LWN.net

The Linux security module (LSM) mechanism was created as a result of the first Kernel Summit in 2001; it wasdesigned to allow the development of multiple approaches to Linux security.That goal has been met; there are several security modules available withcurrent kernels. The LSM subsystem was not designed, though, to allowmultiple security modules to work together on the same system. Developershave been working to rectify that problem almost since the LSM subsystemwas merged, but with limited success; some small security modules can bestacked on top of the "major" ones, but arbitrary stacking is not possible.Now, a full 20 years aftersecurity-module support went into the 2.5 development kernel series, itlooks like a solution to the stacking problem may finally be gettingcloser.

Security updates have been issued by Debian (batik, chromium, expat, libxml2, ncurses, openvswitch, pysha3, python-django, thunderbird, and tomcat9), Fedora (cacti, cacti-spine, curl, mbedtls, mingw-expat, and xen), Gentoo (apptainer, bind, chromium, exif, freerdp, gdal, gitea, hiredis, jackson-databind, jhead, libgcrypt, libksba, libtirpc, lighttpd, net-snmp, nicotine+, open-vm-tools, openexr, rpm, schroot, shadow, sofia-sip, tiff, and xorg-server), Mageia (libreoffice), Oracle (expat), Red Hat (device-mapper-multipath), and SUSE (cacti, cacti-spine, chromium, exim, jhead, kernel, libmad, opera, and pdns-recursor).

Version 4.4 of the GNU make utility is out. There is a long list ofchanges and a fair number of potential compatibility issues; see theannouncement text for all the details.

The 6.1-rc3 kernel prepatch is out fortesting.

The 5.10.151 kernel was released onOctober 28 with a small fix to the PAHOLE_FLAGS in the kernelbuild. October 29 saw the release of the 6.0.6, 5.15.76, and 5.4.221 stable kernels, each with the usualcollection of important fixes throughout the tree.Update: 5.10.152 has now also beenreleased with another set of important fixes.

The Rust Types Team announcesthat the long-awaited generic associated types feature will be stable in Rust 1.65.

Linux distributions were, as a general rule, designed during an era whenmost software of interest was written in C; as a result, distributionsare naturally able to efficiently package C applications and the librariesthey depend on. Modern languages, though, tend to be built around theirown package-management systems that are designed with different goals inmind. The result is that, for years, distributors have struggled to findthe best ways to package and ship applications written in those languages.A recent discussion in the Fedora community on the packaging of Rustapplications shows that the problems have not yet all been solved.

Security updates have been issued by Debian (expat, ruby-sinatra, and thunderbird), Fedora (glances), Mageia (cups, firefox, git, heimdal, http-parser, krb5-appl, minidlna, nginx, and thunderbird), Oracle (389-ds:1.4, device-mapper-multipath, firefox, mysql:8.0, postgresql:12, and thunderbird), SUSE (dbus-1, libconfuse0, libtasn1, openjpeg2, qemu, and thunderbird), and Ubuntu (dbus, linux-azure-fde, and tiff).

Fedora releases have traditionally happened later than their target date,though the project has done better on that score in recent years. BenCotton has announced inFedora Magazine that the upcoming Fedora 37 release, initially plannedfor October 25, won't be happening until November 15. Theimmediate cause is animpending OpenSSL update which fixes a vulnerability described as"critical".

The practice of requiring copyright assignments for contributions tofree-software projects has been in decline for years; the GNU Binutilsproject may be thelatest domino to fall in that regard. The Linux kernel project,unlike some others, has always allowed contributors to retain their copyrights,resulting in a code base that has widely distributed ownership. In such aproject, who owns the copyright to a given piece of code is not alwaysobvious. Somedevelopers (or their employers) are insistent about the placement ofcopyright notices in the code to document their ownership of parts of thekernel. A series of recent discussions within the Btrfs subsystem, though,has made it clear that there is no project-wide policy on when thesenotices are warranted — or even acceptable.

ThisLaravel News article digs into the many enhancements that have foundtheir way into the PHP language in the last couple of years or so.

Mara Bos has written a lengthyblog post on whether the Rust language needs to be standardized.The answer is "no" — but she draws a distinction between a "standard"(maintained by some distant standards body) and a "specification".

