Merge pull request #4647 from matrix-org/erikj/add_room_publishing_rules

Add configurable room list publishing rules

3 files changed, 193 insertions, 31 deletions

diff --git a/synapse/config/room_directory.py b/synapse/config/room_directory.py
index 9da13ab11b..c8e0abbae7 100644
--- a/synapse/config/room_directory.py
+++ b/synapse/config/room_directory.py
@@ -20,12 +20,37 @@ from ._base import Config, ConfigError
 
 class RoomDirectoryConfig(Config):
     def read_config(self, config):
-        alias_creation_rules = config["alias_creation_rules"]
+        alias_creation_rules = config.get("alias_creation_rules")
 
-        self._alias_creation_rules = [
-            _AliasRule(rule)
-            for rule in alias_creation_rules
-        ]
+        if alias_creation_rules is not None:
+            self._alias_creation_rules = [
+                _RoomDirectoryRule("alias_creation_rules", rule)
+                for rule in alias_creation_rules
+            ]
+        else:
+            self._alias_creation_rules = [
+                _RoomDirectoryRule(
+                    "alias_creation_rules", {
+                        "action": "allow",
+                    }
+                )
+            ]
+
+        room_list_publication_rules = config.get("room_list_publication_rules")
+
+        if room_list_publication_rules is not None:
+            self._room_list_publication_rules = [
+                _RoomDirectoryRule("room_list_publication_rules", rule)
+                for rule in room_list_publication_rules
+            ]
+        else:
+            self._room_list_publication_rules = [
+                _RoomDirectoryRule(
+                    "room_list_publication_rules", {
+                        "action": "allow",
+                    }
+                )
+            ]
 
     def default_config(self, config_dir_path, server_name, **kwargs):
         return """
@@ -33,60 +58,138 @@ class RoomDirectoryConfig(Config):
         # on this server.
         #
         # The format of this option is a list of rules that contain globs that
-        # match against user_id and the new alias (fully qualified with server
-        # name). The action in the first rule that matches is taken, which can
-        # currently either be "allow" or "deny".
+        # match against user_id, room_id and the new alias (fully qualified with
+        # server name). The action in the first rule that matches is taken,
+        # which can currently either be "allow" or "deny".
+        #
+        # Missing user_id/room_id/alias fields default to "*".
+        #
+        # If no rules match the request is denied. An empty list means no one
+        # can create aliases.
+        #
+        # Options for the rules include:
+        #
+        #   user_id: Matches against the creator of the alias
+        #   alias: Matches against the alias being created
+        #   room_id: Matches against the room ID the alias is being pointed at
+        #   action: Whether to "allow" or "deny" the request if the rule matches
+        #
+        # The default is:
+        #
+        # alias_creation_rules:
+        #     - user_id: "*"
+        #       alias: "*"
+        #       room_id: "*"
+        #       action: allow
+
+        # The `room_list_publication_rules` option controls who can publish and
+        # which rooms can be published in the public room list.
+        #
+        # The format of this option is the same as that for
+        # `alias_creation_rules`.
         #
-        # If no rules match the request is denied.
-        alias_creation_rules:
-            - user_id: "*"
-              alias: "*"
-              action: allow
+        # If the room has one or more aliases associated with it, only one of
+        # the aliases needs to match the alias rule. If there are no aliases
+        # then only rules with `alias: *` match.
+        #
+        # If no rules match the request is denied. An empty list means no one
+        # can publish rooms.
+        #
+        # Options for the rules include:
+        #
+        #   user_id: Matches agaisnt the creator of the alias
+        #   room_id: Matches against the room ID being published
+        #   alias: Matches against any current local or canonical aliases
+        #            associated with the room
+        #   action: Whether to "allow" or "deny" the request if the rule matches
+        #
+        # The default is:
+        #
+        # room_list_publication_rules:
+        #     - user_id: "*"
+        #       alias: "*"
+        #       room_id: "*"
+        #       action: allow
         """
 
-    def is_alias_creation_allowed(self, user_id, alias):
+    def is_alias_creation_allowed(self, user_id, room_id, alias):
         """Checks if the given user is allowed to create the given alias
 
         Args:
             user_id (str)
+            room_id (str)
             alias (str)
 
         Returns:
             boolean: True if user is allowed to crate the alias
         """
         for rule in self._alias_creation_rules:
-            if rule.matches(user_id, alias):
+            if rule.matches(user_id, room_id, [alias]):
+                return rule.action == "allow"
+
+        return False
+
+    def is_publishing_room_allowed(self, user_id, room_id, aliases):
+        """Checks if the given user is allowed to publish the room
+
+        Args:
+            user_id (str)
+            room_id (str)
+            aliases (list[str]): any local aliases associated with the room
+
+        Returns:
+            boolean: True if user can publish room
+        """
+        for rule in self._room_list_publication_rules:
+            if rule.matches(user_id, room_id, aliases):
                 return rule.action == "allow"
 
         return False
 
 
-class _AliasRule(object):
-    def __init__(self, rule):
+class _RoomDirectoryRule(object):
+    """Helper class to test whether a room directory action is allowed, like
+    creating an alias or publishing a room.
+    """
+
+    def __init__(self, option_name, rule):
+        """
+        Args:
+            option_name (str): Name of the config option this rule belongs to
+            rule (dict): The rule as specified in the config
+        """
+
         action = rule["action"]
-        user_id = rule["user_id"]
-        alias = rule["alias"]
+        user_id = rule.get("user_id", "*")
+        room_id = rule.get("room_id", "*")
+        alias = rule.get("alias", "*")
 
         if action in ("allow", "deny"):
             self.action = action
         else:
             raise ConfigError(
-                "alias_creation_rules rules can only have action of 'allow'"
-                " or 'deny'"
+                "%s rules can only have action of 'allow'"
+                " or 'deny'" % (option_name,)
             )
 
