diff options
Diffstat (limited to 'libmproxy/protocol/http.py')
| -rw-r--r-- | libmproxy/protocol/http.py | 602 |
1 files changed, 524 insertions, 78 deletions
diff --git a/libmproxy/protocol/http.py b/libmproxy/protocol/http.py index bde7b088..fc57f6df 100644 --- a/libmproxy/protocol/http.py +++ b/libmproxy/protocol/http.py @@ -1,92 +1,538 @@ -from __future__ import absolute_import +from __future__ import (absolute_import, print_function, division) -from .primitives import Flow +from netlib import tcp +from netlib.http import http1, HttpErrorConnClosed, HttpError +from netlib.http.semantics import CONTENT_MISSING +from netlib import odict +from netlib.tcp import NetLibError, Address +from netlib.http.http1 import HTTP1Protocol +from netlib.http.http2 import HTTP2Protocol -from .http_wrappers import decoded, HTTPRequest, HTTPResponse +from .. import utils +from ..exceptions import InvalidCredentials, HttpException, ProtocolException +from ..models import ( + HTTPFlow, HTTPRequest, HTTPResponse, make_error_response, make_connect_response, Error +) +from .base import Layer, Kill -class HTTPFlow(Flow): - """ - A HTTPFlow is a collection of objects representing a single HTTP - transaction. The main attributes are: - request: HTTPRequest object - response: HTTPResponse object - error: Error object - server_conn: ServerConnection object - client_conn: ClientConnection object +class _HttpLayer(Layer): + supports_streaming = False + + def read_request(self): + raise NotImplementedError() + + def send_request(self, request): + raise NotImplementedError() + + def read_response(self, request_method): + raise NotImplementedError() + + def send_response(self, response): + raise NotImplementedError() + + +class _StreamingHttpLayer(_HttpLayer): + supports_streaming = True + + def read_response_headers(self): + raise NotImplementedError + + def read_response_body(self, headers, request_method, response_code, max_chunk_size=None): + raise NotImplementedError() + yield "this is a generator" + + def send_response_headers(self, response): + raise NotImplementedError + + def send_response_body(self, response, chunks): + raise NotImplementedError() + + +class Http1Layer(_StreamingHttpLayer): + def __init__(self, ctx, mode): + super(Http1Layer, self).__init__(ctx) + self.mode = mode + self.client_protocol = HTTP1Protocol(self.client_conn) + self.server_protocol = HTTP1Protocol(self.server_conn) + + def read_request(self): + return HTTPRequest.from_protocol( + self.client_protocol, + body_size_limit=self.config.body_size_limit + ) + + def send_request(self, request): + self.server_conn.send(self.server_protocol.assemble(request)) + + def read_response(self, request_method): + return HTTPResponse.from_protocol( + self.server_protocol, + request_method=request_method, + body_size_limit=self.config.body_size_limit, + include_body=True + ) + + def send_response(self, response): + self.client_conn.send(self.client_protocol.assemble(response)) + + def read_response_headers(self): + return HTTPResponse.from_protocol( + self.server_protocol, + request_method=None, # does not matter if we don't read the body. + body_size_limit=self.config.body_size_limit, + include_body=False + ) + + def read_response_body(self, headers, request_method, response_code, max_chunk_size=None): + return self.server_protocol.read_http_body_chunked( + headers, + self.config.body_size_limit, + request_method, + response_code, + False, + max_chunk_size + ) + + def send_response_headers(self, response): + h = self.client_protocol._assemble_response_first_line(response) + self.client_conn.wfile.write(h + "\r\n") + h = self.client_protocol._assemble_response_headers( + response, + preserve_transfer_encoding=True + ) + self.client_conn.send(h + "\r\n") + + def send_response_body(self, response, chunks): + if self.client_protocol.has_chunked_encoding(response.headers): + chunks = ( + "%d\r\n%s\r\n" % (len(chunk), chunk) + for chunk in chunks + ) + for chunk in chunks: + self.client_conn.send(chunk) - Note that it's possible for a Flow to have both a response and an error - object. This might happen, for instance, when a response was received - from the server, but there was an error sending it back to the client. + def connect(self): + self.ctx.connect() + self.server_protocol = HTTP1Protocol(self.server_conn) - The following additional attributes are exposed: + def reconnect(self): + self.ctx.reconnect() + self.server_protocol = HTTP1Protocol(self.server_conn) - intercepted: Is this flow currently being intercepted? - live: Does this flow have a live client connection? + def set_server(self, *args, **kwargs): + self.ctx.set_server(*args, **kwargs) + self.server_protocol = HTTP1Protocol(self.server_conn) + + def __call__(self): + layer = HttpLayer(self, self.mode) + layer() + + +# TODO: The HTTP2 layer is missing multiplexing, which requires a major rewrite. +class Http2Layer(_HttpLayer): + def __init__(self, ctx, mode): + super(Http2Layer, self).