forked-synapse/synapse/handlers/devicemessage.py
Shay 641ff9ef7e
Support MSC3814: Dehydrated Devices (#15929)
Signed-off-by: Nicolas Werner <n.werner@famedly.com>
Co-authored-by: Nicolas Werner <n.werner@famedly.com>
Co-authored-by: Nicolas Werner <89468146+nico-famedly@users.noreply.github.com>
Co-authored-by: Hubert Chathi <hubert@uhoreg.ca>
2023-07-24 08:23:19 -07:00

410 lines
16 KiB
Python

# Copyright 2016 OpenMarket 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.
import logging
from http import HTTPStatus
from typing import TYPE_CHECKING, Any, Dict, Optional
from synapse.api.constants import EduTypes, EventContentFields, ToDeviceEventTypes
from synapse.api.errors import Codes, SynapseError
from synapse.api.ratelimiting import Ratelimiter
from synapse.logging.context import run_in_background
from synapse.logging.opentracing import (
SynapseTags,
get_active_span_text_map,
log_kv,
set_tag,
)
from synapse.replication.http.devices import (
ReplicationMultiUserDevicesResyncRestServlet,
)
from synapse.types import JsonDict, Requester, StreamKeyType, UserID, get_domain_from_id
from synapse.util import json_encoder
from synapse.util.stringutils import random_string
if TYPE_CHECKING:
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
class DeviceMessageHandler:
def __init__(self, hs: "HomeServer"):
"""
Args:
hs: server
"""
self.store = hs.get_datastores().main
self.notifier = hs.get_notifier()
self.is_mine = hs.is_mine
if hs.config.experimental.msc3814_enabled:
self.event_sources = hs.get_event_sources()
self.device_handler = hs.get_device_handler()
# We only need to poke the federation sender explicitly if its on the
# same instance. Other federation sender instances will get notified by
# `synapse.app.generic_worker.FederationSenderHandler` when it sees it
# in the to-device replication stream.
self.federation_sender = None
if hs.should_send_federation():
self.federation_sender = hs.get_federation_sender()
# If we can handle the to device EDUs we do so, otherwise we route them
# to the appropriate worker.
if hs.get_instance_name() in hs.config.worker.writers.to_device:
hs.get_federation_registry().register_edu_handler(
EduTypes.DIRECT_TO_DEVICE, self.on_direct_to_device_edu
)
else:
hs.get_federation_registry().register_instances_for_edu(
EduTypes.DIRECT_TO_DEVICE,
hs.config.worker.writers.to_device,
)
# The handler to call when we think a user's device list might be out of
# sync. We do all device list resyncing on the master instance, so if
# we're on a worker we hit the device resync replication API.
if hs.config.worker.worker_app is None:
self._multi_user_device_resync = (
hs.get_device_handler().device_list_updater.multi_user_device_resync
)
else:
self._multi_user_device_resync = (
ReplicationMultiUserDevicesResyncRestServlet.make_client(hs)
)
# a rate limiter for room key requests. The keys are
# (sending_user_id, sending_device_id).
self._ratelimiter = Ratelimiter(
store=self.store,
clock=hs.get_clock(),
rate_hz=hs.config.ratelimiting.rc_key_requests.per_second,
burst_count=hs.config.ratelimiting.rc_key_requests.burst_count,
)
async def on_direct_to_device_edu(self, origin: str, content: JsonDict) -> None:
"""
Handle receiving to-device messages from remote homeservers.
Args:
origin: The remote homeserver.
content: The JSON dictionary containing the to-device messages.
