Remove fetching keys via the deprecated v1 kex method

changelog.d/4120.removal

@@ -0,0 +1 @@
+Synapse will no longer fetch keys using the fallback deprecated v1 key exchange method and will now always use v2.

synapse/crypto/keyclient.py

@@ -15,6 +15,8 @@
 
 import logging
 
+from six.moves import urllib
+
 from canonicaljson import json
 
 from twisted.internet import defer, reactor
@@ -28,15 +30,15 @@
 
 logger = logging.getLogger(__name__)
 
-KEY_API_V1 = b"/_matrix/key/v1/"
+KEY_API_V2 = "/_matrix/key/v2/server/%s"
 
 
 @defer.inlineCallbacks
-def fetch_server_key(server_name, tls_client_options_factory, path=KEY_API_V1):
+def fetch_server_key(server_name, tls_client_options_factory, key_id):
  """Fetch the keys for a remote server."""
 
  factory = SynapseKeyClientFactory()
- factory.path = path
+ factory.path = KEY_API_V2 % (urllib.parse.quote(key_id), )
  factory.host = server_name
  endpoint = matrix_federation_endpoint(
  reactor, server_name, tls_client_options_factory, timeout=30

synapse/crypto/keyring.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
-# Copyright 2017 New Vector Ltd.
+# Copyright 2017, 2018 New Vector Ltd.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -18,8 +18,6 @@
 import logging
 from collections import namedtuple
 
-from six.moves import urllib
-
 from signedjson.key import (
  decode_verify_key_bytes,
  encode_verify_key_base64,
@@ -395,32 +393,13 @@ def get_key(perspective_name, perspective_keys):
 
  @defer.inlineCallbacks
  def get_keys_from_server(self, server_name_and_key_ids):
- @defer.inlineCallbacks
- def get_key(server_name, key_ids):
- keys = None
- try:
- keys = yield self.get_server_verify_key_v2_direct(
- server_name, key_ids
- )
- except Exception as e:
- logger.info(
- "Unable to get key %r for %r directly: %s %s",
- key_ids, server_name,
- type(e).__name__, str(e),
- )
-
- if not keys:
- keys = yield self.get_server_verify_key_v1_direct(
- server_name, key_ids
- )
-
- keys = {server_name: keys}
-
- defer.returnValue(keys)
-
  results = yield logcontext.make_deferred_yieldable(defer.gatherResults(
  [
- run_in_background(get_key, server_name, key_ids)
+ run_in_background(
+ self.get_server_verify_key_v2_direct,
+ server_name,
+ key_ids,
+ )
  for server_name, key_ids in server_name_and_key_ids
  ],
  consumeErrors=True,
@@ -525,10 +504,7 @@ def get_server_verify_key_v2_direct(self, server_name, key_ids):
  continue
 
  (response, tls_certificate) = yield fetch_server_key(
- server_name, self.hs.tls_client_options_factory,
- path=("/_matrix/key/v2/server/%s" % (
- urllib.parse.quote(requested_key_id),
- )).encode("ascii"),
+ server_name, self.hs.tls_client_options_factory, requested_key_id
  )
 
  if (u"signatures" not in response
@@ -657,78 +633,6 @@ def process_v2_response(self, from_server, response_json,
 
  defer.returnValue(results)
 
- @defer.inlineCallbacks
- def get_server_verify_key_v1_direct(self, server_name, key_ids):
- """Finds a verification key for the server with one of the key ids.
- Args:
- server_name (str): The name of the server to fetch a key for.
- keys_ids (list of str): The key_ids to check for.
- """
-
- # Try to fetch the key from the remote server.
-
- (response, tls_certificate) = yield fetch_server_key(
- server_name, self.hs.tls_client_options_factory
- )
-
- # Check the response.
-
- x509_certificate_bytes = crypto.dump_certificate(
- crypto.FILETYPE_ASN1, tls_certificate
- )
-
- if ("signatures" not in response
- or server_name not in response["signatures"]):
- raise KeyLookupError("Key response not signed by remote server")
-
- if "tls_certificate" not in response:
- raise KeyLookupError("Key response missing TLS certificate")
-
- tls_certificate_b64 = response["tls_certificate"]
-
- if encode_base64(x509_certificate_bytes) != tls_certificate_b64:
- raise KeyLookupError("TLS certificate doesn't match")
-
- # Cache the result in the datastore.
-
- time_now_ms = self.clock.time_msec()
-
- verify_keys = {}
- for key_id, key_base64 in response["verify_keys"].items():
- if is_signing_algorithm_supported(key_id):
- key_bytes = decode_base64(key_base64)
- verify_key = decode_verify_key_bytes(key_id, key_bytes)
- verify_key.time_added = time_now_ms
- verify_keys[key_id] = verify_key
-
- for key_id in response["signatures"][server_name]:
- if key_id not in response["verify_keys"]:
- raise KeyLookupError(
- "Key response must include verification keys for all"
- " signatures"
- )
- if key_id in verify_keys:
- verify_signed_json(
- response,
- server_name,
- verify_keys[key_id]
- )
-
- yield self.store.store_server_certificate(
- server_name,
- server_name,
- time_now_ms,
- tls_certificate,
- )
-
- yield self.store_keys(
- server_name=server_name,
- from_server=server_name,
- verify_keys=verify_keys,
- )
-
- defer.returnValue(verify_keys)
-
  def store_keys(self, server_name, from_server, verify_keys):
  """Store a collection of verify keys for a given server
  Args: