after upgrade ubuntu from 15.04 to 16.04, tor obfs4 ClientTransportPlugin isn't work

Question

today i upgrade ubuntu from 15.04 to 16.04, after that my tor is down and i have the problem on /var/log/tor/log :

Apr 25 07:52:58.678 [warn] OpenSSL version from headers does not match the version we're running with. If you get weird crashes, that might be why. (Compiled with 1000207f: OpenSSL 1.0.2g 1 Mar 2016; running with 1000207f: OpenSSL 1.0.2g-fips 1 Mar 2016).

Apr 25 07:52:58.702 [notice] Tor v0.2.7.6 (git-605ae665009853bd) running on Linux with Libevent 2.0.21-stable, OpenSSL 1.0.2g-fips and Zlib 1.2.8. Apr 25 07:52:58.702 [notice] Tor can't help you if you use it wrong! Learn how to be safe at https://www.torproject.org/download/download#warning Apr 25 07:52:58.702 [notice] Read configuration file "/usr/share/tor/tor-service-defaults-torrc".

Apr 25 07:52:58.702 [notice] Read configuration file "/etc/tor/torrc". Apr 25 07:52:58.705 [notice] Opening Socks listener on 127.0.0.1:9050 Apr 25 07:52:58.706 [notice] Opening Control listener on /var/run/tor/control

Apr 25 07:52:58.000 [notice] Parsing GEOIP IPv4 file /usr/share/tor/geoip. Apr 25 07:52:58.000 [notice] Parsing GEOIP IPv6 file /usr/share/tor/geoip6.

Apr 25 07:52:58.000 [notice] Bootstrapped 0%: Starting Apr 25 07:52:58.000 [notice] Delaying directory fetches: No running bridges

Apr 25 07:52:58.000 [notice] Signaled readiness to systemd Apr 25 07:52:59.000 [warn] Could not launch managed proxy executable at '/usr/bin/obfs4proxy' ('Operation not permitted'). Apr 25 07:53:00.000 [notice] Bootstrapped 5%: Connecting to directory server

Apr 25 07:53:00.000 [warn] We were supposed to connect to bridge '192.210.206.101:38617' 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.

Apr 25 07:53:00.000 [warn] Problem bootstrapping. Stuck at 5%: Connecting to directory server. (Can't connect to bridge; PT_MISSING; count 1; recommendation warn; host 9E255A5456143C435D0EADAB1473A3884A29C8C4 at 192.210.206.101:38617)

Answer 1

This a problem in the tor package which makes it against apparmor rules to let tor run the obfs4proxy as root. The quickest workaround is to run tor as a normal user and not root. to do so, first stop the tor service:

$ sudo systemctl stop tor.service

and run tor as your own user:

$ tor

The other way is to change apparmor rules, but this need a deep understanding of apparmor. You can see here for getting the idea, but I'm not sure this will fix this since I'm not an expert in apparmor.

Here is the reported and confirmed bug.