You must connect to a socket file instead of a port for Tor Browser 6.5a6. Make automatic settings fallback to socket file if the port doesn't work (only for Linux so far, have not tested in OS X, and is not supported in Windows)

onionshare/onion.py

@@ -21,7 +21,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 from stem.control import Controller
 from stem import SocketError
 from stem.connection import MissingPassword, UnreadableCookieFile
-import os, sys, tempfile, shutil, urllib
+import os, sys, tempfile, shutil, urllib, platform
 
 from . import socks
 from . import helpers, strings
@@ -109,16 +109,20 @@ class Onion(object):
         if self.settings.get('connection_type') == 'automatic':
             # Automatically try to guess the right way to connect to Tor Browser
 
-            # Try connecting
-            try:
+            # Try connecting to control port
+            found_tor = False
+
             # If the TOR_CONTROL_PORT environment variable is set, use that
             env_port = os.environ.get('TOR_CONTROL_PORT')
             if env_port:
+                try:
                     self.c = Controller.from_port(port=int(env_port))
+                    found_tor = True
+                except:
+                    pass
 
             else:
                 # Otherwise, try default ports for Tor Browser, Tor Messenger, and system tor
-                    found_tor = False
                 try:
                     ports = [9151, 9153, 9051]
                     for port in ports:
@@ -126,10 +130,24 @@ class Onion(object):
                         found_tor = True
                 except:
                     pass
+
+            # If connecting to default control ports failed, so let's try
+            # guessing the socket file name next
             if not found_tor:
+                try:
+                    p = platform.system()
+                    if p == 'Linux':
+                        socket_file_path = '/run/user/{}/Tor/control.socket'.format(os.geteuid())
+                    elif p == 'Darwin':
+                        # TODO: figure out the unix socket path in OS X
+                        socket_file_path = '/run/user/{}/Tor/control.socket'.format(os.geteuid())
+                    elif p == 'Windows':
+                        # Windows doesn't support unix sockets
                         raise TorErrorAutomatic(strings._('settings_error_automatic'))
 
-            except TorErrorAutomatic:
+                    self.c = Controller.from_socket_file(path=socket_file_path)
+
+                except:
                     raise TorErrorAutomatic(strings._('settings_error_automatic'))
 
             # Try authenticating