Merge pull request #129 from matrix-org/key_distribution

Key distribution v2

synapse/api/urls.py

@@ -22,5 +22,6 @@
 WEB_CLIENT_PREFIX = "/_matrix/client"
 CONTENT_REPO_PREFIX = "/_matrix/content"
 SERVER_KEY_PREFIX = "/_matrix/key/v1"
+SERVER_KEY_V2_PREFIX = "/_matrix/key/v2"
 MEDIA_PREFIX = "/_matrix/media/v1"
 APP_SERVICE_PREFIX = "/_matrix/appservice/v1"

synapse/app/homeserver.py

@@ -36,10 +36,12 @@
 from synapse.rest.media.v0.content_repository import ContentRepoResource
 from synapse.rest.media.v1.media_repository import MediaRepositoryResource
 from synapse.rest.key.v1.server_key_resource import LocalKey
+from synapse.rest.key.v2 import KeyApiV2Resource
 from synapse.http.matrixfederationclient import MatrixFederationHttpClient
 from synapse.api.urls import (
     CLIENT_PREFIX, FEDERATION_PREFIX, WEB_CLIENT_PREFIX, CONTENT_REPO_PREFIX,
-    SERVER_KEY_PREFIX, MEDIA_PREFIX, CLIENT_V2_ALPHA_PREFIX, STATIC_PREFIX
+    SERVER_KEY_PREFIX, MEDIA_PREFIX, CLIENT_V2_ALPHA_PREFIX, STATIC_PREFIX,
+    SERVER_KEY_V2_PREFIX,
 )
 from synapse.config.homeserver import HomeServerConfig
 from synapse.crypto import context_factory
@@ -97,6 +99,9 @@ def build_resource_for_media_repository(self):
     def build_resource_for_server_key(self):
         return LocalKey(self)
 
+    def build_resource_for_server_key_v2(self):
+        return KeyApiV2Resource(self)
+
     def build_resource_for_metrics(self):
         if self.get_config().enable_metrics:
             return MetricsResource(self)
@@ -134,6 +139,7 @@ def create_resource_tree(self, redirect_root_to_web_client):
             (FEDERATION_PREFIX, self.get_resource_for_federation()),
             (CONTENT_REPO_PREFIX, self.get_resource_for_content_repo()),
             (SERVER_KEY_PREFIX, self.get_resource_for_server_key()),
+            (SERVER_KEY_V2_PREFIX, self.get_resource_for_server_key_v2()),
             (MEDIA_PREFIX, self.get_resource_for_media_repository()),
             (STATIC_PREFIX, self.get_resource_for_static_content()),
         ]

synapse/config/_base.py

@@ -77,6 +77,17 @@ def read_file(cls, file_path, config_name):
         with open(file_path) as file_stream:
             return file_stream.read()
 
+    @classmethod
+    def read_yaml_file(cls, file_path, config_name):
+        cls.check_file(file_path, config_name)
+        with open(file_path) as file_stream:
+            try:
+                return yaml.load(file_stream)
+            except:
+                raise ConfigError(
+                    "Error parsing yaml in file %r" % (file_path,)
+                )
+
     @staticmethod
     def default_path(name):
         return os.path.abspath(os.path.join(os.path.curdir, name))

synapse/config/homeserver.py

@@ -24,12 +24,13 @@
 from .registration import RegistrationConfig
 from .metrics import MetricsConfig
 from .appservice import AppServiceConfig
+from .key import KeyConfig
 
 
 class HomeServerConfig(TlsConfig, ServerConfig, DatabaseConfig, LoggingConfig,
                        RatelimitConfig, ContentRepositoryConfig, CaptchaConfig,
                        VoipConfig, RegistrationConfig,
-                       MetricsConfig, AppServiceConfig,):
+                       MetricsConfig, AppServiceConfig, KeyConfig,):
     pass
 
 

