Merge pull request #5440 from matrix-org/babolivier/third_party_event_rules

Allow server admins to define implementations of extra rules for allowing or denying incoming events

2 files changed, 78 insertions, 4 deletions

diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index ac5ca79143..983ac9f915 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
-# Copyright 2018 New Vector Ltd
+# Copyright 2017-2018 New Vector Ltd
+# 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.
@@ -33,6 +34,7 @@ from synapse.api.constants import EventTypes, Membership, RejectedReason
 from synapse.api.errors import (
     AuthError,
     CodeMessageException,
+    Codes,
     FederationDeniedError,
     FederationError,
     RequestSendFailed,
@@ -127,6 +129,8 @@ class FederationHandler(BaseHandler):
         self.room_queues = {}
         self._room_pdu_linearizer = Linearizer("fed_room_pdu")
 
+        self.third_party_event_rules = hs.get_third_party_event_rules()
+
     @defer.inlineCallbacks
     def on_receive_pdu(
             self, origin, pdu, sent_to_us_directly=False,
@@ -1258,6 +1262,15 @@ class FederationHandler(BaseHandler):
             logger.warn("Failed to create join %r because %s", event, e)
             raise e
 
+        event_allowed = yield self.third_party_event_rules.check_event_allowed(
+            event, context,
+        )
+        if not event_allowed:
+            logger.info("Creation of join %s forbidden by third-party rules", event)
+            raise SynapseError(
+                403, "This event is not allowed in this context", Codes.FORBIDDEN,
+            )
+
         # The remote hasn't signed it yet, obviously. We'll do the full checks
         # when we get the event back in `on_send_join_request`
         yield self.auth.check_from_context(
@@ -1300,6 +1313,15 @@ class FederationHandler(BaseHandler):
             origin, event
         )
 
+        event_allowed = yield self.third_party_event_rules.check_event_allowed(
+            event, context,
+        )
+        if not event_allowed:
+            logger.info("Sending of join %s forbidden by third-party rules", event)
+            raise SynapseError(
+                403, "This event is not allowed in this context", Codes.FORBIDDEN,
+            )
+
         logger.debug(
             "on_send_join_request: After _handle_new_event: %s, sigs: %s",
             event.event_id,
@@ -1458,6 +1480,15 @@ class FederationHandler(BaseHandler):
             builder=builder,
         )
 
+        event_allowed = yield self.third_party_event_rules.check_event_allowed(
+            event, context,
+        )
+        if not event_allowed:
+            logger.warning("Creation of leave %s forbidden by third-party rules", event)
+            raise SynapseError(
+                403, "This event is not allowed in this context", Codes.FORBIDDEN,
+            )
+
         try:
             # The remote hasn't signed it yet, obviously. We'll do the full checks
             # when we get the event back in `on_send_leave_request`
@@ -1484,10 +1515,19 @@ class FederationHandler(BaseHandler):
 
         event.internal_metadata.outlier = False
 
-        yield self._handle_new_event(
+        context = yield self._handle_new_event(
             origin, event
         )
 
+        event_allowed = yield self.third_party_event_rules.check_event_allowed(
+            event, context,
+        )
+        if not event_allowed:
+            logger.info("Sending of leave %s forbidden by third-party rules", event)
+            raise SynapseError(
+                403, "This event is not allowed in this context", Codes.FORBIDDEN,
+            )
+
         logger.debug(
             "on_send_leave_request: After _handle_new_event: %s, sigs: %s",
             event.event_id,
@@ -2550,6 +2590,18 @@ class FederationHandler(BaseHandler):
                 builder=builder
             )
 
+            event_allowed = yield self.third_party_event_rules.check_event_allowed(
+                event, context,
+            )
+            if not event_allowed:
+                logger.info(
+                    "Creation of threepid invite %s forbidden by third-party rules",
+                    event,
+                )
+                raise SynapseError(
+                    403, "This event is not allowed in this context", Codes.FORBIDDEN,
+                )
+
             event, context = yield self.add_display_name_to_third_party_invite(
                 room_version, event_dict, event, context
             )
@@ -2598,6 +2650,18 @@ class FederationHandler(BaseHandler):
             builder=builder,
         )
 
+        event_allowed = yield self.third_party_event_rules.check_event_allowed(
+            event, context,
+        )
+        if not event_allowed:
+            logger.warning(
+                "Exchange of threepid invite %s forbidden by third-party rules",
+                event,
+            )
+            raise SynapseError(
+                403, "This event is not allowed in this context", Codes.FORBIDDEN,
+            )
+
         event, context = yield self.add_display_name_to_third_party_invite(
             room_version, event_dict, event, context
         )
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 0b02469ceb..11650dc80c 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
-# Copyright 2014 - 2016 OpenMarket Ltd
-# Copyright 2017 - 2018 New Vector Ltd
+# Copyright 2014-2016 OpenMarket Ltd
+# Copyright 2017-2018 New Vector Ltd
+# 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.
@@ -248,6 +249,7 @@ class EventCreationHandler(object):
         self.action_generator = hs.get_action_generator()
 
         self.spam_checker = hs.get_spam_checker()
+        self.third_party_event_rules = hs.get_third_party_event_rules()
 
         self._block_events_without_consent_error = (
             self.config.block_events_without_consent_error
@@ -658,6 +660,14 @@ class EventCreationHandler(object):
         else:
             room_version = yield self.store.get_room_version(event.room_id)
 
+        event_allowed = yield self.third_party_event_rules.check_event_allowed(
+            event, context,
+        )
+        if not event_allowed:
+            raise SynapseError(
+                403, "This event is not allowed in this context", Codes.FORBIDDEN,
+            )
+
         try:
             yield self.auth.check_from_context(room_version, event, context)
         except AuthError as err: