==========================================================================
Ubuntu Security Notice USN-6339-2
September 08, 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:

It was discovered that the NTFS file system implementation in the Linux
kernel did not properly validate MFT flags in certain situations. An
attacker could use this to construct a malicious NTFS image that, when
mounted and operated on, could cause a denial of service (system crash).
(CVE-2022-48425)

Zi Fan Tan discovered that the binder IPC implementation in the Linux
kernel contained 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-2023-21255)

It was discovered that a race condition existed in the f2fs file system in
the Linux kernel, leading to a null pointer dereference vulnerability. An
attacker could use this to construct a malicious f2fs image that, when
mounted and operated on, could cause a denial of service (system crash).
(CVE-2023-2898)

It was discovered that the DVB Core driver in the Linux kernel did not
properly handle locking events in certain situations. A local attacker
could use this to cause a denial of service (kernel deadlock).
(CVE-2023-31084)

Yang Lan discovered that the GFS2 file system implementation in the Linux
kernel could attempt to dereference a null pointer in some situations. An
attacker could use this to construct a malicious GFS2 image that, when
mounted and operated on, could cause a denial of service (system crash).
(CVE-2023-3212)

It was discovered that the KSMBD implementation in the Linux kernel did not
properly validate buffer sizes in certain operations, leading to an out-of-
bounds read vulnerability. A remote attacker could use this to cause a
denial of service (system crash) or possibly expose sensitive information.
(CVE-2023-38426, CVE-2023-38428)

It was discovered that the KSMBD implementation in the Linux kernel did not
properly calculate the size of certain buffers. A remote attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2023-38429)

Update instructions:

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

Ubuntu 20.04 LTS:
  linux-image-5.15.0-1027-gkeop   5.15.0-1027.32~20.04.1
  linux-image-5.15.0-1041-gcp     5.15.0-1041.49~20.04.1
  linux-image-gcp                 5.15.0.1041.49~20.04.1
  linux-image-gkeop-5.15          5.15.0.1027.32~20.04.23

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-6339-2
  https://ubuntu.com/security/notices/USN-6339-1
  CVE-2022-48425, CVE-2023-21255, CVE-2023-2898, CVE-2023-31084,
  CVE-2023-3212, CVE-2023-38426, CVE-2023-38428, CVE-2023-38429

Package Information:
  https://launchpad.net/ubuntu/+source/linux-gcp-5.15/5.15.0-1041.49~20.04.1
  https://launchpad.net/ubuntu/+source/linux-gkeop-5.15/5.15.0-1027.32~20.04.1