Opened 9 months ago

Closed 6 weeks ago

#28293 closed defect (worksforme)

Corrupted obfs4proxy executable after restarts when bridges were offline

Reported by: traumschule Owned by:
Priority: Medium Milestone:
Component: Circumvention/Pluggable transport Version:
Severity: Normal Keywords:
Cc: Actual Points:
Parent ID: Points:
Reviewer: Sponsor:

Description

Testing bridges in TB 8.0.3 (with tor 0.3.4.8) two of the requested bridges were offline (see #28291) and bootstrapping was stuck at 71% (This is a known issue tor prior 0.3.5, see #25502).

Going back and changing from requested to built in obfs4 bridges didn't have any effect, bootstrapping still hung.

After restarting the browser it hung at 20%. Restarted the browser again and requested new bridges the UI told

Connecting to a relay directory failed (missing pluggable transport...

(took debug and info logs, will attach them later)

After a hint by dcf1 on IRC i turned on logging:

To enable obfs4proxy logging, edit Browser/TorBrowser/Data/Tor/torrc-defaults and add "--enableLogging --logLevel=INFO --unsafeLogging" to the "ClientTransportPlugin obfs2,obfs3,obfs4,scramblesuit" line.
Then the log will be written to Browser/TorBrowser/Data/Tor/pt_state/obfs4proxy.log

11/3/18, 05:44:15.821 [NOTICE] DisableNetwork is set. Tor will not make or accept non-control network connections. Shutting down all existing connections. 
11/3/18, 05:44:15.821 [NOTICE] DisableNetwork is set. Tor will not make or accept non-control network connections. Shutting down all existing connections. 
11/3/18, 05:44:15.821 [NOTICE] DisableNetwork is set. Tor will not make or accept non-control network connections. Shutting down all existing connections. 
11/3/18, 05:44:15.822 [NOTICE] Opening Socks listener on 127.0.0.1:9150 
11/3/18, 05:44:16.722 [WARN] The communication stream of managed proxy './TorBrowser/Tor/PluggableTransports/obfs4proxy' is 'closed'. Most probably the managed proxy stopped running. This might be a bug of the managed proxy, a bug of Tor, or a misconfiguration. Please enable logging on your managed proxy and check the logs for errors. 
11/3/18, 05:44:16.722 [NOTICE] Ignoring directory request, since no bridge nodes are available yet. 
11/3/18, 05:44:17.788 [NOTICE] Bridge 'Unnamed' has both an IPv4 and an IPv6 address.  Will prefer using its IPv4 address (146.196.65.18:443) based on the configured Bridge address. 
11/3/18, 05:44:17.788 [NOTICE] Bootstrapped 5%: Connecting to directory server 
11/3/18, 05:44:17.790 [WARN] We were supposed to connect to bridge '102.253.68.166:43775' using pluggable transport 'obfs4', but we can't find a pluggable transport proxy supporting 'obfs4'. This can happen if you haven't provided a ClientTransportPlugin line, or if your pluggable transport proxy stopped running. 
11/3/18, 05:44:17.791 [WARN] Problem bootstrapping. Stuck at 5%: Connecting to directory server. (Can't connect to bridge; PT_MISSING; count 1; recommendation warn; host 8D5F75269D5E0D2B9A1B0FA3D5A3BCA0EFC7F313 at 102.253.68.166:43775) 
11/3/18, 05:44:17.809 [WARN] We were supposed to connect to bridge '146.196.65.18:443' using pluggable transport 'obfs4', but we can't find a pluggable transport proxy supporting 'obfs4'. This can happen if you haven't provided a ClientTransportPlugin line, or if your pluggable transport proxy stopped running. 
11/3/18, 05:44:17.809 [WARN] Problem bootstrapping. Stuck at 5%: Connecting to directory server. (Can't connect to bridge; PT_MISSING; count 2; recommendation warn; host 642201EDF4BF5E3898E4F34B930032B00E3BA27C at 146.196.65.18:443) 
11/3/18, 05:44:17.810 [WARN] We were supposed to connect to bridge '24.154.179.248:44673' using pluggable transport 'obfs4', but we can't find a pluggable transport proxy supporting 'obfs4'. This can happen if you haven't provided a ClientTransportPlugin line, or if your pluggable transport proxy stopped running. 
11/3/18, 05:44:17.810 [WARN] Problem bootstrapping. Stuck at 5%: Connecting to directory server. (Can't connect to bridge; PT_MISSING; count 3; recommendation warn; host 1AAEE6A3B52C69A3D74E9EDEEDE9F15BE3182C3F at 24.154.179.248:44673) 
11/3/18, 05:44:17.812 [NOTICE] Closing no-longer-configured Socks listener on 127.0.0.1:9150 
11/3/18, 05:44:17.812 [NOTICE] DisableNetwork is set. Tor will not make or accept non-control network connections. Shutting down all existing connections. 
11/3/18, 05:44:17.812 [NOTICE] Closing old Socks listener on 127.0.0.1:9150 

Run manually:

./Browser/TorBrowser/Tor/PluggableTransports/obfs4proxy --enableLogging --logLevel=INFO --unsafeLogging
Segmentation fault

With gdb:

$ gdb --args ./Browser/TorBrowser/Tor/PluggableTransports/obfs4proxy --enableLogging --logLevel=INFO --unsafeLogging                                          
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"/home/tbb/tor-browser_en-US/./Browser/TorBrowser/Tor/PluggableTransports/obfs4proxy": not in executable format: File truncated                                                   
(gdb) run                                                                                                                                                                                             
Starting program:  --enableLogging --logLevel=INFO --unsafeLogging
No executable file specified.

I have no clue how it got corrupted, will attach it and a screenshot of the UI that maybe should also tell something like:

Failed to start bridge executable. Please try again with a fresh Tor Browser.

Child Tickets

Attachments (2)

tor-launcher-failed-obfs4proxy.png (29.5 KB) - added by traumschule 9 months ago.
> Tor failed to establish a Tor network connection. Connecting to a relay directory failed (missing pluggable transport
obfs4proxy (954.5 KB) - added by traumschule 9 months ago.
./Browser/TorBrowser/Tor/PluggableTransports/obfs4proxy

Download all attachments as: .zip

Change History (6)

Changed 9 months ago by traumschule

Tor failed to establish a Tor network connection. Connecting to a relay directory failed (missing pluggable transport

Changed 9 months ago by traumschule

Attachment: obfs4proxy added

./Browser/TorBrowser/Tor/PluggableTransports/obfs4proxy

comment:1 Changed 6 months ago by ahf

Parent ID: #25502

comment:2 Changed 6 months ago by teor

Owner: asn deleted
Status: newassigned

asn does not need to own any obfuscation tickets any more. Default owners are trouble.

comment:3 Changed 5 months ago by cohosh

Status: assignednew

tickets were assigned to asn, setting them as unassigned (new) again.

comment:4 Changed 6 weeks ago by teor

Resolution: worksforme
Status: newclosed

This might be a bug on your system, or in the Tor Browser update process. It's unlikely to be a bug in tor.

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