[tor-bugs] #25600 [Obfuscation/Snowflake]: Tor eventually hits "No running bridges" with Snowflake

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#25600: Tor eventually hits "No running bridges" with Snowflake
-----------------------------------+------------------------
 Reporter:  cypherpunks            |          Owner:  (none)
     Type:  defect                 |         Status:  closed
 Priority:  Medium                 |      Milestone:
Component:  Obfuscation/Snowflake  |        Version:
 Severity:  Normal                 |     Resolution:  fixed
 Keywords:                         |  Actual Points:
Parent ID:                         |         Points:
 Reviewer:                         |        Sponsor:
-----------------------------------+------------------------
Changes (by dcf):

 * status:  merge_ready => closed
 * resolution:   => fixed


Comment:

 I tested the patch myself, copying the patched snowflake-client into a Tor
 Browser 8.0a8.

 The first time I tried, I got "No running bridges" after 11 minutes :/
 {{{
 06/11/18 06:07:56.600 [NOTICE] DisableNetwork is set. Tor will not make or
 accept non-control network connections. Shutting down all existing
 connections.
 06/11/18 06:07:56.600 [NOTICE] Opening Socks listener on 127.0.0.1:9150
 06/11/18 06:07:57.500 [NOTICE] Bootstrapped 80%: Connecting to the Tor
 network
 06/11/18 06:07:57.500 [NOTICE] Bootstrapped 85%: Finishing handshake with
 first hop
 06/11/18 06:07:59.700 [NOTICE] Bootstrapped 90%: Establishing a Tor
 circuit
 06/11/18 06:08:00.600 [NOTICE] new bridge descriptor 'flakey' (fresh):
 $2B280B23E1107BB62ABFC40DDCC8824814F80A72~flakey at 0.0.3.0
 06/11/18 06:08:01.200 [WARN] Your Guard
 $2B280B23E1107BB62ABFC40DDCC8824814F80A72
 ($2B280B23E1107BB62ABFC40DDCC8824814F80A72) is failing an extremely large
 amount of circuits. This could indicate a route manipulation attack,
 extreme network overload, or a bug. Success counts are 56/251. Use counts
 are 44/44. 247 circuits completed, 0 were unusable, 191 collapsed, and 2
 timed out. For reference, your timeout cutoff is 60 seconds.
 06/11/18 06:08:01.800 [NOTICE] Tor has successfully opened a circuit.
 Looks like client functionality is working.
 06/11/18 06:08:01.800 [NOTICE] Bootstrapped 100%: Done
 06/11/18 06:08:03.900 [NOTICE] New control connection opened from
 127.0.0.1.
 06/11/18 06:08:04.100 [NOTICE] New control connection opened from
 127.0.0.1.
 06/11/18 06:18:37.900 [WARN] Your Guard
 $2B280B23E1107BB62ABFC40DDCC8824814F80A72
 ($2B280B23E1107BB62ABFC40DDCC8824814F80A72) is failing a very large amount
 of circuits. Most likely this means the Tor network is overloaded, but it
 could also mean an attack against you or potentially the guard itself.
 Success counts are 87/288. Use counts are 48/48. 284 circuits completed, 0
 were unusable, 197 collapsed, and 2 timed out. For reference, your timeout
 cutoff is 60 seconds.
 06/11/18 06:18:59.400 [NOTICE] Delaying directory fetches: No running
 bridges
 06/11/18 06:18:59.400 [NOTICE] Application request when we haven't
 received a consensus with exits. Optimistically trying known bridges
 again.
 06/11/18 06:24:02.100 [NOTICE] Delaying directory fetches: No running
 bridges
 06/11/18 06:24:22.200 [NOTICE] Application request when we haven't
 received a consensus with exits. Optimistically trying known bridges
 again.
 }}}

 But I tried again, left it running overnight, restarted the next day, and
 didn't have another problem. So I'm going to go ahead with the theory that
 the first failure was a fluke or is some other bug.

 Anyway, I merged the patch in [https://gitweb.torproject.org/pluggable-
 transports/snowflake.git/commit/?id=6077141f4affdab9b7ce97a9b1c6859825eaaa29
 6077141f4affdab9b7ce97a9b1c6859825eaaa29].

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25600#comment:17>
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