LWN.net Weekly Edition for December 20, 2012

LWN's 2012 retrospective

Your editor was strongly tempted to skip out on the task of writing the 2012 year-end retrospective article. After all, the process of going through January's predictions and seeing how wrong they were is somewhat painful and embarrassing. Even worse, according to reliable sources, the world is scheduled to end just after this article is to be published, so it hardly seems worth the effort. But a quick consideration of how your editor's investment portfolio has performed under the guidance of similarly reliable sources suggests that covering all the bases might be prudent; it seems that some other peoples' predictions are even worse than those found here.

So, with a heavy heart, the process of reviewing last January's predictions began. And, in fact, the news wasn't all bad. The mobile patent wars did, indeed, get worse, to the point that it has gotten difficult to market certain devices in certain parts of the world. The fight for a free Internet continues, and SOPA was turned back as predicted. Red Hat did indeed have a good year. A number of the other, relatively obvious predictions also came through reasonably well. There is value, it seems, in not going too far out on a limb.

Another prediction read that we would see more focused competition between distributors, with each seeking to differentiate more from the others. To an extent that has certainly happened; witness all the work that has gone into making Ubuntu different from the rest. Other times, though, differences have not been seen as a selling point; Oracle's attempt to woo CentOS users is a case in point. So this prediction was, at best, only partially right. In the end, we are still far from having an understanding of what makes a perfect Linux distribution, even when judged through the narrow lens of commercial success.

At the beginning of the year, it appeared that the Linux Mint project had taken on too many projects; given that it had several versions of its distribution to support, along with two desktop forks, your editor reasoned that a "reckoning with reality" was in the works. At the end of the year, one might conclude that progress has slowed in some areas, especially with the MATE desktop. But, if a "reckoning with reality" has occurred, it must be concluded that reality does not drive a particularly hard bargain. The Linux Mint project appears to be vital and healthy.

Similarly, one might well conclude that the LibreOffice project is broader-based and stronger than Apache OpenOffice, but the former has not eclipsed the latter as predicted. The Apache project has managed to get its organizational issues worked out and graduate from the Apache incubator; clearly, it has more staying power than many of us might have thought.

Perhaps the worst, most wishful-thinking-tinged prediction, though, was the one that "the GNOME 3 wars will be long forgotten by the end of the year." One need only have a look at the comment stream that appears on any GNOME-related news to see that the wounds are still open and fresh. Someday the community will accept GNOME as it is, but that did not come to pass in 2012. Learning from experience, your editor is unlikely to predict a calming of the waters around GNOME 3 (or systemd) in 2013.

So it appears that this year's predictions were, as usual, a mixed bag. A true evaluation of a set of predictions is not complete, though, without looking at what was not predicted. As is often the case, your editor missed a few things that, in retrospect, should have been on the list.

For example, the regime change in the GNU libc project was well underway when the 2012 predictions were written. A more attentive eye would have called attention to the increasingly consensus-oriented way in which that project was being run. Making this project more contributor-friendly without a fork was a major achievement for everybody involved; one can only hope that this type of change will be repeated in other projects where it is necessary.

Mandriva's decision to hand control of its distribution to the community also makes sense in retrospect. Letting go of a project and hoping for community help is, after all, often the response of a company with intractable financial problems, especially if the company is somewhat community-oriented to begin with. It has been clear for a while that Mandriva SA has not been able to pull together the resources to develop its distribution properly; hoping that the community can do better is an obvious response to that situation.

Two items that would have been easy to predict in general — but difficult in the specifics — were the leap-second bug and the backdooring of Piwik. It is well understood that infrequently tested code will develop bugs over time; the leap second code had not been invoked in the real world since 2008. One could argue that somebody should have checked the code for cobwebs as the 2012 leap second approached, but nobody foresaw the problem. Meanwhile, it has been a while since the addition of backdoors to software distributions seemed to be a regular occurrence. But free software projects, especially those producing net-facing software like Piwik, will remain an attractive target for those who would like easy ways into otherwise well-secured systems. We will see this kind of thing happening again.

Finally, sometimes the most difficult-to-predict events can do the most to strengthen one's faith in humanity. An interesting trial in Oracle's software patent suit against Google was easy to foresee. But who would have imagined that the judge would learn Java and implement some of the claimed techniques on his own? We are far from fixing the patent system in the US (or anywhere else, for that matter), but there are signs that influential people are starting to figure out that there is a problem.

Of course, some things are just too routine to predict. Once upon a time, a community that could release six major kernels and an uncountable number of major releases of higher-level software in one year would have been seen as a hopeless fantasy. Now such things go almost unnoticed. Our community is strong, and free software continues relentlessly toward world domination. As a whole, it has been another good year.

We at LWN would like to thank our readers who have supported us through yet another year; it is worth noting that LWN will celebrate its 15th anniversary in January. We never predicted that we would be doing this for so long; it has been a good ride and we are far from done. Thanks to all of you who make it possible for us to continue to write from the heart of the Linux development community. On a personal note, your editor would like to especially thank all of you who offered your support through an exceptionally difficult year; you made a difference and it is much appreciated.

Comments (16 posted)

GnuTLS, copyright assignment, and GNU project governance

Copyright assignment is a topic that brings out strong passions in the free software community, especially when the assignee is a corporate entity. Assignment to a nonprofit entity such as the Free Software Foundation (FSF) may eliminate some of the problems that can occur when assigning copyright to a company. However, recent events in the GnuTLS project are a reminder that copyright assignment can have a number of downsides even when assigning to a nonprofit chartered with the goal of protecting free software.

The problem with (corporate) copyright assignment

Copyright assignment tends to evoke polarized opinions in the free software community. On the one hand, various companies have promoted copyright assignment agreements as being in the best interests of free software—Canonical is perhaps the most prominent example in recent times. On the other hand, the community at large seems more skeptical of the value of these agreements; Michael Meeks is among those who put the counterarguments well. Project Harmony, an attempt to create a standardized set of copyright licensing agreements, has met with a chilly reception from various quarters of the community, and (so far) seems to have gained little traction in the free software world.

A blog post by Richard Stallman on the FSF web site highlights the most significant of the risks of assigning copyright when contributing code to a commercially owned free software project. One of the powers conferred by a copyright assignment agreement is control of the choice of license of the software: as the copyright owner, the assignee (alone) has the power to change the license of the project. Commonly, corporate copyright assignment agreements place no restriction on the choice of license that the assignee may in the future choose, thus putting a great deal of power in the hands of the assignee. As Richard notes:

On the other hand, the Free Software Foundation requires copyright assignment for many of the projects hosted under the GNU umbrella. This is a choice of the project creators when making the project a GNU project. The main reason given for this is that being the sole copyright holder puts the FSF in the best position to enforce copyright in the event of a GPL violation. Of course, being the sole copyright owner also gives the FSF the ability to change the license on a GNU project. However, the motivations of a company and the FSF differ substantially: whereas a company is ultimately motivated by profit (and its motivations can change with shifting financial circumstances and changes of company ownership), the FSF is a non-profit charity chartered to further the interests of free software. Thus, its copyright assignment agreement includes an explicit promise that any future distribution of the work will be under some form of free software license.

GnuTLS and the FSF

GnuTLS is "a secure communications library implementing the SSL, TLS and DTLS protocols". The project was founded in 2000, under the GNU umbrella, by Nikos Mavrogiannopoulos. Over the life of the project, the other major contributor has been Simon Josefsson.

That there was a problem in the project became unmistakable on December 10, when Nikos posted the following note (entitled "gnutls is moving") to the gnutls-devel mailing list:

This elicited a rather blunt response (entitled "GNUTLS is not going anywhere") from Richard Stallman:

Richard's response raises a number of interesting issues. The matter of ownership of the project name is perhaps the simplest, and was acknowledged by Nikos:

In the days since then, however, the name hasn't changed and there does not seem to have been a formal (public) request to do so. One possible reason for this might be found in a response to Richard's mail from Werner Koch (maintainer and primary author of GnuPG and libgcrypt, both of which are GNU projects):

Indeed, of the somewhat more than 11,000 commits in the GnuTLS Git repository, all but around 400 are by either Nikos or Simon. Simon has not spoken up in the current mail thread, but he remains an active contributor to the project.

Thus, while the FSF might have some legal claim on the project name based on common law trademarks, such a claim is, morally speaking, less clear. Furthermore, there are existing projects, such as gnuplot and Gnutella that riff on the "GNU" name without being official GNU projects; indeed, Gnutella does this despite an FSF request that the name should be changed. Also noteworthy in this context is the fact that the gnutls.org domain is registered to Nikos.

Having worked within the framework of the GNU project for 12 years, Nikos's reasons for wanting to move out of the project must have been important ones. In response to a question from Eli Zaretskii about his reasons, Nikos said:

Nikos then went on to outline three criticisms of the FSF and GNU projects. The first of these related to copyright assignment:

As Richard confirmed, assignment of copyrights for all GNU projects (that employ assignment) is solely to the US-based FSF, rather to one of the regional sister organizations (located in Europe, India, and South America). One can easily imagine a number of reasons for this state of affairs. Given the FSF's desire to have a single copyright holder, it makes sense to assign all copyrights in an individual GNU project to a single entity, and for administrative and legal reasons it is probably simpler to assign copyrights for all projects to the same entity.

However, one can also imagine that when the primary developers of a project reside outside the US—both Nikos and Simon are in Europe—the requirement to assign to the US-based FSF, rather than FSF Europe, is irksome. In addition, the FSF Europe tends to have a quieter, less confrontational style of working than its US counterpart, which may also have been a factor in Nikos desire to assign copyright to the European organization.

The other theme that came out in Nikos's criticisms was the problem of feeling figuratively distanced from the parent project:

The lack of openness was a theme echoed by Werner in reply to Eli's question:

The content of the discussion that Werner refers to is, of course, unavailable, so it is difficult to gain further insight into why discussions on the gnu-prog-discuss mailing list need to be secret.

Clearly, at least a few GNU project maintainers are quite unhappy with the current governance of the umbrella project. And when a maintainer of twelve years' standing wants out of the GNU project, that suggests that there are some serious governance problems.

Of course, this is hardly the first time that governance issues have caused significant division in GNU projects. The GCC project is one of the most notable cases, providing an example both in the late 1990s, with the egcs fork of the GCC compiler (where the fork ultimately supplanted the original GCC project inside the GNU project), and more recently when questions on plugin licensing led the FSF to pressure the GCC project to delay the GCC 4.4 release, to the disgruntlement of many GCC hackers.

The problems of assigning copyright to a nonprofit

The events in the GnuTLS project reveal a number of the problems of copyright assignment that remain even when assigning to a nonprofit such as the FSF.

