[USN-6605-2] Linux kernel (KVM) vulnerabilities

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==========================================================================
Ubuntu Security Notice USN-6605-2
January 29, 2024

linux-kvm 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-kvm: Linux kernel for cloud environments

Details:

Lin Ma discovered that the netfilter subsystem in the Linux kernel did not
properly validate network family support while creating a new netfilter
table. A local attacker could use this to cause a denial of service or
possibly execute arbitrary code. (CVE-2023-6040)

It was discovered that the CIFS network file system implementation in the
Linux kernel did not properly validate the server frame size in certain
situation, leading to an out-of-bounds read vulnerability. An attacker
could use this to construct a malicious CIFS image that, when operated on,
could cause a denial of service (system crash) or possibly expose sensitive
information. (CVE-2023-6606)

Budimir Markovic, Lucas De Marchi, and Pengfei Xu discovered that the perf
subsystem in the Linux kernel did not properly validate all event sizes
when attaching new events, leading to an out-of-bounds write vulnerability.
A local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2023-6931)

It was discovered that the IGMP protocol implementation in the Linux kernel
contained a race condition, leading to a use-after-free vulnerability. A
local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2023-6932)

Update instructions:

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

Ubuntu 20.04 LTS:
linux-image-5.4.0-1105-kvm 5.4.0-1105.112
linux-image-kvm 5.4.0.1105.101

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-6605-2
https://ubuntu.com/security/notices/USN-6605-1
CVE-2023-6040, CVE-2023-6606, CVE-2023-6931, CVE-2023-6932

Package Information:
https://launchpad.net/ubuntu/+source/linux-kvm/5.4.0-1105.112