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Diffstat (limited to 'cryptech_muxd')
| -rwxr-xr-x | cryptech_muxd | 422 |
1 files changed, 422 insertions, 0 deletions
diff --git a/cryptech_muxd b/cryptech_muxd new file mode 100755 index 0000000..269ac15 --- /dev/null +++ b/cryptech_muxd @@ -0,0 +1,422 @@ +#!/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 |