tor-dev September 2011

tor-dev@lists.torproject.org

25 participants
24 discussions

Future direction for torperf
by Thomas S. Benjamin 30 Sep '11

30 Sep '11

Dear all, I am working on a re-design of torperf that will use a central python script to automate initiation and control of torperf experiments. I have a very rough draft that provides the most basic level of functionality in tomb/torperf.git branch 3280, and have ticket #3280 as wanting review. The code needs substantial improvement, but I would love feedback on my general approach before I spend a lot of time on grooming this specific version. If you use torperf please consider giving me feedback on the direction in which I am heading with this. I want to make sure that I am designing something that will work for other people, rather than just for my own experiments. I have chosen not to merge into a branch of torperf.git because my working style involves lots of frequent verbose commits, which would be distracting for most people. I will roll together the many commits before merging into torperf.git -- Sincerely Yours, ---Thomas S. Benjamin

2 1

سلام برنامه تور فارسی برای ایران می خواستم
by Mohammad Mo 29 Sep '11

29 Sep '11

سلام برنامه تور فارسی برای ایران می خواستم ولی تاحالا هیچ جوابی به فارسی دریافت نکرده ام

1 0

Proposed addition to Proposal 179
by Tim Wilde 28 Sep '11

28 Sep '11

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hey All, In some recent research we came across another easily-fingerprintable attribute of the Tor TLS handshake, so I would like to propose this addition to Proposal 179: https://github.com/twilde/torspec/commit/c202230b40c72cbdbe43bbda9cc1a7caad… Or, if in my git-newb-ish-ways I represent this correctly: git://github.com/twilde/torspec.git@c202230b40 Short summary: we should send an SSL Session ID, even if we don't track it or ever use it (which I wouldn't suggest we do) because not sending one makes us stick out like a sore thumb. :) Apologies if my git-newb-ish-nes makes this more difficult to grab, pointers welcome (I may be a git newb but I'm totally in love with it, mmm, sexy VCS :)). Thanks, Tim - -- Tim Wilde, Senior Software Engineer, Team Cymru, Inc. twilde(a)cymru.com | +1-847-378-3333 | http://www.team-cymru.org/ -----BEGIN PGP SIGNATURE----- iEYEARECAAYFAk6DkC0ACgkQluRbRini9tgfGACeKF41vKvoOvGFEHq5JXU9/u38 RWsAn1mb6MX0gvut6/ROYl0Kg6NQoF/e =2PWa -----END PGP SIGNATURE-----

1 0

Dynamic Throttling in Tor
by Rob Jansen 27 Sep '11

27 Sep '11

Hello, We've been exploring dynamic algorithms for throttling Tor clients. We've come up with three algorithms that are easier to maintain than static throttling (i.e. don't need to be reconfigured often), and produce significant performance benefits for web clients at the expense of bulk clients. Details are available in our technical report: http://www-users.cs.umn.edu/~jansen/papers/throttling-umntr11-019.pdf We are looking for feedback and are wondering if these algorithms look useful to Tor. They have already been implemented, and patches can be prepared if there is interest. Best regards, Rob -- Rob G. Jansen U.S. Naval Research Laboratory rob.g.jansen(a)nrl.navy.mil 202.767.2389

1 0

Re: [tor-dev] MITM for TOR
by andrew＠torproject.org 26 Sep '11

26 Sep '11

On Fri, Sep 23, 2011 at 03:52:25PM +0200, robvanderhoeven(a)ziggo.nl wrote 0.5K bytes in 20 lines about: : I build a small Monitor In The Middle (MITM) proxy that can be used to : study the communication between TOR and the browser. Hope this can be : used to improve TOR. : : It's small but quite powerful. Wrote an article about it on my blog: : : http://freedomboxblog.nl/mitm-for-tor/ It seems you responded to another thread with a new subject, perhaps this has confused others. How does this differ from the tamper data extension in Firefox? https://addons.mozilla.org/en-US/firefox/addon/tamper-data/ In either case, did you find anything in the interaction between firefox and the Tor socks proxy? From you blog post, it looks like Tor socks interaction is quick, and the performance of everything else is dependent on the active circuit. And, it's Tor, not TOR. See https://www.torproject.org/docs/faq.html.en#WhyCalledTor for the details. -- Andrew pgp key: 0x74ED336B

2 2

Proposal: Optimistic Data for Tor: Client Side
by Ian Goldberg 24 Sep '11

24 Sep '11

Sorry this took so long. As usual, things got inserted ahead of it in the priority queue. :-p Anyway, here's the client-side sibling proposal to the already-implemented 174. It cuts down time-to-first-byte for HTTP requests by 25 to 50 percent, so long as your SOCKS client (e.g. webfetch, polipo, etc.) is patched to support it. (With that kind of speedup, I think it's worth it.) Discuss. ;-) - Ian