__init__(ctx) + self.mode = mode + self.client_protocol = HTTP2Protocol(self.client_conn, is_server=True, + unhandled_frame_cb=self.handle_unexpected_frame) + self.server_protocol = HTTP2Protocol(self.server_conn, is_server=False, + unhandled_frame_cb=self.handle_unexpected_frame) + + def read_request(self): + request = HTTPRequest.from_protocol( + self.client_protocol, + body_size_limit=self.config.body_size_limit + ) + self._stream_id = request.stream_id + return request + + def send_request(self, message): + # TODO: implement flow control and WINDOW_UPDATE frames + self.server_conn.send(self.server_protocol.assemble(message)) + + def read_response(self, request_method): + return HTTPResponse.from_protocol( + self.server_protocol, + request_method=request_method, + body_size_limit=self.config.body_size_limit, + include_body=True, + stream_id=self._stream_id + ) + + def send_response(self, message): + # TODO: implement flow control and WINDOW_UPDATE frames + self.client_conn.send(self.client_protocol.assemble(message)) + + def connect(self): + self.ctx.connect() + self.server_protocol = HTTP2Protocol(self.server_conn, is_server=False, + unhandled_frame_cb=self.handle_unexpected_frame) + self.server_protocol.perform_connection_preface() + + def reconnect(self): + self.ctx.reconnect() + self.server_protocol = HTTP2Protocol(self.server_conn, is_server=False, + unhandled_frame_cb=self.handle_unexpected_frame) + self.server_protocol.perform_connection_preface() + + def set_server(self, *args, **kwargs): + self.ctx.set_server(*args, **kwargs) + self.server_protocol = HTTP2Protocol(self.server_conn, is_server=False, + unhandled_frame_cb=self.handle_unexpected_frame) + self.server_protocol.perform_connection_preface() + + def __call__(self): + self.server_protocol.perform_connection_preface() + layer = HttpLayer(self, self.mode) + layer() + + def handle_unexpected_frame(self, frm): + self.log("Unexpected HTTP2 Frame: %s" % frm.human_readable(), "info") + + +class ConnectServerConnection(object): + """ + "Fake" ServerConnection to represent state after a CONNECT request to an upstream proxy. """ - def __init__(self, client_conn, server_conn, live=None): - super(HTTPFlow, self).__init__("http", client_conn, server_conn, live) - self.request = None - """@type: HTTPRequest""" - self.response = None - """@type: HTTPResponse""" - - _stateobject_attributes = Flow._stateobject_attributes.copy() - _stateobject_attributes.update( - request=HTTPRequest, - response=HTTPResponse - ) - - @classmethod - def from_state(cls, state): - f = cls(None, None) - f.load_state(state) - return f - - def __repr__(self): - s = "<HTTPFlow" - for a in ("request", "response", "error", "client_conn", "server_conn"): - if getattr(self, a, False): - s += "\r\n %s = {flow.%s}" % (a, a) - s += ">" - return s.format(flow=self) - - def copy(self): - f = super(HTTPFlow, self).copy() - if self.request: - f.request = self.request.copy() - if self.response: - f.response = self.response.copy() - return f - - def match(self, f): - """ - Match this flow against a compiled filter expression. Returns True - if matched, False if not. + def __init__(self, address, ctx): + self.address = tcp.Address.wrap(address) + self._ctx = ctx - If f is a string, it will be compiled as a filter expression. If - the expression is invalid, ValueError is raised. - """ - if isinstance(f, basestring): - from .. import filt + @property + def via(self): + return self._ctx.server_conn - f = filt.parse(f) - if not f: - raise ValueError("Invalid filter expression.") - if f: - return f(self) - return True + def __getattr__(self, item): + return getattr(self.via, item) - def replace(self, pattern, repl, *args, **kwargs): - """ - Replaces a regular expression pattern with repl in both request and - response of the flow. Encoded content will be decoded before - replacement, and re-encoded afterwards. - Returns the number of replacements made. +class UpstreamConnectLayer(Layer): + def __init__(self, ctx, connect_request): + super(UpstreamConnectLayer, self).__init__(ctx) + self.connect_request = connect_request + self.server_conn = ConnectServerConnection( + (connect_request.host, connect_request.port), + self.ctx + ) + + def __call__(self): + layer = self.ctx.next_layer(self) + layer() + + def connect(self): + if not self.server_conn: + self.ctx.connect() + self.send_request(self.connect_request) + else: + pass # swallow the message + + def reconnect(self): + self.ctx.reconnect() + self.send_request(self.connect_request) + resp = self.read_response("CONNECT") + if resp.code != 200: + raise ProtocolException("Reconnect: Upstream server refuses CONNECT request") + + def set_server(self, address, server_tls=None, sni=None, depth=1): + if depth == 1: + if self.ctx.server_conn: + self.ctx.reconnect() + address = Address.wrap(address) + self.connect_request.host = address.host + self.connect_request.port = address.port + self.server_conn.address = address + else: + self.ctx.set_server(address, server_tls, sni, depth - 1) + + +class HttpLayer(Layer): + def __init__(self, ctx, mode): + super(HttpLayer, self).