Add webrtc_ip_handling_policy setting

This exposes all possible values, but before
https://codereview.qt-project.org/#/c/240121/ we won't be able to change those
at runtime (or enable URL patterns, which thankfully weren't enabled for the
old setting).

In theory, it'd be possible to handle the "public-interface-only" value via
QWebEngineSettings without requiring a restart, but it isn't worth the trouble.

Closes #4201

doc/changelog.asciidoc

@@ -36,6 +36,8 @@ Added
   model.
 - New `qt.low_end_device_mode` setting which turns on Chromium's low-end device
   mode. This mode uses less RAM, but the expense of performance.
+- New `content.webrtc_ip_handling_policy` setting, which allows more
+  fine-grained/restrictive control about which IPs are exposed via WebRTC.
 
 Changed
 ~~~~~~~
@@ -71,6 +73,8 @@ Removed
 ~~~~~~~
 
 - Support for importing pre-v1.0.0 history files has been removed.
+- The `content.webrtc_public_interfaces_only` setting has been removed and
+  replaced by `content.webrtc_ip_handling_policy`.
 
 v1.4.2
 ------

doc/help/settings.asciidoc

@@ -158,7 +158,7 @@
 |<<content.ssl_strict,content.ssl_strict>>|Validate SSL handshakes.
 |<<content.user_stylesheets,content.user_stylesheets>>|List of user stylesheet filenames to use.
 |<<content.webgl,content.webgl>>|Enable WebGL.
-|<<content.webrtc_public_interfaces_only,content.webrtc_public_interfaces_only>>|Only expose public interfaces via WebRTC.
+|<<content.webrtc_ip_handling_policy,content.webrtc_ip_handling_policy>>|Which interfaces to expose via WebRTC.
 |<<content.windowed_fullscreen,content.windowed_fullscreen>>|Limit fullscreen to the browser window (does not expand to fill the screen).
 |<<content.xss_auditing,content.xss_auditing>>|Monitor load requests for cross-site scripting attempts.
 |<<downloads.location.directory,downloads.location.directory>>|Directory to save downloads to.
@@ -2073,14 +2073,22 @@ Type: <<types,Bool>>
 
 Default: +pass:[true]+
 
-[[content.webrtc_public_interfaces_only]]
-=== content.webrtc_public_interfaces_only
-Only expose public interfaces via WebRTC.
-On Qt 5.9, this option requires a restart. On Qt 5.10, this option doesn't work at all because of a Qt bug. On Qt >= 5.11, no restart is required.
+[[content.webrtc_ip_handling_policy]]
+=== content.webrtc_ip_handling_policy
+Which interfaces to expose via WebRTC.
+On Qt 5.10, this option doesn't work because of a Qt bug.
+This setting requires a restart.
 
-Type: <<types,Bool>>
+Type: <<types,String>>
 
-Default: +pass:[false]+
+Valid values:
+
+ * +all-interfaces+: WebRTC has the right to enumerate all interfaces and bind them to discover public interfaces.
+ * +default-public-and-private-interfaces+: WebRTC should only use the default route used by http. This also exposes the associated default private address. Default route is the route chosen by the OS on a multi-homed endpoint.
+ * +default-public-interface-only+: WebRTC should only use the default route used by http. This doesn't expose any local addresses.
+ * +disable-non-proxied-udp+: WebRTC should only use TCP to contact peers or servers unless the proxy server supports UDP. This doesn't expose any local addresses either.
+
+Default: +pass:[all-interfaces]+
 
 On QtWebEngine, this setting requires Qt 5.9.2 or newer.
 

qutebrowser/browser/webengine/webenginesettings.py

@@ -166,8 +166,6 @@ class WebEngineSettings(websettings.AbstractSettings):
             # Qt 5.11
             'content.autoplay':
                 ('PlaybackRequiresUserGesture', lambda val: not val),
-            'content.webrtc_public_interfaces_only':
-                ('WebRTCPublicInterfacesOnly', None),
         }
         for name, (attribute, converter) in new_attributes.items():
             try:

qutebrowser/config/configdata.yml

@@ -769,18 +769,31 @@ content.webgl:
   supports_pattern: true
   desc: Enable WebGL.
 
-content.webrtc_public_interfaces_only:
-  default: false
-  type: Bool
+content.webrtc_ip_handling_policy:
+  default: all-interfaces
+  type:
+    name: String
+    valid_values:
+      - all-interfaces: WebRTC has the right to enumerate all interfaces and
+            bind them to discover public interfaces.
+      - default-public-and-private-interfaces: WebRTC should only use the
+            default route used by http. This also exposes the associated
+            default private address. Default route is the route chosen by the
+            OS on a multi-homed endpoint.
+      - default-public-interface-only: WebRTC should only use the default route
+            used by http. This doesn't expose any local addresses.
+      - disable-non-proxied-udp: WebRTC should only use TCP to contact peers or
+            servers unless the proxy server supports UDP. This doesn't expose
+            any local addresses either.
+  default: all-interfaces
   backend:
     QtWebKit: false
     QtWebEngine: Qt 5.9.2
+  restart: true
   desc: >-
-    Only expose public interfaces via WebRTC.
+    Which interfaces to expose via WebRTC.
 
