USN-4910-1: Linux kernel vulnerabilities

13 April 2021

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-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - 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-raspi - Linux kernel for Raspberry Pi (V8) systems

Details

Ryota Shiga discovered that the sockopt BPF hooks in the Linux kernel could
allow a user space program to probe for valid kernel addresses. A local
attacker could use this to ease exploitation of another kernel
vulnerability. (CVE-2021-20239)

It was discovered that the BPF verifier in the Linux kernel did not
properly handle signed add32 and sub integer overflows. A local attacker
could use this to cause a denial of service (system crash) or possibly
execute arbitrary code. (CVE-2021-20268)

It was discovered that the priority inheritance futex implementation in the
Linux kernel contained a race condition, 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-2021-3347)

It was discovered that the network block device (nbd) driver in the Linux
kernel contained a use-after-free vulnerability during device setup. A
local attacker with access to the nbd device could use this to cause a
denial of service (system crash) or possibly execute arbitrary code.
(CVE-2021-3348)

吴异 discovered that the NFS implementation in the Linux kernel did not
properly prevent access outside of an NFS export that is a subdirectory of
a file system. An attacker could possibly use this to bypass NFS access
restrictions. (CVE-2021-3178)

Update instructions

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

Ubuntu 20.10
Ubuntu 20.04

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-4877-1: linux-gcp-4.15, linux-image-4.15.0-1094-gcp, linux-image-raspi2, linux-snapdragon, linux-image-4.15.0-1086-kvm, linux-image-oracle, linux-image-azure-edge, linux-image-4.15.0-137-lowlatency, linux-aws, linux-image-4.15.0-1080-raspi2, linux-image-generic-lpae, linux-raspi2, linux-image-virtual-hwe-16.04, linux-gcp, linux-image-gcp-lts-18.04, linux-image-lowlatency-hwe-16.04, linux-azure-4.15, linux-image-virtual, linux-azure, linux-image-4.15.0-1066-oracle, linux-kvm, linux-image-generic-lpae-hwe-16.04, linux-aws-hwe, linux-image-4.15.0-1097-snapdragon, linux-image-4.15.0-1013-dell300x, linux-image-4.15.0-137-generic, linux-image-azure, linux-oracle, linux-image-oracle-lts-18.04, linux-image-4.15.0-1095-aws, linux-image-virtual-hwe-16.04-edge, linux-image-generic, linux-image-generic-hwe-16.04-edge, linux-image-dell300x, linux, linux-image-lowlatency, linux-dell300x, linux-image-4.15.0-137-generic-lpae, linux-image-aws-hwe, linux-image-4.15.0-1109-azure, linux-image-aws-lts-18.04, linux-image-azure-lts-18.04, linux-hwe, linux-image-gke, linux-image-snapdragon, linux-image-kvm, linux-image-lowlatency-hwe-16.04-edge, linux-image-generic-lpae-hwe-16.04-edge, linux-image-gcp, linux-image-oem, linux-image-generic-hwe-16.04
  • USN-4912-1: linux-image-oem-20.04, linux-image-5.6.0-1053-oem, linux-oem-5.6