Security updates have been issued by CentOS (389-ds-base, bind, expat, java-1.8.0-openjdk, java-11-openjdk, libksba, and squid), Debian (chromium, libdatetime-timezone-perl, tzdata, and wordpress), Fedora (dbus, dhcp, dotnet3.1, jhead, samba, and strongswan), Mageia (virtualbox), Oracle (device-mapper-multipath), Scientific Linux (device-mapper-multipath and thunderbird), Slackware (curl), SUSE (container-suseconnect, curl, kernel, libmad, libtasn1, libtirpc, qemu, rubygem-puppet, SUSE Manager Client Tools, and telnet), and Ubuntu (curl, linux-intel-iotg, and mysql-5.7).

The LWN.net Weekly Edition for October 27, 2022 is available.

Python has lots of different options for mutable data structures, bothdirectly in the language and in the standard library. Lists, dictionaries (or "dicts"), andsets are the foundation, but two of those maintain an order based on howthe elements are added, while sets do not. A recent discussion on the Python Discourse forum raised theidea of adding an ordered variant of sets; while it does not look likethere is a big push to add the feature, the discussion did show some ofwhat is generally needed to get new things into the language—and could welllead to its inclusion.

Arturo Borrero González has posted a detailedsummary of the Netfilter workshop that was recently held in Seville."This year, the number of participants was just eight people, and thisallowed the setup to be a bit more informal. We had kind of anun-conference style meeting, in which whoever had something prepared justwent ahead and opened a topic for debate."(Thanks to Paul Wise).

The6.0.4,5.15.75,5.10.150,5.4.220,4.19.262,4.14.296, and4.9.331stable kernel updates have all been released; each contains a relativelylarge set of important fixes. The 6.0.5update followed about 90 seconds later with a couple of additionalsmall fixes.

Security updates have been issued by Debian (tomcat9), Oracle (389-ds-base, device-mapper-multipath, firefox, git-lfs, gnutls, kernel, kernel-container, libksba, pki-core, samba, sqlite, and zlib), Red Hat (device-mapper-multipath, kernel, kpatch-patch, libksba, and thunderbird), Slackware (expat and samba), SUSE (bind, buildah, curl, firefox, golang-github-prometheus-node_exporter, grafana, icinga2, python-paramiko, python-waitress, SUSE Manager Client Tools, telnet, and xen), and Ubuntu (glibc, jinja2, libksba, linux, linux-aws, linux-azure, linux-gcp, linux-ibm, linux-kvm, linux-lowlatency, linux-oracle, linux-raspi, and openvswitch).

Lennart Poettering has posted adetailed specification for a new approach to "trusted computing"systems.

The QEMU emulator has a sizable set ofstorage features, including disk-image file formats like qcow2, snapshots, incremental backup, and storage migration, which are available to virtualmachines. This software-defined storage functionality that is availableinside QEMU has not been easily accessible outside of it, however. Kevin Wolf and Stefano Garzarellapresented at KVM Forum 2022 on the new qemu-storage-daemon program and the libblkiolibrary that make QEMU's storage functionality available even when the goalis not to run a virtual machine (VM).

Security updates have been issued by Debian (libbluray and wkhtmltopdf), Fedora (firefox, libksba, libmodsecurity, libxml2, qemu, and xmlsec1), Red Hat (389-ds-base, 389-ds:1.4, git-lfs, gnutls, java-1.8.0-ibm, kernel, kernel-rt, kpatch-patch, libksba, mysql:8.0, pki-core, postgresql:12, samba, sqlite, and zlib), Scientific Linux (389-ds-base, libksba, and pki-core), SUSE (bluez, firefox, jdom, kernel, libosip2, libxml2, multipath-tools, and python-Mako), and Ubuntu (barbican, mysql-5.7, mysql-8.0, openvswitch, and pillow).

Version3.11.0 of the Python language has been released."In the CPython release team, we have put a lot of effort into making3.11 the best version of Python possible. Better tracebacks, faster Python,exception groups and except*, typing improvements and much more."Among other things, this release claims a 1.22x speedup on the standardbenchmark suite thanks to the FasterCPython work.

Among the many quirks that make the C language so charming is the set ofbehaviors thatit does not define; these include whether a char variable is asigned quantity or not. The distinction often does not make a difference,but there are exceptions. Kernel code, which runs on many differentarchitectures, is where exceptions can certainly be found. A recentattempt to eliminate the uncertain signedness of char variablesdid not get far — at least not in the direction it originally attempted togo.

