sw/libhal - Cryptech libhal: crypto software, HSM management, RPC

Age	Commit message (Collapse)	Author
2017-05-31	Automatic logout when client disconnects or muxd restarts.	Rob Austein
	The HSM itself should be detecting carrier drop on its RPC port, but I haven't figured out where the DCD bit is hiding in the STM32 UART API, and the muxd has to be involved in this in any case, since only the muxd knows when an individual client connection has dropped. So, for the moment, we handle all of this in the muxd.
2017-05-03	Tweak PySerial write_timeout setting.	Rob Austein

2017-04-26	Don't intefere with sys.exit().	Rob Austein

2017-04-23	Log exit conditions	Rob Austein

2017-04-15	Write to console socket and console log in parallel.	Rob Austein
	We're using non-blocking I/O in any case, might as well take advantage of it to keep console output a little smoother.
2017-04-15	Add console log support to muxd.	Rob Austein

2017-04-11	Log packet drops.	Rob Austein

2017-04-11	Reject malformed messages from RPC UART, not just too-short ones.	Rob Austein

2017-03-06	Debugging code to track message flow.	Rob Austein

2017-01-12	Probing wants a brief delay after probe string on some machines.	Rob Austein
	Probably reached the point of diminishing returns for trying to get probing to work better. Best option, where practical, is to avoid probing completely; when necessary, best run it once then avoid repeating it. cryptech_muxd will probe if requested, but probing is never going to be reliable. Dedicated VID:PID would be much better.
2017-01-12	Finish logging code, skip initialization for missing devices.	Rob Austein

2017-01-11	Cleanup.	Rob Austein

2017-01-11	Add internal port probing code (like running cryptech_probe first).	Rob Austein
	Internal probe code mostly works, probably about as well as cryptech_probe ever did, but almost certainly needs timeouts around its I/O calls, and perhaps additional error handling. At the moment, it works except when it doesn't, just like cryptech_probe. Some day we'll get away from this kludge, but not today.
2017-01-10	Handle connection close events properly, use logging library.	Rob Austein

2017-01-05	Whack multiplexer to handle console too.	Rob Austein
	Renamed multiplexer to cryptech_muxd, since it now handles both RPC and CTY. Added new program cryptech_console to act as client for CTY multiplexer. Might want to add console logging capability eventually, not today. Probably want to incorporate UART probing (what cryptech_probe does now) eventually, also not today.

