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USN-4750-1: Linux kernel vulnerabilities

25 February 2021

Several security issues were fixed in the Linux kernel.

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

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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-gke-5.4 - Linux kernel for Google Container Engine (GKE) systems
  • linux-gkeop - Linux kernel for Google Container Engine (GKE) systems
  • linux-gkeop-5.4 - Linux kernel for Google Container Engine (GKE) 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

Bodong Zhao discovered a use-after-free in the Sun keyboard driver
implementation in the Linux kernel. A local attacker could use this to
cause a denial of service or possibly execute arbitrary code.
(CVE-2020-25669)

It was discovered that the jfs file system implementation in the Linux
kernel contained an out-of-bounds read vulnerability. A local attacker
could use this to possibly cause a denial of service (system crash).
(CVE-2020-27815)

Shisong Qin and Bodong Zhao discovered that Speakup screen reader driver in
the Linux kernel did not correctly handle setting line discipline in some
situations. A local attacker could use this to cause a denial of service
(system crash). (CVE-2020-27830, CVE-2020-28941)

It was discovered that an information leak existed in the syscall
implementation in the Linux kernel on 32 bit systems. A local attacker
could use this to expose sensitive information (kernel memory).
(CVE-2020-28588)

Michael Kurth and Pawel Wieczorkiewicz discovered that the Xen event
processing backend in the Linux kernel did not properly limit the number of
events queued. An attacker in a guest VM could use this to cause a denial
of service in the host OS. (CVE-2020-29568)

Olivier Benjamin and Pawel Wieczorkiewicz discovered a race condition the
Xen paravirt block backend in the Linux kernel, leading to a use-after-free
vulnerability. An attacker in a guest VM could use this to cause a denial
of service in the host OS. (CVE-2020-29569)

Jann Horn discovered that the tty subsystem of the Linux kernel did not use
consistent locking in some situations, leading to a read-after-free
vulnerability. A local attacker could use this to cause a denial of service
(system crash) or possibly expose sensitive information (kernel memory).
(CVE-2020-29660)

Jann Horn discovered a race condition in the tty subsystem of the Linux
kernel in the locking for the TIOCSPGRP ioctl(), 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-2020-29661)

It was discovered that the netfilter subsystem in the Linux kernel did not
properly handle filter rules in some situations. A local attacker with the
CAP_NET_ADMIN capability could use this to cause a denial of service.
(CVE-2021-20177)

