Ratelimit cross-user key sharing requests. (#8957)

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Patrick Cloke 2021-02-19 13:20:34 -05:00 committed by GitHub
parent 179c0953ff
commit fc8b3d8809
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9 changed files with 67 additions and 17 deletions

1
changelog.d/8957.feature Normal file
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@ -0,0 +1 @@
Add rate limiters to cross-user key sharing requests.

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@ -98,11 +98,14 @@ class EventTypes:
Retention = "m.room.retention"
Presence = "m.presence"
Dummy = "org.matrix.dummy_event"
class EduTypes:
Presence = "m.presence"
RoomKeyRequest = "m.room_key_request"
class RejectedReason:
AUTH_ERROR = "auth_error"

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@ -14,7 +14,7 @@
# limitations under the License.
from collections import OrderedDict
from typing import Any, Optional, Tuple
from typing import Hashable, Optional, Tuple
from synapse.api.errors import LimitExceededError
from synapse.types import Requester
@ -42,7 +42,9 @@ class Ratelimiter:
# * How many times an action has occurred since a point in time
# * The point in time
# * The rate_hz of this particular entry. This can vary per request
self.actions = OrderedDict() # type: OrderedDict[Any, Tuple[float, int, float]]
self.actions = (
OrderedDict()
) # type: OrderedDict[Hashable, Tuple[float, int, float]]
def can_requester_do_action(
self,
@ -82,7 +84,7 @@ class Ratelimiter:
def can_do_action(
self,
key: Any,
key: Hashable,
rate_hz: Optional[float] = None,
burst_count: Optional[int] = None,
update: bool = True,
@ -175,7 +177,7 @@ class Ratelimiter:
def ratelimit(
self,
key: Any,
key: Hashable,
rate_hz: Optional[float] = None,
burst_count: Optional[int] = None,
update: bool = True,

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@ -102,6 +102,16 @@ class RatelimitConfig(Config):
defaults={"per_second": 0.01, "burst_count": 3},
)
# Ratelimit cross-user key requests:
# * For local requests this is keyed by the sending device.
# * For requests received over federation this is keyed by the origin.
#
# Note that this isn't exposed in the configuration as it is obscure.
self.rc_key_requests = RateLimitConfig(
config.get("rc_key_requests", {}),
defaults={"per_second": 20, "burst_count": 100},
)
self.rc_3pid_validation = RateLimitConfig(
config.get("rc_3pid_validation") or {},
defaults={"per_second": 0.003, "burst_count": 5},

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@ -34,7 +34,7 @@ from twisted.internet import defer
from twisted.internet.abstract import isIPAddress
from twisted.python import failure
from synapse.api.constants import EventTypes, Membership
from synapse.api.constants import EduTypes, EventTypes, Membership
from synapse.api.errors import (
AuthError,
Codes,
@ -44,6 +44,7 @@ from synapse.api.errors import (
SynapseError,
UnsupportedRoomVersionError,
)
from synapse.api.ratelimiting import Ratelimiter
from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
from synapse.events import EventBase
from synapse.federation.federation_base import FederationBase, event_from_pdu_json
@ -869,6 +870,13 @@ class FederationHandlerRegistry:
# EDU received.
self._edu_type_to_instance = {} # type: Dict[str, List[str]]
# A rate limiter for incoming room key requests per origin.
self._room_key_request_rate_limiter = Ratelimiter(
clock=self.clock,
rate_hz=self.config.rc_key_requests.per_second,
burst_count=self.config.rc_key_requests.burst_count,
)
def register_edu_handler(
self, edu_type: str, handler: Callable[[str, JsonDict], Awaitable[None]]
):
@ -917,7 +925,15 @@ class FederationHandlerRegistry:
self._edu_type_to_instance[edu_type] = instance_names
async def on_edu(self, edu_type: str, origin: str, content: dict):
if not self.config.use_presence and edu_type == "m.presence":
if not self.config.use_presence and edu_type == EduTypes.Presence:
return
# If the incoming room key requests from a particular origin are over
# the limit, drop them.
if (
edu_type == EduTypes.RoomKeyRequest
and not self._room_key_request_rate_limiter.can_do_action(origin)
):
return
# Check if we have a handler on this instance