4 9

The Torouter project - where are we now?
by Runa A. Sandvik 24 Sep '11

24 Sep '11

Hi everyone, I am trying to figure out how we can move the Torouter project forward. In this email, I will try to summarize the current status of this project. The Torouter project has a total of four bugs in Trac. These are #2334, #2376, #2370 and #2596. #2334: Torouter on Buffalo breaks with large cached-descriptors[.new] files. The quick and easy solution here is to attach a USB stick to the router and use it as Tor's data directory. However, it would be great if someone could take a look at this and figure out a way to solve it. #2376: Torouter on OpenWrt shouldn't have its data directory in /tmp/. The problem with having Tor's data directory in /tmp is that whenever Torouter is rebooted, Tor generates new keys and gets a new fingerprint. There are a couple of different ways to solve this problem; Karsten suggested that we could modify OpenWrt to stop creating a /tmp partition. This probably means that we will have to ship our own OpenWrt image. I'm thinking that another option would be to modify the Tor-OpenWrt-package to use / as the data directory instead of /tmp. However, I wonder if 64M (no matter how it's partitioned) of space on the Buffalo router is insufficient as long as #2334 remains open. #2370: Torouter basic Web UI for OpenWrt. I haven't tried the web interface myself, but development seems to be moving along nicely. I'm not sure what the remaining steps are, other than packaging it as tor-ui (or similar) for OpenWrt. #2596: Figure out a better name than "torouter". Andrew thinks we should come up with a better name for this project, one that does not have "Tor" in the name. Suggestions? The Torouter project also has some open questions (some are mentioned on https://trac.torproject.org/projects/tor/wiki/TheOnionRouter/Torouter as well): 1. How can we make sure that the version of Tor in OpenWrt is always up to date? Should we set up our own OpenWrt repository? Right now, the version of Tor in OpenWrt is 0.2.1.26. Also, should we offer packages for both stable and unstable? 2. We want to collect statistics, which means that we need to ship a GeoIP file as well. I'm thinking we should create a tor-geoipdb package for OpenWrt. Thoughts? 3. Do we want one Tor process for bridging and one for the transparent wifi network? I think this sounds good, if the router can handle it. If not, then just running a bridge is ok too. Have I missed anything important? Are there any other packages that we should include in OpenWrt? Other comments or suggestions? If you have more information or would like to help out, please let me know. Thanks, -- Runa A. Sandvik

8 16

Re: [tor-dev] Proposal 185: Directory caches without DirPort
by Karsten Loesing 23 Sep '11

23 Sep '11

Looks like we lost tor-dev somewhere. Quoting Nick's reply without cutting out stuff I have no comments to. On 9/22/11 10:16 PM, Nick Mathewson wrote: > On Thu, Sep 22, 2011 at 4:49 AM, Karsten Loesing > <karsten.loesing(a)gmx.net> wrote: >> Hi Nick, >> >> and here are a few comments to your proposal 185: >> >> On 9/20/11 9:34 PM, Nick Mathewson wrote: >>> Configuration: >>> >>> Add a new torrc option, "DirCache". Its values can be "0", "1", >>> and "auto". If it is 0, we never act as a directory cache, even >>> if DirPort is set. >> >> Do these relays set "dir-cache 0" in their router descriptors? Or do >> they just not include "dir-cache 1"? > > They just do not include "dir-cache 1". I'll make this more explicit. > >> But if they set a non-zero >> DirPort, how will the directory authorities and clients know that the >> node doesn't want to act as a directory cache? > > If you don't want to act as a directory cache, you don't publish DirPort. > > "dir-cache 0" wouldn't work to disable a dirport published in your > "router" line, since old Tors wouldn't recognize the dir-cache option, > and so wouldn't know that they weren't supposed to use DirPort. > >> >>> If it is 1, then we act as a directory cache >>> according to same rules as those used for nodes that set a >>> DirPort. If it is "auto", then Tor decides whether to act as a >>> directory cache. >> >> What are the rules when setting a DirPort? Successful self-test and >> minimum advertised bandwidth? > > I believe so, except of course you don't need to have a reachable > DirPort in this case. > >> How's "1" different from "auto" if Tor >> decides whether to act as a directory cache in both cases? > > "1" is "I want to be a directory cache"; "auto" is "use me as a > directory cache if that would help". I think that auto might be in > the future be more adaptive, depending on the state of the network and > the number of directory caches. > > I would like "DirCache auto" to be something we're comfortable making > the new default. > >>> Consensus: >>> >>> Authorities should assign a "DirCache" flag to all nodes running >>> as a directory cache that do not set a DirPort. >> >> Would it make sense to have them assign the "DirCache" flag for nodes >> with a non-zero DirPort, too? > > IMO that would just use up space. Is there an argument in favor? Yup, I agree with you that it uses up space. My thinking was that clients wouldn't have to check two things (non-zero Dir port or DirCache flag) to learn whether a relay has directory info for them, but just one thing. And it could lead to some confusion when people try to understand dir-spec.txt or the TorStatus output (once it displays this flag). Not very strong arguments though. I also wasn't certain if the proposal was wrong here and you really meant that the flag would be assigned to all directory caches. If the proposal says what you meant, carry on. :) Best, Karsten