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro

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-4708-1: linux-image-lowlatency-lts-vivid, linux-image-generic-lts-utopic, linux-image-powerpc-smp-lts-xenial, linux-image-powerpc64-smp, linux-image-4.4.0-201-powerpc-smp, linux-image-powerpc64-emb-lts-xenial, linux-image-4.4.0-201-powerpc64-emb, linux-image-powerpc64-emb, linux-image-powerpc64-emb-lts-utopic, linux-lts-xenial, linux-image-4.4.0-201-powerpc64-smp, linux-image-generic-lts-xenial, linux-image-4.4.0-201-powerpc-e500mc, linux-image-powerpc-e500mc-lts-utopic, linux-image-generic-lpae-lts-utopic, linux-image-powerpc-e500mc, linux-image-lowlatency, linux-image-powerpc64-smp-lts-wily, linux-image-powerpc-smp-lts-utopic, linux-image-generic-lpae-lts-vivid, linux-image-virtual-lts-utopic, linux-image-generic-lpae, linux, linux-image-virtual-lts-wily, linux-image-lowlatency-lts-xenial, linux-image-powerpc64-smp-lts-vivid, linux-image-4.4.0-201-generic, linux-image-powerpc64-emb-lts-wily, linux-image-virtual-lts-xenial, linux-image-4.4.0-201-lowlatency, linux-image-generic-lpae-lts-wily, linux-image-powerpc-e500mc-lts-wily, linux-image-generic-lts-vivid, linux-image-powerpc64-smp-lts-xenial, linux-image-powerpc-smp-lts-vivid, linux-image-powerpc64-emb-lts-vivid, linux-image-virtual-lts-vivid, linux-image-virtual, linux-image-powerpc-e500mc-lts-vivid, linux-image-generic-lpae-lts-xenial, linux-image-powerpc-smp, linux-image-powerpc-smp-lts-wily, linux-image-powerpc64-smp-lts-utopic, linux-image-lowlatency-lts-wily, linux-image-lowlatency-lts-utopic, linux-image-generic-lts-wily, linux-image-powerpc-e500mc-lts-xenial, linux-image-4.4.0-201-generic-lpae, linux-image-generic
  • USN-4709-1: linux-image-4.4.0-1085-aws, linux-raspi2, linux-snapdragon, linux-aws, linux-image-4.4.0-1149-snapdragon, linux-image-snapdragon, linux-kvm, linux-image-4.4.0-1087-kvm, linux-image-raspi2, linux-image-4.4.0-1121-aws, linux-image-kvm, linux-image-aws, linux-image-4.4.0-1145-raspi2
  • USN-4749-1: linux-image-4.15.0-1085-kvm, linux-snapdragon, linux-hwe, linux-image-generic-lpae-hwe-16.04-edge, linux-image-dell300x, linux-image-4.15.0-1093-gcp, linux-image-4.15.0-1012-dell300x, linux-image-snapdragon, linux-azure-4.15, linux-image-virtual-hwe-16.04-edge, linux-image-oem, linux-aws-hwe, linux-image-lowlatency, linux-image-4.15.0-1094-aws, linux-image-lowlatency-hwe-16.04-edge, linux-image-4.15.0-1108-azure, linux-image-generic-hwe-16.04-edge, linux-raspi2, linux-image-generic-hwe-16.04, linux-image-4.15.0-136-lowlatency, linux-image-generic, linux-aws, linux-oracle, linux-image-lowlatency-hwe-16.04, linux-image-generic-lpae-hwe-16.04, linux-image-aws-lts-18.04, linux-image-generic-lpae, linux-image-oracle, linux, linux-image-4.15.0-136-generic, linux-image-azure-lts-18.04, linux-image-azure-edge, linux-image-virtual-hwe-16.04, linux-gcp-4.15, linux-kvm, linux-image-4.15.0-1079-raspi2, linux-image-gke, linux-image-raspi2, linux-gke-4.15, linux-image-4.15.0-136-generic-lpae, linux-image-virtual, linux-azure, linux-image-azure, linux-dell300x, linux-gcp, linux-image-aws-hwe, linux-image-oracle-lts-18.04, linux-image-4.15.0-1079-gke, linux-image-gcp, linux-image-kvm, linux-image-gke-4.15, linux-image-4.15.0-1096-snapdragon, linux-image-4.15.0-1065-oracle, linux-image-gcp-lts-18.04
