Ubuntu 20.04 LTS & 18.04 LTS: USN-5210-2 Moderate Boot Kernel Issue

ubuntu

January 12, 2022

USN-5210-1 introduced a regression in the Linux kernel.

Summary

USN-5210-1 introduced a regression in the Linux kernel.

Software Description:

- linux: Linux kernel

- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems

- linux-gcp-5.4: Linux kernel for Google Cloud Platform (GCP) systems

- linux-hwe-5.4: Linux hardware enablement (HWE) kernel

Details:

USN-5210-1 fixed vulnerabilities in the Linux kernel. Unfortunately,

that update introduced a regression that caused failures to boot in

environments with AMD Secure Encrypted Virtualization (SEV) enabled.

This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Nadav Amit discovered that the hugetlb implementation in the Linux kernel

did not perform TLB flushes under certain conditions. A local attacker

could use this to leak or alter data from other processes that use huge

pages. (CVE-2021-4002)

It was discovered that the Linux kernel did not properly enforce certain

types of entries in the Secure Boot Forbidden Signature Database (aka...

Read the Full Advisory

Topics Covered

security advisory DoS ubuntu linux kernel regression boot failure SEV

Update Instructions

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

Ubuntu 20.04 LTS:
  linux-image-5.4.0-1060-gcp      5.4.0-1060.64
  linux-image-5.4.0-94-generic    5.4.0-94.106
  linux-image-5.4.0-94-generic-lpae  5.4.0-94.106
  linux-image-5.4.0-94-lowlatency  5.4.0-94.106
  linux-image-gcp-lts-20.04       5.4.0.1060.70
  linux-image-generic             5.4.0.94.98
  linux-image-generic-lpae        5.4.0.94.98
  linux-image-lowlatency          5.4.0.94.98
  linux-image-oem                 5.4.0.94.98
  linux-image-oem-osp1            5.4.0.94.98
  linux-image-virtual             5.4.0.94.98

Ubuntu 18.04 LTS:
  linux-image-5.4.0-1060-gcp      5.4.0-1060.64~18.04.1
  linux-image-5.4.0-94-generic    5.4.0-94.106~18.04.1
  linux-image-5.4.0-94-generic-lpae  5.4.0-94.106~18.04.1
  linux-image-5.4.0-94-lowlatency  5.4.0-94.106~18.04.1
  linux-image-gcp                 5.4.0.1060.46
  linux-image-generic-hwe-18.04   5.4.0.94.106~18.04.83
  linux-image-generic-lpae-hwe-18.04  5.4.0.94.106~18.04.83
  linux-image-lowlatency-hwe-18.04  5.4.0.94.106~18.04.83
  linux-image-oem                 5.4.0.94.106~18.04.83
  linux-image-oem-osp1            5.4.0.94.106~18.04.83
  linux-image-snapdragon-hwe-18.04  5.4.0.94.106~18.04.83
  linux-image-virtual-hwe-18.04   5.4.0.94.106~18.04.83

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.