Search Results: "Petter Reinholdtsen"

18 November 2017

Petter Reinholdtsen: Legal to share more than 3000 movies listed on IMDB?

A month ago, I blogged about my work to automatically check the copyright status of IMDB entries, and try to count the number of movies listed in IMDB that is legal to distribute on the Internet. I have continued to look for good data sources, and identified a few more. The code used to extract information from various data sources is available in a git repository, currently available from github. So far I have identified 3186 unique IMDB title IDs. To gain better understanding of the structure of the data set, I created a histogram of the year associated with each movie (typically release year). It is interesting to notice where the peaks and dips in the graph are located. I wonder why they are placed there. I suspect World War II caused the dip around 1940, but what caused the peak around 2010?

I've so far identified ten sources for IMDB title IDs for movies in the public domain or with a free license. This is the statistics reported when running 'make stats' in the git repository:

  249 entries (    6 unique) with and   288 without IMDB title ID in free-movies-archive-org-butter.json
 2301 entries (  540 unique) with and     0 without IMDB title ID in free-movies-archive-org-wikidata.json
  830 entries (   29 unique) with and     0 without IMDB title ID in free-movies-icheckmovies-archive-mochard.json
 2109 entries (  377 unique) with and     0 without IMDB title ID in free-movies-imdb-pd.json
  291 entries (  122 unique) with and     0 without IMDB title ID in free-movies-letterboxd-pd.json
  144 entries (  135 unique) with and     0 without IMDB title ID in free-movies-manual.json
  350 entries (    1 unique) with and   801 without IMDB title ID in free-movies-publicdomainmovies.json
    4 entries (    0 unique) with and   124 without IMDB title ID in free-movies-publicdomainreview.json
  698 entries (  119 unique) with and   118 without IMDB title ID in free-movies-publicdomaintorrents.json
    8 entries (    8 unique) with and   196 without IMDB title ID in free-movies-vodo.json
 3186 unique IMDB title IDs in total
The entries without IMDB title ID are candidates to increase the data set, but might equally well be duplicates of entries already listed with IMDB title ID in one of the other sources, or represent movies that lack a IMDB title ID. I've seen examples of all these situations when peeking at the entries without IMDB title ID. Based on these data sources, the lower bound for movies listed in IMDB that are legal to distribute on the Internet is between 3186 and 4713. It would be great for improving the accuracy of this measurement, if the various sources added IMDB title ID to their metadata. I have tried to reach the people behind the various sources to ask if they are interested in doing this, without any replies so far. Perhaps you can help me get in touch with the people behind VODO, Public Domain Torrents, Public Domain Movies and Public Domain Review to try to convince them to add more metadata to their movie entries? Another way you could help is by adding pages to Wikipedia about movies that are legal to distribute on the Internet. If such page exist and include a link to both IMDB and The Internet Archive, the script used to generate free-movies-archive-org-wikidata.json should pick up the mapping as soon as wikidata is updates. As usual, if you use Bitcoin and want to show your support of my activities, please send Bitcoin donations to my address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

01 November 2017

Petter Reinholdtsen: Some notes on fault tolerant storage systems

If you care about how fault tolerant your storage is, you might find these articles and papers interesting. They have formed how I think of when designing a storage system. Several of these research papers are based on data collected from hundred thousands or millions of disk, and their findings are eye opening. The short story is simply do not implicitly trust RAID or redundant storage systems. Details matter. And unfortunately there are few options on Linux addressing all the identified issues. Both ZFS and Btrfs are doing a fairly good job, but have legal and practical issues on their own. I wonder how cluster file systems like Ceph do in this regard. After all, there is an old saying, you know you have a distributed system when the crash of a compyter you have never heard of stops you from getting any work done. The same holds true if fault tolerance do not work. Just remember, in the end, it do not matter how redundant, or how fault tolerant your storage is, if you do not continuously monitor its status to detect and replace failed disks.

31 October 2017

Petter Reinholdtsen: Web services for writing academic LaTeX papers as a team

I was surprised today to learn that a friend in academia did not know there are easily available web services available for writing LaTeX documents as a team. I thought it was common knowledge, but to make sure at least my readers are aware of it, I would like to mention these useful services for writing LaTeX documents. Some of them even provide a WYSIWYG editor to ease writing even further. There are two commercial services available, ShareLaTeX and Overleaf. They are very easy to use. Just start a new document, select which publisher to write for (ie which LaTeX style to use), and start writing. Note, these two have announced their intention to join forces, so soon it will only be one joint service. I've used both for different documents, and they work just fine. While ShareLaTeX is free software, while the latter is not. According to a announcement from Overleaf, they plan to keep the ShareLaTeX code base maintained as free software. But these two are not the only alternatives. Fidus Writer is another free software solution with the source available on github. I have not used it myself. Several others can be found on the nice alterntiveTo web service. If you like Google Docs or Etherpad, but would like to write documents in LaTeX, you should check out these services. You can even host your own, if you want to. :)

25 October 2017

Petter Reinholdtsen: Locating IMDB IDs of movies in the Internet Archive using Wikidata

