- tor-dev - lists.torproject.org

New Fallback Directory File Format
by teor 12 Jan '18

12 Jan '18

Hi all, Some time in the next few weeks, the Tor fallback directory mirror file format will change. This affects stem and Relay Search, which parse this file. Change Description Here is a list of changes to the file format: * the "weight" line has been removed, and replaced with a Tor config default (#24679, #24681) * the comma that separates fallback C strings is now on its own line * a "nickname" comment has been added (#24600) * an optional "extrainfo" comment has been added (#22759) The added fields will be populated with placeholders until the list is rebuilt (#22271). This will hopefully happen some time in the next few weeks. Requesting More Extra Info Caches There are only a few fallbacks that cache extra-info documents. I checked 67, and only 4 cached extra-info documents. atagar, do you want me to ask some fallback operators to set DownloadExtraInfo 1? What number or proportion would you like? (We allow approximately 25% of fallbacks to go down before we start to rebuild the list. In the worst case, this can mean that ~40% are down at some point.) Example Entries A sample entry in the new format, using actual relay info: "5.9.110.236:9030 orport=9001 id=0756B7CD4DFC8182BE23143FAC0642F515182CEB" " ipv6=[2a01:4f8:162:51e2::2]:9001" /* nickname=rueckgrat */ /* extrainfo=1 */ , The current fallback file in the new format, with placeholders: https://github.com/teor2345/tor/blob/ticket22759_tree/src/or/fallback_dirs.… A small sample fallback file in the new format, with actual relay info: https://trac.torproject.org/projects/tor/attachment/ticket/22759/fallback_d… Please let me know if you would like any changes to the format. T -- Tim Wilson-Brown (teor) teor2345 at gmail dot com PGP C855 6CED 5D90 A0C5 29F6 4D43 450C BA7F 968F 094B ricochet:ekmygaiu4rzgsk6n xmpp: teor at torproject dot org ------------------------------------------------------------------------

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Agnostic Tools: Code Dev and Support For
by grarpamp 12 Jan '18

12 Jan '18

> I'm interested in helping you guys with Tor development. I don't really care > what I work on, except I do not support .onion websites (though I am willing > to be convinced otherwise) so I would prefer not to participate directly in > their development. I have plenty of experience with writing code Folks in convo before have covered some of these areas and more that one could surely find or think of... Philosophical... Why does someone want to support and develop for Tor, or any other overlay p2p anonymity network, or crypto, for that matter? When even a fix to the manpage could be read and used by onion users and operators, same for metrics, lists, or any other part of the ecosystem. Does one fear "bad" things, association, or support "good" things? Does freespeech, anonymity, privacy, human rights sound "good"? What is "bad"? Censorship? Theft, Dictatorships, Police States, whether one's own, that of the Enemy, or that of the Oppressed? Cryptocurrency, anonymity, free markets, privacy, messaging... "bad"? "Good" [only] when used to defeat "bad" things inside or outside of [mal]functional democracies that assert majority force over minorities who have forced no one? Ricochet, Signal, GPG... "bad"? New technology that forces change over old entrenched ways... "bad"? Are anonymous forums where professional therapists give pro bono counseling to even the most reviled, depraved, criminal, socially scarlet lettered and outcast... "bad"? Materials and talk of religion? Are datamining, traffic archiving, exploits, cleartext... "good"? Tor has exits... do people realize how much of both what they like to "support", and abhor, travels over those exits? The variety of traffic there is no different than onions. Should exits be unsupported? What about the internet, or printing presses, should those tools be unsupported? Are they "bad", get their makers looked askew? Onions, exits, internet, presses, hammers... all simply agnostic tools. Tools can be used to build great things, to defend, or to wield in bloody murder. And what of biases over certain agnostic tools instead of over the separate "good" or "bad" uses of them? Do other tool builders and users have to wonder if their tools are being compromised by those with such biases? What of when those with biases end up needing the tools themselves, what will be the tool quality, or their ability to do "good" with them? Have people taken the time to explore the onion space to find and participate in all the "good" things they like therein, to create and grow them, or even engage in counsel and advocacy against the "bad"? What tools would be needed to do that? Yes, people are free to work on what they like... including giving deep thought as to what they like and don't, and why, and how supporting agnostic tools can actually fit with that. Are not your pens tools? Who likes those? Who supports those? What if they didn't? Pens... write code. Tech, fun, politic... Amounting to consideration feature X may prevent or diminish a better archictecture on balance for some higher importance feature Y. That should be covered open devops as usual. Or if the *technology* or *code* of eg: eepsites onions, or other subsets of various projects are not in their interest or knowledge practice area. Ok. Or if the features provided by any overlay network or tool are deemed flawed, and the technical or political effort to get them fixed, or rearchitecture, or correctly advertised, or called out within as bunk, is too high, therein it may be better to abandon them and or speak out freely as such.

