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-param', lambda: {'dh': '-LS -b3072 -B256',
 242                                      'ec': '-Cnist-p256'}[conf['kx']]),
 243                ('kx-expire', 'now + 1 year'),
 244                ('kx-warn-days', '28'),
 245                ('cipher', 'rijndael-cbc'),
 246                ('hash', 'sha256'),
 247                ('master-keygen-flags', '-l'),
 248                ('mgf', '${hash}-mgf'),
 249                ('mac', lambda: '%s-hmac/%d' %
 250                          (conf['hash'],
 251                           C.gchashes[conf['hash']].hashsz * 4)),
 252                ('sig', lambda: {'dh': 'dsa', 'ec': 'ecdsa'}[conf['kx']]),
 253                ('sig-fresh', 'always'),
 254                ('sig-genalg', lambda: {'kcdsa': 'dh',
 255                                        'dsa': 'dsa',
 256                                        'rsapkcs1': 'rsa',
 257                                        'rsapss': 'rsa',
 258                                        'ecdsa': 'ec',
 259                                        'eckcdsa': 'ec'}[conf['sig']]),
 260                ('sig-param', lambda: {'dh': '-LS -b3072 -B256',
 261                                       'dsa': '-b3072 -B256',
 262                                       'ec': '-Cnist-p256',
 263                                       'rsa': '-b3072'}[conf['sig-genalg']]),
 264                ('sig-hash', '${hash}'),
 265                ('sig-expire', 'forever'),
 266                ('fingerprint-hash', '${hash}')]:
 267     try:
 268       if k in conf: continue
 269       if type(v) == str:
 270         conf[k] = conf_subst(v)
 271       else:
 272         conf[k] = v()
 273     except KeyError, exc:
 274       if len(exc.args) == 0: raise
 275       conf[k] = '<missing-var %s>' % exc.args[0]
 276
 277 ###--------------------------------------------------------------------------
 278 ### Key-management utilities.
 279
 280 def master_keys():
 281   """
 282   Iterate over the master keys.
 283   """
 284   if not OS.path.exists('master'):
 285     return
 286   for k in C.KeyFile('master').itervalues():
 287     if (k.type != 'tripe-keys-master' or
 288         k.expiredp or
 289         not k.tag.startswith('master-')):
 290       continue #??
 291     yield k
 292
 293 def master_sequence(k):
 294   """
 295   Return the sequence number of the given master key as an integer.
 296
 297   No checking is done that K is really a master key.
 298   """
 299   return int(k.tag[7:])
 300
 301 def max_master_sequence():
 302   """
 303   Find the master key with the highest sequence number and return this
 304   sequence number.
 305   """
 306   seq = -1
 307   for k in master_keys():
 308     q = master_sequence(k)
 309     if q > seq: seq = q
 310   return seq
 311
 312 def seqsubst(x, q):
 313   """
 314   Return the value of the configuration variable X, with <SEQ> replaced by
 315   the value Q.
 316   """
 317   return rx_seq.sub(str(q), conf[x])
 318
 319 ###--------------------------------------------------------------------------
 320 ### Commands: help [COMMAND...]
 321
 322 def version(fp = SYS.stdout):
 323   fp.write('%s, %s version %s\n' % (quis, PACKAGE, VERSION))
 324
 325 def usage(fp):
 326   fp.write('Usage: %s SUBCOMMAND [ARGS...]\n' % quis)
 327
 328 def cmd_help(args):
 329   if len(args) == 0:
 330     version(SYS.stdout)
 331     print
 332     usage(SYS.stdout)
 333     print """
 334 Key management utility for TrIPE.
 335
 336 Options supported:
 337
 338 -h, --help              Show this help message.
 339 -v, --version           Show the version number.
 340 -u, --usage             Show pointlessly short usage string.
