[tor-bugs] #6996 [Obfsproxy]: Problems with starting managed Obfsproxy server when installed via debian package and with Tor as service

Sat Sep 29 14:58:34 UTC 2012

#6996: Problems with starting managed Obfsproxy server when installed via debian
package and with Tor as service
-----------------------+----------------------------------------------------
 Reporter:  linda      |          Owner:  asn             
     Type:  defect     |         Status:  new             
 Priority:  normal     |      Milestone:                  
Component:  Obfsproxy  |        Version:  Tor: 0.2.3.22-rc
 Keywords:             |         Parent:                  
   Points:             |   Actualpoints:                  
-----------------------+----------------------------------------------------
 On a Ubuntu 12.04 "precise" host, I have installed obfsproxy and upgraded
 tor via the debian packages.  More specifically:

 {{{
 $> sudo apt-get install -y tor obfsproxy
 ...
 $> which obfsproxy
 /usr/bin/obfsproxy
 $> obfsproxy --version
 obfsproxy 0.1.4 (git-94ebc4c3edf1e3e5)
 $> tor --version
  [notice] Tor v0.2.3.22-rc (git-4a0c70a817797420) running on Linux.
  [notice] Tor can't help you if you use it wrong! Learn how to be safe at
 https://www.torproject.org/download/download#warning
 Tor version 0.2.3.22-rc (git-4a0c70a817797420).
 }}}

 I'm typically managing Tor via:

 {{{
 $> sudo service tor start|stop|status
 }}}

 My {{{torrc}}} is:

 {{{
 $> grep -v "^#" /etc/tor/torrc | sed '/^$/d'
 SocksPort 0
 RunAsDaemon 1
 User debian-tor
 ORPort 8888
 Nickname sricslbridge2
 ExitPolicy reject *:* # no exits allowed
 BridgeRelay 1
 ServerTransportPlugin obfs2 exec /usr/bin/obfsproxy --managed
 }}}

 After starting Tor, the following process is running.  But the obfsproxy
 process is missing, because of the following log output:

 {{{
 $> ps axu | grep tor
 107       2228  0.7  1.3 379396 53244 ?        Sl   07:27   0:01
 /usr/sbin/tor --defaults-torrc /usr/share/tor/tor-service-defaults-torrc
 --hush
 ...
 $> ps axu | grep obfs
 $> sudo grep obfs /var/log/tor/log
  [warn] Could not launch managed proxy executable at '/usr/bin/obfsproxy'
 ('Permission denied').
 }}}

 When I turn {{{Log}}} on via {{{torrc}}}, the log output is slightly more
 verbose:

 {{{
 $> sudo grep -v "^#" /etc/tor/torrc | grep Log
 Log debug file /var/log/tor/debug.log
 $> sudo grep obfs /var/log/tor/debug.log
  [info] launch_managed_proxy(): Managed proxy at '/usr/bin/obfsproxy' has
 spawned with PID '2423'.
  [info] handle_proxy_line(): Got a line from managed proxy
 '/usr/bin/obfsproxy': (ERR: Failed to spawn background process - code 9/D)
  [warn] Could not launch managed proxy executable at '/usr/bin/obfsproxy'
 ('Permission denied').
 }}}

 The reason I was thinking it has to do with my init script (although I
 don't think I changed it myself.  It was probably installed with Tor
 0.2.2.x originally), is that I tried to run multiple Tor processes
 controlled via init.d using the instructions here:
   [https://www.torservers.net/wiki/setup/server#multiple_tor_processes]
 And the effect was that obfsproxy did start using this alternative init
 script.  However, I reverted back to the original init script because the
 stopping of multiple Tor processes didn't work and I realized that I only
 need one Tor process to support a regular and an obfuscated bridge.

 In the hope that the permission required to start the managed obfsproxy
 had to do with write permissions in certain locations, I attempted: (but
 it didn't resolve the problem)
 {{{
 $> sudo chown -R debian-tor:adm /var/tor
 $> sudo ls -la /var/tor
 total 6816
 drwx------  3 debian-tor adm     4096 Sep 28 15:27 .
 drwxr-xr-x 13 root       root    4096 Sep 29 07:23 ..
 -rw-------  1 debian-tor adm    16947 Sep 28 13:11 cached-certs
 -rw-------  1 debian-tor adm   706188 Sep 28 13:11 cached-consensus
 -rw-------  1 debian-tor adm  4237891 Sep 28 14:36 cached-descriptors
 -rw-------  1 debian-tor adm   184873 Sep 28 14:38 cached-descriptors.new
 -rw-------  1 debian-tor adm   594762 Sep 28 13:11 cached-microdesc-
 consensus
 -rw-------  1 debian-tor adm  1172036 Sep 28 14:36 cached-microdescs
 -rw-------  1 debian-tor adm    23655 Sep 28 14:36 cached-microdescs.new
 -rw-------  1 debian-tor adm       60 Sep 28 14:36 fingerprint
 drwx------  2 debian-tor adm     4096 Sep 28 13:11 keys
 -rw-------  1 debian-tor adm        0 Sep 28 14:36 lock
 -rw-------  1 debian-tor adm     1510 Sep 28 15:27 state
 $> sudo ls -la /var/run/tor
 total 8
 drwxr-s---  2 debian-tor debian-tor 100 Sep 29 07:50 .
 drwxr-xr-x 21 root       root       700 Sep 29 07:49 ..
 srw-rw----  1 debian-tor debian-tor   0 Sep 29 07:50 control
 -rw-r-----  1 debian-tor debian-tor  32 Sep 29 07:50 control.authcookie
 -rw-r--r--  1 debian-tor debian-tor   5 Sep 29 07:50 tor.pid
 }}}

 I'm attaching the short {{{log}}} and the more detailed {{{debug.log}}}.
 Also the init scripts {{{tor}}} (which must have come with the first Tor
 installation) and {{{tor.MULTIPLE}}}, which came from the commands below,
 are attached.

 {{{
 $> cd /etc/init.d
 $> sudo mv tor tor.ORIG
 $> sudo wget -O tor https://www.torservers.net/misc/config/initd-tor
 $> sudo mv tor tor.MULTIPLE
 $> sudo mv tor.ORIG tor
 }}}

 Thanks!
 Linda

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6996>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online