USN-4343-1: Linux kernel vulnerability

28 April 2020

linux vulnerability

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

  • Ubuntu 20.04 LTS

Summary

Systems running on s390x architecture could be made to crash or run programs as an administrator under certain conditions.

Software Description

  • linux - Linux kernel

Details

Al Viro discovered that the Linux kernel for s390x systems did not properly perform page table upgrades for kernel sections that use secondary address mode. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code.

Update instructions

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

Ubuntu 20.04 LTS
linux-image-5.4.0-28-generic - 5.4.0-28.32
linux-image-5.4.0-28-generic-lpae - 5.4.0-28.32
linux-image-5.4.0-28-lowlatency - 5.4.0-28.32
linux-image-generic - 5.4.0.28.33
linux-image-generic-lpae - 5.4.0.28.33
linux-image-lowlatency - 5.4.0.28.33
linux-image-oem - 5.4.0.28.33
linux-image-oem-osp1 - 5.4.0.28.33
linux-image-virtual - 5.4.0.28.33

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