LSN-0081-1: Kernel Live Patch Security Notice

13 September 2021

Several security issues were fixed in the kernel.

Releases

Software Description

  • gcp - Linux kernel for Google Cloud Platform (GCP) systems - (>= 5.4.0-1009)
  • generic-4.15 - Linux hardware enablement (HWE) kernel - (>= 4.15.0-69, >= 4.15.0-69)
  • generic-4.4 - Linux kernel - (>= 4.4.0-168, >= 4.4.0-211, >= 4.4.0-168)
  • generic-5.4 - Linux kernel - (>= 5.4.0-26, >= 5.4.0-26)
  • gke - Linux kernel for Google Container Engine (GKE) systems - (>= 5.4.0-1033)
  • gke-4.15 - Linux kernel for Google Container Engine (GKE) systems - (>= 4.15.0-1076)
  • gke-5.4 - Linux kernel for Google Container Engine (GKE) systems - (>= 5.4.0-1009)
  • gkeop - Linux kernel for Google Container Engine (GKE) systems - (>= 5.4.0-1009)
  • gkeop-5.4 - Linux kernel for Google Container Engine (GKE) systems - (>= 5.4.0-1007)
  • lowlatency-4.15 - Linux hardware enablement (HWE) kernel - (>= 4.15.0-69, >= 4.15.0-69)
  • lowlatency-4.4 - Linux kernel - (>= 4.4.0-168, >= 4.4.0-211, >= 4.4.0-168)
  • lowlatency-5.4 - Linux kernel - (>= 5.4.0-26, >= 5.4.0-26)
  • oem - Linux kernel for OEM systems - (>= 4.15.0-1063)

Details

Maxim Levitsky discovered that the KVM hypervisor implementation for AMD
processors in the Linux kernel did not properly prevent a guest VM from
enabling AVIC in nested guest VMs. An attacker in a guest VM could use this
to write to portions of the host's physical memory.(CVE-2021-3653)

Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor
implementation for AMD processors in the Linux kernel allowed a guest VM to
disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a
guest VM could use this to read or write portions of the host's physical
memory.(CVE-2021-3656)

Andy Nguyen discovered that the netfilter subsystem in the Linux kernel
contained an out-of-bounds write in its setsockopt() implementation. A
local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code.(CVE-2021-22555)

It was discovered that the virtual file system implementation in the Linux
kernel contained an unsigned to signed integer conversion error. A local
attacker could use this to cause a denial of service (system crash) or
execute arbitrary code.(CVE-2021-33909)

Checking update status

The problem can be corrected in these Livepatch versions:

Kernel type 20.04 18.04 16.04 14.04
gcp 81.1
generic-4.15 81.1 81.1
generic-4.4 81.1 81.1
generic-5.4 81.1 81.1
gke 81.1
gke-4.15 81.1
gke-5.4 81.1
gkeop 81.1
gkeop-5.4 81.1
lowlatency-4.15 81.1 81.1
lowlatency-4.4 81.1 81.1
lowlatency-5.4 81.1 81.1
oem 81.1

To check your kernel type and Livepatch version, enter this command: