3 files changed, 53 insertions, 9 deletions
diff --git a/synapse/crypto/context_factory.py b/synapse/crypto/context_factory.py
index 0397f73ab4..57694e18b0 100644
--- a/synapse/crypto/context_factory.py
+++ b/synapse/crypto/context_factory.py
@@ -11,17 +11,19 @@
 # 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 twisted.internet import ssl
 from OpenSSL import SSL, crypto
-from twisted.internet._sslverify import _defaultCurveName
-
-import logging
+from twisted.internet._idna import _idnaBytes
+from twisted.internet.ssl import ContextFactory, CertificateOptions
+from twisted.internet._sslverify import _defaultCurveName, _tolerateErrors
+from twisted.internet.interfaces import IOpenSSLClientConnectionCreator
+from zope.interface import implementer
 
 logger = logging.getLogger(__name__)
 
 
-class ServerContextFactory(ssl.ContextFactory):
+class ServerContextFactory(ContextFactory):
     """Factory for PyOpenSSL SSL contexts that are used to handle incoming
     connections and to make connections to remote servers."""
 
@@ -48,3 +50,45 @@ class ServerContextFactory(ssl.ContextFactory):
 
     def getContext(self):
         return self._context
+
+
+@implementer(IOpenSSLClientConnectionCreator)
+class ClientTLSOptions(object):
+    """
+    Client creator for TLS without certificate identity verification. This is a
+    copy of twisted.internet._sslverify.ClientTLSOptions with the identity
+    verification left out. For documentation, see the twisted documentation.
+    """
+
+    def __init__(self, hostname, ctx):
+        self._ctx = ctx
+        self._hostname = hostname
+        self._hostnameBytes = _idnaBytes(hostname)
+        ctx.set_info_callback(
+            _tolerateErrors(self._identityVerifyingInfoCallback)
+        )
+
+    def clientConnectionForTLS(self, tlsProtocol):
+        context = self._ctx
+        connection = SSL.Connection(context, None)
+        connection.set_app_data(tlsProtocol)
+        return connection
+
+    def _identityVerifyingInfoCallback(self, connection, where, ret):
+        if where & SSL.SSL_CB_HANDSHAKE_START:
+            connection.set_tlsext_host_name(self._hostnameBytes)
+
+
+class ClientTLSOptionsFactory(object):
+    """Factory for Twisted ClientTLSOptions that are used to make connections
+    to remote servers for federation."""
+
+    def __init__(self, config):
+        # We don't use config options yet
+        pass
+
+    def get_options(self, host):
+        return ClientTLSOptions(
+            unicode(host),
+            CertificateOptions(verify=False).getContext()
+        )
diff --git a/synapse/crypto/keyclient.py b/synapse/crypto/keyclient.py
index 2a0eddbea1..e13cab9dbf 100644
--- a/synapse/crypto/keyclient.py
+++ b/synapse/crypto/keyclient.py
@@ -28,14 +28,14 @@ KEY_API_V1 = b"/_matrix/key/v1/"
 
 
 @defer.inlineCallbacks
-def fetch_server_key(server_name, ssl_context_factory, path=KEY_API_V1):
+def fetch_server_key(server_name, tls_client_options_factory, path=KEY_API_V1):
     """Fetch the keys for a remote server."""
 
     factory = SynapseKeyClientFactory()
     factory.path = path
     factory.host = server_name
     endpoint = matrix_federation_endpoint(
-        reactor, server_name, ssl_context_factory, timeout=30
+        reactor, server_name, tls_client_options_factory, timeout=30
     )
 
     for i in range(5):
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index 9b17ef0a08..9a1bb211fb 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -510,7 +510,7 @@ class Keyring(object):
                 continue
 
             (response, tls_certificate) = yield fetch_server_key(
-                server_name, self.hs.tls_server_context_factory,
+                server_name, self.tls_client_options_factory,
                 path=(b"/_matrix/key/v2/server/%s" % (
                     urllib.quote(requested_key_id),
                 )).encode("ascii"),
@@ -653,7 +653,7 @@ class Keyring(object):
         # Try to fetch the key from the remote server.
 
         (response, tls_certificate) = yield fetch_server_key(
-            server_name, self.hs.tls_server_context_factory
+            server_name, self.hs.tls_client_options_factory
         )
 
         # Check the response.