==========================================================================
Ubuntu Security Notice USN-6342-1
September 06, 2023

linux, linux-aws, linux-aws-hwe, linux-gcp, linux-gcp-4.15, linux-hwe,
linux-kvm, linux-oracle vulnerabilities
==========================================================================

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

- Ubuntu 18.04 LTS (Available with Ubuntu Pro)
- Ubuntu 16.04 LTS (Available with Ubuntu Pro)

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-gcp-4.15: Linux kernel for Google Cloud Platform (GCP) systems
- linux-kvm: Linux kernel for cloud environments
- linux-aws-hwe: Linux kernel for Amazon Web Services (AWS-HWE) systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-hwe: Linux hardware enablement (HWE) kernel
- linux-oracle: Linux kernel for Oracle Cloud systems

Details:

Tavis Ormandy discovered that some AMD processors did not properly handle
speculative execution of certain vector register instructions. A local
attacker could use this to expose sensitive information. (CVE-2023-20593)

Zheng Zhang discovered that the device-mapper implementation in the Linux
kernel did not properly handle locking during table_clear() operations. A
local attacker could use this to cause a denial of service (kernel
deadlock). (CVE-2023-2269)

It was discovered that a use-after-free vulnerability existed in the HFS+
file system implementation in the Linux kernel. A local attacker could
possibly use this to cause a denial of service (system crash).
(CVE-2023-2985)

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)

It was discovered that the Quick Fair Queueing network scheduler
implementation in the Linux kernel contained 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-2023-3611)

It was discovered that the network packet classifier with
netfilter/firewall marks implementation in the Linux kernel did not
properly handle reference counting, 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-2023-3776)

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-4.15.0-1144-kvm     4.15.0-1144.149
   linux-image-4.15.0-1154-gcp     4.15.0-1154.171
   linux-image-4.15.0-1160-aws     4.15.0-1160.173
   linux-image-4.15.0-216-generic  4.15.0-216.227
   linux-image-4.15.0-216-lowlatency  4.15.0-216.227
   linux-image-aws-lts-18.04       4.15.0.1160.158
   linux-image-gcp-lts-18.04       4.15.0.1154.168
   linux-image-generic             4.15.0.216.200
   linux-image-kvm                 4.15.0.1144.135
   linux-image-lowlatency          4.15.0.216.200
   linux-image-virtual             4.15.0.216.200

Ubuntu 16.04 LTS (Available with Ubuntu Pro):
   linux-image-4.15.0-1123-oracle  4.15.0-1123.134~16.04.1
   linux-image-4.15.0-1154-gcp     4.15.0-1154.171~16.04.1
   linux-image-4.15.0-1160-aws     4.15.0-1160.173~16.04.1
   linux-image-4.15.0-216-generic  4.15.0-216.227~16.04.1
   linux-image-4.15.0-216-lowlatency  4.15.0-216.227~16.04.1
   linux-image-aws-hwe             4.15.0.1160.143
   linux-image-gcp                 4.15.0.1154.144
   linux-image-generic-hwe-16.04   4.15.0.216.200~16.04.1
   linux-image-gke                 4.15.0.1154.144
   linux-image-lowlatency-hwe-16.04  4.15.0.216.200~16.04.1
   linux-image-oem                 4.15.0.216.200~16.04.1
   linux-image-oracle              4.15.0.1123.104
   linux-image-virtual-hwe-16.04   4.15.0.216.200~16.04.1

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-6342-1
   CVE-2023-20593, CVE-2023-2269, CVE-2023-2985, CVE-2023-31084,
   CVE-2023-3611, CVE-2023-3776