From 1ce00f90fea3f1f078e22387442087c5ca7329b0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timo=20K=C3=B6sters?= <timo@koesters.xyz>
Date: Thu, 4 Mar 2021 13:36:06 +0100
Subject: [PATCH] fix: don't accept incoming pdus if we know about them already

---
 src/server_server.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/server_server.rs b/src/server_server.rs
index 00f31ca3..d5898182 100644
--- a/src/server_server.rs
+++ b/src/server_server.rs
@@ -554,6 +554,12 @@ pub async fn send_transaction_message_route<'a>(
         // TODO: redact event if hashing fails
         let (event_id, value) = crate::pdu::process_incoming_pdu(pdu);
 
+        // Skip the pdu if we already know about it
+        if db.rooms.get_pdu_id(&event_id)?.is_some() {
+            resolved_map.insert(event_id, Err("We already know about this event".into()));
+            continue;
+        }
+
         let pdu = serde_json::from_value::<PduEvent>(
             serde_json::to_value(&value).expect("CanonicalJsonObj is a valid JsonValue"),
         )