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The 4.4.117, 4.9.83, 4.14.21, and 4.15.5 stable kernels have been released.They contain a large number of updates throughout the tree; users shouldupgrade.

Security updates have been issued by Debian (cups, gcc-6, irssi, kernel, and squid3), Fedora (mupdf), Mageia (irssi, mpv, qpdf, and quagga), openSUSE (libmad and postgresql95), SUSE (kernel and php5), and Ubuntu (kernel, linux-lts-trusty, linux-raspi2, and wavpack).

The BPF virtual machine is working its way into an increasing number ofkernel subsystems. The previous article inthis series introduced the BPF Compiler Collection (BCC), whichprovides a set of tools for working with BPF. But there is more to BCCthan a set of administrative tools; it also provides a developmentenvironment for those wanting to create their own BPF-based utilities.Read on for an exploration of that environment and how it can be used tocreate programs and attach them to tracepoints.

Security updates have been issued by Arch Linux (strongswan), Fedora (torbrowser-launcher), openSUSE (libdb-4_5, libdb-4_8, postgresql96, python3-openpyxl, and xv), Red Hat (rh-maven35-jackson-databind), and Ubuntu (kernel, libreoffice, linux, linux-aws, linux-kvm, linux-raspi2, linux-snapdragon, linux-hwe, linux-azure, linux-gcp, linux-oem, and linux-lts-xenial, linux-aws).

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

The XFS filesystem has been in the kernel for fifteen years and was used inproduction on IRIX systems for five years before that. But it might justbe time to teach that "old dog" of a filesystem some new tricks, DaveChinner said, at the beginning of his linux.conf.au 2018 presentation.There are a number of features that XFS lacks when compared to more modernfilesystems, such as snapshots and subvolumes; but he has been thinking—andwriting code—on a path to get them into XFS.

Terms like "cloud-native" and "web scale" are often usedand understood as pointless buzzwords. Under the layers of marketing, though,cloud systems do work best with a new and different way of thinking about systemadministration. Much of the tool set used for cloud operations is freesoftware, and Linux is the platform of choice for almost all cloud applications. While just about any distribution can be made to work, there areseveral projects working to create a ground-up system specifically for cloudhosts. One of the best known of these is Project Atomic from Red Hat and theFedora Project.

<p>Some days it seems that wherever two or more free-software enthusiastsgather together, there also shall be licensing discussions. One such,which can get quite heated, is the question of whether a givenfree-software license is a license, or whether it is really a contract. This distinction is important, because most legal systems treat the twodifferently. I know from personal experience that that discussion can goon, unresolved, for long periods, but it had not previously occurred tome to wonder whether this might be due to the answer being different indifferent jurisdictions. Fortunately, it has occurred to some lawyersto wonder just that, and three of them came together at FOSDEM 2018 topresent their conclusions.<p>Subscribers can read on for a report on the talk by guest author Tom Yates.

At this year's FOSDEM in Brussels,Jan Tobias Mühlberg gave a talk on thelatest work on Sancus, aproject that was originally presentedat the USENIX Security Symposium in 2013. The project is a fullyopen-source hardware platform to support "trustedcomputing" and other security functionality. It is designed to be used forinternet of things (IoT)devices, automotive applications, critical infrastructure, and otherembedded devices where trusted code is expected to be run.

Security updates have been issued by Arch Linux (libmspack), Debian (zziplib), Fedora (ca-certificates, firefox, freetype, golang, krb5, libreoffice, monit, patch, plasma-workspace, ruby, sox, tomcat, and zziplib), openSUSE (dovecot22, glibc, GraphicsMagick, libXcursor, mbedtls, p7zip, SDL_image, SDL2_image, sox, and transfig), Red Hat (chromium-browser), and Ubuntu (cups, libvirt, and qemu).

