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Security updates have been issued by Oracle (bind, kernel, libcroco, nss and nspr, qemu-kvm, spice and spice-gtk, and squid) and SUSE (kernel).

One of the key rules of Linux kernel development is that the ABI betweenthe kernel and user space cannot be broken; any change that breakspreviously working programs will, outside of exceptional circumstances, bereverted. The rule seems clear, but there are ambiguities when it comes todetermining just what constitutes the kernel ABI; tracepoints are a perennial example of this. A recentdiscussion has brought another one of those ambiguities to light: the on-disk format of Linuxfilesystems.

Security updates have been issued by Debian (activemq, golang-go.crypto, packagekit, and sympa), Fedora (php and xen), Red Hat (bind, kernel, and qemu-kvm), SUSE (qemu), and Ubuntu (golang-github-seccomp-libseccomp-golang and spice).

The LWN.net Weekly Edition for October 8, 2020 is available.

In unusually stark terms, Mozilla is trying to rally thetroops to take back the internet from the forces of evil—or at least "misinformation,corruption and greed"—that have overtaken it. In aSeptember 30 blogpost, the organization behind the Firefox web browserwarned that "the internet needs our love". While there is lots tocelebrate about the internet, it is increasingly under threat fromvarious types of bad actors, so Mozilla is starting a campaign to try topush back against those threats.

The first preview of Ruby version 3.0 was released on September 25. It includes better support for type checking, additional language features, and two new experimental features: a parallel execution mechanism called Ractor, and Scheduler, which provides concurrency improvements.

Stable kernels 5.8.14, 5.4.70, and 4.19.150 have been released with someimportant fixes. Users should upgrade.

Security updates have been issued by Arch Linux (brotli, lib32-brotli, lib32-zeromq, samba, yaws, and zeromq), Debian (php7.0, puma, sane-backends, thunderbird, and tigervnc), Fedora (ghc-cmark-gfm, ghc-hakyll, gitit, pandoc, pandoc-citeproc, and patat), openSUSE (kdeconnect-kde and perl-DBI), Oracle (kernel), Red Hat (chromium-browser and spice and spice-gtk), SUSE (hexchat and nodejs8), and Ubuntu (vino).

The Zig programming language is arelatively recent entrant into the "systems programming" realm; it looksto interoperate with C, while adding safety features without sacrificingperformance. The language has been gaining some attention of late and hasannouncedprogress toward a Zig compiler written in Zig in September. Thatchange will allow LLVM to become an optional component, which will be a big step forward for the"maturity and stability" of Zig.

Security updates have been issued by Fedora (chromium, libproxy, mumble, and thunderbird), openSUSE (perl-DBI), Red Hat (qemu-kvm-rhev, rh-mariadb102-mariadb and rh-mariadb102-galera, rh-maven35-jackson-databind, spice and spice-gtk, and unbound), SUSE (gnutls, java-1_7_0-openjdk, openssl1, and perl-DBI), and Ubuntu (brotli, cyrus-imapd, openconnect, opendmarc, python-urllib3, ruby-rack-cors, spice, tika, and yaws).

Version 3.9 of the Python programming language has been released. The changelog, "What's New in Python 3.9" document, and our recent article have lots more information on the release."Maintenance releases for the 3.9 series will follow at regular bi-monthly intervals starting inlate November of 2020.OK, boring! Where is Python 4?Not so fast! The next release after 3.9 will be 3.10. It will be an incremental improvement over3.9, just as 3.9 was over 3.8, and so on."

At Akademy 2020, theannual KDE conference that was held virtually this year, KDE developer NateGraham delivered a talk entitled "Visions of the Future" (YouTube video) about thepossible future of KDE on commercial products. Subtitled "Plasma sold on retail hardware — lots of it", the session concentrated on ways tomake KDE applications (and the Plasma desktop) the defaultenvironment on hardware sold to the general public. The proposal includes creating anofficial KDE distribution with a hardware certification program anddirectly paying developers.

