Move some event auth checks out to a different method (#13065)

* Add auth events to events used in tests

* Move some event auth checks out to a different method

Some of the event auth checks apply to an event's auth_events, rather than the
state at the event - which means they can play no part in state
resolution. Move them out to a separate method.

* Rename check_auth_rules_for_event

Now it only checks the state-dependent auth rules, it needs a better name.

1 files changed, 113 insertions, 54 deletions

diff --git a/tests/test_event_auth.py b/tests/test_event_auth.py
index 229ecd84a6..e8e458cfd3 100644
--- a/tests/test_event_auth.py
+++ b/tests/test_event_auth.py
@@ -1,4 +1,4 @@
-# Copyright 2018 New Vector Ltd
+# Copyright 2018-2022 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.
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import unittest
-from typing import Optional
+from typing import Collection, Dict, Iterable, List, Optional
 
 from parameterized import parameterized
 
@@ -22,8 +22,41 @@ from synapse.api.constants import EventContentFields
 from synapse.api.errors import AuthError
 from synapse.api.room_versions import EventFormatVersions, RoomVersion, RoomVersions
 from synapse.events import EventBase, make_event_from_dict
+from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.types import JsonDict, get_domain_from_id
 
+from tests.test_utils import get_awaitable_result
+
+
+class _StubEventSourceStore:
+    """A stub implementation of the EventSourceStore"""
+
+    def __init__(self):
+        self._store: Dict[str, EventBase] = {}
+
+    def add_event(self, event: EventBase):
+        self._store[event.event_id] = event
+
+    def add_events(self, events: Iterable[EventBase]):
+        for event in events:
+            self._store[event.event_id] = event
+
+    async def get_events(
+        self,
+        event_ids: Collection[str],
+        redact_behaviour: EventRedactBehaviour,
+        get_prev_content: bool = False,
+        allow_rejected: bool = False,
+    ) -> Dict[str, EventBase]:
+        assert allow_rejected
+        assert not get_prev_content
+        assert redact_behaviour == EventRedactBehaviour.as_is
+        results = {}
+        for e in event_ids:
+            if e in self._store:
+                results[e] = self._store[e]
+        return results
+
 
 class EventAuthTestCase(unittest.TestCase):
     def test_rejected_auth_events(self):
@@ -36,11 +69,15 @@ class EventAuthTestCase(unittest.TestCase):
             _join_event(RoomVersions.V9, creator),
         ]
 
+        event_store = _StubEventSourceStore()
+        event_store.add_events(auth_events)
+
         # creator should be able to send state
-        event_auth.check_auth_rules_for_event(
-            _random_state_event(RoomVersions.V9, creator),
-            auth_events,
+        event = _random_state_event(RoomVersions.V9, creator, auth_events)
+        get_awaitable_result(
+            event_auth.check_state_independent_auth_rules(event_store, event)
         )
+        event_auth.check_state_dependent_auth_rules(event, auth_events)
 
         # ... but a rejected join_rules event should cause it to be rejected
         rejected_join_rules = _join_rules_event(
@@ -50,23 +87,27 @@ class EventAuthTestCase(unittest.TestCase):
         )
         rejected_join_rules.rejected_reason = "stinky"
         auth_events.append(rejected_join_rules)
+        event_store.add_event(rejected_join_rules)
 
-        self.assertRaises(
-            AuthError,
-            event_auth.check_auth_rules_for_event,
-            _random_state_event(RoomVersions.V9, creator),
-            auth_events,
-        )
+        with self.assertRaises(AuthError):
+            get_awaitable_result(
+                event_auth.check_state_independent_auth_rules(
+                    event_store,
+                    _random_state_event(RoomVersions.V9, creator),
+                )
+            )
 
         # ... even if there is *also* a good join rules
         auth_events.append(_join_rules_event(RoomVersions.V9, creator, "public"))
+        event_store.add_event(rejected_join_rules)
 
-        self.assertRaises(
-            AuthError,
-            event_auth.check_auth_rules_for_event,
-            _random_state_event(RoomVersions.V9, creator),
-            auth_events,
-        )
+        with self.assertRaises(AuthError):
+            get_awaitable_result(
+                event_auth.check_state_independent_auth_rules(
+                    event_store,
+                    _random_state_event(RoomVersions.V9, creator),
+                )
+            )
 
     def test_random_users_cannot_send_state_before_first_pl(self):
         """
@@ -82,7 +123,7 @@ class EventAuthTestCase(unittest.TestCase):
         ]
 
         # creator should be able to send state
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _random_state_event(RoomVersions.V1, creator),
             auth_events,
         )
@@ -90,7 +131,7 @@ class EventAuthTestCase(unittest.TestCase):
         # joiner should not be able to send state
         self.assertRaises(
             AuthError,
-            event_auth.check_auth_rules_for_event,
+            event_auth.check_state_dependent_auth_rules,
             _random_state_event(RoomVersions.V1, joiner),
             auth_events,
         )
@@ -119,13 +160,13 @@ class EventAuthTestCase(unittest.TestCase):
         # pleb should not be able to send state
         self.assertRaises(
             AuthError,
-            event_auth.check_auth_rules_for_event,
+            event_auth.check_state_dependent_auth_rules,
             _random_state_event(RoomVersions.V1, pleb),
             auth_events,
         ),
 
