mitmproxy/libmproxy/proxy.py

609 lines
22 KiB
Python

# Copyright (C) 2012 Aldo Cortesi
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
A simple proxy server implementation, which always reads all of a server
response into memory, performs some transformation, and then writes it back
to the client.
"""
import sys, os, string, socket, time
import shutil, tempfile, threading
import optparse, SocketServer
import utils, flow, certutils, version, wsgi, netlib
from OpenSSL import SSL
class ProxyError(Exception):
def __init__(self, code, msg):
self.code, self.msg = code, msg
def __str__(self):
return "ProxyError(%s, %s)"%(self.code, self.msg)
class ProxyConfig:
def __init__(self, certfile = None, cacert = None, clientcerts = None, cert_wait_time=0, upstream_cert=False, body_size_limit = None, reverse_proxy=None, transparent_proxy=None):
assert not (reverse_proxy and transparent_proxy)
self.certfile = certfile
self.cacert = cacert
self.clientcerts = clientcerts
self.certdir = None
self.cert_wait_time = cert_wait_time
self.upstream_cert = upstream_cert
self.body_size_limit = body_size_limit
self.reverse_proxy = reverse_proxy
self.transparent_proxy = transparent_proxy
def read_headers(fp):
"""
Read a set of headers from a file pointer. Stop once a blank line
is reached. Return a ODictCaseless object.
"""
ret = []
name = ''
while 1:
line = fp.readline()
if not line or line == '\r\n' or line == '\n':
break
if line[0] in ' \t':
# continued header
ret[-1][1] = ret[-1][1] + '\r\n ' + line.strip()
else:
i = line.find(':')
# We're being liberal in what we accept, here.
if i > 0:
name = line[:i]
value = line[i+1:].strip()
ret.append([name, value])
return flow.ODictCaseless(ret)
def read_chunked(fp, limit):
content = ""
total = 0
while 1:
line = fp.readline(128)
if line == "":
raise IOError("Connection closed")
if line == '\r\n' or line == '\n':
continue
try:
length = int(line,16)
except ValueError:
# FIXME: Not strictly correct - this could be from the server, in which
# case we should send a 502.
raise ProxyError(400, "Invalid chunked encoding length: %s"%line)
if not length:
break
total += length
if limit is not None and total > limit:
msg = "HTTP Body too large."\
" Limit is %s, chunked content length was at least %s"%(limit, total)
raise ProxyError(509, msg)
content += fp.read(length)
line = fp.readline(5)
if line != '\r\n':
raise IOError("Malformed chunked body")
while 1:
line = fp.readline()
if line == "":
raise IOError("Connection closed")
if line == '\r\n' or line == '\n':
break
return content
def has_chunked_encoding(headers):
for i in headers["transfer-encoding"]:
for j in i.split(","):
if j.lower() == "chunked":
return True
return False
def read_http_body(rfile, headers, all, limit):
if has_chunked_encoding(headers):
content = read_chunked(rfile, limit)
elif "content-length" in headers:
try:
l = int(headers["content-length"][0])
except ValueError:
# FIXME: Not strictly correct - this could be from the server, in which
# case we should send a 502.
raise ProxyError(400, "Invalid content-length header: %s"%headers["content-length"])
if limit is not None and l > limit:
raise ProxyError(509, "HTTP Body too large. Limit is %s, content-length was %s"%(limit, l))
content = rfile.read(l)
elif all:
content = rfile.read(limit if limit else None)
else:
content = ""
return content
def parse_http_protocol(s):
if not s.startswith("HTTP/"):
return None
major, minor = s.split('/')[1].split('.')
major = int(major)
minor = int(minor)
return major, minor
def parse_init_connect(line):
try:
method, url, protocol = string.split(line)
except ValueError:
return None
if method != 'CONNECT':
return None
try:
host, port = url.split(":")
except ValueError:
return None
port = int(port)
httpversion = parse_http_protocol(protocol)
if not httpversion:
return None
return host, port, httpversion
def parse_init_proxy(line):
try:
method, url, protocol = string.split(line)
except ValueError:
return None
parts = utils.parse_url(url)
if not parts:
return None
scheme, host, port, path = parts
httpversion = parse_http_protocol(protocol)
if not httpversion:
return None
return method, scheme, host, port, path, httpversion
def parse_init_http(line):
"""
Returns (method, url, httpversion)
"""
try:
method, url, protocol = string.split(line)
except ValueError:
return None
if not (url.startswith("/") or url == "*"):
return None
httpversion = parse_http_protocol(protocol)
if not httpversion:
return None
return method, url, httpversion
def request_connection_close(httpversion, headers):
"""
Checks the request to see if the client connection should be closed.
