Search Results: "spa"

26 April 2016

Steinar H. Gunderson: Full stack

As I'm nearing the point where Nageru, my live video mixer, can produce a stream directly that is actually suitable to streaming directly to clients (without a transcoding layer in the chain), it struck me the other day how much of the chain I've actually had to touch: In my test setup, the signal comes into a Blackmagic Intensity Shuttle. At some point, I found what I believe is a bug in the card's firmware; I couldn't fix it, but a workaround was applied in the Linux kernel. (I also have some of their PCI cards, in which I haven't found any bugs, but I have found bugs in their drivers.) From there, it goes into bmusb, a driver I wrote myself. bmusb uses libusb-1.0 to drive the USB card from userspace but for performance and stability reasons, I patched libusb to use the new usbfs zerocopy support in the Linux kernel. (The patch is still pending review.) Said zerocopy support wasn't written by me, but I did the work to clean up the support and push it upstream (it's in the 4.6-rc* series). Once safely through bmusb, it goes of course into Nageru, which I wrote myself. Nageru uses Movit for pixel processing, which I also wrote myself. Movit in turn uses OpenGL; I've found bugs in all three major driver implementations, and fixed a Nageru-related one in Mesa (and in the process of debugging that, found bugs in apitrace, a most useful OpenGL debugger). Sound goes through zita-resampler to stretch it ever so gently (in case audio and video clocks are out of sync), which I didn't wrote, but patched to get SSE support (patch pending upstream). So now Nageru chews a bit on it, and then encodes the video using x264 (that's the new part in 1.3.0 of course, you need a fast CPU to do that as opposed to using Quick Sync). I didn't write x264, but I had to redo parts of the speedcontrol patch (not part of upstream; awaiting review semi-upstream) because of bugs and outdated timings, but I also found a bug in x264 proper (fixed by upstream, pending inclusion). Muxing is done through ffmpeg, where I actually found multiple bugs in the muxer (some of which are still pending fixes). Once the stream is safely encoded and hopefully reasonably standards-conforming (that took me quite a while), it goes to Cubemap, which I wrote, for reflection to clients. For low-bitrate clients, it takes a detour through VLC to get a re-encode on a faster machine to lower bitrate I've found multiple bugs in VLC's streaming support in the past (and also fixed some of them, plus written the code that interacts with Cubemap). From there it goes to any of several clients, usually a browser. I didn't write any browsers (thank goodness!), but I wrote the client-side JavaScript that picks the closest relay, and the code for sending it to a Chromecast. I also found a bug in Chrome for Android (will be fixed in version 50 or 51, although the fix was just about turning on something that was already in the works), and one in Firefox for Linux (fixed by patching GStreamer's MP4 demuxer, although they've since switched away from that to something less crappy). IE/Edge also broke at some point, but unfortunately I don't have a way to report bugs to Microsoft. There's also at least one VLC bug involved on the client side (it starts decoding frames too late if they come with certain irregular timestamps, which causes them to drop), but I want to verify that they still persist even after the muxer is fixed before I go deep on that. Moral of the story: If anyone wants to write a multimedia application and says I'll just use <framework, language or library XYZ>, and I'll get everything for free; I just need to click things together! , they simply don't know what they're talking about and are in for a rude awakening. Multimedia is hard, an amazing amount of things can go wrong, complex systems have subtle bugs, and there is no silver bullet.

Matthias Klumpp: A GNOME Software Hackfest report

Two weeks ago was the GNOME Software hackfest in London, and I ve been there! And I just now found the time to blog about it, but better do it late than never  . Arriving in London and finding the Red Hat offices After being stuck in trains for the weekend, but fortunately arriving at the airport in time, I finally made it to London with quite some delay due to the slow bus transfer from Stansted Airport. After finding the hotel, the next issue was to get food and a place which accepted my credit card, which was surprisingly hard in defence of London I must say though, that it was a Sunday, 7 p.m. and my card is somewhat special (in Canada, it managed to crash some card readers, so they needed a hard-reset). While searching for food, I also found the Red Hat offices where the hackfest was starting the next day by accident. My hotel, the office and the tower bridge were really close, which was awesome! I have been to London in 2008 the last time, and only for a day, so being that close to the city center was great. The hackfest didn t leave any time to visit the city much, but by being close to the center, one could hardly avoid the London experience  . Cool people working on great stuff towerbridge2016That s basically the summary for the hackfest  . It was awesome to meet with Richard Hughes again, since we haven t seen each other in person since 2011, but work on lots of stuff together. This was especially important, since we managed to solve quite some disagreements we had over stuff Richard even almost managed to make me give in to adding <kudos/> to the AppStream spec, something which I was pretty against supporting (it didn t make it yet, but I am no longer against the idea of having that the remaining issues are solvable). Meeting Iain Lane again (after FOSDEM) was also very nice, and also seeing other people I ve only worked with over IRC or bug reports (e.g. William, Kalev, ) was great. Also lots of new people were there, like guys from Endless, who build their low-budget computer for developing/emerging countries on top of GNOME and Linux technologies. It s pretty cool stuff they do, you should check out their website! (they also build their distribution on top of Debian, which is even more awesome, and something I didn t know before (because many Endless people I met before were associated with GNOME or Fedora, I kind of implicitly assumed the system was based on Fedora  )). The incarnation of GNOME Software used by endless looks pretty different from what the normal GNOME user sees, since it s adjusted for a different audience and input method. But it looks great, and is a good example for how versatile GS already is! And for upstream GNOME, we ve seen some pretty great mockups done by Endless too I hope those will make it into production somehow.
Ironically, a "snapstore" was close to the office ;-)

Ironically, a snapstore was close to the office ;-)

XdgApp and sandboxing of apps was also a big topic, aside from Ubuntu and Endless integration. Fortunately, Alexander Larsson was also there to answer all the sandboxing and XdgApp-questions. I used the time to follow up on a conversation with Alexander we started at FOSDEM this year, about the Limba vs. XdgApp bundling issue. While we are in-line on the sandboxing approach, the way how software is distributed is implemented differently in Limba and XdgApp, and it is bad to have too many bundling systems around (doesn t make for a good story where we can just tell developers ship as this bundling format, and it will be supported everywhere ). Talking with Alex about this was very nice, and I think there is a way out of the too-many-solutions dilemma, at least for Limba and XdgApp I will blog about that separately soon. On the Ubuntu side, a lot of bugs and issues were squashed and changes upstreamed to GNOME, and people were generally doing their best to reduce Richard s bus-factor on the project a little  . I mainly worked on AppStream issues, finishing up the last pieces of appstream-generator and running it against some sample package sets (and later that week against the whole Debian archive). I also started to implement support for showing AppStream issues in the Debian PTS (this work is not finished yet). I also managed to solve a few bugs in the old DEP-11 generator and prepare another release for Ubuntu. We also enjoyed some good Japanese food, and some incredibly great, but also suddenly very expensive Indian food (but that s a different story  ). The most important thing for me though was to get together with people actually using AppStream metadata in software centers and also more specialized places. This yielded some useful findings, e.g. that localized screenshots are not something weird, but actually a wanted feature of Endless for their curated AppStore. So localized screenshots will be part of the next AppStream spec. Also, there seems to be a general need to ship curation information for software centers somehow (which apps are featured? how are they styled? added special banners for some featured apps, app of the day features, etc.). This problem hasn t been solved, since it s highly implementation-specific, and AppStream should be distro-agnostic. But it is something we might be able to address in a generic way sooner or later (I need to talk to people at KDE and Elementary about it). In summary It was a great event! Going to conferences and hackfests always makes me feel like it moves projects leaps ahead, even if you do little coding. Sorting out issues together with people you see in person (rather than communicating with them via text messages or video chat), is IMHO always the most productive way to move forward (yeah, unless you do this every week, but I think you get my point  ). For me, being the only (and youngest ^^) developer at the hackfest who was not employed by any company in the FLOSS business, the hackfest was also motivating to continue to invest spare time into working on these projects. So, the only thing left to do is a huge shout out of THANK YOU to the Ubuntu Community Fund and therefore the Ubuntu community for sponsoring me! You rock! Also huge thanks to Canonical for organizing the sponsoring really quickly, so I didn t get into trouble with paying my flights.
Laney and attente walking on the Millennium Bridge after we walked the distance between Red Hat and Canonical's offices.

Laney and attente on the Millennium Bridge after we walked the distance between Red Hat and Canonical s offices.

To worried KDE people: No, I didn t leave the blue side I just generally work on cross-desktop stuff, and would like all desktops to work as well as possible

Dirk Eddelbuettel: RcppMgsPack 0.1.0

Over the last few months, I have been working casually on a new package to integrate MessagePack with R. What is MessagePack, you ask? To quote its website, "It's like JSON, but fast and small." Or in more extended terms:
MessagePack is an efficient binary serialization format. It lets you exchange data among multiple languages like JSON. But it's faster and smaller. Small integers are encoded into a single byte, and typical short strings require only one extra byte in addition to the strings themselves.
Now, serialization formats are a dime a dozen: JSON, BSON, Protocol Buffers, CaptnProto, Flatbuffer. The list goes on and on. So why another? In a nutshell: "software ecosystems". I happen to like working with Redis, and within the world of Redis, MessagePack is a first-class citizen supported by things close to the core like the embedded Lua interpreter, as well as fancy external add-ons such as the Redis Desktop Manager GUI. So nothing overly fundamentalist here, but a fairly pragmatic choice based on what happens to fit my needs. Plus, having worked on and off with Protocol Buffers for close to a decade, the chance of working with something not requiring a friggin' schema compiler seemed appealing for a chance. So far, we have been encoding a bunch of data streams at work via MessagePack into Redis (and of course back). It works really well---header-only C++11 libraries for the win. I'll provide an updated RcppRedis which uses this (if present) in due course. For now and the foreseeable future, this RcppMsgPack package will live only on the ghrr drat repository. To make RcppMsgPack work, I currently have to include the MessagePack 1.4.0 headers. A matching package for this version of the headers is in Debian but so far only in experimental. Once this hits the mainline repository I can depend on it, and upload a (lighter, smaller) RcppMsgPack to CRAN. Until then, please just do
## install drat if not present
if (!require(drat)) install.packages("drat")
## use drat to select ghrr repo
drat::addRepo("ghrr")
## install RcppMsgPack
install.packages("RcppMsgPack")
More details, issue tickets etc are at the GitHub repository.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

25 April 2016

Antoine Beaupr : My free software activities, April 2016

Debian Long Term Support (LTS) This is my 5th month working on Debian LTS, started by Raphael Hertzog at Freexian. This is my largest month so far, in which I worked on completing the Xen and NSS packages updates from last month, but also spent a significant amount of time working on phpMyAdmin and libidn.

Updates to NSS and Xen completed This basically consisted on following up on the reviews from other security people. I basically continued building up on Brian's work and tested the package on a test server at Koumbit, which seems to have survived well the upgrade. The details are in this post to the debian-lts mailing list. As for NSS, the package was mostly complete, but I forgot to ship the tests for some reason, so I added them back. I also wrote the release team to see if it was possible to update NSS to the same version in all suites. Unfortunately, this issue is still pending, but I still hope we can find better ways of managing that package in the long term.

IDN and phpMyAdmin Most of my time this month was spent working on IDN and phpMyAdmin. Unfortunately, it turns out that someone else had worked on the libidn package. This is partly my fault: I forgot to check in the dsa-needed.txt file for assignment before working on the package. But considering how in flux the workflow currently is with the switch between the main security team and the LTS team for the wheezy maintenance, I don't feel too bad. Still, I prepared a package which was a bit more painful than it should have been because of GNUlib. I didn't even know about GNUlib before, oddly enough, and after that experience, I feel that it should just not exist at all anymore. I have filed a bug to remove that dependency at the very least, but I do not clearly see how such a tool is necessary on Debian at this point in time. But phpMyAdmin, no one had worked on that. And I understand why: even though it's a very popular package, there were quite a few outstanding issues (8!) in Wheezy, with 10-15 patches to be ported. Plus, it's ... well, PHP. And old PHP at that, with parts of it with modern autoloader classes, and other with mixed HTML and PHP content, require (and not require_once) and all sorts of nasty things you still find in the PHP universe. I nevertheless managed to produce a new Debian package for wheezy and test it on Koumbit's test servers. Hopefully, that can land into Wheezy soon.

