December 2018 - tor-dev - lists.torproject.org

the consequences of deprecating debian alpha repos with every new major branch
by nusenu 21 Dec '21

21 Dec '21

Hi, tldr: - more outdated relays (that is a claim I'm making and you could easily proof me wrong by recreating the 0.3.3.x alpha repos and ship 0.3.3.7 in them and see how things evolve after a week or so) - more work for the tpo website maintainer - less happy relay operators [3][4] - more work for repo maintainers? (since a new repo needs to be created) When the tor 0.3.4 alpha repos (deb.torproject.org) first appeared on 2018-05-23 I was about to submit a PR for the website to include it in the sources.list generator [1] on tpo but didn't do it because I wanted to wait for a previous PR to be merged first. The outstanding PR got merged eventually (2018-06-28) but I still did not submit a PR to update the repo generator for 0.3.4.x nonetheless and here is why. Recently I was wondering why are there so many relays running tor version 0.3.3.5-rc? (see OrNetStats or Relay Search) (> 3.2% CW fraction) Then I realized that this was the last version the tor-experimental-0.3.3.x-* repos were shipping before they got abandoned due to the new 0.3.4.x-* repos (I can no longer verify it since they got removed by now). Peter made it clear in the past that the current way to have per-major-version debian alpha repos (i.e. tor-experimental-0.3.4.x-jessie) will not change [2]: > If you can't be bothered to change your sources.list once or twice a > year, then you probably should be running stable. but maybe someone else would be willing to invoke a "ln" commands everytime a new new alpha repo is born. tor-alpha-jessie -> tor-experimental-0.3.4.x-jessie once 0.3.5.x repos are created the link would point to tor-alpha-jessie -> tor-experimental-0.3.5.x-jessie It is my opinion that this will help reduce the amount of relays running outdated versions of tor. It will certainly avoid having to update the tpo website, which isn't a big task and could probably be automated but it isn't done currently. "..but that would cause relay operators to jump from i.e. 0.3.3.x to 0.3.4.x alphas (and break setups)!" Yes, and I think that is better than relays stuck on an older version because the former repo no longer exists and operators still can choose the old repos which will not jump to newer major versions. [1] https://www.torproject.org/docs/debian.html.en#ubuntu [2] https://trac.torproject.org/projects/tor/ticket/14997#comment:3 [3] https://lists.torproject.org/pipermail/tor-relays/2018-June/015549.html [4] https://trac.torproject.org/projects/tor/ticket/26474 -- https://twitter.com/nusenu_ https://mastodon.social/@nusenu

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DNS-over-HTTPS (DOH) in Firefox/Torbrowser
by nusenu 01 Jul '20

01 Jul '20

Hi, since Mozilla did tests [0] on DOH [1] in Firefox I was wondering if Torbrowser developers have put any thought into that as well? Note: I'm _not_ suggesting to use DOH in torbrowser I'm just asking because the answer probably matters for exit documentation in the relay guide if clients do DNS themselves over TCP connections instead of relying on the exit (even if torbrowser is not the only tor client). thanks, nusenu [0] https://www.ghacks.net/2018/03/20/firefox-dns-over-https-and-a-worrying-shi… [1] https://datatracker.ietf.org/doc/draft-hoffman-dns-over-https/ -- https://mastodon.social/@nusenu twitter: @nusenu_

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Lets give every circuit its own exit IP?
by nusenu 18 Mar '20

18 Mar '20

The unbearable situation with Google's reCAPTCHA motivated this email (but it is not limited to this specific case). This idea came up when seeing a similar functionality in unbound (which has it for a different reason). Assumption: There are systems that block some tor exit IP addresses (most likely the bigger once), but they are not blocked due to the fact that they are tor exits. It just occurred that the IP got flagged because of "automated / malicious" requests and IP reputation systems. What if every circuit had its "own" IP address at the exit relay to avoid causing collateral damage to all users of the exit if one was bad? (until the exit runs out of IPs and starts to recycle previously used IPs again) The goal is to avoid accumulating a bad "reputation" for the single used exit IP address that affects all tor users of that exit. Instead of doing it on the circuit level you could do it based on time. Change the exit IP every 5 minutes (but do _not_ change the exit IPs for _existing_ circuits even if they live longer than 5 minutes). Yes, no one has that many IPv4 addresses but with the increasing availability of IPv6 at exits and destinations, this could be feasible to a certain extend, depending on how many IPv6 addresses the exit operator has. There are exit operators that have entire /48 IPv6 blocks. problems: - will not solve anything since reputation will shift to netblocks as well (How big of a netblock are you willing to block?) - you can tell two tor users easily apart from each other even if they use the same exit (or more generally: you can tell circuits apart). There might be all kinds of bad implications that I'm not thinking off right now. - check.tpo would no longer be feasible - how can do we still provide the list of exit IPs for easy blocking? Exits could signal their used netblock via their descriptor. What if they don't? (that in turn opens new kinds of attacks where an exit claims to be /0 and the target effectively blocks everything) - more state to track and store at the exit -... some random thoughts, nusenu -- https://mastodon.social/@nusenu twitter: @nusenu_

