March 2015 - tor-dev - lists.torproject.org

#if 0 unused functions?
by Sebastian Hahn 23 Mar '15

23 Mar '15

Hi there, we have some functions which we never call anywhere. In many cases, it appears we shouldn't delete them from the source because they "belong" there - the thing I initially stumbled across was ed25519_seckey_write_to_file(), for example. But I also don't see why compiling it and potentially including it in our binary makes any sense. Thoughts? Cheers Sebastian

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Re: [tor-dev] #if 0 unused functions?
by teor 22 Mar '15

22 Mar '15

> Date: Sun, 22 Mar 2015 05:12:03 +0100 > From: Sebastian Hahn <sebastian(a)torproject.org> > To: tor-dev(a)lists.torproject.org > > Hi there, > > we have some functions which we never call anywhere. In many cases, it > appears we shouldn't delete them from the source because they "belong" > there - the thing I initially stumbled across was > ed25519_seckey_write_to_file(), for example. But I also don't see why > compiling it and potentially including it in our binary makes any sense. > > Thoughts? > > Cheers > Sebastian I'm think that removing / disabling unused code is a great idea, but I wonder what happens over the long term: [How] do we prevent bit-rot on the disabled code? Does the disabled code have unit tests? Should we add unit tests or keep them active to prevent bit-rot? Or should any unit tests be disabled too? I wonder if we could unit test unused code, but not link it into the tor binary. This would make sure it works if we ever want to use it in future, but without the risks and performance impacts of including unused code in the binary. There could be issues with this strategy that I haven't thought of. Like the added maintenance cost involved in keeping unused code and unit tests up-to-date. Perhaps we could: * remove entirely if we're unlikely to ever use the code, * disable if we want to keep it around for future reference, and * unit test it, but not link it in to the tor binary, if we think we'll use it soon. Which category do most of the unused functions fall into? teor teor2345 at gmail dot com pgp 0xABFED1AC https://gist.github.com/teor2345/d033b8ce0a99adbc89c5 teor at blah dot im OTR C3C57B23 349825DE 929A1DEF C3531C25 A32287ED

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Directory Server Consensus Status Flag
by Matthew Finkel 22 Mar '15

22 Mar '15

Hi all, I'd like some opinions. Currently authorities give relays the V2Dir if they are useful directory servers. Clients don't actually care about this flag in any way, but it's a useful visual indicator. With proposal 237 (All relays are directory servers) and #12538 as its implementation, the current plan is to continue using the V2Dir flag, but now clients will actually care if a relay has the V2Dir flag and choose directory servers based on it. Tickets #11103 and #1338 actually wanted to get rid of the V2Dir flag, for good reasons. If we're going to rename the flag, we should do it before #12538 is merged, and probably make the change in the same branch. The V2Dir flag needlessly specifies an unuseful protocol version. #1338 suggested switching to a V3Dir flag, but it was decided this was not such a good idea. Proposal 185 chose a "DirCache" Consensus flag. I think either "DirServer" or "DirCache" are good choices for this, but DirServer is more in line with the wording used in Prop 237. Are there any objections to changing the name of the flag? (There will be another email in a few minutes with an updated version of prop 237.) Thanks! Matt

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Call for a big fast bridge (to be the meek backend)
by David Fifield 21 Mar '15

21 Mar '15

The meek pluggable transport is currently running on the bridge I run, which also happens to be the backend bridge for flash proxy. I'd like to move it to a fast relay run by an experienced operator. I want to do this both to diffuse trust, so that I don't run all the infrastructure, and because my bridge is not especially fast and I'm not especially adept at performance tuning. All you will need to do is run the meek-server program, add some lines to your torrc, and update the software when I ask you to. The more CPU, memory, and bandwidth you have, the better, though at this point usage is low enough that you won't even notice it if you are already running a fast relay. I think it will help if your bridge is located in the U.S., because that reduces latency from Google App Engine. The meek-server plugin is basically just a little web server: https://gitweb.torproject.org/pluggable-transports/meek.git/tree/HEAD:/meek… Since meek works differently than obfs3, for example, it doesn't help us to have hundreds of medium-fast bridges. We need one (or maybe two or three) big fat fast relays, because all the traffic that is bounced through App Engine or Amazon will be pointed at it. My PGP key is at https://www.bamsoftware.com/david/david.asc if you want to talk about it. David Fifield

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Re: [tor-dev] Fwd: [guardian-dev] Orbot v15 alpha 5 is out: MeekObfs4VPNQRCodez!
by Nathan Freitas 20 Mar '15

