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USN-4950-1: Linux kernel vulnerabilities

11 May 2021

Several security issues were fixed in the Linux kernel.

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Releases

Packages

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-kvm - Linux kernel for cloud environments
  • linux-oracle - Linux kernel for Oracle Cloud systems
  • linux-raspi - Linux kernel for Raspberry Pi (V8) systems

Details

Ryota Shiga discovered that the eBPF implementation in the Linux kernel did
not properly verify that a BPF program only reserved as much memory for a
ring buffer as was allocated. A local attacker could use this to cause a
denial of service (system crash) or execute arbitrary code. (CVE-2021-3489)

Manfred Paul discovered that the eBPF implementation in the Linux kernel
did not properly track bounds on bitwise operations. A local attacker could
use this to cause a denial of service (system crash) or execute arbitrary
code. (CVE-2021-3490)

Billy Jheng Bing-Jhong discovered that the io_uring implementation of the
Linux kernel did not properly enforce the MAX_RW_COUNT limit in some
situations. A local attacker could use this to cause a denial of service
(system crash) or execute arbitrary code. (CVE-2021-3491)

Norbert Slusarek discovered that the CAN ISOTP protocol implementation
in the Linux kernel contained a race condition. A local attacker could
use this to cause a denial of service (system crash) or possibly
execute arbitrary code. Please note that to address this issue,
SF_BROADCAST support was removed temporarily from the CAN ISOTP
implementation in Ubuntu 21.04 kernels. (LP: #1927409)

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 21.04

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-4948-1: linux-image-oem-20.04-edge, linux-image-oem-20.04b, linux-image-5.10.0-1026-oem, linux-oem-5.10
  • USN-4949-1: linux-image-kvm, linux-image-gcp, linux-image-generic-lpae-hwe-20.04-edge, linux-image-5.8.0-1024-raspi, linux-image-oem-20.04, linux-image-generic-64k, linux-image-generic-64k-hwe-20.04-edge, linux-kvm, linux-hwe-5.8, linux-image-lowlatency-hwe-20.04-edge, linux-image-5.8.0-1032-azure, linux-image-azure, linux-image-generic-hwe-20.04-edge, linux-image-5.8.0-53-lowlatency, linux-image-generic, linux-azure, linux-image-5.8.0-53-generic-64k, linux-image-generic-hwe-20.04, linux-image-raspi, linux-image-5.8.0-53-generic, linux-image-5.8.0-53-generic-lpae, linux-image-lowlatency-hwe-20.04, linux-aws, linux-image-virtual-hwe-20.04, linux-image-gke, linux-image-5.8.0-1033-aws, linux-image-generic-lpae, linux-image-lowlatency, linux, linux-image-5.8.0-1029-oracle, linux-image-generic-lpae-hwe-20.04, linux-image-virtual, linux-image-5.8.0-1027-kvm, linux-image-generic-64k-hwe-20.04, linux-gcp, linux-image-oracle, linux-image-aws, linux-image-raspi-nolpae, linux-raspi, linux-image-5.8.0-1024-raspi-nolpae, linux-image-5.8.0-1031-gcp, linux-image-virtual-hwe-20.04-edge, linux-oracle