USN-4363-1: Linux kernel vulnerabilities

28 May 2020

linux, linux-aws, linux-aws-hwe, linux-azure, linux-azure-4.15, linux-gcp, linux-gke-4.15, linux-hwe, linux-kvm, linux-oem, linux-oracle, linux-raspi2, linux-snapdragon vulnerabilities

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

  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 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-4.15 - Linux kernel for Microsoft Azure Cloud systems
  • linux-gke-4.15 - Linux kernel for Google Container Engine (GKE) systems
  • linux-kvm - Linux kernel for cloud environments
  • linux-oem - Linux kernel for OEM systems
  • linux-oracle - Linux kernel for Oracle Cloud systems
  • linux-raspi2 - Linux kernel for Raspberry Pi (V7) systems
  • linux-snapdragon - Linux kernel for Qualcomm Snapdragon processors
  • linux-aws-hwe - Linux kernel for Amazon Web Services (AWS-HWE) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-hwe - Linux hardware enablement (HWE) kernel

Details

It was discovered that the Serial CAN interface driver in the Linux kernel did not properly initialize data. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2020-11494)

It was discovered that the linux kernel did not properly validate certain mount options to the tmpfs virtual memory file system. A local attacker with the ability to specify mount options could use this to cause a denial of service (system crash). (CVE-2020-11565)

David Gibson discovered that the Linux kernel on Power9 CPUs did not properly save and restore Authority Mask registers state in some situations. A local attacker in a guest VM could use this to cause a denial of service (host system crash). (CVE-2020-11669)

It was discovered that the block layer in the Linux kernel contained a race condition leading to a use-after-free vulnerability. A local attacker could possibly use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2020-12657)

Update instructions

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

Ubuntu 18.04 LTS
linux-image-4.15.0-101-generic - 4.15.0-101.102
linux-image-4.15.0-101-generic-lpae - 4.15.0-101.102
linux-image-4.15.0-101-lowlatency - 4.15.0-101.102
linux-image-4.15.0-1039-oracle - 4.15.0-1039.43
linux-image-4.15.0-1059-gke - 4.15.0-1059.62
linux-image-4.15.0-1060-kvm - 4.15.0-1060.61
linux-image-4.15.0-1062-raspi2 - 4.15.0-1062.66
linux-image-4.15.0-1067-aws - 4.15.0-1067.71
linux-image-4.15.0-1079-snapdragon - 4.15.0-1079.86
linux-image-4.15.0-1081-oem - 4.15.0-1081.91
linux-image-4.15.0-1083-azure - 4.15.0-1083.93
linux-image-aws-lts-18.04 - 4.15.0.1067.70
linux-image-azure-lts-18.04 - 4.15.0.1083.54
linux-image-generic - 4.15.0.101.91
linux-image-generic-lpae - 4.15.0.101.91
linux-image-gke - 4.15.0.1059.63
linux-image-gke-4.15 - 4.15.0.1059.63
linux-image-kvm - 4.15.0.1060.60
linux-image-lowlatency - 4.15.0.101.91
linux-image-oem - 4.15.0.1081.85
linux-image-oracle-lts-18.04 - 4.15.0.1039.48
linux-image-powerpc-e500mc - 4.15.0.101.91
linux-image-powerpc-smp - 4.15.0.101.91
linux-image-powerpc64-emb - 4.15.0.101.91
linux-image-powerpc64-smp - 4.15.0.101.91
linux-image-raspi2 - 4.15.0.1062.60
linux-image-snapdragon - 4.15.0.1079.82
linux-image-virtual - 4.15.0.101.91
Ubuntu 16.04 LTS
linux-image-4.15.0-101-generic - 4.15.0-101.102~16.04.1
linux-image-4.15.0-101-generic-lpae - 4.15.0-101.102~16.04.1
linux-image-4.15.0-101-lowlatency - 4.15.0-101.102~16.04.1
linux-image-4.15.0-1039-oracle - 4.15.0-1039.43~16.04.1
linux-image-4.15.0-1067-aws - 4.15.0-1067.71~16.04.1
linux-image-4.15.0-1071-gcp - 4.15.0-1071.81~16.04.1
linux-image-4.15.0-1083-azure - 4.15.0-1083.93~16.04.1
linux-image-aws-hwe - 4.15.0.1067.67
linux-image-azure - 4.15.0.1083.82
linux-image-azure-edge - 4.15.0.1083.82
linux-image-gcp - 4.15.0.1071.77
linux-image-generic-hwe-16.04 - 4.15.0.101.108
linux-image-generic-lpae-hwe-16.04 - 4.15.0.101.108
linux-image-gke - 4.15.0.1071.77
linux-image-lowlatency-hwe-16.04 - 4.15.0.101.108
linux-image-oem - 4.15.0.101.108
linux-image-oracle - 4.15.0.1039.32
linux-image-virtual-hwe-16.04 - 4.15.0.101.108

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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