mdw@git.distorted.org.uk Git - tripe/blob - keys/tripe-keys.in

   1 #! @PYTHON@
   2 ### -*-python-*-
   3 ###
   4 ### Key management and distribution
   5 ###
   6 ### (c) 2006 Straylight/Edgeware
   7 ###
   8
   9 ###----- Licensing notice ---------------------------------------------------
  10 ###
  11 ### This file is part of Trivial IP Encryption (TrIPE).
  12 ###
  13 ### TrIPE is free software; you can redistribute it and/or modify
  14 ### it under the terms of the GNU General Public License as published by
  15 ### the Free Software Foundation; either version 2 of the License, or
  16 ### (at your option) any later version.
  17 ###
  18 ### TrIPE is distributed in the hope that it will be useful,
  19 ### but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ### GNU General Public License for more details.
  22 ###
  23 ### You should have received a copy of the GNU General Public License
  24 ### along with TrIPE; if not, write to the Free Software Foundation,
  25 ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26
  27 ###--------------------------------------------------------------------------
  28 ### External dependencies.
  29
  30 import catacomb as C
  31 import os as OS
  32 import sys as SYS
  33 import re as RX
  34 import getopt as O
  35 import shutil as SH
  36 import time as T
  37 import filecmp as FC
  38 from cStringIO import StringIO
  39 from errno import *
  40 from stat import *
  41
  42 ###--------------------------------------------------------------------------
  43 ### Useful regular expressions
  44
  45 ## Match a comment or blank line.
  46 rx_comment = RX.compile(r'^\s*(#|$)')
  47
  48 ## Match a KEY = VALUE assignment.
  49 rx_keyval = RX.compile(r'^\s*([-\w]+)(?:\s+(?!=)|\s*=\s*)(|\S|\S.*\S)\s*$')
  50
  51 ## Match a ${KEY} substitution.
  52 rx_dollarsubst = RX.compile(r'\$\{([-\w]+)\}')
  53
  54 ## Match a @TAG@ substitution.
  55 rx_atsubst = RX.compile(r'@([-\w]+)@')
  56
  57 ## Match a single non-alphanumeric character.
  58 rx_nonalpha = RX.compile(r'\W')
  59
  60 ## Match the literal string "<SEQ>".
  61 rx_seq = RX.compile(r'\<SEQ\>')
  62
  63 ## Match a shell metacharacter.
  64 rx_shmeta = RX.compile('[\\s`!"#$&*()\\[\\];\'|<>?\\\\]')
  65
  66 ## Match a character which needs escaping in a shell double-quoted string.
  67 rx_shquote = RX.compile(r'["`$\\]')
  68
  69 ###--------------------------------------------------------------------------
  70 ### Utility functions.
  71
  72 ## Exceptions.
  73 class SubprocessError (Exception): pass
  74 class VerifyError (Exception): pass
  75
  76 ## Program name and identification.
  77 quis = OS.path.basename(SYS.argv[0])
  78 PACKAGE = "@PACKAGE@"
  79 VERSION = "@VERSION@"
  80
  81 def moan(msg):
  82   """Report MSG to standard error."""
  83   SYS.stderr.write('%s: %s\n' % (quis, msg))
  84
  85 def die(msg, rc = 1):
  86   """Report MSG to standard error, and exit with code RC."""
  87   moan(msg)
  88   SYS.exit(rc)
  89
  90 def subst(s, rx, map):
  91   """
  92   Substitute values into a string.
  93
  94   Repeatedly match RX (a compiled regular expression) against the string S.
  95   For each match, extract group 1, and use it as a key to index the MAP;
  96   replace the match by the result.  Finally, return the fully-substituted
  97   string.
  98   """
  99   out = StringIO()
 100   i = 0
 101   for m in rx.finditer(s):
 102     out.write(s[i:m.start()] + map[m.group(1)])
 103     i = m.end()
 104   out.write(s[i:])
 105   return out.getvalue()
 106
 107 def shell_quotify(arg):
 108   """
 109   Quotify ARG to keep the shell happy.
 110
 111   This isn't actually used for invoking commands, just for presentation
 112   purposes; but correctness is still nice.