Recently, I needed to automatically check the copyright status of a set of The Internet Movie database (IMDB) entries, to figure out which one of the movies they refer to can be freely distributed on the Internet. This proved to be harder than it sounds. IMDB for sure list movies without any copyright protection, where the copyright protection has expired or where the movie is lisenced using a permissive license like one from Creative Commons. These are mixed with copyright protected movies, and there seem to be no way to separate these classes of movies using the information in IMDB. First I tried to look up entries manually in IMDB, Wikipedia and The Internet Archive, to get a feel how to do this. It is hard to know for sure using these sources, but it should be possible to be reasonable confident a movie is "out of copyright" with a few hours work per movie. As I needed to check almost 20,000 entries, this approach was not sustainable. I simply can not work around the clock for about 6 years to check this data set. I asked the people behind The Internet Archive if they could introduce a new metadata field in their metadata XML for IMDB ID, but was told that they leave it completely to the uploaders to update the metadata. Some of the metadata entries had IMDB links in the description, but I found no way to download all metadata files in bulk to locate those ones and put that approach aside. In the process I noticed several Wikipedia articles about movies had links to both IMDB and The Internet Archive, and it occured to me that I could use the Wikipedia RDF data set to locate entries with both, to at least get a lower bound on the number of movies on The Internet Archive with a IMDB ID. This is useful based on the assumption that movies distributed by The Internet Archive can be legally distributed on the Internet. With some help from the RDF community (thank you DanC), I was able to come up with this query to pass to the SPARQL interface on Wikidata:
SELECT ?work ?imdb ?ia ?when ?label
  ?work wdt:P31/wdt:P279* wd:Q11424.
  ?work wdt:P345 ?imdb.
  ?work wdt:P724 ?ia.
        ?work wdt:P577 ?when.
        ?work rdfs:label ?label.
        FILTER(LANG(?label) = "en").
If I understand the query right, for every film entry anywhere in Wikpedia, it will return the IMDB ID and The Internet Archive ID, and when the movie was released and its English title, if either or both of the latter two are available. At the moment the result set contain 2338 entries. Of course, it depend on volunteers including both correct IMDB and The Internet Archive IDs in the wikipedia articles for the movie. It should be noted that the result will include duplicates if the movie have entries in several languages. There are some bogus entries, either because The Internet Archive ID contain a typo or because the movie is not available from The Internet Archive. I did not verify the IMDB IDs, as I am unsure how to do that automatically. I wrote a small python script to extract the data set from Wikidata and check if the XML metadata for the movie is available from The Internet Archive, and after around 1.5 hour it produced a list of 2097 free movies and their IMDB ID. In total, 171 entries in Wikidata lack the refered Internet Archive entry. I assume the 70 "disappearing" entries (ie 2338-2097-171) are duplicate entries. This is not too bad, given that The Internet Archive report to contain 5331 feature films at the moment, but it also mean more than 3000 movies are missing on Wikipedia or are missing the pair of references on Wikipedia. I was curious about the distribution by release year, and made a little graph to show how the amount of free movies is spread over the years: I expect the relative distribution of the remaining 3000 movies to be similar. If you want to help, and want to ensure Wikipedia can be used to cross reference The Internet Archive and The Internet Movie Database, please make sure entries like this are listed under the "External links" heading on the Wikipedia article for the movie:
*  Internet Archive film id=FightingLady 
*  IMDb title id=0036823 title=The Fighting Lady 
Please verify the links on the final page, to make sure you did not introduce a typo. Here is the complete list, if you want to correct the 171 identified Wikipedia entries with broken links to The Internet Archive: Q1140317, Q458656, Q458656, Q470560, Q743340, Q822580, Q480696, Q128761, Q1307059, Q1335091, Q1537166, Q1438334, Q1479751, Q1497200, Q1498122, Q865973, Q834269, Q841781, Q841781, Q1548193, Q499031, Q1564769, Q1585239, Q1585569, Q1624236, Q4796595, Q4853469, Q4873046, Q915016, Q4660396, Q4677708, Q4738449, Q4756096, Q4766785, Q880357, Q882066, Q882066, Q204191, Q204191, Q1194170, Q940014, Q946863, Q172837, Q573077, Q1219005, Q1219599, Q1643798, Q1656352, Q1659549, Q1660007, Q1698154, Q1737980, Q1877284, Q1199354, Q1199354, Q1199451, Q1211871, Q1212179, Q1238382, Q4906454, Q320219, Q1148649, Q645094, Q5050350, Q5166548, Q2677926, Q2698139, Q2707305, Q2740725, Q2024780, Q2117418, Q2138984, Q1127992, Q1058087, Q1070484, Q1080080, Q1090813, Q1251918, Q1254110, Q1257070, Q1257079, Q1197410, Q1198423, Q706951, Q723239, Q2079261, Q1171364, Q617858, Q5166611, Q5166611, Q324513, Q374172, Q7533269, Q970386, Q976849, Q7458614, Q5347416, Q5460005, Q5463392, Q3038555, Q5288458, Q2346516, Q5183645, Q5185497, Q5216127, Q5223127, Q5261159, Q1300759, Q5521241, Q7733434, Q7736264, Q7737032, Q7882671, Q7719427, Q7719444, Q7722575, Q2629763, Q2640346, Q2649671, Q7703851, Q7747041, Q6544949, Q6672759, Q2445896, Q12124891, Q3127044, Q2511262, Q2517672, Q2543165, Q426628, Q426628, Q12126890, Q13359969, Q13359969, Q2294295, Q2294295, Q2559509, Q2559912, Q7760469, Q6703974, Q4744, Q7766962, Q7768516, Q7769205, Q7769988, Q2946945, Q3212086, Q3212086, Q18218448, Q18218448, Q18218448, Q6909175, Q7405709, Q7416149, Q7239952, Q7317332, Q7783674, Q7783704, Q7857590, Q3372526, Q3372642, Q3372816, Q3372909, Q7959649, Q7977485, Q7992684, Q3817966, Q3821852, Q3420907, Q3429733, Q774474

