USN-4426-1: Linux kernel vulnerabilities

27 July 2020

Several security issues were fixed in the Linux kernel.

Releases

Packages

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-aws-hwe - Linux kernel for Amazon Web Services (AWS-HWE) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-azure-4.15 - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gcp-4.15 - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gke-4.15 - Linux kernel for Google Container Engine (GKE) systems
  • linux-hwe - Linux hardware enablement (HWE) kernel
  • 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

Details

Jason A. Donenfeld discovered that the ACPI implementation in the Linux
kernel did not properly restrict loading SSDT code from an EFI variable. A
privileged attacker could use this to bypass Secure Boot lockdown
restrictions and execute arbitrary code in the kernel. (CVE-2019-20908)

Fan Yang discovered that the mremap implementation in the Linux kernel did
not properly handle DAX Huge Pages. A local attacker with access to DAX
storage could use this to gain administrative privileges. (CVE-2020-10757)

Mauricio Faria de Oliveira discovered that the aufs implementation in the
Linux kernel improperly managed inode reference counts in the
vfsub_dentry_open() method. A local attacker could use this vulnerability
to cause a denial of service. (CVE-2020-11935)

Jason A. Donenfeld discovered that the ACPI implementation in the Linux
kernel did not properly restrict loading ACPI tables via configfs. A
privileged attacker could use this to bypass Secure Boot lockdown
restrictions and execute arbitrary code in the kernel. (CVE-2020-15780)

Update instructions

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

Ubuntu 18.04
Ubuntu 16.04

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.

Related notices

  • USN-4425-1: linux-image-5.4.0-1022-azure, linux-image-5.4.0-42-lowlatency, linux-image-oem, linux-image-5.4.0-42-generic-lpae, linux-image-azure-edge, linux-image-5.4.0-1021-gcp, linux-image-raspi2, linux-image-snapdragon-hwe-18.04, linux-hwe-5.4, linux-image-raspi-hwe-18.04, linux-image-virtual-hwe-18.04, linux-image-azure, linux-kvm, linux-image-5.4.0-30-generic, linux, linux-raspi, linux-raspi-5.4, linux-image-gcp, linux-image-generic-lpae-hwe-18.04, linux-aws, linux-azure, linux-gcp, linux-image-kvm, linux-image-lowlatency-hwe-18.04, linux-image-lowlatency, linux-image-generic-hwe-18.04, linux-oracle, linux-image-oracle, linux-image-5.4.0-1015-raspi, linux-image-5.4.0-1021-oracle, linux-image-generic-lpae, linux-image-gke, linux-image-raspi, linux-image-oem-osp1, linux-image-gkeop-5.4, linux-image-5.4.0-42-generic, linux-image-virtual, linux-image-generic, linux-azure-5.4, linux-riscv, linux-image-5.4.0-1020-aws, linux-image-aws
  • USN-4440-1: linux-gcp-5.3, linux-oracle-5.3, linux-image-raspi2-hwe-18.04, linux-image-5.3.0-64-lowlatency, linux-image-azure, linux-image-5.3.0-64-generic, linux-azure-5.3, linux-aws-5.3, linux-image-5.3.0-1030-raspi2, linux-image-5.3.0-1032-gke, linux-image-gcp, linux-image-gke-5.3, linux-gke-5.3, linux-hwe, linux-image-5.3.0-1030-oracle, linux-image-5.3.0-1032-aws, linux-image-5.3.0-1034-azure, linux-image-oracle, linux-image-5.3.0-64-generic-lpae, linux-image-gkeop-5.3, linux-image-5.3.0-1032-gcp, linux-raspi2-5.3, linux-image-aws
  • USN-4483-1: linux-image-oem, linux-image-5.4.0-45-lowlatency, linux-image-raspi2, linux-image-snapdragon-hwe-18.04, linux-hwe-5.4, linux-image-raspi-hwe-18.04, linux-image-virtual-hwe-18.04, linux-image-azure, linux-kvm, linux-image-5.4.0-1022-aws, linux, linux-image-5.4.0-1023-azure, linux-image-5.4.0-45-generic, linux-raspi, linux-raspi-5.4, linux-image-gcp, linux-image-generic-lpae-hwe-18.04, linux-aws, linux-azure, linux-gcp, linux-image-5.4.0-1022-gcp, linux-image-gke-5.4, linux-image-lowlatency-hwe-18.04, linux-image-lowlatency, linux-image-generic-hwe-18.04, linux-oracle, linux-image-oracle, linux-image-5.4.0-45-generic-lpae, linux-image-generic-lpae, linux-image-gke, linux-image-raspi, linux-image-oem-osp1, linux-image-gkeop-5.4, linux-aws-5.4, linux-image-5.4.0-1016-raspi, linux-oracle-5.4, linux-image-virtual, linux-image-aws-edge, linux-image-generic, linux-azure-5.4, linux-image-5.4.0-1022-oracle, linux-gcp-5.4, linux-image-kvm, linux-image-aws
  • USN-4427-1: linux-image-powerpc64-emb-lts-xenial, linux-image-snapdragon, linux-image-4.4.0-186-generic-lpae, linux-snapdragon, linux-image-powerpc64-smp-lts-xenial, linux-image-raspi2, linux-image-4.4.0-186-powerpc-smp, linux-kvm, linux-image-powerpc64-emb, linux-image-powerpc-smp, linux, linux-image-powerpc-e500mc, linux-aws, linux-image-4.4.0-186-powerpc64-smp, linux-image-4.4.0-186-powerpc64-emb, linux-image-4.4.0-1077-kvm, linux-image-generic-lts-xenial, linux-image-4.4.0-1111-aws, linux-image-4.4.0-1140-snapdragon, linux-image-4.4.0-1136-raspi2, linux-image-lowlatency-lts-xenial, linux-image-lowlatency, linux-image-4.4.0-186-generic, linux-image-4.4.0-186-powerpc-e500mc, linux-image-4.4.0-1075-aws, linux-image-generic-lpae, linux-lts-xenial, linux-image-powerpc-e500mc-lts-xenial, linux-image-virtual, linux-raspi2, linux-image-generic, linux-image-virtual-lts-xenial, linux-image-generic-lpae-lts-xenial, linux-image-powerpc-smp-lts-xenial, linux-image-powerpc64-smp, linux-image-4.4.0-186-lowlatency, linux-image-kvm, linux-image-aws
  • USN-4439-1: linux-image-oem-osp1, linux-oem-osp1, linux-image-5.0.0-1045-gke, linux-image-gke-5.0, linux-image-5.0.0-1065-oem-osp1, linux-gke-5.0