The Internet Engineering Task Force (IETF) is the standards body responsible for the TLS encryption standard — which your browser is using right now to allow you to read LWN.net. As part of its work to keep TLS secure, the IETF has been entertaining proposals to adopt "post-quantum" cryptography (that is, cryptography that is not known to be easily broken by a quantum computer) for TLS version 1.3. Discussion of the proposal has exposed a large disagreement between participants who worried about weakened security and others who worried about weakened marketability.

Jon Seager, VP of engineering for Canonical, has announced a plan to develop a universal Public Key Infrastructure tool called upki:

Earlier this year, LWN featured an excellent article titled "Linux's missing CRL infrastructure". The article highlighted a number of key issues surrounding traditional Public Key Infrastructure (PKI), but critically noted how even the available measures are effectively ignored by the majority of system-level software on Linux.

One of the motivators for the discussion is that the Online Certificate Status Protocol (OCSP) will cease to be supported by Let's Encrypt. The remaining alternative is to use Certificate Revocation Lists (CRLs), yet there is little or no support for managing (or even querying) these lists in most Linux system utilities.

To solve this, I'm happy to share that in partnership with rustls maintainers Dirkjan Ochtman and Joe Birr-Pixton, we're starting the development of upki: a universal PKI tool. This project initially aims to close the revocation gap through the combination of a new system utility and eventual library support for common TLS/SSL libraries such as OpenSSL, GnuTLS and rustls.

No code is available as of yet, but the announcement indicates that upki will be available as an opt-in preview for Ubuntu 26.04 LTS. Thanks to Dirjan Ochtman for the tip.

Greg Kroah-Hartman has announced the release of the 6.17.11, 6.12.61, 6.6.119, 6.1.159, 5.15.197, and 5.10.247 stable kernels. Each contains important fixes throughout the tree; users of these kernels should upgrade.

Emma Smith and Kirill Podoprigora, two of Python's core developers, have opened a discussion about including Rust code in CPython, the reference implementation of the Python programming language. Initially, Rust would only be used for optional extension modules, but they would like to see Rust become a required dependency over time. The initial plan was to make Rust required by 2028, but Smith and Podoprigora indefinitely postponed that goal in response to concerns raised in the discussion.

Version 3.23.0 of Alpine Linux has been released. Notable changes in this release include an upgrade to version 3.0 of the Alpine Package Keeper (apk), and replacing the linux-edge package with linux-stable:

For years, linux-lts and linux-edge grew apart and developed their own kernel configs, different architectures, etc.

Now linux-edge gets replaced with linux-stable which has the identical configuration as linux-lts, but follows the stable releases instead of the long-term releases (see https://kernel.org/).

The /usr merge planned for this release has been postponed; a new timeline for the change will be published later. See the release notes for more information on this release.

Andreas Schneider has announced version 2.0 of the cmocka unit-testing framework for C:

This release represents a major modernization effort, bringing cmocka firmly into the "modern" C99 era while maintaining the simplicity and ease of use that users have come to expect.

One of the most significant changes in cmocka 2.0 is the migration to C99 standard integer types. The LargestIntegralType typedef has been replaced with intmax_t and uintmax_t from stdint.h, providing better type safety and portability across different platforms. Additionally, we've adopted the bool type where appropriate, making the code more expressive and self-documenting.

Using intmax_t and uintmax_t also allows to print better error messages. So you can now find e.g. assert_int_equal and assert_uint_equal.

cmocka 2.0 introduces a comprehensive set of type-specific assertion macros, including `assert_uint_equal()`, `assert_float_equal()`, and enhanced pointer assertions. The mocking system has also been significantly improved with type-specific macros like `will_return_int()` and `will_return_float()`. The same for parameter checking etc.

LWN covered the project early in its development in 2013. See the full list of new features, enhancements, and bug fixes in cmocka 2.0 in the changelog.

Loris Cro has published a detailed YouTube video talking about the terminology used to discuss asynchronicity, concurrency, and parallelism in our recent article about Zig's new Io interface. Our article is not completely clear because it uses the term "asynchronous I/O" to refer to what should really be called "non-blocking I/O", and sometimes confuses asynchronicity for concurrency, among other errors of terminology, he says. Readers interested in precise details about Zig's approach and some of the motivation behind the design may find Cro's video interesting.

• Front: Rust in Debian; Python comprehensions; asynchronous Zig; BPF and io_uring; C safety; 6.18 statistics; just.
• Briefs: Landlock; Let's Encrypt lifetimes; Last 5.4 kernel; TAB election; AlmaLinux 10.1; FreeBSD 15.0; NixOS 25.11; Django 6.0; Home Assistant 2025.12; PHP 8.5.0; Racket 9.0; Quotes; ...
• Announcements: Newsletters, conferences, security updates, patches, and more.

This month, we're unveiling Home Assistant Labs, a brand-new space where you can preview features before they go mainstream. And what better way to kick it off than with Winter mode? ❄️ Enable it and watch snowflakes drift across your dashboard. It's completely unnecessary, utterly delightful, and exactly the kind of thing we love to build. ❄️

But that's just the beginning. We've been working on making automations more intuitive over the past releases, and this release finally delivers purpose-specific triggers and conditions. Instead of thinking in (numeric) states, you can now simply say "When a light turns on" or "If the climate is heating". It's automation building the way our mind works, as it should be.

Over time, many Linux users wind up with a collection of aliases, shell scripts, and makefiles to run simple commands (or a series of commands) that are often used, but challenging to remember and annoying to type out at length. The just command runner is a Rust-based utility that just does one thing and does it well: it reads recipes from a text file (aptly called a "justfile"), and runs the commands from an invoked recipe. Rather than accumulating a library of one-off shell scripts over time, just provides a cross-platform tool with a framework and well-documented syntax for collecting and documenting tasks that makes it useful for solo users and collaborative projects.

Greg Kroah-Hartman has announced the release of the 5.4.302 stable kernel:

This is the LAST 5.4.y release. It is now end-of-life and should not be used by anyone, anymore. As of this point in time, there are 1539 documented unfixed CVEs for this kernel branch, and that number will only increase over time as more CVEs get assigned for kernel bugs.

For the curious, Kroah-Hartman has also provided a list of the unfixed CVEs for 5.4.302.

Let's Encrypt has announced that it will be reducing the validity period of its certificates from 90 days to 45 days by 2028:

Most users of Let's Encrypt who automatically issue certificates will not have to make any changes. However, you should verify that your automation is compatible with certificates that have shorter validity periods.

To ensure your ACME client renews on time, we recommend using ACME Renewal Information (ARI). ARI is a feature we've introduced to help clients know when they need to renew their certificates. Consult your ACME client's documentation on how to enable ARI, as it differs from client to client. If you are a client developer, check out this integration guide.

If your client doesn't support ARI yet, ensure it runs on a schedule that is compatible with 45-day certificates. For example, renewing at a hardcoded interval of 60 days will no longer be sufficient. Acceptable behavior includes renewing certificates at approximately two thirds of the way through the current certificate's lifetime.

Manually renewing certificates is not recommended, as it will need to be done more frequently with shorter certificate lifetimes.