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#3600 tech doc
by Richard Pospesel 13 Mar '19

13 Mar '19

Hey y'all, For the past little while I've been working on a technical overview doc for #3600 (Prevent redirects from transmitting+storing cookies+identifiers) detailing the problems, scenarios and possible solutions. Please take a look and feel free to comment, edit or add! Link: https://storm.torproject.org/grain/X4nhdNqR9fGRc7sgTefFkg/ best, -Richard

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Upcoming Tor change with application impact: "Dormant Mode"
by Nick Mathewson 04 Jan '19

04 Jan '19

Hello! This email is about a new feature that has some implications here for applications that use Tor. I want to make sure we've thought about and prepared for those implications, since we still have time to tweak this feature. == Overview In 0.4.0.x, Tor will begin supporting a new "dormant" mode in which it does not initiate network activity, and tries to avoid CPU wakeups. This mode is intended to help mobile devices sleep, and to minimize the impact of unused Tor clients on the network, and on the devices that run them. For the implementation history, see: https://trac.torproject.org/projects/tor/ticket/28335 and https://trac.torproject.org/projects/tor/ticket/28624 By default, Tor will become dormant if it is a pure client (not a relay, not an onion service[*]), and if it has received not client activity for 24 hours. (You can change the interval with DormantClientTimeout.) Unlike "DisableNetwork 1", Tor in dormant mode will not close any listener ports, and will become active again as soon as it receives a client connection. But like a "DisableNetwork 1" Tor, a dormant Tor will not build predicted circuits, and will not download directory information -- and therefore, will not bootstrap. Controllers can make Tor become dormant or non-dormant by sending the commands "SIGNAL DORMANT" and "SIGNAL ACTIVE" respectively -- these are now documented in control-spec.txt. Dormant state is persistent: if Tor has been idle for 20 hours, and you stop tor and start it again, and idle for 4 more hours, Tor will become dormant. If you stop tor and start it again, Tor will start in dormant mode. == Documentation Here's the documentation we have so far -- please let me know if you have ideas for clarification: DormantClientTimeout N minutes|hours|days|weeks If Tor spends this much time without any client activity, enter a dormant state where automatic circuits are not built, and directory information is not fetched. Does not affect servers or onion services. Must be at least 10 minutes. (Default: 24 hours) DormantTimeoutDisabledByIdleStreams 0|1 If true, then any open client stream (even one not reading or writing) counts as client activity for the purpose of DormantClientTimeout. If false, then only network activity counts. (Default: 1) DormantOnFirstStartup 0|1 If true, then the first time Tor starts up with a fresh DataDirectory, it starts in dormant mode, and takes no actions until the user has made a request. (This mode is recommended if installing a Tor client for a user who might not actually use it.) If false, Tor bootstraps the first time it is started, whether it sees a user request or not. After the first time Tor starts, it begins in dormant mode if it was dormant before, and not otherwise. (Default: 0) == Compatibility issues I see two issues here: one minor, and one major. Minor issue: some applications periodically make requests to the tor network on their own -- for example, Tor Browser's update requests. These requests prevent Tor from becoming dormant. If this is undesired, we can add some way around this. Major issue: some applications expect that Tor will always bootstrap when it starts, and delay presenting their own UI until Tor is ready. But if Tor starts as dormant, then it will not bootstrap until it receives a request from the client or a "SIGNAL ACTIVE" command from the controller. This could lead to breakage as the application waits for Tor to tell it that it's ready, and Tor waits for somebody to tell it that it's needed. Are all application developers okay with the issues above, and okay with working around them? If not, we may need changes in Tor before 0.4.0.x is released. Let's talk! [*] I'd like to add support for dormant onion services, but that's harder. See https://trac.torproject.org/projects/tor/ticket/28424 . peace, -- Nick

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Queries regarding Summer of Privacy 2019
by Pranav Vardia 04 Jan '19

04 Jan '19

Hi, I am Pranav Vardia , third year student from International Institute of Information Technology, Bangalore. I am writing this mail to clarify few of my queries regarding Summer of Privacy. Firstly, I would like to ask that is there a list of projects whcih we can work on or do we need to come up with our own proposal ? Secondly, I cannot find any timeline and project lists for previous years Summer of Privacy. It would be great if you could provide me links to the aforementioned. Regards, Pranav Vardia