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Volunteering for Tor
by Charles Hunt 12 Jan '18

12 Jan '18

After 15 years of desktop support, I am following my passion to be a Python3 programmer. I am still an amature programmer, but I aced the python fundamentals course from Coursera to flesh out my skills. I would like to continue developing my programming skills by volunteering for Tor. Do you have something I can help with? Thank you. Charles

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Re: [tor-dev] A suggestion for differential private statistics gathering
by Eyal Ronen 11 Jan '18

11 Jan '18

Hi Tim, First of all thanks for your detailed and quick response. I am sorry for my delayed response as I am attending Real World Crypto (BTW if there are any devs here it will be nice to try and meet). I will try to answer your questions and remarks below. >Hi Eyal, > >Thank you for letting us know about your research. > >You've emailed an internal discussion list, so I'm going to direct all >responses to the public tor-dev@ list. That is the list where we discuss >changes to Tor. > >Please see my response below: > >> On 7 Jan 2018, at 20:31, Eyal Ronen <eyal.ronen(a)weizmann.ac.il> wrote: >> >> I am a PHD student, and have just published online a paper, that shows a protocol that I think might be relevant to the TOR network. >> The protocol allows a server to privately learn information from a client, and is resilient to a situation where a malicious adversary wants to temper with the statistics. >> The main use case in our paper is learning popular passwords, > >Are you aware of this password list? >(It has no privacy apart from hashing the passwords, because the >passwords are already publicly available in data breaches.) > > https://www.troyhunt.com/introducing-306-million-freely-downloadable-<https://www.troyhunt.com/introducing-306-million-freely-downloadable-pwned-…> pwned<https://www.troyhunt.com/introducing-306-million-freely-downloadable-pwned-…> -passwords/<https://www.troyhunt.com/introducing-306-million-freely-downloadable-pwned-…> One of the assumptions of our paper is that if we blacklist known vulnerable passwords, we will change the passwords distribution and new passwords will become "popular". We enable the server to continually learn the changing password distribution. Another example is that the previously popular password "superman" might be replaced today with the password "wonderwoman", and we want to be able to learn this kind of changes. > >> but we believe that it might also be usable for other cases in the TOR network. As we do not know the needs and challenges in the TOR network, we would greatly appreciate any feedback from the TOR metrics community. > >I would be interested in an explanation of the tradeoffs between the >16 and 32 bit versions of the protocol. In particular, we may not be >able to provide servers with 4 GB of RAM for the 32 bit protocol. > >What would we lose with a 16 bit version? Is a 24 bit version possible? Any bit number is possible , and without any impact on security. The number of bit is the size of the domain or histogram of items you want to measure. If you use a low number of bits, you can have collision between different measured values, that may change the statistics. For example, lets assume we want to find out popular sites in the TOR network. We encode the sites IP. If you use 32 bit version, you can measure each IP individually. Otherwise you use a truncated a hash of the IP address. Now when you find a heavy hitter, you know what possible IP contributed to this measurement. But you can't know which one or more IP addresses are the popular ones. However I believe that this might not be a problem. One of the main differences to other solutions is that we work in the "Local model" and do no require any "Tally Reporters" to protect the data or for answers to be aggregate on the relay servers. The only place that needs to store the whole histogram is the one server that aggregates all of the information. I think that it greatly reduce the communication and implementation overheads of the solution. I think that the main differences are the one above and our provable malicious resilient. There are other differences but I think that this is the most relevant one. If we don't care about malicious users or relays we can use the semi honest version, that takes have almost zero computation requirements, and can be done either by the user, or by the relay. If we want to use the malicious resilient, it is a bit more costly, and we need to think of the right way and place to incorporate it. If it sounds interesting I will like to find a possible use case that I can try and design the best tailored solution for you. And we can try to prove the security and complexity of the