LWN.net

As of this writing, 5,392 non-merge changesets have been pulled into themainline repository for the 4.17 release. The 4.17 merge window is thusoff to a good start, but it is far from complete. The changes pulled thusfar cover a wide part of the core kernel as well as the networking, driver,and filesystem subsystems.

Security updates have been issued by Arch Linux (drupal), Debian (openjdk-7), Fedora (exempi, gd, and tomcat), SUSE (python-paramiko), and Ubuntu (kernel, libvncserver, linux, linux-aws, linux-kvm, linux-raspi2, linux-snapdragon, linux-lts-trusty, and linux-raspi2).

The LWN.net Weekly Edition for April 5, 2018 is available.

It has been known for quite some time that Python 2 will reach its endof life in 2020—after being extended by five years from its original 2015expiry. After that, there will be no support, bug fixes, or security patches forPython 2, at least from the Python Software Foundation and the coredevelopers. Some distributions will need to continue to support the finalPython 2 release, however, since their support windows extend pastthat date; the enterprise and long-term support distributions willlikely be supporting it well into the 2020s and possibly beyond. But evenshorter-support-cycle distributions need to consider their plan for asweeping change of this sort—in less than two years.

Security updates have been issued by Debian (apache2, ldap-account-manager, and openjdk-7), Fedora (libuv and nodejs), Gentoo (glibc and libxslt), Mageia (acpica-tools, openssl, and php), SUSE (clamav, coreutils, and libvirt), and Ubuntu (kernel, libraw, linux-hwe, linux-gcp, linux-oem, and python-crypto).

The Linux Foundation and Nitrokey have announceda program whereby anybody who appears in the kernel's MAINTAINERS file orwho has a kernel.org email address can obtain a free Nitrokey Start crypto card. Theintent, of course, is that kernel developers will use these devices tosafeguard their GnuPG keys and, as a result, improve the security of thekernel development process as a whole. "A digital smartcard tokenlike Nitrokey Start contains a cryptographic chip that is capable ofstoring private keys and performing crypto operations directly on the tokenitself. Because the key contents never leave the device, the operatingsystem of the computer into which the token is plugged in is not able toretrieve the private keys themselves, therefore significantly limiting theways in which the keys can be leaked or stolen."See this LWN article for a look at crypto cards.

One of the trickiest aspects to concurrency in the kernel is waiting for aspecific event to take place. There is a wide variety of possible events,including a process exiting, the last reference to a data structure goingaway, a device completing an operation, or a timeout occurring.Waiting is surprisingly hard to get right — race conditions abound to trapthe unwary — so the kernel hasaccumulated a large set of wait_event_*() macros to make the task easier. Anattempt to add a new one, though, has led to the generalization of specifictypes of waits for 4.17.

Many large institutions, especially government agencies, would like todistribute their software—including the software of the vendors with whomthey contract—as free software. They have a variety of reasons, rangingfrom the hope that opening the code will boost its use, all the way toa mature understanding of the importance of community, transparency, andfreedom. There are special steps institutions can take to help ensure success,some stemming from best practices performed by many free-software projectsand others specific to large organizations. At the 2018 LibrePlanet conference,Cecilia Donnelly laid out nine principles for the successful creation and maintenance of a software project under thesecircumstances.

Security updates have been issued by Debian (beep and jruby), Fedora (libvncserver), and Ubuntu (openjdk-7 and openjdk-8).

Version 2.17.0 of the Git source-code management system is out. Itincludes a long list of relatively minor tweaks. "Since Git 1.7.9,'git merge' defaulted to --no-ff (i.e. even when the side branch beingmerged is a descendant of the current commit, create a merge commit insteadof fast-forwarding) when merging a tag object. This was appropriatedefault for integrators who pull signed tags from their downstreamcontributors, but caused an unnecessary merges when used by downstreamcontributors who habitually 'catch up' their topic branches with taggedreleases from the upstream. Update 'git merge' to default to --no-ff onlywhen merging a tag object that does *not* sit at its usual place inrefs/tags/ hierarchy, and allow fast-forwarding otherwise, to mitigate theproblem."

The GnuCash 3.0 release is out. "The headline item for this release is that GnuCash now uses the Gtk+-3.0Toolkit and the WebKit2Gtk API. This change was forced on us by some majorLinux distributions dropping support for the WebKit1 API." Thisrelease also includes some new reports, a rewritten CSV importer, andmore. LWN looked at GnuCash from abusiness-accounting point of view in August 2017.

The OpenBSD 6.3 release is out. "The release was scheduled for April15, but since all the components are ready ahead of schedule it is beingreleased now." This release includes mitigation for the Meltdownvulnerability but not for Spectre on x86.

