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=== What kinds of updates are not provided by the Livepatch service? === In general, the livepatch service provides patches exclusively for security issues that have been assigned a CVE and are rated as a medium security issue or higher. Livepatches are intended to address significant security issues in the kernel, and provide customers with protection from serious vulnerabilities until they can schedule a reboot. All CVEs that are rated as either a high or critical issue will always be livepatched if possible, and, if it is not possible, a notification that a reboot is required will be issued by the Livepatch client. In addition, some medium severity CVEs will be patched when possible. There are frequently patches included in [[https://wiki.ubuntu.com/KernelTeam/KernelUpdates|kernel updates]] that are not included in the Livepatch service, such as: * bug fixes that are not security issues * performance improvements * driver updates * new features To receive these updates, it is necessary to upgrade the kernel package using the package manager for the system (apt for Ubuntu desktop or server, or snapd if running on Ubuntu Core) and then reboot into the upgraded kernel. |
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.
System Requirements
Ubuntu release |
Arch |
Kernel Version |
Kernel Variants |
Ubuntu 20.04 LTS |
64-bit x86 |
5.4 (GA) |
generic, lowlatency, aws, azure, oem |
Ubuntu 18.04 LTS |
64-bit x86 |
5.4 (HWE) |
generic, lowlatency |
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.
Livepatches are released at the same time as each kernel SRU, and contain a subset of the CVEs fixed by that kernel SRU. Livepatches are cumulative, so when a new livepatch is released, it contains both the new CVE fixes, as well as all of the CVE fixes from the previous release of that livepatch.
What kinds of updates are not provided by the Livepatch service?
In general, the livepatch service provides patches exclusively for security issues that have been assigned a CVE and are rated as a medium security issue or higher.
Livepatches are intended to address significant security issues in the kernel, and provide customers with protection from serious vulnerabilities until they can schedule a reboot. All CVEs that are rated as either a high or critical issue will always be livepatched if possible, and, if it is not possible, a notification that a reboot is required will be issued by the Livepatch client. In addition, some medium severity CVEs will be patched when possible.
There are frequently patches included in kernel updates that are not included in the Livepatch service, such as:
- bug fixes that are not security issues
- performance improvements
- driver updates
- new features
To receive these updates, it is necessary to upgrade the kernel package using the package manager for the system (apt for Ubuntu desktop or server, or snapd if running on Ubuntu Core) and then reboot into the upgraded kernel.
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)