Petter Reinholdtsen

Isenkram, Appstream and udev make life as a LEGO builder easier
7th October 2016

The Isenkram system provide a practical and easy way to figure out which packages support the hardware in a given machine. The command line tool isenkram-lookup and the tasksel options provide a convenient way to list and install packages relevant for the current hardware during system installation, both user space packages and firmware packages. The GUI background daemon on the other hand provide a pop-up proposing to install packages when a new dongle is inserted while using the computer. For example, if you plug in a smart card reader, the system will ask if you want to install pcscd if that package isn't already installed, and if you plug in a USB video camera the system will ask if you want to install cheese if cheese is currently missing. This already work just fine.

But Isenkram depend on a database mapping from hardware IDs to package names. When I started no such database existed in Debian, so I made my own data set and included it with the isenkram package and made isenkram fetch the latest version of this database from git using http. This way the isenkram users would get updated package proposals as soon as I learned more about hardware related packages.

The hardware is identified using modalias strings. The modalias design is from the Linux kernel where most hardware descriptors are made available as a strings that can be matched using filename style globbing. It handle USB, PCI, DMI and a lot of other hardware related identifiers.

The downside to the Isenkram specific database is that there is no information about relevant distribution / Debian version, making isenkram propose obsolete packages too. But along came AppStream, a cross distribution mechanism to store and collect metadata about software packages. When I heard about the proposal, I contacted the people involved and suggested to add a hardware matching rule using modalias strings in the specification, to be able to use AppStream for mapping hardware to packages. This idea was accepted and AppStream is now a great way for a package to announce the hardware it support in a distribution neutral way. I wrote a recipe on how to add such meta-information in a blog post last December. If you have a hardware related package in Debian, please announce the relevant hardware IDs using AppStream.

In Debian, almost all packages that can talk to a LEGO Mindestorms RCX or NXT unit, announce this support using AppStream. The effect is that when you insert such LEGO robot controller into your Debian machine, Isenkram will propose to install the packages needed to get it working. The intention is that this should allow the local user to start programming his robot controller right away without having to guess what packages to use or which permissions to fix.

But when I sat down with my son the other day to program our NXT unit using his Debian Stretch computer, I discovered something annoying. The local console user (ie my son) did not get access to the USB device for programming the unit. This used to work, but no longer in Jessie and Stretch. After some investigation and asking around on #debian-devel, I discovered that this was because udev had changed the mechanism used to grant access to local devices. The ConsoleKit mechanism from /lib/udev/rules.d/70-udev-acl.rules no longer applied, because LDAP users no longer was added to the plugdev group during login. Michael Biebl told me that this method was obsolete and the new method used ACLs instead. This was good news, as the plugdev mechanism is a mess when using a remote user directory like LDAP. Using ACLs would make sure a user lost device access when she logged out, even if the user left behind a background process which would retain the plugdev membership with the ConsoleKit setup. Armed with this knowledge I moved on to fix the access problem for the LEGO Mindstorms related packages.

The new system uses a udev tag, 'uaccess'. It can either be applied directly for a device, or is applied in /lib/udev/rules.d/70-uaccess.rules for classes of devices. As the LEGO Mindstorms udev rules did not have a class, I decided to add the tag directly in the udev rules files included in the packages. Here is one example. For the nqc C compiler for the RCX, the /lib/udev/rules.d/60-nqc.rules file now look like this:

SUBSYSTEM=="usb", ACTION=="add", ATTR{idVendor}=="0694", ATTR{idProduct}=="0001", \
    SYMLINK+="rcx-%k", TAG+="uaccess"

I suspect all packages using plugdev in their /lib/udev/rules.d/ files should be changed to use this tag (either directly or indirectly via 70-uaccess.rules). Perhaps a lintian check should be created to detect this?

I've been unable to find good documentation on the uaccess feature. It is unclear to me if the uaccess tag is an internal implementation detail like the udev-acl tag used by /lib/udev/rules.d/70-udev-acl.rules. If it is, I guess the indirect method is the preferred way. Michael asked for more documentation from the systemd project and I hope it will make this clearer. For now I use the generic classes when they exist and is already handled by 70-uaccess.rules, and add the tag directly if no such class exist.

