==========================================================================
Ubuntu Security Notice USN-6441-2
October 23, 2023
linux-gcp-5.4 vulnerabilities
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.04 LTS (Available with Ubuntu Pro)
Summary:
Several security issues were fixed in the Linux kernel.
Software Description:
- linux-gcp-5.4: Linux kernel for Google Cloud Platform (GCP) 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)
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)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 18.04 LTS (Available with Ubuntu Pro):
   linux-image-5.4.0-1116-gcp      5.4.0-1116.125~18.04.1
   linux-image-gcp                 5.4.0.1116.92
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-6441-2
   https://ubuntu.com/security/notices/USN-6441-1
   CVE-2023-34319, CVE-2023-42752, CVE-2023-42753, CVE-2023-42755,
   CVE-2023-42756, CVE-2023-4622, CVE-2023-4623, CVE-2023-4881,
   CVE-2023-4921