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@ -16,7 +16,9 @@
import logging
from typing import TYPE_CHECKING, Any, Dict
from synapse.api.constants import EduTypes
from synapse.api.errors import SynapseError
from synapse.api.ratelimiting import Ratelimiter
from synapse.logging.context import run_in_background
from synapse.logging.opentracing import (
get_active_span_text_map,
@ -25,7 +27,7 @@ from synapse.logging.opentracing import (
start_active_span,
)
from synapse.replication.http.devices import ReplicationUserDevicesResyncRestServlet
from synapse.types import JsonDict, UserID, get_domain_from_id
from synapse.types import JsonDict, Requester, UserID, get_domain_from_id
from synapse.util import json_encoder
from synapse.util.stringutils import random_string
@ -78,6 +80,12 @@ class DeviceMessageHandler:
ReplicationUserDevicesResyncRestServlet.make_client(hs)
)
self._ratelimiter = Ratelimiter(
clock=hs.get_clock(),
rate_hz=hs.config.rc_key_requests.per_second,
burst_count=hs.config.rc_key_requests.burst_count,
)
async def on_direct_to_device_edu(self, origin: str, content: JsonDict) -> None:
local_messages = {}
sender_user_id = content["sender"]
@ -168,15 +176,27 @@ class DeviceMessageHandler:
async def send_device_message(
self,
sender_user_id: str,
requester: Requester,
message_type: str,
messages: Dict[str, Dict[str, JsonDict]],
) -> None:
sender_user_id = requester.user.to_string()
set_tag("number_of_messages", len(messages))
set_tag("sender", sender_user_id)
local_messages = {}
remote_messages = {} # type: Dict[str, Dict[str, Dict[str, JsonDict]]]
for user_id, by_device in messages.items():
# Ratelimit local cross-user key requests by the sending device.
if (
message_type == EduTypes.RoomKeyRequest
and user_id != sender_user_id
and self._ratelimiter.can_do_action(
(sender_user_id, requester.device_id)
)
):
continue
# we use UserID.from_string to catch invalid user ids
if self.is_mine(UserID.from_string(user_id)):
messages_by_device = {

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@ -17,7 +17,7 @@ import logging
import random
from typing import TYPE_CHECKING, Iterable, List, Optional
from synapse.api.constants import EventTypes, Membership
from synapse.api.constants import EduTypes, EventTypes, Membership
from synapse.api.errors import AuthError, SynapseError
from synapse.events import EventBase
from synapse.handlers.presence import format_user_presence_state
@ -113,7 +113,7 @@ class EventStreamHandler(BaseHandler):
states = await presence_handler.get_states(users)
to_add.extend(
{
"type": EventTypes.Presence,
"type": EduTypes.Presence,
"content": format_user_presence_state(state, time_now),
}
for state in states

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@ -18,7 +18,7 @@ from typing import TYPE_CHECKING, Optional, Tuple
from twisted.internet import defer
from synapse.api.constants import EventTypes, Membership
from synapse.api.constants import EduTypes, EventTypes, Membership
from synapse.api.errors import SynapseError
from synapse.events.validator import EventValidator
from synapse.handlers.presence import format_user_presence_state
@ -412,7 +412,7 @@ class InitialSyncHandler(BaseHandler):
return [
{
"type": EventTypes.Presence,
"type": EduTypes.Presence,
"content": format_user_presence_state(s, time_now),
}
for s in states

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@ -56,10 +56,8 @@ class SendToDeviceRestServlet(servlet.RestServlet):
content = parse_json_object_from_request(request)
assert_params_in_dict(content, ("messages",))
sender_user_id = requester.user.to_string()
await self.device_message_handler.send_device_message(
sender_user_id, message_type, content["messages"]
requester, message_type, content["messages"]
)
response = (200, {}) # type: Tuple[int, dict]