14 October 2017

Petter Reinholdtsen: A one-way wall on the border?

I find it fascinating how many of the people being locked inside the proposed border wall between USA and Mexico support the idea. The proposal to keep Mexicans out reminds me of the propaganda twist from the East Germany government calling the wall the Antifascist Bulwark after erecting the Berlin Wall, claiming that the wall was erected to keep enemies from creeping into East Germany, while it was obvious to the people locked inside it that it was erected to keep the people from escaping. Do the people in USA supporting this wall really believe it is a one way wall, only keeping people on the outside from getting in, while not keeping people in the inside from getting out?

09 October 2017

Petter Reinholdtsen: Generating 3D prints in Debian using Cura and Slic3r(-prusa)

At my nearby maker space, Sonen, I heard the story that it was easier to generate gcode files for theyr 3D printers (Ultimake 2+) on Windows and MacOS X than Linux, because the software involved had to be manually compiled and set up on Linux while premade packages worked out of the box on Windows and MacOS X. I found this annoying, as the software involved, Cura, is free software and should be trivial to get up and running on Linux if someone took the time to package it for the relevant distributions. I even found a request for adding into Debian from 2013, which had seem some activity over the years but never resulted in the software showing up in Debian. So a few days ago I offered my help to try to improve the situation. Now I am very happy to see that all the packages required by a working Cura in Debian are uploaded into Debian and waiting in the NEW queue for the ftpmasters to have a look. You can track the progress on the status page for the 3D printer team. The uploaded packages are a bit behind upstream, and was uploaded now to get slots in the NEW queue while we work up updating the packages to the latest upstream version. On a related note, two competitors for Cura, which I found harder to use and was unable to configure correctly for Ultimaker 2+ in the short time I spent on it, are already in Debian. If you are looking for 3D printer "slicers" and want something already available in Debian, check out slic3r and slic3r-prusa. The latter is a fork of the former.

29 September 2017

Petter Reinholdtsen: Visualizing GSM radio chatter using gr-gsm and Hopglass

Every mobile phone announce its existence over radio to the nearby mobile cell towers. And this radio chatter is available for anyone with a radio receiver capable of receiving them. Details about the mobile phones with very good accuracy is of course collected by the phone companies, but this is not the topic of this blog post. The mobile phone radio chatter make it possible to figure out when a cell phone is nearby, as it include the SIM card ID (IMSI). By paying attention over time, one can see when a phone arrive and when it leave an area. I believe it would be nice to make this information more available to the general public, to make more people aware of how their phones are announcing their whereabouts to anyone that care to listen. I am very happy to report that we managed to get something visualizing this information up and running for Oslo Skaperfestival 2017 (Oslo Makers Festival) taking place today and tomorrow at Deichmanske library. The solution is based on the simple recipe for listening to GSM chatter I posted a few days ago, and will show up at the stand of pen Sone from the Computer Science department of the University of Oslo. The presentation will show the nearby mobile phones (aka IMSIs) as dots in a web browser graph, with lines to the dot representing mobile base station it is talking to. It was working in the lab yesterday, and was moved into place this morning. We set up a fairly powerful desktop machine using Debian Buster/Testing with several (five, I believe) RTL2838 DVB-T receivers connected and visualize the visible cell phone towers using an English version of Hopglass. A fairly powerfull machine is needed as the grgsm_livemon_headless processes from gr-gsm converting the radio signal to data packages is quite CPU intensive. The frequencies to listen to, are identified using a slightly patched scan-and-livemon (to set the --args values for each receiver), and the Hopglass data is generated using the patches in my meshviewer-output branch. For some reason we could not get more than four SDRs working. There is also a geographical map trying to show the location of the base stations, but I believe their coordinates are hardcoded to some random location in Germany, I believe. The code should be replaced with code to look up location in a text file, a sqlite database or one of the online databases mentioned in the github issue for the topic. If this sound interesting, visit the stand at the festival!