Long term software support I am a little worried that we are, both in Jessie and Wheezy sitting in between stable releases for phpMyAdmin, something that is a recurring issue for a lot of packages in Debian stable or LTS. Sometimes, it just happens that the version that happens to be in Debian testing when it is released as stable is just not a supported release upstream. It's the case for phpMyAdmin in Jessie (4.3, whereas 4.0 and 4.4 are supported) and Wheezy (3.4, although it's unclear how long that was supported upstream). But even if the next Debian stable (Stretch), would pick a stable release upstream, there is actually no phpMyAdmin release that has a support window as long as Debian stable (roughly 3 years), let alone as long as Debian LTS (5 years). This is a similar problem with NSS: upstream is simply not supporting their product in the long term, or at least not in the terms we are used to in the Debian community (ie. only security fixes or regressions). This is, in my opinion, a real concern for the reliability and sustainability of the computing infrastructure we are creating. While some developers are of the opinion that software older than 18 months is too old, here we are shipping hardware and software in space or we have Solaris, which is supported for 16 years! Now that is a serious commitment and something we can rely on. 18 months is really, really, a tiny short time in the history of our civilization. I know computer programmers and engineers like to think of themselves in elitist terms, that they are changing the world every other year. But the truth is that things have not changed much in the last 4 decades where computing has existed, both in terms of security or functionality. Two quotes from my little quotes collection come to mind here:
Software gets slower faster than hardware gets faster. - Wirth's law The future is already here it's just not very evenly distributed. - William Gibson
Because of course, the response to my claims that computing is not really advancing is "but look! we have supercomputers in our pockets now!" Yes, of course, we do have those fancy phones and they are super-connected, but they are a threat to our fundamental rights and freedom. And those glittering advances always pale in comparison to what could be done if we wouldn't be wasting our time rewriting the same software over and over again on different, often proprietary, platforms, simply because of the megalomaniac fantasies of egoistic programmers. It would be great to build something that lasts, for a while. Software that does not need to be updated every 16 months. You'd think that something as basic as a screensaver release could survive what is basically the range of human infancy. Yet it seems we like to run mindlessly in the minefield of software development, one generation following the other without questioning the underlying assumption of infinite growth that permeates our dying civilization. I have talked about this before of course, but working with the LTS project just unnerves me so bad that I just needed to let out another rant. (For the record, I really have a lot of respect for JWZ and all the work he has done in the free software world. I frequently refer to his "no-bullshit" backup guide and use Xscreensaver daily. But I do think he was wrong in this case: asking Debian to remove Xscreensaver is just too much. The response from the maintainer was exemplary of how to handle such issues in the future. I restarted Xscreensaver after the stable update, and the message is gone, and things are still all fine. Thanks JWZ and Tormod for keeping things rolling.)

Other free software work With that in mind, I obviously didn't stop doing other computing work this month. In fact, I did a lot of work to try to generally fix the internet, that endless and not-quite-gratifying hobby so many of us are destroying our bodies to accomplish.

Build tools I have experimented a bit more with different build tools. I got worried because at some point cowbuilder got orphaned and I figured I could refresh the way I build packages for LTS. I looked into sbuild, but that ended up not bringing much improvements over my current cowbuilder setup (which I really need to document better). I was asked by the new maintainer to open a bug report to make such setups easier by guessing the basepath better, so we'll see how that goes. I did enjoy the simplicity of gitpkg and discovered cowpoke which made it about 2 times faster to build packages because I could use another server to build larger packages. I also found that gitpkg doesn't use -n by default when calling gzip, which makes it harder to reproduce tarballs when they are themselves built reproducibly, which is the case for Github tarballs (really nice of them). So I filed bug #820842 about that. It would be pretty awesome if such buildds would be available for Debian Developers to do their daily tasks. It could simply be a machine that would spin up a chroot with cowbuilder or it could even be a full, temporary VM although that would take way more resources than a simple VM with a cowbuilder setup. In the meantime, I should probably look at whalebuilder as an alternative to cowbuilder. It is a tool that supports building packages within a Docker chroot, which means that packages are built from a clean environment like pbuilder, and using COW optimisations but also without privileges or network access, which is a huge plus especially when you build untrusted packages.

Ikiwiki admonitions I have done some work to implement Moinmoin-like admonitions in Ikiwiki, something I am quite happy about since it's something I was really missing about Moinmoin. Admonitions bring a really nice way to outline certain blocks with varying severity levels and distinct styles. For example:
Admonitions are great!
This was done with a macro, but basically, since Markdown allows more or less arbitrary HTML, this can also be done with the <div> tag. I like that we don't have a new weird markup here. Yet, I still liked the sub-parser feature of MoinMoin, something that can be implemented in Ikiwiki, but it's a little more clunky. Normally, you'd probably do this with the inline macro and subpages, but it's certainly less intuitive that directly inlined content.

Ereader I got a new e-reader! I was hesitant between the Kobo Aura H20 and the Kobo Glo HD, which were the ones available at Bestbuy. So I bought both and figured I would return the other. That was a painful decision! In the end, both machines are pretty nice:
  • Aura H2O
    • Pros:
      • waterproof
      • larger screen (makes it easier to see web pages and better for the eyes)
      • naturally drawn to it
    • Cons:
      • heavier
      • larger (fits in outside pocket though)
      • port cover finicky
      • more expensive (180$) - prices may go down in future
  • Aura Glo HD
    • Pros
      • smaller (fits in inside pocket of both coats)
      • better resolution in theory (can't notice in practice)
      • cheaper (100$)
      • may be less common on the future (larger models more common? just a guess)
    • Cons
      • no SD card
      • smaller screen
      • power button in the middle
... but in the end, I ended up settling down on the Glo, mostly for the price. Heck, I saved around 100$, so for that amount, I could have gotten two machines so that if one breaks I would still have the other. I have ordered a cover for it on Deal Extreme about two weeks ago, and it still hasn't arrived. I suspect it's going to take a few more months to get there, by which point I may have changed e-reader again. Note that both e-readers needed an update to calibre, so I started working on a calibre backport (#818309) which I will complete soon. So anyways, I looked into better ways of transferring articles from the web to the e-reader, something which I do quite a bit to avoid spending too much time on the computer. Since the bookmark manager I use (Bookie) is pretty much dead, I started looking at other alternatives. And partly inspired by Framasoft's choice of Wallabag for their bookmarking service (Framabag), I started to look into that software, especially since my friend who currently runs the Bookie instance is thinking of switching to Wallabag as well. It seems the simplest way to browse articles remotely through a standard protocol is by implementing OPDS support in Wallabag. OPDS is a standard developed in part by the Internet Archive and it allows for browsing book collections and downloading them. Articles and bookmarks would then be presented as individual books that would be accessible from any OPDS-compatible device. Unfortunately, the Kobo e-readers don't support OPDS out of the box: you need to setup some OPDS-compatible reader like Koreader. And that I found nearly impossible to do: I was able to setup KSM (the "start menu", not to be confused with that KSM), but not Koreader in KSM. Besides, I do not want a separate OS running here on the tablet: I just want to start Koreader every once in a while. KSM just starts another system when you reboot the e-reader, something which is not really convenient on the Kobo. Basically, I just want to add Koreader as a tile in the home screen on the e-reader. I found the documentation on that topic to be sparse and hard to follow. It is often dispersed across multiple forum threads and involves uploading random binaries, often proprietary, to the e-reader. It had been a long time since I was asked to "register my software" frenetically, and I hadn't missed that one bit. So I decided to stay away from this until that solution and its documentation matures a bit.

Streaming re-established I have worked a bit on my home radio stream. I simply turned the Liquidsoap stream back online, and did a few tweaks to the documentation that I had built back then. All that experimenting led me to do two NMUs. One was for gmpc-plugins to fix a FTBFS (bug #807735) and to properly kill the shout streamer when completing the playback (bug #820908). The other was to fix the ezstream manpage (bug #573928), a patch that had been sitting there for 5 years! This was to try to find an easy way to stream random audio (say from a microphone) to the Icecast server, something which is surprisingly difficult, consider how basic that functionality is. I was surprised to see that Darkice just completely fails to start (bug #821040) and I had to fallback to the simplest ices2 software to stream the audio. I am still having issues with Liquidsoap: it's really unstable! As a server, I would expect it to keep running for days if not years. Unfortunately, there's always something that makes it crash. I had assertion failed (bug #821112) and I keep seeing it crash after 2-3 days fairly reliably, a bug I reported 3 years ago and that is still not fixed (bug #727307). Switching back the stream to Vorbis (because I was having problems with the commandline mp3 players and ogg123 is much more lightweight) created another set of problems too, this time with the phone. It seems that Android cannot stream Vorbis at all, something that is even worse in Cyanogenmod... I also had to tweak my MPD config to make the Android client be able to load the larger playlists (see dmix buffer is full).

Android apps So I have also done quite a bit of work again on my phone. I finally was told how to access from Termux from adb shell which is pretty cool because now I can start a screen on my phone and then, when I'm tired of tapping to type, I can just reconnect to it when I plug in a USB cable on my laptop. I sent a pull request to fix the documentation regarding that. I also tried to see how my SMS and Signal situation could be improved. Right now, I have two different apps to do SMS on my phone: I use both Signal and the VoIP.ms SMS client, because I do not have a contract or SIM card in my phone. Both work well independently, but it's somewhat annoying to have to switch between the two. (In fact, I feel that Signal itself has an issue with how it depends on the network to send encrypted messages: I often have to "ping" people in clear text (and therefore in the other app) so that they connect to their data plan to fetch my "secure" signal messages...) Anyways, I figured it would be nice if at least there would be a SMS fallback in Signal that would allow me to send regular text messages from signal through Voip.MS. That was dismissed really fast. Moxie even closed the conversation completely, something I had never experienced before, and doesn't feel exactly pleasant. The Voip.MS side was of course not impressed and basically shrugged it off because Signal was not receptive. I also tried to clear up the Libresignal confusion: there are 3 different projects named "Libresignal", and I am not sure I figured out the right thing, even though the issue is now closed and there's a FAQ that is supposed to make all that clear. Nevertheless, I opened two distinct feature requests to try to steer the conversation into a more productive direction: GCM-less calls and GCM support. But I'm not sure neither will go anywhere. In the meantime, I am using the official signal client, which I downloaded using gplaycli and which I keep up to date with Aptoide. Even though the reliability of that site is definitely questionable, it seems that once you have a trusted version, it is safe to upgrade, regardless of the source because there is a trust path between you and the developer. I also filed a few issues with varying levels of success/response from the community:

Random background radiation And then there's of course the monthly background noise of all the projects I happened to not only stumble on, but also file bugs or patches against:

Gunnar Wolf: Passover / Pesaj, a secular viewpoint, a different viewpoint... And slowly becoming history!

As many of you know (where "you" is "people reading this who actually know who I am), I come from a secular Jewish family. Although we have some religious (even very religious) relatives, neither my parents nor my grandparents were religious ever. Not that spirituality wasn't important to them My grandparents both went deep into understanding by and for themselves the different spiritual issues that came to their mind, and that's one of the traits I most remember about them while I was growing up. But formal, organized religion was never much welcome in the family; again, each of us had their own ways to concile our needs and fears with what we thought, read and understood. This week is the Jewish celebration of Passover, or Pesaj as we call it (for which Passover is a direct translation, as Pesaj refers to the act of the angel of death passing over the houses of the sons of Israel during the tenth plague in Egypt; in Spanish, the name would be Pascua, which rather refers to the ritual sacrifice of a lamb that was done in the days of the great temple)... Anyway, I like giving context to what I write, but it always takes me off the main topic I want to share. Back to my family. I am a third-generation member of the Hashomer Hatzair zionist socialist youth movement; my grandmother was among the early Hashomer Hatzair members in Poland in the 1920s, both my parents were active in the Mexico ken in the 1950s-1960s (in fact, they met and first interacted there), and I was a member from 1984 until 1996. It was also thanks to Hashomer that my wife and I met, and if my children get to have any kind of Jewish contact in their lifes, I hope it will be through Hashomer as well. Hashomer is a secular, nationalist movement. A youth movement with over a century of history might seem like a contradiction. Over the years, of course, it has changed many details, but as far as I know, the essence is still there, and I hope it will continue to be so for good: Helping shape integral people, with identification with Judaism as a nation and not as a religion; keeping our cultural traits, but interpreting them liberally, and aligned with a view towards the common good Socialism, no matter how the concept seems pass nowadays. Colectivism. Inclusion. Peaceful coexistence with our neighbours. Acceptance of the different. I could write pages on how I learnt about each of them during my years in Hashomer, how such concepts striked me as completely different as what the broader Jewish community I grew up in understood and related to them... But again, I am steering off the topic I want to pursue. Every year, we used to have a third Seder (that is, a third Passover ceremony) at Hashomer. A third one, because as tradition mandates two ceremonies to be held outside Israel, and a movement comprised of people aged between 7 and 21, having a seder competing with the familiar one would not be too successful, we held a celebration on a following day. But it would never be the same as the "formal" Pesaj: For the Seder, the Jewish tradition mandates following the Hagada The Seder always follows a predetermined order (literally, Seder means order), and the Hagad (which means both legend and a story that is spoken; you can find full Hagadot online if you want to see what rites are followed; I found a seemingly well done, modern, Hebrew and English version, a more traditional one, in Hebrew and Spanish, and Wikipedia has a description including its parts and rites) is, quite understandably, full with religious words, praises for God, and... Well, many things that are not in line with Hashomer's values. How could we be a secular movement and have a big celebration full with praises for God? How could we yearn for life in the kibbutz distance from the true agricultural meaning of the celebration? The members of Hashomer Hatzair repeatedly took on the task (or, as many would see it, the heresy) of adapting the Hagada to follow their worldview, updated it for the twentieth century, had it more palatable for our peculiarities. Yesterday, when we had our Seder, I saw my father still has together with the other, more traditional Hagadot we use two copies of the Hagad he used at Hashomer Hatzair's third Seder. And they are not only beautiful works showing what they, as very young activists thought and made solemn, but over time, they are becoming historic items by themselves (one when my parents were still young janijim, in 1956, and one when they were starting to have responsabilities and were non-formal teachers or path-showers, madrijim, in 1959). He also had a copy of the Hagad we used in the 1980s when I was at Hashomer; this last one was (sadly?) not done by us as members of Hashomer, but prepared by a larger group between Hashomer Hatzair and the Mexican friends of Israeli's associated left wing party, Mapam. This last one, I don't know which year it was prepared and published on, but I remember following it in our ceremony. So, I asked him to borrow me the three little books, almost leaflets, and scanned them to be put online. Of course, there is no formal licensing information in them, much less explicit authorship information, but they are meant to be shared So I took the liberty of uploading them to the Internet Archive, tagging them as CC-0 licensed. And if you are interested in them, flowing over and back between Spanish and Hebrew, with many beautiful texts adapted for them from various sources, illustrated by our own with the usual heroic, socialist-inspired style, and lovingly hand-reproduced using the adequate technology for their day... Here they are: I really enjoyed the time I took scanning and forming them, reading some passages, imagining ourselves and my parents as youngsters, remembering the beautiful work we did at such a great organization. I hope this brings this joy to others like it did to me. , . Once shomer, always shomer.