synapse/config/key.py

@@ -0,0 +1,147 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# 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.
+
+import os
+from ._base import Config, ConfigError
+import syutil.crypto.signing_key
+from syutil.crypto.signing_key import (
+    is_signing_algorithm_supported, decode_verify_key_bytes
+)
+from syutil.base64util import decode_base64
+
+
+class KeyConfig(Config):
+
+    def __init__(self, args):
+        super(KeyConfig, self).__init__(args)
+        self.signing_key = self.read_signing_key(args.signing_key_path)
+        self.old_signing_keys = self.read_old_signing_keys(
+            args.old_signing_key_path
+        )
+        self.key_refresh_interval = args.key_refresh_interval
+        self.perspectives = self.read_perspectives(
+            args.perspectives_config_path
+        )
+
+    @classmethod
+    def add_arguments(cls, parser):
+        super(KeyConfig, cls).add_arguments(parser)
+        key_group = parser.add_argument_group("keys")
+        key_group.add_argument("--signing-key-path",
+                               help="The signing key to sign messages with")
+        key_group.add_argument("--old-signing-key-path",
+                               help="The keys that the server used to sign"
+                                    " sign messages with but won't use"
+                                    " to sign new messages. E.g. it has"
+                                    " lost its private key")
+        key_group.add_argument("--key-refresh-interval",
+                               default=24 * 60 * 60 * 1000,  # 1 Day
+                               help="How long a key response is valid for."
+                                    " Used to set the exipiry in /key/v2/."
+                                    " Controls how frequently servers will"
+                                    " query what keys are still valid")
+        key_group.add_argument("--perspectives-config-path",
+                               help="The trusted servers to download signing"
+                                    " keys from")
+
+    def read_perspectives(self, perspectives_config_path):
+        config = self.read_yaml_file(
+            perspectives_config_path, "perspectives_config_path"
+        )
+        servers = {}
+        for server_name, server_config in config["servers"].items():
+            for key_id, key_data in server_config["verify_keys"].items():
+                if is_signing_algorithm_supported(key_id):
+                    key_base64 = key_data["key"]
+                    key_bytes = decode_base64(key_base64)
+                    verify_key = decode_verify_key_bytes(key_id, key_bytes)
+                    servers.setdefault(server_name, {})[key_id] = verify_key
+        return servers
+
+    def read_signing_key(self, signing_key_path):
+        signing_keys = self.read_file(signing_key_path, "signing_key")
+        try:
+            return syutil.crypto.signing_key.read_signing_keys(
+                signing_keys.splitlines(True)
+            )
+        except Exception:
+            raise ConfigError(
+                "Error reading signing_key."
+                " Try running again with --generate-config"
+            )
+
+    def read_old_signing_keys(self, old_signing_key_path):
+        old_signing_keys = self.read_file(
+            old_signing_key_path, "old_signing_key"
+        )
+        try:
+            return syutil.crypto.signing_key.read_old_signing_keys(
+                old_signing_keys.splitlines(True)
+            )
+        except Exception:
+            raise ConfigError(
+                "Error reading old signing keys."
+            )
+
+    @classmethod
+    def generate_config(cls, args, config_dir_path):
+        super(KeyConfig, cls).generate_config(args, config_dir_path)
+        base_key_name = os.path.join(config_dir_path, args.server_name)
+
+        args.pid_file = os.path.abspath(args.pid_file)
+
+        if not args.signing_key_path:
+            args.signing_key_path = base_key_name + ".signing.key"
+
+        if not os.path.exists(args.signing_key_path):
+            with open(args.signing_key_path, "w") as signing_key_file:
+                syutil.crypto.signing_key.write_signing_keys(
+                    signing_key_file,
+                    (syutil.crypto.signing_key.generate_signing_key("auto"),),
+                )
+        else:
+            signing_keys = cls.read_file(args.signing_key_path, "signing_key")
+            if len(signing_keys.split("\n")[0].split()) == 1:
+                # handle keys in the old format.
+                key = syutil.crypto.signing_key.decode_signing_key_base64(
+                    syutil.crypto.signing_key.NACL_ED25519,
+                    "auto",
+                    signing_keys.split("\n")[0]
+                )
+                with open(args.signing_key_path, "w") as signing_key_file:
+                    syutil.crypto.signing_key.write_signing_keys(
+                        signing_key_file,
+                        (key,),
+                    )
+
+        if not args.old_signing_key_path:
+            args.old_signing_key_path = base_key_name + ".old.signing.keys"
+
+        if not os.path.exists(args.old_signing_key_path):
+            with open(args.old_signing_key_path, "w"):
+                pass
+
+        if not args.perspectives_config_path:
+            args.perspectives_config_path = base_key_name + ".perspectives"
+
+        if not os.path.exists(args.perspectives_config_path):
+            with open(args.perspectives_config_path, "w") as perspectives_file:
+                perspectives_file.write(
+                    'servers:\n'
+                    '  matrix.org:\n'
+                    '    verify_keys:\n'
+                    '      "ed25519:auto":\n'
+                    '         key: "Noi6WqcDj0QmPxCNQqgezwTlBKrfqehY1u2FyWP9uYw"\n'
+                )

synapse/config/server.py

@@ -13,16 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import os
-from ._base import Config, ConfigError
-import syutil.crypto.signing_key
+from ._base import Config
 
