1. Ubuntu Security Notices
  2. USN-4465-1

USN-4465-1: linux kernel vulnerabilities

Publication date

23 August 2020

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

  • linux-aws-5.3 - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure-5.3 - Linux kernel for Microsoft Azure cloud systems
  • linux-gke-5.3 - Linux kernel for Google Container Engine (GKE) systems
  • linux-hwe - Linux hardware enablement (HWE) kernel

Details

It was discovered that the XFS file system implementation in the Linux
kernel did not properly validate meta data in some circumstances. An
attacker could use this to construct a malicious XFS image that, when
mounted, could cause a denial of service. (CVE-2020-12655)

It was discovered that the bcache subsystem in the Linux kernel did not
properly release a lock in some error conditions. A local attacker could
possibly use this to cause a denial of service. (CVE-2020-12771)

Kyungtae Kim discovered that the USB testing driver in the Linux kernel did
not properly deallocate memory on disconnect events. A physically proximate
attacker could use this to cause a denial of service (memory exhaustion).
(CVE-2020-15393)

It was discovered that the XFS file system implementation in the Linux
kernel did not properly validate meta data in some circumstances. An
attacker could use this to construct a malicious XFS image that, when
mounted, could cause a denial of service. (CVE-2020-12655)

It was discovered that the bcache subsystem in the Linux kernel did not
properly release a lock in some error conditions. A local attacker could
possibly use this to cause a denial of service. (CVE-2020-12771)

Kyungtae Kim discovered that the USB testing driver in the Linux kernel did
not properly deallocate memory on disconnect events. A physically proximate
attacker could use this to cause a denial of service (memory exhaustion).
(CVE-2020-15393)

Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

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.

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

Ubuntu Release Package Version
18.04 bionic linux-image-5.3.0-1033-aws –  5.3.0-1033.35
linux-image-5.3.0-1033-gke –  5.3.0-1033.35
linux-image-5.3.0-1035-azure –  5.3.0-1035.36
linux-image-5.3.0-65-generic –  5.3.0-65.59
linux-image-5.3.0-65-lowlatency –  5.3.0-65.59
linux-image-aws –  5.3.0.1033.32
linux-image-azure –  5.3.0.1035.31
linux-image-gke-5.3 –  5.3.0.1033.18
linux-image-gkeop-5.3 –  5.3.0.65.121

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References

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