Norbert Preining: G del and Daemons an excursion into literature

Explaining G del s theorems to students is a pain. Period. How can those poor creatures crank their mind around a Completeness and an Incompleteness Proof I understand that. But then, there are brave souls using G del s theorems to explain the world of demons to writers, in particular to answer the question:
You can control a Demon by knowing its True Name, but why?
goedel-glabrezu Very impressive. Found at worldbuilding.stackexchange.com, pointed to me by a good friend. I dare to full quote author Cort Ammon (nothing more is known), to preserve this masterpiece. Thanks!!!!
Use of their name forces them to be aware of the one truth they can never know. Tl/Dr: If demons seek permanent power but trust no one, they put themselves in a strange position where mathematical truisms paint them into a corner which leaves their soul small and frail holding all the strings. Use of their name suggests you might know how to tug at those strings and unravel them wholesale, from the inside out! Being a demon is tough work. If you think facing down a 4000lb Glabrezu without their name is difficult, try keeping that much muscle in shape in the gym! Never mind how many manicurists you go through keeping the claws in shape! I don t know how creative such demons truly are, but the easy route towards the perfect French tip that can withstand the rigors of going to the gym and benching ten thousand pounds is magic. Such a demon might learn a manicure spell from the nearby resident succubi. However, such spells are often temporary. No demon worth their salt is going to admit in front of a hero that they need a moment to refresh their mani before they can fight. The hero would just laugh at them. No, if a demon is going to do something, they re going to do it right, and permanently. Not just nice french tips with a clear lacquer over the top, but razor sharp claws that resharpen themselves if they are blunted and can extend or retract at will! In fact, come to think of it, why even go to the gym to maintain one s physique? Why not just cast a magic spell which permanently makes you into the glorious Hanz (or Franz) that the trainer keeps telling you is inside you, just waiting to break free. Just get the spell right once, and think of the savings you could have on gym memberships. Demons that wish to become more powerful, permanently, must be careful. If fairy tales have anything to teach is, it s that one of the most dangerous things you can do is wish for something forever, and have it granted. Forever is a very long time, and every spell has its price. The demon is going to have to make sure the price is not greater than the perks. It would be a real waste to have a manicure spell create the perfect claws, only to find that they come with a peculiar perchance to curve towards one s own heart in an attempt to free themselves from the demon that cast them. So we need proofs. We need proofs that each spell is a good idea, before we cast it. Then, once we cast it, we need proof that the spell actually worked intended. Otherwise, who knows if the next spell will layer on top perfectly or not. Mathematics to the rescue! The world of First Order Logic (FOL, or herefter simply logic ) is designed to offer these guarantees. With a few strokes of a pen, pencil, or even brush, it can write down a set of symbols which prove, without a shadow of a doubt, that not only will the spell work as intended, but that the side effects are manageable. How? So long as the demon can prove that they can cast a negation spell to undo their previous spell, the permanency can be reverted by the demon. With a few more fancy symbols, the demon can also prove that nobody else outside of the demon can undo their permanency. It s a simple thing for mathematics really. Mathematics has an amazing spell called reductio ad infinitum which does unbelievable things. However, there is a catch. There is always a catch with magic, even when that magic is being done through mathematics. In 1931, Kurt G del published his Incompleteness Theorems. These are 3 fascinating works of mathematical art which invoke the true names of First Order Logic and Set Theory. G del was able to prove that any system which is powerful enough to prove out all of algebra (1 + 1 = 2, 2 + 1 = 3, 3 * 5 = 15, etc.), could not prove its own validity. The self referential nature of proving itself crossed a line that First Order Logic simply could not return from. He proved that any system which tries must pick up one of these five traits: If the demon wants itself to be able to cancel the spell, his proof is going to have to include his own abilities, creating just the kind of self referential effects needed to invoke G del s incompleteness theorems. After a few thousand years, the demon may realize that this is folly. A fascinating solution the demon might choose is to explore the incomplete solution to G del s challenge. What if the demon permits the spell to change itself slightly, but in an unpredictable way. If the demon was a harddrive, perhaps he lets a single byte get changed by the spell in a way he cannot expect. This is actually enough to sidestep G del s work, by introducing incompleteness. However, now we have to deal with pesky laws of physic and magics. We can t just create something out of nothing, so if we re going to let the spell change a single byte of us, there must be a single byte of information, its dual, that is unleashed into the world. Trying to break such conservation laws opens up a whole can of worms. Better to let that little bit go free into the world. Well, almost. If you repeat this process a whole bunch of times, layering spells like a Matryoska doll, you re eventually left with a soul that is nothing but the leftover bits of your spells that you simply don t know enough about to use. If someone were collecting those bits and pieces, they might have the undoing of your entire self. You can t prove it, of course, but its possible that those pieces that you sent out into the world have the keys to undo your many layers of armor, and then you know they are the bits that can nullify your soul if they get there. So what do you do? You hide them. You cast your spells only on the darkest of nights, deep in a cave where no one can see you. If you need assistants, you make sure to ritualistically slaughter them all, lest one of them know your secret and whisper it to a bundle of reeds, The king has horns, if you are familiar with the old fairy tale. Make it as hard as possible for the secret to escape, and hope that it withers away to nothingness before someone discovers it, leaving you invincible. Now we come back to the name. The demon is going to have a name it uses to describe its whole self, including all of the layers of spellcraft it has acquired. This will be a great name like Abraxis, the Unbegotten Father or Satan, lord of the underworld. However, they also need to keep track of their smaller self, their soul. Failure to keep track of this might leave them open to an attack if they had missed a detail when casting their spells, and someone uncovered something to destroy them. This would be their true name, potentially something less pompous, like Gaylord Focker or Slartybartfarst. They would never use this name in company. Why draw attention to the only part of them that has the potential to be weak. So when the hero calls out for Slartybartfarst, the demon truly must pay attention. If they know the name the demon has given over the remains of their tattered soul, might they know how to undo the demon entirely? Fear would grip their inner self, like a child, having to once again consider that they might be mortal. Surely they would wish to destroy the hero that spoke the name, but any attempt runs the risk of falling into a trap and exposing a weakness (surely their mind is racing, trying to enumerate all possible weaknesses they have). It is surely better for them to play along with you, once you use their true name, until they understand you well enough to confidently destroy you without destroying themselves. So you ask for answers which are plausible. This one needs no magic at all. None of the rules are invalid in our world today. Granted finding a spell of perfect manicures might be difficult (believe me, some women have spent their whole life searching), but the rules are simply those of math. We can see this math in non-demonic parts of society as well. Consider encryption. An AES-256 key is so hard to brute force that it is currently believed it is impossible to break it without consuming 3/4 of the energy in the Milky Way Galaxy (no joke!). However, know the key, and decryption is easy. Worse, early implementations of AES took shortcuts. They actually left the signature of the path they took through the encryption in their accesses to memory. The caches on the CPU were like the reeds from the old fable. Merely observing how long it took to read data was sufficient to gather those reeds, make a flute, and play a song that unveils the encryption key (which is clearly either The king has horns or 1-2-3-4-5 depending on how secure you think your luggage combination is). Observing the true inner self of the AES encryption implementations was enough to completely dismantle them. Of course, not every implementation fell victim to this. You had to know the name of the implementation to determine which vulnerabilities it had, and how to strike at them. Or, more literally, consider the work of Alfred Whitehead, Principia Mathematica. Principia Mathematica was to be a proof that you could prove all of the truths in arithmetic using purely procedural means. In Principia Mathematica, there was no manipulation based on semantics, everything he did was based on syntax manipulating the actual symbols on the paper. G del s Incompleteness Theorem caught Principia Mathematica by the tail, proving that its own rules were sufficient to demonstrate that it could never accomplish its goals. Principia Mathematica went down as the greatest Tower of Babel of modern mathematical history. Whitehead is no longer remembered for his mathematical work. He actually left the field of mathematics shortly afterwards, and became a philosopher and peace advocate, making a new name for himself there. (by Cort Ammon)

24 April 2016

Dirk Eddelbuettel: Brad Mehldau at the CSO, again

Almost seven years since the last time we saw him here, Brad Mehldau returned to the CSO for a concert on Friday eve in his standard trio setup with Larry Grenadier on bass and Jeff Ballard on drums. The material mostly (all?) new and drawn from the upcoming album Blues and Ballads. The morning of the concert---which happened to be the final one in their tour---he retweeted a bit from this review in the Boston Globe
[Brad Mehldau] flashed facets of his renowned pianism: crystalline touch, deep lyricism, harmonic sophistication, adroit use of space, and the otherworldly independence of his right and left hands.
I cannot really describe his style any better than this. If you get a chance to see him, go!

