A Linux kernel security update has been released for Ubuntu Linux 19.10 and 18.04 LTS.

USN-4342-1: Linux kernel vulnerabilities

=========================================================================
Ubuntu Security Notice USN-4342-1
April 28, 2020

linux, linux-aws, linux-azure, linux-gcp, linux-gke-5.3, linux-hwe,
linux-kvm, linux-raspi2, linux-raspi2-5.3 vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 19.10
- Ubuntu 18.04 LTS

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: Linux kernel for Microsoft Azure Cloud systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-kvm: Linux kernel for cloud environments
- linux-raspi2: Linux kernel for Raspberry Pi 2
- linux-gke-5.3: Linux kernel for Google Container Engine (GKE) systems
- linux-hwe: Linux hardware enablement (HWE) kernel
- linux-raspi2-5.3: Linux kernel for Raspberry Pi 2

Details:

Al Viro discovered that the Linux kernel for s390x systems did not properly
perform page table upgrades for kernel sections that use secondary address
mode. A local attacker could use this to cause a denial of service (system
crash) or execute arbitrary code. (CVE-2020-11884)

It was discovered that the Intel Wi-Fi driver in the Linux kernel did not
properly check for errors in some situations. A local attacker could
possibly use this to cause a denial of service (system crash).
(CVE-2019-16234)

Tristan Madani discovered that the block I/O tracing implementation in the
Linux kernel contained a race condition. A local attacker could use this to
cause a denial of service (system crash) or possibly expose sensitive
information. (CVE-2019-19768)

It was discovered that the vhost net driver in the Linux kernel contained a
stack buffer overflow. A local attacker with the ability to perform ioctl()
calls on /dev/vhost-net could use this to cause a denial of service (system
crash). (CVE-2020-10942)

It was discovered that the virtual terminal implementation in the Linux
kernel contained a race condition. A local attacker could possibly use this
to cause a denial of service (system crash) or expose sensitive
information. (CVE-2020-8648)

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)

Jordy Zomer discovered that the floppy driver in the Linux kernel did not
properly check for errors in some situations. A local attacker could
possibly use this to cause a denial of service (system crash) or possibly
expose sensitive information. (CVE-2020-9383)

Update instructions:

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

Ubuntu 19.10:
linux-image-5.3.0-1016-kvm 5.3.0-1016.17
linux-image-5.3.0-1017-aws 5.3.0-1017.18
linux-image-5.3.0-1018-gcp 5.3.0-1018.19
linux-image-5.3.0-1020-azure 5.3.0-1020.21
linux-image-5.3.0-1023-raspi2 5.3.0-1023.25
linux-image-5.3.0-51-generic 5.3.0-51.44
linux-image-5.3.0-51-generic-lpae 5.3.0-51.44
linux-image-5.3.0-51-lowlatency 5.3.0-51.44
linux-image-5.3.0-51-snapdragon 5.3.0-51.44
linux-image-aws 5.3.0.1017.19
linux-image-azure 5.3.0.1020.39
linux-image-gcp 5.3.0.1018.19
linux-image-generic 5.3.0.51.42
linux-image-generic-lpae 5.3.0.51.42
linux-image-gke 5.3.0.1018.19
linux-image-kvm 5.3.0.1016.18
linux-image-lowlatency 5.3.0.51.42
linux-image-raspi2 5.3.0.1023.20
linux-image-snapdragon 5.3.0.51.42
linux-image-virtual 5.3.0.51.42

Ubuntu 18.04 LTS:
linux-image-5.3.0-1018-gke 5.3.0-1018.19~18.04.1
linux-image-5.3.0-1023-raspi2 5.3.0-1023.25~18.04.1
linux-image-5.3.0-51-generic 5.3.0-51.44~18.04.2
linux-image-5.3.0-51-generic-lpae 5.3.0-51.44~18.04.2
linux-image-5.3.0-51-lowlatency 5.3.0-51.44~18.04.2
linux-image-generic-hwe-18.04 5.3.0.51.104
linux-image-generic-lpae-hwe-18.04 5.3.0.51.104
linux-image-gke-5.3 5.3.0.1018.8
linux-image-lowlatency-hwe-18.04 5.3.0.51.104
linux-image-raspi2-hwe-18.04 5.3.0.1023.12
linux-image-snapdragon-hwe-18.04 5.3.0.51.104
linux-image-virtual-hwe-18.04 5.3.0.51.104

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/4342-1
CVE-2019-16234, CVE-2019-19768, CVE-2020-10942, CVE-2020-11884,
CVE-2020-8648, CVE-2020-8992, CVE-2020-9383

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.3.0-51.44
  https://launchpad.net/ubuntu/+source/linux-aws/5.3.0-1017.18
  https://launchpad.net/ubuntu/+source/linux-azure/5.3.0-1020.21
  https://launchpad.net/ubuntu/+source/linux-gcp/5.3.0-1018.19
  https://launchpad.net/ubuntu/+source/linux-kvm/5.3.0-1016.17
  https://launchpad.net/ubuntu/+source/linux-raspi2/5.3.0-1023.25
  https://launchpad.net/ubuntu/+source/linux-gke-5.3/5.3.0-1018.19~18.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe/5.3.0-51.44~18.04.2
  https://launchpad.net/ubuntu/+source/linux-raspi2-5.3/5.3.0-1023.25~18.04.1