The first of these problems has already been shown above: who owns the project? The GnuTLS project was initiated in good faith by Nikos as a GNU project. Over the lifetime of the project, the vast majority of the code contributed to the project has been written by two individuals, both of whom (presumably) now want to leave the GNU project. If the project had been independently developed, then clearly Nikos and Simon would be considered to own the project code and name. However, in assigning copyright to the FSF, they have given up the rights of owners.

The mailing list thread also revealed another loss that developers suffer when signing a copyright assignment agreement. As noted above, the ability of the FSF—as the sole copyright holder—to sue license violators is touted as one of the major advantages of copyright assignment. However, what if, for one reason or another, the FSF chooses not to exercise its rights? Juho Vähä-Herttua raised this point in the mail thread:

The blog post that Juho refers to questions a number assumptions around FSF copyright assignment. In the post, Werner states:

Once a developer assigns copyright, they are at the mercy of the assignee to enforce the copyright. In this particular case, one can speculate that the failure to pursue the violation was likely a shortage of human resources. As Richard noted, "We have staff for GPL enforcement, […] but there are so many violations that they can't take action on all."

But that very response throws into question the wisdom of assigning a large number of copyrights to a resource-starved central organization. A more distributed approach to dealing with copyright violations would seem more sensible. And indeed, organizations such as gpl-violations.org and the Software Freedom Conservancy have shown that the GPL violations can be successfully fought without being the sole copyright holder in a work of code. By now, the argument that copyright assignment is necessary to successfully enforce free software licenses is rather weak.

Werner outlines a few other problems with FSF copyright assignment. One of these is the seemingly arbitrary nature of copyright assignment across GNU projects. He points out that there are two cryptographic libraries that are part of the GNU project, one of which (libgcrypt) requires copyright assignment while the other (Nettle) does not. The seeming arbitrariness in this example was further emphasized by the fact that GnuTLS (which, as we already saw, requires copyright assignment) switched from using libgcrypt to using Nettle.

The rationale that copyright assignment is necessary to allow relicensing also strikes Werner as dubious. He considers the two likely scenarios for relicensing GPLed software. One of these is relicensing to a later version of the GPL. This scenario is in most cases already covered by the default "or later" language that is usually applied to software licensed under the GPL. Although there are projects that deliberately exclude the "or later" clause when applying the GPL—most notably the Linux kernel—it's likely that few or no GNU projects exclude that clause. Projects that exclude the "or later" language of the GPL are likely also to avoid using copyright assignment.

The other likely scenario for relicensing a GPL project is to relax the license constraints—for example, switching from GPL to LGPL, so as to allow interoperability with software that is not under a GPL-compatible license. Such relicensing can be performed even when the project lacks a copyright assignment (as was recently done for portions of the VLC code base). However, this requires a formidable effort to obtain permissions from all contributors. But, Werner points out, the FSF has in practice rarely been interested in relaxing licensing constraints in this way.

In summary, using copyright assignment as a tool to allow relicensing seems to serve little practical use for the FSF, and comes at the cost of removing the contributor's freedom to relicense their code.

Werner's blog post highlighted one more problem with copyright assignment—a problem that occurs with assignment both to companies and to nonprofits. The requirement to sign a copyright assignment agreement imposes a barrier on participation. Some individuals and companies simply won't bother with doing the paperwork. Others may have no problem contributing code under a free software license, but they (or their lawyers) balk at giving away all rights in the code. In general, those contributors just silently fail to appear. By chance, a discussion on copyright assignment is currently taking place in the Gentoo project, where Greg Kroah-Hartman, a long-standing contributor to the project, commented on this point:

To illustrate his point, Werner related his recent experience with the libgcrypt project. Concluding that copyright assignment served little practical use, he relaxed that requirement for libgcrypt: starting in April of this year, he permitted contributions accompanied by an emailed kernel-style developer certificate of origin. The result was a noticeable increase in patches sent in to the project.

Concluding remarks

The risks of assigning copyright to corporate entities have in the past been well publicized. Assigning copyright to a nonprofit eliminates the most egregious of those risks, but carries its own burdens and risks, which have not necessarily been so well publicized. One of those burdens is the necessity of buying into an associated governance model, one that may or may not work well for project developers. The FSF governance model is, it seems, not working well for a number of GNU projects. Developers should consider (in advance) the questions of project ownership that are bound to arise if the governance model does not work for them and they want to separate from the governing project.

In addition, the costs of assigning copyright to a nonprofit should be balanced against the (supposed) benefits. The assertion that assigning copyright to a single entity improves the chances of successful prosecution of a copyright violations looks dubious when one considers that the assignee may not be well enough resourced to prosecute every violation. To that should be added the facts that assignment means that the assigner loses the ability to themselves prosecute copyright violations and that copyright violations have been successfully prosecuted even when there is no single copyright holder. Finally, the value of copyright assignment as a tool that permits the FSF to relicense code seems rather limited in practice. In summary, the arguments for copyright assignment start to look decidedly weak, even when the assignee is a nonprofit such as the FSF, and it is hard to find any justification for the FSF maintaining this requirement.

(Thanks to Carlos Alberto Lopez Perez for the heads-up.)

Comments (83 posted)

2012 Linux and free software timeline - Q4

Here is LWN's fifteenth annual timeline of significant events in the Linux and free software world. We have broken the timeline up into quarters, and this is our report on October-December 2012 (updated on December 31). Eventually, the quarterly timelines will be stitched together to create a timeline for the year as a whole, but in the meantime, you can find the other quarterly articles here:

• January-March 2012
• April-June 2012
• July-September 2012

---

This is version 0.8 of the 2012 timeline. There are almost certainly some errors or omissions; if you find any, please send them to timeline@lwn.net.

LWN subscribers have paid for the development of this timeline, along with previous timelines and the weekly editions. If you like what you see here, or elsewhere on the site, please consider subscribing to LWN.

If you'd like to look further back in time, our timeline index page has links to the previous timelines and some other retrospective articles going all the way back to 1998.

October

Samsung releases the F2FS filesystem (blurb and article).

KDE releases a manifesto (LWN blurb).

HTTPS Everywhere 3.0 is released (announcement).

Systemtap 2.0 is released (announcement).

The first Korea Linux Forum is held in Seoul, October 11-12 (LWN report).

Canonical provides users with a mechanism to directly fund development of Ubuntu (LWN article).

NetBSD 6.0 is released (announcement).

The Whonix distribution makes an alpha release (LWN article).

The Privacyfix browser plugin is released (LWN article).

Plasma Active Three is released (LWN blurb).

The 2012 Realtime Minisummit is held in Chapel Hill, North Carolina, in conjunction with the 14th Real Time Linux Workshop, October 18-20 (LWN minisummit coverage; LWN coverage of workshop sessions: Modeling systems with Alloy; Realtime Linux for aircraft).

An ext4 data corruption bug receives wide media coverage, but in practice is rather difficult to trigger (LWN blurb and article).

The Debian technical committee renders a judgement regarding long-standing difficulties between the maintainers of various Debian Python packages (LWN article).

Ubuntu 12.10 (Quantal Quetzal) is released (announcement).

Apache OpenOffice graduates from the Apache Incubator (announcement).

Git 1.8.0 is released (announcement).

Wayland and Weston 1.0 are released (announcement).

Arduino 1.5 is released (announcement).

Yocto 1.3 "danny" is released (announcement).

November

The Linaro Enterprise group is formed (announcement).

The openSUSE project releases openSUSE 12.2 for ARM (announcement).

The Fedora project announces an alpha release of Fedora 18 that supports ARM; the Fedora ARM developers hope to make F18 the first release that supports ARM as a primary architecture. (announcement).

OpenBSD 5.2 is released (LWN blurb and article on some challenges that OpenBSD the other BSDs face in trying to keep pace with Linux).

Asterisk 11 is released (LWN blurb).

The release date of Fedora 18 slips significantly, from the originally expected November to January (announcement, LWN article).

LinuxCon Europe is held in Barcelona, Spain, November 5-9 (LWN coverage: Challenges for Linux networking; Systemd two years on; The failure of operating systems and how we can fix it; All watched over by machines of loving grace; Realtime, present and future; Checkpoint/restore in user space: are we there yet?; Don't play dice with random numbers).

The GNOME project announces that fallback mode will be dropped in the upcoming 3.8 release (LWN blurb; a short time later, the project announces plans for a "classic" mode).

Android 4.2 is released (LWN article).

The VLC projects completes relicensing much of its code from GPL to LGPL (LWN article).

The Portuguese government adopts ODF (LWN blurb).

A backdoor is inserted into the Piwik web server; the problem is quickly fixed and notified (LWN blurb).

Linux Mint 14 is released (announcement).

Upstart 1.6 is released (LWN blurb).

The CyanogenMod project starts releasing stable builds of CyanogenMod 10 (LWN article on running this version on the Nexus 7 tablet).

Wikipedia rolls out an HTML5 video player (LWN article).

Ubuntu makes a distribution for the Nexus 7 (LWN article).

Darktable 1.1 is released (LWN article).

December

The Google Summer of Code Doc Camp 2012 takes place in Mountain View, California, December 3-7 (LWN coverage: Documentation unconference; Book sprints).

NetBSD 5.2 is released (announcement).

The MariaDB Foundation is formed (announcement).

Ekiga 4.0 is released (announcement, LWN article).

The first "shim" UEFI secure bootloader is released (announcement).

Linux 3.7 is released (announcement; KernelNewbies summary; LWN merge window summaries: part 1, part 2, and part 3; LWN development statistics article).

Firefox OS Simulator 1.0 is released (LWN article).

SparkleShare 1.0 is released (LWN blurb).

Bison 2.7 is released (announcement).

Richard Stallman criticizes desktop searching in Ubuntu Unity, which relays search terms to Canonical servers (LWN blurb and article).

Samba 4.0 is released (announcement and earlier article).

A number of Samsung Android phones are revealed to have a significant security hole, a device file that gives write access to all physical memory on the phone (LWN blurb).

Eudev, a project to create a Gentoo-based fork of udev, is launched (announcement, LWN article).

Qt 5.0 is released (LWN blurb).

PulseAudio 3.0 is released (announcement).

The status.net service is phased out, and replaced by pump.io (LWN blurb).

Gnumeric 1.12 released (announcement).

The Perl programming language turns 25 this month (timeline from Perl Foundation News).

A hash-based DoS attack on Btrfs is disclosed (LWN blurb).

LLVM 3.2 is released (announcement, release notes).

Discontent in the GNU project becomes evident as the GnuTLS maintainer moves the project outside GNU and the GNU sed maintainer resigns (sed maintainer resignation note, LWN article on events in the GnuTLS project).

