[USN-5086-1] Linux kernel vulnerability

[Steve Beattie]

==========================================================================
Ubuntu Security Notice USN-5086-1
September 22, 2021

linux, linux-hwe, linux-hwe-5.11, linux-hwe-5.4 vulnerability
==========================================================================

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

- Ubuntu 21.04
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM

Summary:

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

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

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

Ubuntu 21.04:
  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

Ubuntu 20.04 LTS:
  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

Ubuntu 18.04 LTS:
  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

Ubuntu 16.04 ESM:
  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

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://ubuntu.com/security/notices/USN-5086-1
  https://launchpad.net/bugs/1943960

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.11.0-36.40
  https://launchpad.net/ubuntu/+source/linux/5.4.0-86.97
  https://launchpad.net/ubuntu/+source/linux-hwe-5.11/5.11.0-36.40~20.04.1
  https://launchpad.net/ubuntu/+source/linux/4.15.0-158.166
  https://launchpad.net/ubuntu/+source/linux-hwe-5.4/5.4.0-86.97~18.04.1

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