SYN-75 Verify signatures on server to server transactions

synapse/crypto/keyclient.py

@@ -15,9 +15,10 @@
 
 
 from twisted.web.http import HTTPClient
+from twisted.internet.protocol import Factory
 from twisted.internet import defer, reactor
-from twisted.internet.protocol import ClientFactory
-from twisted.names.srvconnect import SRVConnector
+from twisted.internet.endpoints import connectProtocol
+from synapse.http.endpoint import matrix_endpoint
 import json
 import logging
 
@@ -30,15 +31,19 @@ def fetch_server_key(server_name, ssl_context_factory):
     """Fetch the keys for a remote server."""
 
     factory = SynapseKeyClientFactory()
+    endpoint = matrix_endpoint(
+        reactor, server_name, ssl_context_factory, timeout=30
+    )
 
-    SRVConnector(
-        reactor, "matrix", server_name, factory,
-        protocol="tcp", connectFuncName="connectSSL", defaultPort=443,
-        connectFuncKwArgs=dict(contextFactory=ssl_context_factory)).connect()
-
-    server_key, server_certificate = yield factory.remote_key
-
-    defer.returnValue((server_key, server_certificate))
+    for i in range(5):
+        try:
+            protocol = yield endpoint.connect(factory)
+            server_response, server_certificate = yield protocol.remote_key
+            defer.returnValue((server_response, server_certificate))
+            return
+        except Exception as e:
+            logger.exception(e)
+    raise IOError("Cannot get key for " % server_name)
 
 
 class SynapseKeyClientError(Exception):
@@ -51,69 +56,47 @@ class SynapseKeyClientProtocol(HTTPClient):
     the server and extracts the X.509 certificate for the remote peer from the
     SSL connection."""
 
+    timeout = 30
+
+    def __init__(self):
+        self.remote_key = defer.Deferred()
+
     def connectionMade(self):
         logger.debug("Connected to %s", self.transport.getHost())
-        self.sendCommand(b"GET", b"/key")
+        self.sendCommand(b"GET", b"/_matrix/key/v1/")
         self.endHeaders()
         self.timer = reactor.callLater(
-            self.factory.timeout_seconds,
+            self.timeout,
             self.on_timeout
         )
 
     def handleStatus(self, version, status, message):
         if status != b"200":
-            logger.info("Non-200 response from %s: %s %s",
-                        self.transport.getHost(), status, message)
+            #logger.info("Non-200 response from %s: %s %s",
+            #            self.transport.getHost(), status, message)
             self.transport.abortConnection()
 
     def handleResponse(self, response_body_bytes):
         try:
             json_response = json.loads(response_body_bytes)
         except ValueError:
-            logger.info("Invalid JSON response from %s",
-                        self.transport.getHost())
+            #logger.info("Invalid JSON response from %s",
+            #            self.transport.getHost())
             self.transport.abortConnection()
             return
 
         certificate = self.transport.getPeerCertificate()
-        self.factory.on_remote_key((json_response, certificate))
+        self.remote_key.callback((json_response, certificate))
         self.transport.abortConnection()
         self.timer.cancel()
 
     def on_timeout(self):
         logger.debug("Timeout waiting for response from %s",
                      self.transport.getHost())
+        self.on_remote_key.errback(IOError("Timeout waiting for response"))
         self.transport.abortConnection()
 
 
-class SynapseKeyClientFactory(ClientFactory):
+class SynapseKeyClientFactory(Factory):
     protocol = SynapseKeyClientProtocol
-    max_retries = 5
-    timeout_seconds = 30
 
-    def __init__(self):
-        self.succeeded = False
-        self.retries = 0
-        self.remote_key = defer.Deferred()
-
-    def on_remote_key(self, key):
-        self.succeeded = True
-        self.remote_key.callback(key)
-
-    def retry_connection(self, connector):
-        self.retries += 1
-        if self.retries < self.max_retries:
-            connector.connector = None
-            connector.connect()
-        else:
-            self.remote_key.errback(
-                SynapseKeyClientError("Max retries exceeded"))
-
-    def clientConnectionFailed(self, connector, reason):
-        logger.info("Connection failed %s", reason)
-        self.retry_connection(connector)
-
-    def clientConnectionLost(self, connector, reason):
-        logger.info("Connection lost %s", reason)
-        if not self.succeeded:
-            self.retry_connection(connector)