==========================================================================
Ubuntu Security Notice USN-3405-1
August 28, 2017

linux, linux-aws, linux-gke, linux-raspi2, linux-snapdragon 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: Linux kernel
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-gke: Linux kernel for Google Container Engine (GKE) systems
- linux-raspi2: Linux kernel for Raspberry Pi 2
- linux-snapdragon: Linux kernel for Snapdragon processors

Details:

It was discovered that a use-after-free vulnerability existed in the POSIX
message queue implementation in the Linux kernel. A local attacker could
use this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2017-11176)

Huang Weller discovered that the ext4 filesystem implementation in the
Linux kernel mishandled a needs-flushing-before-commit list. A local
attacker could use this to expose sensitive information. (CVE-2017-7495)

It was discovered that a buffer overflow existed in the Broadcom FullMAC
WLAN driver in the Linux kernel. A local attacker could use this to cause a
denial of service (system crash) or possibly execute arbitrary code.
(CVE-2017-7541)

It was discovered that the Linux kernel did not honor the UEFI secure boot
mode when performing a kexec operation. A local attacker could use this to
bypass secure boot restrictions. (CVE-2015-7837)

Update instructions:

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

Ubuntu 16.04 LTS:
  linux-image-4.4.0-1028-gke      4.4.0-1028.28
  linux-image-4.4.0-1032-aws      4.4.0-1032.41
  linux-image-4.4.0-1071-raspi2   4.4.0-1071.79
  linux-image-4.4.0-1073-snapdragon  4.4.0-1073.78
  linux-image-4.4.0-93-generic    4.4.0-93.116
  linux-image-4.4.0-93-generic-lpae  4.4.0-93.116
  linux-image-4.4.0-93-lowlatency  4.4.0-93.116
  linux-image-4.4.0-93-powerpc-e500mc  4.4.0-93.116
  linux-image-4.4.0-93-powerpc-smp  4.4.0-93.116
  linux-image-4.4.0-93-powerpc64-emb  4.4.0-93.116
  linux-image-4.4.0-93-powerpc64-smp  4.4.0-93.116
  linux-image-aws                 4.4.0.1032.34
  linux-image-generic             4.4.0.93.98
  linux-image-generic-lpae        4.4.0.93.98
  linux-image-gke                 4.4.0.1028.29
  linux-image-lowlatency          4.4.0.93.98
  linux-image-powerpc-smp         4.4.0.93.98
  linux-image-powerpc64-emb       4.4.0.93.98
  linux-image-powerpc64-smp       4.4.0.93.98
  linux-image-raspi2              4.4.0.1071.71
  linux-image-snapdragon          4.4.0.1073.65

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-3405-1
  CVE-2015-7837, CVE-2017-11176, CVE-2017-7495, CVE-2017-7541

Package Information:
  https://launchpad.net/ubuntu/+source/linux/4.4.0-93.116
  https://launchpad.net/ubuntu/+source/linux-aws/4.4.0-1032.41
  https://launchpad.net/ubuntu/+source/linux-gke/4.4.0-1028.28
  https://launchpad.net/ubuntu/+source/linux-raspi2/4.4.0-1071.79
  https://launchpad.net/ubuntu/+source/linux-snapdragon/4.4.0-1073.78