Anders Hovmöller has posted an account of migrating a large application to Python 3. There were multiple steps on the journey and plenty of lessons learned. "Our philosophy was always to go py2 -> py2/py3 -> py3 because we just could not realistically do a big bang in production, an intuition that was proven right in surprising ways. This meant that 2to3 was a non starter which I think is probably common. We tried a while to use 2to3 to detect Python 3 compatibility issues but quickly found that untenable too. Basically it suggests changes that will break your code in Python 2. No good.The conclusion was to use six, which is a library to make it easy to build a codebase that is valid in both in Python 2 and 3."

Security updates have been issued by Debian (libav), Gentoo (chromium, firefox, libreoffice, mysql, and ruby), SUSE (kernel), and Ubuntu (bind9).

The Linux kernel currently supports two separate network packet-filteringmechanisms: iptables and nftables. For the last few years, it has beengenerally assumed that nftables would eventually replace the older iptablesimplementation; few people expected that the kernel developers would,instead, add a third packet filter. But that would appear to be what ishappening with the newly announced bpfiltermechanism. Bpfilter may eventually replace both iptables and nftables, butthere are a lot of questions that will need to be answered first.

Security updates have been issued by Arch Linux (irssi), Debian (bind9, gcc-4.9, plasma-workspace, quagga, and tomcat-native), Fedora (p7zip), Mageia (nasm), openSUSE (exim, ffmpeg, irssi, mpv, qpdf, quagga, rrdtool, and rubygem-puppet), and SUSE (p7zip and xen).

SuiteCRM is a fork of the formerlyopen-source SugarCRM customer relationship management system.The 7.10 releasehas been announced. "SuiteCRM 7.10 includes a long list ofenhancements, improving user experience, adding new functionality andproviding a new REST API. This edition of SuiteCRM also assists companiesto be ready for GDPR, including opt-in functionality to track the consentof individuals."

The second 4.16 kernel prepatch is out."Go out and test, it all looks fine."

The4.15.4,4.14.20,4.9.82,4.4.116, and3.18.95stable kernel updates have all been released. These kernels contain arelatively large set of important fixes and updates.

Thefifth version of the patch series addingthe boot-constraint subsystem is under review on the linux-kernel mailing list. The purpose of this subsystem is tohonor the constraints put on devices by thebootloader before those devices arehanded over to the operating system (OS) — Linux in our case. If theseconstraints are violated, devices may fail to work properly once the kernelstarts reconfiguring the hardware; by tracking and enforcing thoseconstraints, instead, we can ensure that hardware continues to workproperly until the kernel is fully operational.

Security updates have been issued by Debian (quagga), Mageia (freetype2, kernel-linus, and kernel-tmb), openSUSE (chromium, GraphicsMagick, mupdf, openssl-steam, and xen), Slackware (irssi), SUSE (glibc and quagga), and Ubuntu (quagga).

For as long as the kernel has included tracepoints, developers have arguedover whether those tracepoints are part of the kernel's ABI. Tracepointchanges have had to be reverted in the past because they broke existinguser-space programs that had come to depend on them; meanwhile, fears ofsetting internal code in stone have made it difficult to add tracepoints toa number of kernel subsystems. Now, a new tracing functionality is beingproposed as a way to circumvent all of those problems.

Linux Journal takes a look at the newly announced LinuxBoot project. LWN covered a related talk back in November. "Modern firmware generally consists of two main parts: hardware initialization (early stages) and OS loading (late stages). These parts may be divided further depending on the implementation, but the overall flow is similar across boot firmware. The late stages have gained many capabilities over the years and often have an environment with drivers, utilities, a shell, a graphical menu (sometimes with 3D animations) and much more. Runtime components may remain resident and active after firmware exits. Firmware, which used to fit in an 8 KiB ROM, now contains an OS used to boot another OS and doesn't always stop running after the OS boots. LinuxBoot replaces the late stages with a Linux kernel and initramfs, which are used to load and execute the next stage, whatever it may be and wherever it may come from. The Linux kernel included in LinuxBoot is called the 'boot kernel' to distinguish it from the 'target kernel' that is to be booted and may be something other than Linux."