24 September 2017

Petter Reinholdtsen: Easier recipe to observe the cell phones around you

A little more than a month ago I wrote how to observe the SIM card ID (aka IMSI number) of mobile phones talking to nearby mobile phone base stations using Debian GNU/Linux and a cheap USB software defined radio, and thus being able to pinpoint the location of people and equipment (like cars and trains) with an accuracy of a few kilometer. Since then we have worked to make the procedure even simpler, and it is now possible to do this without any manual frequency tuning and without building your own packages. The gr-gsm package is now included in Debian testing and unstable, and the IMSI-catcher code no longer require root access to fetch and decode the GSM data collected using gr-gsm. Here is an updated recipe, using packages built by Debian and a git clone of two python scripts:
  1. Start with a Debian machine running the Buster version (aka testing).
  2. Run 'apt install gr-gsm python-numpy python-scipy python-scapy' as root to install required packages.
  3. Fetch the code decoding GSM packages using 'git clone'.
  4. Insert USB software defined radio supported by GNU Radio.
  5. Enter the IMSI-catcher directory and run 'python scan-and-livemon' to locate the frequency of nearby base stations and start listening for GSM packages on one of them.
  6. Enter the IMSI-catcher directory and run 'python' to display the collected information.
Note, due to a bug somewhere the scan-and-livemon program (actually its underlying program grgsm_scanner) do not work with the HackRF radio. It does work with RTL 8232 and other similar USB radio receivers you can get very cheaply (for example from ebay), so for now the solution is to scan using the RTL radio and only use HackRF for fetching GSM data. As far as I can tell, a cell phone only show up on one of the frequencies at the time, so if you are going to track and count every cell phone around you, you need to listen to all the frequencies used. To listen to several frequencies, use the --numrecv argument to scan-and-livemon to use several receivers. Further, I am not sure if phones using 3G or 4G will show as talking GSM to base stations, so this approach might not see all phones around you. I typically see 0-400 IMSI numbers an hour when looking around where I live. I've tried to run the scanner on a Raspberry Pi 2 and 3 running Debian Buster, but the grgsm_livemon_headless process seem to be too CPU intensive to keep up. When GNU Radio print 'O' to stdout, I am told there it is caused by a buffer overflow between the radio and GNU Radio, caused by the program being unable to read the GSM data fast enough. If you see a stream of 'O's from the terminal where you started scan-and-livemon, you need a give the process more CPU power. Perhaps someone are able to optimize the code to a point where it become possible to set up RPi3 based GSM sniffers? I tried using Raspbian instead of Debian, but there seem to be something wrong with GNU Radio on raspbian, causing glibc to abort().

09 August 2017

Petter Reinholdtsen: Simpler recipe on how to make a simple $7 IMSI Catcher using Debian

On friday, I came across an interesting article in the Norwegian web based ICT news magazine on how to collect the IMSI numbers of nearby cell phones using the cheap DVB-T software defined radios. The article refered to instructions and a recipe by Keld Norman on Youtube on how to make a simple $7 IMSI Catcher, and I decided to test them out. The instructions said to use Ubuntu, install pip using apt (to bypass apt), use pip to install pybombs (to bypass both apt and pip), and the ask pybombs to fetch and build everything you need from scratch. I wanted to see if I could do the same on the most recent Debian packages, but this did not work because pybombs tried to build stuff that no longer build with the most recent openssl library or some other version skew problem. While trying to get this recipe working, I learned that the apt->pip->pybombs route was a long detour, and the only piece of software dependency missing in Debian was the gr-gsm package. I also found out that the lead upstream developer of gr-gsm (the name stand for GNU Radio GSM) project already had a set of Debian packages provided in an Ubuntu PPA repository. All I needed to do was to dget the Debian source package and built it. The IMSI collector is a python script listening for packages on the loopback network device and printing to the terminal some specific GSM packages with IMSI numbers in them. The code is fairly short and easy to understand. The reason this work is because gr-gsm include a tool to read GSM data from a software defined radio like a DVB-T USB stick and other software defined radios, decode them and inject them into a network device on your Linux machine (using the loopback device by default). This proved to work just fine, and I've been testing the collector for a few days now. The updated and simpler recipe is thus to
  1. start with a Debian machine running Stretch or newer,
  2. build and install the gr-gsm package available from,
  3. clone the git repostory from,
  4. run grgsm_livemon and adjust the frequency until the terminal where it was started is filled with a stream of text (meaning you found a GSM station).
  5. go into the IMSI-catcher directory and run 'sudo python' to extract the IMSI numbers.
To make it even easier in the future to get this sniffer up and running, I decided to package the gr-gsm project for Debian (WNPP #871055), and the package was uploaded into the NEW queue today. Luckily the gnuradio maintainer has promised to help me, as I do not know much about gnuradio stuff yet. I doubt this "IMSI cacher" is anywhere near as powerfull as commercial tools like The Spy Phone Portable IMSI / IMEI Catcher or the Harris Stingray, but I hope the existance of cheap alternatives can make more people realise how their whereabouts when carrying a cell phone is easily tracked. Seeing the data flow on the screen, realizing that I live close to a police station and knowing that the police is also wearing cell phones, I wonder how hard it would be for criminals to track the position of the police officers to discover when there are police near by, or for foreign military forces to track the location of the Norwegian military forces, or for anyone to track the location of government officials... It is worth noting that the data reported by the IMSI-catcher script mentioned above is only a fraction of the data broadcasted on the GSM network. It will only collect one frequency at the time, while a typical phone will be using several frequencies, and not all phones will be using the frequencies tracked by the grgsm_livemod program. Also, there is a lot of radio chatter being ignored by the simple_IMSI-catcher script, which would be collected by extending the parser code. I wonder if gr-gsm can be set up to listen to more than one frequency?

