Ubuntu 20.10: USN-4678-1 Critical: Kernel Information Exposure Threat

ubuntu

January 5, 2021

Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

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

Details:

It was discovered that the AMD Running Average Power Limit (RAPL) driver in

the Linux kernel did not properly restrict access to power data. A local

attacker could possibly use this to expose sensitive information.

(CVE-2020-12912)

Jann Horn discovered that the io_uring subsystem in the Linux kernel did

not properly perform reference counting in some situations. A local

attacker could use this to expose sensitive information or possibly

escalate privileges. (CVE-2020-29534)

Topics Covered

security advisory security issue critical privilege escalation kernel update instructions information exposure ubuntu sensitive data cloud

Update Instructions

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

Ubuntu 20.10:
  linux-image-5.8.0-1011-raspi    5.8.0-1011.14
  linux-image-5.8.0-1011-raspi-nolpae  5.8.0-1011.14
  linux-image-5.8.0-1014-kvm      5.8.0-1014.15
  linux-image-5.8.0-1014-oracle   5.8.0-1014.14
  linux-image-5.8.0-1015-gcp      5.8.0-1015.15
  linux-image-5.8.0-1016-azure    5.8.0-1016.17
  linux-image-5.8.0-1017-aws      5.8.0-1017.18
  linux-image-5.8.0-34-generic    5.8.0-34.37
  linux-image-5.8.0-34-generic-64k  5.8.0-34.37
  linux-image-5.8.0-34-generic-lpae  5.8.0-34.37
  linux-image-5.8.0-34-lowlatency  5.8.0-34.37
  linux-image-aws                 5.8.0.1017.19
  linux-image-azure               5.8.0.1016.16
  linux-image-gcp                 5.8.0.1015.15
  linux-image-generic             5.8.0.34.39
  linux-image-generic-64k         5.8.0.34.39
  linux-image-generic-lpae        5.8.0.34.39
  linux-image-gke                 5.8.0.1015.15
  linux-image-kvm                 5.8.0.1014.16
  linux-image-lowlatency          5.8.0.34.39
  linux-image-oracle              5.8.0.1014.14
  linux-image-raspi               5.8.0.1011.14
  linux-image-raspi-nolpae        5.8.0.1011.14
  linux-image-virtual             5.8.0.34.39

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.