solution, and verify this with safety board. If needed I have a POC written in Python to be easily understandable, but I can easily implement it using TOR's cryptographic package of choice. I will also try to go over the current proposal on the other papers in more details. Thanks again, Eyal Ronen > >> The paper is titles "How to (not) share a password: Privacy preserving protocols for finding heavy hitters with adversarial behavior" and can be found at https://eprint.iacr.org/2018/003 >> >> The abstract is: >> "Bad choices of passwords were and are a pervasive problem. Most password alternatives (such as two-factor authentication) may increase cost and arguably hurt the usability of the system. This is of special significance for low cost IoT devices. >> >> Users choosing weak passwords do not only compromise themselves, but the whole eco system. For example, common and default passwords in IoT devices were exploited by hackers to create botnets and mount severe attacks on large Internet services, such as the Mirai botnet DDoS attack. >> >> We present a method to help protect the Internet from such large scale attacks. We enable a server to identify popular passwords (heavy hitters), and publish a list of over-popular passwords that must be avoided. This filter ensures that no single password can be used to comprise a large percentage of the users. The list is dynamic and can be changed as new users are added or when current users change their passwords. We apply maliciously secure two-party computation and differential privacy to protect the users' password privacy. Our solution does not require extra hardware or cost, and is transparent to the user. >> >> The construction is secure even against a malicious coalition of devices which tries to manipulate the protocol in order to hide the popularity of some password that the attacker is exploiting. We show a proof-of-concept implementation and analyze its performance. >> >> Our construction can also be used in any setting where one would desire to privately learn heavy hitters in the presence of an active malicious adversary. For example, learning the most popular sites accessed by the TOR network." > >Tor Proposals > >There is a current proposal to add privacy-preserving statistics to Tor >using a scheme that's based on PrivCount: > > https://gitweb.torproject.org/torspec.git/tree/proposals/288-<https://gitweb.torproject.org/torspec.git/tree/proposals/288-privcount-with…> privcount<https://gitweb.torproject.org/torspec.git/tree/proposals/288-privcount-with…> -with-shamir.txt<https://gitweb.torproject.org/torspec.git/tree/proposals/288-privcount-with…> > >PrivCount is limited to counters with integer increments, so we can't >easily find the most popular site (the mode), or calculate the median. > >We discussed the proposal on tor-dev@, and decided that we could add >more sophisticated statistics later. We would appreciate your feedback >on the proposal. In particular, please let us know if there is anything >we should change in the proposal to make it easier to extend with schemes >like yours in future. > >Here is the proposal thread: > > https://lists.torproject.org/<https://lists.torproject.org/pipermail/tor-dev/2017-December/012699.html>pipermail<https://lists.torproject.org/pipermail/tor-dev/2017-December/012699.html>/tor-dev/2017-December/012699.html<https://lists.torproject.org/pipermail/tor-dev/2017-December/012699.html> > > >Anyone is welcome to submit Tor proposals, the process is described here: > > https://gitweb.torproject.org/torspec.git/tree/proposals/001-process.txt > > >Related Research > >There was a paper at CCS 2017 that sounds very similar to your scheme: > >Ellis Fenske, Akshaya Mani, Aaron Johnson, and Micah Sherr. Distributed >Measurement with Private Set-Union Cardinality. In ACM Conference on >Computer and Communications Security (CCS), November 2017. > >Source: http://safecounting.com/ > >Can you explain how your scheme differs from PSC? > > >There's a forthcoming paper at NDSS 2018 that measures a single onion >site's popularity with differential privacy using PrivCount: > >Inside Job: Applying Traffic Analysis to Measure Tor from Within >25th Symposium on Network and Distributed System Security (NDSS 2018) >Rob Jansen, Marc Juarez, Rafael Galvez, Tariq Elahi, and Claudia Diaz > >Source: https://onionpop.github.io/ > >But the measurement was limited to one site, because PrivCount can't >calculate the modal value from set of samples. So I can see the >advantages of a scheme like yours over PrivCount. > > >Your Own Research > >And finally, if you do want to do research on the public Tor network, I >would recommend contacting the Tor Research Safety Board for advice: > > https://research.torproject.org/safetyboard.html > >T > >-- >Tim Wilson-Brown (teor) Best regards, Eyal