 113   """
 114   if not rx_shmeta.search(arg):
 115     return arg
 116   elif arg.find("'") == -1:
 117     return "'%s'" % arg
 118   else:
 119     return '"%s"' % rx_shquote.sub(lambda m: '\\' + m.group(0), arg)
 120
 121 def rmtree(path):
 122   """Delete the directory tree given by PATH."""
 123   try:
 124     st = OS.lstat(path)
 125   except OSError, err:
 126     if err.errno == ENOENT:
 127       return
 128     raise
 129   if not S_ISDIR(st.st_mode):
 130     OS.unlink(path)
 131   else:
 132     cwd = OS.getcwd()
 133     try:
 134       OS.chdir(path)
 135       for i in OS.listdir('.'):
 136         rmtree(i)
 137     finally:
 138       OS.chdir(cwd)
 139     OS.rmdir(path)
 140
 141 def zap(file):
 142   """Delete the named FILE if it exists; otherwise do nothing."""
 143   try:
 144     OS.unlink(file)
 145   except OSError, err:
 146     if err.errno == ENOENT: return
 147     raise
 148
 149 def run(args):
 150   """
 151   Run a subprocess whose arguments are given by the string ARGS.
 152
 153   The ARGS are split at word boundaries, and then subjected to configuration
 154   variable substitution (see conf_subst).  Individual argument elements
 155   beginning with `!' are split again into multiple arguments at word
 156   boundaries.
 157   """
 158   args = map(conf_subst, args.split())
 159   nargs = []
 160   for a in args:
 161     if len(a) > 0 and a[0] != '!':
 162       nargs += [a]
 163     else:
 164       nargs += a[1:].split()
 165   args = nargs
 166   print '+ %s' % ' '.join([shell_quotify(arg) for arg in args])
 167   SYS.stdout.flush()
 168   rc = OS.spawnvp(OS.P_WAIT, args[0], args)
 169   if rc != 0:
 170     raise SubprocessError, rc
 171
 172 def hexhyphens(bytes):
 173   """
 174   Convert a byte string BYTES into hex, with hyphens at each 4-byte boundary.
 175   """
 176   out = StringIO()
 177   for i in xrange(0, len(bytes)):
 178     if i > 0 and i % 4 == 0: out.write('-')
 179     out.write('%02x' % ord(bytes[i]))
 180   return out.getvalue()
 181
 182 def fingerprint(kf, ktag):
 183   """
 184   Compute the fingerprint of a key, using the user's selected hash.
 185
 186   KF is the name of a keyfile; KTAG is the tag of the key.
 187   """
 188   h = C.gchashes[conf['fingerprint-hash']]()
 189   k = C.KeyFile(kf)[ktag].fingerprint(h, '-secret')
 190   return h.done()
 191
 192 ###--------------------------------------------------------------------------
 193 ### The configuration file.
 194
 195 ## Exceptions.
 196 class ConfigFileError (Exception): pass
 197
 198 ## The configuration dictionary.
 199 conf = {}
 200
 201 def conf_subst(s):
 202   """
 203   Apply configuration substitutions to S.
 204
 205   That is, for each ${KEY} in S, replace it with the current value of the
 206   configuration variable KEY.
 207   """
 208   return subst(s, rx_dollarsubst, conf)
 209
 210 def conf_read(f):
 211   """
 212   Read the file F and insert assignments into the configuration dictionary.
 213   """
 214   lno = 0
 215   for line in file(f):
 216     lno += 1
 217     if rx_comment.match(line): continue
 218     if line[-1] == '\n': line = line[:-1]
 219     match = rx_keyval.match(line)
 220     if not match:
 221       raise ConfigFileError, "%s:%d: bad line `%s'" % (f, lno, line)
 222     k, v = match.groups()
 223     conf[k] = conf_subst(v)
 224
 225 def conf_defaults():
 226   """
 227   Apply defaults to the configuration dictionary.
 228
 229   Fill in all the interesting configuration variables based on the existing
 230   contents, as described in the manual.
