1. Ubuntu Security Notices
  2. USN-4999-1

USN-4999-1: Linux kernel vulnerabilities

Publication date

23 June 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-5.8 - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-azure-5.8 - Linux kernel for Microsoft Azure cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-gcp-5.8 - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-hwe-5.8 - Linux hardware enablement (HWE) kernel
  • linux-kvm - Linux kernel for cloud environments
  • linux-oracle - Linux kernel for Oracle Cloud systems
  • linux-oracle-5.8 - Linux kernel for Oracle Cloud systems
  • linux-raspi - Linux kernel for Raspberry Pi (V8) systems

Details

Norbert Slusarek discovered a race condition in the CAN BCM networking
protocol of the Linux kernel leading to multiple use-after-free
vulnerabilities. A local attacker could use this issue to execute arbitrary
code. (CVE-2021-3609)

Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel
did not properly enforce limits for pointer operations. A local attacker
could use this to cause a denial of service (system crash) or possibly
execute arbitrary code. (CVE-2021-33200)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation did
not properly clear received fragments from memory in some situations. A
physically proximate attacker could possibly use this issue to inject
packets or expose sensitive information. (CVE-2020-24586)

Mathy Vanhoef discovered that the Linux kernel’s WiFi...

Norbert Slusarek discovered a race condition in the CAN BCM networking
protocol of the Linux kernel leading to multiple use-after-free
vulnerabilities. A local attacker could use this issue to execute arbitrary
code. (CVE-2021-3609)

Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel
did not properly enforce limits for pointer operations. A local attacker
could use this to cause a denial of service (system crash) or possibly
execute arbitrary code. (CVE-2021-33200)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation did
not properly clear received fragments from memory in some situations. A
physically proximate attacker could possibly use this issue to inject
packets or expose sensitive information. (CVE-2020-24586)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation
incorrectly handled encrypted fragments. A physically proximate attacker
could possibly use this issue to decrypt fragments. (CVE-2020-24587)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation
incorrectly handled certain malformed frames. If a user were tricked into
connecting to a malicious server, a physically proximate attacker could use
this issue to inject packets. (CVE-2020-24588)

Kiyin (尹亮) discovered that the NFC LLCP protocol implementation in the
Linux kernel contained a reference counting error. A local attacker could
use this to cause a denial of service (system crash). (CVE-2020-25670)

Kiyin (尹亮) discovered that the NFC LLCP protocol implementation in the
Linux kernel did not properly deallocate memory in certain error
situations. A local attacker could use this to cause a denial of service
(memory exhaustion). (CVE-2020-25671, CVE-2020-25672)

Kiyin (尹亮) discovered that the NFC LLCP protocol implementation in the
Linux kernel did not properly handle error conditions in some situations,
leading to an infinite loop. A local attacker could use this to cause a
denial of service. (CVE-2020-25673)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation
incorrectly handled EAPOL frames from unauthenticated senders. A physically
proximate attacker could inject malicious packets to cause a denial of
service (system crash). (CVE-2020-26139)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation did
not properly verify certain fragmented frames. A physically proximate
attacker could possibly use this issue to inject or decrypt packets.
(CVE-2020-26141)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation
accepted plaintext fragments in certain situations. A physically proximate
attacker could use this issue to inject packets. (CVE-2020-26145)

Mathy Vanhoef discovered that the Linux kernel’s WiFi implementation could
reassemble mixed encrypted and plaintext fragments. A physically proximate
attacker could possibly use this issue to inject packets or exfiltrate
selected fragments. (CVE-2020-26147)

Or Cohen discovered that the SCTP implementation in the Linux kernel
contained a race condition in some situations, leading to a use-after-free
condition. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2021-23133)

Piotr Krysiuk and Benedict Schlueter discovered that the eBPF
implementation in the Linux kernel performed out of bounds speculation on
pointer arithmetic. A local attacker could use this to expose sensitive
information. (CVE-2021-29155)

Manfred Paul discovered that the extended Berkeley Packet Filter (eBPF)
implementation in the Linux kernel contained an out-of-bounds
vulnerability. A local attacker could use this issue to execute arbitrary
code. (CVE-2021-31440)

Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel
did not properly prevent speculative loads in certain situations. A local
attacker could use this to expose sensitive information (kernel memory).
(CVE-2021-31829)

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
20.10 groovy linux-image-5.8.0-59-lowlatency –  5.8.0-59.66
linux-image-5.8.0-1029-raspi –  5.8.0-1029.32
linux-image-5.8.0-1038-aws –  5.8.0-1038.40
linux-image-oracle –  5.8.0.1033.32
linux-image-azure –  5.8.0.1036.36
linux-image-raspi-nolpae –  5.8.0.1029.31
linux-image-5.8.0-59-generic-64k –  5.8.0-59.66
linux-image-5.8.0-59-generic-lpae –  5.8.0-59.66
linux-image-virtual –  5.8.0.59.64
linux-image-raspi –  5.8.0.1029.31
linux-image-gke –  5.8.0.1035.35
linux-image-generic-64k –  5.8.0.59.64
linux-image-generic –  5.8.0.59.64
linux-image-5.8.0-1036-azure –  5.8.0-1036.38
linux-image-5.8.0-1033-oracle –  5.8.0-1033.34
linux-image-aws –  5.8.0.1038.40
linux-image-kvm –  5.8.0.1030.32
linux-image-5.8.0-1030-kvm –  5.8.0-1030.32
linux-image-generic-lpae –  5.8.0.59.64
linux-image-gcp –  5.8.0.1035.35
linux-image-5.8.0-1029-raspi-nolpae –  5.8.0-1029.32
linux-image-5.8.0-1035-gcp –  5.8.0-1035.37
linux-image-5.8.0-59-generic –  5.8.0-59.66
linux-image-lowlatency –  5.8.0.59.64
20.04 focal linux-image-virtual-hwe-20.04 –  5.8.0.59.66~20.04.42
linux-image-5.8.0-59-generic-64k –  5.8.0-59.66~20.04.1
linux-image-5.8.0-59-lowlatency –  5.8.0-59.66~20.04.1
linux-image-generic-lpae-hwe-20.04 –  5.8.0.59.66~20.04.42
linux-image-5.8.0-59-generic –  5.8.0-59.66~20.04.1
linux-image-gcp –  5.8.0.1035.37~20.04.9
linux-image-generic-64k-hwe-20.04 –  5.8.0.59.66~20.04.42
linux-image-5.8.0-1036-azure –  5.8.0-1036.38~20.04.1
linux-image-5.8.0-1033-oracle –  5.8.0-1033.34~20.04.1
linux-image-lowlatency-hwe-20.04 –  5.8.0.59.66~20.04.42
linux-image-5.8.0-1035-gcp –  5.8.0-1035.37~20.04.1
linux-image-aws –  5.8.0.1038.40~20.04.11
linux-image-generic-hwe-20.04 –  5.8.0.59.66~20.04.42
linux-image-5.8.0-1038-aws –  5.8.0-1038.40~20.04.1
linux-image-5.8.0-59-generic-lpae –  5.8.0-59.66~20.04.1
linux-image-oracle –  5.8.0.1033.34~20.04.9
linux-image-azure –  5.8.0.1036.38~20.04.8

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References

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