ui: improved DefaultAction behaviour

- On the very first install, or if the GUI's settings.conf file was not
  created, GUI's DefaultAction item was not configured properly.
- Now when the daemon is not connected to the GUI, it'll use the
  DefaultAction configured in /etc/opensnitchd/default-config.json
- When the daemon is connected to the GUI, the GUI will reconfigure
  daemon's DefaultAction value when the one defined by the GUI.
  In this case the value defined in default-config.json is not modified,
  it'll only be valid while it's connected to the GUI.

Now when opening Preferences->Nodes, it'll display daemon's
DefaultAction defined in the file default-config.json file, which is the
default action applied when the daemon is not connected to the GUI.

Related: #884 , #896

ui/opensnitch/config.py

@@ -147,7 +147,7 @@ def __init__(self):
         if self.settings.value(self.DEFAULT_TIMEOUT_KEY) == None:
             self.setSettings(self.DEFAULT_TIMEOUT_KEY, self.DEFAULT_TIMEOUT)
         if self.settings.value(self.DEFAULT_ACTION_KEY) == None:
-            self.setSettings(self.DEFAULT_ACTION_KEY, self.ACTION_ALLOW)
+            self.setSettings(self.DEFAULT_ACTION_KEY, self.ACTION_DENY_IDX)
         if self.settings.value(self.DEFAULT_DURATION_KEY) == None:
             self.setSettings(self.DEFAULT_DURATION_KEY, self.DEFAULT_DURATION_IDX)
         if self.settings.value(self.DEFAULT_TARGET_KEY) == None:

ui/opensnitch/service.py

@@ -6,6 +6,7 @@
 import os
 import sys
 import json
+import copy
 
 path = os.path.abspath(os.path.dirname(__file__))
 sys.path.append(path)
@@ -592,19 +593,24 @@ def _populate_stats_events(self, db, addr, stats, table, colnames, cols, items):
         return need_refresh
 
     def _overwrite_nodes_config(self, node_config):
+        """Overwrite daemon's DefaultAction value, with the one defined by the GUI.
+        It'll only be valid while the daemon is connected to the GUI (it's not saved to disk).
+        """
+        newconf = copy.deepcopy(node_config)
         _default_action = self._cfg.getInt(self._cfg.DEFAULT_ACTION_KEY)
-        temp_cfg = json.loads(node_config)
         try:
+            temp_cfg = json.loads(newconf.config)
             if _default_action == Config.ACTION_DENY_IDX:
                 temp_cfg['DefaultAction'] = Config.ACTION_DENY
             else:
                 temp_cfg['DefaultAction'] = Config.ACTION_ALLOW
 
-            node_config = json.dumps(temp_cfg)
+            newconf.config = json.dumps(temp_cfg)
         except Exception as e:
             print("error parsing node's configuration:", e)
+            return node_config
 
-        return node_config
+        return newconf
 
     @QtCore.pyqtSlot(dict)
     def _on_node_actions(self, kwargs):
@@ -750,9 +756,9 @@ def Subscribe(self, node_config, context):
             print("[Notifications] exception adding new node:", e)
             context.cancel()
 
-        node_config.config = self._overwrite_nodes_config(node_config.config)
+        newconf = self._overwrite_nodes_config(node_config)
 
-        return node_config
+        return newconf
 
     def Notifications(self, node_iter, context):
         """