  • USN-4751-1: linux-hwe-5.8, linux-image-raspi, linux-image-generic-hwe-20.04, linux-image-5.8.0-44-generic-lpae, linux-image-generic-lpae-hwe-20.04-edge, linux-image-lowlatency, linux-image-generic-64k-hwe-20.04, linux-image-5.8.0-44-generic-64k, linux-aws, linux-oracle, linux-image-generic-lpae, linux-image-oracle, linux, linux-image-aws, linux-image-generic-64k, linux-image-generic-hwe-20.04-edge, linux-image-5.8.0-1021-oracle, linux-image-virtual-hwe-20.04, linux-raspi, linux-image-5.8.0-44-lowlatency, linux-kvm, linux-image-5.8.0-1023-azure, linux-image-gke, linux-image-5.8.0-1016-raspi-nolpae, linux-image-lowlatency-hwe-20.04-edge, linux-image-virtual-hwe-20.04-edge, linux-image-generic-lpae-hwe-20.04, linux-image-virtual, linux-azure, linux-image-azure, linux-gcp, linux-image-oem-20.04, linux-image-5.8.0-1024-aws, linux-image-generic-64k-hwe-20.04-edge, linux-image-lowlatency-hwe-20.04, linux-image-5.8.0-1023-gcp, linux-image-gcp, linux-image-5.8.0-1016-raspi, linux-image-raspi-nolpae, linux-image-kvm, linux-image-5.8.0-44-generic, linux-image-5.8.0-1019-kvm, linux-image-generic
  • USN-4912-1: linux-oem-5.6, linux-image-5.6.0-1053-oem, linux-image-oem-20.04
  • USN-4752-1: linux-oem-5.6, linux-image-5.6.0-1048-oem, linux-image-oem-20.04
  • USN-4748-1: linux-image-lowlatency-lts-vivid, linux-image-generic-lts-utopic, linux-image-powerpc-smp-lts-xenial, linux-image-powerpc64-smp, linux-image-4.4.0-1146-raspi2, linux-snapdragon, linux-image-powerpc64-emb-lts-xenial, linux-image-4.4.0-203-powerpc-smp, linux-image-powerpc64-emb, linux-image-powerpc64-emb-lts-utopic, linux-image-snapdragon, linux-lts-xenial, linux-image-generic-lts-xenial, linux-image-powerpc-e500mc-lts-utopic, linux-image-generic-lpae-lts-utopic, linux-image-powerpc-e500mc, linux-image-lowlatency, linux-image-4.4.0-203-lowlatency, linux-image-4.4.0-1088-kvm, linux-image-4.4.0-203-generic-lpae, linux-raspi2, linux-image-powerpc64-smp-lts-wily, linux-image-powerpc-smp-lts-utopic, linux-aws, linux-image-generic-lpae-lts-vivid, linux-image-virtual-lts-utopic, linux-image-generic-lpae, linux, linux-image-aws, linux-image-virtual-lts-wily, linux-image-4.4.0-203-powerpc64-emb, linux-image-lowlatency-lts-xenial, linux-image-generic-lts-wily, linux-image-4.4.0-203-powerpc64-smp, linux-image-powerpc64-smp-lts-vivid, linux-image-virtual-lts-xenial, linux-image-powerpc64-emb-lts-wily, linux-image-generic-lpae-lts-wily, linux-kvm, linux-image-powerpc-e500mc-lts-wily, linux-image-raspi2, linux-image-powerpc64-smp-lts-xenial, linux-image-powerpc-smp-lts-vivid, linux-image-powerpc64-emb-lts-vivid, linux-image-virtual-lts-vivid, linux-image-virtual, linux-image-4.4.0-1150-snapdragon, linux-image-powerpc-e500mc-lts-vivid, linux-image-generic-lpae-lts-xenial, linux-image-powerpc-smp, linux-image-powerpc-smp-lts-wily, linux-image-4.4.0-203-generic, linux-image-powerpc64-smp-lts-utopic, linux-image-4.4.0-203-powerpc-e500mc, linux-image-lowlatency-lts-wily, linux-image-lowlatency-lts-utopic, linux-image-kvm, linux-image-generic-lts-vivid, linux-image-powerpc-e500mc-lts-xenial, linux-image-4.4.0-1086-aws, linux-image-4.4.0-1122-aws, linux-image-generic
