Merge tag 'v0.33.1'

Synapse 0.33.1 (2018-08-02)
===========================

SECURITY FIXES
--------------

- Fix a potential issue where servers could request events for rooms they have not joined. (`#3641 <https://github.com/matrix-org/synapse/issues/3641>`_)
- Fix a potential issue where users could see events in private rooms before they joined. (`#3642 <https://github.com/matrix-org/synapse/issues/3642>`_)

8 files changed, 63 insertions, 19 deletions

diff --git a/synapse/__init__.py b/synapse/__init__.py
index 5c0f2f83aa..1810cb6fcd 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -17,4 +17,4 @@
 """ This is a reference implementation of a Matrix home server.
 """
 
-__version__ = "0.33.0"
+__version__ = "0.33.1"
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 48f26db67c..10e71c78ce 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -425,6 +425,7 @@ class FederationServer(FederationBase):
             ret = yield self.handler.on_query_auth(
                 origin,
                 event_id,
+                room_id,
                 signed_auth,
                 content.get("rejects", []),
                 content.get("missing", []),
diff --git a/synapse/handlers/events.py b/synapse/handlers/events.py
index c3f2d7feff..f772e62c28 100644
--- a/synapse/handlers/events.py
+++ b/synapse/handlers/events.py
@@ -19,10 +19,12 @@ import random
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
+from synapse.api.errors import AuthError
 from synapse.events import EventBase
 from synapse.events.utils import serialize_event
 from synapse.types import UserID
 from synapse.util.logutils import log_function
+from synapse.visibility import filter_events_for_client
 
 from ._base import BaseHandler
 
@@ -129,11 +131,13 @@ class EventStreamHandler(BaseHandler):
 class EventHandler(BaseHandler):
 
     @defer.inlineCallbacks
-    def get_event(self, user, event_id):
+    def get_event(self, user, room_id, event_id):
         """Retrieve a single specified event.
 
         Args:
             user (synapse.types.UserID): The user requesting the event
+            room_id (str|None): The expected room id. We'll return None if the
+                event's room does not match.
             event_id (str): The event ID to obtain.
         Returns:
             dict: An event, or None if there is no event matching this ID.
@@ -142,13 +146,26 @@ class EventHandler(BaseHandler):
             AuthError if the user does not have the rights to inspect this
             event.
         """
-        event = yield self.store.get_event(event_id)
+        event = yield self.store.get_event(event_id, check_room_id=room_id)
 
         if not event:
             defer.returnValue(None)
             return
 
-        if hasattr(event, "room_id"):
-            yield self.auth.check_joined_room(event.room_id, user.to_string())
+        users = yield self.store.get_users_in_room(event.room_id)
+        is_peeking = user.to_string() not in users
+
+        filtered = yield filter_events_for_client(
+            self.store,
+            user.to_string(),
+            [event],
+            is_peeking=is_peeking
+        )
+
+        if not filtered:
+            raise AuthError(
+                403,
+                "You don't have permission to access that event."
+            )
 
         defer.returnValue(event)
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 20fb46fc89..60391d07c4 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -1349,6 +1349,11 @@ class FederationHandler(BaseHandler):
     def get_state_for_pdu(self, room_id, event_id):
         """Returns the state at the event. i.e. not including said event.
         """
+
+        event = yield self.store.get_event(
+            event_id, allow_none=False, check_room_id=room_id,
+        )
+
         state_groups = yield self.store.get_state_groups(
             room_id, [event_id]
         )
@@ -1359,8 +1364,7 @@ class FederationHandler(BaseHandler):
                 (e.type, e.state_key): e for e in state
             }
 
-            event = yield self.store.get_event(event_id)
-            if event and event.is_state():
+            if event.is_state():
                 # Get previous state
                 if "replaces_state" in event.unsigned:
                     prev_id = event.unsigned["replaces_state"]
@@ -1391,6 +1395,10 @@ class FederationHandler(BaseHandler):
     def get_state_ids_for_pdu(self, room_id, event_id):
         """Returns the state at the event. i.e. not including said event.
         """
+        event = yield self.store.get_event(
+            event_id, allow_none=False, check_room_id=room_id,
+        )
+
         state_groups = yield self.store.get_state_groups_ids(
             room_id, [event_id]
         )
@@ -1399,8 +1407,7 @@ class FederationHandler(BaseHandler):
             _, state = state_groups.items().pop()
             results = state
 
-            event = yield self.store.get_event(event_id)
-            if event and event.is_state():
+            if event.is_state():
                 # Get previous state
                 if "replaces_state" in event.unsigned:
                     prev_id = event.unsigned["replaces_state"]
@@ -1706,8 +1713,19 @@ class FederationHandler(BaseHandler):
         defer.returnValue(context)
 
