From 80adf46d5ffbd826daa246cb7c8c73e258dcbf92 Mon Sep 17 00:00:00 2001
From: nexy7574 <git@nexy7574.co.uk>
Date: Sat, 7 Jun 2025 00:46:55 +0100
Subject: [PATCH] fix an auth rule not applying correctly

---
 src/core/matrix/state_res/event_auth.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/core/matrix/state_res/event_auth.rs b/src/core/matrix/state_res/event_auth.rs
index 77a4a95c..ca266c5c 100644
--- a/src/core/matrix/state_res/event_auth.rs
+++ b/src/core/matrix/state_res/event_auth.rs
@@ -256,6 +256,16 @@ where
 		},
 		| Some(e) => e,
 	};
+	// just re-check 1.2 to work around a bug
+	let Some(room_id_server_name) = incoming_event.room_id().server_name() else {
+		warn!("room ID has no servername");
+		return Ok(false);
+	};
+
+	if room_id_server_name != sender.server_name() {
+		warn!("servername of room ID does not match servername of m.room.create sender");
+		return Ok(false);
+	}
 
 	if incoming_event.room_id() != room_create_event.room_id() {
 		warn!("room_id of incoming event does not match room_id of m.room.create event");