Security updates have been issued by Debian (jackson-databind, leptonlib, libvorbis, python-crypto, and xen), Fedora (apache-commons-email, ca-certificates, libreoffice, libxml2, mujs, p7zip, python-django, sox, and torbrowser-launcher), openSUSE (libreoffice), SUSE (libreoffice), and Ubuntu (advancecomp, erlang, and freetype).

The LWN.net Weekly Edition for February 15, 2018 is available.

A scientist with a rather unusual name, Meow-Ludo Meow-Meow, gave a talk atlinux.conf.au 2018about the current trends in "do it yourself" (DIY) biology or"biohacking". He is perhaps most famous for beingprosecuted for implanting an Opal card RFID chip into his hand; theOpal card is used for public transportation fares in Sydney. He gave moredetails about his implant as well as describing some other biohackingprojects in an engaging presentation.

Mark Wielaard writesabout the recently discovered relicensing of the dtrace dynamic tracingsubsystem under the GPL. "Thank you Oracle for making everyone’slife easier by waving your magic relicensing wand!Now there is lots of hard work to do to actually properly integrate this. And I am sure there are a lot of technical hurdles when trying to get this upstreamed into the mainline kernel. But that is just hard work. Which we can now start collaborating on in earnest."

The 2018 USENIXEnigma conference was held for the third time in January. Among many interesting talks, three presentations dealing with human securitybehaviors stood out. This article covers the key messages of these talks,namely the finding that humans are social in their securitybehaviors: their decision to adopt a good security practice is hardly everan isolated decision.Subscribers can read on for the report by guest author ChristianFolini.

Volker Lendecke is one of the first contributors to Samba,having submitted his first patches in 1994. In addition to developingother important file-sharing tools, he's heavily involved in development ofthe winbind service, which is implemented in winbindd. Although the core Active Directory (AD) domain controller(DC) code was written by his colleague Stefan Metzmacher, winbind is acrucial component of Samba's AD functionality. In his information-packed talk at FOSDEM2018, Lendecke said he aimed to give a high-level overview of what AD and Samba authentication is, and in particular thecommunication pathways and trust relationships between the parts ofSamba that authenticate a Samba user in an AD environment.

Security updates have been issued by Arch Linux (exim and mpv), Debian (advancecomp and graphicsmagick), Red Hat (collectd, erlang, httpd24-apr, openstack-aodh, and openstack-nova), SUSE (kernel and xen), and Ubuntu (libvorbis).

Much as some of us would love never to have to deal with Windows,it exists. It wants to authenticate its users and shareresources like files and printers over the network. Although manyenterprises use Microsoft tools to do this, there is a free alternative,in the form of Samba. While Samba 3 has been happily providingauthentication along with file and print sharing to Windows clients formany years, the Microsoft world has been slowly moving toward Active Directory (AD).Meanwhile, Samba 4, which adds a free reimplementation of AD on Linux, hasbeen increasingly ready for deployment. Three short talks at FOSDEM 2018provided three different views of Samba 4, also known as Samba-AD,and left behind a pretty clear picture that Samba 4 is trulyready for use.Subscribers can read on for a report from guest author Tom Yates on the first two of those talks; stay tuned for another on the third soon.

Stable kernels 4.15.3, 4.14.19, and 4.9.81 have been released. They all containimportant fixes and users should upgrade.

Security updates have been issued by Arch Linux (sthttpd), Debian (clamav, libreoffice, and pound), openSUSE (ipsec-tools and leptonica), SUSE (libreoffice), and Ubuntu (exim4, firefox, php5, puppet, and wavpack).

While there is a lot of software distributed under the terms of the GNUGeneral Public License, there is relatively little enforcement of the termsof that license and, it seems, even less discussion of enforcement ingeneral. Theorganizers of linux.conf.au have never shied away from such topics, though,so Karen Sandler's enforcement update during the linux.conf.au 2018 KernelMiniconf fit right in. The picture she painted includes a number of challenges forthe GPL and the communities based on it, but there are some bright spots aswell.