2 1

Proposal 184: Miscellaneous changes for a v3 Tor link protocol
by Nick Mathewson 23 Sep '11

23 Sep '11

Filename: 184-v3-link-protocol.txt Title: Miscellaneous changes for a v3 Tor link protocol Author: Nick Mathewson Created: 19-Sep-2011 Status: Open Target: 0.2.3.x Overview: When proposals 176 and 179 are implemented, Tor will have a new link protocol. I propose two simple improvements for the v3 link protocol: a more partitioned set of which types indicate variable-length cells, and a better way to handle link padding if and when we come up with a decent scheme for it. Motivation: We're getting a new link protocol in 0.2.3.x, thanks (again) to TLS fingerprinting concerns. When we do, it'd be nice to take care of some small issues that require a link protocol version increment. First, our system for introducing new variable-length cell types has required a protocol increment for each one. Unlike fixed-length (512 byte) cells, we can't add new variable-length cells in the existing link protocols and just let older clients ignore them, because unless the recipient knows which cells are variable-length, it will treat them as 512-byte cells and discard too much of the stream or too little. In the past, it's been useful to be able to introduce new cell types without having to increment the link protocol version. Second, once we have our new TLS handshake in place, we will want a good way to address the remaining fingerprinting opportunities. Some of those will likely involve traffic volume. We can't fix that easily with our existing PADDING cell type, since PADDING cells are fixed-length, and wouldn't be so easy to use to break up our TLS record sizes. Design: Indicating variable-length cells. Beginning with the v3 link protocol, we specify that all cell types in the range 128..255 indicate variable-length cells. Cell types in the range 0..127 are still used for 512-byte cells, except that the VERSIONS cell type (7) also indicates a variable-length cell (for backward compatibility). As before, all Tor instances must ignore cells with types that they don't recognize. Design: Variable-length padding. We add a new variable-length cell type, "VPADDING", to be used for padding. All Tor instances may send a DROP cell at any point that a VERSIONS cell is not required; a VPADDING cell's body may be any length; the body of a VPADDING cell MAY have any content. Upon receiving a VPADDING cell, the recipient should drop it, as with a PADDING cell. Interaction with proposal 176: Proposal 176 says that during the v3 handshake, no cells other than VERSIONS, AUTHENTICATE, AUTH_CHALLENGE, CERT, and NETINFO are allowed, and those are only allowed in their standard order. If this proposal is accepted, then VPADDING cells should also be allowed in the handshake at any point after the VERSIONS cell. They should be included when computing the "SLOG" and "CLOG" handshake-digest fields of the AUTHENTICATE cell. Notes on future-proofing: It may be in the future we need a new cell format that is neither the original 512-byte format nor the variable-length format. If we do, we can just increment the link protocol version number again. Right now we have 10 cell types; with this proposal and proposal 176, we will have 14. It's unlikely that we'll run out any time soon, but if we start to approach the number 64 with fixed-length cell types or 196 with var-length cell types, we should consider tweaking the link protocol to have a variable-length cell type encoding.

3 2

Proposal 185: Directory caches without DirPort
by Nick Mathewson 22 Sep '11

22 Sep '11

Filename: 185-dir-without-dirport.txt Title: Directory caches without DirPort Author: Nick Mathewson Created: 20-Sep-2011 Status: Open Overview: Exposing a directory port is no longer necessary for running as a directory cache. This proposal suggests that we eliminate that requirement, and describes how. Motivation: Now that we tunnel directory connections by default, it is no longer necessary to have a DirPort to be a directory cache. In fact, bridges act as directory caches but do not actually have a DirPort exposed. It would be nice and tidy to expand that property to the rest of the network. Configuration: Add a new torrc option, "DirCache". Its values can be "0", "1", and "auto". If it is 0, we never act as a directory cache, even if DirPort is set. If it is 1, then we act as a directory cache according to same rules as those used for nodes that set a DirPort. If it is "auto", then Tor decides whether to act as a directory cache. Advertising cache status: Nodes which are running as a directory cache but which do not have a DirPort set should set the entry "dir-cache 1" in their router descriptors. Consensus: Authorities should assign a "DirCache" flag to all nodes running as a directory cache that do not set a DirPort. This does not require a new version of the consensus algorithm.

3 2

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

tor-dev September 2011