#!/usr/bin/env python # # Copyright (c) 2016-2017, NORDUnet A/S All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are # met: # - Redistributions of source code must retain the above copyright notice, # this list of conditions and the following disclaimer. # # - Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # # - Neither the name of the NORDUnet nor the names of its contributors may # be used to endorse or promote products derived from this software # without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS # IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED # TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A # PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT # HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED # TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR # PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF # LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. """ Implementation of Cryptech RPC protocol multiplexer in Python. Unlike the original C implementation, this uses SLIP encapsulation over a SOCK_STREAM channel, because support for SOCK_SEQPACKET is not what we might wish. We outsource all the heavy lifting for serial and network I/O to the PySerial and Tornado libraries, respectively. """ import os import sys import time import struct import atexit import weakref import logging import argparse import logging.handlers import serial import serial.tools.list_ports_posix import tornado.tcpserver import tornado.iostream import tornado.netutil import tornado.ioloop import tornado.queues import tornado.locks import tornado.gen logger = logging.getLogger("cryptech_muxd") SLIP_END = chr(0300) # Indicates end of SLIP packet SLIP_ESC = chr(0333) # Indicates byte stuffing SLIP_ESC_END = chr(0334) # ESC ESC_END means END data byte SLIP_ESC_ESC = chr(0335) # ESC ESC_ESC means ESC data byte Control_U = chr(0025) # Console: clear line Control_M = chr(0015) # Console: end of line def slip_encode(buffer): "Encode a buffer using SLIP encapsulation." return SLIP_END + buffer.replace(SLIP_ESC, SLIP_ESC + SLIP_ESC_ESC).replace(SLIP_END, SLIP_ESC + SLIP_ESC_END) + SLIP_END def slip_decode(buffer): "Decode a SLIP-encapsulated buffer." return buffer.strip(SLIP_END).replace(SLIP_ESC + SLIP_ESC_END, SLIP_END).replace(SLIP_ESC + SLIP_ESC_ESC, SLIP_ESC) def client_handle_get(msg): "Extract client_handle field from a Cryptech RPC message." return struct.unpack(">L", msg[4:8])[0] def client_handle_set(msg, handle): "Replace client_handle field in a Cryptech RPC message." return msg[:4] + struct.pack(">L", handle) + msg[8:] class SerialIOStream(tornado.iostream.BaseIOStream): """ Implementation of a Tornado IOStream over a PySerial device. """ def __init__(self, device): self.serial = serial.Serial(device, 921600, timeout = 0, write_timeout = 0) self.serial_device = device super(SerialIOStream, self).__init__() def fileno(self): return self.serial.fileno() def close_fd(self): self.serial.close() def write_to_fd(self, data): return self.serial.write(data) def read_from_fd(self): return self.serial.read(self.read_chunk_size) or None class PFUnixServer(tornado.tcpserver.TCPServer): """ Variant on tornado.tcpserver.TCPServer, listening on a PF_UNIX (aka PF_LOCAL) socket instead of a TCP socket. """ def __init__(self, serial_stream, socket_filename, mode = 0600): super(PFUnixServer, self).__init__() self.serial = serial_stream self.socket_filename = socket_filename self.add_socket(tornado.netutil.bind_unix_socket(socket_filename, mode)) atexit.register(self.atexit_unlink) def atexit_unlink(self): try: os.unlink(self.socket_filename) except: pass class RPCIOStream(SerialIOStream): """ Tornado IOStream for a serial RPC channel. """ def __init__(self, device): super(RPCIOStream, self).