mitmproxy/libmproxy/protocol/http.py
2015-08-31 17:05:52 +02:00

538 lines
20 KiB
Python

from __future__ import (absolute_import, print_function, division)
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 .. 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 _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" # pragma: no cover
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)
def connect(self):
self.ctx.connect()
self.server_protocol = HTTP1Protocol(self.server_conn)
def reconnect(self):
self.ctx.reconnect()
self.server_protocol = HTTP1Protocol(self.server_conn)
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, address, ctx):
self.address = tcp.Address.wrap(address)
self._ctx = ctx
@property
def via(self):
return self._ctx.server_conn
def __getattr__(self, item):
return getattr(self.via, item)
def __nonzero__(self):
return bool(self.via)
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 _send_connect_request(self):
self.send_request(self.connect_request)
resp = self.read_response("CONNECT")
if resp.code != 200:
raise ProtocolException("Reconnect: Upstream server refuses CONNECT request")
def connect(self):
if not self.server_conn:
self.ctx.connect()
self._send_connect_request()
else:
pass # swallow the message
def reconnect(self):
self.ctx.reconnect()
self._send_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):
"""
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(flow.request.method)
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 == 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 == 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 == 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()
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")