USN-5267-2: Linux kernel regression

11 February 2022

Several security issues were fixed in the Linux kernel.

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Releases

Packages

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-aws-5.4 - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-azure-5.4 - Linux kernel for Microsoft Azure cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gcp-5.4 - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gke - Linux kernel for Google Container Engine (GKE) systems
  • linux-gke-5.4 - Linux kernel for Google Container Engine (GKE) systems
  • linux-gkeop - Linux kernel for Google Container Engine (GKE) systems
  • linux-gkeop-5.4 - Linux kernel for Google Container Engine (GKE) systems
  • linux-hwe-5.4 - Linux hardware enablement (HWE) kernel
  • linux-ibm - Linux kernel for IBM cloud systems
  • linux-kvm - Linux kernel for cloud environments
  • linux-oracle - Linux kernel for Oracle Cloud systems
  • linux-oracle-5.4 - Linux kernel for Oracle Cloud systems

Details

USN-5267-1 fixed vulnerabilities in the Linux kernel. Unfortunately,
that update introduced a regression that caused the kernel to freeze
when accessing CIFS shares in some situations. This update fixes
the problem.

We apologize for the inconvenience.

Original advisory details:

It was discovered that the Bluetooth subsystem 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 execute arbitrary
code. (CVE-2021-3640)

Likang Luo discovered that a race condition existed in the Bluetooth
subsystem of the Linux kernel, leading to a use-after-free vulnerability. A
local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2021-3752)

Luo Likang discovered that the FireDTV Firewire driver in the Linux kernel
did not properly perform bounds checking in some situations. A local
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2021-42739)

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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.

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Update instructions

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

Ubuntu 20.04
Ubuntu 18.04

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

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