Merge branch 'rav/simplify_event_auth_interface' into develop

9 files changed, 36 insertions, 73 deletions

diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index 4c0b587a76..e23503c1e0 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -45,9 +45,7 @@ if typing.TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-def validate_event_for_room_version(
-    room_version_obj: RoomVersion, event: "EventBase"
-) -> None:
+def validate_event_for_room_version(event: "EventBase") -> None:
     """Ensure that the event complies with the limits, and has the right signatures
 
     NB: does not *validate* the signatures - it assumes that any signatures present
@@ -60,12 +58,10 @@ def validate_event_for_room_version(
     NB: This is used to check events that have been received over federation. As such,
     it can only enforce the checks specified in the relevant room version, to avoid
     a split-brain situation where some servers accept such events, and others reject
-    them.
-
-    TODO: consider moving this into EventValidator
+    them. See also EventValidator, which contains extra checks which are applied only to
+    locally-generated events.
 
     Args:
-        room_version_obj: the version of the room which contains this event
         event: the event to be checked
 
     Raises:
@@ -103,7 +99,7 @@ def validate_event_for_room_version(
             raise AuthError(403, "Event not signed by sending server")
 
     is_invite_via_allow_rule = (
-        room_version_obj.msc3083_join_rules
+        event.room_version.msc3083_join_rules
         and event.type == EventTypes.Member
         and event.membership == Membership.JOIN
         and EventContentFields.AUTHORISING_USER in event.content
@@ -117,7 +113,6 @@ def validate_event_for_room_version(
 
 
 def check_auth_rules_for_event(
-    room_version_obj: RoomVersion,
     event: "EventBase",
     auth_events: Iterable["EventBase"],
 ) -> None:
@@ -136,7 +131,6 @@ def check_auth_rules_for_event(
        a bunch of other tests.
 
     Args:
-        room_version_obj: the version of the room
         event: the event being checked.
         auth_events: the room state to check the events against.
 
@@ -205,7 +199,10 @@ def check_auth_rules_for_event(
             raise AuthError(403, "This room has been marked as unfederatable.")
 
     # 4. If type is m.room.aliases
-    if event.type == EventTypes.Aliases and room_version_obj.special_case_aliases_auth:
+    if (
+        event.type == EventTypes.Aliases
+        and event.room_version.special_case_aliases_auth
+    ):
         # 4a. If event has no state_key, reject
         if not event.is_state():
             raise AuthError(403, "Alias event must be a state event")
@@ -225,7 +222,7 @@ def check_auth_rules_for_event(
 
     # 5. If type is m.room.membership
     if event.type == EventTypes.Member:
-        _is_membership_change_allowed(room_version_obj, event, auth_dict)
+        _is_membership_change_allowed(event.room_version, event, auth_dict)
         logger.debug("Allowing! %s", event)
         return
 
@@ -247,17 +244,17 @@ def check_auth_rules_for_event(
     _can_send_event(event, auth_dict)
 
     if event.type == EventTypes.PowerLevels:
-        _check_power_levels(room_version_obj, event, auth_dict)
+        _check_power_levels(event.room_version, event, auth_dict)
 
     if event.type == EventTypes.Redaction:
-        check_redaction(room_version_obj, event, auth_dict)
+        check_redaction(event.room_version, event, auth_dict)
 
     if (
         event.type == EventTypes.MSC2716_INSERTION
         or event.type == EventTypes.MSC2716_BATCH
         or event.type == EventTypes.MSC2716_MARKER
     ):
-        check_historical(room_version_obj, event, auth_dict)
+        check_historical(event.room_version, event, auth_dict)
 
     logger.debug("Allowing! %s", event)
 
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
index 29fa9b3880..27c8beba25 100644
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@@ -35,6 +35,10 @@ class EventValidator:
     def validate_new(self, event: EventBase, config: HomeServerConfig) -> None:
         """Validates the event has roughly the right format
 
+        Suitable for checking a locally-created event. It has stricter checks than
+        is appropriate for an event received over federation (for which, see
+        event_auth.validate_event_for_room_version)
+
         Args:
             event: The event to validate.
             config: The homeserver's configuration.
diff --git a/synapse/handlers/event_auth.py b/synapse/handlers/event_auth.py
index 6bed464351..ed4149bd58 100644
--- a/synapse/handlers/event_auth.py
+++ b/synapse/handlers/event_auth.py
@@ -48,14 +48,13 @@ class EventAuthHandler:
 
     async def check_auth_rules_from_context(
         self,
-        room_version_obj: RoomVersion,
         event: EventBase,
         context: EventContext,
     ) -> None:
         """Check an event passes the auth rules at its own auth events"""
         auth_event_ids = event.auth_event_ids()
         auth_events_by_id = await self._store.get_events(auth_event_ids)
-        check_auth_rules_for_event(room_version_obj, event, auth_events_by_id.values())
+        check_auth_rules_for_event(event, auth_events_by_id.values())
 
     def compute_auth_events(
         self,
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 5e16139626..1e5694244a 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -800,9 +800,7 @@ class FederationHandler:
 