The UEFI secure boot mechanism is intended to protect the system againstpersistent malware threats — unpleasant bits of software attached to theoperating system or bootloader that will survive a reboot. While Linuxhas supported secure boot for some time, proponents have long said thatthis support is incomplete in that it is still possible for the root userto corrupt the system in a number of ways. Patches that attempt toclose this hole have been circulating for years, but they have beencontroversial at best. This story may finally come to a close, though, ifLinus Torvalds accepts the "kernel lockdown" patch series during the 4.17merge window.

Security updates have been issued by Debian (dovecot, irssi, libevt, libvncserver, mercurial, mosquitto, openssl, python-django, remctl, rubygems, and zsh), Fedora (acpica-tools, dovecot, firefox, ImageMagick, mariadb, mosquitto, openssl, python-paramiko, rubygem-rmagick, and thunderbird), Mageia (flash-player-plugin and squirrelmail), Slackware (php), and Ubuntu (dovecot).

Linus has released the 4.16 kernel, asexpected. "We had a number of fixes and cleanups elsewhere, but noneof it made me go 'uhhuh, better let this soak for another week'".Some of the headline changes in this release include initial support forthe Jailhousehypervisor, the usercopy whitelistinghardening patches, some improvements to the deadline scheduler and, ofcourse, a lot of Meltdown and Spectre mitigation work.

The stable kernel update machine continues to generate releases:4.15.15,4.14.32,4.9.92, and4.4.126 are now available with another setof important fixes.

Terminals have a special place in computing history, surviving alongwith the command line in the face of the rising ubiquity of graphicalinterfaces. Terminal emulators have replacedhardwareterminals, which themselves were upgrades from punched cards and toggle-switch inputs. Modern distributions now ship with asurprising variety of terminal emulators. While some people may behappy with the default terminal provided by their desktop environment,others take great pride at using exotic software for running theirfavorite shell or text editor. But as we'll see in this two-part series,not all terminals are created equal: they vary wildly in terms of functionality, size, andperformance.

Security updates have been issued by Debian (memcached, openssl, openssl1.0, php5, thunderbird, and xerces-c), Fedora (python-notebook, slf4j, and unboundid-ldapsdk), Mageia (kernel, libvirt, mailman, and net-snmp), openSUSE (aubio, cacti, cacti-spine, firefox, krb5, LibVNCServer, links, memcached, and tomcat), Slackware (ruby), SUSE (kernel and python-paramiko), and Ubuntu (intel-microcode).

The kernel development community has consistently resisted adding anyformal notion of what a "container" is to the kernel. While the neededbuilding blocks (namespaces, control groups, etc.) are provided, it is upto user space to assemble the pieces into the sort of containerimplementation it needs. This approach maximizes flexibility and makes itpossible to implement a number of different container abstractions, but italso can make it hard to associate events in the kernel with the containerthat caused them. Audit container IDs are an attempt to fix that problemfor one specific use case; they have not been universally well received inthe past, but work on this mechanism continues regardless.

The Rust team has announcedthe release of Rust 1.25.0. "The last few releases have beenrelatively minor, but Rust 1.25 contains a bunch of stuff! The first one isstraightforward: we’ve upgraded to LLVM 6from LLVM 4. This has a number of effects, a major one being a step closerto AVR support." See the releasenotes for details.

Greg Kroah-Hartman has announced the release of the 4.15.14, 4.14.31, 4.9.91, and 4.4.125 stable kernels. As usual, theycontain a wide array of fixes throughout the kernel tree; users shouldupgrade.

Security updates have been issued by Debian (drupal7, graphicsmagick, libdatetime-timezone-perl, thunderbird, and tzdata), Fedora (gd, libtiff, mozjs52, and nmap), Gentoo (thunderbird), Red Hat (openstack-tripleo-common, openstack-tripleo-heat-templates and sensu), SUSE (kernel, libvirt, and memcached), and Ubuntu (icu, librelp, openssl, and thunderbird).

The LWN.net Weekly Edition for March 29, 2018 is available.

It has only been a few years since DNF replaced Yum as the default Fedorapackage-management tool; that was done for Fedora 22 in 2015, thoughDNF had been available for several earlier Fedora releases. Since thattime, DNF development has proceeded; it started a move from Python/C to all C in2016 and has made multiple releases over the years. From an outsider'sperspective, no major changes seem necessary, which makes the announcementof DNF 3, and a move to C++, a bit surprising to some.

We may need Tor, "the onion router",more than we ever imagined. Authoritarian states are blocking more and more websites and snoopingon their populations online—even routine tracking of our onlineactivities can reveal information that can be used to underminedemocracy. Thus, there was strong interest in the "State of the Onion"panel at the 2018 LibrePlanet conference, wherefour contributors to the Tor project presented a progress update covering thepast few years.Subscribers can read on for a report on the panel by guest author Andy Oram.