"""
local_messages = {}
sender_user_id = content["sender"]
if origin != get_domain_from_id(sender_user_id):
logger.warning(
"Dropping device message from %r with spoofed sender %r",
origin,
sender_user_id,
)
message_type = content["type"]
message_id = content["message_id"]
for user_id, by_device in content["messages"].items():
# we use UserID.from_string to catch invalid user ids
if not self.is_mine(UserID.from_string(user_id)):
logger.warning("To-device message to non-local user %s", user_id)
raise SynapseError(400, "Not a user here")
if not by_device:
continue
# Ratelimit key requests by the sending user.
if message_type == ToDeviceEventTypes.RoomKeyRequest:
allowed, _ = await self._ratelimiter.can_do_action(
None, (sender_user_id, None)
)
if not allowed:
logger.info(
"Dropping room_key_request from %s to %s due to rate limit",
sender_user_id,
user_id,
)
continue
messages_by_device = {
device_id: {
"content": message_content,
"type": message_type,
"sender": sender_user_id,
}
for device_id, message_content in by_device.items()
}
local_messages[user_id] = messages_by_device
await self._check_for_unknown_devices(
message_type, sender_user_id, by_device
)
# Add messages to the database.
# Retrieve the stream id of the last-processed to-device message.
last_stream_id = await self.store.add_messages_from_remote_to_device_inbox(
origin, message_id, local_messages
)
# Notify listeners that there are new to-device messages to process,
# handing them the latest stream id.
self.notifier.on_new_event(
StreamKeyType.TO_DEVICE, last_stream_id, users=local_messages.keys()
)
async def _check_for_unknown_devices(
self,
message_type: str,
sender_user_id: str,
by_device: Dict[str, Dict[str, Any]],
) -> None:
"""Checks inbound device messages for unknown remote devices, and if
found marks the remote cache for the user as stale.
"""
if message_type != "m.room_key_request":
return
# Get the sending device IDs
requesting_device_ids = set()
for message_content in by_device.values():
device_id = message_content.get("requesting_device_id")
requesting_device_ids.add(device_id)
# Check if we are tracking the devices of the remote user.
room_ids = await self.store.get_rooms_for_user(sender_user_id)
if not room_ids:
logger.info(
"Received device message from remote device we don't"
" share a room with: %s %s",
sender_user_id,
requesting_device_ids,
)
return
# If we are tracking check that we know about the sending
# devices.
cached_devices = await self.store.get_cached_devices_for_user(sender_user_id)
unknown_devices = requesting_device_ids - set(cached_devices)
if unknown_devices:
logger.info(
"Received device message from remote device not in our cache: %s %s",
sender_user_id,
unknown_devices,
)
await self.store.mark_remote_users_device_caches_as_stale((sender_user_id,))
# Immediately attempt a resync in the background
run_in_background(self._multi_user_device_resync, user_ids=[sender_user_id])
async def send_device_message(
self,
requester: Requester,
message_type: str,
messages: Dict[str, Dict[str, JsonDict]],
) -> None:
"""
Handle a request from a user to send to-device message(s).
Args:
requester: The user that is sending the to-device messages.
message_type: The type of to-device messages that are being sent.
messages: A dictionary containing recipients mapped to messages intended for them.
"""
sender_user_id = requester.user.to_string()
set_tag(SynapseTags.TO_DEVICE_TYPE, message_type)
set_tag(SynapseTags.TO_DEVICE_SENDER, sender_user_id)
local_messages = {}
remote_messages: Dict[str, Dict[str, Dict[str, JsonDict]]] = {}
for user_id, by_device in messages.items():
# add an opentracing log entry for each message
for device_id, message_content in by_device.items():
log_kv(
{
"event": "send_to_device_message",
"user_id": user_id,
"device_id": device_id,
EventContentFields.TO_DEVICE_MSGID: message_content.get(
EventContentFields.TO_DEVICE_MSGID
),
}
)
# Ratelimit local cross-user key requests by the sending device.
if (
message_type == ToDeviceEventTypes.RoomKeyRequest
and user_id != sender_user_id
):
allowed, _ = await self._ratelimiter.can_do_action(
requester, (sender_user_id, requester.device_id)
)
if not allowed:
log_kv({"message": f"dropping key requests to {user_id}"})
logger.info(
"Dropping room_key_request from %s to %s due to rate limit",
sender_user_id,
user_id,
)
continue
# we use UserID.from_string to catch invalid user ids
if self.is_mine(UserID.from_string(user_id)):
messages_by_device = {
device_id: {
"content": message_content,
"type": message_type,
"sender": sender_user_id,
}
for device_id, message_content in by_device.items()
}
if messages_by_device:
local_messages[user_id] = messages_by_device
else:
destination = get_domain_from_id(user_id)
remote_messages.setdefault(destination, {})[user_id] = by_device
context = get_active_span_text_map()
remote_edu_contents = {}
for destination, messages in remote_messages.items():