21 April 2016

Mario Lang: Scraping the web with Python and XQuery

During a JAWS for Windows training, I was introduced to the Research It feature of that screen reader. Research It is a quick way to utilize web scraping to make working with complex web pages easier. It is about extracting specific information from a website that does not offer an API. For instance, look up a word in an online dictionary, or quickly check the status of a delivery. Strictly speaking, this feature does not belong in a screen reader, but it is a very helpful tool to have at your fingertips. Research It uses XQuery (actually, XQilla) to do all the heavy lifting. This also means that the Research It Rulesets are theoretically also useable on other platforms. I was immediately hooked, because I always had a love for XPath. Looking at XQuery code is totally self-explanatory for me. I just like the syntax and semantics. So I immediately checked out XQilla on Debian, and found #821329 and #821330, which were promptly fixed by Tommi Vainikainen, thanks to him for the really quick response! Unfortunately, making xqilla:parse-html available and upgrading to the latest upstream version is not enough to use XQilla on Linux with the typical webpages out there. Xerces-C++, which is what XQilla uses to fetch web resources, does not support HTTPS URLs at the moment. I filed #821380 to ask for HTTPS support in Xerces-C to be enabled by default. And even with HTTPS support enabled in Xerces-C, the xqilla:parse-html function (which is based on HTML Tidy) fails for a lot of real-world webpages I tried. Manually upgrading the six year old version of HTML Tidy in Debian to the latest from GitHub (tidy-html5, #810951) did not help a lot either.
Python to the rescue XQuery is still a very nice language for extracting information from markup documents. XQilla just has a bit of a hard time dealing with the typical HTML documents out there. After all, it was designed to deal with well-formed XML documents. So I decided to build myself a little wrapper around XQilla which fetches the web resources with the Python Requests package, and cleans the HTML document with BeautifulSoup (which uses lxml to do HTML parsing). The output of BeautifulSoup can apparently be passed to XQilla as the context document. This is a fairly crazy hack, but it works quite reliably so far. Here is how one of my web scraping rules looks like:
from click import argument, group
@group()
def xq():
  """Web scraping for command-line users."""
  pass
@xq.group('github.com')
def github():
  """Quick access to github.com."""
  pass
@github.command('code_search')
@argument('language')
@argument('query')
def github_code_search(language, query):
  """Search for source code."""
  scrape(get='https://github.com/search',
         params= 'l': language, 'q': query, 'type': 'code' )
The function scrape automatically determines the XQuery filename according to the callers function name. Here is how github_code_search.xq looks like:
declare function local:source-lines($table as node()*) as xs:string*
 
  for $tr in $table/tr return normalize-space(data($tr))
 ;
let $results := html//div[@id="code_search_results"]/div[@class="code-list"]
for $div in $results/div
let $repo := data($div/p/a[1])
let $file := data($div/p/a[2])
let $link := resolve-uri(data($div/p/a[2]/@href))
return (concat($repo, ": ", $file), $link, local:source-lines($div//table),
        "---------------------------------------------------------------")
That is all I need to implement a custom web scraping rule. A few lines of Python to specify how and where to fetch the website from. And a XQuery file that specifies how to mangle the document content. And thanks to the Python click package, the various entry points of my web scraping script can easily be called from the command-line. Here is a sample invokation:
fx:~/xq% ./xq.py github.com
Usage: xq.py github.com [OPTIONS] COMMAND [ARGS]...
  Quick access to github.com.
Options:
  --help  Show this message and exit.
Commands:
  code_search  Search for source code.
fx:~/xq% ./xq.py github.com code_search Pascal '"debian/rules"'
prof7bit/LazPackager: frmlazpackageroptionsdeb.pas
https://github.com/prof7bit/LazPackager/blob/cc3e35e9bae0c5a582b0b301dcbb38047fba2ad9/frmlazpackageroptionsdeb.pas
230 procedure TFDebianOptions.BtnPreviewRulesClick(Sender: TObject);
231 begin
232 ShowPreview('debian/rules', EdRules.Text);
233 end;
234
235 procedure TFDebianOptions.BtnPreviewChangelogClick(Sender: TObject);
---------------------------------------------------------------
prof7bit/LazPackager: lazpackagerdebian.pas
https://github.com/prof7bit/LazPackager/blob/cc3e35e9bae0c5a582b0b301dcbb38047fba2ad9/lazpackagerdebian.pas
205 + 'mv ../rules debian/' + LF
206 + 'chmod +x debian/rules' + LF
207 + 'mv ../changelog debian/' + LF
208 + 'mv ../copyright debian/' + LF
---------------------------------------------------------------
For the impatient, here is the implementation of scrape:
from bs4 import BeautifulSoup
from bs4.element import Doctype, ResultSet
from inspect import currentframe
from itertools import chain
from os import path
from os.path import abspath, dirname
from subprocess import PIPE, run
from tempfile import NamedTemporaryFile
import requests
def scrape(get=None, post=None, find_all=None,
           xquery_name=None, xquery_vars= , **kwargs):
  """Execute a XQuery file.
  When either get or post is specified, fetch the resource and run it through
  BeautifulSoup, passing it as context to the XQuery.
  If find_all is given, wrap the result of executing find_all on
  the BeautifulSoup in an artificial HTML body.
  If xquery_name is not specified, the callers function name is used.
  xquery_name combined with extension ".xq" is searched in the directory
  where this Python script resides and executed with XQilla.
  kwargs are passed to get or post calls.  Typical extra keywords would be:
  params -- To pass extra parameters to the URL.
  data -- For HTTP POST.
  """
  response = None
  url = None
  context = None
  if get is not None:
    response = requests.get(get, **kwargs)
  elif post is not None:
    response = requests.post(post, **kwargs)
  if response is not None:
    response.raise_for_status()
    context = BeautifulSoup(response.text, 'lxml')
    dtd = next(context.descendants)
    if type(dtd) is Doctype:
      dtd.extract()
    if find_all is not None:
      context = context.find_all(find_all)
    url = response.url
  if xquery_name is None:
    xquery_name = currentframe().f_back.f_code.co_name
  cmd = ['xqilla']
  if context is not None:
    if type(context) is BeautifulSoup:
      soup = context
      context = NamedTemporaryFile(mode='w')
      print(soup, file=context)
      cmd.extend(['-i', context.name])
    elif isinstance(context, list) or isinstance(context, ResultSet):
      tags = context
      context = NamedTemporaryFile(mode='w')
      print('<html><body>', file=context)
      for item in tags: print(item, file=context)
      print('</body></html>', file=context)
      context.flush()
      cmd.extend(['-i', context.name])
  cmd.extend(chain.from_iterable(['-v', k, v] for k, v in xquery_vars.items()))
  if url is not None:
    cmd.extend(['-b', url])
  cmd.append(abspath(path.join(dirname(__file__), xquery_name + ".xq")))
  output = run(cmd, stdout=PIPE).stdout.decode('utf-8')
  if type(context) is NamedTemporaryFile: context.close()
  print(output, end='')
The full source for xq can be found on GitHub. The project is just two days old, so I have only implemented three scraping rules as of now. However, adding new rules has been made deliberately easy, so that I can just write up a few lines of code whenever I find something on the web which I'd like to scrape on the command-line. If you find this "framework" useful, make sure to share your insights with me. And if you impelement your own scraping rules for a public service, consider sharing that as well. If you have an comments or questions, send me mail. Oh, and by the way, I am now also on Twitter as @blindbird23.

20 April 2016

Ben Hutchings: Experiments with signed kernels and modules in Debian

I've lately been working on support for Secure Boot in Debian, mostly in the packages maintained by the kernel team. My instructions for setting up UEFI Secure Boot are based on OVMF running on KVM/QEMU. All 'Designed for Windows' PCs should allow reconfiguration of SB, but it may not be easy to do so. They also assume that the firmware includes an EFI shell. Updated: Robert Edmonds pointed out that the 'Designed for Windows' requirements changed with Windows 10: The ability to reconfigure SB is indeed now optional for devices which are designed to always boot with a specific Secure Boot configuration. I also noticed that the requirements say that OEMs should not sign an EFI shell binary. Therefore I've revised the instructions to use efibootmgr instead. Background UEFI Secure Boot, when configured and enabled (which it is on most new PCs) requires that whatever it loads is signed with a trusted key. The one common trusted key for PCs is held by Microsoft, and while they will sign other people's code for a nominal fee, they require that it also validates the code it loads, i.e. the kernel or next stage boot loader. The kernel in turn is responsible for validating any code that could compromise its integrity (kernel modules, kexec images). Currently there are no such signed boot loaders in Debian, though the shim and grub-signed packages included in many other distributions should be usable. However it's possible to load an appropriately configured Linux kernel directly from the UEFI firmware (typically through the shell) which is what I'm doing at the moment. Packaging signed kernels Signing keys obviously need to be protected against disclosure; the private keys can't be included in a source package. We also won't install them on buildds separately, and generating signatures at build time would of course be unreproducible. So I've created a new source package, linux-signed, which contains detached signatures prepared offline. Currently the binary packages built from linux-signed also contain only detached signatures, which are applied as necessary at installation time. The signed kernel image (only on x86 for now) is named /boot/vmlinuz-kversion.efi.signed. However, since packages must not modify files owned by another package and I didn't want to dpkg-divert thousands of modules, the module signatures remain detached. Detached module signatures are a new invention of mine, and require changes in kmod and various other packages to support them. (An alternate might be to put signed modules under a different directory and drop a configuration file in /lib/depmod.d to make them higher priority. But then we end up with two copies of every module installed, which can be a substantial waste of space.) Preparation The packages you need to repeat the experiment: For Secure Boot, you'll then need to copy the signed kernel and the initrd onto the EFI system partition, normally mounted at /boot/efi. SB requires a Platform Key (PK) which will already be installed on a real PC. You can replace it but you don't need to. If you're using OVMF, there are no persistent keys so you do need to generate your own:
openssl req -new -x509 -newkey rsa:2048 -keyout pk.key -out pk.crt \
    -outform der -nodes
You'll also need to install the certificate for my kernel image signing key, which is under debian/certs in the linux-signed package. OVMF requires this in DER format:
openssl x509 -in linux-signed-1~exp3/debian/certs/linux-image-benh@debian.org.cert.pem \
    -out linux.crt -outform der 
You'll need to copy the certificate(s) to a FAT-formatted partition such as the EFI system partition, so that the firmware can read it. Use efibootmgr to add a boot entry for the kernel, for example:
efibootmgr -c -d /dev/sda -L linux-signed -l '\vmlinuz.efi' -u 'initrd=initrd.img root=/dev/sda2 ro quiet'
You should use the same kernel parameters as usual, except that you also need to specify the initrd filename using the initrd= parameter. The EFI stub code at the beginning of the kernel will load the initrd using EFI boot services. Enabling Secure Boot
  1. Reboot the system and enter UEFI setup
  2. Find the menu entry for Secure Boot customisation (in OVMF, it's under 'Device Manager' for some reason)
  3. In OVMF, enrol the PK from pk.crt
  4. Add linux.crt to the DB (whitelist database)
  5. Ensure that Secure Boot is enabled and in 'User Mode'
Booting the kernel in Secure Boot If all went well, Linux will boot as normal. You can confirm that Secure Boot was enabled by reading /sys/kernel/security/securelevel, which will contain 1 if it was. Module signature validation Module signatures are now always checked and unsigned modules will be given the 'E' taint flag. If Secure Boot is used or you add the kernel parameter module.sig_enforce=1, unsigned modules will be rejected. You can also turn on signature enforcement and turn off various other methods of modifying kernel code (such as kexec) by writing 1 to /sys/kernel/security/securelevel.

Reproducible builds folks: Reproducible builds: week 51 in Stretch cycle

What happened in the reproducible builds effort between April 10th and April 16th 2016: Toolchain fixes Antoine Beaupr suggested that gitpkg stops recording timestamps when creating upstream archives. Antoine Beaupr also pointed out that git-buildpackage diverges from the default gzip settings which is a problem for reproducibly recreating released tarballs which were made using the defaults. Alexis Bienven e submitted a patch extending sphinx SOURCE_DATE_EPOCH support to copyright year. Packages fixed The following packages have become reproducible due to changes in their build dependencies: atinject-jsr330, avis, brailleutils, charactermanaj, classycle, commons-io, commons-javaflow, commons-jci, gap-radiroot, jebl2, jetty, libcommons-el-java, libcommons-jxpath-java, libjackson-json-java, libjogl2-java, libmicroba-java, libproxool-java, libregexp-java, mobile-atlas-creator, octave-econometrics, octave-linear-algebra, octave-odepkg, octave-optiminterp, rapidsvn, remotetea, ruby-rinku, tachyon, xhtmlrenderer. The following packages became reproducible after getting fixed: Some uploads fixed some reproducibility issues, but not all of them: Patches submitted which have not made their way to the archive yet: diffoscope development Zbigniew J drzejewski-Szmek noted in #820631 that diffoscope doesn't work properly when a file contains several cpio archives. Package reviews 21 reviews have been added, 14 updated and 22 removed in this week. New issue found: timestamps_in_htm_by_gap. Chris Lamb reported 10 new FTBFS issues. Misc. The video and the slides from the talk "Reproducible builds ecosystem" at LibrePlanet 2016 have been published now. This week's edition was written by Lunar and Holger Levsen. h01ger automated the maintenance and publishing of this weekly newsletter via git.