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Re: [tor-dev] Public Key Chaos
by thomas.hluchnik＠netcologne.de 11 Jan '18

11 Jan '18

Am Wednesday 10 January 2018 17:37:57 schrieb Azat Khuzhin: > Nick suggested me to upload my key to repo (github), to make people know > that at least I have admin rights to that repo. > > But now I remembered, that my github account has attached gpg key to it, > you can see it here: > https://github.com/libevent/libevent/releases/tag/release-2.1.8-stable > > Does this enough for your needs? No, not really. Let's assume, an evil 3rd party is redirecting my download (by DNS spoofing or that), using a fake web server certificate. This would enable the attacker to exchange the libevent package + the checksum files + signature file. This fake signing key could be uploaded to the key servers by them, pretending it were your personal key. If I would trust in that, the tor network would be in danger. TOR executables would rely on insecure shared libraries. The only way for establishing trust is: the signature must be created with a GPG key which was signed by other trustworthy persons. For example, Nick's key is signed by many people since many years. So I have no doubt that files which are signed with that key are really from Nick. If he signs your key, then I can trust in files, signed with your key. If you are going to sign more packages in the future, don't hesitate to collect further signatures from other trustworthy persons or organizations. Best Regards, Thomas Hluchnik

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Block Global Active Adversary Cloudflare
by debug 11 Jan '18

11 Jan '18

Is there any specific reason why there is no comment from Tor-team for this issue? https://trac.torproject.org/projects/tor/ticket/24351

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Tor dev help
by Beastr0 11 Jan '18

11 Jan '18

Hey guys, For the time being I would prefer to not have my real name attached to Tor so I hope you don't mind if I introduce myself as Beastro. I love Tor and its mission. I was wondering if you guys had any projects that I could help out with? I can write code in python, java, C and also have plenty of experience with plenty other languages. As a student, I don't have a ton of time, so I can only spend maybe an hour or two a day helping out. Let me know if there's anything I can do! Best, - Beastro Sent with [ProtonMail](https://protonmail.com) Secure Email.

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Why do DirAuths take that long to update a relay's version information?
by nusenu 11 Jan '18