Awesome 3.5 is released (LWN blurb and earlier article on this window manager).

Enlightenment 0.17 is released (announcement and earlier LWN article on this window manager).

The GNU C library (glibc) version 2.17 is released (announcement).

FreeBSD 9.1 is released (announcement, release notes).

BlueZ 5.0 is released (announcement, LWN article).

GNU Automake 1.13 is released (announcement).

Comments (none posted)

Happy holidays from LWN

This is the last LWN Weekly Edition for 2012; following our longstanding tradition, we will be taking a break during the last week of the year to rest, be with our families, and recover from too much good food and wine. We wish the best holidays to all of our readers, and a happy new year as well. The Weekly Edition will return on January 4.

Comments (2 posted)

Page editor: Jonathan Corbet

Security

Fedora and secure release upgrades

As Fedora 18 nears its final release, some project members are concerned that churn in the update tools has placed users in a risky position by eliminating secure paths to update an existing installation from Fedora 17. Although it looks like workarounds will be available, the resulting choice will pit convenience against security, which is rarely a trade-off that ends up in security's favor. But as the whole debate nicely illustrates, when it comes to verifying the authenticity of software acquired over the network, no matter how many steps are involved, eventually the chain of trust must start somewhere — because users always make a leap of trust when first clicking on the download option.

The root of the issue is FedUp, the brand-new updater currently being developed for deployment with F18, which does not check the cryptographic signatures of the RPM packages it downloads over the network (although FedUp also downloads initramfs and vmlinuz files at the start of an upgrade; it does verify the integrity of these by checking their SHA256 checksums). A bug highlighting that deficiency was filed in November, noting that fetching and installing unverified binaries over the network leaves the system vulnerable to man-in-the-middle attacks and to trojaned packages on compromised mirrors. Fedora's RPM packages are signed, and various package installer tools do verify the signatures; it is only the FedUp release-upgrading tool that does not check the signatures before installing them.

The Fedora Engineering Steering Committee (FESCo) discussed the subject in its December 5 meeting and decided that the absence of network verification would not block the release of F18. Rahul Sundaram raised the importance of the issue on the fedora-devel list a week and a half later, arguing that the lack of a secure method to update from F17 to F18 was irresponsible. Part of Sundaram's initial concern was that the still-unfinished FedUp did not yet support updating from an optical disc, which would provide some measure of protection against attack because Fedora's downloadable ISO images are provided with checksums. That concern turned out to be partly unfounded; as Red Hat's Tim Flink explained in a different thread, FedUp does support extracting packages from optical media — it just does not support booting from an optical disc to upgrade an existing installation, or pulling packages from an ISO file.

Upgrades and release blockers

But the optical disc upgrade option is not the default behavior for FedUp; the user must know to employ it with the --device switch. FedUp's default is still to fetch packages from a remote repository. At the moment, FedUp is also fetching these pre-release packages over an unencrypted HTTP connection, although that could change when the final F18 is released. One can always argue that users in the know will seek out the secure means to update their machines, but it is far less risky to make the default behavior secure. After all, "users in the know" are not the ones most in need of protection. On that point, Sundaram noted in his original email that FedUp's lack of package verification is not a regression, since the update tool that it replaces, PreUpgrade, did not check package signatures either. Neither does Anaconda, the Fedora installer.

The only release-upgrade path that ever has verified remote repository package signatures was that of upgrading via the yum package manager, which is an unsupported option that non-advanced users are steered away from — and with good reason. Yum is a lower-level package installation utility; it can be used to manually upgrade the entire system to a new release, but the procedure is not recommended because a release upgrade involves more than simple package installation. Dedicated upgrade tools like PreUpgrade and FedUp are designed to handle large or complicated system changes between releases, such as the merging of /bin and other directories into the /usr hierarchy. Some of these changes require a reboot, which PreUpgrade and FedUp are built to manage, but yum is not.

Sundaram opened a FESCo ticket asking FESCo to classify the FedUp signature-verification issue as a blocker — although he later closed it after determining that the local-media option does offer a secure upgrade path for those that seek it out. But the issue is also tangled up with the question of whether or not FedUp is ready for release on other grounds. It still lacks a GUI front-end, logging, and progress indication. The GUI in particular is a limitation that some see as critical in its own right (Sundaram called it "a severe regression").

The fedora of trust

FESCo decided to defer the FedUp GUI feature until F19, and the question of providing any secure way to upgrade an F17 machine to F18 appears, for the moment, to be settled. The deeper question of making such a secure upgrade the default, however, remains unanswered.

Fedora's distribution upgrade tools have never baked signature verification into the upgrade process, and the project knows it. The discussion dates all the way back to the infamous bug 998, first opened in 1999 and filled with mysterious references to forgotten technologies like floppy disks (hint for younger readers: imagine a really thin SSD). But securely checking package signatures requires a secure method for the user to acquire the right public key (with which to check said signatures) in the first place. Even yum, which was raised during the FedUp discussion as the secure upgrade option, needs the user to manually find and import the correct GPG key for the new release. That is a weak link even in the manual case, as Fedora QA team member Adam Williamson observed:

Finding a way for the Fedora N release upgrade tool to securely fetch and install the correct key for release N+1 automatically is a tricky problem indeed. For example, Will Woods proposed a plan to add GPG signatures for the initramfs and vmlinuz files FedUp fetches at the beginning of the upgrade. As mentioned above, currently only a SHA256 checksum is used to verify the integrity of these files — courtesy of checksums found in the repository's .treeinfo file. Woods proposed adding GPG signatures to the repository at .treeinfo.signed, but noted that there still needs to be a way to get the F18 key onto F17 systems, and some way for the user to decide if the F18 key is trustworthy.

Establishing a chain of trust can be a bit of a chicken-and-egg problem: eventually one has to place one's trust in something on which the subsequent links build. Till Maas suggested to Woods that the F18 key could be securely fetched from the Fedora project from a well-known location over HTTPS. Of course, that relies on the security of HTTPS and the DNS system, which relies on the security of the certificate authorities, and so on.

For most mortals, however, some security — however limited — is still better than no security, which is what FedUp's default usage provides now. As recently as the end of November, users were still writing to the list confused about how best to upgrade their machines. There are clearly many more discussions ahead; even if Fedora establishes a workable plan for its main releases, also problematic is how downstream distributions (including Fedora "spins") and customized ISOs are handled. Whatever solution develops, one thing is for certain: it will not arrive until the F19 release cycle at the earliest.

Comments (11 posted)

Brief items

Security quotes of the week

-- Matt Mackall

-- Roger Dingledine

-- Mike Masnick

-- Lauren Weinstein

Comments (1 posted)

A hash-based DoS attack on Btrfs

Pascal Junod has disclosed a pair of denial-of-service attacks against the Btrfs filesystem based on hash collisions. "I have created several files with random names in a directory (around 500). The time required to remove them is negligible. Then, I have created the same number of files, but giving them only 55 different crc32c values. The time required to remove them is so large that I was not able to figure it out and killed the process after 220 minutes (!)." This is a local attack only, but administrators of Btrfs-using sites with untrusted users may want to pay attention.

Comments (41 posted)

World-writable memory on Samsung Android phones

Here's a report on the xda-developers site stating that Samsung Android phones have an interesting feature added to the kernel: a /dev/exynos-mem device, world-writable, that gives access to all physical memory on the handset. "The good news is we can easily obtain root on these devices and the bad is there is no control over it." Owners of such phones might want to be especially careful about which software they install for a little while.

Comments (86 posted)

Suricata 1.4 released

Version 1.4 of the Suricata intrusion detection/prevention system is available. "The biggest new features of this release are the Unix Socket support, IP Reputation support and the addition of the Luajit keyword. Each of these new features are still in active development, and should be approached with some care." There's a lot of other new features and a number of performance improvements as well.

Full Story (comments: 2)

New vulnerabilities

apport: AppArmor policy is too lenient

Package(s):	apport	CVE #(s):
Created:	December 18, 2012	Updated:	December 19, 2012
Description:	From the Ubuntu advisory: Dan Rosenberg discovered that an application running under an AppArmor profile that allowed unconfined execution of apport-bug could escape confinement by calling apport-bug with a crafted environment. While not a vulnerability in apport itself, this update mitigates the issue by sanitizing certain variables in the apport-bug shell script.
Alerts:	Ubuntu USN-1668-1 2012-12-17

Comments (none posted)

apt: information disclosure

Package(s):	apt	CVE #(s):	CVE-2012-0961
Created:	December 19, 2012	Updated:	December 19, 2012
Description:	From the Ubuntu advisory: It was discovered that APT set inappropriate permissions on the term.log file. A local attacker could use this flaw to possibly obtain sensitive information.
Alerts:	Ubuntu USN-1662-1 2012-12-12

Comments (none posted)

aptdaemon: man-in-the-middle attack

Package(s):	aptdaemon	CVE #(s):	CVE-2012-0962
Created:	December 17, 2012	Updated:	December 19, 2012
Description:	From the Ubuntu advisory: It was discovered that Aptdaemon incorrectly validated PPA GPG keys when importing from a keyserver. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to install altered package repository GPG keys.
Alerts:	Ubuntu USN-1666-1 2012-12-17

Comments (none posted)

drupal6-ctools: cross-site scripting

Package(s):	drupal6-ctools	CVE #(s):	CVE-2012-5559
Created:	December 19, 2012	Updated:	December 19, 2012
Description:	From the Red Hat bugzilla entry: The Chaos tool suite is primarily a set of APIs and tools to improve the developer experience. The page manager node view task does not sufficiently escape node titles when setting the page title, allowing XSS. This vulnerability is partially [mitigated] by the node task being disabled by default and limited to users that have the ability to submit or edit nodes.
Alerts:	Fedora FEDORA-2012-19464 2012-12-13 Fedora FEDORA-2012-19449 2012-12-13

Comments (none posted)

kernel: denial of service

Package(s):	kernel	CVE #(s):	CVE-2012-5517
Created:	December 19, 2012	Updated:	December 20, 2012
Description:	From the Red Hat advisory: A NULL pointer dereference flaw was found in the way a new node's hot added memory was propagated to other nodes' zonelists. By utilizing this newly added memory from one of the remaining nodes, a local, unprivileged user could use this flaw to cause a denial of service.
Alerts:	Red Hat RHSA-2012:1580-01 2012-12-18 CentOS CESA-2012:1580 2012-12-19 Scientific Linux SL-kern-20121219 2012-12-19 Ubuntu USN-1669-1 2012-12-18 Ubuntu USN-1671-1 2012-12-18 Ubuntu USN-1670-1 2012-12-18 Ubuntu USN-1673-1 2012-12-18 Oracle ELSA-2012-1580 2012-12-19 Oracle ELSA-2012-2047 2012-12-20 Oracle ELSA-2012-2047 2012-12-20 Ubuntu USN-1677-1 2012-12-20 Ubuntu USN-1678-1 2012-12-20 Ubuntu USN-1679-1 2012-12-20 Ubuntu USN-1704-1 2013-01-22 Ubuntu USN-1704-2 2013-02-01 Oracle ELSA-2013-2507 2013-02-28