Norbert Preining: GnuPG notes: subkeys, yubikey, gpg1 vs gpg2

Switching from one GnuPG master key to the usage of subkeys was long on my list of things I wanted to do, but never came around. With the advent of a YubiKey NEO in my pocket I finally took the plunge: reading through lots of web pages (and adding one here for confusion), trying to understand the procedures, and above all, understanding my own requirements! gpg-subkeys-yubi To sum up a long story, it was worth the plunge, and all over the security level of my working environment has improved considerable. While the advantages of subkeys are well documented (e.g., Debian Wiki), at the end of the day I was like probably many Debian Developers having one master key that was used for every action: mail decryption and signing, signing of uploads, etc. Traveling a lot I always felt uncomfortable. Despite a lengthy passphrase, I still didn t want my master key to get into wrong hands in case the laptop got stolen. Furthermore, I had my master key on several computers (work, laptop, mail server), which didn t help a lot either. With all this, I started to compile a list of requirements/objectives I wanted to have: Warning Before we start a word of caution make backups, best is to make backups at every stage. You don t want that an erroneous operations wipes out your precious keys without a backup! Preparation In the following I will assume that MASTERKEY environment variable contains the id of the master key to be converted. Furthermore, I have followed some of the advice here, so key ids will be shown in long format. Let us start with the current situation:
$ gpg -K $MASTERKEY
sec   4096R/0x6CACA448860CDC13 2010-09-14
      Key fingerprint = F7D8 A928 26E3 16A1 9FA0  ACF0 6CAC A448 860C DC13
uid                            Norbert Preining <norbert@preining.info>
uid                            Norbert Preining <preining@logic.at>
uid                            Norbert Preining <preining@debian.org>
uid                            Norbert Preining <preining@jaist.ac.jp>
ssb   4096R/0xD1D2BD14810F62B3 2010-09-14
In the following we will go through the following steps: Yubikey SmartCard setup There are several guides out there, but I will in very near future write one about using the NEO for various usage scenaria including GPG keys. Edit the current key The following can be done in one session or in different sessions, the screen logs are after starting with:
$ gpg --expert --edit-key $MASTERKEY
add expiry date Having an expiry date on your key serves two purposes: If you loose it, it will solve itself automatically, and furthermore, you are forced to deal with the key and refresh your gpg knowledge at least once a year. That are two perfect reasons to set expiry to one year. The following log selects each key in turn and sets its expiry date.
$ gpg --expert --edit-key $MASTERKEY
gpg (GnuPG) 1.4.20; Copyright (C) 2015 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
 
Secret key is available.
 
pub  4096R/0x6CACA448860CDC13  created: 2010-09-14  expires: never       usage: SC  
                               trust: ultimate      validity: ultimate
sub  4096R/0xD1D2BD14810F62B3  created: 2010-09-14  expires: never       usage: E   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
 
gpg> expire
Changing expiration time for the primary key.
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 1y
Key expires at Mon 06 Feb 2017 08:09:16 PM JST
Is this correct? (y/N) y
 
You need a passphrase to unlock the secret key for
user: "Norbert Preining <norbert@preining.info>"
4096-bit RSA key, ID 0x6CACA448860CDC13, created 2010-09-14
 
Enter passphrase:
 
pub  4096R/0x6CACA448860CDC13  created: 2010-09-14  expires: 2017-02-06  usage: SC  
                               trust: ultimate      validity: ultimate
sub  4096R/0xD1D2BD14810F62B3  created: 2010-09-14  expires: never       usage: E   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
 
gpg> key 1
 
pub  4096R/0x6CACA448860CDC13  created: 2010-09-14  expires: 2017-02-06  usage: SC  
                               trust: ultimate      validity: ultimate
sub* 4096R/0xD1D2BD14810F62B3  created: 2010-09-14  expires: never       usage: E   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
 
gpg> expire
Changing expiration time for a subkey.
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 1y
Key expires at Mon 06 Feb 2017 08:09:27 PM JST
Is this correct? (y/N) y
 
You need a passphrase to unlock the secret key for
user: "Norbert Preining <norbert@preining.info>"
4096-bit RSA key, ID 0x6CACA448860CDC13, created 2010-09-14
 
Enter passphrase:
 
pub  4096R/0x6CACA448860CDC13  created: 2010-09-14  expires: 2017-02-06  usage: SC  
                               trust: ultimate      validity: ultimate
sub* 4096R/0xD1D2BD14810F62B3  created: 2010-09-14  expires: 2017-02-06  usage: E   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
Add a photo Not strictly necessary, but an interesting feature. gpg suggests 240 288, I resized a photo of my head, greyscaled it, and optimized it with jpegoptim -s -m40 my-photo.jpg. The parameter 40 is the quality, I played around a bit to find the best balance between size and quality. The size should not be too big as the photo will be part of the key!
gpg> addphoto
 
Pick an image to use for your photo ID.  The image must be a JPEG file.
Remember that the image is stored within your public key.  If you use a
very large picture, your key will become very large as well!
Keeping the image close to 240x288 is a good size to use.
 
Enter JPEG filename for photo ID: GPG/norbert-head.jpg
Is this photo correct (y/N/q)? y
 
You need a passphrase to unlock the secret key for
user: "Norbert Preining <norbert@preining.info>"
4096-bit RSA key, ID 0x6CACA448860CDC13, created 2010-09-14
 
Enter passphrase:
 
pub  4096R/0x6CACA448860CDC13  created: 2010-09-14  expires: 2017-02-06  usage: SC  
                               trust: ultimate      validity: ultimate
sub* 4096R/0xD1D2BD14810F62B3  created: 2010-09-14  expires: 2017-02-06  usage: E   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ unknown] (5)  [jpeg image of size 4185]
Add subkeys of 2048bit for signing/encryption/authentication Now comes the interesting part, adding three subkeys: one for signing, one for encrypting, and one for authentication. The one for signing is the one you will use for signing your uploads to Debian as well as emails. The authentication key will later be used to provide ssh authentication. Note that you have to use the --expert expert option to edit-key (as shown above), otherwise gpg does not allow to do this. As I want to move the subkeys to the Yubikey NEO, a keysize of 2048bits is necessary. First for the signing:
gpg> addkey
Key is protected.
 
You need a passphrase to unlock the secret key for
user: "Norbert Preining <norbert@preining.info>"
4096-bit RSA key, ID 0x6CACA448860CDC13, created 2010-09-14
 
Enter passphrase:
 
Please select what kind of key you want:
   (3) DSA (sign only)
   (4) RSA (sign only)
   (5) Elgamal (encrypt only)
   (6) RSA (encrypt only)
   (7) DSA (set your own capabilities)
   (8) RSA (set your own capabilities)
Your selection? 4
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 
Requested keysize is 2048 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 1y
Key expires at Mon 06 Feb 2017 08:10:06 PM JST
Is this correct? (y/N) y
Really create? (y/N) y
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
....+++++
..........+++++
 
pub  4096R/0x6CACA448860CDC13  created: 2010-09-14  expires: 2017-02-06  usage: SC  
                               trust: ultimate      validity: ultimate
sub* 4096R/0xD1D2BD14810F62B3  created: 2010-09-14  expires: 2017-02-06  usage: E   
sub  2048R/0xEC00B8DAD32266AA  created: 2016-02-07  expires: 2017-02-06  usage: S   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ unknown] (5)  [jpeg image of size 4185]
Now the same for encryption key:
gpg> addkey
Key is protected.
 
You need a passphrase to unlock the secret key for
user: "Norbert Preining <norbert@preining.info>"
4096-bit RSA key, ID 0x6CACA448860CDC13, created 2010-09-14
 
Enter passphrase:
 
Please select what kind of key you want:
   (3) DSA (sign only)
   (4) RSA (sign only)
   (5) Elgamal (encrypt only)
   (6) RSA (encrypt only)
   (7) DSA (set your own capabilities)
   (8) RSA (set your own capabilities)
Your selection? 6
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 
Requested keysize is 2048 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 1y
Key expires at Mon 06 Feb 2017 08:10:20 PM JST
Is this correct? (y/N) y
Really create? (y/N) y
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
..+++++
........+++++
 
pub  4096R/0x6CACA448860CDC13  created: 2010-09-14  expires: 2017-02-06  usage: SC  
                               trust: ultimate      validity: ultimate
sub* 4096R/0xD1D2BD14810F62B3  created: 2010-09-14  expires: 2017-02-06  usage: E   
sub  2048R/0xEC00B8DAD32266AA  created: 2016-02-07  expires: 2017-02-06  usage: S   
sub  2048R/0xBF361ED434425B4C  created: 2016-02-07  expires: 2017-02-06  usage: E   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ unknown] (5)  [jpeg image of size 4185]
Finally for the authentication key. Note that only here the --expert is necessary! We use (8) RSA (set your own capabilities) and then toggle sign and encryption capabilities off, and authentication on.
gpg> addkey
Key is protected.
 
You need a passphrase to unlock the secret key for
user: "Norbert Preining <norbert@preining.info>"
4096-bit RSA key, ID 0x6CACA448860CDC13, created 2010-09-14
 
Enter passphrase:
 
Please select what kind of key you want:
   (3) DSA (sign only)
   (4) RSA (sign only)
   (5) Elgamal (encrypt only)
   (6) RSA (encrypt only)
   (7) DSA (set your own capabilities)
   (8) RSA (set your own capabilities)
Your selection? 8
 
Possible actions for a RSA key: Sign Encrypt Authenticate 
Current allowed actions: Sign Encrypt 
 
   (S) Toggle the sign capability
   (E) Toggle the encrypt capability
   (A) Toggle the authenticate capability
   (Q) Finished
 
Your selection? s
 
Possible actions for a RSA key: Sign Encrypt Authenticate 
Current allowed actions: Encrypt 
 
   (S) Toggle the sign capability
   (E) Toggle the encrypt capability
   (A) Toggle the authenticate capability
   (Q) Finished
 
Your selection? e
 
Possible actions for a RSA key: Sign Encrypt Authenticate 
Current allowed actions: 
 
   (S) Toggle the sign capability
   (E) Toggle the encrypt capability
   (A) Toggle the authenticate capability
   (Q) Finished
 
Your selection? a
 
Possible actions for a RSA key: Sign Encrypt Authenticate 
Current allowed actions: Authenticate 
 
   (S) Toggle the sign capability
   (E) Toggle the encrypt capability
   (A) Toggle the authenticate capability
   (Q) Finished
 
Your selection? q
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 
Requested keysize is 2048 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 1y
Key expires at Mon 06 Feb 2017 08:10:34 PM JST
Is this correct? (y/N) y
Really create? (y/N) y
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
......+++++
+++++
 
pub  4096R/0x6CACA448860CDC13  created: 2010-09-14  expires: 2017-02-06  usage: SC  
                               trust: ultimate      validity: ultimate
sub* 4096R/0xD1D2BD14810F62B3  created: 2010-09-14  expires: 2017-02-06  usage: E   
sub  2048R/0xEC00B8DAD32266AA  created: 2016-02-07  expires: 2017-02-06  usage: S   
sub  2048R/0xBF361ED434425B4C  created: 2016-02-07  expires: 2017-02-06  usage: E   
sub  2048R/0x9C7CA4E294F04D49  created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ unknown] (5)  [jpeg image of size 4185]
 
gpg> save
Check the current status Good point to take a break and inspect the current status. We should have one main key and three subkeys, all with expiry dates of 1 year ahead, and a photo also attached to the key:
$ gpg --expert --edit-key $MASTERKEY
gpg (GnuPG) 1.4.20; Copyright (C) 2015 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
 
Secret key is available.
 
gpg: checking the trustdb
gpg: public key 0x0FC3EC02FBBB8AB1 is 58138 seconds newer than the signature
gpg: 3 marginal(s) needed, 1 complete(s) needed, classic trust model
gpg: depth: 0  valid:   2  signed:  28  trust: 0-, 0q, 0n, 0m, 0f, 2u
gpg: depth: 1  valid:  28  signed:  41  trust: 28-, 0q, 0n, 0m, 0f, 0u
gpg: next trustdb check due at 2016-11-02
pub  4096R/0x6CACA448860CDC13  created: 2010-09-14  expires: 2017-02-06  usage: SC  
                               trust: ultimate      validity: ultimate
sub  4096R/0xD1D2BD14810F62B3  created: 2010-09-14  expires: 2017-02-06  usage: E   
sub  2048R/0xEC00B8DAD32266AA  created: 2016-02-07  expires: 2017-02-06  usage: S   
sub  2048R/0xBF361ED434425B4C  created: 2016-02-07  expires: 2017-02-06  usage: E   
sub  2048R/0x9C7CA4E294F04D49  created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg>
Create revocation certificate In case something happens, like all your backups are burned, your computers are destroyed, or all data stolen by the NSA, it is a good idea to have an old fashioned paper print out of a revocation certificate which allows you to revoke the key even if you are not in possession of it. This should be printed out and kept in a safe place.
$ gpg --gen-revoke $MASTERKEY > GPG/revoke-certificate-$MASTERKEY.txt
 
sec  4096R/0x6CACA448860CDC13 2010-09-14 Norbert Preining <norbert@preining.info>
 
Create a revocation certificate for this key? (y/N) y
Please select the reason for the revocation:
  0 = No reason specified
  1 = Key has been compromised
  2 = Key is superseded
  3 = Key is no longer used
  Q = Cancel
(Probably you want to select 1 here)
Your decision? 1
Enter an optional description; end it with an empty line:
> 
Reason for revocation: Key has been compromised
(No description given)
Is this okay? (y/N) y
 
You need a passphrase to unlock the secret key for
user: "Norbert Preining <norbert@preining.info>"
4096-bit RSA key, ID 0x6CACA448860CDC13, created 2010-09-14
 
Enter passphrase:
 