     @defer.inlineCallbacks
-    def on_query_auth(self, origin, event_id, remote_auth_chain, rejects,
+    def on_query_auth(self, origin, event_id, room_id, remote_auth_chain, rejects,
                       missing):
+        in_room = yield self.auth.check_host_in_room(
+            room_id,
+            origin
+        )
+        if not in_room:
+            raise AuthError(403, "Host not in room.")
+
+        event = yield self.store.get_event(
+            event_id, allow_none=False, check_room_id=room_id
+        )
+
         # Just go through and process each event in `remote_auth_chain`. We
         # don't want to fall into the trap of `missing` being wrong.
         for e in remote_auth_chain:
@@ -1717,7 +1735,6 @@ class FederationHandler(BaseHandler):
                 pass
 
         # Now get the current auth_chain for the event.
-        event = yield self.store.get_event(event_id)
         local_auth_chain = yield self.store.get_auth_chain(
             [auth_id for auth_id, _ in event.auth_events],
             include_given=True
diff --git a/synapse/rest/client/v1/events.py b/synapse/rest/client/v1/events.py
index b70c9c2806..0f3a2e8b51 100644
--- a/synapse/rest/client/v1/events.py
+++ b/synapse/rest/client/v1/events.py
@@ -88,7 +88,7 @@ class EventRestServlet(ClientV1RestServlet):
     @defer.inlineCallbacks
     def on_GET(self, request, event_id):
         requester = yield self.auth.get_user_by_req(request)
-        event = yield self.event_handler.get_event(requester.user, event_id)
+        event = yield self.event_handler.get_event(requester.user, None, event_id)
 
         time_now = self.clock.time_msec()
         if event:
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 3d62447854..2a679ac830 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -508,7 +508,7 @@ class RoomEventServlet(ClientV1RestServlet):
     @defer.inlineCallbacks
     def on_GET(self, request, room_id, event_id):
         requester = yield self.auth.get_user_by_req(request)
-        event = yield self.event_handler.get_event(requester.user, event_id)
+        event = yield self.event_handler.get_event(requester.user, room_id, event_id)
 
         time_now = self.clock.time_msec()
         if event:
diff --git a/synapse/storage/event_federation.py b/synapse/storage/event_federation.py
index 8d366d1b91..7cd77c1c29 100644
--- a/synapse/storage/event_federation.py
+++ b/synapse/storage/event_federation.py
@@ -343,6 +343,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore,
                 table="events",
                 keyvalues={
                     "event_id": event_id,
+                    "room_id": room_id,
                 },
                 retcol="depth",
                 allow_none=True,
diff --git a/synapse/storage/events_worker.py b/synapse/storage/events_worker.py
index 67433606c6..6b8a8e908f 100644
--- a/synapse/storage/events_worker.py
+++ b/synapse/storage/events_worker.py
@@ -19,7 +19,7 @@ from canonicaljson import json
 
 from twisted.internet import defer
 
-from synapse.api.errors import SynapseError
+from synapse.api.errors import NotFoundError
 # these are only included to make the type annotations work
 from synapse.events import EventBase  # noqa: F401
 from synapse.events import FrozenEvent
@@ -76,7 +76,7 @@ class EventsWorkerStore(SQLBaseStore):
     @defer.inlineCallbacks
     def get_event(self, event_id, check_redacted=True,
                   get_prev_content=False, allow_rejected=False,
-                  allow_none=False):
+                  allow_none=False, check_room_id=None):
         """Get an event from the database by event_id.
 
         Args:
@@ -87,7 +87,9 @@ class EventsWorkerStore(SQLBaseStore):
                 include the previous states content in the unsigned field.
             allow_rejected (bool): If True return rejected events.
             allow_none (bool): If True, return None if no event found, if
-                False throw an exception.
+                False throw a NotFoundError
+            check_room_id (str|None): if not None, check the room of the found event.
+                If there is a mismatch, behave as per allow_none.
 
         Returns:
             Deferred : A FrozenEvent.
@@ -99,10 +101,16 @@ class EventsWorkerStore(SQLBaseStore):
             allow_rejected=allow_rejected,
         )
 
-        if not events and not allow_none:
-            raise SynapseError(404, "Could not find event %s" % (event_id,))
+        event = events[0] if events else None
 
-        defer.returnValue(events[0] if events else None)
+        if event is not None and check_room_id is not None:
+            if event.room_id != check_room_id:
+                event = None
+
+        if event is None and not allow_none:
+            raise NotFoundError("Could not find event %s" % (event_id,))
+
+        defer.returnValue(event)
 
     @defer.inlineCallbacks
     def get_events(self, event_ids, check_redacted=True,