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Ubuntu 21.04: USN-5092-3 Moderate: Azure Kernel Boot Regression

ubuntu
Calendar Grey October 18, 2021
Dist Ubuntu Esm H88
USN-5092-3 addresses a bug in the Linux kernel affecting Azure cloud environments following earlier patches.
USN-5092-2 introduced a regression in the Linux kernel for Microsoft Azure cloud systems.

Summary

USN-5092-2 introduced a regression in the Linux kernel for Microsoft

Azure cloud systems.

Software Description:

- linux-azure: Linux kernel for Microsoft Azure Cloud systems

- linux-azure-5.11: Linux kernel for Microsoft Azure cloud systems

Details:

USN-5092-2 fixed vulnerabilities in Linux 5.11-based kernels.

Unfortunately, for Linux kernels intended for use within Microsoft

Azure environments, that update introduced a regression that could

cause the kernel to fail to boot in large Azure instance types.

This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Valentina Palmiotti discovered that the io_uring subsystem in the Linux

kernel could be coerced to free adjacent memory. A local attacker could use

this to execute arbitrary code. (CVE-2021-41073)

Ofek Kirzner, Adam Morrison, Benedict Schlueter, and Piotr Krysiuk

discovered that the BPF verifier in the Linux kernel missed possible

mispredicted branches due to type confusion, allowin...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory software fix system update ubuntu linux kernel regression issue azure cloud

Update Instructions

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

Ubuntu 21.04:
  linux-image-5.11.0-1019-azure   5.11.0-1019.20
  linux-image-azure               5.11.0.1019.20

Ubuntu 20.04 LTS:
  linux-image-5.11.0-1019-azure   5.11.0-1019.20~20.04.1
  linux-image-azure-edge          5.11.0.1019.20~20.04.18

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.

References

https://ubuntu.com/security/notices/USN-5092-3

https://ubuntu.com/security/notices/USN-5092-1

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1940564, https://ubuntu.com/security/notices/USN-5092-2

October 18, 2021

Topics%20covered

Topics Covered

security advisory software fix system update ubuntu linux kernel regression issue azure cloud

Package Information

https://launchpad.net/ubuntu/+source/linux-azure/5.11.0-1019.20
https://launchpad.net/ubuntu/+source/linux-azure-5.11/5.11.0-1019.20~20.04.1

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