Initial work on supporting the option to automatically attempt to fetch bridges based on the user's location if Tor fails to connect (censorship circumvention)

cli/onionshare_cli/settings.py

@@ -113,6 +113,7 @@ class Settings(object):
             "persistent_tabs": [],
             "locale": None,  # this gets defined in fill_in_defaults()
             "theme": 0,
+            "censorship_circumvention": False,
         }
         self._settings = {}
         self.fill_in_defaults()

cli/tests/test_cli_settings.py

@@ -36,6 +36,7 @@ class TestSettings:
             "bridges_custom": "",
             "persistent_tabs": [],
             "theme": 0,
+            "censorship_circumvention": False,
         }
         for key in settings_obj._settings:
             # Skip locale, it will not always default to the same thing

desktop/src/onionshare/resources/locale/en.json

@@ -63,6 +63,7 @@
     "gui_settings_tor_bridges": "Connect using a Tor bridge?",
     "gui_settings_tor_bridges_label": "Bridges help you access the Tor Network in places where Tor is blocked. Depending on where you are, one bridge may work better than another.",
     "gui_settings_bridge_use_checkbox": "Use a bridge",
+    "gui_settings_censorship_circumvention_checkbox": "Attempt to automatically find a bridge based on your country if Tor fails to connect",
     "gui_settings_bridge_radio_builtin": "Select a built-in bridge",
     "gui_settings_bridge_none_radio_option": "Don't use a bridge",
     "gui_settings_meek_lite_expensive_warning": "Warning: The meek-azure bridges are very costly for the Tor Project to run.<br><br>Only use them if unable to connect to Tor directly, via obfs4 transports, or other normal bridges.",

desktop/src/onionshare/tor_connection.py

@@ -41,7 +41,7 @@ from onionshare_cli.onion import (
 from . import strings
 from .gui_common import GuiCommon
 from .widgets import Alert
-
+from onionshare_cli.censorship import CensorshipCircumvention
 
 class TorConnectionDialog(QtWidgets.QProgressDialog):
     """
@@ -165,7 +165,7 @@ class TorConnectionWidget(QtWidgets.QWidget):
     success = QtCore.Signal()
     fail = QtCore.Signal(str)
 
-    def __init__(self, common, status_bar):
+    def __init__(self, common, status_bar, meek):
         super(TorConnectionWidget, self).__init__(None)
         self.common = common
         self.common.log("TorConnectionWidget", "__init__")
@@ -181,6 +181,8 @@ class TorConnectionWidget(QtWidgets.QWidget):
         )
         self.cancel_button.clicked.connect(self.cancel_clicked)
 
+        self.meek = meek
+
         progress_layout = QtWidgets.QHBoxLayout()
         progress_layout.addWidget(self.progress)
         progress_layout.addWidget(self.cancel_button)
@@ -263,7 +265,30 @@ class TorConnectionWidget(QtWidgets.QWidget):
     def _error_connecting_to_tor(self, msg):
         self.common.log("TorConnectionWidget", "_error_connecting_to_tor")
         self.active = False
-        self.fail.emit(msg)
+        # If we are allowed to try automatically resolving connection issues
+        # (e.g possible censorship) by obtaining bridges for the user, do so
+        if self.settings.get("censorship_circumvention"):
+            # Automatically try to obtain bridges from the Censorship Circumvention API
+            self.common.log("TorConnectionWidget", "_error_connecting_to_tor", "Trying to automatically obtain bridges")
+            self.meek.start()
+            self.censorship_circumvention = CensorshipCircumvention(self.common, self.meek)
+            request_bridges = self.censorship_circumvention.request_settings(country="cn")
+            if request_bridges:
+                # @TODO there might be several bridges
+                bridges = request_bridges["settings"][0]["bridges"]["bridge_strings"][0]
+                self.common.log("TorConnectionWidget", "_error_connecting_to_tor", f"Obtained bridges: {bridges}")
+                self.settings.set("bridges_enabled", True)
+                self.settings.set("bridges_type", "custom")
+                # @TODO there might be several bridges
+                self.settings.set("bridges_custom", bridges)
+                self.common.log("TorConnectionWidget", "_error_connecting_to_tor", "Starting Tor again")
+                self.settings.save()
+                # Now try and connect again
+                self.start()
+            else:
+                self.fail.emit()
+        else:
+            self.fail.emit()
 
 
 class TorConnectionThread(QtCore.QThread):

desktop/src/onionshare/tor_settings_tab.py

@@ -91,6 +91,12 @@ class TorSettingsTab(QtWidgets.QWidget):
         self.bridge_use_checkbox.stateChanged.connect(
             self.bridge_use_checkbox_state_changed
         )
+        self.censorship_circumvention_checkbox = QtWidgets.QCheckBox(
+            strings._("gui_settings_censorship_circumvention_checkbox")
+        )
+        self.censorship_circumvention_checkbox.stateChanged.connect(
+            self.censorship_circumvention_checkbox_state_changed
+        )
 
         # Built-in bridge
         self.bridge_builtin_radio = QtWidgets.QRadioButton(
@@ -164,6 +170,7 @@ class TorSettingsTab(QtWidgets.QWidget):
         bridges_layout = QtWidgets.QVBoxLayout()
         bridges_layout.addWidget(bridges_label)
         bridges_layout.addWidget(self.bridge_use_checkbox)
+        bridges_layout.addWidget(self.censorship_circumvention_checkbox)
         bridges_layout.addWidget(self.bridge_settings)
 
         self.bridges = QtWidgets.QWidget()
@@ -330,7 +337,7 @@ class TorSettingsTab(QtWidgets.QWidget):
         columns_wrapper.setLayout(columns_layout)
 
         # Tor connection widget
-        self.tor_con = TorConnectionWidget(self.common, self.status_bar)
+        self.tor_con = TorConnectionWidget(self.common, self.status_bar, self.meek)
         self.tor_con.success.connect(self.tor_con_success)
         self.tor_con.fail.connect(self.tor_con_fail)
         self.tor_con.hide()
@@ -430,6 +437,7 @@ class TorSettingsTab(QtWidgets.QWidget):
 
         if self.old_settings.get("bridges_enabled"):
             self.bridge_use_checkbox.setCheckState(QtCore.Qt.Checked)
+            self.censorship_circumvention_checkbox.setCheckState(QtCore.Qt.Checked)
             self.bridge_settings.show()
 
             bridges_type = self.old_settings.get("bridges_type")
@@ -506,6 +514,16 @@ class TorSettingsTab(QtWidgets.QWidget):
         else:
             self.bridge_settings.hide()
 
+    def censorship_circumvention_checkbox_state_changed(self, state):
+        """
+        'Allow censorship circumvention (automatic bridges)' checkbox changed
+        """
+        # Turning on censorship circumvention through the act of
+        # automatic bridge selection, implicitly means enabling
+        # bridges.
+        if state == QtCore.Qt.Checked:
+            self.bridge_use_checkbox.setCheckState(QtCore.Qt.Checked)
+
     def bridge_builtin_radio_toggled(self, checked):
         """
         'Select a built-in bridge' radio button toggled
@@ -812,6 +830,9 @@ class TorSettingsTab(QtWidgets.QWidget):
         if self.bridge_use_checkbox.checkState() == QtCore.Qt.Checked:
             settings.set("bridges_enabled", True)
 
+            if self.censorship_circumvention_checkbox.checkState() == QtCore.Qt.Checked:
+                settings.set("censorship_circumvention", True)
+
             if self.bridge_builtin_radio.isChecked():
                 settings.set("bridges_type", "built-in")