==========================================================================
Ubuntu Security Notice USN-3903-1
March 06, 2019

linux, linux-azure, linux-gcp, linux-kvm, linux-raspi2 vulnerabilities
==========================================================================

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

- Ubuntu 18.10

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-kvm: Linux kernel for cloud environments
- linux-raspi2: Linux kernel for Raspberry Pi 2

Details:

Jason Wang discovered that the vhost net driver in the Linux kernel
contained an out of bounds write vulnerability. An attacker in a guest
virtual machine could use this to cause a denial of service (host system
crash) or possibly execute arbitrary code in the host kernel.
(CVE-2018-16880)

Jann Horn discovered that the userfaultd implementation in the Linux kernel
did not properly restrict access to certain ioctls. A local attacker could
use this possibly to modify files. (CVE-2018-18397)

Jann Horn discovered a race condition in the fork() system call in the
Linux kernel. A local attacker could use this to gain access to services
that cache authorizations. (CVE-2019-6133)

Update instructions:

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

Ubuntu 18.10:
  linux-image-4.18.0-1007-gcp     4.18.0-1007.8
  linux-image-4.18.0-1008-kvm     4.18.0-1008.8
  linux-image-4.18.0-1010-raspi2  4.18.0-1010.12
  linux-image-4.18.0-1013-azure   4.18.0-1013.13
  linux-image-4.18.0-16-generic   4.18.0-16.17
  linux-image-4.18.0-16-generic-lpae  4.18.0-16.17
  linux-image-4.18.0-16-lowlatency  4.18.0-16.17
  linux-image-4.18.0-16-snapdragon  4.18.0-16.17
  linux-image-azure               4.18.0.1013.14
  linux-image-gcp                 4.18.0.1007.7
  linux-image-generic             4.18.0.16.17
  linux-image-generic-lpae        4.18.0.16.17
  linux-image-gke                 4.18.0.1007.7
  linux-image-kvm                 4.18.0.1008.8
  linux-image-lowlatency          4.18.0.16.17
  linux-image-raspi2              4.18.0.1010.7
  linux-image-snapdragon          4.18.0.16.17

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://usn.ubuntu.com/usn/usn-3903-1
  CVE-2018-16880, CVE-2018-18397, CVE-2019-6133

Package Information:
  https://launchpad.net/ubuntu/+source/linux/4.18.0-16.17
  https://launchpad.net/ubuntu/+source/linux-azure/4.18.0-1013.13
  https://launchpad.net/ubuntu/+source/linux-gcp/4.18.0-1007.8
  https://launchpad.net/ubuntu/+source/linux-kvm/4.18.0-1008.8
  https://launchpad.net/ubuntu/+source/linux-raspi2/4.18.0-1010.12