__init__(device) self.queues = weakref.WeakValueDictionary() self.rpc_input_lock = tornado.locks.Lock() @tornado.gen.coroutine def rpc_input(self, query, handle, queue): "Send a query to the HSM." logger.debug("RPC send: %s", ":".join("{:02x}".format(ord(c)) for c in query)) self.queues[handle] = queue with (yield self.rpc_input_lock.acquire()): yield self.write(query) logger.debug("RPC sent") @tornado.gen.coroutine def rpc_output_loop(self): "Handle reply stream HSM -> network." while True: try: logger.debug("RPC UART read") reply = yield self.read_until(SLIP_END) except tornado.iostream.StreamClosedError: logger.info("RPC UART closed") for q in self.queues.itervalues(): q.put_nowait(None) return logger.debug("RPC recv: %s", ":".join("{:02x}".format(ord(c)) for c in reply)) try: handle = client_handle_get(slip_decode(reply)) except: continue logger.debug("RPC queue put: handle 0x%x, qsize %s, maxsize %s", handle, self.queues[handle].qsize(), self.queues[handle].maxsize) self.queues[handle].put_nowait(reply) class QueuedStreamClosedError(tornado.iostream.StreamClosedError): "Deferred StreamClosedError passed throught a Queue." class RPCServer(PFUnixServer): """ Serve multiplexed Cryptech RPC over a PF_UNIX socket. """ @tornado.gen.coroutine def handle_stream(self, stream, address): "Handle one network connection." handle = stream.socket.fileno() queue = tornado.queues.Queue() logger.info("RPC connected %r, handle 0x%x", stream, handle) while True: try: logger.debug("RPC socket read, handle 0x%x", handle) query = yield stream.read_until(SLIP_END) if len(query) < 9: continue query = slip_encode(client_handle_set(slip_decode(query), handle)) yield self.serial.rpc_input(query, handle, queue) logger.debug("RPC queue wait, handle 0x%x", handle) reply = yield queue.get() if reply is None: raise QueuedStreamClosedError() logger.debug("RPC socket write, handle 0x%x", handle) yield stream.write(SLIP_END + reply) except tornado.iostream.StreamClosedError: logger.info("RPC closing %r, handle 0x%x", stream, handle) stream.close() return class CTYIOStream(SerialIOStream): """ Tornado IOStream for a serial console channel. """ def __init__(self, device): super(CTYIOStream, self).__init__(device) self.attached_cty = None @tornado.gen.coroutine def cty_output_loop(self): while True: try: buffer = yield self.read_bytes(self.read_chunk_size, partial = True) except tornado.iostream.StreamClosedError: logger.info("CTY UART closed") if self.attached_cty is not None: self.attached_cty.close() return try: if self.attached_cty is not None: yield self.attached_cty.write(buffer) except tornado.iostream.StreamClosedError: pass class CTYServer(PFUnixServer): """ Serve Cryptech console over a PF_UNIX socket. """ @tornado.gen.coroutine def handle_stream(self, stream, address): "Handle one network connection." if self.serial.attached_cty is not None: yield stream.write("[Console already in use, sorry]\n") stream.close() return logger.info("CTY connected to %r", stream) try: self.serial.attached_cty = stream while self.serial.attached_cty is stream: yield self.serial.write((yield stream.read_bytes(1024, partial = True))) except tornado.iostream.StreamClosedError: stream.close() finally: logger.info("CTY disconnected from %r", stream) if self.serial.attached_cty is stream: self.serial.attached_cty = None class ProbeIOStream(SerialIOStream): """ Tornado IOStream for probing a serial port. This is nasty. """ def __init__(self, device): super(ProbeIOStream, self).