The Drupal security team has sent out a "highly critical"alert: "A remote code execution vulnerability exists withinmultiple subsystems of Drupal 7.x and 8.x. This potentially allowsattackers to exploit multiple attack vectors on a Drupal site, which couldresult in the site being completely compromised." This seems worthavoiding; updating to the current version is the way to do that. There isan FAQ pagewith a little more information.

Per Bothner has released DomTerm 1.0. Since DomTerm was coveredhere in January 2016, many features have been added or enhanced. (Seethis articleon opensource.com.)DomTerm is a mostly-xterm-compatible terminal emulator, but the output canbe graphics, rich text, and other html, so it is suitable as a REPL for aprogram like gnuplot. Other major features include screen/tmux-style tiling and detachablesessions, readline-style input editing (integrated with mouse andclipboard), and opening an editor when clicking an error message.

The security-focused distribution Qubes OS has releasedversion 4.0. "This release delivers on the features we promised inour announcementof Qubes 4.0-rc1, with some course corrections along the way, such asthe switch from HVM to PVH for most VMs in response to Meltdownand Spectre. For more details, please see the full Release Notes."

Many people have seen music visualizations before, whether in a musicplayer on their computer, at a live concert, or possibly on a home stereosystem. Those visualizations may have been generated using the open-sourcemusic-visualization software library that is part of projectM.Software-based abstract visualizers first appeared along with early MP3 music players as asort of nifty thing to watch along with listening to your MP3s. One ofthe most powerful and innovative of these was a plugin for Winamp known asMilkDrop, which wasdeveloped by a Nullsoft (and later NVIDIA) employee named Ryan Geiss. The plugin wasextensible by using visualizationequation scripts (also known as "presets").Subscribers can read on for a look at projectM by guest author (andprojectM maintainer) Mischa Spiegelmock.

Security updates have been issued by CentOS (slf4j), Debian (firefox-esr, mupdf, net-snmp, and samba), Fedora (apache-commons-compress, calibre, chromium, glpi, kernel, libvncserver, libvorbis, mozjs52, ntp, slurm, sqlite, and wireshark), openSUSE (librelp), SUSE (librelp, LibVNCServer, and qemu), and Ubuntu (firefox and zsh).

Kernel developers go to some lengths to mark read-only data so that it canbe protected by the system's memory-management unit.Memory that cannot be changed cannot be altered by an attacker to corrupt thesystem. But the kernel's mechanisms for managing read-only memory do notwork for memory that must be initialized after the initial system bootstraphas completed. A patch set from Igor Stoppaseeks to change that situation by creating a new API just forlate-initialized read-only data.

Kubernetes 1.10 has been released. "This newest version stabilizes features in 3 key areas, including storage, security, and networking. Notable additions in this release include the introduction of external kubectl credential providers (alpha), the ability to switch DNS service to CoreDNS at install time (beta), and the move of Container Storage Interface (CSI) and persistent local volumes to beta."

Techdirt reportsthat the US Court of Appeals for the Federal Circuit (CAFC) has resurrectedOracle's copyright claim against Google for its use of the Java APIs inAndroid. "Honestly, the most concerning part of the whole thing ishow much of a mess CAFC has made of the whole process. The court ruledcorrectly originally that APIs are not subject to copyright. CAFC threwthat out and ordered the court to have a jury determine the fair usequestion. The jury found it to be fair use, and even though CAFC hadordered the issue be heard by a jury, it now says 'meh, we disagree withthe jury.' That's... bizarre."

Security updates have been issued by Debian (firefox-esr, irssi, and librelp), Gentoo (busybox and plib), Mageia (exempi and jupyter-notebook), openSUSE (clamav, dhcp, nginx, python-Django, python3-Django, and thunderbird), Oracle (slf4j), Red Hat (slf4j), Scientific Linux (slf4j), Slackware (firefox), SUSE (librelp), and Ubuntu (screen-resolution-extra).

The 4.16 development cycle is shaping up to be arelatively straightforward affair with little in the way of known problemsand a probable release after nine weeks of work. In comparison to the wildride that was 4.15, 4.16 looks positively calm. Even so, there is a lotthat has happened this time around; read on for a look at who contributedto this release, with a brief digression into stable kernel updates.

The Free Software Foundation (FSF) announcedthe winners of the 2017 Free Software Awards during LibrePlanet."Public Lab is a community and non-profit organization with the goalof democratizing science to address environmental issues. Theircommunity-created tools and techniques utilize free software and low-costdevices to enable people at any level of technical skill to investigateenvironmental concerns." The organization received the Award forProjects of Social Benefit. Karen Sandler, the Executive Director of theSoftware Freedom Conservancy, received the Award for the Advancement ofFree Software.

