> On 26 Nov 2015, at 18:07, Josef 'veloc1ty' Stautner <he...@veloc1ty.de> wrote: > > Hi Tim, > > you hit me hard today because I didn't think about the privacy of the users > :-)
Sorry about that :-( > But the data points for read and write are just average values and the time > series database also only stores the average values. So I don't think that > just by looking at the graph you can track specific Hidden Services or make > other attempts. They would get better precision if they trace the IP of the > server. I think you're right, but it depends on your threat model: * an adversary with access to a router/IXP near your server could get precise bandwidth figures (bytes/second) that way; * an adversary anywhere in the world could see averaged bandwidth figures (kilobytes?/minute) using your graph. I could imagine your users facing either type of adversary. But there might be ways to work around that: * a public graph could average bandwidth over the time period used on Globe (6 hours), or * a private graph could provide as much detail as you like, and be made available over password-protected HTTPS, or as a hidden service with client authentication. Tim > Am 25.11.2015 um 23:33 schrieb Tim Wilson-Brown - teor: >> >>> On 26 Nov 2015, at 05:36, Josef Stautner < >>> <mailto:he...@veloc1ty.de>he...@veloc1ty.de <mailto:he...@veloc1ty.de>> >>> wrote: >>> >>> Hello @all, >>> >>> (I'm not sure if you guys are interested in a topic like this) >>> I wrote a perl script to gather bandwidth data from my Tor exit relay. >>> The script connects to the Tor control socket, fetches the running >>> config to extract the bandwidth limits and the reject rule count. >>> Afterwards the last 60 bw-cache entries are fetched and average values >>> are built for bandwidth in and out. >>> All this performance data is then forwarded to Nagios/Icinga where you >>> can do anything with that values. >>> >>> Every 30 minutes a cronjob renders the graph showing the datapoints of >>> the last 6 houres and uploads the resulting image to my website. You can >>> find the image here (Hint: The values for in and out are stacked): >>> https://blog.veloc1ty.de/bandwidth-large.png >>> <https://blog.veloc1ty.de/bandwidth-large.png> >>> >>> The source of the script can be found here on GitHub: >>> https://github.com/vlcty/check_tor_bandwidth >>> <https://github.com/vlcty/check_tor_bandwidth> >>> It's released under the GPLv3 >>> >>> Maybe somebody will find it usefull :-) >> >> Hi Josef, >> >> Thanks for creating this tool - it looks like a great way for operators to >> keep an eye on their relay. >> >> But I wonder about the privacy implications of making a relay's >> high-resolution bandwidth figures public. >> For example, attacker can correlate a traffic-based attack on a hidden >> service, with a traffic peak on its Guards. >> (I am not sure if any similar attack applies to Exits, or any other role >> Exits may have.) >> We previously moved to a bandwidth statistics interval of 6 hours for this >> reason. >> (That's why the 3 days and 1 month bandwidth graphs are empty on Globe.) >> >> You lose a certain amount of precision moving to a graph, rather than >> reporting exact figures in a data file. >> But I'm not sure if that's enough to avoid the attack I described above. >> >> Tim >> >> Tim Wilson-Brown (teor) >> >> teor2345 at gmail dot com >> PGP 968F094B >> >> teor at blah dot im >> OTR CAD08081 9755866D 89E2A06F E3558B7F B5A9D14F >> >> >> >> _______________________________________________ >> tor-relays mailing list >> tor-relays@lists.torproject.org <mailto:tor-relays@lists.torproject.org> >> https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays >> <https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays> > > _______________________________________________ > tor-relays mailing list > tor-relays@lists.torproject.org > https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays Tim Wilson-Brown (teor) teor2345 at gmail dot com PGP 968F094B teor at blah dot im OTR CAD08081 9755866D 89E2A06F E3558B7F B5A9D14F
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