USN-3548-2: Linux kernel (HWE) vulnerability

26 January 2018

linux-hwe, linux-azure, linux-gcp, linux-oem vulnerability

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

  • Ubuntu 16.04 LTS

Summary

The system could be made to crash or run programs as an administrator.

Software Description

  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-hwe - Linux hardware enablement (HWE) kernel
  • linux-oem - Linux kernel for OEM processors

Details

USN-3548-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 17.10 for Ubuntu 16.04 LTS.

Jay Vosburgh discovered a logic error in the x86-64 syscall entry implementation in the Linux kernel, introduced as part of the mitigations for the Spectre vulnerability. A local attacker could use this to cause a denial of service or possibly execute arbitrary code.

Update instructions

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

Ubuntu 16.04 LTS
linux-image-4.13.0-1007-azure - 4.13.0-1007.9
linux-image-4.13.0-1008-gcp - 4.13.0-1008.11
linux-image-4.13.0-1019-oem - 4.13.0-1019.20
linux-image-4.13.0-32-generic - 4.13.0-32.35~16.04.1
linux-image-4.13.0-32-lowlatency - 4.13.0-32.35~16.04.1
linux-image-azure - 4.13.0.1007.8
linux-image-gcp - 4.13.0.1008.10
linux-image-generic-hwe-16.04 - 4.13.0.32.52
linux-image-gke - 4.13.0.1008.10
linux-image-lowlatency-hwe-16.04 - 4.13.0.32.52
linux-image-oem - 4.13.0.1019.23

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