[USN-4727-1] Linux kernel vulnerability

[Steve Beattie]

==========================================================================
Ubuntu Security Notice USN-4727-1
February 10, 2021

linux, linux-aws, linux-azure, linux-gcp, linux-hwe-5.8, linux-kvm,
linux-oem-5.6, linux-oracle, linux-raspi vulnerability
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.10
- Ubuntu 20.04 LTS

Summary:

The system could be made to crash or run programs as an administrator.

Software Description:
- linux: Linux kernel
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-kvm: Linux kernel for cloud environments
- linux-oracle: Linux kernel for Oracle Cloud systems
- linux-raspi: Linux kernel for Raspberry Pi (V8) systems
- linux-hwe-5.8: Linux hardware enablement (HWE) kernel
- linux-oem-5.6: Linux kernel for OEM systems

Details:

Alexander Popov discovered that multiple race conditions existed in the
AF_VSOCK implementation in the Linux kernel. A local attacker could use
this to cause a denial of service (system crash) or execute arbitrary code.

Update instructions:

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

Ubuntu 20.10:
  linux-image-5.8.0-1015-raspi    5.8.0-1015.18
  linux-image-5.8.0-1015-raspi-nolpae  5.8.0-1015.18
  linux-image-5.8.0-1018-kvm      5.8.0-1018.20
  linux-image-5.8.0-1020-oracle   5.8.0-1020.21
  linux-image-5.8.0-1022-azure    5.8.0-1022.24
  linux-image-5.8.0-1022-gcp      5.8.0-1022.23
  linux-image-5.8.0-1023-aws      5.8.0-1023.25
  linux-image-5.8.0-43-generic    5.8.0-43.49
  linux-image-5.8.0-43-generic-64k  5.8.0-43.49
  linux-image-5.8.0-43-generic-lpae  5.8.0-43.49
  linux-image-5.8.0-43-lowlatency  5.8.0-43.49
  linux-image-aws                 5.8.0.1023.25
  linux-image-azure               5.8.0.1022.22
  linux-image-gcp                 5.8.0.1022.22
  linux-image-generic             5.8.0.43.48
  linux-image-generic-64k         5.8.0.43.48
  linux-image-generic-lpae        5.8.0.43.48
  linux-image-gke                 5.8.0.1022.22
  linux-image-kvm                 5.8.0.1018.20
  linux-image-lowlatency          5.8.0.43.48
  linux-image-oracle              5.8.0.1020.19
  linux-image-raspi               5.8.0.1015.18
  linux-image-raspi-nolpae        5.8.0.1015.18
  linux-image-virtual             5.8.0.43.48

Ubuntu 20.04 LTS:
  linux-image-5.6.0-1047-oem      5.6.0-1047.51
  linux-image-5.8.0-43-generic    5.8.0-43.49~20.04.1
  linux-image-5.8.0-43-generic-lpae  5.8.0-43.49~20.04.1
  linux-image-5.8.0-43-lowlatency  5.8.0-43.49~20.04.1
  linux-image-generic-64k-hwe-20.04  5.8.0.43.49~20.04.29
  linux-image-generic-hwe-20.04   5.8.0.43.49~20.04.29
  linux-image-generic-lpae-hwe-20.04  5.8.0.43.49~20.04.29
  linux-image-lowlatency-hwe-20.04  5.8.0.43.49~20.04.29
  linux-image-oem-20.04           5.6.0.1047.43
  linux-image-virtual-hwe-20.04   5.8.0.43.49~20.04.29

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:
  https://usn.ubuntu.com/4727-1
  CVE-2021-26708

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.8.0-43.49
  https://launchpad.net/ubuntu/+source/linux-aws/5.8.0-1023.25
  https://launchpad.net/ubuntu/+source/linux-azure/5.8.0-1022.24
  https://launchpad.net/ubuntu/+source/linux-gcp/5.8.0-1022.23
  https://launchpad.net/ubuntu/+source/linux-kvm/5.8.0-1018.20
  https://launchpad.net/ubuntu/+source/linux-oracle/5.8.0-1020.21
  https://launchpad.net/ubuntu/+source/linux-raspi/5.8.0-1015.18
  https://launchpad.net/ubuntu/+source/linux-hwe-5.8/5.8.0-43.49~20.04.1
  https://launchpad.net/ubuntu/+source/linux-oem-5.6/5.6.0-1047.51

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