Ubuntu 18.04 LTS USN-4301-1: Critical Kernel Issues Resolved

ubuntu

March 16, 2020

Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

- linux-aws-5.0: Linux kernel for Amazon Web Services (AWS) systems

- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems

- linux-gke-5.0: Linux kernel for Google Container Engine (GKE) systems

- linux-oracle-5.0: Linux kernel for Oracle Cloud systems

Details:

It was discovered that the KVM implementation in the Linux kernel, when

paravirtual TLB flushes are enabled in guests, the hypervisor in some

situations could miss deferred TLB flushes or otherwise mishandle them. An

attacker in a guest VM could use this to expose sensitive information (read

memory from another guest VM). (CVE-2019-3016)

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. (CVE-2020-2732)

It was discovered that...

Read the Full Advisory

Topics Covered

security advisory denial of service CVE fix ubuntu cloud security linux kernel

Update Instructions

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

Ubuntu 18.04 LTS:
  linux-image-5.0.0-1013-oracle   5.0.0-1013.18
  linux-image-5.0.0-1027-aws      5.0.0-1027.30
  linux-image-5.0.0-1032-gke      5.0.0-1032.33
  linux-image-5.0.0-1033-gcp      5.0.0-1033.34
  linux-image-aws-edge            5.0.0.1027.41
  linux-image-gcp                 5.0.0.1033.37
  linux-image-gke-5.0             5.0.0.1032.20
  linux-image-oracle              5.0.0.1013.13

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.