1 files changed, 43 insertions, 0 deletions
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index a65c98ff5c..91fc718ff8 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -53,6 +53,7 @@ class BaseProfileHandler(BaseHandler):
     @defer.inlineCallbacks
     def get_profile(self, user_id):
         target_user = UserID.from_string(user_id)
+
         if self.hs.is_mine(target_user):
             try:
                 displayname = yield self.store.get_profile_displayname(
@@ -283,6 +284,48 @@ class BaseProfileHandler(BaseHandler):
                     room_id, str(e)
                 )
 
+    @defer.inlineCallbacks
+    def check_profile_query_allowed(self, target_user, requester=None):
+        """Checks whether a profile query is allowed. If the
+        'require_auth_for_profile_requests' config flag is set to True and a
+        'requester' is provided, the query is only allowed if the two users
+        share a room.
+
+        Args:
+            target_user (UserID): The owner of the queried profile.
+            requester (None|UserID): The user querying for the profile.
+
+        Raises:
+            SynapseError(403): The two users share no room, or ne user couldn't
+                be found to be in any room the server is in, and therefore the query
+                is denied.
+        """
+        # Implementation of MSC1301: don't allow looking up profiles if the
+        # requester isn't in the same room as the target. We expect requester to
+        # be None when this function is called outside of a profile query, e.g.
+        # when building a membership event. In this case, we must allow the
+        # lookup.
+        if not self.hs.config.require_auth_for_profile_requests or not requester:
+            return
+
+        try:
+            requester_rooms = yield self.store.get_rooms_for_user(
+                requester.to_string()
+            )
+            target_user_rooms = yield self.store.get_rooms_for_user(
+                target_user.to_string(),
+            )
+
+            # Check if the room lists have no elements in common.
+            if requester_rooms.isdisjoint(target_user_rooms):
+                raise SynapseError(403, "Profile isn't available", Codes.FORBIDDEN)
+        except StoreError as e:
+            if e.code == 404:
+                # This likely means that one of the users doesn't exist,
+                # so we act as if we couldn't find the profile.
+                raise SynapseError(403, "Profile isn't available", Codes.FORBIDDEN)
+            raise
+
 
 class MasterProfileHandler(BaseProfileHandler):
     PROFILE_UPDATE_MS = 60 * 1000