Skip to main content

Ubuntu Livepatch service now supports over 60 different kernels

Linux kernel getting a livepatch whilst running a marathon. Generated with AI.

Livepatch service eliminates the need for unplanned maintenance windows for high and critical severity kernel vulnerabilities by patching the Linux kernel while the system runs. Originally the service launched in 2016 with just a single kernel flavour supported.

Over the years, additional kernels were added: new LTS releases, ESM kernels, Public Cloud kernels, and most recently HWE kernels too.

Recently livepatch support was expanded for FIPS compliant kernels, Public cloud FIPS compliant kernels, and as well IBM Z (mainframe) kernels. Bringing the total of kernel flavours support to over 60 distinct kernel flavours supported in parallel. The table of supported kernels in the documentation lists the supported kernel flavours ABIs, the duration of individual build's support window, supported architectures, and the Ubuntu release. This work was only possible thanks to the collaboration with the Ubuntu Certified Public Cloud team, engineers at IBM for IBM Z (s390x) support, Ubuntu Pro team, Livepatch server & client teams.

It is a great milestone, and I personally enjoy seeing the non-intrusive popup on my Ubuntu Desktop that a kernel livepatch was applied to my running system. I do enable Ubuntu Pro on my personal laptop thanks to the free Ubuntu Pro subscription for individuals.

What's next? The next frontier is supporting ARM64 kernels. The Canonical kernel team has completed the gap analysis to start supporting Livepatch Service for ARM64. Upstream Linux requires development work on the consistency model to fully support livepatch on ARM64 processors. Livepatch code changes are applied on a per-task basis, when the task is deemed safe to switch over. This safety check depends mostly on kernel stacktraces. For these checks, CONFIG_HAVE_RELIABLE_STACKTRACE needs to be available in the upstream ARM64 kernel. (see The Linux Kernel Documentation). There are preliminary patches that enable reliable stacktraces on ARM64, however these turned out to be problematic as there are lots of fix revisions that came after the initial patchset that AWS ships with 5.10. This is a call for help from any interested parties. If you have engineering resources and are interested in bringing Livepatch Service to your ARM64 platforms, please reach out to the Canonical Kernel team on the public Ubuntu Matrix, Discourse, and mailing list. If you want to chat in person, see you at FOSDEM next weekend.

Labels:

Comments

Post a Comment

Popular posts from this blog

How to disable TLS 1.0 and TLS 1.1 on Ubuntu

Example of website that only supports TLS v1.0, which is rejected by the client Overivew TLS v1.3 is the latest standard for secure communication over the internet. It is widely supported by desktops, servers and mobile phones. Recently Ubuntu 18.04 LTS received OpenSSL 1.1.1 update bringing the ability to potentially establish TLS v1.3 connections on the latest Ubuntu LTS release. Qualys SSL Labs Pulse report shows more than 15% adoption of TLS v1.3. It really is time to migrate from TLS v1.0 and TLS v1.1. As announced on the 15th of October 2018 Apple , Google , and Microsoft will disable TLS v1.0 and TLS v1.1 support by default and thus require TLS v1.2 to be supported by all clients and servers. Similarly, Ubuntu 20.04 LTS will also require TLS v1.2 as the minimum TLS version as well. To prepare for the move to TLS v1.2, it is a good idea to disable TLS v1.0 and TLS v1.1 on your local systems and start observing and reporting any websites, systems and applications that...
6 comments
Read more

Ubuntu 23.10 significantly reduces the installed kernel footprint

Photo by Pixabay Ubuntu systems typically have up to 3 kernels installed, before they are auto-removed by apt on classic installs. Historically the installation was optimized for metered download size only. However, kernel size growth and usage no longer warrant such optimizations. During the 23.10 Mantic Minatour cycle, I led a coordinated effort across multiple teams to implement lots of optimizations that together achieved unprecedented install footprint improvements. Given a typical install of 3 generic kernel ABIs in the default configuration on a regular-sized VM (2 CPU cores 8GB of RAM) the following metrics are achieved in Ubuntu 23.10 versus Ubuntu 22.04 LTS: 2x less disk space used (1,417MB vs 2,940MB, including initrd) 3x less peak RAM usage for the initrd boot (68MB vs 204MB) 0.5x increase in download size (949MB vs 600MB) 2.5x faster initrd generation (4.5s vs 11.3s) approximately the same total time (103s vs 98s, hardware dependent) For minimal cloud images that do not in...
Read more