#!/usr/bin/env python """ Securely back up private keys from one Cryptech HSM to another. This works by having the destination HSM (the one importing keys) create an RSA keypair (the "KEKEK"), the public key of which can then be imported into the source HSM (the one exporting keys) and used to encrypt AES key encryption keys (KEKs) which in turn can be used to wrap the private keys being transfered. Transfers are encoded in JSON; the underlying ASN.1 formats are SubjectPublicKeyInfo (KEKEK public key) and PKCS #8 EncryptedPrivateKeyInfo (everything else). NOTE WELL: while this process makes it POSSIBLE to back up keys securely, it is not sufficient by itself: the operator MUST make sure only to export keys using a KEKEK known to have been generated by the target HSM. See the unit tests in the source repository for an example of how to fake this in a few lines of Python. YOU HAVE BEEN WARNED. Be careful out there. """ # Diagram of the trivial protocol we're using: # # SOURCE HSM DESTINATION HSM # # Generate and export KEKEK: # hal_rpc_pkey_generate_rsa() # hal_rpc_pkey_get_public_key() # # Load KEKEK public <--------- Export KEKEK public # hal_rpc_pkey_load() # hal_rpc_pkey_export() # # Export PKCS #8 and KEK ----------> Load PKCS #8 and KEK, import key # hal_rpc_pkey_import() import sys import json import uuid import atexit import getpass import argparse from cryptech.libhal import * def main(): parser = argparse.ArgumentParser( formatter_class = argparse.RawDescriptionHelpFormatter, description = __doc__) subparsers = parser.add_subparsers( title = "Commands (use \"--help\" after command name for help with individual commands)", metavar = "") setup_parser = defcmd(subparsers, cmd_setup) export_parser = defcmd(subparsers, cmd_export) import_parser = defcmd(subparsers, cmd_import) setup_mutex_group = setup_parser.add_mutually_exclusive_group() parser.add_argument( "-p", "--pin", help = "wheel PIN") setup_mutex_group.add_argument( "-n", "--new", action = "store_true", help = "force creation of new KEKEK") setup_mutex_group.add_argument( "-u", "--uuid", help = "UUID of existing KEKEK to use") setup_parser.add_argument( "-k", "--keylen", type = int, default = 2048, help = "length of new KEKEK if we need to create one") setup_parser.add_argument( "-o", "--output", type = argparse.FileType("w"), default = "-", help = "output file") export_parser.add_argument( "-i", "--input", type = argparse.FileType("r"), default = "-", help = "input file") export_parser.add_argument( "-o", "--output", type = argparse.FileType("w"), default = "-", help = "output file") import_parser.add_argument( "-i", "--input", type = argparse.FileType("r"), default = "-", help = "input file") args = parser.parse_args() hsm = HSM() try: hsm.login(HAL_USER_WHEEL, args.pin or getpass.getpass("Wheel PIN: ")) except HALError as e: sys.exit("Couldn't log into HSM: {}".format(e)) try: sys.exit(args.func(args, hsm)) finally: hsm.logout() def defcmd(subparsers, func): assert func.__name__.startswith("cmd_") subparser = subparsers.add_parser(func.__name__[4:], description = func.__doc__, help = func.__doc__.strip().splitlines()[0]) subparser.set_defaults(func = func) return subparser def b64(bytes): return bytes.encode("base64").splitlines() def b64join(lines): return "".join(lines).decode("base64") def cmd_setup(args, hsm): """ Set up backup HSM for subsequent import. Generates an RSA keypair with appropriate usage settings to use as a key-encryption-key-encryption-key (KEKEK), and writes the KEKEK to a JSON file for transfer to primary HSM. """ result = {} uuids = [] if args.uuid: uuids.append(args.uuid) elif not args.new: uuids.extend(hsm.pkey_match( type = HAL_KEY_TYPE_RSA_PRIVATE, mask = HAL_KEY_FLAG_USAGE_KEYENCIPHERMENT | HAL_KEY_FLAG_TOKEN, flags = HAL_KEY_FLAG_USAGE_KEYENCIPHERMENT | HAL_KEY_FLAG_TOKEN)) for uuid in uuids: with hsm.pkey_open(uuid) as kekek: if kekek.key_type != HAL_KEY_TYPE_RSA_PRIVATE: sys.stderr.write("Key {} is not an RSA private key\n".format(uuid)) elif (kekek.key_flags & HAL_KEY_FLAG_USAGE_KEYENCIPHERMENT) == 0: sys.stderr.write("Key {} does not allow key encipherment\n".format(uuid)) else: result.update(kekek_uuid = str(kekek.uuid), kekek_pubkey = b64(kekek.public_key)) break if not result and not args.uuid: with hsm.pkey_generate_rsa( keylen = args.keylen, flags = HAL_KEY_FLAG_USAGE_KEYENCIPHERMENT | HAL_KEY_FLAG_TOKEN) as kekek: result.update(kekek_uuid = str(kekek.uuid), kekek_pubkey = b64(kekek.public_key)) if not result: sys.exit("Could not find suitable KEKEK") result.update(comment = "KEKEK public key") json.dump(result, args.output, indent = 4, sort_keys = True) args.output.write("\n") def key_flag_names(flags): names = dict(digitalsignature = HAL_KEY_FLAG_USAGE_DIGITALSIGNATURE, keyencipherment = HAL_KEY_FLAG_USAGE_KEYENCIPHERMENT, dataencipherment = HAL_KEY_FLAG_USAGE_DATAENCIPHERMENT, token = HAL_KEY_FLAG_TOKEN, public = HAL_KEY_FLAG_PUBLIC, exportable = HAL_KEY_FLAG_EXPORTABLE) return ", ".join(sorted(k for k, v in names.iteritems() if (flags & v) != 0)) def cmd_export(args, hsm): """ Export encrypted keys from primary HSM. Takes a JSON file containing KEKEK (generated by running this script's "setup" command against the backup HSM), installs that key on the primary HSM, and backs up keys encrypted to the KEKEK by writing them to another JSON file for transfer to the backup HSM. """ db = json.load(args.input) result = [] kekek = None try: kekek = hsm.pkey_load(der = b64join(db["kekek_pubkey"]), flags = HAL_KEY_FLAG_USAGE_KEYENCIPHERMENT) for uuid in hsm.pkey_match(mask = HAL_KEY_FLAG_EXPORTABLE, flags = HAL_KEY_FLAG_EXPORTABLE): with hsm.pkey_open(uuid) as pkey: if pkey.key_type in (HAL_KEY_TYPE_RSA_PRIVATE, HAL_KEY_TYPE_EC_PRIVATE): pkcs8, kek = kekek.export_pkey(pkey) result.append(dict( comment = "Encrypted private key", pkcs8 = b64(pkcs8), kek = b64(kek), uuid = str(pkey.uuid), flags = pkey.key_flags)) elif pkey.key_type in (HAL_KEY_TYPE_RSA_PUBLIC, HAL_KEY_TYPE_EC_PUBLIC): result.append(dict( comment = "Public key", spki = b64(pkey.public_key), uuid = str(pkey.uuid), flags = pkey.key_flags)) finally: if kekek is not None: kekek.delete() db.update(comment = "Cryptech Alpha encrypted key backup", keys = result) json.dump(db, args.output, indent = 4, sort_keys = True) args.output.write("\n") def cmd_import(args, hsm): """ Import encrypted keys into backup HSM. Takes a JSON file containing a key backup (generated by running this script's "export" command against the primary HSM) and imports keys into the backup HSM. """ db = json.load(args.input) with hsm.pkey_open(uuid.UUID(db["kekek_uuid"]).bytes) as kekek: for k in db["keys"]: pkcs8 = b64join(k.get("pkcs8", "")) spki = b64join(k.get("spki", "")) kek = b64join(k.get("kek", "")) flags = k.get("flags", 0) if pkcs8 and kek: with kekek.import_pkey(pkcs8 = pkcs8, kek = kek, flags = flags) as pkey: print "Imported {} as {}".format(k["uuid"], pkey.uuid) elif spki: with hsm.pkey_load(der = spki, flags = flags) as pkey: print "Loaded {} as {}".format(k["uuid"], pkey.uuid) if __name__ == "__main__": main()