From 1cb84c6486a5131dd284f341bb657434becda255 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Fri, 1 Nov 2019 14:07:44 +0000 Subject: Support for routing outbound HTTP requests via a proxy (#6239) The `http_proxy` and `HTTPS_PROXY` env vars can be set to a `host[:port]` value which should point to a proxy. The address of the proxy should be excluded from IP blacklists such as the `url_preview_ip_range_blacklist`. The proxy will then be used for * push * url previews * phone-home stats * recaptcha validation * CAS auth validation It will *not* be used for: * Application Services * Identity servers * Outbound federation * In worker configurations, connections from workers to masters Fixes #4198. --- synapse/http/client.py | 17 +++- synapse/http/connectproxyclient.py | 195 +++++++++++++++++++++++++++++++++++++ synapse/http/proxyagent.py | 195 +++++++++++++++++++++++++++++++++++++ 3 files changed, 405 insertions(+), 2 deletions(-) create mode 100644 synapse/http/connectproxyclient.py create mode 100644 synapse/http/proxyagent.py (limited to 'synapse/http') diff --git a/synapse/http/client.py b/synapse/http/client.py index 2df5b383b5..d4c285445e 100644 --- a/synapse/http/client.py +++ b/synapse/http/client.py @@ -45,6 +45,7 @@ from synapse.http import ( cancelled_to_request_timed_out_error, redact_uri, ) +from synapse.http.proxyagent import ProxyAgent from synapse.logging.context import make_deferred_yieldable from synapse.logging.opentracing import set_tag, start_active_span, tags from synapse.util.async_helpers import timeout_deferred @@ -183,7 +184,15 @@ class SimpleHttpClient(object): using HTTP in Matrix """ - def __init__(self, hs, treq_args={}, ip_whitelist=None, ip_blacklist=None): + def __init__( + self, + hs, + treq_args={}, + ip_whitelist=None, + ip_blacklist=None, + http_proxy=None, + https_proxy=None, + ): """ Args: hs (synapse.server.HomeServer) @@ -192,6 +201,8 @@ class SimpleHttpClient(object): we may not request. ip_whitelist (netaddr.IPSet): The whitelisted IP addresses, that we can request if it were otherwise caught in a blacklist. + http_proxy (bytes): proxy server to use for http connections. host[:port] + https_proxy (bytes): proxy server to use for https connections. host[:port] """ self.hs = hs @@ -236,11 +247,13 @@ class SimpleHttpClient(object): # The default context factory in Twisted 14.0.0 (which we require) is # BrowserLikePolicyForHTTPS which will do regular cert validation # 'like a browser' - self.agent = Agent( + self.agent = ProxyAgent( self.reactor, connectTimeout=15, contextFactory=self.hs.get_http_client_context_factory(), pool=pool, + http_proxy=http_proxy, + https_proxy=https_proxy, ) if self._ip_blacklist: diff --git a/synapse/http/connectproxyclient.py b/synapse/http/connectproxyclient.py new file mode 100644 index 0000000000..be7b2ceb8e --- /dev/null +++ b/synapse/http/connectproxyclient.py @@ -0,0 +1,195 @@ +# -*- coding: utf-8 -*- +# Copyright 2019 The Matrix.org Foundation C.I.C. +# +# 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 logging + +from zope.interface import implementer + +from twisted.internet import defer, protocol +from twisted.internet.error import ConnectError +from twisted.internet.interfaces import IStreamClientEndpoint +from twisted.internet.protocol import connectionDone +from twisted.web import http + +logger = logging.getLogger(__name__) + + +class ProxyConnectError(ConnectError): + pass + + +@implementer(IStreamClientEndpoint) +class HTTPConnectProxyEndpoint(object): + """An Endpoint implementation which will send a CONNECT request to an http proxy + + Wraps an existing HostnameEndpoint for the proxy. + + When we get the connect() request from the connection pool (via the TLS wrapper), + we'll first connect to the proxy endpoint with a ProtocolFactory which will make the + CONNECT request. Once that completes, we invoke the protocolFactory which was passed + in. + + Args: + reactor: the Twisted reactor to use for the connection + proxy_endpoint (IStreamClientEndpoint): the endpoint to use to connect to the + proxy + host (bytes): hostname that we want to CONNECT to + port (int): port that we want to connect to + """ + + def __init__(self, reactor, proxy_endpoint, host, port): + self._reactor = reactor + self._proxy_endpoint = proxy_endpoint + self._host = host + self._port = port + + def __repr__(self): + return "" % (self._proxy_endpoint,) + + def connect(self, protocolFactory): + f = HTTPProxiedClientFactory(self._host, self._port, protocolFactory) + d = self._proxy_endpoint.connect(f) + # once the tcp socket connects successfully, we need to wait for the + # CONNECT to complete. + d.addCallback(lambda conn: f.on_connection) + return d + + +class HTTPProxiedClientFactory(protocol.ClientFactory): + """ClientFactory wrapper that triggers an HTTP proxy CONNECT on connect. + + Once the CONNECT completes, invokes the original ClientFactory to build the + HTTP Protocol