==========================================================================
Ubuntu Security Notice USN-5114-1
October 20, 2021

linux, linux-aws, linux-aws-hwe, linux-azure, linux-azure-4.15,
linux-dell300x, linux-gcp, linux-gcp-4.15, linux-hwe, linux-kvm,
linux-raspi2, linux-snapdragon vulnerabilities
==========================================================================

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

- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM

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-4.15: Linux kernel for Microsoft Azure Cloud systems
- linux-dell300x: Linux kernel for Dell 300x platforms
- linux-gcp-4.15: Linux kernel for Google Cloud Platform (GCP) systems
- linux-kvm: Linux kernel for cloud environments
- linux-raspi2: Linux kernel for Raspberry Pi systems
- linux-snapdragon: Linux kernel for Qualcomm Snapdragon processors
- linux-aws-hwe: Linux kernel for Amazon Web Services (AWS-HWE) systems
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-hwe: Linux hardware enablement (HWE) kernel

Details:

It was discovered that a race condition existed in the Atheros Ath9k WiFi
driver in the Linux kernel. An attacker could possibly use this to expose
sensitive information (WiFi network traffic). (CVE-2020-3702)

It was discovered that the KVM hypervisor implementation in the Linux
kernel did not properly compute the access permissions for shadow pages in
some situations. A local attacker could use this to cause a denial of
service. (CVE-2021-38198)

It was discovered that the ext4 file system in the Linux kernel contained a
race condition when writing xattrs to an inode. A local attacker could use
this to cause a denial of service or possibly gain administrative
privileges. (CVE-2021-40490)

It was discovered that the 6pack network protocol driver in the Linux
kernel did not properly perform validation checks. A privileged attacker
could use this to cause a denial of service (system crash) or execute
arbitrary code. (CVE-2021-42008)

Update instructions:

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

Ubuntu 18.04 LTS:
  linux-image-4.15.0-1029-dell300x  4.15.0-1029.34
  linux-image-4.15.0-1097-raspi2  4.15.0-1097.103
  linux-image-4.15.0-1101-kvm     4.15.0-1101.103
  linux-image-4.15.0-1110-gcp     4.15.0-1110.124
  linux-image-4.15.0-1114-aws     4.15.0-1114.121
  linux-image-4.15.0-1114-snapdragon  4.15.0-1114.123
  linux-image-4.15.0-1125-azure   4.15.0-1125.138
  linux-image-4.15.0-161-generic  4.15.0-161.169
  linux-image-4.15.0-161-generic-lpae  4.15.0-161.169
  linux-image-4.15.0-161-lowlatency  4.15.0-161.169
  linux-image-aws-lts-18.04       4.15.0.1114.117
  linux-image-azure-lts-18.04     4.15.0.1125.98
  linux-image-dell300x            4.15.0.1029.31
  linux-image-gcp-lts-18.04       4.15.0.1110.129
  linux-image-generic             4.15.0.161.150
  linux-image-generic-lpae        4.15.0.161.150
  linux-image-kvm                 4.15.0.1101.97
  linux-image-lowlatency          4.15.0.161.150
  linux-image-raspi2              4.15.0.1097.95
  linux-image-snapdragon          4.15.0.1114.117
  linux-image-virtual             4.15.0.161.150

Ubuntu 16.04 ESM:
  linux-image-4.15.0-1110-gcp     4.15.0-1110.124~16.04.1
  linux-image-4.15.0-1113-aws     4.15.0-1113.120~16.04.1
  linux-image-4.15.0-1125-azure   4.15.0-1125.138~16.04.1
  linux-image-4.15.0-161-generic  4.15.0-161.169~16.04.1
  linux-image-4.15.0-161-lowlatency  4.15.0-161.169~16.04.1
  linux-image-aws-hwe             4.15.0.1113.104
  linux-image-azure               4.15.0.1125.116
  linux-image-gcp                 4.15.0.1110.111
  linux-image-generic-hwe-16.04   4.15.0.161.154
  linux-image-gke                 4.15.0.1110.111
  linux-image-lowlatency-hwe-16.04  4.15.0.161.154
  linux-image-oem                 4.15.0.161.154
  linux-image-virtual-hwe-16.04   4.15.0.161.154

Ubuntu 14.04 ESM:
  linux-image-4.15.0-1125-azure   4.15.0-1125.138~14.04.1
  linux-image-azure               4.15.0.1125.98

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-5114-1
  CVE-2020-3702, CVE-2021-38198, CVE-2021-40490, CVE-2021-42008

Package Information:
  https://launchpad.net/ubuntu/+source/linux/4.15.0-161.169
  https://launchpad.net/ubuntu/+source/linux-aws/4.15.0-1114.121
  https://launchpad.net/ubuntu/+source/linux-azure-4.15/4.15.0-1125.138
  https://launchpad.net/ubuntu/+source/linux-dell300x/4.15.0-1029.34
  https://launchpad.net/ubuntu/+source/linux-gcp-4.15/4.15.0-1110.124
  https://launchpad.net/ubuntu/+source/linux-kvm/4.15.0-1101.103
  https://launchpad.net/ubuntu/+source/linux-raspi2/4.15.0-1097.103
  https://launchpad.net/ubuntu/+source/linux-snapdragon/4.15.0-1114.123