==========================================================================
Ubuntu Security Notice USN-5091-1
September 28, 2021

linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp,
linux-gcp-5.4, linux-gke, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4,
linux-hwe-5.4, linux-kvm, linux-oracle, linux-oracle-5.4 vulnerabilities
==========================================================================

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

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

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-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-gke: Linux kernel for Google Container Engine (GKE) systems
- linux-gkeop: Linux kernel for Google Container Engine (GKE) systems
- linux-kvm: Linux kernel for cloud environments
- linux-oracle: Linux kernel for Oracle Cloud systems
- 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-gke-5.4: Linux kernel for Google Container Engine (GKE) systems
- linux-gkeop-5.4: Linux kernel for Google Container Engine (GKE) systems
- linux-hwe-5.4: Linux hardware enablement (HWE) kernel
- linux-oracle-5.4: Linux kernel for Oracle Cloud systems

Details:

Ofek Kirzner, Adam Morrison, Benedict Schlueter, and Piotr Krysiuk
discovered that the BPF verifier in the Linux kernel missed possible
mispredicted branches due to type confusion, allowing a side-channel
attack. An attacker could use this to expose sensitive information.
(CVE-2021-33624)

It was discovered that the tracing subsystem in the Linux kernel did not
properly keep track of per-cpu ring buffer state. A privileged attacker
could use this to cause a denial of service. (CVE-2021-3679)

Alexey Kardashevskiy discovered that the KVM implementation for PowerPC
systems in the Linux kernel did not properly validate RTAS arguments in
some situations. An attacker in a guest vm could use this to cause a denial
of service (host OS crash) or possibly execute arbitrary code.
(CVE-2021-37576)

It was discovered that the Virtio console implementation in the Linux
kernel did not properly validate input lengths in some situations. A local
attacker could possibly use this to cause a denial of service (system
crash). (CVE-2021-38160)

Michael Wakabayashi discovered that the NVSv4 client implementation in the
Linux kernel did not properly order connection setup operations. An
attacker controlling a remote NFS server could use this to cause a denial
of service on the client. (CVE-2021-38199)

It was discovered that the MAX-3421 host USB device driver in the Linux
kernel did not properly handle device removal events. A physically
proximate attacker could use this to cause a denial of service (system
crash). (CVE-2021-38204)

Update instructions:

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

Ubuntu 20.04 LTS:
  linux-image-5.4.0-1024-gkeop    5.4.0-1024.25
  linux-image-5.4.0-1047-kvm      5.4.0-1047.49
  linux-image-5.4.0-1053-gcp      5.4.0-1053.57
  linux-image-5.4.0-1053-gke      5.4.0-1053.56
  linux-image-5.4.0-1055-oracle   5.4.0-1055.59
  linux-image-5.4.0-1057-aws      5.4.0-1057.60
  linux-image-5.4.0-1059-azure    5.4.0-1059.62
  linux-image-5.4.0-88-generic    5.4.0-88.99
  linux-image-5.4.0-88-generic-lpae  5.4.0-88.99
  linux-image-5.4.0-88-lowlatency  5.4.0-88.99
  linux-image-aws-lts-20.04       5.4.0.1057.60
  linux-image-azure-lts-20.04     5.4.0.1059.57
  linux-image-gcp-lts-20.04       5.4.0.1053.63
  linux-image-generic             5.4.0.88.92
  linux-image-generic-lpae        5.4.0.88.92
  linux-image-gke                 5.4.0.1053.63
  linux-image-gke-5.4             5.4.0.1053.63
  linux-image-gkeop               5.4.0.1024.27
  linux-image-gkeop-5.4           5.4.0.1024.27
  linux-image-kvm                 5.4.0.1047.46
  linux-image-lowlatency          5.4.0.88.92
  linux-image-oem                 5.4.0.88.92
  linux-image-oem-osp1            5.4.0.88.92
  linux-image-oracle-lts-20.04    5.4.0.1055.55
  linux-image-virtual             5.4.0.88.92

Ubuntu 18.04 LTS:
  linux-image-5.4.0-1024-gkeop    5.4.0-1024.25~18.04.1
  linux-image-5.4.0-1053-gcp      5.4.0-1053.57~18.04.1
  linux-image-5.4.0-1053-gke      5.4.0-1053.56~18.04.1
  linux-image-5.4.0-1055-oracle   5.4.0-1055.59~18.04.1
  linux-image-5.4.0-1057-aws      5.4.0-1057.60~18.04.1
  linux-image-5.4.0-1059-azure    5.4.0-1059.62~18.04.1
  linux-image-5.4.0-87-generic    5.4.0-87.98~18.04.1
  linux-image-5.4.0-87-generic-lpae  5.4.0-87.98~18.04.1
  linux-image-5.4.0-87-lowlatency  5.4.0-87.98~18.04.1
  linux-image-aws                 5.4.0.1057.40
  linux-image-azure               5.4.0.1059.39
  linux-image-gcp                 5.4.0.1053.39
  linux-image-generic-hwe-18.04   5.4.0.87.98~18.04.78
  linux-image-generic-lpae-hwe-18.04  5.4.0.87.98~18.04.78
  linux-image-gke-5.4             5.4.0.1053.56~18.04.18
  linux-image-gkeop-5.4           5.4.0.1024.25~18.04.25
  linux-image-lowlatency-hwe-18.04  5.4.0.87.98~18.04.78
  linux-image-oem                 5.4.0.87.98~18.04.78
  linux-image-oem-osp1            5.4.0.87.98~18.04.78
  linux-image-oracle              5.4.0.1055.59~18.04.35
  linux-image-snapdragon-hwe-18.04  5.4.0.87.98~18.04.78
  linux-image-virtual-hwe-18.04   5.4.0.87.98~18.04.78

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-5091-1
  CVE-2021-33624, CVE-2021-3679, CVE-2021-37576, CVE-2021-38160,
  CVE-2021-38199, CVE-2021-38204

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.4.0-88.99
  https://launchpad.net/ubuntu/+source/linux-aws/5.4.0-1057.60
  https://launchpad.net/ubuntu/+source/linux-azure/5.4.0-1059.62
  https://launchpad.net/ubuntu/+source/linux-gcp/5.4.0-1053.57
  https://launchpad.net/ubuntu/+source/linux-gke/5.4.0-1053.56
  https://launchpad.net/ubuntu/+source/linux-gkeop/5.4.0-1024.25
  https://launchpad.net/ubuntu/+source/linux-kvm/5.4.0-1047.49
  https://launchpad.net/ubuntu/+source/linux-oracle/5.4.0-1055.59
  https://launchpad.net/ubuntu/+source/linux-aws-5.4/5.4.0-1057.60~18.04.1
  https://launchpad.net/ubuntu/+source/linux-azure-5.4/5.4.0-1059.62~18.04.1
  https://launchpad.net/ubuntu/+source/linux-gcp-5.4/5.4.0-1053.57~18.04.1
  https://launchpad.net/ubuntu/+source/linux-gke-5.4/5.4.0-1053.56~18.04.1
  https://launchpad.net/ubuntu/+source/linux-gkeop-5.4/5.4.0-1024.25~18.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe-5.4/5.4.0-87.98~18.04.1
  https://launchpad.net/ubuntu/+source/linux-oracle-5.4/5.4.0-1055.59~18.04.1