diff --git a/event-schemas/schema/core-event-schema/state_event.yaml b/event-schemas/schema/core-event-schema/state_event.yaml index 020e9087..71c4137b 100644 --- a/event-schemas/schema/core-event-schema/state_event.yaml +++ b/event-schemas/schema/core-event-schema/state_event.yaml @@ -11,7 +11,11 @@ properties: state_key: description: A unique key which defines the overwriting semantics for this piece of room state. This value is often a zero-length string. The presence of this - key makes this event a State Event. The key MUST NOT start with '_'. + key makes this event a State Event. + + State keys starting with an ``@`` are reserved for referencing user IDs, such + as room members. With the exception of a few events, state events set with a + given user's ID as the state key MUST only be set by that user. type: string required: - state_key diff --git a/event-schemas/schema/m.room.member b/event-schemas/schema/m.room.member index 5fb5356d..de14644d 100644 --- a/event-schemas/schema/m.room.member +++ b/event-schemas/schema/m.room.member @@ -105,7 +105,10 @@ properties: title: EventContent type: object state_key: - description: The ``user_id`` this membership event relates to. + description: |- + The ``user_id`` this membership event relates to. In all cases except for when ``membership`` is + ``join``, the user ID sending the event does not need to match the user ID in the ``state_key``, + unlike other events. Regular authorisation rules still apply. type: string type: enum: diff --git a/specification/server_server_api.rst b/specification/server_server_api.rst index 439b35f9..a66f249c 100644 --- a/specification/server_server_api.rst +++ b/specification/server_server_api.rst @@ -450,7 +450,10 @@ The rules are as follows: #. Otherwise, reject. -7. Otherwise, allow. +7. If the ``state_key`` starts with ``@`` and the ``state_key`` does not match + the ``sender``, reject. + +8. Otherwise, allow. .. NOTE::