#!/usr/bin/env python
#
# Copyright (c) 2016, 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
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"""
Utility to probe USB serial port(s) trying to figure out which one(s)
we have plugged in today.
"""
import sys
import time
import argparse
import serial.tools.list_ports_posix
parser = argparse.ArgumentParser(formatter_class = argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument("-v", "--verbose", action = "store_true", help = "blather about what we're doing")
args = parser.parse_args()
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
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
# This is the query string we send to each USB port we find. It's
# intended to be relatively harmless, at least for either of the HSM
# ports: the final Control-U should prevent the console from trying to
# interpret the RPC command, and the SLIP_END markers should cause
# the RPC server to treat the ASCII control characters as noise.
#
# Yes, this is a total kludge. Useful identifiers for the USB ports
# are are on the wish list for a future revision of the hardware, but
# for the moment, we do what we can with what we have.
probe_string = SLIP_END + Control_U + SLIP_END + RPC_query + SLIP_END + Control_U + Control_M
def looks_like_console(response):
# Check whether we got a known console prompt.
return any(prompt in response for prompt in ("Username:", "Password:", "cryptech>"))
def looks_like_rpc(response):
# Check whether we got something that looks like the response to an RPC version query.
# We skip over the version value itself, as it might change, but we check that it's
# terminated properly. This is fragile, and will need to handle SLIP decoding if
# we ever bump one of the version fields up into the range where the SLIP control
# characters live, but it will do for the moment.
try:
return response[response.index(SLIP_END + RPC_reply) + len(SLIP_END + RPC_reply) + 4] == SLIP_END
except ValueError:
return False
except IndexError:
return False
rpc_hints = None
ports = dict((port, None)
for port, desc, hwid in serial.tools.list_ports_posix.comports()
if "VID:PID=0403:6014" in hwid)
if not ports:
sys.exit("Couldn't find any likely USB ports")
if args.verbose:
print "Candidate USB ports:", ", ".join(ports)
for port in ports:
while True:
try:
ports[port] = serial.Serial(port, 921600, timeout=0.1)
break
except serial.SerialException:
time.sleep(0.2)
for port in ports:
# Do we really need to dole out characters one at a time here?
# Dunno, but this works well enough.
for c in probe_string:
ports[port].write(c)
time.sleep(0.1)
time.sleep(1)
for port in ports:
s = ""
while True:
c = ports[port].read(1)
if len(c) > 0:
s += c
else:
break
if args.verbose:
print "Received from {}: {!r} ({})".format(port, s, ":".join("{:02x}".format(ord(c)) for c in s))
if looks_like_console(s):
print "{} looks like the Cryptech HSM console port".format(port)
if looks_like_rpc(s):
print "{} looks like the Cryptech HSM RPC port".format(port)
