A Linux kernel security update has been released for Ubuntu Linux 18.04 LTS, 16.04 LTS, and 14.04 ESM.

USN-4324-1: Linux kernel vulnerabilities

=========================================================================
Ubuntu Security Notice USN-4324-1
April 07, 2020

linux-aws, linux-aws-hwe, linux-azure, linux-gcp, linux-gke-4.15,
linux-kvm, linux-oem, linux-oracle, linux-raspi2, linux-snapdragon
vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

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

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-gke-4.15: Linux kernel for Google Container Engine (GKE) systems
- linux-kvm: Linux kernel for cloud environments
- linux-oem: Linux kernel for OEM processors
- linux-oracle: Linux kernel for Oracle Cloud systems
- linux-raspi2: Linux kernel for Raspberry Pi 2
- linux-snapdragon: Linux kernel for 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

Details:

Al Viro discovered that the vfs layer in the Linux kernel contained a use-
after-free vulnerability. A local attacker could use this to cause a denial
of service (system crash) or possibly expose sensitive information (kernel
memory). (CVE-2020-8428)

Shijie Luo discovered that the ext4 file system implementation in the Linux
kernel did not properly check for a too-large journal size. An attacker
could use this to construct a malicious ext4 image that, when mounted,
could cause a denial of service (soft lockup). (CVE-2020-8992)

Update instructions:

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

Ubuntu 18.04 LTS:
linux-image-4.15.0-1037-oracle 4.15.0-1037.41
linux-image-4.15.0-1057-gke 4.15.0-1057.60
linux-image-4.15.0-1058-kvm 4.15.0-1058.59
linux-image-4.15.0-1060-raspi2 4.15.0-1060.64
linux-image-4.15.0-1065-aws 4.15.0-1065.69
linux-image-4.15.0-1076-snapdragon 4.15.0-1076.83
linux-image-4.15.0-1079-oem 4.15.0-1079.89
linux-image-aws 4.15.0.1065.67
linux-image-aws-lts-18.04 4.15.0.1065.67
linux-image-gke 4.15.0.1057.61
linux-image-gke-4.15 4.15.0.1057.61
linux-image-kvm 4.15.0.1058.58
linux-image-oem 4.15.0.1079.83
linux-image-oracle-lts-18.04 4.15.0.1037.45
linux-image-raspi2 4.15.0.1060.58
linux-image-snapdragon 4.15.0.1076.79

Ubuntu 16.04 LTS:
linux-image-4.15.0-1037-oracle 4.15.0-1037.41~16.04.1
linux-image-4.15.0-1060-gcp 4.15.0-1060.64
linux-image-4.15.0-1065-aws 4.15.0-1065.69~16.04.1
linux-image-4.15.0-1077-azure 4.15.0-1077.82
linux-image-aws-hwe 4.15.0.1065.65
linux-image-azure 4.15.0.1077.80
linux-image-azure-edge 4.15.0.1077.80
linux-image-gcp 4.15.0.1060.74
linux-image-gke 4.15.0.1060.74
linux-image-oracle 4.15.0.1037.30

Ubuntu 14.04 ESM:
linux-image-4.15.0-1077-azure 4.15.0-1077.82~14.04.1
linux-image-azure 4.15.0.1077.62

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/4324-1
CVE-2020-8428, CVE-2020-8992

Package Information:
  https://launchpad.net/ubuntu/+source/linux-aws/4.15.0-1065.69
  https://launchpad.net/ubuntu/+source/linux-gke-4.15/4.15.0-1057.60
  https://launchpad.net/ubuntu/+source/linux-kvm/4.15.0-1058.59
  https://launchpad.net/ubuntu/+source/linux-oem/4.15.0-1079.89
  https://launchpad.net/ubuntu/+source/linux-oracle/4.15.0-1037.41
  https://launchpad.net/ubuntu/+source/linux-raspi2/4.15.0-1060.64
  https://launchpad.net/ubuntu/+source/linux-snapdragon/4.15.0-1076.83
  https://launchpad.net/ubuntu/+source/linux-aws-hwe/4.15.0-1065.69~16.04.1
  https://launchpad.net/ubuntu/+source/linux-azure/4.15.0-1077.82
  https://launchpad.net/ubuntu/+source/linux-gcp/4.15.0-1060.64
  https://launchpad.net/ubuntu/+source/linux-oracle/4.15.0-1037.41~16.04.1