 341
 342 Subcommands available:
 343 """
 344     args = commands.keys()
 345     args.sort()
 346   for c in args:
 347     func, min, max, help = commands[c]
 348     print '%s %s' % (c, help)
 349
 350 ###--------------------------------------------------------------------------
 351 ### Commands: newmaster
 352
 353 def cmd_newmaster(args):
 354   seq = max_master_sequence() + 1
 355   run('''key -kmaster add
 356     -a${sig-genalg} !${sig-param}
 357     -e${sig-expire} !${master-keygen-flags} -tmaster-%d tripe-keys-master
 358     sig=${sig} hash=${sig-hash}''' % seq)
 359   run('key -kmaster extract -f-secret repos/master.pub')
 360
 361 ###--------------------------------------------------------------------------
 362 ### Commands: setup
 363
 364 def cmd_setup(args):
 365   OS.mkdir('repos')
 366   run('''key -krepos/param add
 367     -a${kx}-param !${kx-param}
 368     -eforever -tparam tripe-param
 369     kx-group=${kx} cipher=${cipher} hash=${hash} mac=${mac} mgf=${mgf}''')
 370   cmd_newmaster(args)
 371
 372 ###--------------------------------------------------------------------------
 373 ### Commands: upload
 374
 375 def cmd_upload(args):
 376
 377   ## Sanitize the repository directory
 378   umask = OS.umask(0); OS.umask(umask)
 379   mode = 0666 & ~umask
 380   for f in OS.listdir('repos'):
 381     ff = OS.path.join('repos', f)
 382     if (f.startswith('master') or f.startswith('peer-')) \
 383            and f.endswith('.old'):
 384       OS.unlink(ff)
 385       continue
 386     OS.chmod(ff, mode)
 387
 388   rmtree('tmp')
 389   OS.mkdir('tmp')
 390   OS.symlink('../repos', 'tmp/repos')
 391   cwd = OS.getcwd()
 392   try:
 393
 394     ## Build the configuration file
 395     seq = max_master_sequence()
 396     v = {'MASTER-SEQUENCE': str(seq),
 397          'HK-MASTER': hexhyphens(fingerprint('repos/master.pub',
 398                                              'master-%d' % seq))}
 399     fin = file('tripe-keys.master')
 400     fout = file('tmp/tripe-keys.conf', 'w')
 401     for line in fin:
 402       fout.write(subst(line, rx_atsubst, v))
 403     fin.close(); fout.close()
 404     SH.copyfile('tmp/tripe-keys.conf', conf_subst('${conf-file}.new'))
 405     commit = [conf['repos-file'], conf['conf-file']]
 406
 407     ## Make and sign the repository archive
 408     OS.chdir('tmp')
 409     run('tar chozf ${repos-file}.new .')
 410     OS.chdir(cwd)
 411     for k in master_keys():
 412       seq = master_sequence(k)
 413       sigfile = seqsubst('sig-file', seq)
 414       run('''catsign -kmaster sign -abdC -kmaster-%d
 415         -o%s.new ${repos-file}.new''' % (seq, sigfile))
 416       commit.append(sigfile)
 417
 418     ## Commit the changes
 419     for base in commit:
 420       new = '%s.new' % base
 421       OS.rename(new, base)
 422   finally:
 423     OS.chdir(cwd)
 424     rmtree('tmp')
 425   run('sh -c ${upload-hook}')
 426
 427 ###--------------------------------------------------------------------------
 428 ### Commands: rebuild
 429
 430 def cmd_rebuild(args):
 431   zap('keyring.pub')
 432   for i in OS.listdir('repos'):
 433     if i.startswith('peer-') and i.endswith('.pub'):
 434       run('key -kkeyring.pub merge %s' % OS.path.join('repos', i))
 435
 436 ###--------------------------------------------------------------------------
 437 ### Commands: update
 438
 439 def cmd_update(args):
 440   cwd = OS.getcwd()
 441   rmtree('tmp')
 442   try:
 443
 444     ## Fetch a new distribution
 445     OS.mkdir('tmp')
 446     OS.chdir('tmp')
 447     seq = int(conf['master-sequence'])
 448     run('curl -s -o tripe-keys.tar.gz ${repos-url}')
 449     run('curl -s -o tripe-keys.sig %s' % seqsubst('sig-url', seq))
 450     run('tar xfz tripe-keys.tar.gz')
 451
 452     ## Verify the signature
 453     want = C.bytes(rx_nonalpha.sub('', conf['hk-master']))
 454     got = fingerprint('repos/master.pub', 'master-%d' % seq)
 455     if want != got: raise VerifyError
 456     run('''catsign -krepos/master.pub verify -avC -kmaster-%d
 457       -t${sig-fresh} tripe-keys.sig tripe-keys.tar.gz''' % seq)
 458
 459     ## OK: update our copy
 460     OS.chdir(cwd)
 461     if OS.path.exists('repos'): OS.rename('repos', 'repos.old')
 462     OS.rename('tmp/repos', 'repos')
 463     if not FC.cmp('tmp/tripe-keys.conf', 'tripe-keys.conf'):
 464       moan('configuration file changed: recommend running another update')
 465       OS.rename('tmp/tripe-keys.conf', 'tripe-keys.conf')
 466     rmtree('repos.old')
 467
 468   finally:
 469     OS.chdir(cwd)
 470     rmtree('tmp')
 471   cmd_rebuild(args)
 472
 473 ###--------------------------------------------------------------------------
 474 ### Commands: generate TAG
 475
 476 def cmd_generate(args):
 477   tag, = args