"""
if "connection" in headers:
for value in ",".join(headers['connection']).split(","):
value = value.strip()
if value == "close":
return True
elif value == "keep-alive":
return False
# HTTP 1.1 connections are assumed to be persistent
if httpversion == (1, 1):
return False
return True
def response_connection_close(httpversion, headers):
"""
Checks the response to see if the client connection should be closed.
"""
if request_connection_close(httpversion, headers):
return True
elif not has_chunked_encoding(headers) and "content-length" in headers:
return True
return False
def read_http_body_request(rfile, wfile, headers, httpversion, limit):
if "expect" in headers:
# FIXME: Should be forwarded upstream
expect = ",".join(headers['expect'])
if expect == "100-continue" and httpversion >= (1, 1):
wfile.write('HTTP/1.1 100 Continue\r\n')
wfile.write('Proxy-agent: %s\r\n'%version.NAMEVERSION)
wfile.write('\r\n')
del headers['expect']
return read_http_body(rfile, headers, False, limit)
class RequestReplayThread(threading.Thread):
def __init__(self, config, flow, masterq):
self.config, self.flow, self.masterq = config, flow, masterq
threading.Thread.__init__(self)
def run(self):
try:
r = self.flow.request
server = ServerConnection(self.config, r.scheme, r.host, r.port)
server.send(r)
response = server.read_response(r)
response._send(self.masterq)
except ProxyError, v:
err = flow.Error(self.flow.request, v.msg)
err._send(self.masterq)
except netlib.NetLibError, v:
raise ProxyError(502, v)
class ServerConnection(netlib.TCPClient):
def __init__(self, config, scheme, host, port):
clientcert = None
if config.clientcerts:
path = os.path.join(config.clientcerts, self.host) + ".pem"
if os.path.exists(clientcert):
clientcert = path
netlib.TCPClient.__init__(
self,
True if scheme == "https" else False,
host,
port,
clientcert
)
self.config, self.scheme = config, scheme
self.requestcount = 0
def send(self, request):
self.requestcount += 1
try:
d = request._assemble()
if not d:
raise ProxyError(502, "Incomplete request could not not be readied for transmission.")
self.wfile.write(d)
self.wfile.flush()
except socket.error, err:
raise ProxyError(502, 'Error sending data to "%s": %s' % (request.host, err))
def read_response(self, request):
line = self.rfile.readline()
if line == "\r\n" or line == "\n": # Possible leftover from previous message
line = self.rfile.readline()
if not line:
raise ProxyError(502, "Blank server response.")
parts = line.strip().split(" ", 2)
if len(parts) == 2: # handle missing message gracefully
parts.append("")
if not len(parts) == 3:
raise ProxyError(502, "Invalid server response: %s."%line)
proto, code, msg = parts
httpversion = parse_http_protocol(proto)
if httpversion is None:
raise ProxyError(502, "Invalid HTTP version: %s."%httpversion)
try:
code = int(code)
except ValueError:
raise ProxyError(502, "Invalid server response: %s."%line)
headers = read_headers(self.rfile)
if code >= 100 and code <= 199:
return self.read_response()
if request.method == "HEAD" or code == 204 or code == 304:
content = ""
else:
content = read_http_body(self.rfile, headers, True, self.config.body_size_limit)
return flow.Response(request, httpversion, code, msg, headers, content, self.cert)
def terminate(self):
try:
if not self.wfile.closed:
self.wfile.flush()
self.sock.close()
except IOError:
pass
class ProxyHandler(netlib.BaseHandler):
def __init__(self, config, connection, client_address, server, q):
self.mqueue = q
self.config = config
self.server_conn = None
self.proxy_connect_state = None
netlib.BaseHandler.__init__(self, connection, client_address, server)
def handle(self):
cc = flow.ClientConnect(self.client_address)