-    On Qt 5.9, this option requires a restart.
-    On Qt 5.10, this option doesn't work at all because of a Qt bug.
-    On Qt >= 5.11, no restart is required.
+    On Qt 5.10, this option doesn't work because of a Qt bug.
 
 content.xss_auditing:
   type: Bool

qutebrowser/config/configfiles.py

@@ -276,6 +276,21 @@ class YamlConfig(QObject):
             del settings['bindings.default']
             self._mark_changed()
 
+        # content.webrtc_public_interfaces_only got merged into
+        # content.webrtc_ip_handling_policy.
+        old = 'content.webrtc_public_interfaces_only'
+        new = 'content.webrtc_ip_handling_policy'
+        if old in settings:
+            settings[new] = {}
+            for scope, val in settings[old].items():
+                if val:
+                    settings[new][scope] = 'default-public-interface-only'
+                else:
+                    settings[new][scope] = 'all-interfaces'
+
+            del settings[old]
+            self._mark_changed()
+
         self._migrate_bool(settings, 'tabs.favicons.show', 'always', 'never')
         self._migrate_bool(settings, 'qt.force_software_rendering',
                            'software-opengl', 'none')

qutebrowser/config/configinit.py

@@ -187,9 +187,11 @@ def qt_args(namespace):
             # On Qt 5.11, we can control this via QWebEngineSettings
             if not config.val.content.autoplay:
                 argv.append('--autoplay-policy=user-gesture-required')
-            if config.val.content.webrtc_public_interfaces_only:
-                argv.append('--force-webrtc-ip-handling-policy='
-                            'default_public_interface_only')
+
+        webrtc_policy = config.val.content.webrtc_ip_handling_policy
+        if webrtc_policy != 'all-interfaces':
+            argv.append('--force-webrtc-ip-handling-policy=' +
+                        webrtc_policy.replace('-', '_'))
 
         process_model = config.val.qt.process_model
         if process_model == 'process-per-site-instance':

tests/unit/config/test_configfiles.py

@@ -235,6 +235,21 @@ class TestYaml:
         data = autoconfig.read()
         assert 'bindings.default' not in data
 
+    @pytest.mark.parametrize('public_only, expected', [
+        (True, 'default-public-interface-only'),
+        (False, 'all-interfaces'),
+    ])
+    def test_webrtc(self, yaml, autoconfig, public_only, expected):
+        """Tests for migration of content.webrtc_public_interfaces_only."""
+        autoconfig.write({'content.webrtc_public_interfaces_only':
+                          {'global': public_only}})
+
+        yaml.load()
+        yaml._save()
+
+        data = autoconfig.read()
+        assert data['content.webrtc_ip_handling_policy']['global'] == expected
+
     @pytest.mark.parametrize('show, expected', [
         (True, 'always'),
         (False, 'never'),

tests/unit/config/test_configinit.py

@@ -438,23 +438,35 @@ class TestQtArgs:
         assert ('--autoplay-policy=user-gesture-required' in args) == added
 
     @utils.qt59
-    @pytest.mark.parametrize('new_version, public_only, added', [
-        (True, True, False),  # new enough to not need it
-        (False, False, False),  # option disabled
-        (False, True, True),
+    @pytest.mark.parametrize('policy, arg', [
+        ('all-interfaces', None),
+
+        ('default-public-and-private-interfaces',
+         '--force-webrtc-ip-handling-policy='
+         'default_public_and_private_interfaces'),
+
+        ('default-public-interface-only',
+         '--force-webrtc-ip-handling-policy='
+         'default_public_interface_only'),
+
+        ('disable-non-proxied-udp',
+         '--force-webrtc-ip-handling-policy='
+         'disable_non_proxied_udp'),
     ])
     def test_webrtc(self, config_stub, monkeypatch, parser,
-                    new_version, public_only, added):
+                    policy, arg):
         monkeypatch.setattr(configinit.objects, 'backend',
                             usertypes.Backend.QtWebEngine)
-        config_stub.val.content.webrtc_public_interfaces_only = public_only
-        monkeypatch.setattr(configinit.qtutils, 'version_check',
-                            lambda version, compiled=False: new_version)
+        config_stub.val.content.webrtc_ip_handling_policy = policy
 
         parsed = parser.parse_args([])
         args = configinit.qt_args(parsed)
-        arg = '--force-webrtc-ip-handling-policy=default_public_interface_only'
-        assert (arg in args) == added
+
+        if arg is None:
+            assert not any(a.startswith('--force-webrtc-ip-handling-policy=')
+                           for a in args)
+        else:
+            assert arg in args
 
     @pytest.mark.parametrize('canvas_reading, added', [
         (True, False),  # canvas reading enabled