Vue lecture

Stable kernel 6.6.82

✇LWN
Par : corbet
The 6.6.82 stable kernel has been released. "All i386 users of the 6.6 kernel series must upgrade (as they skipped the last release.) All other arches can skip this one as it should not affect them."

Four more stable kernel updates

✇LWN
Par : daroc

Greg Kroah-Hartman has announced the release of four more stable kernels: 6.13.6, 6.12.18, 6.6.81, and 6.1.130. Unlike a normal release, Kroah-Hartman did not call for all users to update their kernels. Specifically, the 6.6.81 kernel is currently broken on i386 systems, and users should wait for 6.6.82.

[$] Hash-based module integrity checking

✇LWN
Par : daroc

On January 20, Thomas Weißschuh shared a new patch set implementing an alternate method for checking the integrity of loadable kernel modules. This mechanism, which checks module integrity based on hashes computed at build time instead of using cryptographic signatures, could enable reproducible kernel builds in more contexts. Several distributions have already expressed interest in the patch set if Weißschuh can get it into the kernel.

Security updates for Friday

✇LWN
Par : daroc
Security updates have been issued by Debian (chromium), Fedora (firefox and man2html), Mageia (erlang, ffmpeg, and vim), Oracle (doxygen, firefox, python-jinja2, squid, and webkit2gtk3), Red Hat (nodejs:18), SUSE (emacs, go1.23, go1.24, and pcp), and Ubuntu (ansible, firefox, linux-azure, linux-nvidia, and python-django).

[$] Timer IDs, CRIU, and ABI challenges

✇LWN
Par : corbet
The kernel project has usually been willing to make fundamental internal changes if they lead to a better kernel in the end. The project also, though, goes out of its way to avoid breaking interfaces that have been exposed to user space, even if programs come to rely on behavior that was never documented. Sometimes, those two principles come into conflict, leading to a situation where fixing problems within the kernel is either difficult or impossible. This sort of situation has been impeding performance improvements in the kernel's POSIX timers implementation for some time, but it appears that a solution has been found.

Security updates for Thursday

✇LWN
Par : jake
Security updates have been issued by Debian (firefox-esr), Fedora (firefox and vim), Red Hat (firefox), Slackware (mozilla), SUSE (firefox, firefox-esr, kernel, and podman), and Ubuntu (gpac, kernel, linux, linux-aws, linux-gcp, linux-gcp-5.15, linux-gke, linux-hwe-5.15, and redis).

[$] LWN.net Weekly Edition for March 6, 2025

✇LWN
Par : corbet
Inside this week's LWN.net Weekly Edition:

  • Front: Firefox forks; Bend and Vine; FineIBT; Guard pages; Fedora's Flatpak packaging; Zotero.
  • Briefs: LFS 12.3; FerretDB 2.0; Firefox; Fish 4.0; Incus 6.10; Thunderbird 136.0; Xen 4.20; Quotes; ...
  • Announcements: Newsletters, conferences, security updates, patches, and more.

Zen and the Art of Microcode Hacking (Google Bug Hunters)

✇LWN
Par : corbet
The Google Bug Hunters blog has a detailed description of how a vulnerability in AMD's microcode-patching functionality was discovered and exploited; the authors have also released a set of tools to assist with this kind of research in the future.

Secure hash functions are designed in such a way that there is no secret key, and there is no way to use knowledge of the intermediate state in order to generate a collision. However, CMAC was not designed as a hash function, and therefore it is a weak hash function against an adversary who has the key. Remember that every AMD Zen CPU has to have the same AES-CMAC key in order to successfully calculate the hash of the AMD public key and the microcode patch contents. Therefore, the key only needs to be revealed from a single CPU in order to compromise all other CPUs using the same key. This opens up the potential for hardware attacks (e.g., reading the key from ROM with a scanning electron microscope), side-channel attacks (e.g., using Correlation Power Analysis to leak the key during validation), or other software or hardware attacks that can somehow reveal the key. In summary, it is a safe assumption that such a key will not remain secret forever.

[$] Two new graph-based functional programming languages

✇LWN
Par : daroc

Functional programming languages have a long association with graphs. In the 1990s, it was even thought that parallel graph-reduction architectures could make functional programming languages much faster than their imperative counterparts. Alas, that prediction mostly failed to materialize. Even though graphs are still used as a theoretical formalism in order to define and optimize functional languages (such as Haskell's spineless tagless graph-machine), they are still mostly compiled down to the same old non-parallel assembly code that every other language uses. Now, two projects — Bend and Vine — have sprung up attempting to change that, and prove that parallel graph reduction can be a useful technique for real programs.