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HTTPS and Tor Onion v3 Services
by Nathaniel Suchy 28 Dec '18

28 Dec '18

Hi everyone, So I have an idea which may or may not be a possibility. Currently Tor Onion Services do not need HTTPS since they are already end to end encrypted. That said multiple layers of crypto cannot hurt, Facebook for example uses this approach. So I have the idea of some sort of mechanism that lets you sign a self-signed tls certificate with your Onion Service's hs_ed25519_secret_key and Tor Browser trusting the tls certificate based on this signature. Would this approach work? Would it be worth the effort? Look forward to hearing your thoughts :) Cordially, Nathaniel Suchy

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Re: [tor-dev] Regarding projects and a begineer guide.
by teor 21 Dec '18

21 Dec '18

Hi, Here's the torsocks README: https://gitweb.torproject.org/torsocks.git/tree/README.md You could start by building and installing torsocks: https://gitweb.torproject.org/torsocks.git/tree/INSTALL T -- teor ---------------------------------------------------------------------- > On 16 Dec 2018, at 01:26, Durgesh Kumar <durgesh.17bcs1179(a)abes.ac.in> wrote: > > Thanks for your reply.. > > I am intrested in TORSOCKS under usability category. > Can you please provide me a begineer guide about the project so that i can get familiar with it. > > Sorry for late reply. > > > >> On Mon 10 Dec, 2018, 6:40 AM teor, <teor(a)riseup.net> wrote: >> Hi, >> >> > On 7 Dec 2018, at 02:28, Durgesh Kumar <durgesh.17bcs1179(a)abes.ac.in> wrote: >> > >> > Dear sir/mam >> > I am durgesh kumar from ABES engineering college,ghaziabad,uttar pradesh,india. >> > >> > I am currently in 2nd year of my graduation(Btech CSE ) >> > >> > I want to contribute in some of your prestigious project. So i request you to please provide me some of your top priority project and a begineer guide. >> > >> > I hope you will concern my request. >> >> Here's a list of our projects and some project ideas: >> https://www.torproject.org/getinvolved/volunteer.html.en#Projects >> >> Let us know which ones you're interested in. >> >> T >>

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Update on Guardian Project Pluggable Transport work
by Hans-Christoph Steiner 13 Dec '18

13 Dec '18

The Guardian Project "PLUTO" project is our name for the work we're doing around Pluggable Transports. If you want to follow this work more closely, you can ask n8fr8 to add you to our semi-private PLUTO mailing list. n8fr8 is currently working on integrating PTs into Android apps in a reusable way. That work is mostly in https://github.com/guardianproject/AndroidPluggableTransports I recently did some work to port snowflake to Android. That should be useable now, but with some open issues about repeatable builds and verification that non-free libs are not linked in. That's mostly here: https://github.com/keroserene/snowflake/pull/43 Then we're doing full stack prototypes for using PTs in Android apps, based on Wikipedia, F-Droid and an RFA app. That stuff is scattered around. >From that work, uniqx (Michael Poehn) has produced a PT bridge server setup automation: https://gitlab.com/uniqx/pt-socks5-over-obfs4proxy uniqx and I are now focused on Encrypted SNI for use as a PT, so there will be some server automation around that, e.g. custom openssl/mod_ssl build included. .hc -- PGP fingerprint: EE66 20C7 136B 0D2C 456C 0A4D E9E2 8DEA 00AA 5556 https://pgp.mit.edu/pks/lookup?op=vindex&search=0xE9E28DEA00AA5556

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prob_distr.c: LogLogistic fails stochastic tests on 32-bits mingw
by George Kadianakis 13 Dec '18

13 Dec '18

Hello Riastradh, as discussed on IRC, Appveyor recently started failing the stochastic tests of LogLogistic on 32-bit builds: https://github.com/torproject/tor/pull/576 https://ci.appveyor.com/project/torproject/tor/builds/20897462 I managed to reproduce the breakage by cross-compiling Tor and running the tests with wine, using this script of ahf: https://github.com/ahf/tor-win32/ Here are my findings: The following two test cases are breaking 100% reproducibly: ok = test_stochastic_log_logistic_impl(M_E, 1e-1); ok = test_stochastic_log_logistic_impl(exp(-10), 1e-2); The breakage seems to be because of the beta parameter. In particular, it seems like the test will break with any beta <= 0.26, and will succeed with a beta >= 0.27. The space in between is still unclear ;) I haven't managed to figure out what's actually offending the test but I can reproduce this so I can do some digging if you have any ideas. FWIW, I haven't noticed any other stochastic test breakage. Cheers!

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