Ubuntu 20.04: USN-4369-2 Severity Moderate: Linux Kernel Regression Fix

ubuntu

May 28, 2020

USN-4369-1 introduced a regression in the Linux kernel.

Summary

USN-4369-1 introduced a regression in the Linux kernel.

Software Description:

- linux: Linux kernel

- linux-raspi2: Linux kernel for Raspberry Pi (V7) systems

- linux-raspi2-5.3: Linux kernel for Raspberry Pi (V7) systems

Details:

USN-4369-1 fixed vulnerabilities in the 5.3 Linux kernel. Unfortunately,

that update introduced a regression in overlayfs. This update corrects

the problem.

We apologize for the inconvenience.

Original advisory details:

It was discovered that the btrfs implementation in the Linux kernel did not

properly detect that a block was marked dirty in some situations. An

attacker could use this to specially craft a file system image that, when

unmounted, could cause a denial of service (system crash). (CVE-2019-19377)

Tristan Madani discovered that the file locking implementation in the Linux

kernel contained a race condition. A local attacker could possibly use this

to cause a denial of service or expose sensitive information.

(CVE-2019-19769)

It...

Read the Full Advisory

Topics Covered

security advisory DoS issue software update security fix Ubuntu linux kernel regression

Update Instructions

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

Ubuntu 19.10:
  linux-image-5.3.0-1026-raspi2   5.3.0-1026.28
  linux-image-5.3.0-55-generic    5.3.0-55.49
  linux-image-5.3.0-55-generic-lpae  5.3.0-55.49
  linux-image-5.3.0-55-lowlatency  5.3.0-55.49
  linux-image-5.3.0-55-snapdragon  5.3.0-55.49
  linux-image-generic             5.3.0.55.47
  linux-image-generic-lpae        5.3.0.55.47
  linux-image-lowlatency          5.3.0.55.47
  linux-image-raspi2              5.3.0.1026.23
  linux-image-snapdragon          5.3.0.55.47
  linux-image-virtual             5.3.0.55.47

Ubuntu 18.04 LTS:
  linux-image-5.3.0-1026-raspi2   5.3.0-1026.28~18.04.1
  linux-image-raspi2-hwe-18.04    5.3.0.1026.15

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.