Comments (none posted)

librdmacm: bogus address resolution

Package(s):	librdmacm	CVE #(s):	CVE-2012-4516
Created:	December 17, 2012	Updated:	December 19, 2012
Description:	From the Red Hat bugzilla: A security flaw was found in the way librdmacm, a userspace RDMA Communication Managment API allowing to specify connections using TCP/IP addresses even though it opens RDMA specific connections, performed binding to the underlying ib_acm service (librdmacm used default port value of 6125 to bind to ib_acm service). An attacker able to run a rogue ib_acm service could use this flaw to make librdmacm applications to use potentially bogus address resolution information.
Alerts:	Fedora FEDORA-2012-19892 2012-12-15

Comments (none posted)

mate-settings-daemon: insecure timezones

Package(s):	mate-settings-daemon	CVE #(s):	CVE-2012-5560
Created:	December 17, 2012	Updated:	March 4, 2013
Description:	From the Red Hat bugzilla: mate-settings-daemon's datetime mechanism provides a D-Bus method to set the timezone, which is guarded by polkit's action org.mate.settingsdaemon.datetimemechanism.settimezone; this has the default policy "auth_self_keep", which allows any local user to perform the operation with only knowing their own password. This seems not to be currently exposed in the mate UI, but it is available through manual D-Bus calls, e.g. > dbus-send --system --print-reply --type=method_call --dest=org.mate.SettingsDaemon.DateTimeMechanism / org.mate.SettingsDaemon.DateTimeMechanism.SetTimezone string:/usr/share/zoneinfo/Cuba Because the time zone setting is a global resource, it should be restricted to system administrators (== root or users in the "wheel" group), by having a policy auth_admin_*. That's also what the other timezone setting mechanisms (in systemd and control-center) do.
Alerts:	Fedora FEDORA-2012-19726 2012-12-15 Fedora FEDORA-2013-2784 2013-03-03 Fedora FEDORA-2013-2766 2013-03-03

Comments (none posted)

nova: information disclosure

Package(s):	nova	CVE #(s):	CVE-2012-5625
Created:	December 19, 2012	Updated:	December 19, 2012
Description:	From the Ubuntu advisory: Eric Windisch discovered that Nova did not properly clear LVM-backed images before they were reallocated which could potentially lead to an information leak. This issue only affected setups using libvirt LVM-backed instances.
Alerts:	Ubuntu USN-1663-1 2012-12-12 Red Hat RHSA-2013:0208-01 2013-01-30

Comments (none posted)

pki-core: cross-site scripting

Package(s):	pki-core	CVE #(s):	CVE-2012-4543
Created:	December 17, 2012	Updated:	March 11, 2013
Description:	From the Red Hat bugzilla: Multiple cross-site scripting (XSS) flaws were found in the way: 1) 'displayCRL' script of Certificate System sanitized content of 'pageStart' and 'pageSize' variables provided in the query string, 2) 'profileProcess' script of Certificate System sanitized content of 'nonce' variable provided in the query string. A remote attacker could provide a specially-crafted web page that, when visited by an unsuspecting Certificate System user would lead to arbitrary HTML or web script execution in the context of Certificate System user session.
Alerts:	Fedora FEDORA-2012-20220 2012-12-15 Fedora FEDORA-2012-20243 2012-12-21 Red Hat RHSA-2013:0511-02 2013-02-21 Oracle ELSA-2013-0511 2013-02-25 Scientific Linux SL-pki--20130228 2013-02-28 CentOS CESA-2013:0511 2013-03-09

Comments (none posted)

qt: information disclosure

Package(s):	qt	CVE #(s):	CVE-2012-5624
Created:	December 19, 2012	Updated:	January 23, 2013
Description:	From the Red Hat bugzilla entry: An information disclosure flaw was found in the way XMLHttpRequest object implementation in Qt, a software toolkit for developing applications, performed management of certain HTTP responses. Previous implementation allowed redirection from HTTP protocol to file schemas. Also the redirection handling was performed automatically by QML application and could not be disabled. A remote attacker could use this flaw to cause QML application in an unauthorized way to read local file content by causing the HTTP response for the application to be a redirect to a file: URL (file scheme).
Alerts:	Fedora FEDORA-2012-19759 2012-12-13 Fedora FEDORA-2012-19715 2012-12-21 openSUSE openSUSE-SU-2013:0143-1 2013-01-23 openSUSE openSUSE-SU-2013:0154-1 2013-01-23 openSUSE openSUSE-SU-2013:0157-1 2013-01-23 Ubuntu USN-1723-1 2013-02-14 Mageia MGASA-2013-0053 2013-02-16

Comments (none posted)

squashfs-tools: two code execution flaws

Package(s):	squashfs-tools	CVE #(s):	CVE-2012-4024 CVE-2012-4025
Created:	December 19, 2012	Updated:	January 7, 2013
Description:	From the Red Hat bugzilla entries [1, 2]: CVE-2012-4024: Stack-based buffer overflow in the get_component function in unsquashfs.c in unsquashfs in Squashfs 4.2 and earlier allows remote attackers to execute arbitrary code via a crafted list file (aka a crafted file for the -ef option). NOTE: probably in most cases, the list file is a trusted file constructed by the program's user; however, there are some realistic situations in which a list file would be obtained from an untrusted remote source. CVE-2012-4025: Integer overflow in the queue_init function in unsquashfs.c in unsquashfs in Squashfs 4.2 and earlier allows remote attackers to execute arbitrary code via a crafted block_log field in the superblock of a .sqsh file, leading to a heap-based buffer overflow.
Alerts:	Fedora FEDORA-2012-19227 2012-12-13 Fedora FEDORA-2012-19203 2012-12-13 Mageia MGASA-2013-0001 2013-01-05

Comments (none posted)

tomcat: multiple vulnerabilities

Package(s):	tomcat	CVE #(s):	CVE-2012-4534 CVE-2012-4431 CVE-2012-3546
Created:	December 19, 2012	Updated:	January 24, 2013
Description:	From the CVE entries: org/apache/tomcat/util/net/NioEndpoint.java in Apache Tomcat 6.x before 6.0.36 and 7.x before 7.0.28, when the NIO connector is used in conjunction with sendfile and HTTPS, allows remote attackers to cause a denial of service (infinite loop) by terminating the connection during the reading of a response. (CVE-2012-4534) org/apache/catalina/filters/CsrfPreventionFilter.java in Apache Tomcat 6.x before 6.0.36 and 7.x before 7.0.32 allows remote attackers to bypass the cross-site request forgery (CSRF) protection mechanism via a request that lacks a session identifier. (CVE-2012-4431) org/apache/catalina/realm/RealmBase.java in Apache Tomcat 6.x before 6.0.36 and 7.x before 7.0.30, when FORM authentication is used, allows remote attackers to bypass security-constraint checks by leveraging a previous setUserPrincipal call and then placing /j_security_check at the end of a URI. (CVE-2012-3546)
Alerts:	Fedora FEDORA-2012-20151 2012-12-19 openSUSE openSUSE-SU-2012:1701-1 2012-12-27 openSUSE openSUSE-SU-2012:1700-1 2012-12-27 Ubuntu USN-1685-1 2013-01-14 Mageia MGASA-2013-0015 2013-01-18 openSUSE openSUSE-SU-2013:0147-1 2013-01-23 openSUSE openSUSE-SU-2013:0170-1 2013-01-23 openSUSE openSUSE-SU-2013:0161-1 2013-01-23 openSUSE openSUSE-SU-2013:0192-1 2013-01-23 Red Hat RHSA-2013:0623-01 2013-03-11 CentOS CESA-2013:0623 2013-03-12 Oracle ELSA-2013-0623 2013-03-11 Scientific Linux SL-tomc-20130312 2013-03-12 Red Hat RHSA-2013:0640-01 2013-03-12 CentOS CESA-2013:0640 2013-03-12 Oracle ELSA-2013-0640 2013-03-13 Scientific Linux SL-tomc-20130312 2013-03-12

Comments (none posted)

unity-firefox-extension: information disclosure

Package(s):	unity-firefox-extension	CVE #(s):	CVE-2012-0958
Created:	December 19, 2012	Updated:	December 19, 2012
Description:	From the Ubuntu advisory: It was discovered that unity-firefox-extension bypassed the same origin policy checks in certain circumstances. If a user were tricked into opening a malicious page, an attacker could exploit this to steal confidential data or perform other security-sensitive operations.
Alerts:	Ubuntu USN-1665-1 2012-12-13

Comments (none posted)

Page editor: Jake Edge

Kernel development

Brief items

Kernel release status

The 3.8 merge window is still open and patches continue to flow into the mainline repository. See the separate article below for a summary of significant changes for 3.8.

Stable updates: 3.0.57, 3.4.24, 3.6.11 and 3.7.1 were all released on December 17. Note that 3.6.11 is the last planned 3.6 update.

Comments (none posted)

Quotes of the week

— Android Authority has a less-than-authoritative moment.

— Linus Torvalds

Comments (1 posted)

Kernel development news

3.8 Merge window part 2

Linus has been busy in the last week; as of this writing, some 6200 changesets have been pulled into the mainline repository since last week's summary. As a result, just over 10,000 changes have been merged overall, making 3.8 the busiest merge window ever and the first to exceed 10,000 patches. And the merging process is not done yet.

Quite a few significant changes have been merged. Among other things, we have seen a decision made on how the development of better NUMA balancing will proceed. Without further ado, the most significant user-visible changes merged in the last week include:

• The disagreement over how the kernel's NUMA performance problems should be addressed was partially resolved when Ingo Molnar agreed that Mel Gorman's "balancenuma" patch set should be merged as a base for future development. Balancenuma is intended to get the fundamental infrastructure in place to allow experimentation with placement and migration policies; it adds little in the way of such policies itself. That base code has been merged for 3.8; expect policy-oriented code to be pushed for the 3.9 development cycle.

• The huge zero page feature has been merged, greatly reducing memory usage for some use cases.

• The kernel memory usage accounting infrastructure has been merged, allowing the placement of limitations on kernel memory use by any specific control group. See the updated Documentation/cgroups/memory.txt file for details on how to use this feature.

• The inline data patch set has been merged into the ext4 filesystem. Ext4 can now store data for small files directly in the inode, improving performance and space efficiency. Ext4 also now supports the SEEK_HOLE and SEEK_DATA lseek() operations.

