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Nick's August 2012 status report
by Nick Mathewson 01 Sep '12

01 Sep '12

THINGS I DID IN AUGUST I spent a few days vacationing with my family in Maine; took a day off for my birthday, and generally chilled out. I merged lots of bugfixes and patches -- some mine, some other people's, some requiring rewriting and review, some not. This included some security-related stuff that lost me a little sleep. It also involved hacking on some neat patches from Stewart Smith (with help from Jim Meyering) to revamp our build system. We put out a new 0.2.2. I fixed the more important (fixable) bugs in 0.2.3 (notably 6507 and 6244 and 6404), and pushed back on some others. IMO we're now ready to release the (probably) last 0.2.3.x-rc. I merged more patches into 0.2.4; see the new changes files there for more info. Lots of these were ipv6-related stuff from Linus. I started a draft for BEGIN2 cells so I can try to get a more future-proof IPv6 protocol implementation. This is blocked while I teach myself how DNSSEC works once and for all. I tried to get a little more testing on alternatives to our current (bogus, deteriorating) geoip supplier (see #6266) but didn't get anything beyond my older inconclusive results. I started working on an implementation for proposal 200, and a revised 202. With help from some libevent users, I fixed an SSL bug that might have been one of the (probably several) things making SSL bufferevents unstable. The fix appears in libevent 2.0.20-stable. I agreed to fly out to SF to accept the EFF's pioneer awards on Tor's behalf. I had an anniversary and a birthday. I proposed a crazy idea about a separate 0.2.3.x branch for DAs. I chatted a little about metaformats, and spent a while catching up on the ones I didn't know the details of. Currently I'm thinking YAML is a hot mess, and ProtocolBuffers is not too bad actually. There was this insane stegotorus bug that I sort of tracked down. That is, I can tell you which libevent commit to revert in order to make the problem go away (that is, 3467f2fa3bbff0dab6865), but I can't for the life of me figure out what's wrong with it. My current guess is that it provokes an issue somewhere else. A couple of friends/acquaintances approached me about working for Tor as a project manager. I told them to email jobs(a)torproject.org. I don't think we've heard from them yet. It would rock if we had a faster release schedule. I've been trying to find projects our size that do it right. This coming month I must help Linus get our September IPv6 deliverables deployed. I need to help Andrea get her refactored channel abstraction merged, and make sure she's got more stuff to do (and more interesting stuff to do!) as she transitions to full-time. I must get that blog post I'm cowriting with Steven finished, and our paper for November started. And I need to write some of my own code too. I also need to finalize a plan and a schedule for 0.2.4 and send them to the world. "when in danger or in doubt," -- Nick

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[GSoC] [Stegotorus] Recent activities
by vmon 31 Aug '12

31 Aug '12

Hey Zack, I know you are super busy packing for your big move, but I thought as tomorrow is the hard deadline for GSoC, is not a bad ideas to give you some final update. So most of last week I spent on the conflict that occurred between libcurl and libevent having their eyes on the same socket. I tried different ugly and uglier solutions but finally settled on this one which is not that bad: http://stackoverflow.com/questions/12021217/how-to-ask-libcurl-not-to-liste… After that, I'm passing all time line tests now. However, when I look at the client log, I see that some of the sequence no are missing in the recv: like this 203.7169 [debug] recv: <3.81> receiving block 42 <d=0 p=9 f=DAT> T:203.7170: ckt 3 <ntp 1 outq 0>: recv 42 <d=0 p=9 f=DAT> and the next recv is like this: 203.7926 [debug] recv: <3.99> receiving block 60 <d=0 p=1 f=DAT> T:203.7927: ckt 3 <ntp 1 outq 0>: recv 60 <d=0 p=1 f=DAT> Is this for sure an error and loss of data? or there is a normal situation that such a thing can happen? For example when the whole block can't be sent over one connection? (otherwise how do the tl tests all pass?). Further more, I merged the payload scraper and stegotorus. I this way, http_apache checks for the payload database and if it's not there it calls the scraper (it needs apache to be installed on the same machine). These all are commited on the github. I started writing a unit test that fetch a webpage directly (using curl) and through stegotorus and check if they are the same. I thought curl is best approximation of a browser that is available to us. But as I don't think I can finish that till tomorrow, I'm going to spend the remaining time on documenting the 'uri transport protocol' and deal with small issues. After we are done with the evaluation, I'll go back to unit testing. Thanks for your help. Cheers, vmon

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Re: [tor-dev] TBB Gentoo ebuild
by julian 27 Aug '12