To learn more about the isenkram system, please check out my blog posts tagged isenkram.

To help out making life for LEGO constructors in Debian easier, please join us on our IRC channel #debian-lego and join the Debian LEGO team in the Alioth project we created yesterday. A mailing list is not yet created, but we are working on it. :)

As usual, if you use Bitcoin and want to show your support of my activities, please send Bitcoin donations to my address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

Tags: debian, english, isenkram.
Aftenposten-redaktøren med lua i hånda
9th September 2016

En av dagens nyheter er at Aftenpostens redaktør Espen Egil Hansen bruker forsiden av papiravisen på et åpent brev til Facebooks sjef Mark Zuckerberg om Facebooks fjerning av bilder, tekster og sider de ikke liker. Det må være uvant for redaktøren i avisen Aftenposten å stå med lua i handa og håpe på å bli hørt. Spesielt siden Aftenposten har vært med på å gi Facebook makten de nå demonstrerer at de har. Ved å melde seg inn i Facebook-samfunnet har de sagt ja til bruksvilkårene og inngått en antagelig bindende avtale. Kanskje de skulle lest og vurdert vilkårene litt nærmere før de sa ja, i stedet for å klage over at reglende de har valgt å akseptere blir fulgt? Personlig synes jeg vilkårene er uakseptable og det ville ikke falle meg inn å gå inn på en avtale med slike vilkår. I tillegg til uakseptable vilkår er det mange andre grunner til å unngå Facebook. Du kan finne en solid gjennomgang av flere slike argumenter hos Richard Stallmans side om Facebook.

Jeg håper flere norske redaktører på samme vis må stå med lua i hånden inntil de forstår at de selv er med på å føre samfunnet på ville veier ved å omfavne Facebook slik de gjør når de omtaler og løfter frem saker fra Facebook, og tar i bruk Facebook som distribusjonskanal for sine nyheter. De bidrar til overvåkningssamfunnet og raderer ut lesernes privatsfære når de lenker til Facebook på sine sider, og låser seg selv inne i en omgivelse der det er Facebook, og ikke redaktøren, som sitter med makta.

Men det vil nok ta tid, i et Norge der de fleste nettredaktører deler sine leseres personopplysinger med utenlands etterretning.

For øvrig burde varsleren Edward Snowden få politisk asyl i Norge.

Tags: norsk, surveillance.
E-tjenesten ber om innsyn i eposten til partiene på Stortinget
6th September 2016

I helga kom det et hårreisende forslag fra Lysne II-utvalget satt ned av Forsvarsdepartementet. Lysne II-utvalget var bedt om å vurdere ønskelista til Forsvarets etterretningstjeneste (e-tjenesten), og har kommet med forslag om at e-tjenesten skal få lov til a avlytte all Internett-trafikk som passerer Norges grenser. Få er klar over at dette innebærer at e-tjenesten får tilgang til epost sendt til de fleste politiske partiene på Stortinget. Regjeringspartiet Høyre (@hoyre.no), støttepartiene Venstre (@venstre.no) og Kristelig Folkeparti (@krf.no) samt Sosialistisk Ventreparti (@sv.no) og Miljøpartiet de grønne (@mdg.no) har nemlig alle valgt å ta imot eposten sin via utenlandske tjenester. Det betyr at hvis noen sender epost til noen med en slik adresse vil innholdet i eposten, om dette forslaget blir vedtatt, gjøres tilgjengelig for e-tjenesten. Venstre, Sosialistisk Ventreparti og Miljøpartiet De Grønne har valgt å motta sin epost hos Google, Kristelig Folkeparti har valgt å motta sin epost hos Microsoft, og Høyre har valgt å motta sin epost hos Comendo med mottak i Danmark og Irland. Kun Arbeiderpartiet og Fremskrittspartiet har valgt å motta eposten sin i Norge, hos henholdsvis Intility AS og Telecomputing AS.

