mitmproxy/libmproxy/flow.py
Aldo Cortesi deb79a9c5a Add a simple server playback state object.
We use a loose hash to match incoming requests with recorded flows. At the
moment, this hash is over the host, port, scheme, method, path and content of
the request. Note that headers are not included here - if we do want to include
headers, we would have to do some work to normalize them to remove variations
between user agents, header order, etc. etc.
2011-02-21 08:47:19 +13:00

379 lines
10 KiB
Python

"""
This module provides more sophisticated flow tracking. These match requests
with their responses, and provide filtering and interception facilities.
"""
import subprocess, base64, sys, json, hashlib
import proxy, threading, netstring
import controller
class RunException(Exception):
def __init__(self, msg, returncode, errout):
Exception.__init__(self, msg)
self.returncode = returncode
self.errout = errout
# begin nocover
class RequestReplayThread(threading.Thread):
def __init__(self, flow, masterq):
self.flow, self.masterq = flow, masterq
threading.Thread.__init__(self)
def run(self):
try:
server = proxy.ServerConnection(self.flow.request)
server.send_request(self.flow.request)
response = server.read_response()
response.send(self.masterq)
except proxy.ProxyError, v:
err = proxy.Error(self.flow.client_conn, v.msg)
err.send(self.masterq)
# end nocover
class ServerPlaybackState:
def __init__(self):
self.fmap = {}
def __len__(self):
return sum([len(i) for i in self.fmap.values()])
def load(self, flows):
"""
Load a sequence of flows. We assume that the sequence is in
chronological order.
"""
for i in flows:
h = self._hash(i)
l = self.fmap.setdefault(self._hash(i), [])
l.append(i)
def _hash(self, flow):
"""
Calculates a loose hash of the flow request.
"""
r = flow.request
key = [
str(r.host),
str(r.port),
str(r.scheme),
str(r.method),
str(r.path),
str(r.content),
]
return hashlib.sha256(repr(key)).digest()
def next_flow(self, request):
"""
Returns the next flow object, or None if no matching flow was
found.
"""
l = self.fmap.get(self._hash(request))
if not l:
return None
return l.pop(0)
class Flow:
def __init__(self, request):
self.request = request
self.response, self.error = None, None
self.intercepting = False
self._backup = None
def script_serialize(self):
data = self.get_state()
return json.dumps(data)
@classmethod
def script_deserialize(klass, data):
try:
data = json.loads(data)
except Exception:
return None
return klass.from_state(data)
def run_script(self, path):
"""
Run a script on a flow.
Returns a (flow, stderr output) tuple, or raises RunException if
there's an error.
"""
self.backup()
data = self.script_serialize()
try:
p = subprocess.Popen(
[path],
stdout=subprocess.PIPE,
stdin=subprocess.PIPE,
stderr=subprocess.PIPE,
)
except OSError, e:
raise RunException(e.args[1], None, None)
so, se = p.communicate(data)
if p.returncode:
raise RunException(
"Script returned error code %s"%p.returncode,
p.returncode,
se
)
f = Flow.script_deserialize(so)
if not f:
raise RunException(
"Invalid response from script.",
p.returncode,
se
)
self.load_state(f.get_state())
return se
def get_state(self, nobackup=False):
d = dict(
request = self.request.get_state() if self.request else None,
response = self.response.get_state() if self.response else None,
error = self.error.get_state() if self.error else None,
)
if nobackup:
d["backup"] = None
else:
d["backup"] = self._backup
return d
def load_state(self, state):
self._backup = state["backup"]
if self.request:
self.request.load_state(state["request"])
else:
self.request = proxy.Request.from_state(state["request"])
if state["response"]:
if self.response:
self.response.load_state(state["response"])
else:
self.response = proxy.Response.from_state(self.request, state["response"])
else:
self.response = None
if state["error"]:
if self.error:
self.error.load_state(state["error"])
else:
self.error = proxy.Error.from_state(state["error"])
else:
self.error = None
@classmethod
def from_state(klass, state):
f = klass(None)
f.load_state(state)
return f
def __eq__(self, other):
return self.get_state() == other.get_state()
def modified(self):