+        self._alias_matches_all = alias == "*"
+
         try:
             self._user_id_regex = glob_to_regex(user_id)
             self._alias_regex = glob_to_regex(alias)
+            self._room_id_regex = glob_to_regex(room_id)
         except Exception as e:
             raise ConfigError("Failed to parse glob into regex: %s", e)
 
-    def matches(self, user_id, alias):
-        """Tests if this rule matches the given user_id and alias.
+    def matches(self, user_id, room_id, aliases):
+        """Tests if this rule matches the given user_id, room_id and aliases.
 
         Args:
             user_id (str)
-            alias (str)
+            room_id (str)
+            aliases (list[str]): The associated aliases to the room. Will be a
+                single element for testing alias creation, and can be empty for
+                testing room publishing.
 
         Returns:
             boolean
@@ -96,7 +199,22 @@ class _AliasRule(object):
         if not self._user_id_regex.match(user_id):
             return False
 
-        if not self._alias_regex.match(alias):
+        if not self._room_id_regex.match(room_id):
             return False
 
-        return True
+        # We only have alias checks left, so we can short circuit if the alias
+        # rule matches everything.
+        if self._alias_matches_all:
+            return True
+
+        # If we are not given any aliases then this rule only matches if the
+        # alias glob matches all aliases, which we checked above.
+        if not aliases:
+            return False
+
+        # Otherwise, we just need one alias to match
+        for alias in aliases:
+            if self._alias_regex.match(alias):
+                return True
+
+        return False
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 6bb254f899..8b113307d2 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -112,7 +112,9 @@ class DirectoryHandler(BaseHandler):
                     403, "This user is not permitted to create this alias",
                 )
 
-            if not self.config.is_alias_creation_allowed(user_id, room_alias.to_string()):
+            if not self.config.is_alias_creation_allowed(
+                user_id, room_id, room_alias.to_string(),
+            ):
                 # Lets just return a generic message, as there may be all sorts of
                 # reasons why we said no. TODO: Allow configurable error messages
                 # per alias creation rule?
@@ -395,9 +397,9 @@ class DirectoryHandler(BaseHandler):
         room_id (str)
         visibility (str): "public" or "private"
         """
-        if not self.spam_checker.user_may_publish_room(
-            requester.user.to_string(), room_id
-        ):
+        user_id = requester.user.to_string()
+
+        if not self.spam_checker.user_may_publish_room(user_id, room_id):
             raise AuthError(
                 403,
                 "This user is not permitted to publish rooms to the room list"
@@ -415,7 +417,24 @@ class DirectoryHandler(BaseHandler):
 
         yield self.auth.check_can_change_room_list(room_id, requester.user)
 
-        yield self.store.set_room_is_public(room_id, visibility == "public")
+        making_public = visibility == "public"
+        if making_public:
+            room_aliases = yield self.store.get_aliases_for_room(room_id)
+            canonical_alias = yield self.store.get_canonical_alias_for_room(room_id)
+            if canonical_alias:
+                room_aliases.append(canonical_alias)
+
+            if not self.config.is_publishing_room_allowed(
+                user_id, room_id, room_aliases,
+            ):
+                # Lets just return a generic message, as there may be all sorts of
+                # reasons why we said no. TODO: Allow configurable error messages
+                # per alias creation rule?
+                raise SynapseError(
+                    403, "Not allowed to publish room",
+                )
+
+        yield self.store.set_room_is_public(room_id, making_public)
 
     @defer.inlineCallbacks
     def edit_published_appservice_room_list(self, appservice_id, network_id,
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index d14a7b2538..6ddc4055d2 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -548,6 +548,31 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             _get_filtered_current_state_ids_txn,
         )
 
+    @defer.inlineCallbacks
+    def get_canonical_alias_for_room(self, room_id):
+        """Get canonical alias for room, if any
+
+        Args:
+            room_id (str)
+
+        Returns:
+            Deferred[str|None]: The canonical alias, if any
+        """
+
+        state = yield self.get_filtered_current_state_ids(room_id, StateFilter.from_types(
+            [(EventTypes.CanonicalAlias, "")]
+        ))
+
+        event_id = state.get((EventTypes.CanonicalAlias, ""))
+        if not event_id:
+            return
+
+        event = yield self.get_event(event_id, allow_none=True)
+        if not event:
+            return
+
+        defer.returnValue(event.content.get("canonical_alias"))
+
     @cached(max_entries=10000, iterable=True)
     def get_state_group_delta(self, state_group):
         """Given a state group try to return a previous group and a delta between