Petter Reinholdtsen

Entries from January 2016.

Creepy, visualise geotagged social media information - nice free software
24th January 2016

Most people seem not to realise that every time they walk around with the computerised radio beacon known as a mobile phone their position is tracked by the phone company and often stored for a long time (like every time a SMS is received or sent). And if their computerised radio beacon is capable of running programs (often called mobile apps) downloaded from the Internet, these programs are often also capable of tracking their location (if the app requested access during installation). And when these programs send out information to central collection points, the location is often included, unless extra care is taken to not send the location. The provided information is used by several entities, for good and bad (what is good and bad, depend on your point of view). What is certain, is that the private sphere and the right to free movement is challenged and perhaps even eradicated for those announcing their location this way, when they share their whereabouts with private and public entities.

The phone company logs provide a register of locations to check out when one want to figure out what the tracked person was doing. It is unavailable for most of us, but provided to selected government officials, company staff, those illegally buying information from unfaithful servants and crackers stealing the information. But the public information can be collected and analysed, and a free software tool to do so is called Creepy or I discovered it when I read an article about Creepy in the Norwegian newspaper Aftenposten i November 2014, and decided to check if it was available in Debian. The python program was in Debian, but the version in Debian was completely broken and practically unmaintained. I uploaded a new version which did not work quite right, but did not have time to fix it then. This Christmas I decided to finally try to get Creepy operational in Debian. Now a fixed version is available in Debian unstable and testing, and almost all Debian specific patches are now included upstream.

The Creepy program visualises geolocation information fetched from Twitter, Instagram, Flickr and Google+, and allow one to get a complete picture of every social media message posted recently in a given area, or track the movement of a given individual across all these services. Earlier it was possible to use the search API of at least some of these services without identifying oneself, but these days it is impossible. This mean that to use Creepy, you need to configure it to log in as yourself on these services, and provide information to them about your search interests. This should be taken into account when using Creepy, as it will also share information about yourself with the services.

The picture above show the twitter messages sent from (or at least geotagged with a position from) the city centre of Oslo, the capital of Norway. One useful way to use Creepy is to first look at information tagged with an area of interest, and next look at all the information provided by one or more individuals who was in the area. I tested it by checking out which celebrity provide their location in twitter messages by checkout out who sent twitter messages near a Norwegian TV station, and next could track their position over time, making it possible to locate their home and work place, among other things. A similar technique have been used to locate Russian soldiers in Ukraine, and it is both a powerful tool to discover lying governments, and a useful tool to help people understand the value of the private information they provide to the public.

The package is not trivial to backport to Debian Stable/Jessie, as it depend on several python modules currently missing in Jessie (at least python-instagram, python-flickrapi and python-requests-toolbelt).

(I have uploaded the image to and licensed it under the same terms as the Creepy program in Debian.)

Tags: debian, english, nice free software.
Always download Debian packages using Tor - the simple recipe
15th January 2016

During his DebConf15 keynote, Jacob Appelbaum observed that those listening on the Internet lines would have good reason to believe a computer have a given security hole if it download a security fix from a Debian mirror. This is a good reason to always use encrypted connections to the Debian mirror, to make sure those listening do not know which IP address to attack. In August, Richard Hartmann observed that encryption was not enough, when it was possible to interfere download size to security patches or the fact that download took place shortly after a security fix was released, and proposed to always use Tor to download packages from the Debian mirror. He was not the first to propose this, as the apt-transport-tor package by Tim Retout already existed to make it easy to convince apt to use Tor, but I was not aware of that package when I read the blog post from Richard.

Richard discussed the idea with Peter Palfrader, one of the Debian sysadmins, and he set up a Tor hidden service on one of the central Debian mirrors using the address vwakviie2ienjx6t.onion, thus making it possible to download packages directly between two tor nodes, making sure the network traffic always were encrypted.

Here is a short recipe for enabling this on your machine, by installing apt-transport-tor and replacing http and https urls with tor+http and tor+https, and using the hidden service instead of the official Debian mirror site. I recommend installing etckeeper before you start to have a history of the changes done in /etc/.

apt install apt-transport-tor
sed -i 's% tor+http://vwakviie2ienjx6t.onion/%' /etc/apt/sources.list
sed -i 's% http% tor+http%' /etc/apt/sources.list

If you have more sources listed in /etc/apt/sources.list.d/, run the sed commands for these too. The sed command is assuming your are using the Debian mirror. Adjust the command (or just edit the file manually) to match your mirror.

This work in Debian Jessie and later. Note that tools like apt-file only recently started using the apt transport system, and do not work with these tor+http URLs. For apt-file you need the version currently in experimental, which need a recent apt version currently only in unstable. So if you need a working apt-file, this is not for you.

Another advantage from this change is that your machine will start using Tor regularly and at fairly random intervals (every time you update the package lists or upgrade or install a new package), thus masking other Tor traffic done from the same machine. Using Tor will become normal for the machine in question.

On Freedombox, APT is set up by default to use apt-transport-tor when Tor is enabled. It would be great if it was the default on any Debian system.

Tags: debian, english, sikkerhet.
Nedlasting fra NRK, som Matroska med undertekster
2nd January 2016

Det kommer stadig nye løsninger for å ta lagre unna innslag fra NRK for å se på det senere. For en stund tilbake kom jeg over et script nrkopptak laget av Ingvar Hagelund. Han fjernet riktignok sitt script etter forespørsel fra Erik Bolstad i NRK, men noen tok heldigvis og gjorde det tilgjengelig via github.

Scriptet kan lagre som MPEG4 eller Matroska, og bake inn undertekster i fila på et vis som blant annet VLC forstår. For å bruke scriptet, kopier ned git-arkivet og kjør

nrkopptak/bin/nrk-opptak k

URL-eksemplet er dagens toppsak på Argument 'k' ber scriptet laste ned og lagre som Matroska. Det finnes en rekke andre muligheter for valg av kvalitet og format.

Jeg foretrekker dette scriptet fremfor youtube-dl, som nevnt i 2014 støtter NRK og en rekke andre videokilder, på grunn av at nrkopptak samler undertekster og video i en enkelt fil, hvilket gjør håndtering enklere på disk.

Tags: multimedia, norsk, video, web.

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