11 Jan '18

Hi, the goal of this email is to avoid a false positive warning for relay operators on atlas but the root cause might be in core tor. background: I really liked when irl added the big red warning to atlas when a tor relay runs an outdated (aka not running a "recommended") tor version because it actually triggered operators to upgrade, an important step toward a more healthy network. The problem is: This big red banner on atlas has false-positives which confuses operators [0]. Originally this has been an onionoo bug which has been fixed in v1.8.0, but it happens again and Karsten had the feeling that tor dir auths do not update the version information of a relay after it upgraded (and uploaded a new descriptor). I looked into one example and can confirm what Karsten suggested [1]. Let me show you that example of FP 1283EBDEEC2B9D745F1E7FBE83407655B984FD66. Data has been provided by Karsten and is available here: [2]. That relay was running 0.3.0.10 and upgraded to 0.3.0.13 and uploaded his first descriptor with 0.3.0.13 on: 2018-01-09 10:14:00,server,,0.3.0.13 except for bastet dir auths did not care and still said this relay runs 0.3.0.10: 2018-01-09 11:00:00,consensus,,0.3.0.10 2018-01-09 11:00:00,vote,bastet,0.3.0.13 <<<< note 2018-01-09 11:00:00,vote,dannenberg,0.3.0.10 2018-01-09 11:00:00,vote,dizum,0.3.0.10 2018-01-09 11:00:00,vote,Faravahar,0.3.0.10 2018-01-09 11:00:00,vote,gabelmoo,0.3.0.10 2018-01-09 11:00:00,vote,longclaw,0.3.0.10 2018-01-09 11:00:00,vote,maatuska,0.3.0.10 2018-01-09 11:00:00,vote,moria1,0.3.0.10 2018-01-09 11:00:00,vote,tor26,0.3.0.10 2018-01-09 12:00:00,consensus,,0.3.0.10 2018-01-09 12:00:00,vote,bastet,0.3.0.13 <<<<<< 2018-01-09 12:00:00,vote,dannenberg,0.3.0.10 2018-01-09 12:00:00,vote,dizum,0.3.0.10 2018-01-09 12:00:00,vote,Faravahar,0.3.0.10 2018-01-09 12:00:00,vote,gabelmoo,0.3.0.10 2018-01-09 12:00:00,vote,longclaw,0.3.0.10 2018-01-09 12:00:00,vote,maatuska,0.3.0.10 2018-01-09 12:00:00,vote,moria1,0.3.0.10 2018-01-09 12:00:00,vote,tor26,0.3.0.10 even 6 hours later this is unchanged. Then the operator upgraded from 0.3.0.13 to 0.3.1.9 and uploaded his first descriptor: 2018-01-09 16:39:01,server,,0.3.1.9 this remained "unnoticed" by all dir auths until longclaw voted for the new version: 2018-01-09 23:00:00,consensus,,0.3.0.10 2018-01-09 23:00:00,vote,bastet,0.3.0.10 2018-01-09 23:00:00,vote,dannenberg,0.3.0.10 2018-01-09 23:00:00,vote,dizum,0.3.0.10 2018-01-09 23:00:00,vote,Faravahar,0.3.0.10 2018-01-09 23:00:00,vote,gabelmoo,0.3.0.10 2018-01-09 23:00:00,vote,longclaw,0.3.1.9 <<<<< 2018-01-09 23:00:00,vote,maatuska,0.3.0.10 2018-01-09 23:00:00,vote,moria1,0.3.0.10 2018-01-09 23:00:00,vote,tor26,0.3.0.10 On 2018-01-10 02:38:07 the relay uploaded a second descriptor with v0.3.1.9 and almost all dir auths agreed immediately: 2018-01-10 02:38:07,server,,0.3.1.9 2018-01-10 03:00:00,consensus,,0.3.1.9 2018-01-10 03:00:00,vote,bastet,0.3.0.10 2018-01-10 03:00:00,vote,dannenberg,0.3.1.9 2018-01-10 03:00:00,vote,dizum,0.3.1.9 2018-01-10 03:00:00,vote,Faravahar,0.3.1.9 2018-01-10 03:00:00,vote,gabelmoo,0.3.1.9 2018-01-10 03:00:00,vote,longclaw,0.3.1.9 2018-01-10 03:00:00,vote,maatuska,0.3.1.9 2018-01-10 03:00:00,vote,moria1,0.3.1.9 2018-01-10 03:00:00,vote,tor26,0.3.1.9 So it took the operator 17 hours to convince enough dir auths that he upgraded. I can see multiple reasons why this can make sense (as the tor version is actually not that relevant consensus data) but maybe it was not clear what the side effects of not updating that field are. While I believe there is still another onionoo issue, this should also be improved. Thoughts? [0] http://lists.nycbug.org/pipermail/tor-bsd/2018-January/000620.html [1] https://trac.torproject.org/projects/tor/ticket/22488#comment:11 [2] https://trac.torproject.org/projects/tor/attachment/ticket/22488/task-22488… -- https://mastodon.social/@nusenu twitter: @nusenu_

