[USN-6205-1] Linux kernel (GKE) vulnerabilities

[Rodrigo Figueiredo Zaiden]

==========================================================================
Ubuntu Security Notice USN-6205-1
July 06, 2023

linux-gke vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-gke: Linux kernel for Google Container Engine (GKE) systems

Details:

Hangyu Hua discovered that the Flower classifier implementation in the
Linux kernel contained an out-of-bounds write vulnerability. An attacker
could use this to cause a denial of service (system crash) or possibly
execute arbitrary code. (CVE-2023-35788, LP: #2023577)

It was discovered that for some Intel processors the INVLPG instruction
implementation did not properly flush global TLB entries when PCIDs are
enabled. An attacker could use this to expose sensitive information
(kernel memory) or possibly cause undesired behaviors. (LP: #2023220)

Update instructions:

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

Ubuntu 20.04 LTS:
   linux-image-5.4.0-1103-gke      5.4.0-1103.110
   linux-image-gke                 5.4.0.1103.108
   linux-image-gke-5.4             5.4.0.1103.108

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-6205-1
   https://launchpad.net/bugs/2023220
   https://launchpad.net/bugs/2023577
   CVE-2023-35788

Package Information:
   https://launchpad.net/ubuntu/+source/linux-gke/5.4.0-1103.110

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