 231   """
 232   for k, v in [('repos-base', 'tripe-keys.tar.gz'),
 233                ('sig-base', 'tripe-keys.sig-<SEQ>'),
 234                ('repos-url', '${base-url}${repos-base}'),
 235                ('sig-url', '${base-url}${sig-base}'),
 236                ('sig-file', '${base-dir}${sig-base}'),
 237                ('repos-file', '${base-dir}${repos-base}'),
 238                ('conf-file', '${base-dir}tripe-keys.conf'),
 239                ('upload-hook', ': run upload hook'),
 240                ('kx', 'dh'),
 241                ('kx-genalg', lambda: {'dh': 'dh',
 242                                       'ec': 'ec'}[conf['kx']]),
 243                ('kx-param-genalg', lambda: {'dh': 'dh-param',
 244                                             'ec': 'ec-param'}[conf['kx']]),
 245                ('kx-param', lambda: {'dh': '-LS -b3072 -B256',
 246                                      'ec': '-Cnist-p256'}[conf['kx']]),
 247                ('kx-attrs', 'serialization=constlen'),
 248                ('kx-expire', 'now + 1 year'),
 249                ('kx-warn-days', '28'),
 250                ('bulk', 'iiv'),
 251                ('cipher', 'rijndael-cbc'),
 252                ('hash', 'sha256'),
 253                ('master-keygen-flags', '-l'),
 254                ('master-attrs', ''),
 255                ('mgf', '${hash}-mgf'),
 256                ('mac', lambda: '%s-hmac/%d' %
 257                          (conf['hash'],
 258                           C.gchashes[conf['hash']].hashsz * 4)),
 259                ('sig', lambda: {'dh': 'dsa', 'ec': 'ecdsa'}[conf['kx']]),
 260                ('sig-fresh', 'always'),
 261                ('sig-genalg', lambda: {'kcdsa': 'dh',
 262                                        'dsa': 'dsa',
 263                                        'rsapkcs1': 'rsa',
 264                                        'rsapss': 'rsa',
 265                                        'ecdsa': 'ec',
 266                                        'eckcdsa': 'ec',
 267                                        'ed25519': 'ed25519',
 268                                        'ed448': 'ed448'}[conf['sig']]),
 269                ('sig-param', lambda: {'dh': '-LS -b3072 -B256',
 270                                       'dsa': '-b3072 -B256',
 271                                       'ec': '-Cnist-p256',
 272                                       'rsa': '-b3072',
 273                                       'ed25519': '',
 274                                       'ed448': ''}[conf['sig-genalg']]),
 275                ('sig-hash', '${hash}'),
 276                ('sig-expire', 'forever'),
 277                ('fingerprint-hash', '${hash}')]:
 278     try:
 279       if k in conf: continue
 280       if type(v) == str:
 281         conf[k] = conf_subst(v)
 282       else:
 283         conf[k] = v()
 284     except KeyError, exc:
 285       if len(exc.args) == 0: raise
 286       conf[k] = '<missing-var %s>' % exc.args[0]
 287
 288 ###--------------------------------------------------------------------------
 289 ### Key-management utilities.
 290
 291 def master_keys():
 292   """
 293   Iterate over the master keys.
 294   """
 295   if not OS.path.exists('master'):
 296     return
 297   for k in C.KeyFile('master').itervalues():
 298     if (k.type != 'tripe-keys-master' or
 299         k.expiredp or
 300         not k.tag.startswith('master-')):
 301       continue #??
 302     yield k
 303
 304 def master_sequence(k):
 305   """
 306   Return the sequence number of the given master key as an integer.
 307
 308   No checking is done that K is really a master key.
 309   """
 310   return int(k.tag[7:])
 311
 312 def max_master_sequence():
 313   """
 314   Find the master key with the highest sequence number and return this
 315   sequence number.
 316   """
 317   seq = -1
 318   for k in master_keys():
 319     q = master_sequence(k)
 320     if q > seq: seq = q
 321   return seq
 322
 323 def seqsubst(x, q):
 324   """
 325   Return the value of the configuration variable X, with <SEQ> replaced by
 326   the value Q.
 327   """
 328   return rx_seq.sub(str(q), conf[x])
 329
 330 ###--------------------------------------------------------------------------
 331 ### Commands: help [COMMAND...]