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prop279 global wildcard '*' exploits
by nullius 10 Jan '18

10 Jan '18

At https://trac.torproject.org/projects/tor/ticket/24774#comment:5 , nickm stated: >I'm not sure that the sandboxing section is necessary. We should say >that _all_ plugins should only access the network over Tor, unless they >are using some comparably strong anonymity mechanism. [...] In reply https://trac.torproject.org/projects/tor/ticket/24774#comment:6 , I ask: >The proposal as written states under §3.2, specifically discussing >`'*'`: > >>Perhaps we trust the name plugin itself, but maybe the name system >>network could exploit this? > >What does this mean? Is there any specific information on what >potential exploits the spec authors have thought of? '''Would >requiring Tor-only connections prevent these potential exploits?''' I >should ask on `tor-dev`. Per the discussion in the current version of the spec (686aaf1), there is concern that a '*' plugin may try to resolve ordinary DNS names. But this separate, quoted statement assumes a trustworthy plugin, which I take to mean that it would not grab .com, etc. So, what was the concern behind that statement? (And are there any other potential exploits, which may or may not be prevented by requiring name resolution through Tor?) -- nullius(a)nym.zone | PGP ECC: 0xC2E91CD74A4C57A105F6C21B5A00591B2F307E0C Bitcoin: bc1qcash96s5jqppzsp8hy8swkggf7f6agex98an7h | (Segwit nested: 3NULL3ZCUXr7RDLxXeLPDMZDZYxuaYkCnG) (PGP RSA: 0x36EBB4AB699A10EE) “‘If you’re not doing anything wrong, you have nothing to hide.’ No! Because I do nothing wrong, I have nothing to show.” — nullius

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Public Key Chaos
by thomas.hluchnik＠netcologne.de 10 Jan '18

10 Jan '18

Hello all, I am just going to update my tor server, building packages from source. I do that not only for tor but also for libevent. So I downloaded the tarballs plus signature from libevent.org and that's what I found: $ gpg --verify libevent-2.0.22-stable.tar.gz.asc gpg: Signature made Mon Jan 5 16:16:20 2015 CET using RSA key ID 8D29319A gpg: Good signature from "Nick Mathewson <nickm(a)alum.mit.edu>" gpg: aka "Nick Mathewson <nickm(a)wangafu.net>" gpg: aka "Nick Mathewson <nickm(a)freehaven.net>" gpg: aka "[jpeg image of size 3369]" $ gpg --verify libevent-2.1.8-stable.tar.gz.asc gpg: Signature made Sun Jan 29 19:42:03 2017 CET using RSA key ID 8EF8686D gpg: Good signature from "Azat Khuzhin <a3at.mail(a)gmail.com>" gpg: WARNING: This key is not certified with a trusted signature! gpg: There is no indication that the signature belongs to the owner. Primary key fingerprint: 9E3A C83A 2797 4B84 D1B3 401D B860 8684 8EF8 686D $ gpg --list-sigs "Azat Khuzhin" pub 2048R/8EF8686D 2010-06-10 uid Azat Khuzhin <a3at.mail(a)gmail.com> sig 3 8EF8686D 2010-06-10 Azat Khuzhin <a3at.mail(a)gmail.com> sub 2048R/7A34F923 2010-06-10 sig 8EF8686D 2010-06-10 Azat Khuzhin <a3at.mail(a)gmail.com> While nickm(a)alum.mit.edu was signed by many, many people, I find no signature for "Azat Khuzhin <a3at.mail(a)gmail.com>" at all. How can I trust that key? How can I be sure that libevent 2.1.8 is a good package? Why has Azat Khuzhin public key no signature from Nick Mathewson or anyone else? I don't trust that package for now until I find it signed with the keys of at least Nick Mathewson and Niels Provos. Correct me if I a wrong. Best Regards, Thomas

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