 478   keyring_pub = 'peer-%s.pub' % tag
 479   zap('keyring'); zap(keyring_pub)
 480   run('key -kkeyring merge repos/param')
 481   run('key -kkeyring add -a${kx} -pparam -e${kx-expire} -t%s tripe' %
 482       tag)
 483   run('key -kkeyring extract -f-secret %s %s' % (keyring_pub, tag))
 484
 485 ###--------------------------------------------------------------------------
 486 ### Commands: clean
 487
 488 def cmd_clean(args):
 489   rmtree('repos')
 490   rmtree('tmp')
 491   for i in OS.listdir('.'):
 492     r = i
 493     if r.endswith('.old'): r = r[:-4]
 494     if (r == 'master' or r == 'param' or
 495         r == 'keyring' or r == 'keyring.pub' or r.startswith('peer-')):
 496       zap(i)
 497
 498 ###--------------------------------------------------------------------------
 499 ### Commands: check
 500
 501 def check_key(k):
 502   now = T.time()
 503   thresh = int(conf['kx-warn-days']) * 86400
 504   if k.exptime == C.KEXP_FOREVER: return None
 505   elif k.exptime == C.KEXP_EXPIRE: left = -1
 506   else: left = k.exptime - now
 507   if left < 0:
 508     return "key `%s' HAS EXPIRED" % k.tag
 509   elif left < thresh:
 510     if left >= 86400: n, u, uu = left // 86400, 'day', 'days'
 511     else: n, u, uu = left // 3600, 'hour', 'hours'
 512     return "key `%s' EXPIRES in %d %s" % (k.tag, n, n == 1 and u or uu)
 513   else:
 514     return None
 515
 516 def cmd_check(args):
 517   if OS.path.exists('keyring.pub'):
 518     for k in C.KeyFile('keyring.pub').itervalues():
 519       whinge = check_key(k)
 520       if whinge is not None: print whinge
 521   if OS.path.exists('master'):
 522     whinges = []
 523     for k in C.KeyFile('master').itervalues():
 524       whinge = check_key(k)
 525       if whinge is None: break
 526       whinges.append(whinge)
 527     else:
 528       for whinge in whinges: print whinge
 529
 530 ###--------------------------------------------------------------------------
 531 ### Commands: mtu
 532
 533 def cmd_mtu(args):
 534   mtu, = (lambda mtu = '1500': (mtu,))(*args)
 535   mtu = int(mtu)
 536
 537   blksz = C.gcciphers[conf['cipher']].blksz
 538
 539   index = conf['mac'].find('/')
 540   if index == -1:
 541     tagsz = C.gcmacs[conf['mac']].tagsz
 542   else:
 543     tagsz = int(conf['mac'][index + 1:])/8
 544
 545   mtu -= 20                             # Minimum IP header
 546   mtu -= 8                              # UDP header
 547   mtu -= 1                              # TrIPE packet type octet
 548   mtu -= tagsz                          # MAC tag
 549   mtu -= 4                              # Sequence number
 550   mtu -= blksz                          # Initialization vector
 551
 552   print mtu
 553
 554 ###--------------------------------------------------------------------------
 555 ### Main driver.
 556
 557 ## Exceptions.
 558 class UsageError (Exception): pass
 559
 560 commands = {'help': (cmd_help, 0, 1, ''),
 561             'newmaster': (cmd_newmaster, 0, 0, ''),
 562             'setup': (cmd_setup, 0, 0, ''),
 563             'upload': (cmd_upload, 0, 0, ''),
 564             'update': (cmd_update, 0, 0, ''),
 565             'clean': (cmd_clean, 0, 0, ''),
 566             'mtu': (cmd_mtu, 0, 1, '[PATH-MTU]'),
 567             'check': (cmd_check, 0, 0, ''),
 568             'generate': (cmd_generate, 1, 1, 'TAG'),
 569             'rebuild': (cmd_rebuild, 0, 0, '')}
 570
 571 def init():
 572   """
 573   Load the appropriate configuration file and set up the configuration
 574   dictionary.
 575   """
 576   for f in ['tripe-keys.master', 'tripe-keys.conf']:
 577     if OS.path.exists(f):
 578       conf_read(f)
 579       break
 580   conf_defaults()
 581
 582 def main(argv):
 583   """
 584   Main program: parse options and dispatch to appropriate command handler.
 585   """
 586   try:
 587     opts, args = O.getopt(argv[1:], 'hvu',
 588                           ['help', 'version', 'usage'])
 589   except O.GetoptError, exc:
 590     moan(exc)
 591     usage(SYS.stderr)
 592     SYS.exit(1)
 593   for o, v in opts:
 594     if o in ('-h', '--help'):
 595       cmd_help([])
 596       SYS.exit(0)
 597     elif o in ('-v', '--version'):
 598       version(SYS.stdout)
 599       SYS.exit(0)
 600     elif o in ('-u', '--usage'):
 601       usage(SYS.stdout)
 602       SYS.exit(0)
 603   if len(argv) < 2:
 604     cmd_help([])
 605   else:
 606     c = argv[1]
 607     func, min, max, help = commands[c]
 608     args = argv[2:]
 609     if len(args) < min or (max > 0 and len(args) > max):
 610       raise UsageError, (c, help)
 611     func(args)
 612
 613 ###----- That's all, folks --------------------------------------------------
 614
 615 if __name__ == '__main__':
 616   init()
 617   main(SYS.argv)