""" 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, Cookie, cookielib, copy import proxy, threading, netstring, filt 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.request, v.msg) err.send(self.masterq) # end nocover class ClientPlaybackState: def __init__(self, flows, exit): self.flows, self.exit = flows, exit self.current = None def count(self): return len(self.flows) def done(self): if len(self.flows) == 0 and not self.current: return True return False def clear(self, flow): """ A request has returned in some way - if this is the one we're servicing, go to the next flow. """ if flow is self.current: self.current = None def tick(self, master, testing=False): """ testing: Disables actual replay for testing. """ if self.flows and not self.current: n = self.flows.pop(0) n.request.client_conn = None self.current = master.handle_request(n.request) if not testing and not self.current.response: #begin nocover master.state.replay_request(self.current, master.masterq) #end nocover elif self.current.response: master.handle_response(self.current.response) class ServerPlaybackState: def __init__(self, headers, flows, exit): """ headers: A case-insensitive list of request headers that should be included in request-response matching. """ self.headers, self.exit = headers, exit self.fmap = {} for i in flows: if i.response: h = self._hash(i) l = self.fmap.setdefault(self._hash(i), []) l.append(i) def count(self): return sum([len(i) for i in self.fmap.values()]) 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), ] if self.headers: hdrs = [] for i in self.headers: v = r.headers.get(i, []) # Slightly subtle: we need to convert everything to strings # to prevent a mismatch between unicode/non-unicode. v = [str(x) for x in v] hdrs.append((i, v)) key.append(repr(hdrs)) 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 StickyCookieState: def __init__(self, flt): """ flt: A compiled filter. """ self.jar = {} self.flt = flt def ckey(self, m, f): """ Returns a (domain, port, path) tuple. """ return ( m["domain"] or f.request.host, f.request.port, m["path"] or "/" ) def handle_response(self, f): for i in f.response.headers.get("set-cookie", []): c = Cookie.SimpleCookie(i) m = c.values()[0] k = self.ckey(m, f) if cookielib.domain_match(f.request.host, k[0]): self.jar[self.ckey(m, f)] = m def handle_request(self, f): if f.match(self.flt): cs = [] for i in self.jar.keys(): match = [ cookielib.domain_match(i[0], f.request.host), f.request.port == i[1], f.request.path.startswith(i[2]) ] if all(match): l = f.request.headers.setdefault("cookie", []) f.request.stickycookie = True l.append(self.jar[i].output(header="").strip()) class Flow: def __init__(self, request): self.request = request self.response, self.error = None, None self.intercepting = False self._backup = 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 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 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 flow_count(self): return len(self.flow_map) def active_flow_count(self): c = 0 for i in self.flow_list: if not i.response and not i.error: c += 1 return c 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 self.server_playback = None self.client_playback = None self.scripts = {} self.kill_nonreplay = False self.stickycookie_state = False def _runscript(self, f, script): #begin nocover raise NotImplementedError #end nocover def set_response_script(self, s): self.scripts["response"] = s def set_request_script(self, s): self.scripts["request"] = s def set_stickycookie(self, txt): if txt: flt = filt.parse(txt) if not flt: return "Invalid filter expression." self.stickycookie_state = StickyCookieState(flt) else: self.stickycookie_state = None def start_client_playback(self, flows, exit): """ flows: A list of flows. """ self.client_playback = ClientPlaybackState(flows, exit) def start_server_playback(self, flows, kill, headers, exit): """ flows: A list of flows. kill: Boolean, should we kill requests not part of the replay? """ self.server_playback = ServerPlaybackState(headers, flows, exit) self.kill_nonreplay = kill def do_server_playback(self, flow): """ This method should be called by child classes in the handle_request handler. Returns True if playback has taken place, None if not. """ if self.server_playback: rflow = self.server_playback.next_flow(flow) if not rflow: return None response = proxy.Response.from_state(flow.request, rflow.response.get_state()) response.set_replay() flow.response = response flow.request.ack(response) return True return None def tick(self, q): if self.client_playback: e = [ self.client_playback.done(), self.client_playback.exit, self.state.active_flow_count() == 0 ] if all(e): self.shutdown() self.client_playback.tick(self) if self.server_playback: if self.server_playback.exit and self.server_playback.count() == 0: self.shutdown() controller.Master.tick(self, q) 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) if self.client_playback: self.client_playback.clear(f) r.ack() return f def handle_request(self, r): f = self.state.add_request(r) if self.stickycookie_state: self.stickycookie_state.handle_request(f) if "request" in self.scripts: self._runscript(f, self.scripts["request"]) if self.server_playback: pb = self.do_server_playback(f) if not pb: if self.kill_nonreplay: self.state.kill_flow(f) else: r.ack() return f def handle_response(self, r): f = self.state.add_response(r) if self.client_playback: self.client_playback.clear(f) if not f: r.ack() if self.stickycookie_state: self.stickycookie_state.handle_response(f) if "response" in self.scripts: self._runscript(f, self.scripts["response"]) 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)