Linux Weekly News

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.

Greg Kroah-Hartman has announced the release of the 6.11.4, 6.6.57, 6.1.113, 5.15.168, and 5.10.227 stable kernels. As usual, this set of updates contains a long list of important fixes throughout the kernel tree.

Security updates have been issued by Debian (python-cryptography), Fedora (dnsdist and python-virtualenv), Red Hat (java-1.8.0-openjdk, java-11-openjdk, java-17-openjdk, and java-21-openjdk), Slackware (libssh2 and mozilla), SUSE (haproxy, keepalived, libarchive, libnss_slurm2, php8, and python310-pytest-html), and Ubuntu (linux, linux-aws, linux-aws-5.15, linux-gcp, linux-gcp-5.15, linux-gkeop, linux-gkeop-5.15, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-intel-iotg, linux-intel-iotg-5.15, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-nvidia, linux-oracle, linux-oracle-5.15, linux-raspi, linux-xilinx-zynqmp, linux, linux-aws, linux-aws-5.4, linux-bluefield, linux-gcp, linux-gcp-5.4, linux-gkeop, linux-hwe-5.4, linux-ibm, linux-ibm-5.4, linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4, linux-xilinx-zynqmp, and linux, linux-aws, linux-aws-6.8, linux-gcp, linux-gcp-6.8, linux-hwe-6.8, linux-ibm, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency, linux-oem-6.8, linux-oracle, linux-oracle-6.8, linux-raspi).

The LWN.net Weekly Edition for October 17, 2024 is available.

Version 9.0 of the Forgejo software forge system has been released. Changes include a switch to the GPLv3 license, the beginning of a quota system, the removal of go-git support, and a lot of fixes. (LWN looked at Forgejo in February).

Rust, like C, has its own memory model describing how concurrent access to the same data by multiple threads can behave. The Linux kernel, however, has its own ideas. The Linux kernel memory model (LKMM) is subtly different from both the standard C memory model and Rust's model. At Kangrejos, Boqun Feng gave a presentation about the need to reconcile the memory models used by Rust and the kernel, including a few potential avenues for doing so. While no consensus was reached, it is an area of active discussion.

The pidfd mechanism, which uses file descriptors to refer to processes in an unambiguous and race-free way, was first introduced in 2018. Since then, the interface has gained a number of new features, but development has slowed over time as the interface has matured. There are, however, a couple of patches in circulation that are meant to make working with pidfds simpler in some situations.

Security updates have been issued by AlmaLinux (buildah, containernetworking-plugins, and skopeo), Fedora (pdns-recursor and valkey), Mageia (unbound), Red Hat (fence-agents, firefox, java-11-openjdk, python-setuptools, python3-setuptools, resource-agents, and thunderbird), SUSE (etcd-for-k8s, libsonivox3, rubygem-puma, and unbound), and Ubuntu (apr, libarchive, linux, linux-aws, linux-aws-hwe, linux-azure-4.15, linux-gcp, linux-gcp-4.15, linux-hwe, linux-kvm, linux-oracle, nano, and vim).

Version 4.0.0 of the LibreSSL TLS/cryptography stack has been released. Changes include a cleanup of the MD4 and MD5 implementations, removal of unused DSA methods, changes in libtls protocol parsing to ignore unsupported TLSv1.1 and TLSv1.0 protocols, and many more internal changes and bug fixes.

Security updates have been issued by AlmaLinux (container-tools:rhel8, firefox, OpenIPMI, podman, and thunderbird), Debian (libapache-mod-jk, php7.4, and webkit2gtk), Fedora (edk2, koji, libgsf, 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, and rust-tower0.4), Mageia (packages and thunderbird), Oracle (bind, container-tools:ol8, kernel, kernel-container, OpenIPMI, podman, and thunderbird), Red Hat (container-tools:rhel8, containernetworking-plugins, podman, and skopeo), SUSE (argocd-cli, bsdtar, keepalived, kernel, kyverno, libmozjs-115-0, libmozjs-128-0, libmozjs-78-0, OpenIPMI, opensc, php8, thunderbird, and xen), and Ubuntu (configobj, haproxy, imagemagick, nginx, and postgresql-10, postgresql-9.3).

Paul McKenney gave a presentation at Kangrejos this year that wasn't (directly) related to Rust. Instead, he spoke about the work he has been doing in concert with many other contributors on improving the handling of subtle concurrency problems in C++. Although he cautioned that his talk was only an overview, and not a substitute for reading the relevant papers, he hoped that the things the C++ community is working on would be of interest to the Rust developers present as well, and potentially inform future work on the language. McKenney's talk was, as is his style, full of subtle examples of weird multithreaded behavior. Interested readers may wish to refer to his slides in an attempt to follow along.

Version 1.4 of the Inkscape open-source vector-graphics editor has been released. Highlights of this release include a filter gallery, import for Affinity Designer files, internal links in exported PDFs, and more. See the release notes for all of the new features. LWN previewed the 1.4 release in early October.