USN-4878-1: Linux kernel vulnerabilities

16 March 2021

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-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-kvm - Linux kernel for cloud environments
  • linux-oracle - Linux kernel for Oracle Cloud systems
  • linux-oracle-5.4 - Linux kernel for Oracle Cloud systems
  • linux-raspi - Linux kernel for Raspberry Pi (V8) systems
  • linux-raspi-5.4 - Linux kernel for Raspberry Pi (V8) systems

Details

It was discovered that the Marvell WiFi-Ex device driver in the Linux
kernel did not properly validate ad-hoc SSIDs. A local attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2020-36158)

Ryota Shiga discovered that the sockopt BPF hooks in the Linux kernel could
allow a user space program to probe for valid kernel addresses. A local
attacker could use this to ease exploitation of another kernel
vulnerability. (CVE-2021-20239)

It was discovered that the priority inheritance futex implementation in the
Linux kernel contained a race condition, 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-2021-3347)

吴异 discovered that the NFS implementation in the Linux kernel did not
properly prevent access outside of an NFS export that is a subdirectory of
a file system. An attacker could possibly use this to bypass NFS access
restrictions. (CVE-2021-3178)

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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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