USN-4031-1: Linux kernel vulnerability

24 June 2019

linux, linux-hwe vulnerability

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

  • Ubuntu 19.04
  • Ubuntu 18.10
  • Ubuntu 18.04 LTS

Summary

64-Bit PowerPC systems could be made to expose sensitive information.

Software Description

  • linux - Linux kernel
  • linux-hwe - Linux hardware enablement (HWE) kernel

Details

It was discovered that the Linux kernel did not properly separate certain memory mappings when creating new userspace processes on 64-bit Power (ppc64el) systems. A local attacker could use this to access memory contents or cause memory corruption of other processes on the system.

Update instructions

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

Ubuntu 19.04
linux-image-5.0.0-19-generic - 5.0.0-19.20
linux-image-generic - 5.0.0.19.20
linux-image-virtual - 5.0.0.19.20
Ubuntu 18.10
linux-image-4.18.0-24-generic - 4.18.0-24.25
linux-image-generic - 4.18.0.24.25
linux-image-powerpc-e500mc - 4.18.0.24.25
linux-image-powerpc-smp - 4.18.0.24.25
linux-image-powerpc64-emb - 4.18.0.24.25
linux-image-powerpc64-smp - 4.18.0.24.25
linux-image-virtual - 4.18.0.24.25
Ubuntu 18.04 LTS
linux-image-4.18.0-24-generic - 4.18.0-24.25~18.04.1
linux-image-generic-hwe-18.04 - 4.18.0.24.74
linux-image-virtual-hwe-18.04 - 4.18.0.24.74

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