ASCII armored output forced.
Revocation certificate created.
Please move it to a medium which you can hide away; if the NSA or KGB or Mossad gets access to this certificate, they can use it to make your key unusable. It is smart to print this certificate and store it away, just in case your media become unreadable. Create gpg 2.1 structure There are currently three versions of gpg available: classic (version 1) which is one static binary, perfect for servers or scripting tasks; stable (version 2.0) which is the modularized version supporting OpenPGP, S/MIME, and Secure Shell; and finally modern (version 2.1 and up) with enhanced features like support for Elliptic Curve cryptography. Debian currently ships version 1 as standard, and also the modern version (but there are traces in experimental of a pending transition). The newer versions of GnuPG are modularized and use an agent. For the following we need to kill any running instance of gpg-agent.
$ killall gpg-agent
After that a simple call to gpg2 to list the secret keys will convert the layout to the new standard:
$ gpg2 -K $MASTERKEY
gpg: keyserver option 'ca-cert-file' is obsolete; please use 'hkp-cacert' in dirmngr.conf
gpg: starting migration from earlier GnuPG versions
gpg: porting secret keys from '/home/norbert/.gnupg/secring.gpg' to gpg-agent
gpg: key 0xD2BF4AA309C5B094: secret key imported
gpg: key 0x6CACA448860CDC13: secret key imported
gpg: migration succeeded
sec   rsa4096/0x6CACA448860CDC13 2010-09-14 [SC] [expires: 2017-02-06]
      Key fingerprint = F7D8 A928 26E3 16A1 9FA0  ACF0 6CAC A448 860C DC13
uid                   [ultimate] Norbert Preining <norbert@preining.info>
uid                   [ultimate] Norbert Preining <preining@logic.at>
uid                   [ultimate] Norbert Preining <preining@debian.org>
uid                   [ultimate] Norbert Preining <preining@jaist.ac.jp>
uid                   [ultimate] [jpeg image of size 4185]
ssb   rsa4096/0xD1D2BD14810F62B3 2010-09-14 [E] [expires: 2017-02-06]
ssb   rsa2048/0xEC00B8DAD32266AA 2016-02-07 [S] [expires: 2017-02-06]
ssb   rsa2048/0xBF361ED434425B4C 2016-02-07 [E] [expires: 2017-02-06]
ssb   rsa2048/0x9C7CA4E294F04D49 2016-02-07 [A] [expires: 2017-02-06]
After this there will be new files/directories in the .gnupg directory, in particular: .gnupg/private-keys-v1.d/ which contains the private keys. Creating backup Now your .gnupg directory contains still all the keys, available for gpg1 and gpg2.1. You MUST MAKE A BACKUP NOW!!! on at least 3 USB sticks and maybe some other offline media. Keep them in a safe place, better in different and safe places, you will need them for extending the expiry date, signing other keys, etc. Warning concerning USB and vfat file systems gpg >= 2.1 requires gpg-agent which in turn needs a socket. If you have the backup on an USB drive (most often with vfat file system), you need to redirect the socket, as vfat does not support sockets! Edit /USBSTICK/gnupghome/S.gpg-agent and enter there
%Assuan%
socket=/dev/shm/S.gpg-agent
After that the socket will be created in /dev/shm/ instead and invoking gpg with gpg2 --homedir /USBSTICK/gnupghome will work. You have done your backups, right? Move sub keys to card As I mentioned, I want to have no keys on my laptop which I carry around to strange countries, instead I want to have them all on a Yubikey NEO. I will describe the setup and usage in details soon, but mention here only how to move the keys to the card. This requires a finished setup including change of pins. Note that when using gpg2 to move the keys to the card, the local copies are actually deleted, but only for the gpg2(.1) files. The gpg1 secret keys are still all in place.
$ gpg2 --edit-key $MASTERKEY
gpg (GnuPG) 2.1.11; Copyright (C) 2016 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
 
Secret key is available.
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb  rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb  rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb  rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> key 2
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb* rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb  rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb  rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> keytocard
Please select where to store the key:
   (1) Signature key
   (3) Authentication key
Your selection? 1
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb* rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb  rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb  rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> key 2
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb  rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb  rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb  rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> key 3
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb  rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb* rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb  rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> keytocard
Please select where to store the key:
   (2) Encryption key
Your selection? 2
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb  rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb* rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb  rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> key 3
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb  rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb  rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb  rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> key 4
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb  rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb  rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb* rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> keytocard
Please select where to store the key:
   (3) Authentication key
Your selection? 3
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb  rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb  rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb* rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> key 4
 
sec  rsa4096/0x6CACA448860CDC13
     created: 2010-09-14  expires: 2017-02-06  usage: SC  
     trust: ultimate      validity: ultimate
ssb  rsa4096/0xD1D2BD14810F62B3
     created: 2010-09-14  expires: 2017-02-06  usage: E   
ssb  rsa2048/0xEC00B8DAD32266AA
     created: 2016-02-07  expires: 2017-02-06  usage: S   
ssb  rsa2048/0xBF361ED434425B4C
     created: 2016-02-07  expires: 2017-02-06  usage: E   
ssb  rsa2048/0x9C7CA4E294F04D49
     created: 2016-02-07  expires: 2017-02-06  usage: A   
[ultimate] (1). Norbert Preining <norbert@preining.info>
[ultimate] (2)  Norbert Preining <preining@logic.at>
[ultimate] (3)  Norbert Preining <preining@debian.org>
[ultimate] (4)  Norbert Preining <preining@jaist.ac.jp>
[ultimate] (5)  [jpeg image of size 4185]
 
gpg> save
Note the repetition of selecting and deselecting keys. Current status After this procedure we are now in the following situation: In gpg words it looks like this:
$ gpg2 -K $MASTERKEY
gpg: keyserver option 'ca-cert-file' is obsolete; please use 'hkp-cacert' in dirmngr.conf
sec   rsa4096/0x6CACA448860CDC13 2010-09-14 [SC] [expires: 2017-02-06]
      Key fingerprint = F7D8 A928 26E3 16A1 9FA0  ACF0 6CAC A448 860C DC13
uid                   [ultimate] Norbert Preining <norbert@preining.info>
uid                   [ultimate] Norbert Preining <preining@logic.at>
uid                   [ultimate] Norbert Preining <preining@debian.org>
uid                   [ultimate] Norbert Preining <preining@jaist.ac.jp>
uid                   [ultimate] [jpeg image of size 4185]
ssb   rsa4096/0xD1D2BD14810F62B3 2010-09-14 [E] [expires: 2017-02-06]
ssb>  rsa2048/0xEC00B8DAD32266AA 2016-02-07 [S] [expires: 2017-02-06]
ssb>  rsa2048/0xBF361ED434425B4C 2016-02-07 [E] [expires: 2017-02-06]
ssb>  rsa2048/0x9C7CA4E294F04D49 2016-02-07 [A] [expires: 2017-02-06]
 
$ gpg -K $MASTERKEY
sec   4096R/0x6CACA448860CDC13 2010-09-14 [expires: 2017-02-06]
      Key fingerprint = F7D8 A928 26E3 16A1 9FA0  ACF0 6CAC A448 860C DC13
uid                            Norbert Preining <norbert@preining.info>
uid                            Norbert Preining <preining@logic.at>
uid                            Norbert Preining <preining@debian.org>
uid                            Norbert Preining <preining@jaist.ac.jp>
uid                            [jpeg image of size 4185]
ssb   4096R/0xD1D2BD14810F62B3 2010-09-14 [expires: 2017-02-06]
ssb   2048R/0xEC00B8DAD32266AA 2016-02-07 [expires: 2017-02-06]
ssb   2048R/0xBF361ED434425B4C 2016-02-07 [expires: 2017-02-06]
ssb   2048R/0x9C7CA4E294F04D49 2016-02-07 [expires: 2017-02-06]
 
$ gpg2 --card-status
 
....
Name of cardholder: Norbert Preining
....
PIN retry counter : 3 3 3
Signature counter : 0
Signature key ....: 5871 F824 2DCC 3660 2362  BE7D EC00 B8DA D322 66AA
      created ....: 2016-02-07 11:10:06
Encryption key....: 2501 195C 90AB F4D2 3DEA  A303 BF36 1ED4 3442 5B4C
      created ....: 2016-02-07 11:10:20
Authentication key: 9CFB 3775 C164 0E99 F0C8  014C 9C7C A4E2 94F0 4D49
      created ....: 2016-02-07 11:10:34
General key info..: sub  rsa2048/0xEC00B8DAD32266AA 2016-02-07 Norbert Preining <norbert@preining.info>
sec   rsa4096/0x6CACA448860CDC13  created: 2010-09-14  expires: 2017-02-06
ssb   rsa4096/0xD1D2BD14810F62B3  created: 2010-09-14  expires: 2017-02-06
ssb>  rsa2048/0xEC00B8DAD32266AA  created: 2016-02-07  expires: 2017-02-06
                                  card-no: 0006 03645719
ssb>  rsa2048/0xBF361ED434425B4C  created: 2016-02-07  expires: 2017-02-06
                                  card-no: 0006 03645719
ssb>  rsa2048/0x9C7CA4E294F04D49  created: 2016-02-07  expires: 2017-02-06
                                  card-no: 0006 03645719
$
Remove private master keys You are sure that you have a working backup? Did you try it with gpg --homedir ...? Only if you are really sure, continue. We are now removing the master key from both the gpg2 and gpg1 setup. removal for gpg2 gpg2 keeps the private keys in ~/.gnupg/private-keys-v1.d/KEYGRIP.key and the KEYGRIP can be found by adding --with-keygrip to the key listing. Be sure to delete the correct file, the one related to the master key.
$ gpg2 --with-keygrip --list-key $MASTERKEY
pub   rsa4096/0x6CACA448860CDC13 2010-09-14 [SC] [expires: 2017-02-06]
      Key fingerprint = F7D8 A928 26E3 16A1 9FA0  ACF0 6CAC A448 860C DC13
      Keygrip = 9DC1E90703856C1DE0EAC970CED7ABF5EE5EF79D
uid                   [ultimate] Norbert Preining <norbert@preining.info>
uid                   [ultimate] Norbert Preining <preining@logic.at>
uid                   [ultimate] Norbert Preining <preining@debian.org>
uid                   [ultimate] Norbert Preining <preining@jaist.ac.jp>
uid                   [ultimate] [jpeg image of size 4185]
sub   rsa4096/0xD1D2BD14810F62B3 2010-09-14 [E] [expires: 2017-02-06]
      Keygrip = 4B8FF57434DD989243666377376903281D861596
sub   rsa2048/0xEC00B8DAD32266AA 2016-02-07 [S] [expires: 2017-02-06]
      Keygrip = 39B14EF1392F2F251863A87AE4D44CE502755C39
sub   rsa2048/0xBF361ED434425B4C 2016-02-07 [E] [expires: 2017-02-06]
      Keygrip = E41C8DDB2A22976AE0DA8D7D11F586EA793203EA
sub   rsa2048/0x9C7CA4E294F04D49 2016-02-07 [A] [expires: 2017-02-06]
      Keygrip = A337DE390143074C6DBFEA64224359B9859B02FC
 
$ rm ~/.gnupg/private-keys-v1.d/9DC1E90703856C1DE0EAC970CED7ABF5EE5EF79D.key
$
After that the missing key is shown in gpg2 -K with an additional # meaning that the key is not available:
$ gpg2 -K $MASTERKEY
sec#  rsa4096/0x6CACA448860CDC13 2010-09-14 [SC] [expires: 2017-02-06]
...
removal for gpg1 Up to gpg v2.0 there is no simple way to delete only one part of the key. We export the subkeys, delete the private key, and reimport the subkeys:
$ gpg --output secret-subkeys --export-secret-subkeys $MASTERKEY
 
$ gpg --delete-secret-keys $MASTERKEY
 
sec  4096R/0x6CACA448860CDC13 2010-09-14 Norbert Preining <norbert@preining.info>
 
Delete this key from the keyring? (y/N) y
This is a secret key! - really delete? (y/N) y
 
$ gpg --import secret-subkeys
gpg: key 0x6CACA448860CDC13: secret key imported
gpg: key 0x6CACA448860CDC13: "Norbert Preining <norbert@preining.info>" not changed
gpg: Total number processed: 1
gpg:              unchanged: 1
gpg:       secret keys read: 1
gpg:   secret keys imported: 1
 