  • USN-4907-1: linux-gcp-4.15, linux-image-raspi2, linux-snapdragon, linux-image-oracle, linux-image-4.15.0-1089-kvm, linux-image-4.15.0-141-generic, linux-image-azure-edge, linux-image-4.15.0-1097-gcp, linux-aws, linux-image-4.15.0-1098-aws, linux-image-generic-lpae, linux-raspi2, linux-image-virtual-hwe-16.04, linux-gcp, linux-image-4.15.0-1083-raspi2, linux-image-4.15.0-1112-azure, linux-azure-4.15, linux-image-gcp-lts-18.04, linux-image-lowlatency-hwe-16.04, linux-azure, linux-image-virtual, linux-image-4.15.0-1069-oracle, linux-image-generic-lpae-hwe-16.04, linux-kvm, linux-aws-hwe, linux-image-azure, linux-image-4.15.0-1016-dell300x, linux-oracle, linux-image-oracle-lts-18.04, linux-image-virtual-hwe-16.04-edge, linux-image-generic, linux-image-generic-hwe-16.04-edge, linux-image-4.15.0-141-generic-lpae, linux-image-dell300x, linux, linux-image-4.15.0-141-lowlatency, linux-dell300x, linux-image-lowlatency, linux-image-aws-hwe, linux-image-aws-lts-18.04, linux-image-azure-lts-18.04, linux-image-gke, linux-image-snapdragon, linux-image-kvm, linux-image-lowlatency-hwe-16.04-edge, linux-image-4.15.0-1100-snapdragon, linux-image-generic-lpae-hwe-16.04-edge, linux-image-gcp, linux-image-generic-hwe-16.04
  • USN-4878-1: linux-image-5.4.0-1030-raspi, linux-azure-5.4, linux-aws-5.4, linux-image-generic-hwe-18.04, linux-image-gke-5.4, linux-image-raspi2, linux-image-gkeop, linux-image-virtual-hwe-18.04-edge, linux-gkeop, linux-image-oracle, linux-image-5.4.0-1041-azure, linux-image-5.4.0-1037-gke, linux-image-lowlatency-hwe-18.04-edge, linux-gke-5.4, linux-image-azure-edge, linux-image-generic-lpae-hwe-18.04-edge, linux-gkeop-5.4, linux-image-5.4.0-1039-aws, linux-image-oracle-edge, linux-image-aws-edge, linux-aws, linux-image-raspi2-hwe-18.04-edge, linux-image-generic-lpae, linux-image-generic-hwe-18.04-edge, linux-image-5.4.0-67-generic, linux-image-generic-lpae-hwe-18.04, linux-image-raspi, linux-image-5.4.0-1038-gcp, linux-hwe-5.4, linux-gcp, linux-image-5.4.0-1011-gkeop, linux-image-virtual, linux-image-virtual-hwe-18.04, linux-image-5.4.0-1039-oracle, linux-azure, linux-kvm, linux-gcp-5.4, linux-image-snapdragon-hwe-18.04-edge, linux-image-5.4.0-67-generic-lpae, linux-image-azure, linux-image-gkeop-5.4, linux-image-5.4.0-1034-kvm, linux-image-raspi-hwe-18.04, linux-image-raspi-hwe-18.04-edge, linux-image-snapdragon-hwe-18.04, linux-oracle, linux-image-generic, linux-image-5.4.0-67-lowlatency, linux-image-lowlatency, linux, linux-image-oem-osp1, linux-image-aws, linux-image-kvm, linux-oracle-5.4, linux-image-raspi2-hwe-18.04, linux-raspi-5.4, linux-image-lowlatency-hwe-18.04, linux-image-gcp-edge, linux-image-gcp, linux-image-oem, linux-raspi
