding updates for the Linux Hardware
Enablement (HWE) kernel from Ubuntu 17.04 for Ubuntu 16.04 LTS.

It was discovered that on the PowerPC architecture, the kernel did not
properly sanitize the signal stack when handling sigreturn(). A local
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2017-1000255)

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)

Update instructions:

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

Ubuntu 16.04 LTS:
  linux-image-4.10.0-37-generic   4.10.0-37.41~16.04.1
  linux-image-4.10.0-37-generic-lpae  4.10.0-37.41~16.04.1
  linux-image-4.10.0-37-lowlatency  4.10.0-37.41~16.04.1
  linux-image-generic-hwe-16.04   4.10.0.37.39
  linux-image-generic-lpae-hwe-16.04  4.10.0.37.39
  linux-image-lowlatency-hwe-16.04  4.10.0.37.39

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-3443-2
  https://www.ubuntu.com/usn/usn-3443-1
  CVE-2017-1000255, CVE-2017-14106

Package Information:
  https://launchpad.net/ubuntu/+source/linux-hwe/4.10.0-37.41~16.04.1