         # 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`
-        await self._event_auth_handler.check_auth_rules_from_context(
-            room_version, event, context
-        )
+        await self._event_auth_handler.check_auth_rules_from_context(event, context)
         return event
 
     async def on_invite_request(
@@ -973,9 +971,7 @@ class FederationHandler:
         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`
-            await self._event_auth_handler.check_auth_rules_from_context(
-                room_version_obj, event, context
-            )
+            await self._event_auth_handler.check_auth_rules_from_context(event, context)
         except AuthError as e:
             logger.warning("Failed to create new leave %r because %s", event, e)
             raise e
@@ -1034,9 +1030,7 @@ class FederationHandler:
         try:
             # The remote hasn't signed it yet, obviously. We'll do the full checks
             # when we get the event back in `on_send_knock_request`
-            await self._event_auth_handler.check_auth_rules_from_context(
-                room_version_obj, event, context
-            )
+            await self._event_auth_handler.check_auth_rules_from_context(event, context)
         except AuthError as e:
             logger.warning("Failed to create new knock %r because %s", event, e)
             raise e
@@ -1207,9 +1201,9 @@ class FederationHandler:
             event.internal_metadata.send_on_behalf_of = self.hs.hostname
 
             try:
-                validate_event_for_room_version(room_version_obj, event)
+                validate_event_for_room_version(event)
                 await self._event_auth_handler.check_auth_rules_from_context(
-                    room_version_obj, event, context
+                    event, context
                 )
             except AuthError as e:
                 logger.warning("Denying new third party invite %r because %s", event, e)
@@ -1259,10 +1253,8 @@ class FederationHandler:
         )
 
         try:
-            validate_event_for_room_version(room_version_obj, event)
-            await self._event_auth_handler.check_auth_rules_from_context(
-                room_version_obj, event, context
-            )
+            validate_event_for_room_version(event)
+            await self._event_auth_handler.check_auth_rules_from_context(event, context)
         except AuthError as e:
             logger.warning("Denying third party invite %r because %s", event, e)
             raise e
diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py
index 9889d1cb44..6c9e6a00b5 100644
--- a/synapse/handlers/federation_event.py
+++ b/synapse/handlers/federation_event.py
@@ -1430,9 +1430,6 @@ class FederationEventHandler:
             allow_rejected=True,
         )
 
-        room_version = await self._store.get_room_version_id(room_id)
-        room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
-
         def prep(event: EventBase) -> Optional[Tuple[EventBase, EventContext]]:
             with nested_logging_context(suffix=event.event_id):
                 auth = []
@@ -1455,8 +1452,8 @@ class FederationEventHandler:
 
                 context = EventContext.for_outlier(self._storage_controllers)
                 try:
-                    validate_event_for_room_version(room_version_obj, event)
-                    check_auth_rules_for_event(room_version_obj, event, auth)
+                    validate_event_for_room_version(event)
+                    check_auth_rules_for_event(event, auth)
                 except AuthError as e:
                     logger.warning("Rejecting %r because %s", event, e)
                     context.rejected = RejectedReason.AUTH_ERROR
@@ -1499,11 +1496,8 @@ class FederationEventHandler:
         assert not event.internal_metadata.outlier
 
         # first of all, check that the event itself is valid.
-        room_version = await self._store.get_room_version_id(event.room_id)
-        room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
-
         try:
-            validate_event_for_room_version(room_version_obj, event)
+            validate_event_for_room_version(event)
         except AuthError as e:
             logger.warning("While validating received event %r: %s", event, e)
             # TODO: use a different rejected reason here?
@@ -1521,7 +1515,7 @@ class FederationEventHandler:
 
