[tor-bugs] #10418 [Tor Launcher]: Make a "Use Default Bridges" Radio button in the Tor Launcher Bridge UI

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#10418: Make a "Use Default Bridges" Radio button in the Tor Launcher Bridge UI
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     Reporter:  mikeperry     |      Owner:  brade
         Type:  enhancement   |     Status:  reopened
     Priority:  major         |  Milestone:
    Component:  Tor Launcher  |    Version:
   Resolution:                |   Keywords:  MikePerry201402R
Actual Points:                |  Parent ID:
       Points:                |
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Comment (by mcs):

 Replying to [comment:37 mikeperry]:
 > This appears to have a bug with how it handles the torrc. The
 ClientTransportPlugin lines are not being preserved. The result is that if
 you configure pluggable transports like obfs3, upon the second invocation
 the browser will fail to connect to the network. You can observe this with
 gk's test build for OSX, which contain working obfs3 bridge lines.

 I cannot find a way to cause the ClientTransportPlugin lines to be lost.
 How can I reproduce the problem you saw?

 The ClientTransportPlugin settings are in torrc-defaults, and Tor Launcher
 never does anything to modify ClientTransportPlugin configuration.

 The second time I start TBB, I do see several messages like the following
 in the tor log:

 {{{
 Mar 04 09:57:54.000 [warn] We were supposed to connect to bridge
 '109.105.109.163:47779'
 using pluggable transport 'obfs3', but we can't find a pluggable transport
 proxy
 supporting 'obfs3'. This can happen if you haven't provided a
 ClientTransportPlugin
 line, or if your pluggable transport proxy stopped running.
 }}}

 But the obfs3 process is running:
 {{{
 brade 3270 ... S 10:03AM 0:01.12 python PluggableTransports/obfsproxy.bin
 managed
 }}}

 And bootstrapping finishes.  In fact, netstat shows outbound TCP
 connections to some of the configured obfs3 bridges.

 I wonder if there is a race inside tor between starting the client
 transport plugins and trying to use the bridges?  As we discussed, when
 default bridges are configured, Tor Launcher always starts tor with
 DisableNetwork=1.  Then it does a SETCONF to set UseBridges=1 and to
 configure the bridges (Bridge=<list>).  Then it does a second SETCONF with
 DisableNetwork=0.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/10418#comment:39>
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