07 August 2017

Raphaël Hertzog: My Free Software Activities in July 2017

My monthly report covers a large part of what I have been doing in the free software world. I write it for my donors (thanks to them!) but also for the wider Debian community because it can give ideas to newcomers and it s one of the best ways to find volunteers to work with me on projects that matter to me. Debian LTS This month I was allocated 12 hours but I only managed to work for 7 hours (due to vacation and unanticipated customer work). I gave back the remaining hours to the pool as I didn t want to carry them over for August which will be also short due to vacation (BTW I m not attending Debconf). I spent my 7 hours doing CVE triaging during the week where I was in charge of the LTS frontdesk (I committed 22 updates to the security tracker). I did publish DLA-1010-1 on vorbis-tools but the package update had been prepared by Petter Reinholdtsen. Misc Debian work zim. I published an updated package in experimental (0.67~rc2-2) with the upstream bug fixes on the current release candidate. The final version has been released during my vacation and I will soon upload it to unstable. Debian Handbook. I worked with Petter Reinholdtsen to finalize the paperback version of the Norwegian translation of the Debian Administrator s Handbook (still covering Debian 8 Jessie). It s now available. Bug reports. I filed a few bugs related to my Kali work. #868678: autopkgtest s setup-testbed script is not friendly to derivatives. #868749: aideinit fails with syntax errors when /etc/debian_version contains spaces. debian-installer. I submitted a few d-i patches that I prepared for a customer who had some specific needs (using the hd-media image to boot the installer from an ISO stored in an LVM logical volume). I made changes to debian-installer-utils (#868848), debian-installer (#868852), and iso-scan (#868859, #868900). Thanks See you next month for a new summary of my activities.

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25 July 2017

Petter Reinholdtsen: Norwegian Bokm l edition of Debian Administrator's Handbook is now available

I finally received a copy of the Norwegian Bokm l edition of "The Debian Administrator's Handbook". This test copy arrived in the mail a few days ago, and I am very happy to hold the result in my hand. We spent around one and a half year translating it. This paperbook edition is available from If you buy it quickly, you save 25% on the list price. The book is also available for download in electronic form as PDF, EPUB and Mobipocket, as can be read online as a web page. This is the second book I publish (the first was the book "Free Culture" by Lawrence Lessig in English, French and Norwegian Bokm l), and I am very excited to finally wrap up this project. I hope "H ndbok for Debian-administratoren" will be well received.

12 June 2017

Petter Reinholdtsen: Updated sales number for my Free Culture paper editions

It is pleasing to see that the work we put down in publishing new editions of the classic Free Culture book by the founder of the Creative Commons movement, Lawrence Lessig, is still being appreciated. I had a look at the latest sales numbers for the paper edition today. Not too impressive, but happy to see some buyers still exist. All the revenue from the books is sent to the Creative Commons Corporation, and they receive the largest cut if you buy directly from Lulu. Most books are sold via Amazon, with Ingram second and only a small fraction directly from Lulu. The ebook edition is available for free from Github.
Title / languageQuantity
2016 jan-jun2016 jul-dec2017 jan-may
Culture Libre / French 3 6 15
Fri kultur / Norwegian 7 1 0
Free Culture / English 14 27 16
Total 24 34 31
A bit sad to see the low sales number on the Norwegian edition, and a bit surprising the English edition still selling so well. 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.

09 June 2017

Petter Reinholdtsen: Release 0.1.1 of free software archive system Nikita announced

I am very happy to report that the Nikita Noark 5 core project tagged its second release today. The free software solution is an implementation of the Norwegian archive standard Noark 5 used by government offices in Norway. These were the changes in version 0.1.1 since version 0.1.0 (from If this sound interesting to you, please contact us on IRC (#nikita on or email (nikita-noark mailing list).

