1. Ubuntu Security Notices
  2. USN-4680-1

USN-4680-1: Linux kernel vulnerabilities

Publication date

6 January 2021

Overview

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-oracle - Linux kernel for Oracle Cloud systems
  • linux-raspi2 - Linux kernel for Raspberry Pi (V8) systems
  • linux-snapdragon - Linux kernel for Qualcomm Snapdragon processors

Details

It was discovered that debugfs in the Linux kernel as used by blktrace
contained a use-after-free in some situations. A privileged local attacker
could possibly use this to cause a denial of service (system crash).
(CVE-2019-19770)

It was discovered that a race condition existed in the binder IPC
implementation in the Linux kernel, 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-2020-0423)

Daniele Antonioli, Nils Ole Tippenhauer, and Kasper Rasmussen discovered
that legacy pairing and secure-connections pairing authentication in the
Bluetooth protocol could allow an unauthenticated user to complete
authentication without pairing credentials via adjacent access. A
physically proximate attacker could use this to impersonate a...

It was discovered that debugfs in the Linux kernel as used by blktrace
contained a use-after-free in some situations. A privileged local attacker
could possibly use this to cause a denial of service (system crash).
(CVE-2019-19770)

It was discovered that a race condition existed in the binder IPC
implementation in the Linux kernel, 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-2020-0423)

Daniele Antonioli, Nils Ole Tippenhauer, and Kasper Rasmussen discovered
that legacy pairing and secure-connections pairing authentication in the
Bluetooth protocol could allow an unauthenticated user to complete
authentication without pairing credentials via adjacent access. A
physically proximate attacker could use this to impersonate a previously
paired Bluetooth device. (CVE-2020-10135)

It was discovered that the console keyboard driver in the Linux kernel
contained a race condition. A local attacker could use this to expose
sensitive information (kernel memory). (CVE-2020-25656)

Minh Yuan discovered that the tty driver in the Linux kernel contained race
conditions when handling fonts. A local attacker could possibly use this to
expose sensitive information (kernel memory). (CVE-2020-25668)

Keyu Man discovered that the ICMP global rate limiter in the Linux kernel
could be used to assist in scanning open UDP ports. A remote attacker could
use to facilitate attacks on UDP based services that depend on source port
randomization. (CVE-2020-25705)

Jinoh Kang discovered that the Xen event channel infrastructure in the
Linux kernel contained a race condition. An attacker in guest could
possibly use this to cause a denial of service (dom0 crash).
(CVE-2020-27675)

Daniel Axtens discovered that PowerPC RTAS implementation in the Linux
kernel did not properly restrict memory accesses in some situations. A
privileged local attacker could use this to arbitrarily modify kernel
memory, potentially bypassing kernel lockdown restrictions.
(CVE-2020-27777)

Minh Yuan discovered that the framebuffer console driver in the Linux
kernel did not properly handle fonts in some conditions. A local attacker
could use this to cause a denial of service (system crash) or possibly
expose sensitive information (kernel memory). (CVE-2020-28974)

Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

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.

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

Ubuntu Release Package Version
18.04 bionic linux-image-4.15.0-1062-oracle –  4.15.0-1062.68
linux-image-4.15.0-1077-gke –  4.15.0-1077.82
linux-image-4.15.0-1077-raspi2 –  4.15.0-1077.82
linux-image-4.15.0-1082-kvm –  4.15.0-1082.84
linux-image-4.15.0-1091-aws –  4.15.0-1091.96
linux-image-4.15.0-1091-gcp –  4.15.0-1091.104
linux-image-4.15.0-1094-snapdragon –  4.15.0-1094.103
linux-image-4.15.0-1103-azure –  4.15.0-1103.114
linux-image-4.15.0-129-generic –  4.15.0-129.132
linux-image-4.15.0-129-generic-lpae –  4.15.0-129.132
linux-image-4.15.0-129-lowlatency –  4.15.0-129.132
linux-image-aws-lts-18.04 –  4.15.0.1091.93
linux-image-azure-lts-18.04 –  4.15.0.1103.76
linux-image-gcp-lts-18.04 –  4.15.0.1091.109
linux-image-generic –  4.15.0.129.116
linux-image-generic-lpae –  4.15.0.129.116
linux-image-gke –  4.15.0.1077.81
linux-image-gke-4.15 –  4.15.0.1077.81
linux-image-kvm –  4.15.0.1082.78
linux-image-lowlatency –  4.15.0.129.116
linux-image-oracle-lts-18.04 –  4.15.0.1062.72
linux-image-raspi2 –  4.15.0.1077.74
linux-image-snapdragon –  4.15.0.1094.97
linux-image-virtual –  4.15.0.129.116
16.04 xenial linux-image-4.15.0-1062-oracle –  4.15.0-1062.68~16.04.1
linux-image-4.15.0-1091-aws –  4.15.0-1091.96~16.04.1
linux-image-4.15.0-1091-gcp –  4.15.0-1091.104~16.04.1
linux-image-4.15.0-1103-azure –  4.15.0-1103.114~16.04.1
linux-image-4.15.0-129-generic –  4.15.0-129.132~16.04.1
linux-image-4.15.0-129-generic-lpae –  4.15.0-129.132~16.04.1
linux-image-4.15.0-129-lowlatency –  4.15.0-129.132~16.04.1
linux-image-aws-hwe –  4.15.0.1091.85
linux-image-azure –  4.15.0.1103.96
linux-image-gcp –  4.15.0.1091.92
linux-image-generic-hwe-16.04 –  4.15.0.129.128
linux-image-generic-lpae-hwe-16.04 –  4.15.0.129.128
linux-image-gke –  4.15.0.1091.92
linux-image-lowlatency-hwe-16.04 –  4.15.0.129.128
linux-image-oem –  4.15.0.129.128
linux-image-oracle –  4.15.0.1062.51
linux-image-virtual-hwe-16.04 –  4.15.0.129.128
14.04 trusty linux-image-4.15.0-1103-azure –  4.15.0-1103.114~14.04.1
linux-image-azure –  4.15.0.1103.78

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References

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