• The Btrfs filesystem has a new "replace" operation to allow the efficient replacement of a single drive in a volume.

• The tmpfs filesystem now supports the SEEK_HOLE and SEEK_DATA lseek() operations.

• The user namespace completion patch set has been pulled. Eric Biederman says: "This set of changes adds support for unprivileged users to create user namespaces and as a user namespace root to create other namespaces. The tyranny of supporting suid root preventing unprivileged users from using cool new kernel features is broken."

• The new system call:

      int finit_module(int fd, const char *args, int flags);
  

  can be used to load a kernel module from the given file descriptor. This call was added by the ChromeOS developers so that they can accept or reject a module depending on where it is stored in the filesystem.

• The batman-adv mesh networking subsystem has gained distributed ARP table support.

• The tun/tap network driver and the virtio net driver both now support multiple queues per device.

• The QFQ packet scheduler has been upgraded to "QFQ+", which is said to be faster and more capable; see this paper [PDF] for details.

• The s390 architecture has gained support for attached PCI buses.

• UEFI boot-time variables are now accessible via the new "efivars" virtual filesystem.

• The ptrace() system call has a new option flag, PTRACE_O_EXITKILL, which causes all traced processes to receive a SIGKILL signal if the tracing process exits unexpectedly.

• New hardware support includes:
  • Audio: Wolfson Microelectronics WM8766 and WM8776 codecs, Philips PSC724 Ultimate Edge sound cards, Freescale / iVeia P1022 RDK boards, Maxim max98090 codecs, and Silicon Laboratories 476x AM/FM radio chips.

  • Block: LSI MPT Fusion SAS 3.0 host adapters, and Chelsio T4-based 10Gb adapters (FCoE offload support).

  • Graphics: NVIDIA Tegra20 display controllers and HDMI outputs.

  • Input: ION iCade arcade controllers, Wolfson Microelectronics "Arizona" haptics controllers, Roccat Lua gaming mice, TI ADC/touchscreen controllers, and Dialog Semiconductor DA9055 ONKEY controllers. The kernel has also gained support for human input devices connected via i²c as described in this document downloadable from Microsoft.

  • Miscellaneous: TI TPS51632 power regulators, TI TPS80031/TPS80032 power regulators, Versatile Express power regulators, Versatile Express hardware monitoring controllers, Maxim MAX8973 voltage regulators, Dialog Semiconductor DA9055 regulators, NXP Semiconductor PCF8523 realtime clocks (RTCs), Dialog Semiconductor DA9055 RTCs, CLPS711X host SPI controllers, Nvidia Tegra20/Tegra30 SLINK controllers, Nvidia Tegra20 serial flash controllers, Nokia RX-51 (N900) battery controllers, Solomon SSD1307 OLED controllers, Nano River Technologies Viperboard multifunction controllers, Nokia "Retu" multifunction controllers, AMS AS3711 power management chips, and Nokia CBUS-attached devices.

  • Network: CDC mobile broadband interface model USB-attached adapters, Atheros AR5523-based wireless adapters, Realtek RTL8723AE wireless adapters, Aeroflex Gaisler GRCAN and GRHCAN CAN controllers, and Kvaser CAN/USB interfaces.

  • Video4Linux: Samsung S3C24XX/S3C64XX SoC camera interfaces (full-memory write access not required).

In contrast with the large number of new features, the number of significant internal changes has been relatively small. Changes visible to kernel developers include:

• The Video4Linux2 layer now supports the use of shared DMA buffers for frame I/O. See the DocBook documentation for details on how to use this feature. Also: the videobuf2 subsystem now supports the use of scatterlists with user-space buffers in the "contiguous" DMA mode.

• The input subsystem supports the use of "managed" devices via the new devm_input_allocate_device() function.

One feature that has not been merged is RAID5/6 support for the Btrfs filesystem. Those patches are being prepared for the mainline, though, and can be expected in the 3.9 cycle. Meanwhile, the merge window could stay open until as late as December 24, though Linus has threatened to close it early. The final changes to be merged for 3.8 will be summarized once that closure has happened.

Comments (1 posted)

Virtualization and the perf ABI

Breaking the application binary interface (ABI) between the kernel and user space is a well-known taboo for Linux. That line may seem a little blurrier to some when it comes to the ABI for tools like perf that ship with the kernel. As a recent discussion on the linux-kernel mailing list shows, though, Linus Torvalds and others still have that line in sharp focus.

The issue stems from what appears to be a fairly serious bug in some x86 processors. Back in July, David Ahern reported that KVM-based virtual machines would crash when recording certain events on the host. On some x86 processors, the "Precise Events Based Sampling" (PEBS) mechanism can be used to gather precise counts of events like CPU cycles. Unfortunately, PEBS and hardware virtualization don't play nicely together.

As Ahern reported, running:

    perf record -e cycles:p -ag -- sleep 10

on the host would reliably crash all of the guests. That particular command will record the events specified, CPU cycles in this case, to a file; more information about perf can be found here. It turns out that PEBS incorrectly treats the contents of the Data Segment (DS) register as a guest address, rather than as a host address. That leads to memory corruption in the guest, which will crash all of the virtual machines on the system. The ":p" (precise) attribute on the cycles event (which can be repeated for higher precision levels as in cycles:pp) asks for more precise measurements, which leads to PEBS being used. Without that attribute, the cycle counts measured are less accurate, but do not cause the VM crashes.

That problem led Peter Zijlstra to change perf_event.c in the kernel to disallow precise measurements unless guest measurement has been specifically excluded. Using the ":H" (host-only) attribute will still allow precise measurements as perf will set the exclude_guest flag on the event. That flag will inhibit PEBS activity while in the guest. In addition, Ahern changed perf so that exclude_guest would be automatically selected if the "precise" attribute was set. There's just one problem with those solutions: existing perf binaries do not set exclude_guest, so users would get an EOPNOTSUPP error.

It turns out that one of those existing users is Torvalds, who complained that:

    perf record -e cycles:pp

no longer worked for him. Ahern suggested using "cycles:ppH", but that elicited an annoyed response from Torvalds. Why should he have to add a new flag to deal with virtualization, when he isn't running it? "That whole 'exclude_guest' test is insane when there isn't any virtualization going on."

Ahern countered that it's worse to have VMs explode because someone runs a precise perf. But that's beside the point, as Torvalds pointed out:

Forcing existing perf binary users to change their habits is the crux of the matter. Beyond breaking the ABI, which is clearly not allowed, it makes perf break for real users as Ingo Molnar said: "Old, working binaries are actually our _most_ important usecase: it's 99.9% of our current installed base ...". While it is certainly a problem that older kernels can have all their guests crashed with a simple command, the proper solution is not to require either upgrading perf or changing the flags (which could well be buried in scripts or other automation).

Existing perf binaries set the exclude_guest flag to zero, while binaries that have Ahern's change set it to one. That means newer kernels that seek to fix the crashing guest bug cannot rely on a particular value for that flag. The "proper" way to have handled the problem is to use a new include_guest flag (or similar), which defaults to zero. Older binaries cannot change that flag (since they don't know about it), so the kernel code can use it to exclude the precise flag for guests on x86 systems. Other architectures may not suffer from the same restriction.

Beyond that, Torvalds argues that if the user asks for a precise measurement but doesn't specify either the "H" or "G" (include guests) attribute, the code should try to do the right thing. That means it should measure both the host and guests on systems that support it, while backing off to just the host for x86. Meanwhile it could return EOPNOTSUPP if the user explicitly asks for a broken combination (e.g. precise and include guests on x86). Molnar concurred. Ahern seemed a bit unhappy about things, but said that he would start working on a patch that has not appeared yet.

It is worth noting that Torvalds admitted that he could trivially recompile perf to get around the whole problem; it was a principle that he was standing up for. Even though some tools like perf are distributed with the kernel tree, that does not relax the "no regressions" rule. Some critics of the move to add tools to the kernel tree were concerned that it would facilitate ABI changes that could be glossed over by requiring keeping the tools and kernel in sync. This discussion clearly shows that not to be the case.

Having a way to crash all the VMs on a system is clearly undesirable, but as Torvalds pointed out, that had been true for quite some time. Undesirable behavior does not rise to the level of allowing ABI breakage, however. In addition, distributions and administrators can always limit access to perf to the root user—though that obviously may still lead to unexplained VM crashes as Ahern noted. Molnar pointed out that the virtualization use case is a much smaller piece of the pie, so making everyone else pay for a problem they may never encounter just doesn't make sense. Either through a patch or a revert, it would seem that the "misbehavior" will disappear before 3.8 is released.

Comments (none posted)

Removing uninitialized_var()

Compiler warnings can be life savers for kernel developers; often a well-placed warning will help to avert a bug that, otherwise, could have been painful to track down. But developers quickly tire of warnings that appear when the relevant code is, in fact, correct. It does not take too many spurious warnings to cause a developer to tune out compiler warnings altogether. So developers will often try to suppress warnings for correct code — a practice which can have undesirable effects in the longer term.

GCC will, when run with suitable options, emit a warning if it believes that the value of a variable might be used before that variable is set. This warning is based on the compiler's analysis of the paths through a function; if it believes it can find a path where the variable is not initialized, an "uninitialized variable" warning will result. The problem is that the compiler is not always smart enough to know that a specific path will never be taken. As a simple example, consider uhid_hid_get_raw() in drivers/hid/uhid.c:

    size_t len;
    /* ... */
    return ret ? ret : len;

A look at the surrounding code makes it clear that, in the case where ret is set to zero, the value of len has been set accordingly. But the compiler is unable to figure that out and warns that len might be used in an uninitialized state.

The obvious response to such a warning is to simply change the declaration of len so that the variable starts out initialized:

    size_t len = 0;

Over the years, though, this practice has been discouraged on the kernel mailing lists. The unneeded initialization results in larger code and a (slightly) longer run time. And, besides, it is most irritating to be pushed around by a compiler that is not smart enough to figure out that the code is correct; Real Kernel Hackers don't put up with that kind of thing. So, instead, a special macro was added to the kernel:

    /* <linux/compiler-gcc.h> */
    #define uninitialized_var(x) x = x

It is used in declarations in this manner:

    size_t uninitialized_var(len);

This macro has the effect of suppressing the warning, but it doesn't cause any additional code to be generated by the compiler. This macro has proved reasonably popular; a quick grep shows over 280 instances in the 3.7+ mainline repository. That popularity is not surprising: it allows a kernel developer to turn off a spurious warning and to document the fact that the use of the variable is, indeed, correct.

