A Linux kernel security update has been released for Ubuntu Linux 18.04 LTS and 20.04 LTS.

[USN-6417-1] Linux kernel vulnerabilities

==========================================================================
Ubuntu Security Notice USN-6417-1
October 04, 2023

linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4,
linux-bluefield, linux-gcp, linux-gcp-5.4, linux-gkeop, linux-hwe-5.4,
linux-ibm, linux-ibm-5.4, linux-iot, linux-kvm, linux-oracle,
linux-oracle-5.4, linux-raspi, linux-raspi-5.4, linux-xilinx-zynqmp
vulnerabilities
==========================================================================

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

- Ubuntu 20.04 LTS
- Ubuntu 18.04 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-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-bluefield: Linux kernel for NVIDIA BlueField platforms
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-gkeop: Linux kernel for Google Container Engine (GKE) systems
- linux-ibm: Linux kernel for IBM cloud systems
- linux-iot: Linux kernel for IoT platforms
- linux-kvm: Linux kernel for cloud environments
- linux-oracle: Linux kernel for Oracle Cloud systems
- linux-raspi: Linux kernel for Raspberry Pi systems
- linux-xilinx-zynqmp: Linux kernel for Xilinx ZynqMP processors
- linux-aws-5.4: Linux kernel for Amazon Web Services (AWS) systems
- linux-azure-5.4: Linux kernel for Microsoft Azure cloud systems
- linux-gcp-5.4: Linux kernel for Google Cloud Platform (GCP) systems
- linux-hwe-5.4: Linux hardware enablement (HWE) kernel
- linux-ibm-5.4: Linux kernel for IBM cloud systems
- linux-oracle-5.4: Linux kernel for Oracle Cloud systems
- linux-raspi-5.4: Linux kernel for Raspberry Pi systems

Details:

It was discovered that the eBPF implementation in the Linux kernel
contained a race condition around read-only maps. A privileged attacker
could use this to modify read-only maps. (CVE-2021-4001)

It was discovered that the IPv6 implementation in the Linux kernel
contained a high rate of hash collisions in connection lookup table. A
remote attacker could use this to cause a denial of service (excessive CPU
consumption). (CVE-2023-1206)

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)

Davide Ornaghi discovered that the DECnet network protocol implementation
in the Linux kernel contained a null pointer dereference vulnerability. A
remote attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. Please note that kernel support for the
DECnet has been removed to resolve this CVE. (CVE-2023-3338)

It was discovered that the NFC implementation in the Linux kernel contained
a use-after-free vulnerability when performing peer-to-peer communication
in certain conditions. A privileged attacker could use this to cause a
denial of service (system crash) or possibly expose sensitive information
(kernel memory). (CVE-2023-3863)

It was discovered that the TUN/TAP driver in the Linux kernel did not
properly initialize socket data. A local attacker could use this to cause a
denial of service (system crash). (CVE-2023-4194)

Update instructions:

