USN-3903-1: Linux kernel vulnerabilities

6 March 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

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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