Unfortunately, there are a couple of problems with uninitialized_var(). One is that, at the same time that it is fooling GCC into thinking that the variable is initialized, it is also fooling it into thinking that the variable is used. If the variable is never referenced again, the compiler will still not issue an "unused variable" warning. So, chances are, there are a number of excess variables that have not been removed because nobody has noticed that they are not actually used. That is a minor irritation, but one could easily decide that it is tolerable if it were the only problem.

The other problem, of course, is that the compiler might just be right. During the 3.7 merge window, a patch was merged that moved some extended attribute handling code from the tmpfs filesystem into common code. In the process of moving that code, the developer noticed that one variable initialization could be removed, since, it seemed, it would pick up a value in any actual path through the function. GCC disagreed, issuing a warning, so, when this developer wrote a second patch to remove the initialization, he also suppressed the warning with uninitialized_var(). Unfortunately, GCC knew what it was talking about in this case; that code had just picked up a bug where, in a specific set of circumstances, an uninitialized value would be passed to kfree() with predictably pyrotechnic results. That bug had to be tracked down by other developers; it was fixed by David Rientjes on October 17. At that time, Hugh Dickins commented that it was a good example of how uninitialized_var() can go wrong.

And, of course, this kind of problem need not be there from the outset. The code for a given function might indeed be correct when uninitialized_var() is employed to silence a warning. Future changes could introduce a bug that the compiler would ordinarily warn about, except that the warning will have been suppressed. So, in a sense, every uninitialized_var() instance is a trap for the unwary.

That is why Linus threatened to remove it later in October, calling it "an abomination" and saying:

In response, Ingo Molnar put together a patch removing uninitialized_var() outright. Every use is replaced with an actual initialization appropriate to the type of the variable in question. A special comment ("/* GCC */") is added as well to make the purpose of the initialization clear.

The patch was generally well received and appears to be ready to go. In October, Ingo said that he would keep it out of linux-next (to avoid creating countless merge conflicts), but would post it for merging right at the end of the 3.8 merge window. As of this writing, that posting has not occurred, but there have been no signs that the plans have changed. So, most likely, the 3.8 kernel will lack the uninitialized_var() macro and developers will have to silence warnings the old-fashioned (and obviously correct) way.

Comments (20 posted)

Patches and updates

Kernel trees

• Greg KH: Linux 3.7.1 . (December 17, 2012)

• Greg KH: Linux 3.6.11 . (December 17, 2012)

• Greg KH: Linux 3.4.24 . (December 17, 2012)

• Greg KH: Linux 3.0.57 . (December 17, 2012)

Build system

• rob@landley.net: build 3.7 kernel without perl . (December 18, 2012)

• Ulf Magnusson: [ANNOUNCE] Kconfiglib: a flexible Python Kconfig parser and library - now on GitHub . (December 18, 2012)

Core kernel code

• Matthias Kohler: Multiple run-queues for BFS . (December 17, 2012)

• Con Kolivas: 3.7-ck1, BFS 426 for linux-3.7 . (December 17, 2012)

• Sasha Levin: userns: use new hashtable implementation . (December 17, 2012)

Development tools

• Alexander Gordeev: IRQ-bound performance events . (December 17, 2012)

• Namhyung Kim: perf report: Add support for event group view (v7) . (December 17, 2012)

Device drivers

• Terje Bergstrom: Support for Tegra 2D hardware . (December 13, 2012)

• Naveen Krishna Chatradhi: i2c: Implement generic gpio based bus arbitration . (December 14, 2012)

• Roland Stigge: gpio: Add block GPIO . (December 17, 2012)

• Fabio Baltieri: tx/rx LED trigger support . (December 17, 2012)

• Daniel Jeong: regulator: new driver for LP8755 . (December 17, 2012)

• Sjur Brændeland: remoteproc: Support bi-directional vdev config space . (December 17, 2012)

• Toshi Kani: Hot-plug and Online/Offline framework . (December 17, 2012)

• Arto Meriläinen: NVIDIA Tegra support . (December 17, 2012)

• Rob Clark: drm/lcdc: add TI LCD Controller DRM driver . (December 17, 2012)

• Tomi Valkeinen: Common Display Framework-T . (December 17, 2012)

• Christopher Heiny: input: Synaptics RMI4 Touchscreen Driver . (December 19, 2012)

• Boris BREZILLON: pwm: atmel: add Timer Counter Block PWM driver . (December 19, 2012)

• Alan Cox: goldfish: base support . (December 19, 2012)

Documentation

• Hans Verkuil: RFCv2: Second draft of guidelines for submitting patches to linux-media . (December 17, 2012)

Filesystems and block I/O

• Darrick J. Wong: [PATCH v2.3 0/3] mm/fs: Implement faster stable page writes on filesystems . (December 13, 2012)

• Maxim V. Patlasov: fuse: process direct IO asynchronously . (December 17, 2012)

• Tejun Heo: block: implement blkcg hierarchy support in cfq . (December 17, 2012)

• Eric Wong: fadvise: perform WILLNEED readahead in a workqueue . (December 17, 2012)

• clinew@linux.vnet.ibm.com: [RFC v2] Btrfs: Subpagesize blocksize (WIP). . (December 18, 2012)

Memory management

• Minchan Kim: Support volatile for anonymous range . (December 18, 2012)

Networking

• Vlad Yasevich: Add basic VLAN support to bridges . (December 19, 2012)

Architecture-specific

• Yinghai Lu: x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G . (December 14, 2012)

• stefani@seibold.net: Add 32 bit VDSO time function support . (December 18, 2012)

• Varun Sethi: iommu/fsl: Freescale PAMU driver and IOMMU API implementation. . (December 14, 2012)

• Marc Zyngier: KVM on arm64 . (December 19, 2012)

• Catalin Marinas: arm64: ARMv8 RTSM model SoC support . (December 19, 2012)

Security-related

• Mimi Zohar: ima: enforcing appraise type . (December 18, 2012)

• Casey Schaufler: LSM: Multiple concurrent LSMs . (December 19, 2012)

Virtualization and containers

• Paolo Bonzini: Multiqueue virtio-scsi, and API for piecewise buffer submission . (December 18, 2012)

• Luiz Capitulino: auto-ballooning prototype (guest part) . (December 19, 2012)

Miscellaneous

• Karel Zak: util-linux v2.22.2 . (December 13, 2012)

Page editor: Jonathan Corbet

Distributions

Fedora ponders Software Collections

A feature in Red Hat Enterprise Linux (RHEL) that supports multiple, parallel installations of programming languages and other normally system-wide tools was recently discussed on the fedora-devel mailing list. Matthew Miller, who recently started as the Fedora cloud architect, raised the idea of bringing Software Collections from RHEL to Fedora. The idea behind Software Collections is interesting, but no clear consensus on how appropriate they might be for Fedora emerged. As with many Fedora discussions of late, this one at least partly comes back to the question of the role that the distribution is meant to fill.

The problem that Miller initially presented is particularly acute in the Ruby and Java worlds, though Python and other tools (e.g. databases) sometimes suffer from it as well. Various packages may depend on different versions of the underlying tools, which makes it difficult to have them coexist on the same system. As an example he noted that the Fedora packages for the Puppet configuration management tool are broken because the Fedora Ruby version is too new. One way to solve that problem is to have multiple Ruby versions available that can be installed in parallel and chosen at runtime. That's exactly the problem that Software Collections sets out to solve.

A Software Collection (SC) uses the same packaging tools (RPM, Yum) already used by RHEL and Fedora, but installs the packages and their dependencies in the /opt/provider hierarchy. The provider piece is a specific string assigned to a vendor, which will allow multiple software providers to share the hierarchy without name collisions. There is also an scl tool that allows choosing one or more SCs to be active when running a specific command. Whatever is needed in the environment for the particular SC will be set up by "scriptlets" that get installed with the collection and are run when the SC is selected.

As Miller notes, there is nothing inherent in Java or Ruby that leads to version-mismatch problems, instead they are caused by the expectations of developers building software using those languages. There is a strong preference for bundling various toolkits and libraries with such packages, which runs counter to the way Fedora and many other distributions do things. Red Hat Eclipse team member Alexander Kurtakov put it more bluntly:

But, the fast-paced nature of Fedora (normally a release every six months or so) may not make for a good match with SCs. Former Fedora project leader Jared Smith was a bit skeptical about the fit:

Miller had a ready answer. He outlined three separate uses he saw for SCs in Fedora, starting with handling problems like the Puppet issue. Allowing multiple languages would give more choices for Fedora as a development platform. He also noted that RHEL and Fedora make up an ecosystem where developers targeting the former may well be developing on the latter. Access to SCs on Fedora might be quite useful since they are available for RHEL. Those two potential use cases did not require too much discussion, but the other one did:

Bill Nottingham responded with a self-proclaimed "heretical" suggestion that Fedora be turned into a much smaller platform, with packages from the "grand Fedora universe" that target one or more of those platform releases. In that model, the enormous pile of software that Fedora deals with for each release would be greatly reduced. Miller and others—notably enterprise-leaning participants—looked favorably on the heresy, but it was recognized that it would be a difficult direction for Fedora to take.

There are, of course, downsides to managing software via SCs. The "library bundling problem" comes to mind, for example. If multiple SCs all include a library (or other component) that needs to be upgraded for security reasons, it may require a great deal of work. One could imagine several different vulnerable versions of a library lurking in SCs that are still being used. Each of those needs to be fixed and all of the SCs need to be updated. For RHEL, that's par for the course, but Fedora has generally moves on before those kinds of problems become acute.

The conversation soon pivoted from Nottingham's suggestion to whether SCs might help external projects or companies in making their software available for Fedora. By providing a stable platform and a way for those entities to bundle up and install all of the needed pieces, more software might be made available for Fedora. Much of that software is, of course, proprietary, but there are advocates for making Fedora an easier target for those kinds of applications.

One of the problems that Fedora has faced over the years is the explosion of packages that it tries to maintain, test, and release in a short six-month time frame. Several commenters pointed to SCs (or something like them) as a way to decouple Fedora from that enormous list of packages. Projects could target Fedora, without actually becoming part of Fedora, as Fenando Nasser suggested.

Those kinds of ideas hearken back to an earlier arrangement for the Fedora distribution. While Adam Williamson's humorous idea of a return to Fedora Core and Fedora Extras was not taken seriously, some kind of similar split seemed to gain quite a bit of traction in the discussion. Whether it goes any further than that down the road remains to be seen, but SCs could potentially help the process if it does.

There are logistical and licensing questions—along with plenty of others—that would have to be resolved, of course. If there were a split, how would non-core (for lack of a better term) components manage their SCs and repositories? If they were under the Fedora umbrella, the distribution would have some responsibility for the contents of the packages. If they were not under the umbrella, users would have to somehow enter those repositories into their Yum configuration. Richard Jones outlined a number of issues that would need to be resolved under such a system.