         # king should be able to send state
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _random_state_event(RoomVersions.V1, king),
             auth_events,
         )
@@ -140,27 +181,27 @@ class EventAuthTestCase(unittest.TestCase):
         ]
 
         # creator should be able to send aliases
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _alias_event(RoomVersions.V1, creator),
             auth_events,
         )
 
         # Reject an event with no state key.
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _alias_event(RoomVersions.V1, creator, state_key=""),
                 auth_events,
             )
 
         # If the domain of the sender does not match the state key, reject.
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _alias_event(RoomVersions.V1, creator, state_key="test.com"),
                 auth_events,
             )
 
         # Note that the member does *not* need to be in the room.
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _alias_event(RoomVersions.V1, other),
             auth_events,
         )
@@ -175,24 +216,24 @@ class EventAuthTestCase(unittest.TestCase):
         ]
 
         # creator should be able to send aliases
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _alias_event(RoomVersions.V6, creator),
             auth_events,
         )
 
         # No particular checks are done on the state key.
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _alias_event(RoomVersions.V6, creator, state_key=""),
             auth_events,
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _alias_event(RoomVersions.V6, creator, state_key="test.com"),
             auth_events,
         )
 
         # Per standard auth rules, the member must be in the room.
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _alias_event(RoomVersions.V6, other),
                 auth_events,
             )
@@ -220,12 +261,12 @@ class EventAuthTestCase(unittest.TestCase):
 
         # on room V1, pleb should be able to modify the notifications power level.
         if allow_modification:
-            event_auth.check_auth_rules_for_event(pl_event, auth_events)
+            event_auth.check_state_dependent_auth_rules(pl_event, auth_events)
 
         else:
             # But an MSC2209 room rejects this change.
             with self.assertRaises(AuthError):
-                event_auth.check_auth_rules_for_event(pl_event, auth_events)
+                event_auth.check_state_dependent_auth_rules(pl_event, auth_events)
 
     def test_join_rules_public(self):
         """
@@ -243,14 +284,14 @@ class EventAuthTestCase(unittest.TestCase):
         }
 
         # Check join.
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _join_event(RoomVersions.V6, pleb),
             auth_events.values(),
         )
 
         # A user cannot be force-joined to a room.
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _member_event(RoomVersions.V6, pleb, "join", sender=creator),
                 auth_events.values(),
             )
@@ -260,7 +301,7 @@ class EventAuthTestCase(unittest.TestCase):
             RoomVersions.V6, pleb, "ban"
         )
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _join_event(RoomVersions.V6, pleb),
                 auth_events.values(),
             )
@@ -269,7 +310,7 @@ class EventAuthTestCase(unittest.TestCase):
         auth_events[("m.room.member", pleb)] = _member_event(
             RoomVersions.V6, pleb, "leave"
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _join_event(RoomVersions.V6, pleb),
             auth_events.values(),
         )
@@ -278,7 +319,7 @@ class EventAuthTestCase(unittest.TestCase):
         auth_events[("m.room.member", pleb)] = _member_event(
             RoomVersions.V6, pleb, "join"
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _join_event(RoomVersions.V6, pleb),
             auth_events.values(),
         )
@@ -287,7 +328,7 @@ class EventAuthTestCase(unittest.TestCase):
         auth_events[("m.room.member", pleb)] = _member_event(
             RoomVersions.V6, pleb, "invite", sender=creator
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _join_event(RoomVersions.V6, pleb),
             auth_events.values(),
         )
@@ -309,14 +350,14 @@ class EventAuthTestCase(unittest.TestCase):
 
         # A join without an invite is rejected.
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _join_event(RoomVersions.V6, pleb),
                 auth_events.values(),
             )
 
         # A user cannot be force-joined to a room.
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _member_event(RoomVersions.V6, pleb, "join", sender=creator),
                 auth_events.values(),
             )
@@ -326,7 +367,7 @@ class EventAuthTestCase(unittest.TestCase):
             RoomVersions.V6, pleb, "ban"
         )
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _join_event(RoomVersions.V6, pleb),
                 auth_events.values(),
             )
@@ -336,7 +377,7 @@ class EventAuthTestCase(unittest.TestCase):
             RoomVersions.V6, pleb, "leave"
         )
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _join_event(RoomVersions.V6, pleb),
                 auth_events.values(),
             )
@@ -345,7 +386,7 @@ class EventAuthTestCase(unittest.TestCase):
         auth_events[("m.room.member", pleb)] = _member_event(
             RoomVersions.V6, pleb, "join"
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _join_event(RoomVersions.V6, pleb),
             auth_events.values(),
         )
@@ -354,7 +395,7 @@ class EventAuthTestCase(unittest.TestCase):
         auth_events[("m.room.member", pleb)] = _member_event(
             RoomVersions.V6, pleb, "invite", sender=creator
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _join_event(RoomVersions.V6, pleb),
             auth_events.values(),
         )
@@ -376,7 +417,7 @@ class EventAuthTestCase(unittest.TestCase):
         }
 