07 June 2017

Petter Reinholdtsen: Idea for storing trusted timestamps in a Noark 5 archive

This is a copy of an email I posted to the nikita-noark mailing list. Please follow up there if you would like to discuss this topic. The background is that we are making a free software archive system based on the Norwegian Noark 5 standard for government archives. I've been wondering a bit lately how trusted timestamps could be stored in Noark 5. Trusted timestamps can be used to verify that some information (document/file/checksum/metadata) have not been changed since a specific time in the past. This is useful to verify the integrity of the documents in the archive. Then it occured to me, perhaps the trusted timestamps could be stored as dokument variants (ie dokumentobjekt referered to from dokumentbeskrivelse) with the filename set to the hash it is stamping? Given a "dokumentbeskrivelse" with an associated "dokumentobjekt", a new dokumentobjekt is associated with "dokumentbeskrivelse" with the same attributes as the stamped dokumentobjekt except these attributes: This assume a service following IETF RFC 3161 is used, which specifiy the given MIME type for replies and the .tsr file ending for the content of such trusted timestamp. As far as I can tell from the Noark 5 specifications, it is OK to have several variants/renderings of a dokument attached to a given dokumentbeskrivelse objekt. It might be stretching it a bit to make some of these variants represent crypto-signatures useful for verifying the document integrity instead of representing the dokument itself. Using the source of the service in formatDetaljer allow several timestamping services to be used. This is useful to spread the risk of key compromise over several organisations. It would only be a problem to trust the timestamps if all of the organisations are compromised. The following oneliner on Linux can be used to generate the tsr file. $input is the path to the file to checksum, and $sha256 is the SHA-256 checksum of the file (ie the ".tsr" value mentioned above).
openssl ts -query -data "$inputfile" -cert -sha256 -no_nonce \
    curl -s -H "Content-Type: application/timestamp-query" \
      --data-binary "@-" > $sha256.tsr
To verify the timestamp, you first need to download the public key of the trusted timestamp service, for example using this command:
wget -O ca-cert.txt \
Note, the public key should be stored alongside the timestamps in the archive to make sure it is also available 100 years from now. It is probably a good idea to standardise how and were to store such public keys, to make it easier to find for those trying to verify documents 100 or 1000 years from now. :) The verification itself is a simple openssl command:
openssl ts -verify -data $inputfile -in $sha256.tsr \
  -CAfile ca-cert.txt -text
Is there any reason this approach would not work? Is it somehow against the Noark 5 specification?

19 March 2017

Petter Reinholdtsen: Free software archive system Nikita now able to store documents

The Nikita Noark 5 core project is implementing the Norwegian standard for keeping an electronic archive of government documents. The Noark 5 standard document the requirement for data systems used by the archives in the Norwegian government, and the Noark 5 web interface specification document a REST web service for storing, searching and retrieving documents and metadata in such archive. I've been involved in the project since a few weeks before Christmas, when the Norwegian Unix User Group announced it supported the project. I believe this is an important project, and hope it can make it possible for the government archives in the future to use free software to keep the archives we citizens depend on. But as I do not hold such archive myself, personally my first use case is to store and analyse public mail journal metadata published from the government. I find it useful to have a clear use case in mind when developing, to make sure the system scratches one of my itches. If you would like to help make sure there is a free software alternatives for the archives, please join our IRC channel (#nikita on and the project mailing list. When I got involved, the web service could store metadata about documents. But a few weeks ago, a new milestone was reached when it became possible to store full text documents too. Yesterday, I completed an implementation of a command line tool archive-pdf to upload a PDF file to the archive using this API. The tool is very simple at the moment, and find existing fonds, series and files while asking the user to select which one to use if more than one exist. Once a file is identified, the PDF is associated with the file and uploaded, using the title extracted from the PDF itself. The process is fairly similar to visiting the archive, opening a cabinet, locating a file and storing a piece of paper in the archive. Here is a test run directly after populating the database with test data using our API tester:
~/src//noark5-tester$ ./archive-pdf mangelmelding/mangler.pdf
using arkiv: Title of the test fonds created 2017-03-18T23:49:32.103446
using arkivdel: Title of the test series created 2017-03-18T23:49:32.103446
 0 - Title of the test case file created 2017-03-18T23:49:32.103446
 1 - Title of the test file created 2017-03-18T23:49:32.103446
Select which mappe you want (or search term): 0
Uploading mangelmelding/mangler.pdf
  PDF title: Mangler i spesifikasjonsdokumentet for NOARK 5 Tjenestegrensesnitt
  File 2017/1: Title of the test case file created 2017-03-18T23:49:32.103446
You can see here how the fonds (arkiv) and serie (arkivdel) only had one option, while the user need to choose which file (mappe) to use among the two created by the API tester. The archive-pdf tool can be found in the git repository for the API tester. In the project, I have been mostly working on the API tester so far, while getting to know the code base. The API tester currently use the HATEOAS links to traverse the entire exposed service API and verify that the exposed operations and objects match the specification, as well as trying to create objects holding metadata and uploading a simple XML file to store. The tester has proved very useful for finding flaws in our implementation, as well as flaws in the reference site and the specification. The test document I uploaded is a summary of all the specification defects we have collected so far while implementing the web service. There are several unclear and conflicting parts of the specification, and we have started writing down the questions we get from implementing it. We use a format inspired by how The Austin Group collect defect reports for the POSIX standard with their instructions for the MANTIS defect tracker system, in lack of an official way to structure defect reports for Noark 5 (our first submitted defect report was a request for a procedure for submitting defect reports :). The Nikita project is implemented using Java and Spring, and is fairly easy to get up and running using Docker containers for those that want to test the current code base. The API tester is implemented in Python.

09 March 2017

Petter Reinholdtsen: Detecting NFS hangs on Linux without hanging yourself...

