Livepatch

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|| Ubuntu 20.04 LTS || 64-bit x86 || 5.4 (GA) || generic, lowlatency, aws, azure ||

Kernel Livepatch

This is a collection of notes and FAQs for the Canonical Livepatch Service. That page has a general introduction, data sheet and the ability to sign up for the service.

https://snapcraft.io/canonical-livepatch

System Requirements

Ubuntu release

Arch

Kernel Version

Kernel Variants

Ubuntu 20.04 LTS

64-bit x86

5.4 (GA)

generic, lowlatency, aws, azure

Ubuntu 18.04 LTS

64-bit x86

5.0 (HWE)

azure only rolling HWE kernel

Ubuntu 18.04 LTS

64-bit x86

4.15 (GA)

generic, lowlatency, aws, oem

Ubuntu 16.04 LTS

64-bit x86

4.15 (HWE)

generic, lowlatency, azure

Ubuntu 16.04 LTS

64-bit x86

4.4 (GA)

generic, lowlatency, aws

Ubuntu 14.04 ESM

64-bit x86

4.4 (HWE)

generic, lowlatency

GA is the kernel a release launched with while HWE or Hardware Enablement is what has been added per that process. A rolling HWE kernel means that it will require major kernel upgrades per that LTS's specific plan.

Additionally, network access to the Canonical Livepatch Service (https://livepatch.canonical.com:443) and the latest version of snapd (at least 2.15) are needed.

Security Notices

Livepatch Security Notices (LSN) are only available by subscribing to the Ubuntu Security Announcements mailing list. LSNs will be released for:

  • Announcing a new livepatch.
  • An alert if a livepatch cannot be released describing why and possible mitigation notes.
    • a standard Ubuntu security notice (USN) will be released with packages along side it to fix the issue.

    • the livepatch client will start issuing a warning that an update and reboot is necessary.

NOTE You must subscribe to the mailing list. The USN RSS Feed, CVE tracker, and other services do not know about Livepatch Security Notices.

FAQ

What kinds of updates will be provided by the Canonical Livepatch Service?

The Livepatch Service intends to address high and critical severity Linux kernel security vulnerabilities, as identified by Ubuntu Security Notices and the CVE tracker. Since there are limitations to the kernel livepatch technology, some Linux kernel code paths cannot be safely patched while running. There may be occasions when the traditional kernel upgrade and reboot might still be necessary.

How do you rate a CVE?

We do not use an external rating system, but rate based on these qualifications:

negligible

Something that is technically a security problem, but is only theoretical in nature, requires a very special situation, has almost no install base, or does no real damage. These tend not to get backport from upstreams, and will likely not be included in security updates unless there is an easy fix and some other issue causes an update.

low

Something that is a security problem, but is hard to exploit due to environment, requires a user-assisted attack, a small install base, or does very little damage. These tend to be included in security updates only when higher priority issues require an update, or if many low priority issues have built up.

medium

Something is a real security problem, and is exploitable for many people. Includes network daemon denial of service attacks, cross-site scripting, and gaining user privileges. Updates should be made soon for this priority of issue.

high

A real problem, exploitable for many people in a default installation. Includes serious remote denial of services, local root privilege escalations, or data loss.

critical

A world-burning problem, exploitable for nearly all people in a default installation of Ubuntu. Includes remote root privilege escalations, or massive data loss.

What happens when a problem occurs that can't be patched?

When an un-patchable security issue occurs, users must upgrade to a version of the kernel that is fixed, and reboot. Problems of this type are announced on the mailing list via LSN. Kernels prior to the levels named in that announcement will no longer be livepatched.

The Livepatch client will report a state of "kernel-upgrade-required" if you are running a kernel that is no longer livepatched due to an earlier un-patchable kernel security issue.

Why isn't Livepatch working on my machine?

SECUREBOOT

If you are using secure boot, you will also need to import the livepatch public keys into your keyring.

This can be done with the following command:

sudo mokutil --import /snap/canonical-livepatch/current/keys/livepatch-kmod.x509

After this enter a password if necessary for MOK, then reboot. Your BIOS will then guide you through enrolling a new key in MOK. At this point you will be able to verify the module signatures.

How do I get more help?

For support questions see: https://www.ubuntu.com/management/ubuntu-advantage

Ubuntu Advantage customers may file support tickets at: https://support.canonical.com

Bugs

Please file bugs using the following URL: https://bugs.launchpad.net/canonical-livepatch-client/+filebug

When you open a bug, please provide the output from the following commands, so that we can troubleshoot your issue:

  • snap info canonical-livepatch
  • canonical-livepatch status
  • lsb_release -a
  • uname -a
  • journalctl -u snap.canonical-livepatch.canonical-livepatchd (this can be long, so maybe | tail -100 for recent issues)

Recommend marking the bug as private if any of the above contains personal information that you do not want publicly available and searchable.

Kernel/Livepatch (last edited 2021-10-21 19:14:00 by nmavrogiannopoulos)