# The EDU contains a "message_id" property which is used for
# idempotence. Make up a random one.
message_id = random_string(16)
log_kv({"destination": destination, "message_id": message_id})
remote_edu_contents[destination] = {
"messages": messages,
"sender": sender_user_id,
"type": message_type,
"message_id": message_id,
"org.matrix.opentracing_context": json_encoder.encode(context),
}
# Add messages to the database.
# Retrieve the stream id of the last-processed to-device message.
last_stream_id = await self.store.add_messages_to_device_inbox(
local_messages, remote_edu_contents
)
# Notify listeners that there are new to-device messages to process,
# handing them the latest stream id.
self.notifier.on_new_event(
StreamKeyType.TO_DEVICE, last_stream_id, users=local_messages.keys()
)
if self.federation_sender:
for destination in remote_messages.keys():
# Enqueue a new federation transaction to send the new
# device messages to each remote destination.
self.federation_sender.send_device_messages(destination)
async def get_events_for_dehydrated_device(
self,
requester: Requester,
device_id: str,
since_token: Optional[str],
limit: int,
) -> JsonDict:
"""Fetches up to `limit` events sent to `device_id` starting from `since_token`
and returns the new since token. If there are no more messages, returns an empty
array.
Args:
requester: the user requesting the messages
device_id: ID of the dehydrated device
since_token: stream id to start from when fetching messages
limit: the number of messages to fetch
Returns:
A dict containing the to-device messages, as well as a token that the client
can provide in the next call to fetch the next batch of messages
"""
user_id = requester.user.to_string()
# only allow fetching messages for the dehydrated device id currently associated
# with the user
dehydrated_device = await self.device_handler.get_dehydrated_device(user_id)
if dehydrated_device is None:
raise SynapseError(
HTTPStatus.FORBIDDEN,
"No dehydrated device exists",
Codes.FORBIDDEN,
)
dehydrated_device_id, _ = dehydrated_device
if device_id != dehydrated_device_id:
raise SynapseError(
HTTPStatus.FORBIDDEN,
"You may only fetch messages for your dehydrated device",
Codes.FORBIDDEN,
)
since_stream_id = 0
if since_token:
if not since_token.startswith("d"):
raise SynapseError(
HTTPStatus.BAD_REQUEST,
"from parameter %r has an invalid format" % (since_token,),
errcode=Codes.INVALID_PARAM,
)
try:
since_stream_id = int(since_token[1:])
except Exception:
raise SynapseError(
HTTPStatus.BAD_REQUEST,
"from parameter %r has an invalid format" % (since_token,),
errcode=Codes.INVALID_PARAM,
)
# if we have a since token, delete any to-device messages before that token
# (since we now know that the device has received them)
deleted = await self.store.delete_messages_for_device(
user_id, device_id, since_stream_id
)
logger.debug(
"Deleted %d to-device messages up to %d for user_id %s device_id %s",
deleted,
since_stream_id,
user_id,
device_id,
)
to_token = self.event_sources.get_current_token().to_device_key
messages, stream_id = await self.store.get_messages_for_device(
user_id, device_id, since_stream_id, to_token, limit
)
for message in messages:
# Remove the message id before sending to client
message_id = message.pop("message_id", None)
if message_id:
set_tag(SynapseTags.TO_DEVICE_EDU_ID, message_id)
logger.debug(
"Returning %d to-device messages between %d and %d (current token: %d) for "
"dehydrated device %s, user_id %s",
len(messages),
since_stream_id,
stream_id,
to_token,
device_id,
user_id,
)
return {
"events": messages,
"next_batch": f"d{stream_id}",
}