27 Aug '12

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 12 Aug 22:56 Mansour Moufid: > Even with webrsync you still have to trust the mirror(s), and then > the Gentoo release infrastructure... Forgive me my bluntness, but how is that different from trusting you? The methods are reliable, being Manifests and webrsync, the unknown variable is the trust you give the ones providing you with ebuilds. But those are identified by gpg on both levels. And the TBB is even worse, cause I also have to trust what's in the binaries. There is no way to tell what was actually compiled there. It could be something different than the sources on the git server. 13 Aug 00:28 Matthew Finkel: > 4) Given 3), is there a reason Tor is not at least an optional > RDEPEND for torbrowser via a USE flag (or another way)? There are no optional runtime-only dependencies in gentoo, this could change with GLEP 62. http://www.gentoo.org/proj/en/glep/glep-0062.html I could however tell the user after compilation that he might want to use tor with this...erm... but I thought that's obvious. The fact that it's not forced for RDEPEND is simply, because there are setups where this is not wanted/required. 13 Aug 00:28 Matthew Finkel: > 5) If you did/do intend to create an ebuild for the TBB and not > just the browser, it should provide the exact same experience as if > the user downloaded it from torproject.org. I think this should > include Vidalia launching Torbrowser once the network is > configured. Definitely not. The intention is not to provide an all-in-one experience. I already had those arguments with the guys from #tor All I am interested in is the question about the firefox build-time configuration and if different build-time configurations could lead to vulnerability in the tor network. If there is the slightest doubt about that, I will remove this ebuild at once or fix it. - - hasufell -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJQOpaJAAoJEFpvPKfnPDWzpI4H/igZDuVGyjdKEl9SvvV9gnY0 72esQTiHfx00gO42lOguutwBX54DV/S7HggEZy1P9UIi5gfJckrFKsM3Y9oD9tUX X9EZA6WEU3F90MD0gFFxH2jcoEbm85UfjJkEwI2Hy1+lEOPAZqzBV1F0sBE/Xd/U WwIgAHy8jKsTI1RTIW8r4VOoexifCllWvjbKiDNxeeixTQhwhvrCWnbqTI0WKR95 Er6LNwwYNh+Ugu7s6OwR7o3cUAuOXt3LUjf45bEGAgPF+lrqsXrfB9N5ANu+3177 94sxHgzYkRSsORjjl678/tZFfyp1jagX1FcT6O1dd/J4sHqfRdyZfy29d0DH/e0= =gCI5 -----END PGP SIGNATURE-----

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First five Tor tech reports
by Karsten Loesing 27 Aug '12

27 Aug '12

Hi Roger, hi Nick, here are the first five metrics tech reports that I'd like to turn into Tor tech reports (see #5405 for the idea behind this). If you agree that this is a good idea, I'll push the sources to tech-reports.git and put the PDFs on the Tor website. I need your confirmation for each report as part of the process, though. - https://people.torproject.org/~karsten/volatile/bridge-stability-2011-10-31… - https://people.torproject.org/~karsten/volatile/blocking-2011-09-15.pdf - https://people.torproject.org/~karsten/volatile/detector-2011-09-09.pdf - https://people.torproject.org/~karsten/volatile/relay-stability-2011-06-30.… - https://people.torproject.org/~karsten/volatile/data-2011-03-14.pdf Thanks, Karsten

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https://gitweb.torproject.org/check.git
by bgt56zhn＠Safe-mail.net 26 Aug '12

26 Aug '12

Where is the code powering check.torproject.org? There is https://gitweb.torproject.org/check.git, but the repo has no commits. Thanks

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an alternate MyFamily definition
by tagnaq 24 Aug '12

24 Aug '12

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Hi, when requesting a new group by feature for compass [1] (#6662 [2]) I discussed with Karsten about how to handle asynchronous/overlapping families: karsten: > Here's an example. Assume we have three relays: A, B, and C. These > relays state the following family relationships: > > A: A, B B: A, B, C C: B, C > > We require mutual agreement about being in the same family, so we > could either come up with family A, B or with family B, C. Which > one is correct? I proposed to go with family = A, B, C because there is a mutual agreement between A<->B and B<->C. A and C agreed to be in a family with B, and B agreed to be in a family with A and C. Such configurations can be found in the wild mostly due to incomplete MyFamily configurations on relays in big families. As every big relay operator knows configuring families is a non-trivial effort with a growing number of relays. Now I thought about it and wanted to suggest this MyFamily interpretation as an alternate approach to the fully mutual setup where *every* relay must be reconfigured as opposed to just two of them. Why? This would reduce the configuration effort required when adding a new relay to *two* relays regardless of how many relays are in your family. Now, the MyFamily configuration overhead for big families is a well known problem so I suppose someone else did already propose this approach? What do you think about it? [1] https://compass.torproject.org [2] https://trac.torproject.org/projects/tor/ticket/6662 a additional example to make this clearer: A: A, B, C B: A, B, C C: A, B, C D: A, B, C, D family = A, B, C A family member must have a *mutual* agreement with at least *one* node. -----BEGIN PGP SIGNATURE----- iF4EAREKAAYFAlA2YkoACgkQyM26BSNOM7Yp2wD/VTBw8BmUJlRZtIfXahIGX+t0 zwzP6MfRDwgPCsQMeEUA/3dUyyoq91Fx4lmihWHis2DZNAoM/CHh2MnwgMNL/W1W =FWRU -----END PGP SIGNATURE-----

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[GSoC] [Stegotorus] Pencil down
by vmon 23 Aug '12