# FIXME: Save a serialization in backup, compare current with
# backup to detect if flow has _really_ been modified.
if self._backup:
return True
else:
return False
def backup(self):
self._backup = self.get_state(nobackup=True)
def revert(self):
if self._backup:
self.load_state(self._backup)
self._backup = None
def match(self, pattern):
if pattern:
if self.response:
return pattern(self.response)
elif self.request:
return pattern(self.request)
return False
def kill(self):
if self.request and not self.request.acked:
self.request.ack(None)
elif self.response and not self.response.acked:
self.response.ack(None)
self.intercepting = False
def intercept(self):
self.intercepting = True
def accept_intercept(self):
if self.request:
if not self.request.acked:
self.request.ack()
elif self.response and not self.response.acked:
self.response.ack()
self.intercepting = False
class State:
def __init__(self):
self.client_connections = []
self.flow_map = {}
self.flow_list = []
# These are compiled filt expressions:
self.limit = None
self.intercept = None
def clientconnect(self, cc):
self.client_connections.append(cc)
def clientdisconnect(self, dc):
"""
Start a browser connection.
"""
self.client_connections.remove(dc.client_conn)
def add_request(self, req):
"""
Add a request to the state. Returns the matching flow.
"""
f = Flow(req)
self.flow_list.insert(0, f)
self.flow_map[req] = f
return f
def add_response(self, resp):
"""
Add a response to the state. Returns the matching flow.
"""
f = self.flow_map.get(resp.request)
if not f:
return False
f.response = resp
return f
def add_error(self, err):
"""
Add an error response to the state. Returns the matching flow, or
None if there isn't one.
"""
f = self.flow_map.get(err.request) if err.request else None
if not f:
return None
f.error = err
return f
def load_flows(self, flows):
self.flow_list.extend(flows)
for i in flows:
self.flow_map[i.request] = i
def set_limit(self, limit):
"""
Limit is a compiled filter expression, or None.
"""
self.limit = limit
@property
def view(self):
if self.limit:
return tuple([i for i in self.flow_list if i.match(self.limit)])
else:
return tuple(self.flow_list[:])
def delete_flow(self, f):
if not f.intercepting:
if f.request in self.flow_map:
del self.flow_map[f.request]
self.flow_list.remove(f)
return True
return False
def clear(self):
for i in self.flow_list[:]:
self.delete_flow(i)
def accept_all(self):
for i in self.flow_list[:]:
i.accept_intercept()
def kill_flow(self, f):
f.kill()
self.delete_flow(f)
def revert(self, f):
f.revert()
def replay_request(self, f, masterq):
"""
Returns None if successful, or error message if not.
"""
#begin nocover
if f.intercepting:
return "Can't replay while intercepting..."
if f.request:
f.backup()
f.request.set_replay()
if f.request.content:
f.request.headers["content-length"] = [str(len(f.request.content))]
f.response = None
f.error = None
rt = RequestReplayThread(f, masterq)
rt.start()
#end nocover
class FlowMaster(controller.Master):
def __init__(self, server, state):
controller.Master.__init__(self, server)
self.state = state
def handle_clientconnect(self, r):
self.state.clientconnect(r)
r.ack()
def handle_clientdisconnect(self, r):
self.state.clientdisconnect(r)
r.ack()
def handle_error(self, r):
f = self.state.add_error(r)
r.ack()
return f
def handle_request(self, r):
return self.state.add_request(r)
def handle_response(self, r):
f = self.state.add_response(r)
if not f:
r.ack()
return f
class FlowWriter:
def __init__(self, fo):
self.fo = fo
self.ns = netstring.FileEncoder(fo)
def add(self, flow):
d = flow.get_state()
s = json.dumps(d)
self.ns.write(s)
class FlowReader:
def __init__(self, fo):
self.fo = fo
self.ns = netstring.decode_file(fo)
def stream(self):
"""
Yields Flow objects from the dump.
"""
for i in self.ns:
data = json.loads(i)
yield Flow.from_state(data)