A Linux kernel security update has been released for Ubuntu Linux 18.04 LTS, 20.04 LTS, and 20.10.

USN-4689-4: Linux kernel update

=========================================================================
Ubuntu Security Notice USN-4689-4
January 21, 2021

linux, linux-aws, linux-azure, linux-gcp, linux-hwe-5.4, linux-hwe-5.8,
linux-oracle update
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in NVIDIA graphics drivers.

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-oracle: Linux kernel for Oracle Cloud systems
- linux-hwe-5.8: Linux hardware enablement (HWE) kernel
- linux-hwe-5.4: Linux hardware enablement (HWE) kernel

Details:

USN-4689-3 fixed vulnerabilities in the NVIDIA server graphics drivers.
This update provides the corresponding updates for the NVIDIA Linux
DKMS kernel modules.

Original advisory details:

It was discovered that the NVIDIA GPU display driver for the Linux kernel
contained a vulnerability that allowed user-mode clients to access legacy
privileged APIs. A local attacker could use this to cause a denial of
service or escalate privileges. (CVE-2021-1052)

It was discovered that the NVIDIA GPU display driver for the Linux kernel
did not properly validate a pointer received from userspace in some
situations. A local attacker could use this to cause a denial of service.
(CVE-2021-1053)

Xinyuan Lyu discovered that the NVIDIA GPU display driver for the Linux
kernel did not properly restrict device-level GPU isolation. A local
attacker could use this to cause a denial of service or possibly expose
sensitive information. (CVE-2021-1056)

Update instructions:

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

Ubuntu 20.10:
linux-image-5.8.0-1017-oracle 5.8.0-1017.18
linux-image-5.8.0-1019-azure 5.8.0-1019.21
linux-image-5.8.0-1019-gcp 5.8.0-1019.20
linux-image-5.8.0-1020-aws 5.8.0-1020.22
linux-image-5.8.0-40-generic 5.8.0-40.45
linux-image-5.8.0-40-lowlatency 5.8.0-40.45
linux-image-aws 5.8.0.1020.22
linux-image-azure 5.8.0.1019.19
linux-image-gcp 5.8.0.1019.19
linux-image-generic 5.8.0.40.44
linux-image-gke 5.8.0.1019.19
linux-image-lowlatency 5.8.0.40.44
linux-image-oem-20.04 5.8.0.40.44
linux-image-oracle 5.8.0.1017.17
linux-image-virtual 5.8.0.40.44

Ubuntu 20.04 LTS:
linux-image-5.4.0-64-generic 5.4.0-64.72
linux-image-5.4.0-64-lowlatency 5.4.0-64.72
linux-image-5.8.0-40-generic 5.8.0-40.45~20.04.1
linux-image-5.8.0-40-lowlatency 5.8.0-40.45~20.04.1
linux-image-generic 5.4.0.64.67
linux-image-generic-hwe-20.04 5.8.0.40.45~20.04.25
linux-image-generic-lpae-hwe-20.04 5.8.0.40.45~20.04.25
linux-image-lowlatency 5.4.0.64.67
linux-image-lowlatency-hwe-20.04 5.8.0.40.45~20.04.25
linux-image-oem 5.4.0.64.67
linux-image-oem-osp1 5.4.0.64.67
linux-image-virtual 5.4.0.64.67
linux-image-virtual-hwe-20.04 5.8.0.40.45~20.04.25

Ubuntu 18.04 LTS:
linux-image-4.15.0-134-generic 4.15.0-134.138
linux-image-4.15.0-134-lowlatency 4.15.0-134.138
linux-image-5.4.0-64-generic 5.4.0-64.72~18.04.1
linux-image-5.4.0-64-lowlatency 5.4.0-64.72~18.04.1
linux-image-generic 4.15.0.134.121
linux-image-generic-hwe-18.04 5.4.0.64.72~18.04.59
linux-image-lowlatency 4.15.0.134.121
linux-image-lowlatency-hwe-18.04 5.4.0.64.72~18.04.59
linux-image-oem 5.4.0.64.72~18.04.59
linux-image-oem-osp1 5.4.0.64.72~18.04.59
linux-image-virtual 4.15.0.134.121
linux-image-virtual-hwe-18.04 5.4.0.64.72~18.04.59

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/4689-4
  https://usn.ubuntu.com/4689-1
CVE-2021-1052, CVE-2021-1053

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.8.0-40.45
  https://launchpad.net/ubuntu/+source/linux-aws/5.8.0-1020.22
  https://launchpad.net/ubuntu/+source/linux-azure/5.8.0-1019.21
  https://launchpad.net/ubuntu/+source/linux-gcp/5.8.0-1019.20
  https://launchpad.net/ubuntu/+source/linux-oracle/5.8.0-1017.18
  https://launchpad.net/ubuntu/+source/linux/5.4.0-64.72
  https://launchpad.net/ubuntu/+source/linux-hwe-5.8/5.8.0-40.45~20.04.1
  https://launchpad.net/ubuntu/+source/linux/4.15.0-134.138
  https://launchpad.net/ubuntu/+source/linux-hwe-5.4/5.4.0-64.72~18.04.1