Konsekvensen er at epost inn og ut av de politiske organisasjonene, til og fra partimedlemmer og partiets tillitsvalgte vil gjøres tilgjengelig for e-tjenesten for analyse og sortering. Jeg mistenker at kunnskapen som slik blir tilgjengelig vil være nyttig hvis en ønsker å vite hvilke argumenter som treffer publikum når en ønsker å påvirke Stortingets representanter.

Ved hjelp av MX-oppslag i DNS for epost-domene, tilhørende whois-oppslag av IP-adressene og traceroute for å se hvorvidt trafikken går via utlandet kan enhver få bekreftet at epost sendt til de omtalte partiene vil gjøres tilgjengelig for forsvarets etterretningstjeneste hvis forslaget blir vedtatt. En kan også bruke den kjekke nett-tjenesten ipinfo.io for å få en ide om hvor i verden en IP-adresse hører til.

På den positive siden vil forslaget gjøre at enda flere blir motivert til å ta grep for å bruke Tor og krypterte kommunikasjonsløsninger for å kommunisere med sine kjære, for å sikre at privatsfæren vernes. Selv bruker jeg blant annet FreedomBox og Signal til slikt. Ingen av dem er optimale, men de fungerer ganske bra allerede og øker kostnaden for dem som ønsker å invadere mitt privatliv.

For øvrig burde varsleren Edward Snowden få politisk asyl i Norge.

Tags: norsk, surveillance.
First draft Norwegian Bokmål edition of The Debian Administrator's Handbook now public
30th August 2016

In April we started to work on a Norwegian Bokmål edition of the "open access" book on how to set up and administrate a Debian system. Today I am happy to report that the first draft is now publicly available. You can find it on get the Debian Administrator's Handbook page (under Other languages). The first eight chapters have a first draft translation, and we are working on proofreading the content. If you want to help out, please start contributing using the hosted weblate project page, and get in touch using the translators mailing list. Please also check out the instructions for contributors. A good way to contribute is to proofread the text and update weblate if you find errors.

Our goal is still to make the Norwegian book available on paper as well as electronic form.

Tags: debian, english.
Coz can help you find bottlenecks in multi-threaded software - nice free software
11th August 2016

This summer, I read a great article "coz: This Is the Profiler You're Looking For" in USENIX ;login: about how to profile multi-threaded programs. It presented a system for profiling software by running experiences in the running program, testing how run time performance is affected by "speeding up" parts of the code to various degrees compared to a normal run. It does this by slowing down parallel threads while the "faster up" code is running and measure how this affect processing time. The processing time is measured using probes inserted into the code, either using progress counters (COZ_PROGRESS) or as latency meters (COZ_BEGIN/COZ_END). It can also measure unmodified code by measuring complete the program runtime and running the program several times instead.

The project and presentation was so inspiring that I would like to get the system into Debian. I created a WNPP request for it and contacted upstream to try to make the system ready for Debian by sending patches. The build process need to be changed a bit to avoid running 'git clone' to get dependencies, and to include the JavaScript web page used to visualize the collected profiling information included in the source package. But I expect that should work out fairly soon.

The way the system work is fairly simple. To run an coz experiment on a binary with debug symbols available, start the program like this:

coz run --- program-to-run

This will create a text file profile.coz with the instrumentation information. To show what part of the code affect the performance most, use a web browser and either point it to http://plasma-umass.github.io/coz/ or use the copy from git (in the gh-pages branch). Check out this web site to have a look at several example profiling runs and get an idea what the end result from the profile runs look like. To make the profiling more useful you include <coz.h> and insert the COZ_PROGRESS or COZ_BEGIN and COZ_END at appropriate places in the code, rebuild and run the profiler. This allow coz to do more targeted experiments.

A video published by ACM presenting the Coz profiler is available from Youtube. There is also a paper from the 25th Symposium on Operating Systems Principles available titled Coz: finding code that counts with causal profiling.

The source code for Coz is available from github. It will only build with clang because it uses a C++ feature missing in GCC, but I've submitted a patch to solve it and hope it will be included in the upstream source soon.

Please get in touch if you, like me, would like to see this piece of software in Debian. I would very much like some help with the packaging effort, as I lack the in depth knowledge on how to package C++ libraries.

Tags: debian, english, nice free software.
Sales number for the Free Culture translation, first half of 2016
5th August 2016

As my regular readers probably remember, the last year I published a French and Norwegian translation of the classic Free Culture book by the founder of the Creative Commons movement, Lawrence Lessig. A bit less known is the fact that due to the way I created the translations, using docbook and po4a, I also recreated the English original. And because I already had created a new the PDF edition, I published it too. The revenue from the books are sent to the Creative Commons Corporation. In other words, I do not earn any money from this project, I just earn the warm fuzzy feeling that the text is available for a wider audience and more people can learn why the Creative Commons is needed.

Today, just for fun, I had a look at the sales number over at Lulu.com, which take care of payment, printing and shipping. Much to my surprise, the English edition is selling better than both the French and Norwegian edition, despite the fact that it has been available in English since it was first published. In total, 24 paper books was sold for USD $19.99 between 2016-01-01 and 2016-07-31:

Title / languageQuantity
Culture Libre / French3
Fri kultur / Norwegian7
Free Culture / English14

The books are available both from Lulu.com and from large book stores like Amazon and Barnes&Noble. Most revenue, around $10 per book, is sent to the Creative Commons project when the book is sold directly by Lulu.com. The other channels give less revenue. The summary from Lulu tell me 10 books was sold via the Amazon channel, 10 via Ingram (what is this?) and 4 directly by Lulu. And Lulu.com tells me that the revenue sent so far this year is USD $101.42. No idea what kind of sales numbers to expect, so I do not know if that is a good amount of sales for a 10 year old book or not. But it make me happy that the buyers find the book, and I hope they enjoy reading it as much as I did.

The ebook edition is available for free from Github.

If you would like to translate and publish the book in your native language, I would be happy to help make it happen. Please get in touch.

Tags: docbook, english, freeculture.
Vitenskapen tar som vanlig feil igjen - relativt feil
1st August 2016

For mange år siden leste jeg en klassisk tekst som gjorde såpass inntrykk på meg at jeg husker den fortsatt, flere år senere, og bruker argumentene fra den stadig vekk. Teksten var «The Relativity of Wrong» som Isaac Asimov publiserte i Skeptical Inquirer i 1989. Den gir litt perspektiv rundt formidlingen av vitenskapelige resultater. Jeg har hatt lyst til å kunne dele den også med folk som ikke behersker engelsk så godt, som barn og noen av mine eldre slektninger, og har savnet å ha den tilgjengelig på norsk. For to uker siden tok jeg meg sammen og kontaktet Asbjørn Dyrendal i foreningen Skepsis om de var interessert i å publisere en norsk utgave på bloggen sin, og da han var positiv tok jeg kontakt med Skeptical Inquirer og spurte om det var greit for dem. I løpet av noen dager fikk vi tilbakemelding fra Barry Karr hos The Skeptical Inquirer som hadde sjekket og fått OK fra Robyn Asimov som representerte arvingene i Asmiov-familien og gikk igang med oversettingen.

Resultatet, «Relativt feil», ble publisert på skepsis-bloggen for noen minutter siden. Jeg anbefaler deg på det varmeste å lese denne teksten og dele den med dine venner.

For å håndtere oversettelsen og sikre at original og oversettelse var i sync brukte vi git, po4a, GNU make og Transifex. Det hele fungerte utmerket og gjorde det enkelt å dele tekstene og jobbe sammen om finpuss på formuleringene. Hadde hosted.weblate.org latt meg opprette nye prosjekter selv i stedet for å måtte kontakte administratoren der, så hadde jeg brukt weblate i stedet.

Tags: norsk, skepsis.
Techno TV broadcasting live across Norway and the Internet (#debconf16, #nuug) on @frikanalen
1st August 2016

Did you know there is a TV channel broadcasting talks from DebConf 16 across an entire country? Or that there is a TV channel broadcasting talks by or about Linus Torvalds, Tor, OpenID, Common Lisp, Civic Tech, EFF founder John Barlow, how to make 3D printer electronics and many more fascinating topics? It works using only free software (all of it available from Github), and is administrated using a web browser and a web API.

The TV channel is the Norwegian open channel Frikanalen, and I am involved via the NUUG member association in running and developing the software for the channel. The channel is organised as a member organisation where its members can upload and broadcast what they want (think of it as Youtube for national broadcasting television). Individuals can broadcast too. The time slots are handled on a first come, first serve basis. Because the channel have almost no viewers and very few active members, we can experiment with TV technology without too much flack when we make mistakes. And thanks to the few active members, most of the slots on the schedule are free. I see this as an opportunity to spread knowledge about technology and free software, and have a script I run regularly to fill up all the open slots the next few days with technology related video. The end result is a channel I like to describe as Techno TV - filled with interesting talks and presentations.

It is available on channel 50 on the Norwegian national digital TV network (RiksTV). It is also available as a multicast stream on Uninett. And finally, it is available as a WebM unicast stream from Frikanalen and NUUG. Check it out. :)

Tags: english, frikanalen, nuug, video.
Unlocking HTC Desire HD on Linux using unruu and fastboot
7th July 2016

Yesterday, I tried to unlock a HTC Desire HD phone, and it proved to be a slight challenge. Here is the recipe if I ever need to do it again. It all started by me wanting to try the recipe to set up an hardened Android installation from the Tor project blog on a device I had access to. It is a old mobile phone with a broken microphone The initial idea had been to just install CyanogenMod on it, but did not quite find time to start on it until a few days ago.

The unlock process is supposed to be simple: (1) Boot into the boot loader (press volume down and power at the same time), (2) select 'fastboot' before (3) connecting the device via USB to a Linux machine, (4) request the device identifier token by running 'fastboot oem get_identifier_token', (5) request the device unlocking key using the HTC developer web site and unlock the phone using the key file emailed to you.

Unfortunately, this only work fi you have hboot version 2.00.0029 or newer, and the device I was working on had 2.00.0027. This apparently can be easily fixed by downloading a Windows program and running it on your Windows machine, if you accept the terms Microsoft require you to accept to use Windows - which I do not. So I had to come up with a different approach. I got a lot of help from AndyCap on #nuug, and would not have been able to get this working without him.

First I needed to extract the hboot firmware from the windows binary for HTC Desire HD downloaded as 'the RUU' from HTC. For this there is is a github project named unruu using libunshield. The unshield tool did not recognise the file format, but unruu worked and extracted rom.zip, containing the new hboot firmware and a text file describing which devices it would work for.

Next, I needed to get the new firmware into the device. For this I followed some instructions available from HTC1Guru.com, and ran these commands as root on a Linux machine with Debian testing:

adb reboot-bootloader
fastboot oem rebootRUU
fastboot flash zip rom.zip
fastboot flash zip rom.zip
fastboot reboot

The flash command apparently need to be done twice to take effect, as the first is just preparations and the second one do the flashing. The adb command is just to get to the boot loader menu, so turning the device on while holding volume down and the power button should work too.

With the new hboot version in place I could start following the instructions on the HTC developer web site. I got the device token like this:

fastboot oem get_identifier_token 2>&1 | sed 's/(bootloader) //'

And once I got the unlock code via email, I could use it like this:

fastboot flash unlocktoken Unlock_code.bin

And with that final step in place, the phone was unlocked and I could start stuffing the software of my own choosing into the device. So far I only inserted a replacement recovery image to wipe the phone before I start. We will see what happen next. Perhaps I should install Debian on it. :)

Tags: bootsystem, debian, english, opphavsrett, sikkerhet.
How to use the Signal app if you only have a land line (ie no mobile phone)
3rd July 2016

For a while now, I have wanted to test the Signal app, as it is said to provide end to end encrypted communication and several of my friends and family are already using it. As I by choice do not own a mobile phone, this proved to be harder than expected. And I wanted to have the source of the client and know that it was the code used on my machine. But yesterday I managed to get it working. I used the Github source, compared it to the source in the Signal Chrome app available from the Chrome web store, applied patches to use the production Signal servers, started the app and asked for the hidden "register without a smart phone" form. Here is the recipe how I did it.