__init__(ctx) + self.mode = mode + self.__original_server_conn = None + "Contains the original destination in transparent mode, which needs to be restored" + "if an inline script modified the target server for a single http request" + + def __call__(self): + if self.mode == "transparent": + self.__original_server_conn = self.server_conn + while True: + try: + flow = HTTPFlow(self.client_conn, self.server_conn, live=self) + + try: + request = self.read_request() + except tcp.NetLibError: + # don't throw an error for disconnects that happen + # before/between requests. + return + + self.log("request", "debug", [repr(request)]) + + # Handle Proxy Authentication + self.authenticate(request) + + # Regular Proxy Mode: Handle CONNECT + if self.mode == "regular" and request.form_in == "authority": + self.handle_regular_mode_connect(request) + return + + # Make sure that the incoming request matches our expectations + self.validate_request(request) + + flow.request = request + self.process_request_hook(flow) + + if not flow.response: + self.establish_server_connection(flow) + self.get_response_from_server(flow) + + self.send_response_to_client(flow) + + if self.check_close_connection(flow): + return + + # TODO: Implement HTTP Upgrade + + # Upstream Proxy Mode: Handle CONNECT + if flow.request.form_in == "authority" and flow.response.code == 200: + self.handle_upstream_mode_connect(flow.request.copy()) + return + + except (HttpErrorConnClosed, NetLibError, HttpError, ProtocolException) as e: + if flow.request and not flow.response: + flow.error = Error(repr(e)) + self.channel.ask("error", flow) + try: + self.send_response(make_error_response( + getattr(e, "code", 502), + repr(e) + )) + except NetLibError: + pass + if isinstance(e, ProtocolException): + raise e + else: + raise ProtocolException("Error in HTTP connection: %s" % repr(e), e) + finally: + flow.live = False + + def handle_regular_mode_connect(self, request): + self.set_server((request.host, request.port)) + self.send_response(make_connect_response(request.httpversion)) + layer = self.ctx.next_layer(self) + layer() + + def handle_upstream_mode_connect(self, connect_request): + layer = UpstreamConnectLayer(self, connect_request) + layer() + + def check_close_connection(self, flow): """ - c = self.request.replace(pattern, repl, *args, **kwargs) - if self.response: - c += self.response.replace(pattern, repl, *args, **kwargs) - return c + Checks if the connection should be closed depending on the HTTP + semantics. Returns True, if so. + """ + + # TODO: add logic for HTTP/2 + + close_connection = ( + http1.HTTP1Protocol.connection_close( + flow.request.httpversion, + flow.request.headers + ) or http1.HTTP1Protocol.connection_close( + flow.response.httpversion, + flow.response.headers + ) or http1.HTTP1Protocol.expected_http_body_size( + flow.response.headers, + False, + flow.request.method, + flow.response.code) == -1 + ) + if flow.request.form_in == "authority" and flow.response.code == 200: + # Workaround for + # https://github.com/mitmproxy/mitmproxy/issues/313: Some + # proxies (e.g. Charles) send a CONNECT response with HTTP/1.0 + # and no Content-Length header + + return False + return close_connection + + def send_response_to_client(self, flow): + if not (self.supports_streaming and flow.response.stream): + # no streaming: + # we already received the full response from the server and can + # send it to the client straight away. + self.send_response(flow.response) + else: + # streaming: + # First send the headers and then transfer the response incrementally + self.send_response_headers(flow.response) + chunks = self.read_response_body( + flow.response.headers, + flow.request.method, + flow.response.code, + max_chunk_size=4096 + ) + if callable(flow.response.stream): + chunks = flow.response.stream(chunks) + self.send_response_body(flow.response, chunks) + flow.response.timestamp_end = utils.timestamp() + + def get_response_from_server(self, flow): + def get_response(): + self.send_request(flow.request) + if self.supports_streaming: + flow.response = self.read_response_headers() + else: + flow.response = self.read_response() + + try: + get_response() + except (tcp.NetLibError, HttpErrorConnClosed) as v: + self.log( + "server communication error: %s" % repr(v), + level="debug" + ) + # In any case, we try to reconnect at least once. This is + # necessary because it might be possible that we already + # initiated an upstream connection after clientconnect that + # has already been expired, e.g consider the