USN-4325-1: Linux kernel vulnerabilities

7 April 2020

linux-azure, linux-gcp, linux-gke-5.0, linux-oem-osp1, linux-oracle-5.0 vulnerabilities

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

  • Ubuntu 18.04 LTS

Summary

Several security issues were fixed in the Linux kernel.

Software Description

  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gke-5.0 - Linux kernel for Google Container Engine (GKE) systems
  • linux-oem-osp1 - Linux kernel for OEM processors
  • linux-oracle-5.0 - Linux kernel for Oracle Cloud systems

Details

It was discovered that the IPMI message handler implementation in the Linux kernel did not properly deallocate memory in certain situations. A local attacker could use this to cause a denial of service (kernel memory exhaustion). (CVE-2019-19046)

Al Viro discovered that the vfs layer in the Linux kernel contained a use- after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly expose sensitive information (kernel memory). (CVE-2020-8428)

Update instructions

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

Ubuntu 18.04 LTS
linux-image-5.0.0-1014-oracle - 5.0.0-1014.19
linux-image-5.0.0-1033-gke - 5.0.0-1033.34
linux-image-5.0.0-1034-gcp - 5.0.0-1034.35
linux-image-5.0.0-1036-azure - 5.0.0-1036.38
linux-image-5.0.0-1047-oem-osp1 - 5.0.0-1047.52
linux-image-azure - 5.0.0.1036.47
linux-image-gcp - 5.0.0.1034.38
linux-image-gke-5.0 - 5.0.0.1033.21
linux-image-oem-osp1 - 5.0.0.1047.50
linux-image-oracle - 5.0.0.1014.15

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