While the conversation veered in a direction that Miller may not have expected, it does give an interesting view into the thinking of some (many?) in the Fedora development community. Some of the interest in a fairly radical change may come from frustration with the delays in the Fedora 18 cycle, but there seems to be more to it than that. For some time now, Fedora has been trying to find (or define) its niche. This conversation is another step along that path.

Comments (15 posted)

Brief items

Distribution quotes of the week

-- Greg Kroah-Hartman

-- Richard Yao

Comments (none posted)

CyanogenMod 10.1 nightly builds available

We recently complained that CyanogenMod builds based on the Android 4.2 release were not available for most devices, meaning that CyanogenMod lacked features found in stock Android builds. So it seems only fair to point out that the CyanogenMod nightly builds page now includes CM10.1-based (and, thus, Android 4.2-based) builds for a wide variety of targets. CM10.1 works well on the Nexus 7 tablet, with no real problems found so far.

(Just be sure to install updated Google Apps as well or things will not go well...not that your editor would ever make such a mistake.)

Comments (7 posted)

IPFire 2.11 - Core Update 65

IPFire 2.11 core update 65 will be the last release in the 2.x series. IPFire is a hardened Linux appliance distribution designed for use as a firewall. New features include a GUI to configure OpenVPN roadwarrior clients individually and OpenVPN path MTU discovery.

Full Story (comments: none)

PC-BSD 9.1 Now Available

The PC-BSD team has announced that PC-BSD 9.1 is now available. "This release includes many exciting new features and enhancements, such as a vastly improved system installer, ZFS “Boot Environment” support, TrueOS (A FreeBSD based server with additional power-user utilities), and much more!"

Comments (2 posted)

Distribution News

Fedora

Fedora Project OpenID Security issue

A bug was discovered in the Fedora Project OpenID provider on December 12. The bug was pulled in with a fix on October 23 and patched December 12, shortly after its discovery. "While the bug was present, anyone with a valid Fedora Account System (FAS) account who tried to log into a remote website using any FAS OpenID identity would have that identity validated by FAS even if the identity belonged to a *different FAS user*. The fix we put in place rejects the attempt if the user who logs in does not own the identity that they requested." Potentially affected accounts have been notified.

Full Story (comments: none)

openSUSE

The New 2013 openSUSE Board Members

The openSUSE Board election is over. Raymond Wooninck (tittiacoke) and Robert Schweikert (robjo) will join the board on the January 9 transitional meeting.

Full Story (comments: none)

Newsletters and articles of interest

Distribution newsletters

• DistroWatch Weekly, Issue 487 (December 17)
• Maemo Weekly News (December 17)
• Ubuntu Weekly Newsletter, Issue 296 (December 16)

Comments (none posted)

Univention Corporate Server 3.1 with Active Directory functionality (The H)

Univention has released version 3.1 of its Univention Corporate Server (UCS). The H takes a look at this release. "The server distribution offers Active-Directory-compatible domain services using Samba 4. The new Univention App Centre simplifies the installation of third-party products such as groupware, document management and backup solutions; the app catalogue provides an overview of available applications."

Comments (none posted)

Page editor: Rebecca Sobol

Development

A preview of Inkscape 0.49

The Inkscape vector graphics editor is approaching its next milestone release, version 0.49. As always, the update rolls together a wealth of new tools and features. This development cycle is relatively light on large-scale additions, but there is a long list of small usability enhancements that will add up to a smoother design experience for most users.

The project just released a bugfix to the stable 0.48 series, and although Inkscape is decidedly a "released when ready" application, the murmuring is that Inkscape 0.49 could hit virtual shelves as soon as January 2013. In the meantime, there are fairly stable nightly builds available from the trunk for those who wish to experiment.

Drawing

Two new tools debut in Inkscape 0.49. The first is the measure tool, a long-awaited addition that has applications in computer-aided drafting (CAD) and other drawing tasks that require precision object placement. As is the case with most graphics applications, one can measure an object by clicking with the tool and dragging out a line. However, where a raster application like Gimp can only measure the length of the line segment defined by the mouse movement, Inkscape measures the distance between drawing objects. Wherever the measure tool's line intersects a path or object, an "x" appears, and the tool overlays the distance in pixels between intersections, the total distance if there are multiple intersections, and the angle of the line.

The other new tool is the PowerStroke pen previewed at Libre Graphics Meeting (LGM) 2012, which we discussed in May. PowerStroke is an effect that produces calligraphy-like lines that change width, much like hand-inked pen or brush strokes. Of course, the advantage of using an Inkscape tool rather than actual ink is that the paths drawn as well as their attributes are fully adjustable after the fact. PowerStroke is better integrated now than it was at LGM, with improvements to the sometimes tricky joints at sharp corners.

Several of the existing tools pick up noteworthy features in this release. The node editor (which allows the user to adjust and edit the on-curve points and control points of Bézier splines) can now automatically add points at the curve's maxima and minima. Not every design task is improved by ensuring that a curve has points at its extrema, but there are a lot of scenarios where it makes calculations easier — consider calculating the bounding box of a path, for example. Consequently, having curve points at the extrema is sometimes required, and having Inkscape create them with one click is a genuine time-saver.

The gradient editor has been reworked. In previous releases, editing a gradient opened a floating window in which one could add or remove gradient stops and adjust colors. The new editor works on-canvas, with add/remove buttons and a color selection widget on the toolbar. The "snap to" functionality is not a tool in its own right, but over the past few releases, Inkscape's snapping has evolved into a complex beast. New in this release is the ability to set snap-to-path-intersection and snap-to-guide-intersection, plus the ability to snap a path perpendicularly or tangentially while drawing it. Snapping to text is also improved.

Similarly, Inkscape's new "symbols library" is not a tool per se, though it does add functionality. The library is based on SVG's <symbol> element, which is used to define reusable graphical objects. One could always duplicate a normal SVG object, of course, but the idea is that SVG can be used to create common collections of frequently-referenced symbols, in the same way that named colors can simplify SVG documents that need to reuse identical color in multiple spots. Whether one finds that idea enticing or not, Inkscape can now take advantage of it, providing access to "libraries" of symbols and enabling users to create their own. Two symbol libraries are built in: one with logic gates, and the other with international road and travel symbols.

Beyond the basic tools, a handful of new extensions is included that also offer new functionality. Inkscape extensions tend to be more task-centric, so not every user will find them helpful, but they can also offer surprisingly sophisticated features. For example, one new extension allows N-up page layout for printing large documents. Another allows converting drawings to the G-code format used by computer-controlled cutting machines. There are also extensions for generating QR codes, isometric grids, and Voronoi diagrams, plus smaller extensions to replace fonts in a document, extract text, and the "guillotine," which can split a drawing up with guide lines to export it as multiple PNG images.

Environmental and usability tweaks

In practice, Inkscape's tool set is extensive enough that it can be mind-boggling to hear that some users still find it lacking, but such is the lot of the general-purpose creative application. On the other hand, the diverse tool set can frequently result in enough complexity that the application begins to get in the way. On that front, the project is making frequent small improvements that fix minor annoyances.

For instance, layers have often felt like an afterthought in Inkscape. The layer controls are small and tucked away at the bottom of the window. Changing layer visibility or order was not intuitive. Inkscape 0.49 improves things by allowing the user to re-order layers with a simple drag-and-drop. Gimp and Krita still provide a nicer layers interface (in Inkscape, a drawing's layers are listed in a drop-down selection widget, rather than a list with all layers visible at once), but the fix is an improvement.

Selecting the right object from a position where multiple objects are stacked or overlap has been another pain point; Inkscape 0.49 allows the user to cycle through the options at the cursor point using the mouse scroll-wheel. Users can also increase the size of the "handles" shown for grabbing and manipulating path nodes, toggle the visibility of guides, and edit keyboard shortcuts. Inkscape will now remember from session to session which tool palettes are open and their various screen positions, too, eliminating the need to reconfigure the application at every start-up.

A particularly novel feature is the ability to enter arithmetic operations into spinboxes. For example, if a rectangle is 1071 pixels wide and needs to be shrunk to 1/7 of that size, the user can simply enter /7 into the width box and hit Return, rather than waste precious minutes hunting for a pencil or searching for the calculator in GNOME Shell's "Activities overview." The Inkscape wiki does not provide a canonical list of which calculations are supported, but it does provide examples with nested parentheses and even physical units (e.g., mm instead of pixels). No word yet on logarithms, infinite series, or complex numbers — mathematicians take note; this is clearly a feature in need of serious stress-testing....

There are also several improvements aimed at using Inkscape for print work. The background display color of the canvas can be changed without changing the color of the document itself. That would be useful, for example, if designing a flyer that will be printed on tan paper — one needs to see how the design will look against tan, but adding a solid-color rectangle as a background object is a kludge. The interface can be toggled between normal full-color display and grayscale, which again allows the user to preview output — although this feature has other uses; it is often a good idea to design a logo in grayscale first, to establish contrast and readability, and grayscale is important for supporting people color-impaired vision.

PDF and TeX export have been improved, which can benefit print or electronic output. The PDF exporter can now automatically add a "bleed" margin, and TeX export now supports text styles — including, font nerds will be happy to learn, distinguishing between oblique and italic styles. In addition, support for export to Gimp's XCF format has been improved, and it is now possible to export drawings to Flash XML Graphics (FXG), XAML, and to the native format for the open source vector animation application Synfig.

Over and out

The new Inkscape series is not all bling, however. There are a number of performance and rendering improvements rolled into 0.49, too. The first is the long-awaited merging of Google Summer of Code work from 2010 and 2011 that ported the rendering engine to the Cairo raster graphics library. This results in improved responsiveness when editing and closes a number of outstanding rendering bugs. Responsiveness is also improved through caching, and memory usage is reduced; the release notes cite a four-fold reduction in the memory required over Inkscape 0.48. Cairo is also responsible for the grayscale preview mode mentioned earlier, and is used as the PNG export engine.

The other under-the-hood change of significance is the addition of multithreading through OpenMP. This change is primarily felt through speed improvements when using filters; the OpenMP parallelization can take advantage of all CPU cores on the system. Inkscape implements many effects through SVG filters even when they are not labeled as such explicitly (such as the "blur" slider available on every object). In addition, each release adds more live previews to path effects and extensions. The upshot is that multithreading is likely to benefit a lot of users even if they do not employ complex filters in their normal workflow.