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _join_event(RoomVersions.V6, pleb),
                 auth_events.values(),
             )
@@ -413,7 +454,7 @@ class EventAuthTestCase(unittest.TestCase):
                 EventContentFields.AUTHORISING_USER: "@creator:example.com"
             },
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             authorised_join_event,
             auth_events.values(),
         )
@@ -429,7 +470,7 @@ class EventAuthTestCase(unittest.TestCase):
         pl_auth_events[("m.room.member", "@inviter:foo.test")] = _join_event(
             RoomVersions.V8, "@inviter:foo.test"
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _join_event(
                 RoomVersions.V8,
                 pleb,
@@ -442,7 +483,7 @@ class EventAuthTestCase(unittest.TestCase):
 
         # A join which is missing an authorised server is rejected.
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _join_event(RoomVersions.V8, pleb),
                 auth_events.values(),
             )
@@ -455,7 +496,7 @@ class EventAuthTestCase(unittest.TestCase):
             {"invite": 100, "users": {"@other:example.com": 150}},
         )
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _join_event(
                     RoomVersions.V8,
                     pleb,
@@ -469,7 +510,7 @@ class EventAuthTestCase(unittest.TestCase):
         # A user cannot be force-joined to a room. (This uses an event which
         # *would* be valid, but is sent be a different user.)
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 _member_event(
                     RoomVersions.V8,
                     pleb,
@@ -487,7 +528,7 @@ class EventAuthTestCase(unittest.TestCase):
             RoomVersions.V8, pleb, "ban"
         )
         with self.assertRaises(AuthError):
-            event_auth.check_auth_rules_for_event(
+            event_auth.check_state_dependent_auth_rules(
                 authorised_join_event,
                 auth_events.values(),
             )
@@ -496,7 +537,7 @@ class EventAuthTestCase(unittest.TestCase):
         auth_events[("m.room.member", pleb)] = _member_event(
             RoomVersions.V8, pleb, "leave"
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             authorised_join_event,
             auth_events.values(),
         )
@@ -506,7 +547,7 @@ class EventAuthTestCase(unittest.TestCase):
         auth_events[("m.room.member", pleb)] = _member_event(
             RoomVersions.V8, pleb, "join"
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _join_event(RoomVersions.V8, pleb),
             auth_events.values(),
         )
@@ -516,7 +557,7 @@ class EventAuthTestCase(unittest.TestCase):
         auth_events[("m.room.member", pleb)] = _member_event(
             RoomVersions.V8, pleb, "invite", sender=creator
         )
-        event_auth.check_auth_rules_for_event(
+        event_auth.check_state_dependent_auth_rules(
             _join_event(RoomVersions.V8, pleb),
             auth_events.values(),
         )
@@ -539,6 +580,7 @@ def _create_event(
             "state_key": "",
             "sender": user_id,
             "content": {"creator": user_id},
+            "auth_events": [],
         },
         room_version=room_version,
     )
@@ -559,6 +601,7 @@ def _member_event(
             "sender": sender or user_id,
             "state_key": user_id,
             "content": {"membership": membership, **(additional_content or {})},
+            "auth_events": [],
             "prev_events": [],
         },
         room_version=room_version,
@@ -609,7 +652,22 @@ def _alias_event(room_version: RoomVersion, sender: str, **kwargs) -> EventBase:
     return make_event_from_dict(data, room_version=room_version)
 
 
-def _random_state_event(room_version: RoomVersion, sender: str) -> EventBase:
+def _build_auth_dict_for_room_version(
+    room_version: RoomVersion, auth_events: Iterable[EventBase]
+) -> List:
+    if room_version.event_format == EventFormatVersions.V1:
+        return [(e.event_id, "not_used") for e in auth_events]
+    else:
+        return [e.event_id for e in auth_events]
+
+
+def _random_state_event(
+    room_version: RoomVersion,
+    sender: str,
+    auth_events: Optional[Iterable[EventBase]] = None,
+) -> EventBase:
+    if auth_events is None:
+        auth_events = []
     return make_event_from_dict(
         {
             "room_id": TEST_ROOM_ID,
@@ -618,6 +676,7 @@ def _random_state_event(room_version: RoomVersion, sender: str) -> EventBase:
             "sender": sender,
             "state_key": "",
             "content": {"membership": "join"},
+            "auth_events": _build_auth_dict_for_room_version(room_version, auth_events),
         },
         room_version=room_version,
     )