Over the years, administrating thousand of NFS mounting linux computers at the time, I often needed a way to detect if the machine was experiencing NFS hang. If you try to use df or look at a file or directory affected by the hang, the process (and possibly the shell) will hang too. So you want to be able to detect this without risking the detection process getting stuck too. It has not been obvious how to do this. When the hang has lasted a while, it is possible to find messages like these in dmesg:
nfs: server nfsserver not responding, still trying
nfs: server nfsserver OK
It is hard to know if the hang is still going on, and it is hard to be sure looking in dmesg is going to work. If there are lots of other messages in dmesg the lines might have rotated out of site before they are noticed. While reading through the nfs client implementation in linux kernel code, I came across some statistics that seem to give a way to detect it. The om_timeouts sunrpc value in the kernel will increase every time the above log entry is inserted into dmesg. And after digging a bit further, I discovered that this value show up in /proc/self/mountstats on Linux. The mountstats content seem to be shared between files using the same file system context, so it is enough to check one of the mountstats files to get the state of the mount point for the machine. I assume this will not show lazy umounted NFS points, nor NFS mount points in a different process context (ie with a different filesystem view), but that does not worry me. The content for a NFS mount point look similar to this:
device /dev/mapper/Debian-var mounted on /var with fstype ext3
device nfsserver:/mnt/nfsserver/home0 mounted on /mnt/nfsserver/home0 with fstype nfs statvers=1.1
        opts:   rw,vers=3,rsize=65536,wsize=65536,namlen=255,acregmin=3,acregmax=60,acdirmin=30,acdirmax=60,soft,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=,mountvers=3,mountport=4048,mountproto=udp,local_lock=all
        age:    7863311
        caps:   caps=0x3fe7,wtmult=4096,dtsize=8192,bsize=0,namlen=255
        sec:    flavor=1,pseudoflavor=1
        events: 61063112 732346265 1028140 35486205 16220064 8162542 761447191 71714012 37189 3891185 45561809 110486139 4850138 420353 15449177 296502 52736725 13523379 0 52182 9016896 1231 0 0 0 0 0 
        bytes:  166253035039 219519120027 0 0 40783504807 185466229638 11677877 45561809 
        RPC iostats version: 1.0  p/v: 100003/3 (nfs)
        xprt:   tcp 925 1 6810 0 0 111505412 111480497 109 2672418560317 0 248 53869103 22481820
        per-op statistics
                NULL: 0 0 0 0 0 0 0 0
             GETATTR: 61063106 61063108 0 9621383060 6839064400 453650 77291321 78926132
             SETATTR: 463469 463470 0 92005440 66739536 63787 603235 687943
              LOOKUP: 17021657 17021657 0 3354097764 4013442928 57216 35125459 35566511
              ACCESS: 14281703 14290009 5 2318400592 1713803640 1709282 4865144 7130140
            READLINK: 125 125 0 20472 18620 0 1112 1118
                READ: 4214236 4214237 0 715608524 41328653212 89884 22622768 22806693
               WRITE: 8479010 8494376 22 187695798568 1356087148 178264904 51506907 231671771
              CREATE: 171708 171708 0 38084748 46702272 873 1041833 1050398
               MKDIR: 3680 3680 0 773980 993920 26 23990 24245
             SYMLINK: 903 903 0 233428 245488 6 5865 5917
               MKNOD: 80 80 0 20148 21760 0 299 304
              REMOVE: 429921 429921 0 79796004 61908192 3313 2710416 2741636
               RMDIR: 3367 3367 0 645112 484848 22 5782 6002
              RENAME: 466201 466201 0 130026184 121212260 7075 5935207 5961288
                LINK: 289155 289155 0 72775556 67083960 2199 2565060 2585579
             READDIR: 2933237 2933237 0 516506204 13973833412 10385 3190199 3297917
         READDIRPLUS: 1652839 1652839 0 298640972 6895997744 84735 14307895 14448937
              FSSTAT: 6144 6144 0 1010516 1032192 51 9654 10022
              FSINFO: 2 2 0 232 328 0 1 1
            PATHCONF: 1 1 0 116 140 0 0 0
              COMMIT: 0 0 0 0 0 0 0 0
device binfmt_misc mounted on /proc/sys/fs/binfmt_misc with fstype binfmt_misc
The key number to look at is the third number in the per-op list. It is the number of NFS timeouts experiences per file system operation. Here 22 write timeouts and 5 access timeouts. If these numbers are increasing, I believe the machine is experiencing NFS hang. Unfortunately the timeout value do not start to increase right away. The NFS operations need to time out first, and this can take a while. The exact timeout value depend on the setup. For example the defaults for TCP and UDP mount points are quite different, and the timeout value is affected by the soft, hard, timeo and retrans NFS mount options. The only way I have been able to get working on Debian and RedHat Enterprise Linux for getting the timeout count is to peek in /proc/. But according to Solaris 10 System Administration Guide: Network Services, the 'nfsstat -c' command can be used to get these timeout values. But this do not work on Linux, as far as I can tell. I asked Debian about this, but have not seen any replies yet. Is there a better way to figure out if a Linux NFS client is experiencing NFS hangs? Is there a way to detect which processes are affected? Is there a way to get the NFS mount going quickly once the network problem causing the NFS hang has been cleared? I would very much welcome some clues, as we regularly run into NFS hangs.

