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authorRichard van der Hoff <richard@matrix.org>2018-05-01 16:19:39 +0100
committerRichard van der Hoff <richard@matrix.org>2018-05-01 17:54:19 +0100
commit33f469ba19586bbafa0cf2c7d7c35463bdab87eb (patch)
tree10e97f31a3a34eafd12032236805190d2f63d90e /synapse/handlers
parentupdate changelog and bump version to 0.28.0 (diff)
downloadsynapse-33f469ba19586bbafa0cf2c7d7c35463bdab87eb.tar.xz
Apply some limits to depth to counter abuse
* When creating a new event, cap its depth to 2^63 - 1
* When receiving events, reject any without a sensible depth

As per https://docs.google.com/document/d/1I3fi2S-XnpO45qrpCsowZv8P8dHcNZ4fsBsbOW7KABI
Diffstat (limited to '')
-rw-r--r--synapse/handlers/message.py6
1 files changed, 5 insertions, 1 deletions
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 21628a8540..53beb2b9ab 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -16,7 +16,7 @@
 from twisted.internet import defer, reactor
 from twisted.python.failure import Failure
 
-from synapse.api.constants import EventTypes, Membership
+from synapse.api.constants import EventTypes, Membership, MAX_DEPTH
 from synapse.api.errors import AuthError, Codes, SynapseError
 from synapse.crypto.event_signing import add_hashes_and_signatures
 from synapse.events.utils import serialize_event
@@ -624,6 +624,10 @@ class EventCreationHandler(object):
 
         if prev_events_and_hashes:
             depth = max([d for _, _, d in prev_events_and_hashes]) + 1
+            # we cap depth of generated events, to ensure that they are not
+            # rejected by other servers (and so that they can be persisted in
+            # the db)
+            depth = min(depth, MAX_DEPTH)
         else:
             depth = 1