mirror of
https://mau.dev/maunium/synapse.git
synced 2024-10-01 01:36:05 -04:00
261 lines
9.6 KiB
Python
261 lines
9.6 KiB
Python
# Copyright 2015, 2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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import re
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from typing import TYPE_CHECKING, Dict, Optional, Set, Tuple
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from signedjson.sign import sign_json
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from twisted.web.server import Request
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from synapse.crypto.keyring import ServerKeyFetcher
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from synapse.http.server import HttpServer
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from synapse.http.servlet import (
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RestServlet,
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parse_integer,
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parse_json_object_from_request,
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)
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from synapse.types import JsonDict
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from synapse.util import json_decoder
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from synapse.util.async_helpers import yieldable_gather_results
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if TYPE_CHECKING:
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from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
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class RemoteKey(RestServlet):
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"""HTTP resource for retrieving the TLS certificate and NACL signature
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verification keys for a collection of servers. Checks that the reported
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X.509 TLS certificate matches the one used in the HTTPS connection. Checks
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that the NACL signature for the remote server is valid. Returns a dict of
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JSON signed by both the remote server and by this server.
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Supports individual GET APIs and a bulk query POST API.
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Requests:
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GET /_matrix/key/v2/query/remote.server.example.com HTTP/1.1
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GET /_matrix/key/v2/query/remote.server.example.com/a.key.id HTTP/1.1
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POST /_matrix/v2/query HTTP/1.1
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Content-Type: application/json
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{
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"server_keys": {
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"remote.server.example.com": {
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"a.key.id": {
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"minimum_valid_until_ts": 1234567890123
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}
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}
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}
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}
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Response:
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HTTP/1.1 200 OK
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Content-Type: application/json
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{
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"server_keys": [
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{
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"server_name": "remote.server.example.com"
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"valid_until_ts": # posix timestamp
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"verify_keys": {
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"a.key.id": { # The identifier for a key.
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key: "" # base64 encoded verification key.
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}
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}
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"old_verify_keys": {
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"an.old.key.id": { # The identifier for an old key.
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key: "", # base64 encoded key
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"expired_ts": 0, # when the key stop being used.
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}
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}
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"signatures": {
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"remote.server.example.com": {...}
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"this.server.example.com": {...}
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}
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}
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]
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}
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"""
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def __init__(self, hs: "HomeServer"):
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self.fetcher = ServerKeyFetcher(hs)
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self.store = hs.get_datastores().main
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self.clock = hs.get_clock()
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self.federation_domain_whitelist = (
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hs.config.federation.federation_domain_whitelist
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)
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self.config = hs.config
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def register(self, http_server: HttpServer) -> None:
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http_server.register_paths(
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"GET",
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(
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re.compile(
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"^/_matrix/key/v2/query/(?P<server>[^/]*)(/(?P<key_id>[^/]*))?$"
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),
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),
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self.on_GET,
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self.__class__.__name__,
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)
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http_server.register_paths(
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"POST",
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(re.compile("^/_matrix/key/v2/query$"),),
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self.on_POST,
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self.__class__.__name__,
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)
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async def on_GET(
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self, request: Request, server: str, key_id: Optional[str] = None
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) -> Tuple[int, JsonDict]:
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if server and key_id:
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minimum_valid_until_ts = parse_integer(request, "minimum_valid_until_ts")
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arguments = {}
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if minimum_valid_until_ts is not None:
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arguments["minimum_valid_until_ts"] = minimum_valid_until_ts
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query = {server: {key_id: arguments}}
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else:
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query = {server: {}}
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return 200, await self.query_keys(query, query_remote_on_cache_miss=True)
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async def on_POST(self, request: Request) -> Tuple[int, JsonDict]:
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content = parse_json_object_from_request(request)
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query = content["server_keys"]
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return 200, await self.query_keys(query, query_remote_on_cache_miss=True)
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async def query_keys(
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self, query: JsonDict, query_remote_on_cache_miss: bool = False
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) -> JsonDict:
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logger.info("Handling query for keys %r", query)
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store_queries = []
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for server_name, key_ids in query.items():
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if not key_ids:
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key_ids = (None,)
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for key_id in key_ids:
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store_queries.append((server_name, key_id, None))
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cached = await self.store.get_server_keys_json(store_queries)
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json_results: Set[bytes] = set()
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time_now_ms = self.clock.time_msec()
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# Map server_name->key_id->int. Note that the value of the init is unused.
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# XXX: why don't we just use a set?
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cache_misses: Dict[str, Dict[str, int]] = {}
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for (server_name, key_id, _), key_results in cached.items():
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results = [(result["ts_added_ms"], result) for result in key_results]
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if key_id is None:
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# all keys were requested. Just return what we have without worrying
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# about validity
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for _, result in results:
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# Cast to bytes since postgresql returns a memoryview.
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json_results.add(bytes(result["key_json"]))
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continue
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miss = False
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if not results:
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miss = True
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else:
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ts_added_ms, most_recent_result = max(results)
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ts_valid_until_ms = most_recent_result["ts_valid_until_ms"]
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req_key = query.get(server_name, {}).get(key_id, {})
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req_valid_until = req_key.get("minimum_valid_until_ts")
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if req_valid_until is not None:
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if ts_valid_until_ms < req_valid_until:
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logger.debug(
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"Cached response for %r/%r is older than requested"
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": valid_until (%r) < minimum_valid_until (%r)",
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server_name,
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key_id,
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ts_valid_until_ms,
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req_valid_until,
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)
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miss = True
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else:
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logger.debug(
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"Cached response for %r/%r is newer than requested"
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": valid_until (%r) >= minimum_valid_until (%r)",
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server_name,
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key_id,
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ts_valid_until_ms,
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req_valid_until,
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)
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elif (ts_added_ms + ts_valid_until_ms) / 2 < time_now_ms:
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logger.debug(
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"Cached response for %r/%r is too old"
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": (added (%r) + valid_until (%r)) / 2 < now (%r)",
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server_name,
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key_id,
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ts_added_ms,
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ts_valid_until_ms,
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time_now_ms,
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)
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# We more than half way through the lifetime of the
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# response. We should fetch a fresh copy.
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miss = True
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else:
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logger.debug(
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"Cached response for %r/%r is still valid"
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": (added (%r) + valid_until (%r)) / 2 < now (%r)",
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server_name,
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key_id,
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ts_added_ms,
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ts_valid_until_ms,
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time_now_ms,
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)
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# Cast to bytes since postgresql returns a memoryview.
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json_results.add(bytes(most_recent_result["key_json"]))
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if miss and query_remote_on_cache_miss:
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# only bother attempting to fetch keys from servers on our whitelist
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if (
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self.federation_domain_whitelist is None
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or server_name in self.federation_domain_whitelist
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):
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cache_misses.setdefault(server_name, {})[key_id] = 0
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# If there is a cache miss, request the missing keys, then recurse (and
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# ensure the result is sent).
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if cache_misses:
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await yieldable_gather_results(
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lambda t: self.fetcher.get_keys(*t),
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(
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(server_name, list(keys), 0)
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for server_name, keys in cache_misses.items()
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),
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)
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return await self.query_keys(query, query_remote_on_cache_miss=False)
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else:
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signed_keys = []
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for key_json_raw in json_results:
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key_json = json_decoder.decode(key_json_raw.decode("utf-8"))
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for signing_key in self.config.key.key_server_signing_keys:
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key_json = sign_json(
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key_json, self.config.server.server_name, signing_key
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)
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signed_keys.append(key_json)
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return {"server_keys": signed_keys}
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