ui: restrict allowed characters in the rule name

Since the name of the rule is used for the file name on the disk,
certain characters caused issues when saving the rule, like '/'.

Now if the user types or pastes '/' in the name field, a warning is
displayed, indicating that some characters are not allowed.

Closes #1166

ui/opensnitch/dialogs/ruleseditor.py

@@ -16,7 +16,13 @@ from opensnitch.nodes import Nodes
 from opensnitch.database import Database
 from opensnitch.database.enums import RuleFields, ConnFields
 from opensnitch.version import version
-from opensnitch.utils import Message, FileDialog, Icons, NetworkInterfaces
+from opensnitch.utils import (
+    Message,
+    FileDialog,
+    Icons,
+    NetworkInterfaces,
+    qvalidator
+)
 from opensnitch.rules import Rule, Rules
 
 DIALOG_UI_PATH = "%s/../res/ruleseditor.ui" % os.path.dirname(sys.modules[__name__].__file__)
@@ -33,6 +39,8 @@ class RulesEditorDialog(QtWidgets.QDialog, uic.loadUiType(DIALOG_UI_PATH)[0]):
     LAN_LABEL = "LAN"
     MULTICAST_LABEL = "MULTICAST"
 
+    INVALID_RULE_NAME_CHARS = '/'
+
     ADD_RULE = 0
     EDIT_RULE = 1
     WORK_MODE = ADD_RULE
@@ -55,6 +63,10 @@ class RulesEditorDialog(QtWidgets.QDialog, uic.loadUiType(DIALOG_UI_PATH)[0]):
         self.setupUi(self)
         self.setWindowIcon(appicon)
 
+        self.ruleNameValidator = qvalidator.RestrictChars(RulesEditorDialog.INVALID_RULE_NAME_CHARS)
+        self.ruleNameValidator.result.connect(self._cb_rule_name_validator_result)
+        self.ruleNameEdit.setValidator(self.ruleNameValidator)
+
         self.buttonBox.setStandardButtons(
             QtWidgets.QDialogButtonBox.Help |
             QtWidgets.QDialogButtonBox.Reset |
@@ -139,6 +151,16 @@ class RulesEditorDialog(QtWidgets.QDialog, uic.loadUiType(DIALOG_UI_PATH)[0]):
     def _bool(self, s):
         return s == 'True'
 
+    def _cb_rule_name_validator_result(self, result):
+        if result == QtGui.QValidator.Invalid:
+            self._set_status_error(
+                QC.translate("rules",
+                             "Invalid rule name (not allowed characters: '{0}' )".format(RulesEditorDialog.INVALID_RULE_NAME_CHARS)
+                             )
+            )
+        else:
+            self._set_status_message("")
+
     def _cb_accept_clicked(self):
         pass
 

ui/opensnitch/utils/qvalidator.py

@@ -0,0 +1,25 @@
+
+from PyQt5 import QtCore, QtGui
+
+class RestrictChars(QtGui.QValidator):
+    result = QtCore.pyqtSignal(object)
+
+    def __init__(self, restricted_chars, *args, **kwargs):
+        QtGui.QValidator.__init__(self, *args, **kwargs)
+        self._restricted_chars = restricted_chars
+
+    def validate(self, value, pos):
+        # allow to delete all characters
+        if len(value) == 0:
+            return QtGui.QValidator.Intermediate, value, pos
+
+        # user can type characters or paste them.
+        # pos value when pasting can be any number, depending on where did the
+        # user paste the characters.
+        for char in self._restricted_chars:
+            if char in value:
+                self.result.emit(QtGui.QValidator.Invalid)
+                return QtGui.QValidator.Invalid, value, pos
+
+        self.result.emit(QtGui.QValidator.Acceptable)
+        return QtGui.QValidator.Acceptable, value, pos