privacy by default for room dir (#6355)

Ensure that the the default settings for the room directory are that the it is hidden from public view by default.

UPGRADE.rst

@@ -75,6 +75,23 @@ for example:
      wget https://packages.matrix.org/debian/pool/main/m/matrix-synapse-py3/matrix-synapse-py3_1.3.0+stretch1_amd64.deb
      dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
 
+Upgrading to v1.7.0
+===================
+
+In an attempt to configure Synapse in a privacy preserving way, the default
+behaviours of ``allow_public_rooms_without_auth`` and
+``allow_public_rooms_over_federation`` have been inverted. This means that by
+default, only authenticated users querying the Client/Server API will be able
+to query the room directory, and relatedly that the server will not share
+room directory information with other servers over federation.
+
+If your installation does not explicitly set these settings one way or the other
+and you want either setting to be ``true`` then it will necessary to update
+your homeserver configuration file accordingly.
+
+For more details on the surrounding context see our `explainer
+<https://matrix.org/blog/2019/11/09/avoiding-unwelcome-visitors-on-private-matrix-servers>`_.
+
 
 Upgrading to v1.5.0
 ===================

changelog.d/6354.feature

@@ -0,0 +1 @@
+Configure privacy preserving settings by default for the room directory.

docs/sample_config.yaml

@@ -54,15 +54,16 @@ pid_file: DATADIR/homeserver.pid
 #
 #require_auth_for_profile_requests: true
 
-# If set to 'false', requires authentication to access the server's public rooms
-# directory through the client API. Defaults to 'true'.
+# If set to 'true', removes the need for authentication to access the server's
+# public rooms directory through the client API, meaning that anyone can
+# query the room directory. Defaults to 'false'.
 #
-#allow_public_rooms_without_auth: false
+#allow_public_rooms_without_auth: true
 
-# If set to 'false', forbids any other homeserver to fetch the server's public
-# rooms directory via federation. Defaults to 'true'.
+# If set to 'true', allows any other homeserver to fetch the server's public
+# rooms directory via federation. Defaults to 'false'.
 #
-#allow_public_rooms_over_federation: false
+#allow_public_rooms_over_federation: true
 
 # The default room version for newly created rooms.
 #

synapse/config/server.py

@@ -118,15 +118,16 @@ class ServerConfig(Config):
             self.allow_public_rooms_without_auth = False
             self.allow_public_rooms_over_federation = False
         else:
-            # If set to 'False', requires authentication to access the server's public
-            # rooms directory through the client API. Defaults to 'True'.
+            # If set to 'true', removes the need for authentication to access the server's
+            # public rooms directory through the client API, meaning that anyone can
+            # query the room directory. Defaults to 'false'.
             self.allow_public_rooms_without_auth = config.get(
-                "allow_public_rooms_without_auth", True
+                "allow_public_rooms_without_auth", False
             )
-            # If set to 'False', forbids any other homeserver to fetch the server's public
-            # rooms directory via federation. Defaults to 'True'.
+            # If set to 'true', allows any other homeserver to fetch the server's public
+            # rooms directory via federation. Defaults to 'false'.
             self.allow_public_rooms_over_federation = config.get(
-                "allow_public_rooms_over_federation", True
+                "allow_public_rooms_over_federation", False
             )
 
         default_room_version = config.get("default_room_version", DEFAULT_ROOM_VERSION)
@@ -620,15 +621,16 @@ class ServerConfig(Config):
         #
         #require_auth_for_profile_requests: true
 
-        # If set to 'false', requires authentication to access the server's public rooms
-        # directory through the client API. Defaults to 'true'.
+        # If set to 'true', removes the need for authentication to access the server's
+        # public rooms directory through the client API, meaning that anyone can
+        # query the room directory. Defaults to 'false'.
         #
-        #allow_public_rooms_without_auth: false
+        #allow_public_rooms_without_auth: true
 
-        # If set to 'false', forbids any other homeserver to fetch the server's public
-        # rooms directory via federation. Defaults to 'true'.
+        # If set to 'true', allows any other homeserver to fetch the server's public
+        # rooms directory via federation. Defaults to 'false'.
         #
-        #allow_public_rooms_over_federation: false
+        #allow_public_rooms_over_federation: true
 
         # The default room version for newly created rooms.
         #

tests/federation/transport/test_server.py

@@ -0,0 +1,52 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+from twisted.internet import defer
+
+from synapse.config.ratelimiting import FederationRateLimitConfig
+from synapse.federation.transport import server
+from synapse.util.ratelimitutils import FederationRateLimiter
+
+from tests import unittest
+from tests.unittest import override_config
+
+
+class RoomDirectoryFederationTests(unittest.HomeserverTestCase):
+    def prepare(self, reactor, clock, homeserver):
+        class Authenticator(object):
+            def authenticate_request(self, request, content):
+                return defer.succeed("otherserver.nottld")
+
+        ratelimiter = FederationRateLimiter(clock, FederationRateLimitConfig())
+        server.register_servlets(
+            homeserver, self.resource, Authenticator(), ratelimiter
+        )
+
+    @override_config({"allow_public_rooms_over_federation": False})
+    def test_blocked_public_room_list_over_federation(self):
+        request, channel = self.make_request(
+            "GET", "/_matrix/federation/v1/publicRooms"
+        )
+        self.render(request)
+        self.assertEquals(403, channel.code)
+
+    @override_config({"allow_public_rooms_over_federation": True})
+    def test_open_public_room_list_over_federation(self):
+        request, channel = self.make_request(
+            "GET", "/_matrix/federation/v1/publicRooms"
+        )
+        self.render(request)
+        self.assertEquals(200, channel.code)