object and run the rest of the connection. + + Args: + dst_host (bytes): hostname that we want to CONNECT to + dst_port (int): port that we want to connect to + wrapped_factory (protocol.ClientFactory): The original Factory + """ + + def __init__(self, dst_host, dst_port, wrapped_factory): + self.dst_host = dst_host + self.dst_port = dst_port + self.wrapped_factory = wrapped_factory + self.on_connection = defer.Deferred() + + def startedConnecting(self, connector): + return self.wrapped_factory.startedConnecting(connector) + + def buildProtocol(self, addr): + wrapped_protocol = self.wrapped_factory.buildProtocol(addr) + + return HTTPConnectProtocol( + self.dst_host, self.dst_port, wrapped_protocol, self.on_connection + ) + + def clientConnectionFailed(self, connector, reason): + logger.debug("Connection to proxy failed: %s", reason) + if not self.on_connection.called: + self.on_connection.errback(reason) + return self.wrapped_factory.clientConnectionFailed(connector, reason) + + def clientConnectionLost(self, connector, reason): + logger.debug("Connection to proxy lost: %s", reason) + if not self.on_connection.called: + self.on_connection.errback(reason) + return self.wrapped_factory.clientConnectionLost(connector, reason) + + +class HTTPConnectProtocol(protocol.Protocol): + """Protocol that wraps an existing Protocol to do a CONNECT handshake at connect + + Args: + host (bytes): The original HTTP(s) hostname or IPv4 or IPv6 address literal + to put in the CONNECT request + + port (int): The original HTTP(s) port to put in the CONNECT request + + wrapped_protocol (interfaces.IProtocol): the original protocol (probably + HTTPChannel or TLSMemoryBIOProtocol, but could be anything really) + + connected_deferred (Deferred): a Deferred which will be callbacked with + wrapped_protocol when the CONNECT completes + """ + + def __init__(self, host, port, wrapped_protocol, connected_deferred): + self.host = host + self.port = port + self.wrapped_protocol = wrapped_protocol + self.connected_deferred = connected_deferred + self.http_setup_client = HTTPConnectSetupClient(self.host, self.port) + self.http_setup_client.on_connected.addCallback(self.proxyConnected) + + def connectionMade(self): + self.http_setup_client.makeConnection(self.transport) + + def connectionLost(self, reason=connectionDone): + if self.wrapped_protocol.connected: + self.wrapped_protocol.connectionLost(reason) + + self.http_setup_client.connectionLost(reason) + + if not self.connected_deferred.called: + self.connected_deferred.errback(reason) + + def proxyConnected(self, _): + self.wrapped_protocol.makeConnection(self.transport) + + self.connected_deferred.callback(self.wrapped_protocol) + + # Get any pending data from the http buf and forward it to the original protocol + buf = self.http_setup_client.clearLineBuffer() + if buf: + self.wrapped_protocol.dataReceived(buf) + + def dataReceived(self, data): + # if we've set up the HTTP protocol, we can send the data there + if self.wrapped_protocol.connected: + return self.wrapped_protocol.dataReceived(data) + + # otherwise, we must still be setting up the connection: send the data to the + # setup client + return self.http_setup_client.dataReceived(data) + + +class HTTPConnectSetupClient(http.HTTPClient): + """HTTPClient protocol to send a CONNECT message for proxies and read the response. + + Args: + host (bytes): The hostname to send in the CONNECT message + port (int): The port to send in the CONNECT message + """ + + def __init__(self, host, port): + self.host = host + self.port = port + self.on_connected = defer.Deferred() + + def connectionMade(self): + logger.debug("Connected to proxy, sending CONNECT") + self.sendCommand(b"CONNECT", b"%s:%d" % (self.host, self.port)) + self.endHeaders() + + def handleStatus(self, version, status, message): + logger.debug("Got Status: %s %s %s", status, message, version) + if status != b"200": + raise ProxyConnectError("Unexpected status on CONNECT: %s" % status) + + def handleEndHeaders(self): + logger.debug("End Headers") + self.on_connected.callback(None) + + def handleResponse(self, body): + pass diff --git a/synapse/http/proxyagent.py b/synapse/http/proxyagent.py new file mode 100644 index 0000000000..332da02a8d --- /dev/null +++ b/synapse/http/proxyagent.py @@ -0,0 +1,195 @@ +# -*- coding: utf-8 -*- +# Copyright 2019 The Matrix.org Foundation C.I.C. +# +# 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 logging +import re + +from zope.interface import implementer + +from twisted.internet import defer +from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS +from twisted.python.failure import Failure +from twisted.web.client import URI, BrowserLikePolicyForHTTPS, _AgentBase +from twisted.web.error import SchemeNotSupported +from twisted.web.iweb import IAgent + +from synapse.http.connectproxyclient import HTTPConnectProxyEndpoint + +logger = logging.getLogger(__name__) + +_VALID_URI = re.compile(br"\A[\x21-\x7e]+\Z") + + +@implementer(IAgent) +class ProxyAgent(_AgentBase): + """An Agent implementation which will use an HTTP proxy if one was requested + + Args: + reactor: twisted reactor to place outgoing + connections. + + contextFactory (IPolicyForHTTPS): A factory for TLS contexts, to control the + verification parameters of OpenSSL. The default is to use a + `BrowserLikePolicyForHTTPS`, so unless you have special + requirements you can leave this as-is. + + connectTimeout (float): The amount of time that this Agent will wait + for the peer to accept a connection. + + bindAddress (bytes): The local address for client sockets to bind to. + + pool (HTTPConnectionPool|None): connection pool to be used. If None, a + non-persistent pool instance will be created. + """ + + def __init__( + self, + reactor, + contextFactory=BrowserLikePolicyForHTTPS(), + connectTimeout=None, + bindAddress=None, + pool=None, + http_proxy=None, + https_proxy=None, + ): + _AgentBase.__init__(self, reactor, pool) + + self._endpoint_kwargs = {} + if connectTimeout is not None: + self._endpoint_kwargs["timeout"] = connectTimeout + if bindAddress is not None: + self._endpoint_kwargs["bindAddress"] = bindAddress + + self.http_proxy_endpoint = _http_proxy_endpoint( + http_proxy, reactor, **self._endpoint_kwargs + ) + + self.https_proxy_endpoint = _http_proxy_endpoint( + https_proxy, reactor, **self._endpoint_kwargs + ) + + self._policy_for_https = contextFactory + self._reactor = reactor + + def request(self, method, uri, headers=None, bodyProducer=None): + """ + Issue a request to the server indicated by the given uri. + + Supports `http` and `https` schemes. + + An existing connection from the connection pool may be used or a new one may be + created. + + See also: twisted.web.iweb.IAgent.request + + Args: + method (bytes): The request method to use, such as `GET`, `POST`, etc + + uri (bytes): The location of the resource to request. + + headers (Headers|None): Extra headers to send with the request + + bodyProducer (IBodyProducer|None): An object which can generate bytes to + make up the body of this request (for example, the properly encoded + contents of a file for a file upload). Or, None if the request is to + have no body. + + Returns: + Deferred[IResponse]: completes when the header of the response has + been received (regardless of the response status code). + """ + uri = uri.strip() + if not _VALID_URI.match(uri): + raise ValueError("Invalid URI {!r}".format(uri)) + + parsed_uri = URI.fromBytes(uri) + pool_key = (parsed_uri.scheme, parsed_uri.host, parsed_uri.port) + request_path = parsed_uri.originForm + + if parsed_uri.scheme == b"http" and self.http_proxy_endpoint: + # Cache *all* connections under the same key, since we are only + # connecting to a single destination, the proxy: + pool_key = ("http-proxy", self.http_proxy_endpoint) + endpoint = self.http_proxy_endpoint + request_path = uri + elif parsed_uri.scheme == b"https" and self.https_proxy_endpoint: + endpoint = HTTPConnectProxyEndpoint( + self._reactor, + self.https_proxy_endpoint, + parsed_uri.host, + parsed_uri.port, + ) + else: + # not using a proxy + endpoint = HostnameEndpoint( + self._reactor, parsed_uri.host, parsed_uri.port, **self._endpoint_kwargs + ) + + logger.debug("Requesting %s via %s", uri, endpoint) + + if parsed_uri.scheme == b"https": + tls_connection_creator = self._policy_for_https.creatorForNetloc( + parsed_uri.host, parsed_uri.port + ) + endpoint = wrapClientTLS(tls_connection_creator, endpoint) + elif parsed_uri.scheme == b"http": + pass + else: + return defer.fail( + Failure( + SchemeNotSupported("Unsupported scheme: %r" % (parsed_uri.scheme,)) + ) + ) + + return self._requestWithEndpoint( + pool_key, endpoint, method, parsed_uri, headers, bodyProducer, request_path + ) + + +def _http_proxy_endpoint(proxy, reactor, **kwargs): + """Parses an http proxy setting and returns an endpoint for the proxy + + Args: + proxy (bytes|None): the proxy setting + reactor: reactor to be used to connect to the proxy + kwargs: other args to be passed to HostnameEndpoint + + Returns: + interfaces.IStreamClientEndpoint|None: endpoint to use to connect to the proxy, + or None + """ + if proxy is None: + return None + + # currently we only support hostname:port. Some apps also support + # protocol://[:port], which allows a way of requiring a TLS connection to the + # proxy. + + host, port = parse_host_port(proxy, default_port=1080) + return HostnameEndpoint(reactor, host, port, **kwargs) + + +def parse_host_port(hostport, default_port=None): + # could have sworn we had one of these somewhere else... + if b":" in hostport: + host, port = hostport.rsplit(b":", 1) + try: + port = int(port) + return host, port + except ValueError: + # the thing after the : wasn't a valid port; presumably this is an + # IPv6 address. + pass + + return hostport, default_port -- cgit 1.4.1