Ubuntu 21.04: USN-4950-1 Critical: Kernel Denial Of Service

ubuntu

May 11, 2021

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-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-oracle: Linux kernel for Oracle Cloud systems

- linux-raspi: Linux kernel for Raspberry Pi (V8) systems

Details:

Ryota Shiga discovered that the eBPF implementation in the Linux kernel did

not properly verify that a BPF program only reserved as much memory for a

ring buffer as was allocated. A local attacker could use this to cause a

denial of service (system crash) or execute arbitrary code. (CVE-2021-3489)

Manfred Paul discovered that the eBPF implementation in the Linux kernel

did not properly track bounds on bitwise operations. A local attacker could

use this to cause a denial of service (system crash) or execute arbitrary

code. (C...

Read the Full Advisory

Topics Covered

security advisory denial of service kernel update critical risk Ubuntu kernel update instructions ubuntu system crash Linux

Update Instructions

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

Ubuntu 21.04:
  linux-image-5.11.0-1005-azure   5.11.0-1005.5
  linux-image-5.11.0-1006-oracle  5.11.0-1006.6
  linux-image-5.11.0-1007-aws     5.11.0-1007.7
  linux-image-5.11.0-1007-gcp     5.11.0-1007.7
  linux-image-5.11.0-1007-kvm     5.11.0-1007.7
  linux-image-5.11.0-1008-raspi   5.11.0-1008.8
  linux-image-5.11.0-1008-raspi-nolpae  5.11.0-1008.8
  linux-image-5.11.0-17-generic   5.11.0-17.18
  linux-image-5.11.0-17-generic-64k  5.11.0-17.18
  linux-image-5.11.0-17-generic-lpae  5.11.0-17.18
  linux-image-5.11.0-17-lowlatency  5.11.0-17.18
  linux-image-aws                 5.11.0.1007.7
  linux-image-azure               5.11.0.1005.5
  linux-image-gcp                 5.11.0.1007.7
  linux-image-generic             5.11.0.17.18
  linux-image-generic-64k         5.11.0.17.18
  linux-image-generic-lpae        5.11.0.17.18
  linux-image-gke                 5.11.0.1007.7
  linux-image-kvm                 5.11.0.1007.7
  linux-image-lowlatency          5.11.0.17.18
  linux-image-oracle              5.11.0.1006.6
  linux-image-raspi               5.11.0.1008.6
  linux-image-raspi-nolpae        5.11.0.1008.6
  linux-image-virtual             5.11.0.17.18

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.