U-Boot (the Universal Boot Loader) v2020.10 is out. "With this releasewe have a number of 'please migrate to DM [Driver Model [PDF]]' warnings that are now 1 yearpast their warning date, and well past 1 year of those warnings beingprinted. It's getting up there on my TODO list to see if removingfeatures or boards in these cases is easier."

Security updates have been issued by Debian (libvirt, snmptt, squid3, and xen), Fedora (chromium, libproxy, mumble, samba, and xawtv), openSUSE (bcm43xx-firmware, dpdk, grafana, nodejs12, python-pip, xen, and zabbix), Oracle (thunderbird), Red Hat (cockpit-ovirt, imgbased, redhat-release-virtualization-host, redhat-virtualization-host and qemu-kvm-rhev), and SUSE (perl-DBI).

The eighth and presumably final 5.9prepatch is out for testing. "So things have been pretty calm, and rc8 is fairly small. I'm stillwaiting for a networking pull with some fixes, so it's not like Icould have made a final 5.9 release even if I had wanted to, but therewas nothing scary going on this past week, and it all feels ready fora final 5.9 next weekend."

The Document Foundation (TDF) was formed in2010 as a home for the newly created LibreOffice project; it has just celebratedits tenth anniversary. As it begins its second decade, though, TDF isshowing some signs of strain. Evidence of this could be seen in the disagreement over a five-year marketingplan in July. More recently, the TDF membership committee sent an open letter to the board of directorsdemanding more transparency and expressing fears of conflicts of interestwithin the board. Now the situation has advanced with one of the TDF'slargest contributing companies announcing that it will be moving some ofits work out of the foundation entirely.

Security updates have been issued by Debian (jruby and ruby2.3), Fedora (crun, pdns, and podman), openSUSE (go1.14 and kernel), Oracle (qemu-kvm and virt:ol), Red Hat (qemu-kvm-ma and thunderbird), SUSE (nodejs10, nodejs12, perl-DBI, permissions, and xen), and Ubuntu (ntp).

The Software Freedom Conservancy has announced that it is embarking on "a new strategy toward improving compliance and the freedom of users of devices that contain Linux-based systems". That includes GPL enforcement, an effort to create alternative firmware for embedded Linux devices, and collaboration with other organizations "to promote copyleft compliance as a feature for consumers to protect their privacy and get more out of their devices". The work is being sponsored by an initial $150,000 grant from Amateur Radio Digital Communications (ARDC). "We take this holistic approach because compliance is not an end in itself, but rather a lever to help people advance technology for themselves and the world. Bradley Kuhn, Conservancy’s Policy Fellow and Hacker-in-Residence remarked: 'GPL enforcement began as merely an education process more than twenty years ago. We all had hoped that industry-wide awareness of copyleft’s essential role in spreading software freedom would yield widespread, spontaneous compliance. We were simply wrong about that. Today, we observe almost universal failure in compliance throughout the (so-called) Internet of Things (IoT) market. Only unrelenting enforcement that holds companies accountable can change this abysmal reality. ARDC, a visionary grant-maker, recognizes the value of systemic enforcement that utilizes the legal system to regain software freedom. That process also catalyzes community-led projects to build liberated firmware for many devices.'"

On his blog, David Edmundson writes about a new optional mechanism for starting up the KDE Plasma desktop using systemd. "Another big motivating factor was the ability for customisation. The root of Plasma's startup is very hardcoded. What if you want to run krunner with a different environment variable set? or have a script run every time plasmashell restarts, or show a UI after kwin is loaded but before plasma shell to perform some user setup? You can edit the code, but that's not easy and you're very much on your own.Systemd provides that level of customisation; both at a distro or a user level out of the box. From our POV for free."

The 5.8.13, 5.4.69, 4.19.149, 4.14.200, and 4.4.238 stable kernels have been released.Note that 4.9.238 was in the review cycle with the rest of these kernelsbut needed a respindue to some test failures, so it will be released on or after October 3. Asusual, all five of the released kernels have fixes throughout the tree;users should upgrade.Update: Apparently October 3 came early for Greg Kroah-Hartmanbecause 4.9.238 has now been released.