$
Current status We are basically at the stage we wanted to achieve: For gpg2.1 only the old encryption key is available, the master key is not, and the other sub keys are moved to the yubikey:
$ gpg2 -K $MASTERKEY
sec#  rsa4096/0x6CACA448860CDC13 2010-09-14 [SC] [expires: 2017-02-06]
      Key fingerprint = F7D8 A928 26E3 16A1 9FA0  ACF0 6CAC A448 860C DC13
uid                   [ultimate] Norbert Preining <norbert@preining.info>
uid                   [ultimate] Norbert Preining <preining@logic.at>
uid                   [ultimate] Norbert Preining <preining@debian.org>
uid                   [ultimate] Norbert Preining <preining@jaist.ac.jp>
uid                   [ultimate] [jpeg image of size 4185]
ssb   rsa4096/0xD1D2BD14810F62B3 2010-09-14 [E] [expires: 2017-02-06]
ssb>  rsa2048/0xEC00B8DAD32266AA 2016-02-07 [S] [expires: 2017-02-06]
ssb>  rsa2048/0xBF361ED434425B4C 2016-02-07 [E] [expires: 2017-02-06]
ssb>  rsa2048/0x9C7CA4E294F04D49 2016-02-07 [A] [expires: 2017-02-06]
$
And for gpg <= 2.0 the old encryption key and the sub keys are available, but the master key is not:
$ gpg -K $MASTERKEY
sec#  4096R/0x6CACA448860CDC13 2010-09-14 [expires: 2017-02-06]
      Key fingerprint = F7D8 A928 26E3 16A1 9FA0  ACF0 6CAC A448 860C DC13
uid                            Norbert Preining <norbert@preining.info>
uid                            Norbert Preining <preining@logic.at>
uid                            Norbert Preining <preining@debian.org>
uid                            Norbert Preining <preining@jaist.ac.jp>
uid                            [jpeg image of size 4185]
ssb   4096R/0xD1D2BD14810F62B3 2010-09-14 [expires: 2017-02-06]
ssb   2048R/0xEC00B8DAD32266AA 2016-02-07 [expires: 2017-02-06]
ssb   2048R/0xBF361ED434425B4C 2016-02-07 [expires: 2017-02-06]
ssb   2048R/0x9C7CA4E294F04D49 2016-02-07 [expires: 2017-02-06]
 
$
Split the .gnupg directory for mail server and laptop As mentioned, I want to have a gpg1 version available at the server where I read my emails, and be able to sign/encrypt emails there, while on my laptop no secret key is available. Thus I prepare two gnupg directories. For the mailserver the gpg2 specific files are removed:
$ cp -a .gnupg .gnupg-mail
$ cd .gnupg-mail
$ rm -rf private-keys-v1.d/ pubring.gpg~ reader_0.status
$ rm -rf S.gpg-agent* S.scdaemon .gpg-v21-migrated
On my laptop, where I did all this operation, I remove the gpg1 files, namely the outdated secring.gpg:
$ cd $HOME/.gnupg
$ rm secring.gpg
As a last step I move the .gnupg-mail directory to my mail server. Once could *expire* the old encryption key, but for now I leave it as is. Upload keys to keyservers If you are a Debian Developer, a simple update of your master key will suffice:
gpg --keyserver hkp://keyring.debian.org --send-key YOURMASTERKEYID
Note that the update from the keyring server to the actual Debian keyring takes up to one month. Until that time either do not upload anything, or use the (offline) master key for signing. After your key has been updated in the Debian keyring, signatures made with the signing subkey will be accepted for uploading to Debian. It might be also a good idea to upload your new keys to some keyservers like:
gpg --keyserver hkp://pool.sks-keyservers.net --send-key $MASTERKEY
Now you an also fix the configuration file skew between gpg1 and gpg2. Further remark I am currently trying to use the authentication key from my Yubikey NEO as ssh key, but bugs (see #795368 and #818969) prohibit it at the moment. Raphael Herzog gave a possible fix by killing the gpg-agent and restarting it with gpg-agent --daemon from an X terminal, and I can confirm that this worked. After one year before the key expires I need to extend the key validity for another year. For this you need the offline master key. I will describe the process when it becomes necessary. Reading list The following web sites have been useful in collecting the necessary information:
  1. https://iain.learmonth.me/yubikey-neo-gpg/
  2. https://iain.learmonth.me/yubikey-udev/
  3. http://blog.josefsson.org/2014/06/23/offline-gnupg-master-key-and-subkeys-on-yubikey-neo-smartcard/
  4. https://wiki.debian.org/Subkeys
  5. https://jclement.ca/articles/2015/gpg-smartcard/ as modernized version of (3)
  6. https://www.esev.com/blog/post/2015-01-pgp-ssh-key-on-yubikey-neo/ similar style, with ssh and gnome-keyring infos
  7. http://karlgrz.com/2fa-gpg-ssh-keys-with-pass-and-yubikey-neo/ also good reading
  8. https://help.riseup.net/en/security/message-security/openpgp/best-practices good and concise advise on gpg practices
My writing is mostly based on (5) with additions from (4). Please let me know of any errors, improvements, and fixes. I hope this walk-through might help others in the same situation.

19 April 2016

Dariusz Dwornikowski: HAProxy and 503 HTTP errors with AWS ELB as a backend

Although, AWS provides load balancer service in the form of Elastic Load Balancer (ELB), a common trick is to use HAProxy in the middle to provide SSL offloading, complex routing and better logging.
In this scenario, a public ELB is the frontier of all the traffic, HAProxy farm in the middle is managed by an Auto Scaling Group, and one (or more) internal backend ELBs stay in front of Web farm. haproxy I think that HAProxy does not need any introductions here. It is highly scalable and reliable piece of software. There is however a small caveat when you use it with domain names and not IP addresses. To speed up things, HAProxy resolves all the domain named during startup (during config file parsing in fact). Hence, when the IP of a domain changes, you end up with a lot of 503s (Service Unavailable). Why is this important ? In AWS, ELB's IP can change over time, so it is recommended to use ELB's domain name. Now, when you use this domain name in HAProxy's backend, you can end up with 503s. ELB IPs do not change so often but still you would not want any downtimes. The solution is to configure runtime resolvers in HAProxy and use them in the backend (unforntunatelly this works only in HAProxy 1.6):
 ::haproxy
 resolvers myresolver
      nameserver dns1 10.10.10.10:53
      resolve_retries       30
      timeout retry         1s
      hold valid           10s
  backend mybackend
      server myelb-internal.123456.eu-west-1.elb.amazonaws.com check resolvers myresolver
Now HAProxy will check the domain at runtime, no more 503s.

Norbert Preining: Gaming: Monument Valley

With a small baby invading your lifestyle, not much time for other activities is left over, especially for gaming. Most of the times even using my computer is a one-hand-action. In these times mobile games that can be played one-handed are greatly appreciated. And if it is one like Monument Valley, full of atmosphere and incredibly stimulating game play, then the level of gratitude is near infinite. monument-valley1 Set in an Escherian universe where space and distance is often an illusion, the player is guiding a small princess through several levels (10+1 in the basic game, 8 more in the In-App-Purchase) of astonishing simplicity and beauty at the same time. Carefully crafted graphics, atmospheric music, calm game play (no action, don t worry), and the lovely crows sitting around and craaaahing at the little princess. My favorite level was the first of the expansion pack Forgotten shores called The Chasm a wonderful homage to the Lord of the Rings and the descent to the Bridge of Khazad-d m. Not one of the difficult levels, but definitely one of the most funny. The middle image in the above collage is from that level. I guess my only complain about this game is that it doesn t last long. I remember only one really difficult level where I had to play around quite some time. Most of the others are quite straight forward, but despite of that, you cannot stop playing until you are all through it. Simply a wonderful game, that was well worth every Yen. Thanks to the developers for doing innovative things in a perfect setting. monument-valley2 Post scriptum: After finishing this game I also tried Evo Explores, a clone of Monument Valley. The difference cannot be more stunning: Evo Explores is mostly repetitive, with a focus on an irrelevant story, simple graphics, and riddles that miss the ingenuity of the original.

18 April 2016

Dariusz Dwornikowski: XWiki and slashes in URI

XWiki is a great open source Atlassian Confluence replacement (some argue it is better, I leave it to your assessment). We use XWiki a lot at Tenesys to document internal projects, and create documentation of clients' platforms. We run XWiki in Tomcat application server, behind nginx proxy. We use great XWiki's plugin, called FAQ, which can be used to create, well FAQs. The problem we had was that sometimes people (me especially) created FAQ entries with a / in the name, which resulted in XWiki creating a slug with / character, which is used to delimit page hierarchy in XWIki. Basically, you wanted to write How to install Debian/Ubuntu package and you ended up with two pages: How to install Debian and a subpage Ubuntu package. You can't easily delete the 'slashed' FAQ page because by default the last one is deleted only. The solution to this problems is twofold. First of all, you need to tell Tomcat to allow passing encoded slash (%2F) oto XWiki. Add to -Dorg.apache.tomcat.util.buf.UDecoder.ALLOW_ENCODED_SLASH=true to CATALINA_OPTS. You can either do it via catalina.sh or catalina.opts. Second of all, you need to make sure that your nginx proxy directive is bare, i.e. does not contain URI part, see relevant stack question here. Basically you want your proxy_pass to look like that:
location /  
  proxy_pass http://backend;
 
... not like that.
location /  
  proxy_pass http://backend/xwiki;
 
I spent quite a lot of time before I discovered that nginx caveat. Hope it helps somebody too.

Dirk Eddelbuettel: RcppCCTZ 0.0.4

A few days ago a new upstream version "2.0" of CCTZ was released. See here for the corresponding post on the Google OpenSource Blog. CCTZ is a C++ library for translating between absolute and civil times using the rules of a time zone. It requires only a proper C++11 compiler and the standard IANA time zone data base which standard Unix, Linux, OS X, ... computers tend to have in /usr/share/zoneinfo. RcppCCTZ connects this library to R by relying on Rcpp. This new version adds more support to the notion of civil time representation -- i.e. independent of timezones -- which can then be mapped to different time zone representations. Changes in this version are summarized here:
Changes in version 0.0.4 (2016-04-17)
  • Synchronized with CCTZ v2 upstream.
  • Updated examples.cpp accordingly
A quick example is provided here where we look at the time when Neil Armstrong first stepped on the moon as an absolute ("civil") time and two local representations:
// from examples/hello.cc
// 
// [[Rcpp::export]]
int helloMoon()  
    cctz::time_zone syd;
    if (!cctz::load_time_zone("Australia/Sydney", &syd)) return -1;
    // Neil Armstrong first walks on the moon
    const auto tp1 = cctz::convert(cctz::civil_second(1969, 7, 21, 12, 56, 0), syd);
    const std::string s = cctz::format("%F %T %z", tp1, syd);
    Rcpp::Rcout << s << "\n";
    cctz::time_zone nyc;
    cctz::load_time_zone("America/New_York", &nyc);
    const auto tp2 = cctz::convert(cctz::civil_second(1969, 7, 20, 22, 56, 0), nyc);
    return tp2 == tp1 ? 0 : 1;
 
We can call this from R, and get the expected result (of equivalence between the dates):
R> library(RcppCCTZ)
R> helloMoon()
1969-07-21 12:56:00 +1000
[1] 0
R>
We also have a diff to the previous version thanks to CRANberries. More details, issue tickets etc at the GitHub repository.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

15 April 2016

Rapha&#235;l Hertzog: Freexian s report about Debian Long Term Support, March 2016

A Debian LTS logoLike each month, here comes a report about the work of paid contributors to Debian LTS. Individual reports In February, 111.75 work hours have been dispatched among 10 paid contributors. Their reports are available: Evolution of the situation The number of sponsored hours started to increase for April (116.75 hours, thanks to Sonus Networks) and should increase even further for May (with a new Gold sponsor currently joining us, Babiel GmbH). Hopefully the trend will continue so that we can reach our objective of funding the equivalent of a full-time position. At the end of the month the LTS team will be fully responsible of all Debian 7 Wheezy updates. For now paid contributors are still helping the security team by fixing packages that were fixed in squeeze already but that are still outstanding in wheezy. They are also looking for ways to ensure that some of the most complicated packages can be supported over the wheezy LTS timeframe. It is likely that we will seek external help (possibly from credativ which is already handling support of PostgreSQL) for the maintenance of Xen and that some other packages (like libav, vlc, maybe qemu?) will be upgraded to newer versions which are still maintained (either upstream or in Debian Jessie by the Debian maintainers). Thanks to our sponsors New sponsors are in bold.

