Opened 2 months ago

Last modified 6 days ago

#29875 assigned defect

Going from obfs4 to snowflake using the Tor Network Settings from the Torbutton doesn't work

Reported by: cypherpunks Owned by:
Priority: Medium Milestone: Tor: 0.4.1.x-final
Component: Core Tor/Tor Version: Tor: 0.3.2.7-rc
Severity: Normal Keywords: tbb-needs, 034-backport, 034-backport, 035-backport, 040-backport, 041-should, network-team-roadmap-2019-Q1Q2
Cc: dcf, arlolra, cohosh, teor Actual Points:
Parent ID: Points:
Reviewer: Sponsor: Sponsor19-must

Description

Going from obfs4 to snowflake using the Tor Network Settings from the Torbutton doesn't work, i.e. nothing happens and no website can load, if I restart the browser then snowflake works perfectly

Child Tickets

TicketStatusOwnerSummaryComponent
#24367assignedChanging pluggable transports (during start-up) in Tor Browser is brokenCore Tor/Tor

Change History (11)

comment:1 Changed 2 months ago by gk

Yeah, here is what I get in my logs

Mar 25 12:59:36.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Mar 25 12:59:36.000 [notice] Our circuit 0 (id: 40) died due to an invalid selected path, purpose General-purpose client. This may be a torrc configuration issue, or a bug.
[03-25 12:59:36] TorLauncher DBUG: Event response: 650 WARN Failed to find node for hop #1 of our path. Discarding this circuit. 
[03-25 12:59:36] TorLauncher DBUG: Event response: 650 NOTICE Our circuit 0 (id: 40) died due to an invalid selected path, purpose General-purpose client. This may be a torrc configuration issue, or a bug. 
Mar 25 12:59:37.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
[03-25 12:59:37] TorLauncher DBUG: Event response: 650 WARN Failed to find node for hop #1 of our path. Discarding this circuit. 
Mar 25 12:59:38.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
[03-25 12:59:38] TorLauncher DBUG: Event response: 650 WARN Failed to find node for hop #1 of our path. Discarding this circuit. 
Mar 25 12:59:39.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.

and so on.

comment:2 Changed 2 months ago by cypherpunks

Many thanks Georg for the confirmation.

comment:3 Changed 2 months ago by dcf

This is reminiscent of #12774 for meek; but in that case it's caused by a race between multiple copies of Firefox. There's no Firefox here, but maybe it's related to a deeper cause, which is that tor quickly starts multiple copies of the transport program when you change transports, then kills all but one of them. It could be interfering with rendezvous or something.

comment:4 Changed 2 months ago by ahf

Component: Obfuscation/SnowflakeCore Tor/Tor
Milestone: Tor: 0.4.0.x-final
Version: Tor: 0.4.0.1-alpha

This looks like a core tor PT regression.

comment:5 Changed 2 months ago by arma

GeKo, can you confirm this behavior on Tor 0.3.5 as well?

That is, we need to figure out if this is a regression in Tor 0.4.0, or a bug that's been here for longer.

comment:6 in reply to:  5 Changed 2 months ago by gk

Cc: teor added
Keywords: tbb-wants added
Version: Tor: 0.4.0.1-alphaTor: 0.3.2.7-rc

Replying to arma:

GeKo, can you confirm this behavior on Tor 0.3.5 as well?

Yes.

That is, we need to figure out if this is a regression in Tor 0.4.0, or a bug that's been here for longer.

In fact, the last good release is 0.3.2.6-alpha. More precisely 690f646bf8a5de9b is the first bad revision, which tries to work around my #24367. I guess all that trouble speaks for fixing the latter once and for all (too). :)

comment:7 Changed 2 months ago by teor

Keywords: tbb-needs 040-must 034-backport 035-backport 040-backport added; tbb-wants removed
Owner: set to teor
Sponsor: Sponsor19
Status: newassigned

I will try and fix #24367 and #29875. I also opened #29956 so we make tests for these kinds of bugs.

comment:8 Changed 8 weeks ago by teor

Keywords: 040-must removed
Milestone: Tor: 0.4.0.x-finalTor: 0.4.1.x-final
Owner: teor deleted
Sponsor: Sponsor19Sponsor19-must

comment:9 Changed 10 days ago by nickm

Keywords: 041-should added

comment:10 Changed 6 days ago by gaba

Keywords: network-team-roadmap-2019-Q1Q2 added

comment:11 Changed 6 days ago by gk

Okay, here come the steps tor reproduce this bug on a Linux system:

1) Take a clean, new Tor Browser alpha.
2) Start it with ./start-tor-browser.desktop --debug on the command line, but don't connect directly. Rather, configure obfs4 to use one of the built-in bridges.
3) Continue bootstrap afterwards.
4) When the browser window shows up click on the onion button on the toolbar and select "Tor Network Settings...".
5) Change the the PT selected to use snowflake, click OK.
6) You should see the Failed to find node for hop #1 of our path messages right away.

Note: See TracTickets for help on using tickets.