1 files changed, 160 insertions, 0 deletions
diff --git a/synapse/crypto/resource/key.py b/synapse/crypto/resource/key.py
new file mode 100644
index 0000000000..6ce6e0b034
--- /dev/null
+++ b/synapse/crypto/resource/key.py
@@ -0,0 +1,160 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 matrix.org
+#
+# 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.
+
+from twisted.web.resource import Resource
+from twisted.web.server import NOT_DONE_YET
+from twisted.internet import defer
+from synapse.http.server import respond_with_json_bytes
+from synapse.crypto.keyclient import fetch_server_key
+from syutil.crypto.jsonsign import sign_json, verify_signed_json
+from syutil.base64util import encode_base64, decode_base64
+from syutil.jsonutil import encode_canonical_json
+from OpenSSL import crypto
+from nacl.signing import VerifyKey
+import logging
+
+
+logger = logging.getLogger(__name__)
+
+
+class LocalKey(Resource):
+    """HTTP resource containing encoding the TLS X.509 certificate and NACL
+    signature verification keys for this server::
+
+        GET /key HTTP/1.1
+
+        HTTP/1.1 200 OK
+        Content-Type: application/json
+        {
+            "server_name": "this.server.example.com"
+            "signature_verify_key": # base64 encoded NACL verification key.
+            "tls_certificate": # base64 ASN.1 DER encoded X.509 tls cert.
+            "signatures": {
+                "this.server.example.com": # NACL signature for this server.
+            }
+        }
+    """
+
+    def __init__(self, key_server):
+        self.key_server = key_server
+        self.response_body = encode_canonical_json(
+            self.response_json_object(key_server)
+        )
+        Resource.__init__(self)
+
+    @staticmethod
+    def response_json_object(key_server):
+        verify_key_bytes = key_server.signing_key.verify_key.encode()
+        x509_certificate_bytes = crypto.dump_certificate(
+            crypto.FILETYPE_ASN1,
+            key_server.tls_certificate
+        )
+        json_object = {
+            u"server_name": key_server.server_name,
+            u"signature_verify_key": encode_base64(verify_key_bytes),
+            u"tls_certificate": encode_base64(x509_certificate_bytes)
+        }
+        signed_json = sign_json(
+            json_object,
+            key_server.server_name,
+            key_server.signing_key
+        )
+        return signed_json
+
+    def getChild(self, name, request):
+        logger.info("getChild %s %s", name, request)
+        if name == '':
+            return self
+        else:
+            return RemoteKey(name, self.key_server)
+
+    def render_GET(self, request):
+        return respond_with_json_bytes(request, 200, self.response_body)
+
+
+class RemoteKey(Resource):
+    """HTTP resource for retreiving the TLS certificate and NACL signature
+    verification keys for a another server. Checks that the reported X.509 TLS
+    certificate matches the one used in the HTTPS connection. Checks that the
+    NACL signature for the remote server is valid. Returns JSON signed by both
+    the remote server and by this server.
+
+    GET /key/remote.server.example.com HTTP/1.1
+
+    HTTP/1.1 200 OK
+    Content-Type: application/json
+    {
+        "server_name": "remote.server.example.com"
+        "signature_verify_key": # base64 encoded NACL verification key.
+        "tls_certificate": # base64 ASN.1 DER encoded X.509 tls cert.
+        "signatures": {
+            "remote.server.example.com": # NACL signature for remote server.
+            "this.server.example.com": # NACL signature for this server.
+        }
+    }
+    """
+
+    isLeaf = True
+
+    def __init__(self, server_name, key_server):
+        self.server_name = server_name
+        self.key_server = key_server
+        Resource.__init__(self)
+
+    def render_GET(self, request):
+        self._async_render_GET(request)
+        return NOT_DONE_YET
+
+    @defer.inlineCallbacks
+    def _async_render_GET(self, request):
+        try:
+            server_keys, certificate = yield fetch_server_key(
+                self.server_name,
+                self.key_server.ssl_context_factory
+            )
+
+            resp_server_name = server_keys[u"server_name"]
+            verify_key_b64 = server_keys[u"signature_verify_key"]
+            tls_certificate_b64 = server_keys[u"tls_certificate"]
+            verify_key = VerifyKey(decode_base64(verify_key_b64))
+
+            if resp_server_name != self.server_name:
+                raise ValueError("Wrong server name '%s' != '%s'" %
+                                 (resp_server_name, self.server_name))
+
+            x509_certificate_bytes = crypto.dump_certificate(
+                crypto.FILETYPE_ASN1,
+                certificate
+            )
+
+            if encode_base64(x509_certificate_bytes) != tls_certificate_b64:
+                raise ValueError("TLS certificate doesn't match")
+
+            verify_signed_json(server_keys, self.server_name, verify_key)
+
+            signed_json = sign_json(
+                server_keys,
+                self.key_server.server_name,
+                self.key_server.signing_key
+            )
+
+            json_bytes = encode_canonical_json(signed_json)
+            respond_with_json_bytes(request, 200, json_bytes)
+
+        except Exception as e:
+            json_bytes = encode_canonical_json({
+                u"error": {u"code": 502, u"message": e.message}
+            })
+            respond_with_json_bytes(request, 502, json_bytes)