diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index 9e017116a9..c708c35d4d 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -20,7 +20,11 @@ from twisted.internet import defer
from synapse.api import errors
from synapse.api.constants import EventTypes
-from synapse.api.errors import FederationDeniedError
+from synapse.api.errors import (
+ FederationDeniedError,
+ HttpResponseException,
+ RequestSendFailed,
+)
from synapse.types import RoomStreamToken, get_domain_from_id
from synapse.util import stringutils
from synapse.util.async_helpers import Linearizer
@@ -504,13 +508,13 @@ class DeviceListEduUpdater(object):
origin = get_domain_from_id(user_id)
try:
result = yield self.federation.query_user_devices(origin, user_id)
- except NotRetryingDestination:
+ except (
+ NotRetryingDestination, RequestSendFailed, HttpResponseException,
+ ):
# TODO: Remember that we are now out of sync and try again
# later
logger.warn(
- "Failed to handle device list update for %s,"
- " we're not retrying the remote",
- user_id,
+ "Failed to handle device list update for %s", user_id,
)
# We abort on exceptions rather than accepting the update
# as otherwise synapse will 'forget' that its device list
@@ -532,6 +536,25 @@ class DeviceListEduUpdater(object):
stream_id = result["stream_id"]
devices = result["devices"]
+
+ # If the remote server has more than ~1000 devices for this user
+ # we assume that something is going horribly wrong (e.g. a bot
+ # that logs in and creates a new device every time it tries to
+ # send a message). Maintaining lots of devices per user in the
+ # cache can cause serious performance issues as if this request
+ # takes more than 60s to complete, internal replication from the
+ # inbound federation worker to the synapse master may time out
+ # causing the inbound federation to fail and causing the remote
+ # server to retry, causing a DoS. So in this scenario we give
+ # up on storing the total list of devices and only handle the
+ # delta instead.
+ if len(devices) > 1000:
+ logger.warn(
+ "Ignoring device list snapshot for %s as it has >1K devs (%d)",
+ user_id, len(devices)
+ )
+ devices = []
+
yield self.store.update_remote_device_list_cache(
user_id, devices, stream_id,
)
|
