=========================================================================
Ubuntu Security Notice USN-4890-1
March 25, 2021

linux, linux-aws, linux-aws-hwe, linux-azure, linux-azure-4.15,
linux-dell300x, linux-gcp, linux-gcp-4.15, linux-hwe, linux-kvm,
linux-oracle, linux-signed, linux-snapdragon vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-azure-4.15: Linux kernel for Microsoft Azure Cloud systems
- linux-dell300x: Linux kernel for Dell 300x platforms
- linux-gcp-4.15: Linux kernel for Google Cloud Platform (GCP) systems
- linux-kvm: Linux kernel for cloud environments
- linux-oracle: Linux kernel for Oracle Cloud systems
- linux-snapdragon: Linux kernel for Qualcomm Snapdragon processors
- linux-aws-hwe: Linux kernel for Amazon Web Services (AWS-HWE) systems
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-hwe: Linux hardware enablement (HWE) kernel

Details:

Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not
properly compute a speculative execution limit on pointer arithmetic in
some situations. A local attacker could use this to expose sensitive
information (kernel memory). (CVE-2020-27171)

Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not
properly apply speculative execution limits on some pointer types. A local
attacker could use this to expose sensitive information (kernel memory).
(CVE-2020-27170)

Update instructions:

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

Ubuntu 18.04 LTS:
  linux-image-4.15.0-1015-dell300x  4.15.0-1015.19
  linux-image-4.15.0-1068-oracle  4.15.0-1068.76
  linux-image-4.15.0-1088-kvm     4.15.0-1088.90
  linux-image-4.15.0-1096-gcp     4.15.0-1096.109
  linux-image-4.15.0-1097-aws     4.15.0-1097.104
  linux-image-4.15.0-1099-snapdragon  4.15.0-1099.108
  linux-image-4.15.0-1111-azure   4.15.0-1111.123
  linux-image-4.15.0-140-generic  4.15.0-140.144
  linux-image-4.15.0-140-generic-lpae  4.15.0-140.144
  linux-image-4.15.0-140-lowlatency  4.15.0-140.144
  linux-image-aws-lts-18.04       4.15.0.1097.100
  linux-image-azure-lts-18.04     4.15.0.1111.84
  linux-image-dell300x            4.15.0.1015.17
  linux-image-gcp-lts-18.04       4.15.0.1096.114
  linux-image-generic             4.15.0.140.127
  linux-image-generic-lpae        4.15.0.140.127
  linux-image-kvm                 4.15.0.1088.84
  linux-image-lowlatency          4.15.0.140.127
  linux-image-oracle-lts-18.04    4.15.0.1068.78
  linux-image-powerpc-e500mc      4.15.0.140.127
  linux-image-powerpc-smp         4.15.0.140.127
  linux-image-powerpc64-emb       4.15.0.140.127
  linux-image-powerpc64-smp       4.15.0.140.127
  linux-image-snapdragon          4.15.0.1099.102
  linux-image-virtual             4.15.0.140.127

Ubuntu 16.04 LTS:
  linux-image-4.15.0-1068-oracle  4.15.0-1068.76~16.04.1
  linux-image-4.15.0-1096-gcp     4.15.0-1096.109~16.04.1
  linux-image-4.15.0-1097-aws     4.15.0-1097.104~16.04.1
  linux-image-4.15.0-1111-azure   4.15.0-1111.123~16.04.1
  linux-image-4.15.0-140-generic  4.15.0-140.144~16.04.1
  linux-image-4.15.0-140-generic-lpae  4.15.0-140.144~16.04.1
  linux-image-4.15.0-140-lowlatency  4.15.0-140.144~16.04.1
  linux-image-aws-hwe             4.15.0.1097.90
  linux-image-azure               4.15.0.1111.102
  linux-image-gcp                 4.15.0.1096.97
  linux-image-generic-hwe-16.04   4.15.0.140.135
  linux-image-generic-lpae-hwe-16.04  4.15.0.140.135
  linux-image-gke                 4.15.0.1096.97
  linux-image-lowlatency-hwe-16.04  4.15.0.140.135
  linux-image-oem                 4.15.0.140.135
  linux-image-oracle              4.15.0.1068.56
  linux-image-virtual-hwe-16.04   4.15.0.140.135

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.

References:
  https://ubuntu.com/security/notices/USN-4890-1
  CVE-2020-27170, CVE-2020-27171

Package Information:
  https://launchpad.net/ubuntu/+source/linux/4.15.0-140.144
  https://launchpad.net/ubuntu/+source/linux-aws/4.15.0-1097.104
  https://launchpad.net/ubuntu/+source/linux-azure-4.15/4.15.0-1111.123
  https://launchpad.net/ubuntu/+source/linux-dell300x/4.15.0-1015.19
  https://launchpad.net/ubuntu/+source/linux-gcp-4.15/4.15.0-1096.109
  https://launchpad.net/ubuntu/+source/linux-kvm/4.15.0-1088.90
  https://launchpad.net/ubuntu/+source/linux-oracle/4.15.0-1068.76
  https://launchpad.net/ubuntu/+source/linux-snapdragon/4.15.0-1099.108
  https://launchpad.net/ubuntu/+source/linux-aws-hwe/4.15.0-1097.104~16.04.1
  https://launchpad.net/ubuntu/+source/linux-azure/4.15.0-1111.123~16.04.1
  https://launchpad.net/ubuntu/+source/linux-gcp/4.15.0-1096.109~16.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe/4.15.0-140.144~16.04.1
  https://launchpad.net/ubuntu/+source/linux-oracle/4.15.0-1068.76~16.04.1