 
 class ServerConfig(Config):
     def __init__(self, args):
         super(ServerConfig, self).__init__(args)
         self.server_name = args.server_name
-        self.signing_key = self.read_signing_key(args.signing_key_path)
         self.bind_port = args.bind_port
         self.bind_host = args.bind_host
         self.unsecure_port = args.unsecure_port
@@ -53,8 +50,6 @@ def add_arguments(cls, parser):
                  "This is used by remote servers to connect to this server, "
                  "e.g. matrix.org, localhost:8080, etc."
         )
-        server_group.add_argument("--signing-key-path",
-                                  help="The signing key to sign messages with")
         server_group.add_argument("-p", "--bind-port", metavar="PORT",
                                   type=int, help="https port to listen on",
                                   default=8448)
@@ -83,46 +78,3 @@ def add_arguments(cls, parser):
                                        "Zero is used to indicate synapse "
                                        "should set the soft limit to the hard"
                                        "limit.")
-
-    def read_signing_key(self, signing_key_path):
-        signing_keys = self.read_file(signing_key_path, "signing_key")
-        try:
-            return syutil.crypto.signing_key.read_signing_keys(
-                signing_keys.splitlines(True)
-            )
-        except Exception:
-            raise ConfigError(
-                "Error reading signing_key."
-                " Try running again with --generate-config"
-            )
-
-    @classmethod
-    def generate_config(cls, args, config_dir_path):
-        super(ServerConfig, cls).generate_config(args, config_dir_path)
-        base_key_name = os.path.join(config_dir_path, args.server_name)
-
-        args.pid_file = os.path.abspath(args.pid_file)
-
-        if not args.signing_key_path:
-            args.signing_key_path = base_key_name + ".signing.key"
-
-        if not os.path.exists(args.signing_key_path):
-            with open(args.signing_key_path, "w") as signing_key_file:
-                syutil.crypto.signing_key.write_signing_keys(
-                    signing_key_file,
-                    (syutil.crypto.signing_key.generate_signing_key("auto"),),
-                )
-        else:
-            signing_keys = cls.read_file(args.signing_key_path, "signing_key")
-            if len(signing_keys.split("\n")[0].split()) == 1:
-                # handle keys in the old format.
-                key = syutil.crypto.signing_key.decode_signing_key_base64(
-                    syutil.crypto.signing_key.NACL_ED25519,
-                    "auto",
-                    signing_keys.split("\n")[0]
-                )
-                with open(args.signing_key_path, "w") as signing_key_file:
-                    syutil.crypto.signing_key.write_signing_keys(
-                        signing_key_file,
-                        (key,),
-                    )

synapse/crypto/keyclient.py

@@ -25,12 +25,15 @@
 
 logger = logging.getLogger(__name__)
 
+KEY_API_V1 = b"/_matrix/key/v1/"
+
 
 @defer.inlineCallbacks
-def fetch_server_key(server_name, ssl_context_factory):
+def fetch_server_key(server_name, ssl_context_factory, path=KEY_API_V1):
     """Fetch the keys for a remote server."""
 
     factory = SynapseKeyClientFactory()
+    factory.path = path
     endpoint = matrix_federation_endpoint(
         reactor, server_name, ssl_context_factory, timeout=30
     )
@@ -42,13 +45,19 @@ def fetch_server_key(server_name, ssl_context_factory):
                 server_response, server_certificate = yield protocol.remote_key
                 defer.returnValue((server_response, server_certificate))
                 return
+        except SynapseKeyClientError as e:
+            logger.exception("Error getting key for %r" % (server_name,))
+            if e.status.startswith("4"):
+                # Don't retry for 4xx responses.
+                raise IOError("Cannot get key for %r" % server_name)
         except Exception as e:
             logger.exception(e)
-    raise IOError("Cannot get key for %s" % server_name)
+    raise IOError("Cannot get key for %r" % server_name)
 
 
 class SynapseKeyClientError(Exception):
     """The key wasn't retrieved from the remote server."""
+    status = None
     pass
 
 
@@ -66,17 +75,30 @@ def __init__(self):
     def connectionMade(self):
         self.host = self.transport.getHost()
         logger.debug("Connected to %s", self.host)
-        self.sendCommand(b"GET", b"/_matrix/key/v1/")
+        self.sendCommand(b"GET", self.path)
         self.endHeaders()
         self.timer = reactor.callLater(
             self.timeout,
             self.on_timeout
         )
 
+    def errback(self, error):
+        if not self.remote_key.called:
+            self.remote_key.errback(error)
+
+    def callback(self, result):
+        if not self.remote_key.called:
+            self.remote_key.callback(result)
+
     def handleStatus(self, version, status, message):
         if status != b"200":
             # logger.info("Non-200 response from %s: %s %s",
             #            self.transport.getHost(), status, message)
+            error = SynapseKeyClientError(
+                "Non-200 response %r from %r" % (status, self.host)
+            )
+            error.status = status
+            self.errback(error)
             self.transport.abortConnection()
 
     def handleResponse(self, response_body_bytes):
@@ -89,15 +111,18 @@ def handleResponse(self, response_body_bytes):
             return
 
         certificate = self.transport.getPeerCertificate()
-        self.remote_key.callback((json_response, certificate))
+        self.callback((json_response, certificate))
         self.transport.abortConnection()
         self.timer.cancel()
 
     def on_timeout(self):
         logger.debug("Timeout waiting for response from %s", self.host)
-        self.remote_key.errback(IOError("Timeout waiting for response"))
+        self.errback(IOError("Timeout waiting for response"))
         self.transport.abortConnection()
 
 
 class SynapseKeyClientFactory(Factory):
-    protocol = SynapseKeyClientProtocol
+    def protocol(self):
+        protocol = SynapseKeyClientProtocol()
+        protocol.path = self.path
+        return protocol