1. Ubuntu Security Notices
  2. USN-4303-1

USN-4303-1: Linux kernel vulnerability

Publication date

17 March 2020

Overview

The system could be made to expose sensitive information.

Releases

Packages

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-kvm - Linux kernel for cloud environments

Details

Paulo Bonzini discovered that the KVM hypervisor implementation in the
Linux kernel could improperly let a nested (level 2) guest access the
resources of a parent (level 1) guest in certain situations. An attacker
could use this to expose sensitive information.

Paulo Bonzini discovered that the KVM hypervisor implementation in the
Linux kernel could improperly let a nested (level 2) guest access the
resources of a parent (level 1) guest in certain situations. An attacker
could use this to expose sensitive information.

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
16.04 xenial linux-image-4.4.0-1068-kvm –  4.4.0-1068.75
linux-image-4.4.0-1104-aws –  4.4.0-1104.115
linux-image-4.4.0-176-generic –  4.4.0-176.206
linux-image-4.4.0-176-generic-lpae –  4.4.0-176.206
linux-image-4.4.0-176-lowlatency –  4.4.0-176.206
linux-image-4.4.0-176-powerpc-e500mc –  4.4.0-176.206
linux-image-4.4.0-176-powerpc-smp –  4.4.0-176.206
linux-image-4.4.0-176-powerpc64-emb –  4.4.0-176.206
linux-image-4.4.0-176-powerpc64-smp –  4.4.0-176.206
linux-image-aws –  4.4.0.1104.108
linux-image-generic –  4.4.0.176.184
linux-image-generic-lpae –  4.4.0.176.184
linux-image-kvm –  4.4.0.1068.68
linux-image-lowlatency –  4.4.0.176.184
linux-image-powerpc-e500mc –  4.4.0.176.184
linux-image-powerpc-smp –  4.4.0.176.184
linux-image-powerpc64-emb –  4.4.0.176.184
linux-image-powerpc64-smp –  4.4.0.176.184
linux-image-virtual –  4.4.0.176.184

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References

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