Thunderbird Desktop 136.0 released

✇LWN
Par : jzb

Version 136.0 of the Thunderbird Desktop mail client has been released. The release includes a quick toggle for adapting messages to dark mode, and a new "Appearance" setting to control message threading and sorting order globally, as well as a number of bug fixes. See the security advisory for a full list of security vulnerabilities addressed in Thunderbird 136.0.

Linux from Scratch version 12.3 released

✇LWN
Par : jzb

Version 12.3 of Linux From Scratch (LFS) has been released, along with Beyond Linux From Scratch (BLFS) 12.3. LFS provides step-by-step instructions on building a customized Linux system entirely from source, and BLFS helps to extend an LFS installation into a more usable system. Notable changes in this release include toolchain updates to GNU Binutils 2.44, GNU C Library (glibc) 2.41, and Linux 6.13.2. The Changelog has a full list of changes since the previous stable release.

Security updates for Wednesday

✇LWN
Par : jzb
Security updates have been issued by Debian (libreoffice), Fedora (exim and fscrypt), Red Hat (kernel), Slackware (mozilla), SUSE (docker, firefox, and podman), and Ubuntu (linux, linux-lowlatency, linux-lowlatency-hwe-5.15, linux, linux-lowlatency, linux-lowlatency-hwe-6.8, linux, linux-oem-6.11, linux-aws, linux-aws-6.8, linux-oracle, linux-oracle-6.8, linux-raspi, linux-aws, linux-gcp, linux-hwe-6.11, linux-oracle, linux-raspi, linux-realtime, linux-aws, linux-gkeop, linux-ibm, linux-intel-iotg, linux-intel-iotg-5.15, linux-oracle, linux-oracle-5.15, linux-raspi, and linux-gcp, linux-gcp-6.8, linux-gke, linux-gkeop).

[$] A look at Firefox forks

✇LWN
Par : jzb

Mozilla's actions have been rubbing many Firefox fans the wrong way as of late, and inspiring them to look for alternatives. There are many choices for users who are looking for a browser that isn't part of the Chrome monoculture but is full-featured and suitable for day-to-day use. For those who are willing to stay in the Firefox "family" there are a number of good options that have taken vastly different approaches. This includes GNU IceCat, Floorp, LibreWolf, and Zen.

Firefox 136.0 released

✇LWN
Par : corbet
Version 136.0 of the Firefox browser has been released. Changes include a new vertical tab layout, an automatic attempt to upgrade HTTP connections to HTTPS, support for AMD GPUs on Linux, an Arm64 port for Linux, and more.

Incus 6.10 released

✇LWN
Par : corbet
Version 6.10 of the Incus container-management system has been released. New features include better Let's Encrypt support, API-wide filtering, IOMMU support in virtual machines, and more. See this announcement for details.

Security updates for Tuesday

✇LWN
Par : corbet
Security updates have been issued by AlmaLinux (kernel), Mageia (x11-server), Red Hat (emacs and webkit2gtk3), SUSE (ffmpeg-7, govulncheck-vulndb, kernel, and skopeo), and Ubuntu (cmark-gfm, erlang, krb5, linux-gcp-6.8, linux-raspi, linux-kvm, lucene-solr, postgresql-12, postgresql-14, postgresql-16, raptor2, spip, tomcat7, and wpa).

Mozilla reverses course on its terms of use

✇LWN
Par : jzb

Mozilla has issued an update to its terms of use (TOU) that were announced on February 26. It has removed a reference in the TOU to Mozilla's Acceptable Use Policy "because it seems to be causing more confusion than clarity", and has revised the TOU "to more clearly reflect the limited scope of how Mozilla interacts with user data". The new language says:

You give Mozilla the rights necessary to operate Firefox. This includes processing your data as we describe in the Firefox Privacy Notice. It also includes a nonexclusive, royalty-free, worldwide license for the purpose of doing as you request with the content you input in Firefox. This does not give Mozilla any ownership in that content.

Mozilla has also updated its Privacy FAQ to provide more detail about its reasons for the changes.

[$] Guard pages for file-backed memory

✇LWN
Par : corbet
One of the many new features packed into the 6.13 kernel release was guard pages, a hardening mechanism that makes it possible to inject zero-access pages into a process's address space in an efficient way. That feature only supports anonymous (user-space data) pages, though. To make guard pages more widely useful, Lorenzo Stoakes has put together a patch set enabling the feature for file-backed pages as well; in the process, he examined and resolved a long list of potential problems that extending the feature could encounter. One potential problem was not on his list, though.
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