==========================================================================
Ubuntu Security Notice USN-6446-2
October 24, 2023

linux-gcp-5.15, linux-gkeop-5.15 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-gcp-5.15: Linux kernel for Google Cloud Platform (GCP) systems
- linux-gkeop-5.15: Linux kernel for Google Container Engine (GKE) systems

Details:

Ross Lagerwall discovered that the Xen netback backend driver in the Linux
kernel did not properly handle certain unusual packets from a
paravirtualized network frontend, leading to a buffer overflow. An attacker
in a guest VM could use this to cause a denial of service (host system
crash) or possibly execute arbitrary code. (CVE-2023-34319)

Bien Pham discovered that the netfiler subsystem in the Linux kernel
contained a race condition, leading to a use-after-free vulnerability. A
local user could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2023-4244)

Kyle Zeng discovered that the networking stack implementation in the Linux
kernel did not properly validate skb object size in certain conditions. An
attacker could use this cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2023-42752)

Kyle Zeng discovered that the netfiler subsystem in the Linux kernel did
not properly calculate array offsets, leading to a out-of-bounds write
vulnerability. A local user could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2023-42753)

Kyle Zeng discovered that the IPv4 Resource Reservation Protocol (RSVP)
classifier implementation in the Linux kernel contained an out-of-bounds
read vulnerability. A local attacker could use this to cause a denial of
service (system crash). Please note that kernel packet classifier support
for RSVP has been removed to resolve this vulnerability. (CVE-2023-42755)

Kyle Zeng discovered that the netfilter subsystem in the Linux kernel
contained a race condition in IP set operations in certain situations. A
local attacker could use this to cause a denial of service (system crash).
(CVE-2023-42756)

Bing-Jhong Billy Jheng discovered that the Unix domain socket
implementation in the Linux kernel contained a race condition in certain
situations, 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-2023-4622)

Budimir Markovic discovered that the qdisc implementation in the Linux
kernel did not properly validate inner classes, leading to a use-after-free
vulnerability. A local user could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2023-4623)

Alex Birnberg discovered that the netfilter subsystem in the Linux kernel
did not properly validate register length, leading to an out-of- bounds
write vulnerability. A local attacker could possibly use this to cause a
denial of service (system crash). (CVE-2023-4881)

It was discovered that the Quick Fair Queueing scheduler implementation in
the Linux kernel did not properly handle network packets in certain
conditions, 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-2023-4921)

Kevin Rich discovered that the netfilter subsystem in the Linux kernel did
not properly handle removal of rules from chain bindings in certain
circumstances, leading to a use-after-free vulnerability. A local attacker
could possibly use this to cause a denial of service (system crash) or
execute arbitrary code. (CVE-2023-5197)

Update instructions:

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

Ubuntu 20.04 LTS:
   linux-image-5.15.0-1031-gkeop   5.15.0-1031.37~20.04.1
   linux-image-5.15.0-1045-gcp     5.15.0-1045.53~20.04.2
   linux-image-gcp                 5.15.0.1045.53~20.04.1
   linux-image-gkeop-5.15          5.15.0.1031.37~20.04.27

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-6446-2
   https://ubuntu.com/security/notices/USN-6446-1
   CVE-2023-34319, CVE-2023-4244, CVE-2023-42752, CVE-2023-42753,
   CVE-2023-42755, CVE-2023-42756, CVE-2023-4622, CVE-2023-4623,
   CVE-2023-4881, CVE-2023-4921, CVE-2023-5197

Package Information:
   https://launchpad.net/ubuntu/+source/linux-gcp-5.15/5.15.0-1045.53~20.04.2
   https://launchpad.net/ubuntu/+source/linux-gkeop-5.15/5.15.0-1031.37~20.04.1