Norbert Preining reportsthe sad news that Staszek Wawrykiewicz has died. "Staszek was anactive member of the Polish TeX community, and an incredibly valuable TeXLive Team member. His insistence and perseverance have saved TeX Live frommany disasters and bugs. Although I have been in contact with Staszek overthe TeX Live mailing lists since some years, I met him in person for thefirst time on my first ever BachoTeX, the EuroBachoTeX 2007. Hisfriendliness, openness to all new things, his inquisitiveness, all took agreat place in my heart." (Thanks to Paul Wise)

At the close of the 4.16 merge window,11,746non-merge changesets had been merged; that is 5,000 since last week's summary. This merge window isthus a busy one, though not out of line with its predecessors — 4.14 had11,500 changesets during its merge window, while 4.15 had 12,599. Quite abit of that work is of the boring internal variety; over 600 of thosechangesets weredevice-tree updates, for example. But there was still a fair amount ofinteresting work merged in the second half of the 4.16 merge window; readon for the highlights.

Security updates have been issued by Arch Linux (go, go-pie, and plasma-workspace), Debian (audacity, exim4, libreoffice, librsvg, ruby-omniauth, tomcat-native, and uwsgi), Fedora (tomcat-native), Gentoo (virtualbox), Mageia (kernel), openSUSE (freetype2, ghostscript, jhead, and libxml2), and SUSE (freetype2 and kernel).

Jim Gettys providesan extensive look at the FQ_CoDel queue-management algorithm as a bigpiece of the solution to bufferbloat problems. "Simple'request/response' or time based protocols are preferentially scheduledrelative to bulk data transport. This means that your VOIP packets, yourTCP handshakes, cryptographic associations, your button press in your game,your DHCP or other basic network protocols all get preferential servicewithout the complexity of extensive packet classification, even under veryheavy load of other ongoing flows. Your phone call can work well despitelarge downloads or video use."

Linus has released 4.16-rc1 and closed themerge window for this development cycle. "I don't want to jinxanything, but things certainly look a lot better than with 4.15. We have no(known) nasty surprises pending, and there were no huge issues during themerge window. Fingers crossed that this stays fairly calm and sane."

Linux networking maintainer David Miller has put out a call for proposals for a two-day networking track at this year's Linux Plumbers Conference (LPC). "We are seeking talks of 40 minutes in length, accompanied by papersof 2 to 10 pages in length." The deadline for proposals is July 11. LPC will be held November 13-15 in Vancouver and the networking track will be held the first two days.

In ACMQueue magazine, Bridget Kromhout writes about containers and why they are not the solution to every problem. The article is subtitled:"Complex socio-technical systems are hard;film at 11.""Don't get me wrong—containers are delightful! But let's be real: we're unlikely to solve the vast majority of problems in a given organization via the judicious application of kernel features. If you have contention between your ops team and your dev team(s)—and maybe they're all facing off with some ill-considered DevOps silo inexplicably stuck between them—then cgroups and namespaces won't have a prayer of solving that.Development teams love the idea of shipping their dependencies bundled with their apps, imagining limitless portability. Someone in security is weeping for the unpatched CVEs, but feature velocity is so desirable that security's pleas go unheard. Platform operators are happy (well, less surly) knowing they can upgrade the underlying infrastructure without affecting the dependencies for any applications, until they realize the heavyweight app containers shipping a full operating system aren't being maintained at all."