Greg Kroah-Hartman has announced the release of the 5.19.17 stable kernel. "Note this is theLAST 5.19.y kernel to be released. This branch is now end-of-life. You should move to the 6.0.y branch at this point in time."

Alex Gaynor examines theawkwardness that comes when trying to interface Python and Rust code.

Security updates have been issued by Debian (bluez, kernel, and lava), Fedora (ckeditor, drupal7, moby-engine, php-Smarty, and wavpack), Mageia (bind, e2fsprogs, epiphany, freerdp, kernel, kernel-linus, libconfuse, libosip2, ntfs-3g, perl-Image-ExifTool, and poppler), Oracle (firefox, java-1.8.0-openjdk, java-11-openjdk, java-17-openjdk, kernel, kernel-container, and thunderbird), Scientific Linux (firefox, java-1.8.0-openjdk, and java-11-openjdk), SUSE (bluez, firefox, kernel, libxml2, and tiff), and Ubuntu (linux-gcp).

The second 6.1 kernel prepatch is out fortesting. "Usually rc2 is a pretty quiet week, and it mostly started outthat way too, but then things took a turn for the strange. End result:6.1-rc2 ended up being unusually large."

The U-Boot list carriesthe sad news that Wolfgang Denk, the founder of the U-Boot project, haspassed away.

All memory accesses in a BPF program arestatically checked for safety using the verifier, which analyzes the program in itsentirety before allowing it to run. While this allows BPF programs tosafely run in kernel space, it restricts how that program is able to usepointers. Until recently, one such constraint was that the size of a memoryregion referenced by a pointer in a BPF program must be statically knownwhen a BPF program is loaded. A recentpatch set by Joanne Koong enhances BPF to support loading programs withpointers to dynamically sized memory regions.

The 6.0.3 stable kernel update has beenreleased; it contains over 800 important fixes.

Security updates have been issued by Fedora (poppler), Oracle (firefox and thunderbird), Red Hat (firefox, java-1.8.0-openjdk, java-11-openjdk, and java-17-openjdk), SUSE (bind, clone-master-clean-up, grafana, libksba, python3, tiff, and v4l2loopback), and Ubuntu (libreoffice).

Part of the early appeal of the World Wide Web was the promise that anybodycould create a site and publish interesting content to the world. A fewdecades later, that promise seems to have been transformed into the ability toprovide content for a small number of proprietary platforms run by hugecorporations.But, arguably, the dream of widespread independent publishing is enjoying aresurgence. The Ghost publishing platformis built around the goal of making publishing technology — and the abilityto make money from it — available with free software.

Ubuntu22.10 has been released. "Codenamed 'Kinetic Kudu', this interimrelease improves the experience of enterprise developers and ITadministrators. It also includes the latest toolchains and applicationswith a particular focus on the IoT ecosystem." See therelease notes for details.

Security updates have been issued by Debian (firefox-esr), Red Hat (java-1.8.0-openjdk, java-11-openjdk, java-17-openjdk, OpenShift Container Platform 4.9.50 bug fix and, and rh-nodejs14-nodejs), SUSE (buildah, clone-master-clean-up, go1.18, go1.19, helm, jasper, libostree, nodejs16, php8, qemu, and xen), and Ubuntu (libxdmcp, linux, linux-aws, linux-aws-5.15, linux-azure, linux-azure-5.15, linux-gcp, linux-gcp-5.15, linux-gke, linux-gke-5.15, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-oem-5.14, linux-oracle, linux-raspi, linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-gcp-5.4, linux-gke, 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-oem-5.17, and perl).

The LWN.net Weekly Edition for October 20, 2022 is available.

Unlike many other architectures, x86 systems support atomic operations thataffect more than one cache line. This support comes at a cost, though, interms of overall system performance and, even, security. Over the last fewyears, kernel developers have worked to discourage the use of this sort of"split-lock" operation. Now, though, one group of users is feelinga little too discouraged, leading to a discussion of how much misery canappropriately be inflicted upon users who use problematic butarchitecturally legal operations.

Security updates have been issued by Debian (bcel, kernel, node-xmldom, and squid), Mageia (chromium-browser-stable, dhcp, dokuwiki, firefox, golang, python-joblib, sos, and unzip), Oracle (nodejs and nodejs:16), Red Hat (firefox, kernel, kernel-rt, nodejs, nodejs:14, and thunderbird), Scientific Linux (firefox and thunderbird), Slackware (git and mozilla), SUSE (amazon-ssm-agent, caasp-release, cri-o, patchinfo, release-notes-caasp, skuba, enlightenment, libreoffice, netty, nodejs12, nodejs14, nodejs16, pngcheck, postgresql-jdbc, python-waitress, rubygem-activesupport-5_1, and tcl), and Ubuntu (frr, git, libksba, and linux-azure-4.15).