23 Aug '12

Hey Zack, I just did my last pushes before putting my pencil down for the final evaluations. They take care of the followings: - The remaining of all your comments on the github. Except for "always use xalloc instead of new". I have used new extensively for instantiating objects. What's exactly about xalloc that's better than new, if you have overloaded both of them? - Documenting the http_apache steg protocol. The tl_oneway_c2s fails the http-proxy test. It still have problem with one-sided EOF. It used to pass when I allow the one way socket shutdown in the http proxy. So, I think stegotorus still have problem with EOF management. You might want to look at it when you have time. Happy moving! vmon

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Tor and NAT devices: increasing bridge & relay reachability or, enabling the use of NAT-PMP and UPnP by default.
by Jacob Appelbaum 22 Aug '12

22 Aug '12

Hi, My latest tech report is now up. I think it would be a nice idea if we could kick off a discussion about Tor, NAT devices and reachability. Tor and NAT devices: increasing bridge & relay reachability or, enabling the use of NAT-PMP and UPnP by default: https://research.torproject.org/techreports/tor-nat-plan-2012-08-22.pdf Feedback welcome and encouraged! All the best, Jake

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[ooniprobe-dev] Summary of OONI hackfest
by Arturo Filastò 22 Aug '12

22 Aug '12

We had a mini hackfest at noisebridge on OONI and this thread is to summarize what we discussed. mct: feel free to add things from your notes that are not detailed here. One of the problems that we mostly focused our attention on was how to detect censorship on HTTP when the user is presented with a block page. The reason for focusing on this is that censorship over HTTP is the most prevalent form. # Detecting censorship in web sites Detecting that the presented web page is not the expected site, but is a censorship page turns out to be a non trivial task, especially when you are dealing with web pages that have dynamic content. This problem is detailed in this trac ticket: https://trac.torproject.org/projects/tor/ticket/6180. We ended up dividing the possible approaches into two macro categories: Statistical and Heuristic [1] One of the properties we would like our classifier to have is that that a user should be able to detect that the presented page is the block page by just having a copy of OONI and some data that can be given to them over a non censored channel (sneakernet for example). ## DOMClass, a eigenvalue based statistical classifier What we ended up implementing is a classifier that considers the DOM structure of the web page. We can easily build such a database of the DOM structure features of the websites we are interested in analyzing and ship these to users. This is how the algorithm works: This classifier uses the DOM structure of a website to determine how similar the two sites are. The procedure we use is the following: * First we parse all the DOM tree of the web page and we build a list of TAG parent child relationships (ex. <html><a></a><c></c></html> => (html, a), (a, b), (html, c)). * We then use this information to build a matrix (M) where m[i][j] = P(of transitioning from tag[i] to tag[j]). If tag[i] does not exists P() = 0. Note: M is a square matrix that is number_of_tags wide. * We then calculate the eigenvectors (v_i) and eigenvalues (e) of M. * The corelation between page A and B is given via this formula: correlation = dot_product(e_A, e_B), where e_A and e_B are resepectively the eigenvalues for the probability matrix A and the probability matrix B. You will note that the Matrix we are computing eigenvalues for somewhat resembles a Markov model for transitions between DOM element X to Y. This algorithm appears to work pretty well even on highly dynamic web sites (such as the homepage of news.google.com) Problems with this algorithm: * It does not take into account the global position of DOM elements or how deeply nested they are. (<a><a></a></a> (a,b),(b,a),(a,b) is equivalent to <a><a></a></a><a></a> (a,b), (b,a), (a,b)) Looking into other possible solutions to this problem I took a look at algorithms that are used to compute graph similarity. This problem could be solved by using an algorithm that calculates the maximum isomorphic subgraph, but this problem is NP-hard. [2] I am unsure if the computation effort to use algorithms along these lines is worth while. I can't seem to find the notes on the rest of the discussion, perhaps mct will integrate with this discussion. - Art. [1] https://trac.torproject.org/projects/tor/ticket/6180#comment:3 [2] <http://en.wikipedia.org/wiki/Subgraph_isomorphism_problem>http://en.wikipedia.org/wiki/Maximum_common_subgraph_isomorphism_problem

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[GSoC] APAF Report
by Michele Orrù 21 Aug '12

21 Aug '12

Hello, As Daniel suggested, I'm writing this email to keep you updated on my Google Summer of Code Project - APAF. Following the hackathon of the 18-21 May, we reached a working build environment, and a primitive administration page. Below follows a brief update about what is the current status of the software: Development: I've defined what a service really is in terms of implementation, and approached the administration service (the "panel") in such a way that any future application may hide or completely override it. This shall give not only a comfortable user experience but also elasticity to the software. Testing: unittests cover most of the software, but even though APAF is still in an embrional state, I would be glad anyway to receive some feedbacks from you, about which OS the apaf was tested on and any bug you were able to find. Documentation: currently is disorganized, and splitted between sphynx and github wiki. But, the data is there, and I promise that on the next days I will merge/rewrite the two :) Anyway, the code is highly documented, in my opinion the generated sphynx documentation is acceptable. Deployment: I kept working on the build system, which at the current revision works on windows, osx and as vanilla python .egg., but there are still some issues - for example, the automation of .deb build and blobbing external tools on windows. In case you need a quick link to the project, https://github.com/mmaker/apaf -- ù

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