The ability to execute the contents of a file is controlled by theexecute-permission bits — some of the time. If a given file contains codethat can be executed by an interpreter — such as shell commands or code in alanguage like Perl or Python, for example — there are easy ways to run the interpreter onthe file regardless of whether it has execute permission enabled or not.Mickaël Salaün has been working on tightening up the administrator'scontrol over execution by interpreters for some time, but has struggled tofind an acceptable home for this feature. His latest attempt takes theform of a new system call named trusted_for().

Security updates have been issued by Debian (ruby-json-jwt and ruby-rack-cors), Fedora (xen), SUSE (aspell and tar), and Ubuntu (ruby-gon, ruby-kramdown, and ruby-rack).

The LWN.net Weekly Edition for October 1, 2020 is available.

SELinux is asecurity mechanism with a lot of ability to restrict user-space compromisesin various useful ways. It has also generally been considered aheavyweight option that is not suitable for more resource-restrictedsystems like wireless routers. Undeterred by this perception, some OpenWrt developers are adding SELinux asan option for protecting the distribution, which targets embedded devices.

Keeping device firmware up-to-date can be a challenge for end users. Firmware updates are often important for correct behavior, and they can have security implications as well. The Linux Vendor Firmware Service (LVFS) project is playing an increasing role in making firmware updates more straightforward for both end users and vendors; LVFS just announced its 20-millionth firmware download. Since even a wireless mouse dongle can pose a security threat, the importance of simple, reliable, and easily applied firmware updates is hard to overstate.

Version 4.16.0 of the RPM package manager has been released. "Thisturned out to be a much bigger release than anticipated with severalgroundbreaking new features, despite finally being back to annual cyclealmost to date." Highlights include new database backends, macro and%if expressions including ternary operator and native version comparison,optional MIME type based file classification, new version parsing andcomparison API in C and Python, license clarification, and more. The release notes have more details.

Security updates have been issued by Arch Linux (chromium, firefox, libvirt, and podman), Debian (firefox-esr and nss), Gentoo (bitcoind, chromium, cifs-utils, gpsd, libuv, and xen), Mageia (firefox, gnutls, mediawiki, samba, and Thunderbird), openSUSE (brotli and cifs-utils), Red Hat (audiofile, bluez, cloud-init, cpio, cups, curl, dbus, dnsmasq, e2fsprogs, evince and poppler, exiv2, expat, firefox, fontforge, freeradius, freerdp, glib2 and ibus, glibc, httpd, hunspell, ipa, kernel, kernel-rt, libcroco, libexif, libmspack, libpng, librabbitmq, libsndfile, libsrtp, libssh2, libtiff, libvirt, libvpx, libwmf, libxml2, libxslt, mariadb, mod_auth_openidc, NetworkManager, nss and nspr, okular, OpenEXR, openldap, openwsman, pcp, python, python-pillow, python3, qemu-kvm, qemu-kvm-ma, qt5-qtbase, samba, SDL, spamassassin, squid, subversion, systemd, tigervnc, tomcat, unoconv, and webkitgtk4), SUSE (bcm43xx-firmware, nodejs8, pdns, python-pip, and xen), and Ubuntu (libapreq2, netqmail, samba, and tomcat6).

Fish (the "friendly interactiveshell") hasthe explicit goal of being more user-friendly than other shells.It features a modern command-line interface with syntax highlighting, tabcompletion, and auto-suggestions out of the box(all with no configuration required). Unlike many of its competitors, it doesn't careabout being POSIX-compliant but attempts to blaze its own path. Since ourlast look at the project, way back in 2013, ithas seen lots of new releases with features, bug fixes, and refinementsaimed at appealing to a wide range of users. Some of the biggest additions landed in the3.0 release, butwe will also describe some other notable changes from version 2.1 up throughlatest version.

Security updates have been issued by Debian (firefox-esr and mediawiki), openSUSE (firefox, libqt5-qtbase, and rubygem-actionpack-5_1), Red Hat (qemu-kvm, qemu-kvm-ma, and virt:rhel), SUSE (dpdk, firefox, and go1.15), and Ubuntu (dpdk, imagemagick, italc, libpgf, libuv1, pam-python, squid3, ssvnc, and teeworlds).

