Ubuntu 20.04 LTS: USN-4367-1 Critical: Linux Kernel Denial Of Service

ubuntu

May 19, 2020

Several security issues were fixed in the Linux kernel.

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-gcp: Linux kernel for Google Cloud Platform (GCP) systems

- linux-kvm: Linux kernel for cloud environments

- linux-oracle: Linux kernel for Oracle Cloud systems

- linux-riscv: Linux kernel for RISC-V systems

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)

It was discovered that the linux kernel did not properly validate certain

mount options to the tmpfs virtual memory file system. A local attacker

with the ability to specify mount options could use this to cause a denial

of service (system crash). (CVE-2020-11565)

It was discovered that the block layer in ...

Read the Full Advisory

Topics Covered

security advisory denial of service kernel ubuntu system crash

Update Instructions

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

Ubuntu 20.04 LTS:
  linux-image-5.4.0-1011-aws      5.4.0-1011.11
  linux-image-5.4.0-1011-gcp      5.4.0-1011.11
  linux-image-5.4.0-1011-kvm      5.4.0-1011.11
  linux-image-5.4.0-1011-oracle   5.4.0-1011.11
  linux-image-5.4.0-26-generic    5.4.0-26.30
  linux-image-5.4.0-31-generic    5.4.0-31.35
  linux-image-5.4.0-31-generic-lpae  5.4.0-31.35
  linux-image-5.4.0-31-lowlatency  5.4.0-31.35
  linux-image-aws                 5.4.0.1011.14
  linux-image-gcp                 5.4.0.1011.12
  linux-image-generic             5.4.0.26.33
  linux-image-generic-lpae        5.4.0.31.36
  linux-image-gke                 5.4.0.1011.12
  linux-image-kvm                 5.4.0.1011.12
  linux-image-lowlatency          5.4.0.31.36
  linux-image-oem                 5.4.0.31.36
  linux-image-oem-osp1            5.4.0.31.36
  linux-image-oracle              5.4.0.1011.12
  linux-image-virtual             5.4.0.26.33

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.