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12 April 2016

Reproducible builds folks: Reproducible builds: week 48 in Stretch cycle

What happened in the reproducible builds effort between March 20th and March 26th: Toolchain fixes Daniel Kahn Gillmor worked on removing build path from build symbols submitting a patch adding -fdebug-prefix-map to clang to match GCC, another patch against gcc-5 to backport the removal of -fdebug-prefix-map from DW_AT_producer, and finally by proposing the addition of a normalizedebugpath to the reproducible feature set of dpkg-buildflags that would use -fdebug-prefix-map to replace the current directory with . using -fdebug-prefix-map. Sergey Poznyakoff merged the --clamp-mtime option so that it will be featured in the next Tar release. This option is likely to be used by dpkg-deb to implement deterministic mtimes for packaged files. Packages fixed The following packages have become reproducible due to changes in their build dependencies: augeas, gmtkbabel, ktikz, octave-control, octave-general, octave-image, octave-ltfat, octave-miscellaneous, octave-mpi, octave-nurbs, octave-octcdf, octave-sockets, octave-strings, openlayers, python-structlog, signond. The following packages became reproducible after getting fixed: Some uploads fixed some reproducibility issues, but not all of them: Patches submitted which have not made their way to the archive yet: tests.reproducible-builds.org i386 build nodes have been setup by converting 2 of the 4 amd64 nodes to i386. (h01ger) Package reviews 92 reviews have been removed, 66 added and 31 updated in the previous week. New issues: timestamps_generated_by_xbean_spring, timestamps_generated_by_mangosdk_spiprocessor. Chris Lamb filed 7 FTBFS bugs. Misc. On March 20th, Chris Lamb gave a talk at FOSSASIA 2016 in Singapore. The very same day, but a few timezones apart, h01ger did a presentation at LibrePlanet 2016 in Cambridge, Massachusetts. Seven GSoC/Outreachy applications were made by potential interns to work on various aspects of the reproducible builds effort. On top of interacting with several applicants, prospective mentors gathered to review the applications.

11 April 2016

Chris Lamb: Parsing Jenkins log output to determine job status

I recently made the same mistake a number of times when adding new hosts to my Ansible configuration and decided to ensure it couldn't happen again. The specifics of this particular issue were that whilst I had added the hostname to inventory file, I had neglected to add the host to the relevant group in my playbook:
oldhost
newhost
[mygroup]
oldhost
# missing newhost here
ansible-playbook would output no hosts matched but crucially return with an successful exit code. My continuous integration system (Jenkins) would infer that the task was successful and not notify me that anything was wrong:
$ ansible-playbook deploy-mygroup.yml --limit-hosts=newhost
<snip>
PLAY [deploy] *************************************************
skipping: no hosts matched
PLAY RECAP ****************************************************
[ERROR]: No plays were matched by any host.
$ echo $?
0

This seemed to violate a few principles to me (at the very least due of the "loud" use of ERROR without the corresponding return code) so I filed a pull request against Ansible that added an optional --error-if-no-plays-matched switch:
$ ansible-playbook [..] --error-if-no-plays-matched
<snip>
[ERROR]: No plays were matched by any host.
$ echo $?
1
In the end, upstream decided to pass on it as it could be implemented via a plugin system and desiring an immediate and potentially more-general solution I briefly looked into parsing the ansible-playbook output before moving onto parsing the Jenkins log itself. This turned out to be straightforward; using the Text-Finder plugin, I configured my Jenkins job to simply error if the log contained the string skipping: no hosts matched: https://lamby-www.s3.amazonaws.com/yadt/blog.Image/image/original/26.jpeg I am using the Job DSL plugin so that my configuration is backed onto revision control (highly recommended) so I actually used its textFinder publisher rather than the interface above:
publishers  
  textFinder(/^skipping: no hosts matched$/, '', true, false, false)
 

This results in the job "correctly" failing and alerting me:
+ ansible-playbook deploy-mygroup.yml --limit-hosts=newhost
<snip>
PLAY [deploy] *************************************************
skipping: no hosts matched
PLAY RECAP ****************************************************
[ERROR]: No plays were matched by any host.
Checking console output
/var/lib/jenkins/jobs/deploy-mygroup/builds/126/log:
skipping: no hosts matched
Build step 'Jenkins Text Finder' changed build result to FAILURE
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10 April 2016

Vincent Bernat: Testing network software with pytest and Linux namespaces

Started in 2008, lldpd is an implementation of IEEE 802.1AB-2005 (aka LLDP) written in C. While it contains some unit tests, like many other network-related software at the time, the coverage of those is pretty poor: they are hard to write because the code is written in an imperative style and tighly coupled with the system. It would require extensive mocking1. While a rewrite (complete or iterative) would help to make the code more test-friendly, it would be quite an effort and it will likely introduce operational bugs along the way. To get better test coverage, the major features of lldpd are now verified through integration tests. Those tests leverage Linux network namespaces to setup a lightweight and isolated environment for each test. They run through pytest, a powerful testing tool.

pytest in a nutshell pytest is a Python testing tool whose primary use is to write tests for Python applications but is versatile enough for other creative usages. It is bundled with three killer features:
  • you can directly use the assert keyword,
  • you can inject fixtures in any test function, and
  • you can parametrize tests.

Assertions With unittest, the unit testing framework included with Python, and many similar frameworks, unit tests have to be encapsulated into a class and use the provided assertion methods. For example:
class testArithmetics(unittest.TestCase):
    def test_addition(self):
        self.assertEqual(1 + 3, 4)
The equivalent with pytest is simpler and more readable:
def test_addition():
    assert 1 + 3 == 4
pytest will analyze the AST and display useful error messages in case of failure. For further information, see Benjamin Peterson s article.

Fixtures A fixture is the set of actions performed in order to prepare the system to run some tests. With classic frameworks, you can only define one fixture for a set of tests:
class testInVM(unittest.TestCase):
    def setUp(self):
        self.vm = VM('Test-VM')
        self.vm.start()
        self.ssh = SSHClient()
        self.ssh.connect(self.vm.public_ip)
    def tearDown(self):
        self.ssh.close()
        self.vm.destroy()
    def test_hello(self):
        stdin, stdout, stderr = self.ssh.exec_command("echo hello")
        stdin.close()
        self.assertEqual(stderr.read(), b"")
        self.assertEqual(stdout.read(), b"hello\n")
In the example above, we want to test various commands on a remote VM. The fixture launches a new VM and configure an SSH connection. However, if the SSH connection cannot be established, the fixture will fail and the tearDown() method won t be invoked. The VM will be left running. Instead, with pytest, we could do this:
@pytest.yield_fixture
def vm():
    r = VM('Test-VM')
    r.start()
    yield r
    r.destroy()
@pytest.yield_fixture
def ssh(vm):
    ssh = SSHClient()
    ssh.connect(vm.public_ip)
    yield ssh
    ssh.close()
def test_hello(ssh):
    stdin, stdout, stderr = ssh.exec_command("echo hello")
    stdin.close()
    stderr.read() == b""
    stdout.read() == b"hello\n"
The first fixture will provide a freshly booted VM. The second one will setup an SSH connection to the VM provided as an argument. Fixtures are used through dependency injection: just give their names in the signature of the test functions and fixtures that need them. Each fixture only handle the lifetime of one entity. Whatever a dependent test function or fixture succeeds or fails, the VM will always be finally destroyed.

Parameters If you want to run the same test several times with a varying parameter, you can dynamically create test functions or use one test function with a loop. With pytest, you can parametrize test functions and fixtures:
@pytest.mark.parametrize("n1, n2, expected", [
    (1, 3, 4),
    (8, 20, 28),
    (-4, 0, -4)])
def test_addition(n1, n2, expected):
    assert n1 + n2 == expected

Testing lldpd The general plan for to test a feature in lldpd is the following:
  1. Setup two namespaces.
  2. Create a virtual link between them.
  3. Spawn a lldpd process in each namespace.
  4. Test the feature in one namespace.
  5. Check with lldpcli we get the expected result in the other.
Here is a typical test using the most interesting features of pytest:
@pytest.mark.skipif('LLDP-MED' not in pytest.config.lldpd.features,
                    reason="LLDP-MED not supported")
@pytest.mark.parametrize("classe, expected", [
    (1, "Generic Endpoint (Class I)"),
    (2, "Media Endpoint (Class II)"),
    (3, "Communication Device Endpoint (Class III)"),
    (4, "Network Connectivity Device")])
def test_med_devicetype(lldpd, lldpcli, namespaces, links,
                        classe, expected):
    links(namespaces(1), namespaces(2))
    with namespaces(1):
        lldpd("-r")
    with namespaces(2):
        lldpd("-M", str(classe))
    with namespaces(1):
        out = lldpcli("-f", "keyvalue", "show", "neighbors", "details")
        assert out['lldp.eth0.lldp-med.device-type'] == expected
First, the test will be executed only if lldpd was compiled with LLDP-MED support. Second, the test is parametrized. We will execute four distinct tests, one for each role that lldpd should be able to take as an LLDP-MED-enabled endpoint. The signature of the test has four parameters that are not covered by the parametrize() decorator: lldpd, lldpcli, namespaces and links. They are fixtures. A lot of magic happen in those to keep the actual tests short:
  • lldpd is a factory to spawn an instance of lldpd. When called, it will setup the current namespace (setting up the chroot, creating the user and group for privilege separation, replacing some files to be distribution-agnostic, ), then call lldpd with the additional parameters provided. The output is recorded and added to the test report in case of failure. The module also contains the creation of the pytest.config.lldpd object that is used to record the features supported by lldpd and skip non-matching tests. You can read fixtures/programs.py for more details.
  • lldpcli is also a factory, but it spawns instances of lldpcli, the client to query lldpd. Moreover, it will parse the output in a dictionary to reduce boilerplate.
  • namespaces is one of the most interesting pieces. It is a factory for Linux namespaces. It will spawn a new namespace or refer to an existing one. It is possible to switch from one namespace to another (with with) as they are contexts. Behind the scene, the factory maintains the appropriate file descriptors for each namespace and switch to them with setns(). Once the test is done, everything is wipped out as the file descriptors are garbage collected. You can read fixtures/namespaces.py for more details. It is quite reusable in other projects2.
  • links contains helpers to handle network interfaces: creation of virtual ethernet link between namespaces, creation of bridges, bonds and VLAN, etc. It relies on the pyroute2 module. You can read fixtures/network.py for more details.
You can see an example of a test run on the Travis build for 0.9.2. Since each test is correctly isolated, it s possible to run parallel tests with pytest -n 10 --boxed. To catch even more bugs, both the address sanitizer (ASAN) and the undefined behavior sanitizer (UBSAN) are enabled. In case of a problem, notably a memory leak, the faulty program will exit with a non-zero exit code and the associated test will fail.

  1. A project like cwrap would definitely help. However, it lacks support for Netlink and raw sockets that are essential in lldpd operations.
  2. There are three main limitations in the use of namespaces with this fixture. First, when creating a user namespace, only root is mapped to the current user. With lldpd, we have two users (root and _lldpd). Therefore, the tests have to run as root. The second limitation is with the PID namespace. It s not possible for a process to switch from one PID namespace to another. When you call setns() on a PID namespace, only children of the current process will be in the new PID namespace. The PID namespace is convenient to ensure everyone gets killed once the tests are terminated but you must keep in mind that /proc must be mounted in children only. The third limitation is that, for some namespaces (PID and user), all threads of a process must be part of the same namespace. Therefore, don t use threads in tests. Use multiprocessing module instead.

9 April 2016

Mart n Ferrari: Come to SunCamp this May!

Do you fancy a hack-camp in a place like this? Swimming pool As you might have heard by now, Ana (Guerrero) and I are organising a small Debian event this spring: the Debian SunCamp 2016. It is going to be different to most other Debian events. Instead of a busy schedule of talks, SunCamp will focus on the hacking and socialising aspect. We have tried to make this event the simplest event possible, both for organisers and attendees. There will be no schedule, except for the meal times at the hotel. But these can be ignored too, there is a lovely bar that serves snacks all day long, and plenty of restaurants and caf s around the village. Caf Caf  terrace One of the things that makes the event simple, is that we have negotiated a flat price for accommodation that includes usage of all the facilities in the hotel, and optionally food. We will give you a booking code, and then you arrange your accommodation as you please, you can even stay longer if you feel like it! The rooms are simple but pretty, and everything has been renovated very recently. Room Room view We are not preparing a talks programme, but we will provide the space and resources for talks if you feel inclined to prepare one. You will have a huge meeting room, divided in 4 areas to reduce noise, where you can hack, have team discussions, or present talks. Hacklab Hacklab Of course, some people will prefer to move their discussions to the outdoor area. Outside Sun   lounge Or just skip the discussion, and have a good time with your Debian friends, playing p tanque, pool, air hockey, arcades, or board games. P tanque Snookers Do you want to see more pictures? Check the full gallery
Debian SunCamp 2016 Hotel Anabel, LLoret de Mar, Province of Girona, Catalonia, Spain May 26-29, 2016

Tempted already? Head to the wikipage and register now, it is only 7 weeks away! Please reserve your room before the end of April. The hotel has reserved a number of rooms for us until that time. You can reserve a room after April, but we can't guarantee the hotel will still have free rooms. Comment

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