cc._send(self.mqueue)
while self.handle_request(cc) and not cc.close:
pass
cc.close = True
cd = flow.ClientDisconnect(cc)
cd._send(self.mqueue)
def server_connect(self, scheme, host, port):
sc = self.server_conn
if sc and (scheme, host, port) != (sc.scheme, sc.host, sc.port):
sc.terminate()
self.server_conn = None
if not self.server_conn:
try:
self.server_conn = ServerConnection(self.config, scheme, host, port)
except netlib.NetLibError, v:
raise ProxyError(502, v)
def handle_request(self, cc):
try:
request, err = None, None
try:
request = self.read_request(cc)
except IOError, v:
raise IOError, "Reading request: %s"%v
if request is None:
return
cc.requestcount += 1
app = self.server.apps.get(request)
if app:
app.serve(request, self.wfile)
else:
request = request._send(self.mqueue)
if request is None:
return
if isinstance(request, flow.Response):
response = request
request = False
response = response._send(self.mqueue)
else:
if self.config.reverse_proxy:
scheme, host, port = self.config.reverse_proxy
else:
scheme, host, port = request.scheme, request.host, request.port
self.server_connect(scheme, host, port)
self.server_conn.send(request)
try:
response = self.server_conn.read_response(request)
except IOError, v:
raise IOError, "Reading response: %s"%v
response = response._send(self.mqueue)
if response is None:
self.server_conn.terminate()
if response is None:
return
self.send_response(response)
if request_connection_close(request.httpversion, request.headers):
return
# We could keep the client connection when the server
# connection needs to go away. However, we want to mimic
# behaviour as closely as possible to the client, so we
# disconnect.
if response_connection_close(response.httpversion, response.headers):
return
except IOError, v:
cc.connection_error = v
except ProxyError, e:
cc.connection_error = "%s: %s"%(e.code, e.msg)
if request:
err = flow.Error(request, e.msg)
err._send(self.mqueue)
self.send_error(e.code, e.msg)
else:
return True
def find_cert(self, host, port):
if self.config.certfile:
return self.config.certfile
else:
sans = []
if self.config.upstream_cert:
cert = certutils.get_remote_cert(host, port)
sans = cert.altnames
host = cert.cn
ret = certutils.dummy_cert(self.config.certdir, self.config.cacert, host, sans)
time.sleep(self.config.cert_wait_time)
if not ret:
raise ProxyError(502, "mitmproxy: Unable to generate dummy cert.")
return ret
def read_request(self, client_conn):
line = self.rfile.readline()
if line == "\r\n" or line == "\n": # Possible leftover from previous message
line = self.rfile.readline()
if line == "":
return None
if self.config.transparent_proxy:
host, port = self.config.transparent_proxy["resolver"].original_addr(self.connection)
if port in self.config.transparent_proxy["sslports"]:
scheme = "https"
certfile = self.find_cert(host, port)
self.convert_to_ssl(certfile, self.config.certfile or self.config.cacert)
else:
scheme = "http"
method, path, httpversion = parse_init_http(line)
headers = read_headers(self.rfile)
content = read_http_body_request(
self.rfile, self.wfile, headers, httpversion, self.config.body_size_limit
)
return flow.Request(client_conn, httpversion, host, port, "http", method, path, headers, content)
elif self.config.reverse_proxy:
scheme, host, port = self.config.reverse_proxy
method, path, httpversion = parse_init_http(line)
headers = read_headers(self.rfile)
content = read_http_body_request(
self.rfile, self.wfile, headers, httpversion, self.config.body_size_limit
)
return flow.Request(client_conn, httpversion, host, port, "http", method, path, headers, content)
else:
if line.startswith("CONNECT"):
host, port, httpversion = parse_init_connect(line)