following event + # log: + # > clientconnect (transparent mode destination known) + # > serverconnect (required for client tls handshake) + # > read n% of large request + # > server detects timeout, disconnects + # > read (100-n)% of large request + # > send large request upstream + self.reconnect() + get_response() + + # call the appropriate script hook - this is an opportunity for an + # inline script to set flow.stream = True + flow = self.channel.ask("responseheaders", flow) + if flow is None or flow == Kill: + raise Kill() + + if self.supports_streaming: + if flow.response.stream: + flow.response.content = CONTENT_MISSING + else: + flow.response.content = "".join(self.read_response_body( + flow.response.headers, + flow.request.method, + flow.response.code + )) + flow.response.timestamp_end = utils.timestamp() + + # no further manipulation of self.server_conn beyond this point + # we can safely set it as the final attribute value here. + flow.server_conn = self.server_conn + + self.log( + "response", + "debug", + [repr(flow.response)] + ) + response_reply = self.channel.ask("response", flow) + if response_reply is None or response_reply == Kill: + raise Kill() + + def process_request_hook(self, flow): + # Determine .scheme, .host and .port attributes for inline scripts. + # For absolute-form requests, they are directly given in the request. + # For authority-form requests, we only need to determine the request scheme. + # For relative-form requests, we need to determine host and port as + # well. + if self.mode == "regular": + pass # only absolute-form at this point, nothing to do here. + elif self.mode == "upstream": + if flow.request.form_in == "authority": + flow.request.scheme = "http" # pseudo value + else: + flow.request.host = self.__original_server_conn.address.host + flow.request.port = self.__original_server_conn.address.port + flow.request.scheme = "https" if self.__original_server_conn.tls_established else "http" + + request_reply = self.channel.ask("request", flow) + if request_reply is None or request_reply == Kill: + raise Kill() + if isinstance(request_reply, HTTPResponse): + flow.response = request_reply + return + + def establish_server_connection(self, flow): + address = tcp.Address((flow.request.host, flow.request.port)) + tls = (flow.request.scheme == "https") + + if self.mode == "regular" or self.mode == "transparent": + # If there's an existing connection that doesn't match our expectations, kill it. + if address != self.server_conn.address or tls != self.server_conn.ssl_established: + self.set_server(address, tls, address.host) + # Establish connection is neccessary. + if not self.server_conn: + self.connect() + + # SetServer is not guaranteed to work with TLS: + # If there's not TlsLayer below which could catch the exception, + # TLS will not be established. + if tls and not self.server_conn.tls_established: + raise ProtocolException( + "Cannot upgrade to SSL, no TLS layer on the protocol stack.") + else: + if not self.server_conn: + self.connect() + if tls: + raise HttpException("Cannot change scheme in upstream proxy mode.") + """ + # This is a very ugly (untested) workaround to solve a very ugly problem. + if self.server_conn and self.server_conn.tls_established and not ssl: + self.reconnect() + elif ssl and not hasattr(self, "connected_to") or self.connected_to != address: + if self.server_conn.tls_established: + self.reconnect() + + self.send_request(make_connect_request(address)) + tls_layer = TlsLayer(self, False, True) + tls_layer._establish_tls_with_server() + """ + + def validate_request(self, request): + if request.form_in == "absolute" and request.scheme != "http": + self.send_response( + make_error_response(400, "Invalid request scheme: %s" % request.scheme)) + raise HttpException("Invalid request scheme: %s" % request.scheme) + + expected_request_forms = { + "regular": ("absolute",), # an authority request would already be handled. + "upstream": ("authority", "absolute"), + "transparent": ("relative",) + } + + allowed_request_forms = expected_request_forms[self.mode] + if request.form_in not in allowed_request_forms: + err_message = "Invalid HTTP request form (expected: %s, got: %s)" % ( + " or ".join(allowed_request_forms), request.form_in + ) + self.send_response(make_error_response(400, err_message)) + raise HttpException(err_message) + + if self.mode == "regular": + request.form_out = "relative" + + def authenticate(self, request): + if self.config.authenticator: + if self.config.authenticator.authenticate(request.headers): + self.config.authenticator.clean(request.headers) + else: + self.send_response(make_error_response( + 407, + "Proxy Authentication Required", + odict.ODictCaseless( + [ + [k, v] for k, v in + self.config.authenticator.auth_challenge_headers().items() + ]) + )) + raise InvalidCredentials("Proxy Authentication Required") |