LWN.net

The Image-Based Linux Summit has by now established itself as a yearly event. Following on from last year's edition, the third edition was held in Berlin on September 24, the day before All Systems Go! 2024 (ASG). The purpose of this event is to gather stakeholders from various engineering groups and hold friendly but lively discussions around the topic of image-based Linux — that is, Linux distributions based around immutable images, instead of mutable root filesystems.

The AlmaLinux project has introduced a new edition called "Kitten", which will serve as "the direct upstream for AlmaLinux OS and is the primary point for the AlmaLinux community to engage and influence the future of AlmaLinux OS". Not intended for production use, the first release is based on CentOS Stream 10 source, which will eventually be the basis for Red Hat Enterprise Linux (RHEL) 10:

Because we anticipated many changes in 10, we wanted to get a head start on building AlmaLinux OS 10. Earlier this year we started setting up infrastructure and the build pipeline for AlmaLinux OS 10, and started testing using CentOS Stream 10's code. Based on this preparation work, we are excited to share that we have successfully built a preview of AlmaLinux OS 10 that we are calling AlmaLinux OS Kitten 10.

The first Kitten release previews a number of ways that AlmaLinux will diverge from RHEL 10, including re-enabling frame pointers, including Simple Protocol for Independent Computing Environments (SPICE), and adding packages for Firefox and Thunderbird, which have been dropped from CentOS Stream 10 in favor of Flatpak versions. New installation images for Kitten will be built quarterly. See the release notes for download links, installation instructions, and more information.

The 6.11.5, 6.6.58, 6.1.114, 5.15.169, and 5.10.228 stable kernels have all been released; each contains another set of important fixes.

Version 3.4.0 of the OpenSSL SSL/TLS library has been released. It adds a number of new encryption algorithms, support for "directly fetched composite signature algorithms such as RSA-SHA2-256", and more. See the release notes for details.

Security updates have been issued by Debian (ffmpeg, ghostscript, libsepol, openjdk-11, openjdk-17, perl, and python-sql), Oracle (389-ds-base, buildah, containernetworking-plugins, edk2, httpd, java-1.8.0-openjdk, java-11-openjdk, java-17-openjdk, java-21-openjdk, kernel, python-setuptools, skopeo, and webkit2gtk3), Red Hat (buildah), Slackware (openssl), SUSE (apache2, firefox, libopenssl-3-devel, podman, and python310-starlette), and Ubuntu (cups-browsed, firefox, libgsf, and linux-gke).

Sasha Levin has announced a new tree that is intended to perform continuous-integration tests of pull requests aimed at the mainline. The plan is for this tree to hold more finished work than sometimes ends up in linux-next; in a name that seems destined to create typographical confusion, it is called "linus-next".

The linus-next tree aims to provide a more stable and testable integration point compared to linux-next, addressing the runtime issues that make testing linux-next challenging and focusing on code that's about to be pulled by Linus.

Version 1.1.0 of the bootc utility for performing transactional, in-place operating system updates using Open Container Initative (OCI) images, has been released. This release "officially stabilizes all APIs" for bootc and includes a number of bug fixes. LWN covered bootc in June.

Sigstore is a project that is meant to simplify and improve the process of signing, verifying, and protecting software. It is a relatively new project, declared "generally available" in 2022. Python is an early adopter of sigstore; it started providing signatures for CPython artifacts with Python 3.11 in 2022. This is in addition to the OpenPGP signatures it has been providing since at least 2001. Now, Seth Michael Larson—the Python Software Foundation (PSF) security developer-in-residence—would like to deprecate the PGP signature and move to sigstore exclusively by next year. If that happens, it will involve some changes in the way that Linux distributions verify Python releases, since none of the major distributions have processes for working with sigstore.

Security updates have been issued by Debian (asterisk, chromium, php-horde-mime-viewer, and php-horde-turba), Fedora (apache-commons-io, buildah, chromium, containers-common, libarchive, libdigidocpp, oath-toolkit, podman, rust-hyper-rustls, rust-reqwest, rust-rustls-native-certs, rust-rustls-native-certs0.7, rust-tonic, rust-tonic-build, rust-tonic-types, rust-tower, rust-tower-http, rust-tower-http0.5, rust-tower0.4, thunderbird, and unbound), SUSE (buildah, chromedriver, chromium, element-desktop, element-web, jetty-annotations, nodejs-electron, php7, php74, php8, podman, python3-virtualbox, qemu, thunderbird, and valkey), and Ubuntu (amd64-microcode).

The Guix project has disclosed a security vulnerability in the build daemon that the distribution uses to build and install software locally. The vulnerability allows an existing unprivileged user to get access to a setuid binary, and from there potentially interfere with any other software built or installed on the computer. The project recommends upgrading the guix daemon now, to avoid the issue.

This exploit requires the ability to start a derivation build and the ability to run arbitrary code with access to the store in the root PID namespace on the machine the build occurs on. As such, this represents an increased risk primarily to multi-user systems and systems using dedicated privilege-separation users for various daemons: without special sandboxing measures, any process of theirs can take advantage of this vulnerability.

Linus has released 6.12-rc4 for testing. "I'm not happy with how big this is - it's probably far from the biggest rc4 ever, but it _is_ the biggest rc4 we've had in the 6.x series at least in number of commits."

The kernel's CPU scheduler currently offers several preemption modes that implement a range of tradeoffs between system throughput and response time. Back in September 2023, a discussion on scheduling led to the concept of "lazy preemption", which could simplify scheduling in the kernel while providing better results. Things went quiet for a while, but lazy preemption has returned in the form of this patch series from Peter Zijlstra. While the concept appears to work well, there is still a fair amount of work to be done.

Security updates have been issued by AlmaLinux (java-1.8.0-openjdk, java-11-openjdk, java-17-openjdk, java-21-openjdk, and webkit2gtk3), Debian (apache2), Red Hat (expat), SUSE (cups-filters, jetty-minimal, OpenIPMI, and python-starlette), and Ubuntu (linux-azure, linux-azure, linux-azure-5.15, linux-azure, linux-azure-5.4, and oath-toolkit).

Version 1.82.0 of the Rust language has been released. There are a lot of new features this time, including a cargo info command, tier-1 support for 64-bit Apple Arm systems, a new native syntax (&raw) to create raw pointers, changes to unsafe extern, unsafe attributes, standardized rules around the handling of floating-point not-a-number values, and more.

Email has become somewhat unfashionable as a collaboration tool for open-source projects, but there are still a number of projects—such as PostgreSQL and the Linux kernel—that expect contributors to send and review patches via email. The aerc mail client is aimed at developers looking for a text-based, efficient, and extensible client that is meant to be used for working with Git and email. It uses Vim-style keybindings by default, and has an interface inspired by tmux that lets users manage multiple accounts, mails, and embedded terminals at once.