USN-4463-1: Linux kernel vulnerabilities

18 August 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-kvm - Linux kernel for cloud environments
  • linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty
  • linux-raspi2 - Linux kernel for Raspberry Pi (V7) systems
  • linux-snapdragon - Linux kernel for Qualcomm Snapdragon processors

Details

It was discovered that the bcache subsystem in the Linux kernel did not
properly release a lock in some error conditions. A local attacker could
possibly use this to cause a denial of service. (CVE-2020-12771)

Kyungtae Kim discovered that the USB testing driver in the Linux kernel did
not properly deallocate memory on disconnect events. A physically proximate
attacker could use this to cause a denial of service (memory exhaustion).
(CVE-2020-15393)

Update instructions

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

Ubuntu 16.04
Ubuntu 14.04

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-4485-1: linux-image-powerpc64-emb, linux-gcp-4.15, linux-image-aws-hwe, linux-image-4.15.0-1080-aws, linux-image-azure-edge, linux-image-4.15.0-1051-oracle, linux-image-aws-lts-18.04, linux-azure, linux-image-generic-hwe-16.04, linux-image-gke, linux-image-4.15.0-115-generic, linux-image-gcp-lts-18.04, linux-image-4.15.0-115-generic-lpae, linux-image-powerpc-e500mc, linux-aws, linux, linux-image-4.15.0-1067-gke, linux-image-4.15.0-1081-gcp, linux-image-4.15.0-1068-raspi2, linux-image-oracle, linux-gke-4.15, linux-image-snapdragon, linux-image-4.15.0-1084-snapdragon, linux-oracle, linux-aws-hwe, linux-image-gke-4.15, linux-image-gcp, linux-image-lowlatency-hwe-16.04, linux-image-raspi2, linux-hwe, linux-image-4.15.0-1072-kvm, linux-image-azure, linux-image-azure-lts-18.04, linux-image-virtual, linux-image-lowlatency, linux-snapdragon, linux-kvm, linux-azure-4.15, linux-image-4.15.0-1093-azure, linux-image-oracle-lts-18.04, linux-image-virtual-hwe-16.04, linux-image-generic-lpae-hwe-16.04, linux-image-oem, linux-image-powerpc64-smp, linux-image-4.15.0-1094-oem, linux-image-4.15.0-115-lowlatency, linux-image-generic, linux-image-powerpc-smp, linux-oem, linux-raspi2, linux-image-generic-lpae, linux-image-kvm, linux-gcp
  • USN-4462-1: linux-image-5.0.0-1046-gke, linux-image-gke-5.0, linux-image-5.0.0-1067-oem-osp1, linux-oem-osp1, linux-image-oem-osp1, linux-gke-5.0
  • USN-4483-1: linux-aws-5.4, linux-image-5.4.0-1023-azure, linux-image-generic-lpae-hwe-18.04, linux-image-virtual-hwe-18.04, linux-azure, linux-hwe-5.4, linux-image-raspi-hwe-18.04, linux-image-gke, linux-raspi, linux-image-5.4.0-1016-raspi, linux-aws, linux-gcp-5.4, linux, linux-image-aws-edge, linux-image-gke-5.4, linux-image-5.4.0-1022-oracle, linux-image-oracle, linux-oracle, linux-image-oem-osp1, linux-image-raspi2, linux-image-gcp, linux-azure-5.4, linux-image-snapdragon-hwe-18.04, linux-oracle-5.4, linux-image-gkeop-5.4, linux-raspi-5.4, linux-image-lowlatency-hwe-18.04, linux-image-azure, linux-image-virtual, linux-image-lowlatency, linux-image-5.4.0-1022-aws, linux-image-aws, linux-kvm, linux-image-5.4.0-45-generic-lpae, linux-image-oem, linux-image-5.4.0-45-generic, linux-image-raspi, linux-image-5.4.0-1022-gcp, linux-image-generic, linux-image-5.4.0-45-lowlatency, linux-image-generic-hwe-18.04, linux-image-generic-lpae, linux-image-kvm, linux-gcp
  • USN-4465-1: linux-hwe, linux-image-5.3.0-1033-aws, linux-image-gkeop-5.3, linux-image-5.3.0-65-lowlatency, linux-image-5.3.0-65-generic, linux-image-azure, linux-image-5.3.0-1033-gke, linux-aws-5.3, linux-gke-5.3, linux-image-gke-5.3, linux-image-aws, linux-azure-5.3, linux-image-5.3.0-1035-azure