Ubuntu 20.04 & 18.04 LTS USN-5116-1 Critical: Kernel Risks

ubuntu

October 20, 2021

Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

- linux: Linux kernel

- linux-bluefield: Linux kernel for NVIDIA BlueField platforms

- linux-kvm: Linux kernel for cloud environments

- linux-gcp-5.4: Linux kernel for Google Cloud Platform (GCP) systems

- linux-hwe-5.4: Linux hardware enablement (HWE) kernel

Details:

It was discovered that a race condition existed in the Atheros Ath9k WiFi

driver in the Linux kernel. An attacker could possibly use this to expose

sensitive information (WiFi network traffic). (CVE-2020-3702)

Alois Wohlschlager discovered that the overlay file system in the Linux

kernel did not restrict private clones in some situations. An attacker

could use this to expose sensitive information. (CVE-2021-3732)

It was discovered that the KVM hypervisor implementation in the Linux

kernel did not properly compute the access permissions for shadow pages in

some situations. A local attacker could use this to cause a denial of

service. (CV...

Read the Full Advisory

Topics Covered

security advisory denial of service critical kernel system update information exposure ubuntu

Update Instructions

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

Ubuntu 20.04 LTS:
  linux-image-5.4.0-1020-bluefield  5.4.0-1020.23
  linux-image-5.4.0-1048-kvm      5.4.0-1048.50
  linux-image-5.4.0-89-generic    5.4.0-89.100
  linux-image-5.4.0-89-generic-lpae  5.4.0-89.100
  linux-image-5.4.0-89-lowlatency  5.4.0-89.100
  linux-image-bluefield           5.4.0.1020.21
  linux-image-generic             5.4.0.89.93
  linux-image-generic-lpae        5.4.0.89.93
  linux-image-kvm                 5.4.0.1048.47
  linux-image-lowlatency          5.4.0.89.93
  linux-image-oem                 5.4.0.89.93
  linux-image-oem-osp1            5.4.0.89.93
  linux-image-virtual             5.4.0.89.93

Ubuntu 18.04 LTS:
  linux-image-5.4.0-1055-gcp      5.4.0-1055.59~18.04.1
  linux-image-5.4.0-89-generic    5.4.0-89.100~18.04.1
  linux-image-5.4.0-89-generic-lpae  5.4.0-89.100~18.04.1
  linux-image-5.4.0-89-lowlatency  5.4.0-89.100~18.04.1
  linux-image-gcp                 5.4.0.1055.41
  linux-image-generic-hwe-18.04   5.4.0.89.100~18.04.79
  linux-image-generic-lpae-hwe-18.04  5.4.0.89.100~18.04.79
  linux-image-lowlatency-hwe-18.04  5.4.0.89.100~18.04.79
  linux-image-oem                 5.4.0.89.100~18.04.79
  linux-image-oem-osp1            5.4.0.89.100~18.04.79
  linux-image-snapdragon-hwe-18.04  5.4.0.89.100~18.04.79
  linux-image-virtual-hwe-18.04   5.4.0.89.100~18.04.79

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.