add options to require an access_token to GET /profile and /publicRooms on CS API (#5083)

This commit adds two config options:

* `restrict_public_rooms_to_local_users`

Requires auth to fetch the public rooms directory through the CS API and disables fetching it through the federation API.

* `require_auth_for_profile_requests`

When set to `true`, requires that requests to `/profile` over the CS API are authenticated, and only returns the user's profile if the requester shares a room with the profile's owner, as per MSC1301.

MSC1301 also specifies a behaviour for federation (only returning the profile if the server asking for it shares a room with the profile's owner), but that's currently really non-trivial to do in a not too expensive way. Next step is writing down a MSC that allows a HS to specify which user sent the profile query. In this implementation, Synapse won't send a profile query over federation if it doesn't believe it already shares a room with the profile's owner, though.

Groups have been intentionally omitted from this commit.

1 files changed, 10 insertions, 0 deletions

diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 452599e1a1..9030eb18c5 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -716,8 +716,17 @@ class PublicRoomList(BaseFederationServlet):
 
     PATH = "/publicRooms"
 
+    def __init__(self, handler, authenticator, ratelimiter, server_name, deny_access):
+        super(PublicRoomList, self).__init__(
+            handler, authenticator, ratelimiter, server_name,
+        )
+        self.deny_access = deny_access
+
     @defer.inlineCallbacks
     def on_GET(self, origin, content, query):
+        if self.deny_access:
+            raise FederationDeniedError(origin)
+
         limit = parse_integer_from_args(query, "limit", 0)
         since_token = parse_string_from_args(query, "since", None)
         include_all_networks = parse_boolean_from_args(
@@ -1417,6 +1426,7 @@ def register_servlets(hs, resource, authenticator, ratelimiter, servlet_groups=N
                 authenticator=authenticator,
                 ratelimiter=ratelimiter,
                 server_name=hs.hostname,
+                deny_access=hs.config.restrict_public_rooms_to_local_users,
             ).register(resource)
 
     if "group_server" in servlet_groups: