1. Ubuntu Security Notices
  2. USN-3903-1

USN-3903-1: Linux kernel vulnerabilities

Publication date

6 March 2019

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

  • 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)

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

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

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.

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

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

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References

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