__init__(device) @classmethod @tornado.gen.coroutine def run_probes(cls, args): if args.rpc_device is not None and args.cty_device is not None: return if args.probe: devs = set(args.probe) else: devs = set(str(port) for port, desc, hwid in serial.tools.list_ports_posix.comports() if "VID:PID=0403:6014" in hwid) devs.discard(args.rpc_device) devs.discard(args.cty_device) if not devs: return logging.debug("Probing candidate devices %s", " ".join(devs)) results = yield dict((dev, ProbeIOStream(dev).run_probe()) for dev in devs) for dev, result in results.iteritems(): if result == "cty" and args.cty_device is None: logger.info("Selecting %s as CTY device", dev) args.cty_device = dev if result == "rpc" and args.rpc_device is None: logger.info("Selecting %s as RPC device", dev) args.rpc_device = dev @tornado.gen.coroutine def run_probe(self): RPC_query = chr(0) * 8 # client_handle = 0, function code = RPC_FUNC_GET_VERSION RPC_reply = chr(0) * 12 # opcode = RPC_FUNC_GET_VERSION, client_handle = 0, valret = HAL_OK probe_string = SLIP_END + Control_U + SLIP_END + RPC_query + SLIP_END + Control_U + Control_M yield self.write(probe_string) yield tornado.gen.sleep(0.5) response = yield self.read_bytes(self.read_chunk_size, partial = True) logger.debug("Probing %s: %r %s", self.serial_device, response, ":".join("{:02x}".format(ord(c)) for c in response)) is_cty = any(prompt in response for prompt in ("Username:", "Password:", "cryptech>")) try: is_rpc = response[response.index(SLIP_END + RPC_reply) + len(SLIP_END + RPC_reply) + 4] == SLIP_END except ValueError: is_rpc = False except IndexError: is_rpc = False assert not is_cty or not is_rpc result = None if is_cty: result = "cty" yield self.write(Control_U) if is_rpc: result = "rpc" yield self.write(SLIP_END) self.close() raise tornado.gen.Return(result) @tornado.gen.coroutine def main(): parser = argparse.ArgumentParser(formatter_class = argparse.ArgumentDefaultsHelpFormatter) parser.add_argument("-v", "--verbose", action = "count", help = "blather about what we're doing") parser.add_argument("-l", "--log-file", help = "log to file instead of stderr") parser.add_argument("-p", "--probe", nargs = "*", metavar = "DEVICE", help = "probe for device UARTs") parser.add_argument("--rpc-device", help = "RPC serial device name", default = os.getenv("CRYPTECH_RPC_CLIENT_SERIAL_DEVICE")) parser.add_argument("--rpc-socket", help = "RPC PF_UNIX socket name", default = os.getenv("CRYPTECH_RPC_CLIENT_SOCKET_NAME", "/tmp/.cryptech_muxd.rpc")) parser.add_argument("--cty-device", help = "CTY serial device name", default = os.getenv("CRYPTECH_CTY_CLIENT_SERIAL_DEVICE")) parser.add_argument("--cty-socket", help = "CTY PF_UNIX socket name", default = os.getenv("CRYPTECH_CTY_CLIENT_SOCKET_NAME", "/tmp/.cryptech_muxd.cty")) args = parser.parse_args() if args.log_file is not None: logging.getLogger().handlers[:] = [logging.handlers.WatchedFileHandler(args.log_file)] logging.getLogger().handlers[0].setFormatter( logging.Formatter("%(asctime)-15s %(name)s[%(process)d]:%(levelname)s: %(message)s", "%Y-%m-%d %H:%M:%S")) if args.verbose: logging.getLogger().setLevel(logging.DEBUG if args.verbose > 1 else logging.INFO) if args.probe is not None: yield ProbeIOStream.run_probes(args) futures = [] if args.rpc_device is None: logger.warn("No RPC device found") else: rpc_stream = RPCIOStream(device = args.rpc_device) rpc_server = RPCServer(rpc_stream, args.rpc_socket) futures.append(rpc_stream.rpc_output_loop()) if args.cty_device is None: logger.warn("No CTY device found") else: cty_stream = CTYIOStream(device = args.cty_device) cty_server = CTYServer(cty_stream, args.cty_socket) futures.append(cty_stream.cty_output_loop()) # Might want to use WaitIterator(dict(...)) here so we can # diagnose and restart output loops if they fail? if futures: yield futures if __name__ == "__main__": try: tornado.ioloop.IOLoop.current().run_sync(main) except KeyboardInterrupt: pass ='#n339'>339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445