Since its inclusion in the Linux kernel, the WireGuard VPN tunnel has becomeincreasingly popular. In general, WireGuard is simpler to configure thanother VPNs, but the approach that it takes to authentication can presentsome challenges. Each node in a WireGuard network has a cryptographic keythat serves as the node's identity; nodes that do not know each other's keys cannot directly communicate.Keepingtrack of these keys and distributing them to the other nodesin a mesh network quickly becomes a chore as the network grows.Fortunately, there are now several open-source tools that can automate the management of these keys and make usingWireGuard easier for both administrators and end users.

Version106.0 of the Firefox browser has been released. There are several newfeatures, including PDF editing, FirefoxView (an overview of recently closed tabs), and a set of new colorschemes.

Security updates have been issued by Debian (glibc and libksba), Fedora (dhcp and kernel), Red Hat (.NET 6.0, .NET Core 3.1, compat-expat1, kpatch-patch, and nodejs:16), Slackware (xorg), SUSE (exiv2, expat, kernel, libreoffice, python, python-numpy, squid, and virtualbox), and Ubuntu (linux-azure and zlib).

Version5.5 of the Tor-centered Tails distribution is out. The biggest changeappears to be a significant update to the Thunderbird email client.

The5.10.149 and5.4.219stable kernel updates have been released. These small updates contain only afew more WiFi fixes and one revert.

Linus Torvalds released6.1-rc1 and closed the 6.1 merge window on October 16; at that point, 11,537 non-merge changesets had been pulledinto the mainline repository. That is considerably less than the 13,543changesets pulled during the 6.0 merge window, but quantity is noteverything: there were quite a few significant changes brought in this timearound. Many of those were part of the nearly 5,800 changesets pulledsince our first 6.1 merge window summary;read on for a look at some of the work done in the latter part of thismerge window.

Version 2.3.8 of the GNU Privacy Guard is out. It contains a few newfeatures but the real purpose is to fix CVE-2022-3515,an integer overflow vulnerability that can be exploited remotely for codeexecution via a, for example, malicious S/MIME attachment. Note that theactual vulnerability is in the libksba library, which isnormally packaged separately on Linux systems.

Security updates have been issued by Arch Linux (kernel, linux-hardened, linux-lts, and linux-zen), Debian (python-django), Fedora (apptainer, kernel, python3.6, and vim), Gentoo (assimp, deluge, libvirt, libxml2, openssl, rust, tcpreplay, virglrenderer, and wireshark), Slackware (zlib), SUSE (chromium, python3, qemu, roundcubemail, and seamonkey), and Ubuntu (linux-aws-5.4 and linux-ibm).

Linus has released 6.1-rc1 and closed themerge window for this development cycle.

Google has announcedthe existence of yet another new operating system, called KataOS, aimed atthe creation of secure embedded systems.

The6.0.2,5.19.16,5.15.74,5.10.148, and5.4.218stable kernel updates have all been released. Among other things, theseupdates contain the fixes for the recently disclosed WiFi vulnerabilities.

Software patents affect our systems in many ways, but perhaps moststrongly in the area of codecs — code that creates or plays back audioor video that has been compressed using covered algorithms. For thisreason, certain formats have simply been unplayable on many Linuxdistributions — especially those backed by companies that are bigenough to be worth suing — without installing add-on software fromthird-party repositories. One might think that this problem could beworked around by purchasing hardware that implements the patented algorithms,but recent activity in the Fedora and openSUSE communities shows that lifeis not so simple.

Security updates have been issued by Debian (chromium), Fedora (dbus, dhcp, expat, kernel, thunderbird, vim, and weechat), Mageia (libofx, lighttpd, mediawiki, and python), Oracle (.NET 6.0 and .NET Core 3.1), Slackware (python3), SUSE (chromium, kernel, libosip2, python-Babel, and python-waitress), and Ubuntu (gThumb, heimdal, linux-aws, linux-gcp-4.15, linux-aws-hwe, linux-gcp, linux-oracle-5.4, linux-raspi, linux-raspi-5.4, postgresql-9.5, and xmlsec1).