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

Ubuntu 20.04 LTS:
linux-image-5.4.0-1023-iot 5.4.0-1023.24
linux-image-5.4.0-1031-xilinx-zynqmp 5.4.0-1031.35
linux-image-5.4.0-1058-ibm 5.4.0-1058.63
linux-image-5.4.0-1072-bluefield 5.4.0-1072.78
linux-image-5.4.0-1078-gkeop 5.4.0-1078.82
linux-image-5.4.0-1095-raspi 5.4.0-1095.106
linux-image-5.4.0-1100-kvm 5.4.0-1100.106
linux-image-5.4.0-1110-oracle 5.4.0-1110.119
linux-image-5.4.0-1111-aws 5.4.0-1111.120
linux-image-5.4.0-1115-gcp 5.4.0-1115.124
linux-image-5.4.0-1117-azure 5.4.0-1117.124
linux-image-5.4.0-164-generic 5.4.0-164.181
linux-image-5.4.0-164-generic-lpae 5.4.0-164.181
linux-image-5.4.0-164-lowlatency 5.4.0-164.181
linux-image-aws-lts-20.04 5.4.0.1111.108
linux-image-azure-lts-20.04 5.4.0.1117.110
linux-image-bluefield 5.4.0.1072.67
linux-image-gcp-lts-20.04 5.4.0.1115.117
linux-image-generic 5.4.0.164.161
linux-image-generic-lpae 5.4.0.164.161
linux-image-gkeop 5.4.0.1078.76
linux-image-gkeop-5.4 5.4.0.1078.76
linux-image-ibm-lts-20.04 5.4.0.1058.87
linux-image-kvm 5.4.0.1100.95
linux-image-lowlatency 5.4.0.164.161
linux-image-oem 5.4.0.164.161
linux-image-oem-osp1 5.4.0.164.161
linux-image-oracle-lts-20.04 5.4.0.1110.103
linux-image-raspi 5.4.0.1095.125
linux-image-raspi2 5.4.0.1095.125
linux-image-virtual 5.4.0.164.161
linux-image-xilinx-zynqmp 5.4.0.1031.32

Ubuntu 18.04 LTS (Available with Ubuntu Pro):
linux-image-5.4.0-1058-ibm 5.4.0-1058.63~18.04.1
linux-image-5.4.0-1095-raspi 5.4.0-1095.106~18.04.1
linux-image-5.4.0-1110-oracle 5.4.0-1110.119~18.04.1
linux-image-5.4.0-1111-aws 5.4.0-1111.120~18.04.1
linux-image-5.4.0-1115-gcp 5.4.0-1115.124~18.04.1
linux-image-5.4.0-1117-azure 5.4.0-1117.124~18.04.1
linux-image-5.4.0-164-generic 5.4.0-164.181~18.04.1
linux-image-5.4.0-164-lowlatency 5.4.0-164.181~18.04.1
linux-image-aws 5.4.0.1111.89
linux-image-azure 5.4.0.1117.90
linux-image-gcp 5.4.0.1115.91
linux-image-generic-hwe-18.04 5.4.0.164.181~18.04.131
linux-image-ibm 5.4.0.1058.69
linux-image-lowlatency-hwe-18.04 5.4.0.164.181~18.04.131
linux-image-oem 5.4.0.164.181~18.04.131
linux-image-oem-osp1 5.4.0.164.181~18.04.131
linux-image-oracle 5.4.0.1110.119~18.04.82
linux-image-raspi-hwe-18.04 5.4.0.1095.92
linux-image-snapdragon-hwe-18.04 5.4.0.164.181~18.04.131
linux-image-virtual-hwe-18.04 5.4.0.164.181~18.04.131

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-6417-1
CVE-2021-4001, CVE-2023-1206, CVE-2023-3212, CVE-2023-3338,
CVE-2023-3863, CVE-2023-4194

Package Information:
https://launchpad.net/ubuntu/+source/linux/5.4.0-164.181
https://launchpad.net/ubuntu/+source/linux-aws/5.4.0-1111.120
https://launchpad.net/ubuntu/+source/linux-azure/5.4.0-1117.124
https://launchpad.net/ubuntu/+source/linux-bluefield/5.4.0-1072.78
https://launchpad.net/ubuntu/+source/linux-gcp/5.4.0-1115.124
https://launchpad.net/ubuntu/+source/linux-gkeop/5.4.0-1078.82
https://launchpad.net/ubuntu/+source/linux-ibm/5.4.0-1058.63
https://launchpad.net/ubuntu/+source/linux-iot/5.4.0-1023.24
https://launchpad.net/ubuntu/+source/linux-kvm/5.4.0-1100.106
https://launchpad.net/ubuntu/+source/linux-oracle/5.4.0-1110.119
https://launchpad.net/ubuntu/+source/linux-raspi/5.4.0-1095.106
https://launchpad.net/ubuntu/+source/linux-xilinx-zynqmp/5.4.0-1031.35