 332
 333 def version(fp = SYS.stdout):
 334   fp.write('%s, %s version %s\n' % (quis, PACKAGE, VERSION))
 335
 336 def usage(fp):
 337   fp.write('Usage: %s SUBCOMMAND [ARGS...]\n' % quis)
 338
 339 def cmd_help(args):
 340   if len(args) == 0:
 341     version(SYS.stdout)
 342     print
 343     usage(SYS.stdout)
 344     print """
 345 Key management utility for TrIPE.
 346
 347 Options supported:
 348
 349 -h, --help              Show this help message.
 350 -v, --version           Show the version number.
 351 -u, --usage             Show pointlessly short usage string.
 352
 353 Subcommands available:
 354 """
 355     args = commands.keys()
 356     args.sort()
 357   for c in args:
 358     try: func, min, max, help = commands[c]
 359     except KeyError: die("unknown command `%s'" % c)
 360     print '%s%s%s' % (c, help and ' ', help)
 361
 362 ###--------------------------------------------------------------------------
 363 ### Commands: newmaster
 364
 365 def cmd_newmaster(args):
 366   seq = max_master_sequence() + 1
 367   run('''key -kmaster add
 368     -a${sig-genalg} !${sig-param}
 369     -e${sig-expire} !${master-keygen-flags} -tmaster-%d tripe-keys-master
 370     sig=${sig} hash=${sig-hash} !${master-attrs}''' % seq)
 371   run('key -kmaster extract -f-secret repos/master.pub')
 372
 373 ###--------------------------------------------------------------------------
 374 ### Commands: setup
 375
 376 def cmd_setup(args):
 377   OS.mkdir('repos')
 378   run('''key -krepos/param add
 379     -a${kx-param-genalg} !${kx-param}
 380     -eforever -tparam tripe-param
 381     kx-group=${kx} mgf=${mgf} mac=${mac}
 382     bulk=${bulk} cipher=${cipher} hash=${hash} ${kx-attrs}''')
 383   cmd_newmaster(args)
 384
 385 ###--------------------------------------------------------------------------
 386 ### Commands: upload
 387
 388 def cmd_upload(args):
 389
 390   ## Sanitize the repository directory
 391   umask = OS.umask(0); OS.umask(umask)
 392   mode = 0666 & ~umask
 393   for f in OS.listdir('repos'):
 394     ff = OS.path.join('repos', f)
 395     if (f.startswith('master') or f.startswith('peer-')) \
 396            and f.endswith('.old'):
 397       OS.unlink(ff)
 398       continue
 399     OS.chmod(ff, mode)
 400
 401   rmtree('tmp')
 402   OS.mkdir('tmp')
 403   OS.symlink('../repos', 'tmp/repos')
 404   cwd = OS.getcwd()
 405   try:
 406
 407     ## Build the configuration file
 408     seq = max_master_sequence()
 409     v = {'MASTER-SEQUENCE': str(seq),
 410          'HK-MASTER': hexhyphens(fingerprint('repos/master.pub',
 411                                              'master-%d' % seq))}
 412     fin = file('tripe-keys.master')
 413     fout = file('tmp/tripe-keys.conf', 'w')
 414     for line in fin:
 415       fout.write(subst(line, rx_atsubst, v))
 416     fin.close(); fout.close()
 417     SH.copyfile('tmp/tripe-keys.conf', conf_subst('${conf-file}.new'))
 418     commit = [conf['repos-file'], conf['conf-file']]
 419
 420     ## Make and sign the repository archive
 421     OS.chdir('tmp')
 422     run('tar chozf ${repos-file}.new .')