Recently, the Mercurial project has been discussing its plans to migrate away from the compromised SHA-1 hashing algorithm in favor of a more secure alternative. So far, the discussion is in the planning stages of algorithm selection and migration strategy, with a general transition plan for users. The project, for the moment, is favoring the BLAKE2 hashing algorithm.

OpenSSH 8.4 is out. The SHA-1 algorithm is deprecated and the "ssh-rsa"public key signature algorithm will be disabled by default "in anear-future release." They note that it is possible to performchosen-prefix attacks against the SHA-1 algorithm for less than USD$50K.

Security updates have been issued by Debian (curl, libdbi-perl, linux-4.19, lua5.3, mediawiki, nfdump, openssl1.0, qt4-x11, qtbase-opensource-src, ruby-gon, and yaws), Fedora (grub2, libxml2, perl-DBI, singularity, and xawtv), Mageia (cifs-utils, kio-extras, libproxy, mbedtls, nodejs, novnc, and pdns), openSUSE (bcm43xx-firmware, chromium, conmon, fuse-overlayfs, libcontainers-common, podman, firefox, libqt4, libqt5-qtbase, openldap2, ovmf, pdns, rubygem-actionpack-5_1, and tiff), SUSE (firefox, go1.14, ImageMagick, and libqt5-qtbase), and Ubuntu (firefox, gnuplot, libquicktime, miniupnpd, ruby-sanitize, and sudo).

The 5.9-rc7 kernel prepatch is out fortesting. "But while I do now know of any remaining gating issues any more, thefixes came in fairly late. So unless I feel insanely optimistic and/ora burning bush tells me that everything is bug-free, my plan right nowis that I'll do another rc next Sunday rather than the final 5.9release. And btw, please no more burning bushes. We're kind ofsensitive about those on the West coast right now."

The5.8.12,5.4.68, and4.19.148stable kernels have been released; each contains another set of importantfixes.

It has only been a few months since the Emacs community went through an extended discussion on how to make the Emacs editor "popularagain". As the community gears up for the Emacs 28 development cycle,(after the Emacs27.1 release in August)that discussion has returned with a vengeance. The themes of thisdiscussion differ somewhat from the last; developers are concerned aboutmaking Emacs — an editor with decades of history — seem "modern" to attractnew users.

Version 5.0 of theCalibre electronic-book manager has been released. "There has been alot of work on the calibre E-book viewer. It now supports Highlighting. Thehighlights can be colors, underlines, strikethrough, etc. and have addednotes. All highlights can be both stored in EPUB files for easy sharing andcentrally in the calibre library for easy browsing. Additionally, theE-book viewer now supports both vertical and right-to-left text."Another significant change is a port to Python 3; that was a necessarychange but it means that there are a number of plugins that have not yetbeen ported and thus won't work. The status of many plugins can be foundon thispage.

Security updates have been issued by Debian (rails), openSUSE (chromium, jasper, ovmf, roundcubemail, samba, and singularity), Oracle (firefox), SUSE (bcm43xx-firmware, firefox, libqt5-qtbase, qemu, and tiff), and Ubuntu (aptdaemon, atftp, awl, packagekit, and spip).

The set_fs() function dates back to the earliest days of the Linuxkernel; it is a key part of the machinery that keeps user-space andkernel-space memory separated from each other. It is also easy to misuseand has been the source of various security problems over the years; kerneldevelopers have long wanted to be rid of it. They won't completely get theirwish in the 5.10 kernel but, as the result of work that has been quietlyprogressing for several months, the end of set_fs() will be easilyvisible at that point.

Version 13 of the PostgreSQL database management system is out."PostgreSQL 13 includes significant improvements to its indexing and lookupsystem that benefit large databases, including space savings and performancegains for indexes, faster response times for queries that use aggregates orpartitions, better query planning when using enhanced statistics, and more.Along with highly requested features like parallelized vacuuming andincremental sorting, PostgreSQL 13 provides a better data managementexperience for workloads big and small, with optimizations for dailyadministration, more conveniences for application developers, and securityenhancements."