  • USN-4909-1: linux-image-generic-hwe-18.04, linux-azure-5.4, linux-aws-5.4, linux-image-5.4.0-1037-kvm, linux-image-gke-5.4, linux-image-raspi2, linux-image-5.4.0-1040-gke, linux-image-5.4.0-1042-oracle, linux-image-gkeop, linux-image-gcp, linux-image-virtual-hwe-18.04-edge, linux-gkeop, linux-image-5.4.0-1044-azure, linux-image-oracle, linux-image-5.4.0-1033-raspi, linux-image-lowlatency-hwe-18.04-edge, linux-gke-5.4, linux-image-azure-edge, linux-image-generic-lpae-hwe-18.04-edge, linux-image-5.4.0-71-lowlatency, linux-gkeop-5.4, linux-image-oracle-edge, linux-image-5.4.0-1041-gcp, linux-image-aws-edge, linux-aws, linux-image-raspi2-hwe-18.04-edge, linux-image-generic-lpae, linux-image-5.4.0-1013-gkeop, linux-image-generic-hwe-18.04-edge, linux-image-5.4.0-71-generic-lpae, linux-image-generic-lpae-hwe-18.04, linux-image-raspi, linux-hwe-5.4, linux-gcp, linux-image-virtual, linux-image-virtual-hwe-18.04, linux-azure, linux-kvm, linux-gcp-5.4, linux-image-snapdragon-hwe-18.04-edge, linux-image-azure, linux-image-gkeop-5.4, linux-image-raspi-hwe-18.04, linux-image-raspi-hwe-18.04-edge, linux-image-snapdragon-hwe-18.04, linux-oracle, linux-image-generic, linux-image-lowlatency, linux, linux-image-oem-osp1, linux-image-aws, linux-image-5.4.0-1043-aws, linux-image-kvm, linux-oracle-5.4, linux-image-raspi2-hwe-18.04, linux-raspi-5.4, linux-image-lowlatency-hwe-18.04, linux-image-gcp-edge, linux-image-5.4.0-71-generic, linux-image-oem, linux-raspi
  • USN-4884-1: linux-image-oem-20.04b, linux-oem-5.10, linux-image-5.10.0-1017-oem, linux-image-oem-20.04-edge
  • USN-4876-1: linux-image-raspi2, linux-image-powerpc64-emb-lts-utopic, linux-snapdragon, linux-image-4.4.0-1123-aws, linux-image-powerpc64-smp, linux-image-powerpc-smp-lts-xenial, linux-image-generic-lpae-lts-vivid, linux-image-4.4.0-1147-raspi2, linux-image-powerpc-e500mc-lts-wily, linux-image-4.4.0-204-generic, linux-image-powerpc64-smp-lts-vivid, linux-image-lowlatency-lts-vivid, linux-image-4.4.0-1089-kvm, linux-aws, linux-image-4.4.0-204-powerpc64-emb, linux-image-generic-lpae-lts-utopic, linux-image-lowlatency-lts-utopic, linux-image-4.4.0-1151-snapdragon, linux-image-lowlatency-lts-wily, linux-image-generic-lts-xenial, linux-image-powerpc64-emb-lts-vivid, linux-raspi2, linux-image-virtual, linux-image-virtual-lts-vivid, linux-image-powerpc-e500mc-lts-xenial, linux-image-powerpc-smp, linux-lts-xenial, linux-image-generic-lts-wily, linux-image-lowlatency-lts-xenial, linux-kvm, linux-image-virtual-lts-wily, linux-image-powerpc64-smp-lts-xenial, linux-image-virtual-lts-utopic, linux-image-powerpc-e500mc, linux-image-generic-lts-utopic, linux-image-powerpc64-smp-lts-utopic, linux-image-4.4.0-204-powerpc-e500mc, linux-image-4.4.0-204-powerpc-smp, linux-image-generic, linux-image-generic-lts-vivid, linux-image-powerpc64-emb-lts-wily, linux-image-powerpc64-emb-lts-xenial, linux-image-lowlatency, linux, linux-image-powerpc-e500mc-lts-vivid, linux-image-4.4.0-204-powerpc64-smp, linux-image-4.4.0-204-generic-lpae, linux-image-aws, linux-image-powerpc-smp-lts-wily, linux-image-4.4.0-204-lowlatency, linux-image-powerpc64-emb, linux-image-snapdragon, linux-image-kvm, linux-image-powerpc-smp-lts-vivid, linux-image-powerpc64-smp-lts-wily, linux-image-powerpc-e500mc-lts-utopic, linux-image-virtual-lts-xenial, linux-image-4.4.0-1087-aws, linux-image-generic-lpae, linux-image-generic-lpae-lts-wily, linux-image-powerpc-smp-lts-utopic, linux-image-generic-lpae-lts-xenial