=========================================================================
Ubuntu Security Notice USN-4577-1
October 14, 2020

linux-hwe, linux-gke-5.0, linux-gke-5.3, linux-oem-osp1, linux-raspi2-5.3
vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-gke-5.0: Linux kernel for Google Container Engine (GKE) systems
- linux-gke-5.3: Linux kernel for Google Container Engine (GKE) systems
- linux-hwe: Linux hardware enablement (HWE) kernel
- linux-oem-osp1: Linux kernel for OEM systems
- linux-raspi2-5.3: Linux kernel for Raspberry Pi (V8) systems

Details:

Hador Manor discovered that the DCCP protocol implementation in the Linux
kernel improperly handled socket reuse, leading to a use-after-free
vulnerability. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2020-16119)

Giuseppe Scrivano discovered that the overlay file system in the Linux
kernel did not properly perform permission checks in some situations. A
local attacker could possibly use this to bypass intended restrictions and
gain read access to restricted files. (CVE-2020-16120)

Update instructions:

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

Ubuntu 18.04 LTS:
  linux-image-5.0.0-1049-gke      5.0.0-1049.50
  linux-image-5.0.0-1069-oem-osp1  5.0.0-1069.75
  linux-image-5.3.0-1035-raspi2   5.3.0-1035.37
  linux-image-5.3.0-1038-gke      5.3.0-1038.40
  linux-image-5.3.0-68-generic    5.3.0-68.63
  linux-image-5.3.0-68-lowlatency  5.3.0-68.63
  linux-image-gke-5.0             5.0.0.1049.33
  linux-image-gke-5.3             5.3.0.1038.21
  linux-image-gkeop-5.3           5.3.0.68.125
  linux-image-oem-osp1            5.0.0.1069.67
  linux-image-raspi2-hwe-18.04    5.3.0.1035.24

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/4577-1
  CVE-2020-16119, CVE-2020-16120

Package Information:
  https://launchpad.net/ubuntu/+source/linux-gke-5.0/5.0.0-1049.50
  https://launchpad.net/ubuntu/+source/linux-gke-5.3/5.3.0-1038.40
  https://launchpad.net/ubuntu/+source/linux-hwe/5.3.0-68.63
  https://launchpad.net/ubuntu/+source/linux-oem-osp1/5.0.0-1069.75
  https://launchpad.net/ubuntu/+source/linux-raspi2-5.3/5.3.0-1035.37