# FIXME: Discard additional headers sent to the proxy. Should I expose
# these to users?
while 1:
d = self.rfile.readline()
if d == '\r\n' or d == '\n':
break
self.wfile.write(
'HTTP/1.1 200 Connection established\r\n' +
('Proxy-agent: %s\r\n'%version.NAMEVERSION) +
'\r\n'
)
self.wfile.flush()
certfile = self.find_cert(host, port)
self.convert_to_ssl(certfile, self.config.certfile or self.config.cacert)
self.proxy_connect_state = (host, port, httpversion)
line = self.rfile.readline(line)
if self.proxy_connect_state:
host, port, httpversion = self.proxy_connect_state
method, path, httpversion = parse_init_http(line)
headers = read_headers(self.rfile)
content = read_http_body_request(
self.rfile, self.wfile, headers, httpversion, self.config.body_size_limit
)
return flow.Request(client_conn, httpversion, host, port, "https", method, path, headers, content)
else:
method, scheme, host, port, path, httpversion = parse_init_proxy(line)
headers = read_headers(self.rfile)
content = read_http_body_request(
self.rfile, self.wfile, headers, httpversion, self.config.body_size_limit
)
return flow.Request(client_conn, httpversion, host, port, scheme, method, path, headers, content)
def send_response(self, response):
d = response._assemble()
if not d:
raise ProxyError(502, "Incomplete response could not not be readied for transmission.")
self.wfile.write(d)
self.wfile.flush()
def send_error(self, code, body):
try:
import BaseHTTPServer
response = BaseHTTPServer.BaseHTTPRequestHandler.responses[code][0]
self.wfile.write("HTTP/1.1 %s %s\r\n" % (code, response))
self.wfile.write("Server: %s\r\n"%version.NAMEVERSION)
self.wfile.write("Connection: close\r\n")
self.wfile.write("Content-type: text/html\r\n")
self.wfile.write("\r\n")
self.wfile.write('<html><head>\n<title>%d %s</title>\n</head>\n'
'<body>\n%s\n</body>\n</html>' % (code, response, body))
self.wfile.flush()
except:
pass
class ProxyServerError(Exception): pass
class ProxyServer(netlib.TCPServer):
allow_reuse_address = True
bound = True
def __init__(self, config, port, address=''):
"""
Raises ProxyServerError if there's a startup problem.
"""
self.config, self.port, self.address = config, port, address
try:
netlib.TCPServer.__init__(self, (address, port))
except socket.error, v:
raise ProxyServerError('Error starting proxy server: ' + v.strerror)
self.masterq = None
self.certdir = tempfile.mkdtemp(prefix="mitmproxy")
config.certdir = self.certdir
self.apps = wsgi.AppRegistry()
def start_slave(self, klass, masterq):
slave = klass(masterq, self)
slave.start()
def set_mqueue(self, q):
self.masterq = q
def handle_connection(self, request, client_address):
ProxyHandler(self.config, request, client_address, self, self.masterq)
def shutdown(self):
netlib.TCPServer.shutdown(self)
try:
shutil.rmtree(self.certdir)
except OSError:
pass
class DummyServer:
bound = False
def __init__(self, config):
self.config = config
def start_slave(self, klass, masterq):
pass
def shutdown(self):
pass
# Command-line utils
def certificate_option_group(parser):
group = optparse.OptionGroup(parser, "SSL")
group.add_option(
"--cert", action="store",
type = "str", dest="cert", default=None,
help = "User-created SSL certificate file."
)
group.add_option(
"--client-certs", action="store",
type = "str", dest = "clientcerts", default=None,
help = "Client certificate directory."
)
parser.add_option_group(group)
def process_proxy_options(parser, options):
if options.cert:
options.cert = os.path.expanduser(options.cert)
if not os.path.exists(options.cert):
parser.error("Manually created certificate does not exist: %s"%options.cert)
cacert = os.path.join(options.confdir, "mitmproxy-ca.pem")
cacert = os.path.expanduser(cacert)
if not os.path.exists(cacert):
certutils.dummy_ca(cacert)
if getattr(options, "cache", None) is not None:
options.cache = os.path.expanduser(options.cache)
body_size_limit = utils.parse_size(options.body_size_limit)
if options.reverse_proxy:
rp = utils.parse_proxy_spec(options.reverse_proxy)
if not rp:
parser.error("Invalid reverse proxy specification: %s"%options.reverse_proxy)
else:
rp = None
if options.clientcerts:
options.clientcerts = os.path.expanduser(options.clientcerts)
if not os.path.exists(options.clientcerts) or not os.path.isdir(options.clientcerts):
parser.error("Client certificate directory does not exist or is not a directory: %s"%options.clientcerts)
return ProxyConfig(
certfile = options.cert,
cacert = cacert,
clientcerts = options.clientcerts,
cert_wait_time = options.cert_wait_time,
body_size_limit = body_size_limit,
upstream_cert = options.upstream_cert,
reverse_proxy = rp
)