5 files changed, 112 insertions, 6 deletions
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 5321864d51..9bfd25c86e 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -19,7 +19,9 @@ from twisted.internet import defer
 
 from synapse.api.constants import Membership, JoinRules
 from synapse.api.errors import AuthError, StoreError, Codes, SynapseError
-from synapse.api.events.room import RoomMemberEvent, RoomPowerLevelsEvent
+from synapse.api.events.room import (
+    RoomMemberEvent, RoomPowerLevelsEvent, RoomRedactionEvent,
+)
 from synapse.util.logutils import log_function
 
 import logging
@@ -70,6 +72,9 @@ class Auth(object):
                 if event.type == RoomPowerLevelsEvent.TYPE:
                     yield self._check_power_levels(event)
 
+                if event.type == RoomRedactionEvent.TYPE:
+                    yield self._check_redaction(event)
+
                 defer.returnValue(True)
             else:
                 raise AuthError(500, "Unknown event: %s" % event)
@@ -170,7 +175,7 @@ class Auth(object):
                     event.room_id,
                     event.user_id,
                 )
-                _, kick_level = yield self.store.get_ops_levels(event.room_id)
+                _, kick_level, _ = yield self.store.get_ops_levels(event.room_id)
 
                 if kick_level:
                     kick_level = int(kick_level)
@@ -187,7 +192,7 @@ class Auth(object):
                 event.user_id,
             )
 
-            ban_level, _ = yield self.store.get_ops_levels(event.room_id)
+            ban_level, _, _  = yield self.store.get_ops_levels(event.room_id)
 
             if ban_level:
                 ban_level = int(ban_level)
@@ -322,6 +327,29 @@ class Auth(object):
                 )
 
     @defer.inlineCallbacks
+    def _check_redaction(self, event):
+        user_level = yield self.store.get_power_level(
+            event.room_id,
+            event.user_id,
+        )
+
+        if user_level:
+            user_level = int(user_level)
+        else:
+            user_level = 0
+
+        _, _, redact_level  = yield self.store.get_ops_levels(event.room_id)
+
+        if not redact_level:
+            redact_level = 50
+
+        if user_level < redact_level:
+            raise AuthError(
+                403,
+                "You don't have permission to redact events"
+            )
+
+    @defer.inlineCallbacks
     def _check_power_levels(self, event):
         for k, v in event.content.items():
             if k == "default":
diff --git a/synapse/api/events/__init__.py b/synapse/api/events/__init__.py
index 0cee196851..f66fea2904 100644
--- a/synapse/api/events/__init__.py
+++ b/synapse/api/events/__init__.py
@@ -22,7 +22,8 @@ def serialize_event(hs, e):
     if not isinstance(e, SynapseEvent):
         return e
 
-    d = e.get_dict()
+    # Should this strip out None's?
+    d = {k: v for k, v in e.get_dict().items()}
     if "age_ts" in d:
         d["age"] = int(hs.get_clock().time_msec()) - d["age_ts"]
         del d["age_ts"]
@@ -58,17 +59,19 @@ class SynapseEvent(JsonEncodedObject):
         "required_power_level",
         "age_ts",
         "prev_content",
+        "prev_state",
+        "redacted_because",
     ]
 
     internal_keys = [
         "is_state",
         "prev_events",
-        "prev_state",
         "depth",
         "destinations",
         "origin",
         "outlier",
         "power_level",
+        "redacted",
     ]
 
     required_keys = [
diff --git a/synapse/api/events/factory.py b/synapse/api/events/factory.py
index d3d96d73eb..0d94850cec 100644
--- a/synapse/api/events/factory.py
+++ b/synapse/api/events/factory.py
@@ -17,7 +17,8 @@ from synapse.api.events.room import (
     RoomTopicEvent, MessageEvent, RoomMemberEvent, FeedbackEvent,
     InviteJoinEvent, RoomConfigEvent, RoomNameEvent, GenericEvent,
     RoomPowerLevelsEvent, RoomJoinRulesEvent, RoomOpsPowerLevelsEvent,
-    RoomCreateEvent, RoomAddStateLevelEvent, RoomSendEventLevelEvent
+    RoomCreateEvent, RoomAddStateLevelEvent, RoomSendEventLevelEvent,
+    RoomRedactionEvent,
 )
 
 from synapse.util.stringutils import random_string
@@ -39,6 +40,7 @@ class EventFactory(object):
         RoomAddStateLevelEvent,
         RoomSendEventLevelEvent,
         RoomOpsPowerLevelsEvent,
+        RoomRedactionEvent,
     ]
 
     def __init__(self, hs):
diff --git a/synapse/api/events/room.py b/synapse/api/events/room.py
index 3a4dbc58ce..cd936074fc 100644
--- a/synapse/api/events/room.py
+++ b/synapse/api/events/room.py
@@ -180,3 +180,12 @@ class RoomAliasesEvent(SynapseStateEvent):
 
     def get_content_template(self):
         return {}
+
+
+class RoomRedactionEvent(SynapseEvent):
+    TYPE = "m.room.redaction"
+
+    valid_keys = SynapseEvent.valid_keys + ["redacts"]
+
+    def get_content_template(self):
+        return {}
diff --git a/synapse/api/events/utils.py b/synapse/api/events/utils.py
new file mode 100644
index 0000000000..c3a32be8c1
--- /dev/null
+++ b/synapse/api/events/utils.py
@@ -0,0 +1,64 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .room import (
+    RoomMemberEvent, RoomJoinRulesEvent, RoomPowerLevelsEvent,
+    RoomAddStateLevelEvent, RoomSendEventLevelEvent, RoomOpsPowerLevelsEvent,
+    RoomAliasesEvent, RoomCreateEvent,
+)
+
+def prune_event(event):
+    """ Prunes the given event of all keys we don't know about or think could
+    potentially be dodgy.
+
+    This is used when we "redact" an event. We want to remove all fields that
+    the user has specified, but we do want to keep necessary information like
+    type, state_key etc.
+    """
+
+    # Remove all extraneous fields.
+    event.unrecognized_keys = {}
+
+    new_content = {}
+
+    def add_fields(*fields):
+        for field in fields:
+            if field in event.content:
+                new_content[field] = event.content[field]
+
+    if event.type == RoomMemberEvent.TYPE:
+        add_fields("membership")
+    elif event.type == RoomCreateEvent.TYPE:
+        add_fields("creator")
+    elif event.type == RoomJoinRulesEvent.TYPE:
+        add_fields("join_rule")
+    elif event.type == RoomPowerLevelsEvent.TYPE:
+        # TODO: Actually check these are valid user_ids etc.
+        add_fields("default")
+        for k, v in event.content.items():
+            if k.startswith("@") and isinstance(v, (int, long)):
+                new_content[k] = v
+    elif event.type == RoomAddStateLevelEvent.TYPE:
+        add_fields("level")
+    elif event.type == RoomSendEventLevelEvent.TYPE:
+        add_fields("level")
+    elif event.type == RoomOpsPowerLevelsEvent.TYPE:
+        add_fields("kick_level", "ban_level", "redact_level")
+    elif event.type == RoomAliasesEvent.TYPE:
+        add_fields("aliases")
+
+    event.content = new_content
+
+    return event