fixed regexp rules exceptions

- ui, ruleseditor: added missing operator when using a regular
  expression on the DstIP/Net field.
- daemon, rules: ensure that regular expressions are of type string
  before evaluating them.

reported here: #333

daemon/rule/operator.go

@@ -3,6 +3,7 @@ package rule
 import (
 	"fmt"
 	"net"
+	"reflect"
 	"regexp"
 	"strings"
 
@@ -122,6 +123,10 @@ func (o *Operator) simpleCmp(v interface{}) bool {
 }
 
 func (o *Operator) reCmp(v interface{}) bool {
+	if vt := reflect.ValueOf(v).Kind(); vt != reflect.String {
+		log.Warning("Operator.reCmp() bad interface type: %T", v)
+		return false
+	}
 	if o.Sensitive == false {
 		v = strings.ToLower(v.(string))
 	}

ui/opensnitch/dialogs/ruleseditor.py

@@ -450,6 +450,7 @@ class RulesEditorDialog(QtWidgets.QDialog, uic.loadUiType(DIALOG_UI_PATH)[0]):
                     self.rule.operator.type = "network"
 
                 if self._is_regex(dstIPtext):
+                    self.rule.operator.operand = "dest.ip"
                     self.rule.operator.type = "regexp"
                     if self._is_valid_regex(self.dstIPCombo.currentText()) == False:
                         return False, QtCore.QCoreApplication.translate("rules", "Dst IP regexp error")