Overall, Inkscape 0.49 is shaping up to be a solid improvement. It is hard to generalize about the impact of features like Cairo rendering and multithreading; some users may feel no improvement at all, while others may be ecstatic. The same goes for the new tools and features — if you use G-code or TeX the benefits are clear, if you have some other design needs you might not even notice the new features. On the other hand, the usability improvements (particularly to selection and window management) are more or less universal. But the truly interesting aspect of any new Inkscape release is seeing how users will take to a new drawing mode like PowerStroke, because that is ultimately unpredictable. Inkscape is a "creative" application: its biggest enhancements are in how it allows end users to think, and act, a little more creatively with every new release.

Comments (12 posted)

Brief items

Quote of the week

— Bradley Kuhn

Comments (5 posted)

The eudev project launches

Eudev is the Gentoo-based fork of udev which was covered here in November. The project has now officially announced its existence. "udev often breaks compatibility with older systems by depending upon recent Linux kernel releases, even when such dependencies are avoidable. This became worse after udev became part of systemd, which has jeopardized our ability to support existing installations. The systemd developers are uninterested in providing full support in udev to systemd alternatives. These are problems for us and we have decided to fork udev to address them."

Full Story (comments: 190)

Qt 5.0 released

Digia, the current owner of the Qt code base, has sent out a press release announcing the Qt 5.0 release. "Key benefits of Qt 5 include: graphics quality; performance on constrained hardware; cross-platform portability; support for C++11; HTML5 support with QtWebKit 2; a vastly improved QML engine with new APIs; ease of use and compatibility with Qt 4 versions."

Comments (20 posted)

Status.net service to phase out, replaced by pump.io

Evan Prodromou of StatusNet announced that the company's microblog-hosting service running at the status.net domain will close to new customers over the coming weeks, as the company begins migrating its offerings from the StatusNet software to it successor, the just-unveiled pump.io. User accounts on the existing sites running from the status.net domain will continue to function, as will the Identi.ca site. Self-hosted StatusNet instances will be unaffected by the move.

Comments (64 posted)

PulseAudio 3.0 released

Version 3.0 of the PulseAudio subsystem is out; see the release notes for details. "The tl;dr version for the lazy is: easier setup when your device is a Bluetooth source, some ARM NEON optimisations, configurable latency offsets, ALSA UCM [use-case manager] support for embedded folks, and a _lot_ of other fixes and infrastructure changes."

Full Story (comments: none)

Gnumeric 1.12 released

Version 1.12 of the Gnumeric spreadsheet application is available. This is a major stable release wrapping up two years of development. Among the improvements are porting the interface to GTK+ 3, improved accuracy in computed cells, and additions to the graph tool. Gnumeric is also now available under two licenses, GPLv2 or GPLv3.

Full Story (comments: none)

Newsletters and articles

Development newsletters from the past week

• Caml Weekly News (December 18)
• What's cooking in git.git (December 12)
• What's cooking in git.git (December 16)
• What's cooking in git.git (December 18)
• Mozilla Hacks Weekly (December 13)
• Openstack Community Weekly Newsletter (December 14)
• Perl Weekly (December 17)
• PostgreSQL Weekly News (December 16)
• R Journal (December 14)
• Ruby Weekly (December 13)

Comments (none posted)

Fontana: What open source licensing could learn from Creative Commons (Opensource.com)

At Opensource.com, Red Hat's Richard Fontana expresses his admiration for the "coordinated, centralized manner in which CC licenses are conceived, drafted and revised, and the successful occupation of the full policy field of open and quasi-open content licensing by Creative Commons." By comparison, he says, the de-centralized and organic growth of free software licenses lacks the "great emphasis on simplification of use, understanding, and identification of the various license categories."

Comments (25 posted)

Perl: The First Twenty-Five Years

The Perl Foundation News has posted a detailed history of the first 25 years of the Perl language. "Before the advent of Perl 5 the resources for collecting these scripts were few and far between, and one or two have fallen into legend and are now taken out by wizened Perlers around a flickering light where the Tales of Terror are shared and Matt's Script Archive comes into its own magnificent glory. In these Enlightened days it is easy to mock those early pioneers and to smile fondly at some of the erroneous efforts, but they were the only resource of their time and they were formative in the evolution."

Comments (none posted)

Vernooij: Bazaar-NG: 7 years of hacking on a distributed version control system

At his blog, Jelmer Vernooij has written a detailed retrospective on the history of the Bazaar version control system, including a lot of analysis of the project's ups and downs over the years. "We just made these changes to the file format as they came along, rather than accumulating them. This meant that at one point there was a new format every couple of months. Later on, we did slow down on format changes and no new format has been introduced since 2009. Unfortunately we have been unable to shake the image that we introduce a new file format every fortnight."

Comments (32 posted)

Balazs: About Antiquated Metaphors in Icons

Björn Balazs reports on some surprising results from the recent LibreOffice Writer icon test, which (among other things) pitted Tango's "floppy disc" icon against Oxygen's "filing cabinet" icon for the save action. "The results are stunning. There was not the slightest problem with using the floppy disc, while the filing cabinet metaphor more or less failed [...] Even when looking at the group of young users the results do not change significantly and the antiquated floppy disc still scores a perfect 10.0." Balazs speculates on possible explanations; whatever the cause, surely additional interesting findings are still to come from this survey project.

Comments (4 posted)

Page editor: Nathan Willis

Announcements

Brief items

FSFE 2012 Annual Report

The Free Software Foundation Europe has published its annual report for 2012. "In order to be in charge of our own lives, we need to be able to control the computers we use. We can only do this if they run Free Software that we can use, study, share and improve. We can only do this if our computers aren't neutered to restrict their functionality, or loaded with spyware. We also need neutral networks to connect them to, so we can freely choose what to say, and to whom. With this in mind, 2012 was both a good and a bad year for our freedom."

Comments (none posted)

The Linux Foundation's year in review video

For those with 2.5 minutes to spare: the Linux Foundation has posted a video looking back at the most important Linux-related events (from its point of view) that happened in 2012.

Comments (13 posted)

Articles of interest

European Union's open source license to become compatible with GPLv3

The European Union's open source license, EUPL, will be revised to make it more compatible with GPLv3. The EUPL forum on Joinup is open for comments until mid-March 2013. "The main reason to update the licence is to remove barriers that could hinder others in the open source communities from using software licensed under the EUPL. "Making it explicitly compatible with the GPLv3 should increase interoperability", explains Patrice-Emmanuel Schmitz, a Brussels-based legal specialist working involved in the drafting of the EUPL. This should for instance make it easier to combine EUPL and GPLv3 software components or to use both licences to publish a project, says Schmitz. "It should also put an end to the categorisation by the Free Software Foundation of the EUPL as not fully GPL compatible."" (Thanks to Martin Michlmayr)

Comments (38 posted)

Author Gabriella Coleman Expands on Role of Linux in Hacker Culture (Linux.com)

Jennifer Cloer interviews Gabriella Coleman about her new book Coding Freedom: The Ethics and Aesthetics of Hacking. "To hack effectively requires the freedom to determine the shape, contour and direction of technological production. Freedom, in other words, is essential for quality. Sociologist Richard Sennet has has defined this drive in terms of “craftsmanship,” which is “an enduring, basic human impulse, the desire to do a job well for its own sake." It is not always easy to put this ethic into practice and open source hackers have figured out how to do so, using the right mix of law, tools and project governance to make it happen."

Comments (none posted)

Women in computing: An interview with Leslie Hawthorn (opensource.com)

Opensource.com has an interview with Leslie Hawthorn about the 2012 Grace Hopper Celebration of Women in Computing conference. "This has been the 3rd year that I've been involved in the Grace Hopper conference. Three years ago, in Atlanta, we had a group of folks come together and decided that it was kind of a bummer that there wasn't a lot of open source related content on the program. So, we got together a program committee and put on a full day of tracks related to contributing to open source software—everything from how you get started as a contributor to different projects you may wish to join, and how to get involved in open source if you're a student (from an academic point of view, how working in open source can enhance your career prospects)."

Comments (none posted)

Defence of the GPL realm (The H)

The H talks with Bradley Kuhn about GPL compliance. "Certainly we're in an era where lots of people are scrambling to create business models dancing around the issue of GPL compliance, and in using GPL enforcement in nefarious ways. Our community already has too much of that kind of activity, and I certainly don't want more of that. If, however, someone wanted to start another non-profit charity to do enforcement, I'd certainly welcome it and help them do it. I also encourage any individuals who hold copyrights in projects that Conservancy currently does active enforcement for – namely, BusyBox, Linux, and Samba – to get in touch with me and join our coalition. That's an easy way for those who hold copyrights to get involved with the work Conservancy's already doing in this area."

Comments (23 posted)

Calls for Presentations

GNU Tools Cauldron 2013 - Call for Abstracts

GNU Tools Cauldron will take place July 12-14, 2013, in Mountain View, California. The abstract submission deadline is February 28. "The purpose of this workshop is to gather all GNU tools developers, discuss current/future work, coordinate efforts, exchange reports on ongoing efforts, discuss development plans for the next 12 months, developer tutorials and any other related discussions."

Full Story (comments: none)

OSCON 2013 call for proposals

The 15th annual O'Reilly Open Source Convention (OSCON) will take place July 22-26, 2013 in Portland, Oregon. Proposals are due by February 4. There will be 20 full tracks covering all things open source.

Full Story (comments: none)

Upcoming Events

LCA: Inventor of the Web to Keynote

Sir Tim Berners-Lee will be a keynote speaker at the January 2013 linux.conf.au in Canberra. "Sir Tim Berners-Lee was knighted in 2004 for his work on HTTP and the World Wide Web, and was elected as a foreign associate of the United States Academy of Sciences in 2009. He also holds the Founders Chair at MIT's Computer Science and Artificial Intelligence Laboratory. This is Sir Tim Berners-Lee's first visit to Australia, and his linux.conf.au keynote speech is set to be the only technical talk during his Down Under tour."

Full Story (comments: none)

Events: December 20, 2012 to February 18, 2013

The following event listing is taken from the LWN.net Calendar.

Date(s)	Event	Location
December 27 December 29	SciPy India 2012	IIT Bombay, India
December 27 December 30	29th Chaos Communication Congress	Hamburg, Germany
December 28 December 30	Exceptionally Hard & Soft Meeting 2012	Berlin, Germany
January 18 January 19	Columbus Python Workshop	Columbus, OH, USA
January 18 January 20	FUDCon:Lawrence 2013	Lawrence, Kansas, USA
January 20	Berlin Open Source Meetup	Berlin, Germany
January 28 February 2	Linux.conf.au 2013	Canberra, Australia
February 2 February 3	Free and Open Source software Developers' European Meeting	Brussels, Belgium
February 15 February 17	Linux Vacation / Eastern Europe 2013 Winter Edition	Minsk, Belarus

If your event does not appear here, please tell us about it.

Page editor: Rebecca Sobol