 423     OS.chdir(cwd)
 424     for k in master_keys():
 425       seq = master_sequence(k)
 426       sigfile = seqsubst('sig-file', seq)
 427       run('''catsign -kmaster sign -abdC -kmaster-%d
 428         -o%s.new ${repos-file}.new''' % (seq, sigfile))
 429       commit.append(sigfile)
 430
 431     ## Commit the changes
 432     for base in commit:
 433       new = '%s.new' % base
 434       OS.rename(new, base)
 435
 436     ## Remove files in the base-dir which don't correspond to ones we just
 437     ## committed
 438     allow = {}
 439     basedir = conf['base-dir']
 440     bdl = len(basedir)
 441     for base in commit:
 442       if base.startswith(basedir): allow[base[bdl:]] = 1
 443     for found in OS.listdir(basedir):
 444       if found not in allow: OS.remove(OS.path.join(basedir, found))
 445   finally:
 446     OS.chdir(cwd)
 447     rmtree('tmp')
 448   run('sh -c ${upload-hook}')
 449
 450 ###--------------------------------------------------------------------------
 451 ### Commands: rebuild
 452
 453 def cmd_rebuild(args):
 454   zap('keyring.pub')
 455   for i in OS.listdir('repos'):
 456     if i.startswith('peer-') and i.endswith('.pub'):
 457       run('key -kkeyring.pub merge %s' % OS.path.join('repos', i))
 458
 459 ###--------------------------------------------------------------------------
 460 ### Commands: update
 461
 462 def cmd_update(args):
 463   cwd = OS.getcwd()
 464   rmtree('tmp')
 465   try:
 466
 467     ## Fetch a new distribution
 468     OS.mkdir('tmp')
 469     OS.chdir('tmp')
 470     seq = int(conf['master-sequence'])
 471     run('curl -s -o tripe-keys.tar.gz ${repos-url}')
 472     run('curl -s -o tripe-keys.sig %s' % seqsubst('sig-url', seq))
 473     run('tar xfz tripe-keys.tar.gz')
 474
 475     ## Verify the signature
 476     want = C.bytes(rx_nonalpha.sub('', conf['hk-master']))
 477     got = fingerprint('repos/master.pub', 'master-%d' % seq)
 478     if want != got: raise VerifyError
 479     run('''catsign -krepos/master.pub verify -avC -kmaster-%d
 480       -t${sig-fresh} tripe-keys.sig tripe-keys.tar.gz''' % seq)
 481
 482     ## OK: update our copy
 483     OS.chdir(cwd)
 484     if OS.path.exists('repos'): OS.rename('repos', 'repos.old')
 485     OS.rename('tmp/repos', 'repos')
 486     if not FC.cmp('tmp/tripe-keys.conf', 'tripe-keys.conf', False):
 487       moan('configuration file changed: recommend running another update')
 488       OS.rename('tmp/tripe-keys.conf', 'tripe-keys.conf')
 489     rmtree('repos.old')
 490
 491   finally:
 492     OS.chdir(cwd)
 493     rmtree('tmp')
 494   cmd_rebuild(args)
 495
 496 ###--------------------------------------------------------------------------
 497 ### Commands: generate TAG
 498
 499 def cmd_generate(args):
 500   tag, = args
 501   keyring_pub = 'peer-%s.pub' % tag
 502   zap('keyring'); zap(keyring_pub)
 503   run('key -kkeyring merge repos/param')
 504   run('key -kkeyring add -a${kx-genalg} -pparam -e${kx-expire} -t%s tripe' %
 505       tag)
 506   run('key -kkeyring extract -f-secret %s %s' % (keyring_pub, tag))
 507
 508 ###--------------------------------------------------------------------------
 509 ### Commands: clean
 510
 511 def cmd_clean(args):
 512   rmtree('repos')
 513   rmtree('tmp')
 514   for i in OS.listdir('.'):
 515     r = i
 516     if r.endswith('.old'): r = r[:-4]
 517     if (r == 'master' or r == 'param' or
 518         r == 'keyring' or r == 'keyring.pub' or r.startswith('peer-')):
 519       zap(i)
 520
 521 ###--------------------------------------------------------------------------
 522 ### Commands: check
 523
 524 def check_key(k):
 525   now = T.time()
 526   thresh = int(conf['kx-warn-days']) * 86400
 527   if k.exptime == C.KEXP_FOREVER: return None
 528   elif k.exptime == C.KEXP_EXPIRE: left = -1
 529   else: left = k.exptime - now
 530   if left < 0:
 531     return "key `%s' HAS EXPIRED" % k.tag
 532   elif left < thresh:
 533     if left >= 86400: n, u, uu = left // 86400, 'day', 'days'
 534     else: n, u, uu = left // 3600, 'hour', 'hours'
 535     return "key `%s' EXPIRES in %d %s" % (k.tag, n, n == 1 and u or uu)
 536   else:
 537     return None
 538
 539 def cmd_check(args):
 540   if OS.path.exists('keyring.pub'):
 541     for k in C.KeyFile('keyring.pub').itervalues():
 542       whinge = check_key(k)
 543       if whinge is not None: print whinge
 544   if OS.path.exists('master'):
 545     whinges = []
 546     for k in C.KeyFile('master').itervalues():
 547       whinge = check_key(k)
 548       if whinge is None: break
 549       whinges.append(whinge)
 550     else:
 551       for whinge in whinges: print whinge
 552
 553 ###--------------------------------------------------------------------------
 554 ### Commands: mtu
 555
 556 def mac_tagsz():
 557   macname = conf['mac']
 558   index = macname.rindex('/')
 559   if index == -1: tagsz = C.gcmacs[macname].tagsz
 560   else: tagsz = int(macname[index + 1:])/8
 561   return tagsz
 562
 563 def cmd_mtu(args):
 564   mtu, = (lambda mtu = '1500': (mtu,))(*args)
 565   mtu = int(mtu)
 566
 567   mtu -= 20                             # Minimum IP header
 568   mtu -= 8                              # UDP header
 569   mtu -= 1                              # TrIPE packet type octet
 570
 571   bulk = conf['bulk']
 572
 573   if bulk == 'v0':
 574     blksz = C.gcciphers[conf['cipher']].blksz
 575     mtu -= mac_tagsz()                  # MAC tag
 576     mtu -= 4                            # Sequence number
 577     mtu -= blksz                        # Initialization vector
 578
 579   elif bulk == 'iiv':
 580     mtu -= mac_tagsz()                  # MAC tag
 581     mtu -= 4                            # Sequence number
 582
 583   else:
 584     die("Unknown bulk transform `%s'" % bulk)
 585
 586   print mtu
 587
 588 ###--------------------------------------------------------------------------
 589 ### Main driver.
 590
 591 commands = {'help': (cmd_help, 0, 1, ''),
 592             'newmaster': (cmd_newmaster, 0, 0, ''),
 593             'setup': (cmd_setup, 0, 0, ''),
 594             'upload': (cmd_upload, 0, 0, ''),
 595             'update': (cmd_update, 0, 0, ''),
 596             'clean': (cmd_clean, 0, 0, ''),
 597             'mtu': (cmd_mtu, 0, 1, '[PATH-MTU]'),
 598             'check': (cmd_check, 0, 0, ''),
 599             'generate': (cmd_generate, 1, 1, 'TAG'),
 600             'rebuild': (cmd_rebuild, 0, 0, '')}
 601
 602 def init():
 603   """
 604   Load the appropriate configuration file and set up the configuration
 605   dictionary.
 606   """
 607   for f in ['tripe-keys.master', 'tripe-keys.conf']:
 608     if OS.path.exists(f):
 609       conf_read(f)
 610       break
 611   conf_defaults()
 612
 613 def main(argv):
 614   """
 615   Main program: parse options and dispatch to appropriate command handler.
 616   """
 617   try:
 618     opts, args = O.getopt(argv[1:], 'hvu',
 619                           ['help', 'version', 'usage'])
 620   except O.GetoptError, exc:
 621     moan(exc)
 622     usage(SYS.stderr)
 623     SYS.exit(1)
 624   for o, v in opts:
 625     if o in ('-h', '--help'):
 626       cmd_help([])
 627       SYS.exit(0)
 628     elif o in ('-v', '--version'):
 629       version(SYS.stdout)
 630       SYS.exit(0)
 631     elif o in ('-u', '--usage'):
 632       usage(SYS.stdout)
 633       SYS.exit(0)
 634   if len(argv) < 2:
 635     cmd_help([])
 636   else:
 637     c = argv[1]
 638     try: func, min, max, help = commands[c]
 639     except KeyError: die("unknown command `%s'" % c)
 640     args = argv[2:]
 641     if len(args) < min or (max is not None and len(args) > max):
 642       SYS.stderr.write('Usage: %s %s%s%s\n' % (quis, c, help and ' ', help))
 643       SYS.exit(1)
 644     func(args)
 645
 646 ###----- That's all, folks --------------------------------------------------
 647
 648 if __name__ == '__main__':
 649   init()
 650   main(SYS.argv)