Security updates have been issued by Fedora (firefox, libproxy, mbedtls, samba, and zeromq), openSUSE (chromium and virtualbox), Red Hat (firefox and kernel), SUSE (cifs-utils, conmon, fuse-overlayfs, libcontainers-common, podman, libcdio, python-pip, samba, and wavpack), and Ubuntu (rdflib).

The LWN.net Weekly Edition for September 24, 2020 is available.

It is a pretty rare event to see a nearly 21-year-old bug be addressed—manyprojects are nowhere near that old for one thing—but that is just what hasoccurred for the Mozilla Thunderbird emailapplication. An enhancementrequest filed at the end of 1999 asked for a plugin to support email encryption, but it has mostlylanguished since. The Enigmail plugin did comealong to fill the gap by providing OpenPGP support using GNU Privacy Guard (GnuPG or GPG), but wasnever part of Thunderbird.As part of Thunderbird 78,though, OpenPGP is now fully supported within the mail user agent(MUA).

Stable kernels 5.8.11, 5.4.67, 4.19.147, 4.14.199, 4.9.237, and 4.4.237 have been released with importantfixes. Users should upgrade.

Disabling SELinuxis, perhaps sadly in some ways, a time-honored tradition for users of Fedora, RHEL, and other distributions that feature thesecurity mechanism. Over the years, SELinux has gotten easier to toleratedue to the hard work of its developers and the distributions, but there arestill third-party packages that recommend or require disabling SELinux inorder to function. Up until fairly recently, the kernel has supporteddisabling SELinux at run time, but that mechanism has been deprecated—inpart due to another kernel security feature. Now Fedora is planningto eliminate the ability to disable SELinux at run time in Fedora 34, which sparkedsome discussion in its devel mailing list.

Security updates have been issued by openSUSE (libetpan, libqt4, lilypond, otrs, and perl-DBI), Red Hat (kernel-rt), Slackware (seamonkey), SUSE (grafana, libmspack, openldap2, ovmf, pdns, rubygem-actionpack-5_1, and samba), and Ubuntu (debian-lan-config, ldm, libdbi-perl, and netty-3.9).

Python 3.9.0rc2 was released on September 17, with the final version scheduled for October 5, roughly a year after the release of Python 3.8. Python 3.9 will come with new operators for dictionary unions, a new parser, two string operations meant to eliminate some longstanding confusion, as well as improved time-zone handling and type hinting. Developers may need to do some porting for code coming from Python 3.8 or earlier, as the new release has removed several previously-deprecated features still lingering from Python 2.7.

The functiontracer (ftrace) subsystem has become an essential part of the kernel'sintrospection tooling. Like many kernel subsystems, ftrace uses a ring buffer toquickly communicate events to user space; those events include a timestamp toindicate when they occurred. Until recently, the design of the ring bufferhas led to the creation of inaccurate timestamps when events are generatedfrom interrupt handlers. That problem has now been solved; read on for anin-depth discussion of how this issue came about and the form of itssolution.

Linux Journal has returnedunder the ownership of Slashdot Media. "As Linux enthusiasts and long-time fans of Linux Journal, we were disappointed to hear about Linux Journal closing its doors last year. It took some time, but fortunately we were able to get a deal done that allows us to keep Linux Journal alive now and indefinitely. It's important that amazing resources like Linux Journal never disappear."

Firefox 81.0 is out. This version allows you to control media from thekeyboard or headset, introduces the Alpenglow theme, adds ArcoForm support tofill in, print, and save supported PDF forms, and more. See the release notesfor details.

Security updates have been issued by Mageia (mysql-connector-java), openSUSE (chromium, curl, libqt4, and singularity), Red Hat (bash and kernel), SUSE (python-pip and python3), and Ubuntu (busybox, ceph, freeimage, libofx, libpam-tacplus, linux, linux-aws, linux-aws-hwe, linux-azure, linux-azure-4.15, linux-gcp, linux-gcp-4.15, linux-gke-4.15, linux-hwe, linux-oem, linux-oracle, linux-raspi2, linux-snapdragon, linux, linux-azure, linux-gcp, linux-oracle, novnc, and tnef).