Security updates have been issued by Arch Linux (bchunk, thunderbird, and xerces-c), Debian (freeplane, icu, libvirt, and net-snmp), Fedora (monitorix, php-simplesamlphp-saml2, php-simplesamlphp-saml2_1, php-simplesamlphp-saml2_3, puppet, and qt5-qtwebengine), openSUSE (curl, libmodplug, libvorbis, mailman, nginx, opera, python-paramiko, and samba, talloc, tevent), Red Hat (python-paramiko, rh-maven35-slf4j, rh-mysql56-mysql, rh-mysql57-mysql, rh-ruby22-ruby, rh-ruby23-ruby, and rh-ruby24-ruby), Slackware (thunderbird), SUSE (clamav, kernel, memcached, and php53), and Ubuntu (samba and tiff).

The 4.16-rc7 prepatch is out; it'sprobably the last one. "I'm still not *planning*on an rc8 this release, because while rc7 is bigger than usual,nothing in here makes me go 'Hmm, maybe we should delay the release'.But let's see what happens this upcoming week - if next Sunday comesaround, and there's lots of new stuff, I'll reconsider then."

The4.15.13,4.14.30,4.9.90,4.4.124,and 3.18.102have all been released; each contains a relatively large set of importantfixes and updates.

Here's thesecond part of Daniel Stone's series on recent improvements inlow-level graphics support. "The end result of all this work is thatwe have been able to eliminate the magic side channels which used toproliferate, and lay the groundwork for properly communicating thisinformation across multiple devices as well. Devices supporting ARM's AFBCcompression format are just beginning to hit the market, which share asingle compression format between video decoder, GPU, and displaycontroller. We are also beginning to see GPUs from different vendors sharetiling formats, in order to squeeze the most performance possible fromhybrid GPU systems."

Security updates have been issued by Debian (adminer, isc-dhcp, kamailio, libvorbisidec, plexus-utils2, and simplesamlphp), Fedora (exim and glibc-arm-linux-gnu), Mageia (sqlite3), openSUSE (Chromium, kernel, and qemu), SUSE (memcached), and Ubuntu (sharutils).

Energy-aware scheduling — running a system's workload in a way thatminimizes the amount of energy consumed — has been a topic of activediscussion and development for some time; LWN first covered the issue at the beginning of 2012.Many approaches have been tried during the intervening years, but little inthe way of generalized energy-aware scheduling work has made it into themainline. Recently, a new patch set wasposted by Dietmar Eggemann that only tries to address one aspect of the problem; perhaps the problem domainhas now been simplified enough that this support can finally be merged.

Yet another new crop of stable kernels has been released: 4.9.89, 4.4.123, and 3.18.101. Each contains a rather large set ofchanges all over the kernel tree; users of those series should upgrade.

Version 4.0of the Krita drawing tool has been released; see thisarticle for a summary of the new features in this release."Krita 4.0 will use SVG on vector layers by default, instead of theprior reliance on ODG. SVG is the most widely used open format for vectorgraphics out there. Used by 'pure' vector design applications, SVG on Kritacurrently supports gradients and transparencies, with more effects comingsoon."

Security updates have been issued by Arch Linux (lib32-libvorbis), Debian (exempi and polarssl), Gentoo (collectd and webkit-gtk), openSUSE (postgresql96), SUSE (qemu), and Ubuntu (libvorbis).

The LWN.net Weekly Edition for March 22, 2018 is available.

"Syzbot" is an automated system that runs the syzkaller fuzzer on thekernel and reports the resulting crashes. Dmitry Vyukov has announced theavailability of a web sitedisplaying the outstanding reports. "The dashboard shows info about active bugs reported by syzbot. Thereare ~130 active bugs and I think ~2/3 of them are actionable (stillhappen and have a reproducer or are simple enough to debug)."

While updating kernels frequently is generally considered a security bestpractice, there are many installations that are unable to do so for avariety of reasons. That means running with some number of knownvulnerabilities (along with an unknown number of unknown vulnerabilities, ofcourse), so some way to detect and stop exploits for those flaws may bedesired. That is exactly what the Linux Kernel Runtime Guard (LKRG)is meant to do.

It is an increasingly poorly kept secret that, underneath the hood ofthe components that most of us view as "hardware", there is a great deal ofproprietary software. This code, written by anonymous developers, rarelysees the light of day; as a result, it tends to have all of the pathologiesassociated with software that nobody can either review or fix. The 2018Embedded Linux Conference saw an announcement for a new project that, with luck, will change thatsituation, at least for one variety of hardware: audio devices.

Version5.4 of the RawTherapee image-processing tool is out. New featuresinclude a new histogram-matching tool, a new HDR tone-mapping tool, anumber of user-interface and performance improvements, and quite a bitmore.