  • USN-5130-1: linux-modules-3.13.0-188-powerpc-e500mc, linux-image-powerpc64-smp, linux-headers-powerpc-smp, linux-headers-3.13.0-188-lowlatency, linux-signed-image-generic-lts-quantal, linux-buildinfo-3.13.0-188-powerpc64-emb, linux-tools-common, linux-headers-generic-lts-trusty, linux-image-powerpc-e500mc, linux-cloud-tools-3.13.0-188-lowlatency, linux-headers-powerpc64-emb, linux-headers-highbank, linux-headers-powerpc-e500, linux-tools-generic-lpae, linux-image-generic-lts-raring, linux-image-highbank, linux, linux-headers-generic-pae, linux-generic-lts-saucy-eol-upgrade, linux-image-hwe-generic-trusty, linux-generic-lts-saucy, linux-tools-virtual, linux-modules-3.13.0-188-powerpc64-smp, linux-headers-3.13.0-188-powerpc-smp, linux-hwe-generic-trusty, linux-image-unsigned-3.13.0-188-lowlatency, linux-headers-3.13.0-188-generic-lpae, linux-headers-3.13.0-188-powerpc64-emb, linux-buildinfo-3.13.0-188-powerpc64-smp, linux-lowlatency, linux-tools-3.13.0-188, linux-image-server, linux-image-3.13.0-188-powerpc-e500mc, linux-generic-lpae-lts-saucy-eol-upgrade, linux-modules-3.13.0-188-powerpc64-emb, linux-image-generic-lts-trusty, linux-headers-generic-lts-quantal, linux-hwe-virtual-trusty, linux-image-3.13.0-188-lowlatency, linux-modules-3.13.0-188-powerpc-smp, linux-signed-generic-lts-saucy-eol-upgrade, linux-generic, linux-headers-3.13.0-188-powerpc64-smp, linux-buildinfo-3.13.0-188-powerpc-e500, linux-headers-3.13.0-188, linux-signed-image-generic, linux-tools-generic-lts-trusty, linux-omap, linux-tools-3.13.0-188-powerpc64-emb, linux-tools-lts-trusty, linux-headers-omap, linux-modules-extra-3.13.0-188-generic, linux-signed-generic-lts-trusty, linux-buildinfo-3.13.0-188-powerpc-smp, linux-powerpc64-smp, linux-image-generic-lpae-lts-trusty, linux-signed-generic, linux-headers-powerpc64-smp, hv-kvp-daemon-init, linux-signed-image-generic-lts-raring, linux-tools-powerpc-e500mc, linux-headers-generic-lts-raring, linux-generic-lts-trusty, linux-tools-powerpc64-emb, linux-modules-3.13.0-188-powerpc-e500, linux-tools-generic-lpae-lts-saucy, linux-image-powerpc-smp, linux-cloud-tools-lowlatency, linux-headers-lowlatency, linux-modules-3.13.0-188-generic-lpae, linux-image-generic-pae, linux-tools-generic, linux-tools-3.13.0-188-generic, linux-tools-3.13.0-188-powerpc-e500mc, linux-buildinfo-3.13.0-188-generic, linux-image-3.13.0-188-powerpc64-emb, linux-image-generic-lts-saucy, linux-generic-lpae-lts-trusty, linux-signed-generic-lts-quantal, linux-powerpc-e500mc, linux-tools-lowlatency, linux-buildinfo-3.13.0-188-lowlatency, linux-tools-powerpc64-smp, linux-cloud-tools-3.13.0-188-generic, linux-image-hwe-virtual-trusty, linux-modules-3.13.0-188-generic, linux-cloud-tools-generic, linux-cloud-tools-virtual, linux-crashdump, linux-headers-generic-lpae-lts-trusty, linux-tools-lts-quantal, linux-cloud-tools-3.13.0-188, linux-headers-virtual, linux-generic-lpae-lts-saucy, linux-image-3.13.0-188-generic, linux-tools-3.13.0-188-powerpc64-smp, linux-image-unsigned-3.13.0-188-generic, linux-source, linux-image-extra-virtual, linux-modules-3.13.0-188-lowlatency, linux-libc-dev, linux-generic-lpae, linux-tools-powerpc-smp, linux-image-virtual, linux-generic-pae, linux-generic-lts-quantal, linux-headers-server, linux-image-3.13.0-188-powerpc-smp, linux-tools-generic-lts-saucy, linux-image-generic-lts-quantal, linux-image-lowlatency-pae, linux-cloud-tools-common, linux-headers-3.13.0-188-powerpc-e500mc, linux-tools-3.13.0-188-powerpc-smp, linux-headers-generic-lpae, linux-image-generic-lpae-lts-saucy, linux-signed-generic-lts-raring, linux-signed-generic-lts-saucy, linux-image-powerpc-e500, linux-image-powerpc64-emb, linux-headers-3.13.0-188-generic, linux-highbank, linux-doc, linux-image-3.13.0-188-generic-lpae, linux-signed-generic-lts-raring-eol-upgrade, linux-buildinfo-3.13.0-188-powerpc-e500mc, linux-tools-3.13.0-188-powerpc-e500, linux-image-lowlatency, linux-tools-powerpc-e500, linux-powerpc64-emb, linux-signed-generic-lts-quantal-eol-upgrade, linux-powerpc-smp, linux-image-generic-lpae, linux-headers-lowlatency-pae, linux-image-3.13.0-188-powerpc-e500, linux-image-omap, linux-powerpc-e500, linux-tools-lts-saucy, linux-virtual, linux-headers-generic-lts-saucy, linux-tools-3.13.0-188-lowlatency, linux-generic-lts-raring, linux-signed-image-generic-lts-trusty, linux-tools-3.13.0-188-generic-lpae, linux-tools-generic-lpae-lts-trusty, linux-headers-powerpc-e500mc, linux-server, linux-generic-lts-raring-eol-upgrade, linux-buildinfo-3.13.0-188-generic-lpae, linux-generic-lts-quantal-eol-upgrade, linux-source-3.13.0, linux-signed-image-generic-lts-saucy, linux-headers-3.13.0-188-powerpc-e500, linux-headers-generic, linux-headers-generic-lpae-lts-saucy, linux-lowlatency-pae, linux-tools-lts-raring, linux-image-3.13.0-188-powerpc64-smp, linux-image-generic
  • LSN-0082-1: generic-4.15, gke-5.4, generic-4.4, gkeop, lowlatency-4.15, generic-5.4, lowlatency-4.4, oem, gke, gkeop-5.4, lowlatency-5.4, gcp, gke-4.15
  • USN-4876-1: linux-image-lowlatency-lts-vivid, linux-image-generic-lts-utopic, linux-image-powerpc-smp-lts-xenial, linux-image-powerpc64-smp, linux-image-4.4.0-204-powerpc64-smp, linux-snapdragon, linux-image-powerpc64-emb-lts-xenial, linux-image-powerpc64-emb, linux-image-powerpc64-emb-lts-utopic, linux-image-snapdragon, linux-lts-xenial, linux-image-4.4.0-1151-snapdragon, linux-image-generic-lts-xenial, linux-image-powerpc-e500mc-lts-utopic, linux-image-generic-lpae-lts-utopic, linux-image-powerpc-e500mc, linux-image-4.4.0-1123-aws, linux-image-lowlatency, linux-raspi2, linux-image-4.4.0-204-powerpc-e500mc, linux-image-powerpc64-smp-lts-wily, linux-image-powerpc-smp-lts-utopic, linux-image-4.4.0-204-generic-lpae, linux-aws, linux-image-generic-lpae-lts-vivid, linux-image-4.4.0-204-generic, linux-image-virtual-lts-utopic, linux-image-generic-lpae, linux, linux-image-aws, linux-image-4.4.0-1087-aws, linux-image-virtual-lts-wily, linux-image-lowlatency-lts-xenial, linux-image-generic-lts-wily, linux-image-powerpc64-smp-lts-vivid, linux-image-virtual-lts-xenial, linux-image-powerpc64-emb-lts-wily, linux-image-generic-lpae-lts-wily, linux-image-4.4.0-1147-raspi2, linux-kvm, linux-image-powerpc-e500mc-lts-wily, linux-image-4.4.0-204-powerpc-smp, linux-image-raspi2, linux-image-4.4.0-204-powerpc64-emb, linux-image-powerpc64-smp-lts-xenial, linux-image-powerpc-smp-lts-vivid, linux-image-4.4.0-204-lowlatency, linux-image-powerpc64-emb-lts-vivid, linux-image-virtual-lts-vivid, linux-image-virtual, linux-image-powerpc-e500mc-lts-vivid, linux-image-generic-lpae-lts-xenial, linux-image-powerpc-smp, linux-image-powerpc-smp-lts-wily, linux-image-powerpc64-smp-lts-utopic, linux-image-lowlatency-lts-wily, linux-image-lowlatency-lts-utopic, linux-image-kvm, linux-image-generic-lts-vivid, linux-image-powerpc-e500mc-lts-xenial, linux-image-4.4.0-1089-kvm, linux-image-generic