Ignore invalid URLs in QtWebEngine interceptor

Closes #4969

qutebrowser/api/qtutils.py

@@ -0,0 +1,23 @@
+# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
+
+# Copyright 2019 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
+#
+# This file is part of qutebrowser.
+#
+# qutebrowser is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# qutebrowser is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Utilities related to Qt classes."""
+
+# pylint: disable=unused-import
+from qutebrowser.utils.qtutils import ensure_valid

qutebrowser/browser/webengine/interceptor.py

@@ -150,6 +150,11 @@ class RequestInterceptor(QWebEngineUrlRequestInterceptor):
 
         url = info.requestUrl()
         first_party = info.firstPartyUrl()
+        if not url.isValid():
+            log.webview.debug("Ignoring invalid intercepted URL: {}".format(
+                url.errorString()))
+            return
+
         # Per QWebEngineUrlRequestInfo::ResourceType documentation, if we fail
         # our lookup, we should fall back to ResourceTypeUnknown
         try:

qutebrowser/components/adblock.py

@@ -31,7 +31,7 @@ import pathlib
 from PyQt5.QtCore import QUrl
 
 from qutebrowser.api import (cmdutils, hook, config, message, downloads,
-                             interceptor, apitypes)
+                             interceptor, apitypes, qtutils)
 
 
 logger = logging.getLogger('misc')
@@ -114,6 +114,8 @@ class HostBlocker:
         if first_party_url is not None and not first_party_url.isValid():
             first_party_url = None
 
+        qtutils.ensure_valid(request_url)
+
         if not config.get('content.host_blocking.enabled',
                           url=first_party_url):
             return False