diff --git a/synapse/events/spamcheck.py b/synapse/events/spamcheck.py
new file mode 100644
index 0000000000..3eb4eab26a
--- /dev/null
+++ b/synapse/events/spamcheck.py
@@ -0,0 +1,38 @@
+# -*- coding: utf-8 -*-
+# Copyright 2017 New Vector 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.
+
+
+def check_event_for_spam(event):
+ """Checks if a given event is considered "spammy" by this server.
+
+ If the server considers an event spammy, then it will be rejected if
+ sent by a local user. If it is sent by a user on another server, then
+ users
+
+ Args:
+ event (synapse.events.EventBase): the event to be checked
+
+ Returns:
+ bool: True if the event is spammy.
+ """
+ if not hasattr(event, "content") or "body" not in event.content:
+ return False
+
+ # for example:
+ #
+ # if "the third flower is green" in event.content["body"]:
+ # return True
+
+ return False
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index 2339cc9034..28eaab2cef 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -12,21 +12,15 @@
# 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 twisted.internet import defer
-
-from synapse.events.utils import prune_event
-
-from synapse.crypto.event_signing import check_event_content_hash
+import logging
from synapse.api.errors import SynapseError
-
+from synapse.crypto.event_signing import check_event_content_hash
+from synapse.events import spamcheck
+from synapse.events.utils import prune_event
from synapse.util import unwrapFirstError
-from synapse.util.logcontext import preserve_fn, preserve_context_over_deferred
-
-import logging
-
+from synapse.util.logcontext import preserve_context_over_deferred, preserve_fn
+from twisted.internet import defer
logger = logging.getLogger(__name__)
@@ -117,12 +111,18 @@ class FederationBase(object):
return self._check_sigs_and_hashes([pdu])[0]
def _check_sigs_and_hashes(self, pdus):
- """Throws a SynapseError if a PDU does not have the correct
- signatures.
+ """Checks that each of the received events is correctly signed by the
+ sending server.
+
+ Args:
+ pdus (list[FrozenEvent]): the events to be checked
Returns:
- FrozenEvent: Either the given event or it redacted if it failed the
- content hash check.
+ list[Deferred]: for each input event, a deferred which:
+ * returns the original event if the checks pass
+ * returns a redacted version of the event (if the signature
+ matched but the hash did not)
+ * throws a SynapseError if the signature check failed.
"""
redacted_pdus = [
@@ -142,6 +142,14 @@ class FederationBase(object):
pdu.event_id, pdu.get_pdu_json()
)
return redacted
+
+ if spamcheck.check_event_for_spam(pdu):
+ logger.warn(
+ "Event contains spam, redacting %s: %s",
+ pdu.event_id, pdu.get_pdu_json()
+ )
+ return redacted
+
return pdu
def errback(failure, pdu):
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index be4f123c54..da18bf23db 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -12,7 +12,7 @@
# 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 synapse.events import spamcheck
from twisted.internet import defer
from synapse.api.constants import EventTypes, Membership
@@ -321,6 +321,12 @@ class MessageHandler(BaseHandler):
token_id=requester.access_token_id,
txn_id=txn_id
)
+
+ if spamcheck.check_event_for_spam(event):
+ raise SynapseError(
+ 403, "Spam is not permitted here", Codes.FORBIDDEN
+ )
+
yield self.send_nonmember_event(
requester,
event,
|