08 March 2017

Petter Reinholdtsen: How does it feel to be wiretapped, when you should be doing the wiretapping...

So the new president in the United States of America claim to be surprised to discover that he was wiretapped during the election before he was elected president. He even claim this must be illegal. Well, doh, if it is one thing the confirmations from Snowden documented, it is that the entire population in USA is wiretapped, one way or another. Of course the president candidates were wiretapped, alongside the senators, judges and the rest of the people in USA. Next, the Federal Bureau of Investigation ask the Department of Justice to go public rejecting the claims that Donald Trump was wiretapped illegally. I fail to see the relevance, given that I am sure the surveillance industry in USA believe they have all the legal backing they need to conduct mass surveillance on the entire world. There is even the director of the FBI stating that he never saw an order requesting wiretapping of Donald Trump. That is not very surprising, given how the FISA court work, with all its activity being secret. Perhaps he only heard about it? What I find most sad in this story is how Norwegian journalists present it. In a news reports the other day in the radio from the Norwegian National broadcasting Company (NRK), I heard the journalist claim that 'the FBI denies any wiretapping', while the reality is that 'the FBI denies any illegal wiretapping'. There is a fundamental and important difference, and it make me sad that the journalists are unable to grasp it. Update 2017-03-13: Look like The Intercept report that US Senator Rand Paul confirm what I state above.

03 March 2017

Petter Reinholdtsen: Norwegian Bokm l translation of The Debian Administrator's Handbook complete, proofreading in progress

For almost a year now, we have been working on making a Norwegian Bokm l edition of The Debian Administrator's Handbook. Now, thanks to the tireless effort of Ole-Erik, Ingrid and Andreas, the initial translation is complete, and we are working on the proof reading to ensure consistent language and use of correct computer science terms. The plan is to make the book available on paper, as well as in electronic form. For that to happen, the proof reading must be completed and all the figures need to be translated. If you want to help out, get in touch. A fresh PDF edition in A4 format (the final book will have smaller pages) of the book created every morning is available for proofreading. If you find any errors, please visit Weblate and correct the error. The state of the translation including figures is a useful source for those provide Norwegian bokm l screen shots and figures.

01 March 2017

Petter Reinholdtsen: Unlimited randomness with the ChaosKey?

A few days ago I ordered a small batch of the ChaosKey, a small USB dongle for generating entropy created by Bdale Garbee and Keith Packard. Yesterday it arrived, and I am very happy to report that it work great! According to its designers, to get it to work out of the box, you need the Linux kernel version 4.1 or later. I tested on a Debian Stretch machine (kernel version 4.9), and there it worked just fine, increasing the available entropy very quickly. I wrote a small test oneliner to test. It first print the current entropy level, drain /dev/random, and then print the entropy level for five seconds. Here is the situation without the ChaosKey inserted:
% cat /proc/sys/kernel/random/entropy_avail; \
  dd bs=1M if=/dev/random of=/dev/null count=1; \
  for n in $(seq 1 5); do \
     cat /proc/sys/kernel/random/entropy_avail; \
     sleep 1; \
0+1 oppf ringer inn
0+1 oppf ringer ut
28 byte kopiert, 0,000264565 s, 106 kB/s
The entropy level increases by 3-4 every second. In such case any application requiring random bits (like a HTTPS enabled web server) will halt and wait for more entrpy. And here is the situation with the ChaosKey inserted:
% cat /proc/sys/kernel/random/entropy_avail; \
  dd bs=1M if=/dev/random of=/dev/null count=1; \
  for n in $(seq 1 5); do \
     cat /proc/sys/kernel/random/entropy_avail; \
     sleep 1; \
0+1 oppf ringer inn
0+1 oppf ringer ut
104 byte kopiert, 0,000487647 s, 213 kB/s
Quite the difference. :) I bought a few more than I need, in case someone want to buy one here in Norway. :) Update: The dongle was presented at Debconf last year. You might find the talk recording illuminating. It explains exactly what the source of randomness is, if you are unable to spot it from the schema drawing available from the ChaosKey web site linked at the start of this blog post.

20 February 2017

Petter Reinholdtsen: Detect OOXML files with undefined behaviour?

I just noticed the new Norwegian proposal for archiving rules in the goverment list ECMA-376 / ISO/IEC 29500 (aka OOXML) as valid formats to put in long term storage. Luckily such files will only be accepted based on pre-approval from the National Archive. Allowing OOXML files to be used for long term storage might seem like a good idea as long as we forget that there are plenty of ways for a "valid" OOXML document to have content with no defined interpretation in the standard, which lead to a question and an idea. Is there any tool to detect if a OOXML document depend on such undefined behaviour? It would be useful for the National Archive (and anyone else interested in verifying that a document is well defined) to have such tool available when considering to approve the use of OOXML. I'm aware of the officeotron OOXML validator, but do not know how complete it is nor if it will report use of undefined behaviour. Are there other similar tools available? Please send me an email if you know of any such tool.