[USN-4303-1] Linux kernel vulnerability

[Steve Beattie]

==========================================================================
Ubuntu Security Notice USN-4303-1
March 17, 2020

linux, linux-aws, linux-kvm vulnerability
==========================================================================

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

- Ubuntu 16.04 LTS

Summary:

The system could be made to expose sensitive information.

Software Description:
- 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.

Update instructions:

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

Ubuntu 16.04 LTS:
  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

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:
  https://usn.ubuntu.com/4303-1
  CVE-2020-2732

Package Information:
  https://launchpad.net/ubuntu/+source/linux/4.4.0-176.206
  https://launchpad.net/ubuntu/+source/linux-aws/4.4.0-1104.115
  https://launchpad.net/ubuntu/+source/linux-kvm/4.4.0-1068.75

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