Ubuntu Security Notices
USN-5086-1

USN-5086-1: Linux kernel vulnerability

Publication date

22 September 2021

Overview

IBM s390x systems could be made to crash or run programs as an administrator.

Releases

21.04 20.04 LTS 18.04 LTS 16.04 LTS

Packages

linux - Linux kernel
linux-hwe - Linux hardware enablement (HWE) kernel
linux-hwe-5.11 - Linux hardware enablement (HWE) kernel
linux-hwe-5.4 - Linux hardware enablement (HWE) kernel

Details

Johan Almbladh discovered that the eBPF JIT implementation for IBM
s390x systems in the Linux kernel miscompiled operations in some
situations, allowing circumvention of the BPF verifier. A local
attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code.

Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

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.

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

Ubuntu Release	Package Version
21.04 hirsute	linux-image-5.11.0-36-generic – 5.11.0-36.40
	linux-image-5.11.0-36-generic-64k – 5.11.0-36.40
	linux-image-5.11.0-36-generic-lpae – 5.11.0-36.40
	linux-image-5.11.0-36-lowlatency – 5.11.0-36.40
	linux-image-generic – 5.11.0.36.38
	linux-image-generic-64k – 5.11.0.36.38
	linux-image-generic-lpae – 5.11.0.36.38
	linux-image-lowlatency – 5.11.0.36.38
	linux-image-oem-20.04 – 5.11.0.36.38
	linux-image-virtual – 5.11.0.36.38
20.04 focal	linux-image-5.11.0-36-generic – 5.11.0-36.40~20.04.1
	linux-image-5.11.0-36-generic-64k – 5.11.0-36.40~20.04.1
	linux-image-5.11.0-36-generic-lpae – 5.11.0-36.40~20.04.1
	linux-image-5.11.0-36-lowlatency – 5.11.0-36.40~20.04.1
	linux-image-5.4.0-86-generic – 5.4.0-86.97
	linux-image-5.4.0-86-generic-lpae – 5.4.0-86.97
	linux-image-5.4.0-86-lowlatency – 5.4.0-86.97
	linux-image-generic – 5.4.0.86.90
	linux-image-generic-64k-hwe-20.04 – 5.11.0.36.40~20.04.15
	linux-image-generic-hwe-20.04 – 5.11.0.36.40~20.04.15
	linux-image-generic-lpae – 5.4.0.86.90
	linux-image-generic-lpae-hwe-20.04 – 5.11.0.36.40~20.04.15
	linux-image-lowlatency – 5.4.0.86.90
	linux-image-lowlatency-hwe-20.04 – 5.11.0.36.40~20.04.15
	linux-image-oem – 5.4.0.86.90
	linux-image-oem-osp1 – 5.4.0.86.90
	linux-image-virtual – 5.4.0.86.90
	linux-image-virtual-hwe-20.04 – 5.11.0.36.40~20.04.15
18.04 bionic	linux-image-4.15.0-158-generic – 4.15.0-158.166
	linux-image-4.15.0-158-generic-lpae – 4.15.0-158.166
	linux-image-4.15.0-158-lowlatency – 4.15.0-158.166
	linux-image-5.4.0-86-generic – 5.4.0-86.97~18.04.1
	linux-image-5.4.0-86-generic-lpae – 5.4.0-86.97~18.04.1
	linux-image-5.4.0-86-lowlatency – 5.4.0-86.97~18.04.1
	linux-image-generic – 4.15.0.158.147
	linux-image-generic-hwe-18.04 – 5.4.0.86.97~18.04.77
	linux-image-generic-lpae – 4.15.0.158.147
	linux-image-generic-lpae-hwe-18.04 – 5.4.0.86.97~18.04.77
	linux-image-lowlatency – 4.15.0.158.147
	linux-image-lowlatency-hwe-18.04 – 5.4.0.86.97~18.04.77
	linux-image-oem – 5.4.0.86.97~18.04.77
	linux-image-oem-osp1 – 5.4.0.86.97~18.04.77
	linux-image-snapdragon-hwe-18.04 – 5.4.0.86.97~18.04.77
	linux-image-virtual – 4.15.0.158.147
	linux-image-virtual-hwe-18.04 – 5.4.0.86.97~18.04.77
16.04 xenial	linux-image-4.15.0-158-generic – 4.15.0-158.166~16.04.1
	linux-image-4.15.0-158-lowlatency – 4.15.0-158.166~16.04.1
	linux-image-4.4.0-216-generic – 4.4.0-216.249
	linux-image-4.4.0-216-lowlatency – 4.4.0-216.249
	linux-image-generic – 4.4.0.216.223
	linux-image-generic-hwe-16.04 – 4.15.0.158.151
	linux-image-lowlatency – 4.4.0.216.223
	linux-image-lowlatency-hwe-16.04 – 4.15.0.158.151
	linux-image-oem – 4.15.0.158.151
	linux-image-virtual – 4.4.0.216.223
	linux-image-virtual-hwe-16.04 – 4.15.0.158.151

Reduce your security exposure

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.

Get Ubuntu Pro

References

https://launchpad.net/bugs/1943960

Have additional questions?

Talk to a member of the team ›