First, I fetched the Signal desktop source from Github, using

git clone https://github.com/WhisperSystems/Signal-Desktop.git

Next, I patched the source to use the production servers, to be able to talk to other Signal users:

cat <<EOF | patch -p0
diff -ur ./js/background.js userdata/Default/Extensions/bikioccmkafdpakkkcpdbppfkghcmihk/0.15.0_0/js/background.js
--- ./js/background.js  2016-06-29 13:43:15.630344628 +0200
+++ userdata/Default/Extensions/bikioccmkafdpakkkcpdbppfkghcmihk/0.15.0_0/js/background.js    2016-06-29 14:06:29.530300934 +0200
@@ -47,8 +47,8 @@
         });
     });
 
-    var SERVER_URL = 'https://textsecure-service-staging.whispersystems.org';
-    var ATTACHMENT_SERVER_URL = 'https://whispersystems-textsecure-attachments-staging.s3.amazonaws.com';
+    var SERVER_URL = 'https://textsecure-service-ca.whispersystems.org:4433';
+    var ATTACHMENT_SERVER_URL = 'https://whispersystems-textsecure-attachments.s3.amazonaws.com';
     var messageReceiver;
     window.getSocketStatus = function() {
         if (messageReceiver) {
diff -ur ./js/expire.js userdata/Default/Extensions/bikioccmkafdpakkkcpdbppfkghcmihk/0.15.0_0/js/expire.js
--- ./js/expire.js      2016-06-29 13:43:15.630344628 +0200
+++ userdata/Default/Extensions/bikioccmkafdpakkkcpdbppfkghcmihk/0.15.0_0/js/expire.js2016-06-29 14:06:29.530300934 +0200
@@ -1,6 +1,6 @@
 ;(function() {
     'use strict';
-    var BUILD_EXPIRATION = 0;
+    var BUILD_EXPIRATION = 1474492690000;
 
     window.extension = window.extension || {};
 
EOF

The first part is changing the servers, and the second is updating an expiration timestamp. This timestamp need to be updated regularly. It is set 90 days in the future by the build process (Gruntfile.js). The value is seconds since 1970 times 1000, as far as I can tell.

Based on a tip and good help from the #nuug IRC channel, I wrote a script to launch Signal in Chromium.

#!/bin/sh
cd $(dirname $0)
mkdir -p userdata
exec chromium \
  --proxy-server="socks://localhost:9050" \
  --user-data-dir=`pwd`/userdata --load-and-launch-app=`pwd`

The script start the app and configure Chromium to use the Tor SOCKS5 proxy to make sure those controlling the Signal servers (today Amazon and Whisper Systems) as well as those listening on the lines will have a harder time location my laptop based on the Signal connections if they use source IP address.

When the script starts, one need to follow the instructions under "Standalone Registration" in the CONTRIBUTING.md file in the git repository. I right clicked on the Signal window to get up the Chromium debugging tool, visited the 'Console' tab and wrote 'extension.install("standalone")' on the console prompt to get the registration form. Then I entered by land line phone number and pressed 'Call'. 5 seconds later the phone rang and a robot voice repeated the verification code three times. After entering the number into the verification code field in the form, I could start using Signal from my laptop.

As far as I can tell, The Signal app will leak who is talking to whom and thus who know who to those controlling the central server, but such leakage is hard to avoid with a centrally controlled server setup. It is something to keep in mind when using Signal - the content of your chats are harder to intercept, but the meta data exposing your contact network is available to people you do not know. So better than many options, but not great. And sadly the usage is connected to my land line, thus allowing those controlling the server to associate it to my home and person. I would prefer it if only those I knew could tell who I was on Signal. There are options avoiding such information leakage, but most of my friends are not using them, so I am stuck with Signal for now.

Tags: debian, english, sikkerhet, surveillance.

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