Add Admin API capability to set adminship of a user (#5878)

Admin API: Set adminship of a user

changelog.d/5878.feature

@@ -0,0 +1 @@
+Add admin API endpoint for setting whether or not a user is a server administrator.

docs/admin_api/user_admin_api.rst

@@ -84,3 +84,23 @@ with a body of:
    }
 
 including an ``access_token`` of a server admin.
+
+
+Change whether a user is a server administrator or not
+======================================================
+
+Note that you cannot demote yourself.
+
+The api is::
+
+    PUT /_synapse/admin/v1/users/<user_id>/admin
+
+with a body of:
+
+.. code:: json
+
+    {
+        "admin": true
+    }
+
+including an ``access_token`` of a server admin.

synapse/handlers/admin.py

@@ -94,6 +94,16 @@ def search_users(self, term):
 
         return ret
 
+    def set_user_server_admin(self, user, admin):
+        """
+        Set the admin bit on a user.
+
+        Args:
+            user_id (UserID): the (necessarily local) user to manipulate
+            admin (bool): whether or not the user should be an admin of this server
+        """
+        return self.store.set_server_admin(user, admin)
+
     @defer.inlineCallbacks
     def export_user_data(self, user_id, writer):
         """Write all data we have on the user to the given writer.

synapse/rest/admin/__init__.py

@@ -44,6 +44,7 @@
 from synapse.rest.admin.media import register_servlets_for_media_repo
 from synapse.rest.admin.purge_room_servlet import PurgeRoomServlet
 from synapse.rest.admin.server_notice_servlet import SendServerNoticeServlet
+from synapse.rest.admin.users import UserAdminServlet
 from synapse.types import UserID, create_requester
 from synapse.util.versionstring import get_version_string
 
@@ -742,6 +743,7 @@ def register_servlets(hs, http_server):
     PurgeRoomServlet(hs).register(http_server)
     SendServerNoticeServlet(hs).register(http_server)
     VersionServlet(hs).register(http_server)
+    UserAdminServlet(hs).register(http_server)
 
 
 def register_servlets_for_client_rest_resource(hs, http_server):

synapse/rest/admin/users.py

@@ -0,0 +1,76 @@
+# -*- 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.
+import re
+
+from twisted.internet import defer
+
+from synapse.api.errors import SynapseError
+from synapse.http.servlet import (
+    RestServlet,
+    assert_params_in_dict,
+    parse_json_object_from_request,
+)
+from synapse.rest.admin import assert_requester_is_admin
+from synapse.types import UserID
+
+
+class UserAdminServlet(RestServlet):
+    """
+    Set whether or not a user is a server administrator.
+
+    Note that only local users can be server administrators, and that an
+    administrator may not demote themselves.
+
+    Only server administrators can use this API.
+
+    Example:
+        PUT /_synapse/admin/v1/users/@reivilibre:librepush.net/admin
+        {
+            "admin": true
+        }
+    """
+
+    PATTERNS = (re.compile("^/_synapse/admin/v1/users/(?P<user_id>@[^/]*)/admin$"),)
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.handlers = hs.get_handlers()
+
+    @defer.inlineCallbacks
+    def on_PUT(self, request, user_id):
+        yield assert_requester_is_admin(self.auth, request)
+        requester = yield self.auth.get_user_by_req(request)
+        auth_user = requester.user
+
+        target_user = UserID.from_string(user_id)
+
+        body = parse_json_object_from_request(request)
+
+        assert_params_in_dict(body, ["admin"])
+
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Only local users can be admins of this homeserver")
+
+        set_admin_to = bool(body["admin"])
+
+        if target_user == auth_user and not set_admin_to:
+            raise SynapseError(400, "You may not demote yourself.")
+
+        yield self.handlers.admin_handler.set_user_server_admin(
+            target_user, set_admin_to
+        )
+
+        return (200, {})

synapse/storage/registration.py

@@ -272,6 +272,14 @@ def delete_account_validity_for_user(self, user_id):
 
     @defer.inlineCallbacks
     def is_server_admin(self, user):
+        """Determines if a user is an admin of this homeserver.
+
+        Args:
+            user (UserID): user ID of the user to test
+
+        Returns (bool):
+            true iff the user is a server admin, false otherwise.
+        """
         res = yield self._simple_select_one_onecol(
             table="users",
             keyvalues={"name": user.to_string()},
@@ -282,6 +290,21 @@ def is_server_admin(self, user):
 
         return res if res else False
 
+    def set_server_admin(self, user, admin):
+        """Sets whether a user is an admin of this homeserver.
+
+        Args:
+            user (UserID): user ID of the user to test
+            admin (bool): true iff the user is to be a server admin,
+                false otherwise.
+        """
+        return self._simple_update_one(
+            table="users",
+            keyvalues={"name": user.to_string()},
+            updatevalues={"admin": 1 if admin else 0},
+            desc="set_server_admin",
+        )
+
     def _query_for_auth(self, txn, token):
         sql = (
             "SELECT users.name, users.is_guest, access_tokens.id as token_id,"