LSN-0070-1: Kernel Live Patch Security Notice

17 August 2020

Linux kernel vulnerabilities

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

  • Ubuntu 18.04 LTS
  • Ubuntu 20.04 LTS
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 ESM

Summary

A security issue was fixed in the kernel.

Software Description

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-oem - Linux kernel for OEM systems

Details

Mauricio Faria de Oliveira discovered that the aufs implementation in the Linux kernel improperly managed inode reference counts in the vfsub_dentry_open() method. A local attacker could use this vulnerability to cause a denial of service. (CVE-2020-11935)

Update instructions

The problem can be corrected by updating your kernel livepatch to the following versions:

Ubuntu 18.04 LTS
aws - 70.1
generic - 70.1
lowlatency - 70.1
oem - 70.1
Ubuntu 20.04 LTS
aws - 70.1
azure - 70.1
gcp - 70.1
generic - 70.1
lowlatency - 70.1
Ubuntu 16.04 LTS
aws - 70.1
azure - 70.1
generic - 70.1
lowlatency - 70.1
Ubuntu 14.04 ESM
generic - 70.1
lowlatency - 70.1

Support Information

Kernels older than the levels listed below do not receive livepatch updates. If you are running a kernel version earlier than the one listed below, please upgrade your kernel as soon as possible.

Ubuntu 18.04 LTS
linux-aws - 4.15.0-1054
linux-azure - 5.0.0-1025
linux-gcp - 5.0.0-1025
linux-oem - 4.15.0-1063
linux - 4.15.0-69
Ubuntu 20.04 LTS
linux-aws - 5.4.0-1009
linux-azure - 5.4.0-1010
linux-gcp - 5.4.0-1009
linux-oem - 5.4.0-26
linux - 5.4.0-26
Ubuntu 16.04 LTS
linux-aws - 4.4.0-1098
linux-azure - 4.15.0-1063
linux-hwe - 4.15.0-69
linux - 4.4.0-168
Ubuntu 14.04 ESM
linux-lts-xenial - 4.4.0-168

References