138 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			138 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			Python
		
	
	
# -*- coding: utf-8 -*-
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# Copyright 2014-2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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#     http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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from canonicaljson import json
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from twisted.internet import defer, reactor
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from twisted.internet.protocol import Factory
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from twisted.web.http import HTTPClient
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from synapse.http.endpoint import matrix_federation_endpoint
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from synapse.util import logcontext
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logger = logging.getLogger(__name__)
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KEY_API_V1 = b"/_matrix/key/v1/"
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@defer.inlineCallbacks
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def fetch_server_key(server_name, ssl_context_factory, path=KEY_API_V1):
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    """Fetch the keys for a remote server."""
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    factory = SynapseKeyClientFactory()
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    factory.path = path
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    factory.host = server_name
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    endpoint = matrix_federation_endpoint(
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        reactor, server_name, ssl_context_factory, timeout=30
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    )
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    for i in range(5):
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        try:
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            with logcontext.PreserveLoggingContext():
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                protocol = yield endpoint.connect(factory)
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                server_response, server_certificate = yield protocol.remote_key
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                defer.returnValue((server_response, server_certificate))
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        except SynapseKeyClientError as e:
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            logger.exception("Error getting key for %r" % (server_name,))
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            if e.status.startswith("4"):
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                # Don't retry for 4xx responses.
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                raise IOError("Cannot get key for %r" % server_name)
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        except Exception as e:
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            logger.exception(e)
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    raise IOError("Cannot get key for %r" % server_name)
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class SynapseKeyClientError(Exception):
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    """The key wasn't retrieved from the remote server."""
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    status = None
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    pass
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class SynapseKeyClientProtocol(HTTPClient):
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    """Low level HTTPS client which retrieves an application/json response from
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    the server and extracts the X.509 certificate for the remote peer from the
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    SSL connection."""
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    timeout = 30
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    def __init__(self):
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        self.remote_key = defer.Deferred()
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        self.host = None
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        self._peer = None
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    def connectionMade(self):
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        self._peer = self.transport.getPeer()
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        logger.debug("Connected to %s", self._peer)
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        self.sendCommand(b"GET", self.path)
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        if self.host:
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            self.sendHeader(b"Host", self.host)
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        self.endHeaders()
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        self.timer = reactor.callLater(
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            self.timeout,
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            self.on_timeout
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        )
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    def errback(self, error):
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        if not self.remote_key.called:
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            self.remote_key.errback(error)
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    def callback(self, result):
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        if not self.remote_key.called:
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            self.remote_key.callback(result)
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    def handleStatus(self, version, status, message):
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        if status != b"200":
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            # logger.info("Non-200 response from %s: %s %s",
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            #            self.transport.getHost(), status, message)
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            error = SynapseKeyClientError(
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                "Non-200 response %r from %r" % (status, self.host)
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            )
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            error.status = status
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            self.errback(error)
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            self.transport.abortConnection()
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    def handleResponse(self, response_body_bytes):
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        try:
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            json_response = json.loads(response_body_bytes)
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        except ValueError:
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            # logger.info("Invalid JSON response from %s",
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            #            self.transport.getHost())
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            self.transport.abortConnection()
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            return
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        certificate = self.transport.getPeerCertificate()
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        self.callback((json_response, certificate))
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        self.transport.abortConnection()
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        self.timer.cancel()
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    def on_timeout(self):
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        logger.debug(
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            "Timeout waiting for response from %s: %s",
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            self.host, self._peer,
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        )
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        self.errback(IOError("Timeout waiting for response"))
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        self.transport.abortConnection()
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class SynapseKeyClientFactory(Factory):
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    def protocol(self):
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        protocol = SynapseKeyClientProtocol()
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        protocol.path = self.path
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        protocol.host = self.host
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        return protocol
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