USN-4576-1: Linux kernel vulnerabilities

14 October 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-5.4 - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-azure-5.4 - Linux kernel for Microsoft Azure cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gcp-5.4 - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-hwe-5.4 - Linux hardware enablement (HWE) kernel
  • linux-kvm - Linux kernel for cloud environments
  • linux-oracle - Linux kernel for Oracle Cloud systems
  • linux-oracle-5.4 - Linux kernel for Oracle Cloud systems
  • linux-raspi - Linux kernel for Raspberry Pi (V8) systems
  • linux-raspi-5.4 - Linux kernel for Raspberry Pi (V8) systems

Details

Hador Manor discovered that the DCCP protocol implementation in the Linux
kernel improperly handled socket reuse, leading to a use-after-free
vulnerability. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2020-16119)

Jay Shin discovered that the ext4 file system implementation in the Linux
kernel did not properly handle directory access with broken indexing,
leading to an out-of-bounds read vulnerability. A local attacker could use
this to cause a denial of service (system crash). (CVE-2020-14314)

David Alan Gilbert discovered that the XFS file system implementation in
the Linux kernel did not properly perform metadata validation in some
circumstances. A local attacker could use this to cause a denial of
service. (CVE-2020-14385)

Giuseppe Scrivano discovered that the overlay file system in the Linux
kernel did not properly perform permission checks in some situations. A
local attacker could possibly use this to bypass intended restrictions and
gain read access to restricted files. (CVE-2020-16120)

It was discovered that a race condition existed in the hugetlb sysctl
implementation in the Linux kernel. A privileged attacker could use this to
cause a denial of service (system crash). (CVE-2020-25285)

It was discovered that the block layer subsystem in the Linux kernel did
not properly handle zero-length requests. A local attacker could use this
to cause a denial of service. (CVE-2020-25641)

Update instructions

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

Ubuntu 20.04
Ubuntu 18.04

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-4580-1: linux-image-3.13.0-182-lowlatency, linux-image-lowlatency-pae, linux-image-3.2.0-149-virtual, linux-image-generic-lpae, linux-image-generic-lts-trusty, linux-lts-trusty, linux-image-lowlatency, linux-image-virtual, linux, linux-image-3.2.0-149-highbank, linux-image-3.13.0-182-generic-lpae, linux-image-3.2.0-149-generic-pae, linux-image-3.2.0-149-generic, linux-image-generic-pae, linux-image-3.2.0-149-omap, linux-image-highbank, linux-image-omap, linux-image-generic-lpae-lts-trusty, linux-image-generic, linux-image-3.13.0-182-generic, linux-image-server
  • USN-4579-1: linux-image-powerpc64-smp, linux-image-4.4.0-193-lowlatency, linux-image-generic-lpae, linux-image-4.4.0-193-powerpc-smp, linux-image-powerpc-e500mc, linux-image-4.4.0-193-powerpc64-emb, linux-image-4.4.0-193-powerpc-e500mc, linux-image-generic-lts-xenial, linux-image-lowlatency, linux-image-4.4.0-1117-aws, linux, linux-image-4.4.0-193-generic, linux-image-kvm, linux-image-4.4.0-1145-snapdragon, linux-image-4.4.0-193-generic-lpae, linux-image-virtual-lts-xenial, linux-lts-xenial, linux-aws, linux-image-powerpc-smp, linux-image-generic, linux-kvm, linux-image-snapdragon, linux-image-powerpc64-emb, linux-image-generic-lpae-lts-xenial, linux-image-raspi2, linux-image-aws, linux-image-4.4.0-1082-kvm, linux-image-lowlatency-lts-xenial, linux-snapdragon, linux-image-4.4.0-193-powerpc64-smp, linux-image-4.4.0-1141-raspi2, linux-raspi2, linux-image-virtual, linux-image-4.4.0-1081-aws
  • USN-4578-1: linux-image-4.15.0-1099-azure, linux-image-4.15.0-121-generic-lpae, linux-image-4.15.0-1056-oracle, linux-image-powerpc64-smp, linux-image-4.15.0-120-generic, linux-image-4.15.0-121-lowlatency, linux-image-gcp-lts-18.04, linux-image-generic-lpae, linux-image-azure, linux-image-azure-lts-18.04, linux-image-oracle-lts-18.04, linux-hwe, linux-image-powerpc-e500mc, linux-image-gke, linux-image-4.15.0-121-generic, linux-image-gcp, linux-image-lowlatency, linux-image-virtual, linux-image-4.15.0-1072-gke, linux, linux-image-4.15.0-1073-raspi2, linux-image-aws-hwe, linux-image-lowlatency-hwe-16.04, linux-image-4.15.0-120-generic-lpae, linux-image-4.15.0-1086-aws, linux-image-oracle, linux-image-4.15.0-1099-oem, linux-image-4.15.0-1085-aws, linux-oracle, linux-image-4.15.0-1057-oracle, linux-image-kvm, linux-oem, linux-image-4.15.0-1086-gcp, linux-aws, linux-image-generic-hwe-16.04, linux-image-powerpc-smp, linux-gke-4.15, linux-image-oem, linux-azure-4.15, linux-gcp-4.15, linux-image-generic, linux-kvm, linux-image-snapdragon, linux-image-virtual-hwe-16.04, linux-image-powerpc64-emb, linux-aws-hwe, linux-azure, linux-image-4.15.0-1098-azure, linux-image-raspi2, linux-image-aws-lts-18.04, linux-image-4.15.0-1077-kvm, linux-gcp, linux-snapdragon, linux-image-gke-4.15, linux-image-generic-lpae-hwe-16.04, linux-image-4.15.0-1089-snapdragon, linux-raspi2, linux-image-4.15.0-120-lowlatency
  • USN-4577-1: linux-image-raspi2-hwe-18.04, linux-image-gke-5.3, linux-gke-5.3, linux-image-gke-5.0, linux-oem-osp1, linux-image-5.3.0-1038-gke, linux-image-5.3.0-68-generic, linux-image-5.3.0-68-lowlatency, linux-image-gkeop-5.3, linux-image-oem-osp1, linux-raspi2-5.3, linux-gke-5.0, linux-hwe, linux-image-5.3.0-1035-raspi2, linux-image-5.0.0-1069-oem-osp1, linux-image-5.0.0-1049-gke