1. Ubuntu Security Notices
  2. USN-4709-1

USN-4709-1: Linux kernel vulnerabilities

Publication date

2 February 2021

Overview

Several security issues were fixed in the Linux kernel.

Releases

Packages

  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-kvm - Linux kernel for cloud environments
  • linux-raspi2 - Linux kernel for Raspberry Pi (V8) systems
  • linux-snapdragon - Linux kernel for Qualcomm Snapdragon processors

Details

It was discovered that the LIO SCSI target implementation in the Linux
kernel performed insufficient identifier checking in certain XCOPY
requests. An attacker with access to at least one LUN in a multiple
backstore environment could use this to expose sensitive information or
modify data. (CVE-2020-28374)

Wen Xu discovered that the XFS filesystem implementation in the Linux
kernel did not properly track inode validations. An attacker could use this
to construct a malicious XFS image that, when mounted, could cause a denial
of service (system crash). (CVE-2018-13093)

It was discovered that the btrfs file system implementation in the Linux
kernel did not properly validate file system metadata in some situations.
An attacker could use this to construct a malicious btrfs image that, when
mounted, could cause a denial of service (system crash). (

It was discovered that the LIO SCSI target implementation in the Linux
kernel performed insufficient identifier checking in certain XCOPY
requests. An attacker with access to at least one LUN in a multiple
backstore environment could use this to expose sensitive information or
modify data. (CVE-2020-28374)

Wen Xu discovered that the XFS filesystem implementation in the Linux
kernel did not properly track inode validations. An attacker could use this
to construct a malicious XFS image that, when mounted, could cause a denial
of service (system crash). (CVE-2018-13093)

It was discovered that the btrfs file system implementation in the Linux
kernel did not properly validate file system metadata in some situations.
An attacker could use this to construct a malicious btrfs image that, when
mounted, could cause a denial of service (system crash). (CVE-2019-19813,
CVE-2019-19816)

Bodong Zhao discovered a use-after-free in the Sun keyboard driver
implementation in the Linux kernel. A local attacker could use this to
cause a denial of service or possibly execute arbitrary code.
(CVE-2020-25669)

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
16.04 xenial linux-image-4.4.0-1087-kvm –  4.4.0-1087.96
linux-image-4.4.0-1121-aws –  4.4.0-1121.135
linux-image-4.4.0-1145-raspi2 –  4.4.0-1145.155
linux-image-4.4.0-1149-snapdragon –  4.4.0-1149.159
linux-image-aws –  4.4.0.1121.126
linux-image-kvm –  4.4.0.1087.85
linux-image-raspi2 –  4.4.0.1145.145
linux-image-snapdragon –  4.4.0.1149.141
14.04 trusty linux-image-4.4.0-1085-aws –  4.4.0-1085.89
linux-image-aws –  4.4.0.1085.82

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Get Ubuntu Pro

References

Have additional questions?

Talk to a member of the team ›