mitmproxy/libmproxy/protocol2/http.py
2015-08-14 10:41:11 +02:00

217 lines
8.2 KiB
Python

from __future__ import (absolute_import, print_function, division)
from .. import version
from ..exceptions import InvalidCredentials, HttpException, ProtocolException
from .layer import Layer, ServerConnectionMixin
from .messages import ChangeServer, Connect, Reconnect
from .http_proxy import HttpProxy, HttpUpstreamProxy
from libmproxy.protocol import KILL
from libmproxy.protocol.http import HTTPFlow
from libmproxy.protocol.http_wrappers import HTTPResponse, HTTPRequest
from libmproxy.protocol2.http_protocol_mock import HTTP1
from libmproxy.protocol2.tls import TlsLayer
from netlib import tcp
from netlib.http import status_codes
from netlib import odict
def make_error_response(status_code, message, headers=None):
response = status_codes.RESPONSES.get(status_code, "Unknown")
body = """
<html>
<head>
<title>%d %s</title>
</head>
<body>%s</body>
</html>
""".strip() % (status_code, response, message)
if not headers:
headers = odict.ODictCaseless()
headers["Server"] = [version.NAMEVERSION]
headers["Connection"] = ["close"]
headers["Content-Length"] = [len(body)]
headers["Content-Type"] = ["text/html"]
return HTTPResponse(
(1, 1), # FIXME: Should be a string.
status_code,
response,
headers,
body,
)
def make_connect_request(address):
return HTTPRequest(
"authority", "CONNECT", None, address.host, address.port, None, (1,1),
odict.ODictCaseless(), ""
)
def make_connect_response(httpversion):
headers = odict.ODictCaseless([
["Content-Length", "0"],
["Proxy-Agent", version.NAMEVERSION]
])
return HTTPResponse(
httpversion,
200,
"Connection established",
headers,
"",
)
class HttpLayer(Layer, ServerConnectionMixin):
"""
HTTP 1 Layer
"""
def __init__(self, ctx):
super(HttpLayer, self).__init__(ctx)
if any(isinstance(l, HttpProxy) for l in self.layers):
self.mode = "regular"
elif any(isinstance(l, HttpUpstreamProxy) for l in self.layers):
self.mode = "upstream"
else:
# also includes socks or reverse mode, which are handled similarly on this layer.
self.mode = "transparent"
def __call__(self):
while True:
try:
request = HTTP1.read_request(
self.client_conn,
body_size_limit=self.c.config.body_size_limit
)
except tcp.NetLibError:
# don't throw an error for disconnects that happen
# before/between requests.
return
self.c.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.server_address = (request.host, request.port)
self.send_to_client(make_connect_response(request.httpversion))
layer = self.ctx.next_layer(self)
for message in layer():
if not self._handle_server_message(message):
yield message
return
# Make sure that the incoming request matches our expectations
self.validate_request(request)
flow = HTTPFlow(self.client_conn, self.server_conn)
flow.request = request
if not self.process_request_hook(flow):
self.log("Connection killed", "info")
return
if not flow.response:
self.establish_server_connection(flow)
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.ctx.server_address.host
flow.request.port = self.ctx.server_address.port
flow.request.scheme = self.server_conn.tls_established
# TODO: Expose ChangeServer functionality to inline scripts somehow? (yield_from_callback?)
request_reply = self.c.channel.ask("request", flow)
if request_reply is None or request_reply == KILL:
return False
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 self.server_address != address or tls != self.server_address.ssl_established:
yield ChangeServer(address, tls, address.host)
# Establish connection is neccessary.
if not self.server_conn:
yield Connect()
# ChangeServer 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 tls:
raise HttpException("Cannot change scheme in upstream proxy mode.")
"""
# This is a very ugly (untested) workaround to solve a very ugly problem.
# FIXME: Check if connected first.
if self.server_conn.tls_established and not ssl:
yield Reconnect()
elif ssl and not hasattr(self, "connected_to") or self.connected_to != address:
if self.server_conn.tls_established:
yield Reconnect()
self.send_to_server(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_resplonse(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": ("regular",)
}
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_to_client(make_error_response(400, err_message))
raise HttpException(err_message)
def authenticate(self, request):
if self.config.authenticator:
if self.config.authenticator.authenticate(request.headers):
self.config.authenticator.clean(request.headers)
else:
self.send_to_client(make_error_response(
407,
"Proxy Authentication Required",
self.config.authenticator.auth_challenge_headers()
))
raise InvalidCredentials("Proxy Authentication Required")
def send_to_server(self, message):
self.server_conn.wfile.wrie(message)
def send_to_client(self, message):
# FIXME
# - possibly do some http2 stuff here
# - fix message assembly.
self.client_conn.wfile.write(message)