From 3db1377b261eaf3fcff486547d6302ccb24553e5 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 23 Jul 2019 13:31:03 +0100
Subject: [PATCH 1/3] Log when we receive receipt from a different origin

---
 synapse/handlers/receipts.py | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index a85dd8cdee69..e58bf7e360bf 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -17,7 +17,7 @@
 from twisted.internet import defer
 
 from synapse.handlers._base import BaseHandler
-from synapse.types import ReadReceipt
+from synapse.types import ReadReceipt, get_domain_from_id
 
 logger = logging.getLogger(__name__)
 
@@ -40,18 +40,27 @@ def __init__(self, hs):
     def _received_remote_receipt(self, origin, content):
         """Called when we receive an EDU of type m.receipt from a remote HS.
         """
-        receipts = [
-            ReadReceipt(
-                room_id=room_id,
-                receipt_type=receipt_type,
-                user_id=user_id,
-                event_ids=user_values["event_ids"],
-                data=user_values.get("data", {}),
-            )
-            for room_id, room_values in content.items()
-            for receipt_type, users in room_values.items()
-            for user_id, user_values in users.items()
-        ]
+        receipts = []
+        for room_id, room_values in content.items():
+            for receipt_type, users in room_values.items():
+                for user_id, user_values in users.items():
+                    if get_domain_from_id(user_id) != origin:
+                        logger.info(
+                            "Received receipt for user %r from server %s, ignoring",
+                            user_id,
+                            origin,
+                        )
+                        continue
+
+                    receipts.append(
+                        ReadReceipt(
+                            room_id=room_id,
+                            receipt_type=receipt_type,
+                            user_id=user_id,
+                            event_ids=user_values["event_ids"],
+                            data=user_values.get("data", {}),
+                        )
+                    )
 
         yield self._handle_new_receipts(receipts)
 

From fadfde9aaaf37da6b3f8f4ca27a028f43cc8a3f3 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 23 Jul 2019 13:32:37 +0100
Subject: [PATCH 2/3] Newsfile

---
 changelog.d/5743.bugfix | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/5743.bugfix

diff --git a/changelog.d/5743.bugfix b/changelog.d/5743.bugfix
new file mode 100644
index 000000000000..a160e9945f48
--- /dev/null
+++ b/changelog.d/5743.bugfix
@@ -0,0 +1 @@
+Log when we receive receipt from a different origin.

From 65afc535a6a3fd61ea91c99ed2284b6fd0c4e204 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 23 Jul 2019 15:14:21 +0100
Subject: [PATCH 3/3] Update changelog.d/5743.bugfix

Co-Authored-By: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
---
 changelog.d/5743.bugfix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/changelog.d/5743.bugfix b/changelog.d/5743.bugfix
index a160e9945f48..65728ff079fb 100644
--- a/changelog.d/5743.bugfix
+++ b/changelog.d/5743.bugfix
@@ -1 +1 @@
-Log when we receive receipt from a different origin.
+Log when we receive an event receipt from an unexpected origin.