On his blog, Tom Tromey looks at just-in-time (JIT) compilation for Emacs and what he has done differently in his implementation from what was done in earlier efforts. He also looks at potential enhancements to his JIT: "Calling a function in Emacs Lisp is quite expensive. A call from the JIT requires marshalling the arguments into an array, then calling Ffuncall; which then might dispatch to a C function (a “subr”), the bytecode interpreter, or the ordinary interpreter. In some cases this may require allocation.This overhead applies to nearly every call — but the C implementation of Emacs is free to call various primitive functions directly, without using Ffuncall to indirect through some Lisp symbol.Now, these direct calls aren’t without a cost: they prevent the modification of some functions from Lisp. Sometimes this is a pain (it might be handy to hack on load from Lisp), but in many cases it is unimportant.So, one idea for the JIT is to keep a list of such functions and then emit direct calls rather than indirect ones."

Security updates have been issued by Arch Linux (clamav), Debian (mailman, mpv, and simplesamlphp), Fedora (tomcat-native), openSUSE (docker, docker-runc, containerd,, kernel, mupdf, and python-mistune), Red Hat (kernel), and Ubuntu (mailman and postgresql-9.3, postgresql-9.5, postgresql-9.6).

This is the third article of a series discussing various methods ofreducing the size of the Linux kernel to make it suitable for smallenvironments. The first articleprovided a short rationale for this topic, and covered link-timegarbage collection. Thesecond article covered link-timeoptimization (LTO) and compared its results to link-time garbagecollection. In this article we'll explore ways to make LTO moreeffective at optimizing kernel code away, as well as more assertivestrategies to achieve our goal.

Security updates have been issued by Debian (django-anymail, libtasn1-6, and postgresql-9.1), Fedora (w3m), Mageia (389-ds-base, gcc, libtasn1, and p7zip), openSUSE (flatpak, ImageMagick, libjpeg-turbo, libsndfile, mariadb, plasma5-workspace, pound, and spice-vdagent), Oracle (kernel), Red Hat (flash-plugin), SUSE (docker, docker-runc, containerd, golang-github-docker-libnetwork and kernel), and Ubuntu (libvirt, miniupnpc, and QEMU).

The LWN.net Weekly Edition for February 8, 2018 is available.

The Electronic Frontier Foundation mournsthe loss of John Perry Barlow, one of its founders. "It is noexaggeration to say that major parts of the Internet we all know and lovetoday exist and thrive because of Barlow’s vision and leadership. He alwayssaw the Internet as a fundamental place of freedom, where voices longsilenced can find an audience and people can connect with others regardlessof physical distance."

The4.15.2,4.14.18, and3.18.94stable kernels have been released; each contains the usual set of importantfixes and updates. There are no 4.9.x or 4.4.x updates coming in thisparticular set.

Eric Brown takesa look at the SiFive "HiFive Unleashed" SBC that runs Linux on itsRISC-V based, quad-core, 1.5GHz U540 SoC. "The open spec HiFive Unleashed board integrates a U540 SoC, 8GB of DDR4 RAM, and 32MB quad SPI flash. The only other major features include a microSD slot, a Gigabit Ethernet port, and an FMC connector for future expansion. A SiFive rep confirmed to Linux.com that the board will be open source hardware, with freely available schematics and layout files."

Karen Sandler has been giving conference talks about free software and openmedical devices for the better part of a decade at this point. LWN briefly covered a 2010 LinuxCon talk and a 2012 linux.conf.au (LCA) talk; her talk atLCA 2012 was her first full-length keynote, she said. In this year'sedition, she reviewed her history (including her love for LCA based in part on that 2012visit) and gave an update on the status of the source code for the device shehas implanted on her heart.

Security updates have been issued by Debian (mpv), Fedora (jackson-databind), Mageia (flash-player-plugin), Slackware (kernel), and Ubuntu (python-django).

Version5.0.0 of the KMyMoney personal finance manager is out. "Thelargest amount of work has gone towards basing this version on KDEFrameworks. Many of the underlying libraries used by the application havebeen reorganized and improved, but most of that is behind the scenes, andnot directly visible to the end user. Some of the general look and feel mayhave changed, but the basic functionality of the program remains the same,aside from intentional improvements and additions." Enhancementsinclude improved reports and better multiple-currency support.