         # ... and check that the event passes auth at those auth events.
         try:
-            check_auth_rules_for_event(room_version_obj, event, claimed_auth_events)
+            check_auth_rules_for_event(event, claimed_auth_events)
         except AuthError as e:
             logger.warning(
                 "While checking auth of %r against auth_events: %s", event, e
@@ -1569,9 +1563,7 @@ class FederationEventHandler:
             auth_events_for_auth = calculated_auth_event_map
 
         try:
-            check_auth_rules_for_event(
-                room_version_obj, event, auth_events_for_auth.values()
-            )
+            check_auth_rules_for_event(event, auth_events_for_auth.values())
         except AuthError as e:
             logger.warning("Failed auth resolution for %r because %s", event, e)
             context.rejected = RejectedReason.AUTH_ERROR
@@ -1671,7 +1663,7 @@ class FederationEventHandler:
         )
 
         try:
-            check_auth_rules_for_event(room_version_obj, event, current_auth_events)
+            check_auth_rules_for_event(event, current_auth_events)
         except AuthError as e:
             logger.warning(
                 "Soft-failing %r (from %s) because %s",
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 294217cc23..9b17939163 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -42,7 +42,7 @@ from synapse.api.errors import (
     SynapseError,
     UnsupportedRoomVersionError,
 )
-from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersions
+from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.api.urls import ConsentURIBuilder
 from synapse.event_auth import validate_event_for_room_version
 from synapse.events import EventBase, relation_from_event
@@ -1274,23 +1274,6 @@ class EventCreationHandler:
                 )
                 return prev_event
 
-        if event.is_state() and (event.type, event.state_key) == (
-            EventTypes.Create,
-            "",
-        ):
-            room_version_id = event.content.get(
-                "room_version", RoomVersions.V1.identifier
-            )
-            maybe_room_version_obj = KNOWN_ROOM_VERSIONS.get(room_version_id)
-            if not maybe_room_version_obj:
-                raise UnsupportedRoomVersionError(
-                    "Attempt to create a room with unsupported room version %s"
-                    % (room_version_id,)
-                )
-            room_version_obj = maybe_room_version_obj
-        else:
-            room_version_obj = await self.store.get_room_version(event.room_id)
-
         if event.internal_metadata.is_out_of_band_membership():
             # the only sort of out-of-band-membership events we expect to see here are
             # invite rejections and rescinded knocks that we have generated ourselves.
@@ -1298,9 +1281,9 @@ class EventCreationHandler:
             assert event.content["membership"] == Membership.LEAVE
         else:
             try:
-                validate_event_for_room_version(room_version_obj, event)
+                validate_event_for_room_version(event)
                 await self._event_auth_handler.check_auth_rules_from_context(
-                    room_version_obj, event, context
+                    event, context
                 )
             except AuthError as err:
                 logger.warning("Denying new event %r because %s", event, err)
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 520663f172..d8918ee1aa 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -226,10 +226,9 @@ class RoomCreationHandler:
                 },
             },
         )
-        old_room_version = await self.store.get_room_version(old_room_id)
-        validate_event_for_room_version(old_room_version, tombstone_event)
+        validate_event_for_room_version(tombstone_event)
         await self._event_auth_handler.check_auth_rules_from_context(
-            old_room_version, tombstone_event, tombstone_context
+            tombstone_event, tombstone_context
         )
 
         # Upgrade the room
diff --git a/synapse/state/v1.py b/synapse/state/v1.py
index 499a328201..8bbb4ce41c 100644
--- a/synapse/state/v1.py
+++ b/synapse/state/v1.py
@@ -30,7 +30,7 @@ from typing import (
 from synapse import event_auth
 from synapse.api.constants import EventTypes
 from synapse.api.errors import AuthError
-from synapse.api.room_versions import RoomVersion, RoomVersions
+from synapse.api.room_versions import RoomVersion
 from synapse.events import EventBase
 from synapse.types import MutableStateMap, StateMap
 
@@ -331,7 +331,6 @@ def _resolve_auth_events(
         try:
             # The signatures have already been checked at this point
             event_auth.check_auth_rules_for_event(
-                RoomVersions.V1,
                 event,
                 auth_events.values(),
             )
@@ -349,7 +348,6 @@ def _resolve_normal_events(
         try:
             # The signatures have already been checked at this point
             event_auth.check_auth_rules_for_event(
-                RoomVersions.V1,
                 event,
                 auth_events.values(),
             )
diff --git a/synapse/state/v2.py b/synapse/state/v2.py
index 0e609114ef..6a16f38a15 100644
--- a/synapse/state/v2.py
+++ b/synapse/state/v2.py
@@ -574,7 +574,6 @@ async def _iterative_auth_checks(
 
         try:
             event_auth.check_auth_rules_for_event(
-                room_version,
                 event,
                 auth_events.values(),
             )