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| -rw-r--r-- | synapse/handlers/device.py | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py index 9e017116a9..6f80a7dce9 100644 --- a/synapse/handlers/device.py +++ b/synapse/handlers/device.py @@ -532,6 +532,20 @@ class DeviceListEduUpdater(object): stream_id = result["stream_id"] devices = result["devices"] + + # Emergency hack to prevent DoS from + # @bot:oliviervandertoorn.nl and @bot:matrix-beta.igalia.com + # on Jan 15 2019: only store the most recent 1000 devices for + # a given user. (We assume we receive them in chronological + # order, which is dubious given _get_e2e_device_keys_txn does + # not explicitly order its results). Otherwise it can take + # longer than 60s to persist the >100K devices, at which point + # the internal replication request to handle the + # m.device_list_update EDU times out, causing the remote + # server to retry the transaction and thus DoS synapse master + # CPU and DB. + devices = devices[-1000:] + yield self.store.update_remote_device_list_cache( user_id, devices, stream_id, ) |