20 Mar '15

On Fri, Mar 20, 2015, at 04:05 AM, isis wrote: > Nathan Freitas transcribed 0.8K bytes: > > On Thu, Mar 19, 2015, at 06:58 PM, David Fifield wrote: > > > What would it take to get some screenshots that show how to turn on > > > pluggable transports? I would like to add a guide to > > > https://trac.torproject.org/projects/tor/wiki/doc/meek#Quickstart and > > > instructions to > > > https://trac.torproject.org/projects/tor/wiki/doc/PluggableTransports#Howto… > > > . > > > > > > Or do you have such a guide I can just link to? > > > > > > > We're still finalizing the UI for the new features (QR code scanning, > > meek bridge type selection, etc) so once that is completed, we'll do a > > round of screenshots, guide updates, etc. This will most likely happen > > in early April. > > Wow, this is awesome! Great work, to all of you! > > Let me know if there's anything more I can do to help. In thinking about how users on phones/tablets will actually get obfs3/4/scramblesuit bridges, I realized that going to https://bridges.torproject.org on their mobile device will not be a great experience. The QR code scanning if they or a friend also has a PC, but in a pure mobile environment, it doesn't help so much. I can create a ticket for this, but just to lay out the idea, I think we need to have the bridge:// (or the improved proposed obfs4:// obfs3:// type specific scheme URLs) as a clickable link in both the bridges.tp.o site and the gettor email response messages. +n

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Remove "*" from pluggable transports spec?
by David Fifield 20 Mar '15

20 Mar '15

I was going to write an email advocating for the removal of the wildcard '*' transport specification in pt-spec.txt. But then I saw that the current version of the spec doesn't mention the wildcard anymore; it was replace with a TODO in https://gitweb.torproject.org/torspec.git/commit/pt-spec.txt?id=4dcd7e94f17… "TODO: Document '*' transport" So how about we remove the TODO and just act like it never existed? Normally tor tells the transport plugin what transports to activate by giving it a string like "obfs3,obfs4"; but you're supposed to also be able to pass "*", which means "activate all transports you are capable of." Apparently this feature, though pyptlib and goptlib support it, has never been implemented in tor itself: Implement the wildcard "*" protocol in {Client,Server}TransportPlugin lines https://trac.torproject.org/projects/tor/ticket/3725 A wildcard specification doesn't really make sense, anyway. For one example, flashproxy-client knows two transport names, "flashproxy" and "websocket", which are synonyms. But if tor asks for "*", flashproxy-client shouldn't open up two listeners. Another case is fog (a dynamic transport combiner), which constructs a chain of transports from a transport name like "obfs3_websocket". The transports can be combined in infinite ways; it doesn't make sense to say, "activate all of them." https://lists.torproject.org/pipermail/tor-dev/2013-December/005966.html Let's just drop this part of the spec, and delete some underspecified and unused code? David Fifield

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Re: [tor-dev] Fwd: [guardian-dev] Orbot v15 alpha 5 is out: MeekObfs4VPNQRCodez!
by Nathan Freitas 20 Mar '15

20 Mar '15

On Thu, Mar 19, 2015, at 06:58 PM, David Fifield wrote: > What would it take to get some screenshots that show how to turn on > pluggable transports? I would like to add a guide to > https://trac.torproject.org/projects/tor/wiki/doc/meek#Quickstart and > instructions to > https://trac.torproject.org/projects/tor/wiki/doc/PluggableTransports#Howto… > . > > Or do you have such a guide I can just link to? > We're still finalizing the UI for the new features (QR code scanning, meek bridge type selection, etc) so once that is completed, we'll do a round of screenshots, guide updates, etc. This will most likely happen in early April.

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thanks redditt
by Tyrano Sauro 20 Mar '15

20 Mar '15

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Fwd: [guardian-dev] Orbot v15 alpha 5 is out: MeekObfs4VPNQRCodez!
by Nathan Freitas 19 Mar '15

19 Mar '15

----- Original message ----- From: Nathan of Guardian <nathan(a)guardianproject.info> To: guardian-dev(a)lists.mayfirst.org Subject: [guardian-dev] Orbot v15 alpha 5 is out: MeekObfs4VPNQRCodez! Date: Thu, 19 Mar 2015 11:12:59 -0400 Orbot v15 alpha work is nearly done... APK: https://guardianproject.info/releases/Orbot-v15.0.0-ALPHA-5.apk SIG: https://guardianproject.info/releases/Orbot-v15.0.0-ALPHA-5.apk.asc Highlights: * Updated to tor-0.2.6.4-RC * VPN / full device "Apps" mode is fully implemented and stable - no root needed to run all apps on your device through Tor * Meek and Obfs4 pluggable transports are now included and working quite well, even with the VPN mode * Easy scanning and sharing of bridge address QR codes from bridges.torproject.org * Removed integrated webview/webkit for now, since Android WebView is generally p0wn3d More at: https://gitweb.torproject.org/n8fr8/orbot.git/tree/CHANGELOG Thanks to nickm, isis, yawning, fifield, sandro, team psiphon and many others for all the various amazing pieces coming together to make Orbot v15 a very important and big release. +n -- Nathan of Guardian nathan(a)guardianproject.info _______________________________________________ List info: https://lists.mayfirst.org/mailman/listinfo/guardian-dev To unsubscribe, email: guardian-dev-unsubscribe(a)lists.mayfirst.org

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Performance and Security Improvements for Tor: A Survey
by Ian Goldberg 19 Mar '15

19 Mar '15

As I mentioned at the dev meeting, Mashael and I were just finishing up a survey paper on Tor performance and security research. The tech report version was just posted on eprint: https://eprint.iacr.org/2015/235 for your perusing pleasure. ;-) Thanks, - Ian

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