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mandos
6
6
# This program is partly derived from an example program for an Avahi
7
7
# service publisher, downloaded from
8
8
# <http://avahi.org/wiki/PythonPublishExample>.  This includes the
9
 
# following functions: "AvahiService.add", "AvahiService.remove",
10
 
# "server_state_changed", "entry_group_state_changed", and some lines
11
 
# in "main".
 
9
# methods "add" and "remove" in the "AvahiService" class, the
 
10
# "server_state_changed" and "entry_group_state_changed" functions,
 
11
# and some lines in "main".
12
12
# 
13
13
# Everything else is
14
14
# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
61
61
from dbus.mainloop.glib import DBusGMainLoop
62
62
import ctypes
63
63
 
64
 
# Brief description of the operation of this program:
65
 
# 
66
 
# This server announces itself as a Zeroconf service.  Connecting
67
 
# clients use the TLS protocol, with the unusual quirk that this
68
 
# server program acts as a TLS "client" while a connecting client acts
69
 
# as a TLS "server".  The client (acting as a TLS "server") must
70
 
# supply an OpenPGP certificate, and the fingerprint of this
71
 
# certificate is used by this server to look up (in a list read from a
72
 
# file at start time) which binary blob to give the client.  No other
73
 
# authentication or authorization is done by this server.
74
 
 
75
64
 
76
65
logger = logging.Logger('mandos')
77
66
syslogger = logging.handlers.SysLogHandler\
96
85
 
97
86
 
98
87
class AvahiService(object):
99
 
    """
 
88
    """An Avahi (Zeroconf) service.
 
89
    Attributes:
100
90
    interface: integer; avahi.IF_UNSPEC or an interface index.
101
91
               Used to optionally bind to the specified interface.
102
 
    name = string; Example: "Mandos"
103
 
    type = string; Example: "_mandos._tcp".
104
 
                   See <http://www.dns-sd.org/ServiceTypes.html>
105
 
    port = integer; what port to announce
106
 
    TXT = list of strings; TXT record for the service
107
 
    domain = string; Domain to publish on, default to .local if empty.
108
 
    host = string; Host to publish records for, default to localhost
109
 
                   if empty.
110
 
    max_renames = integer; maximum number of renames
111
 
    rename_count = integer; counter so we only rename after collisions
112
 
                   a sensible number of times
 
92
    name: string; Example: 'Mandos'
 
93
    type: string; Example: '_mandos._tcp'.
 
94
                  See <http://www.dns-sd.org/ServiceTypes.html>
 
95
    port: integer; what port to announce
 
96
    TXT: list of strings; TXT record for the service
 
97
    domain: string; Domain to publish on, default to .local if empty.
 
98
    host: string; Host to publish records for, default is localhost
 
99
    max_renames: integer; maximum number of renames
 
100
    rename_count: integer; counter so we only rename after collisions
 
101
                  a sensible number of times
113
102
    """
114
103
    def __init__(self, interface = avahi.IF_UNSPEC, name = None,
115
104
                 type = None, port = None, TXT = None, domain = "",
116
105
                 host = "", max_renames = 12):
117
 
        """An Avahi (Zeroconf) service. """
118
106
        self.interface = interface
119
107
        self.name = name
120
108
        self.type = type
133
121
                            u" retries, exiting.", rename_count)
134
122
            raise AvahiServiceError("Too many renames")
135
123
        name = server.GetAlternativeServiceName(name)
136
 
        logger.notice(u"Changing name to %r ...", name)
 
124
        logger.error(u"Changing name to %r ...", name)
137
125
        self.remove()
138
126
        self.add()
139
127
        self.rename_count += 1
221
209
    interval = property(lambda self: self._interval,
222
210
                        _set_interval)
223
211
    del _set_interval
224
 
    def __init__(self, name=None, stop_hook=None, fingerprint=None,
225
 
                 secret=None, secfile=None, fqdn=None, timeout=None,
226
 
                 interval=-1, checker=None):
227
 
        """Note: the 'checker' argument sets the 'checker_command'
228
 
        attribute and not the 'checker' attribute.."""
 
212
    def __init__(self, name = None, stop_hook=None, config={}):
 
213
        """Note: the 'checker' key in 'config' sets the
 
214
        'checker_command' attribute and *not* the 'checker'
 
215
        attribute."""
229
216
        self.name = name
230
217
        logger.debug(u"Creating client %r", self.name)
231
 
        # Uppercase and remove spaces from fingerprint
232
 
        # for later comparison purposes with return value of
233
 
        # the fingerprint() function
234
 
        self.fingerprint = fingerprint.upper().replace(u" ", u"")
 
218
        # Uppercase and remove spaces from fingerprint for later
 
219
        # comparison purposes with return value from the fingerprint()
 
220
        # function
 
221
        self.fingerprint = config["fingerprint"].upper()\
 
222
                           .replace(u" ", u"")
235
223
        logger.debug(u"  Fingerprint: %s", self.fingerprint)
236
 
        if secret:
237
 
            self.secret = secret.decode(u"base64")
238
 
        elif secfile:
239
 
            sf = open(secfile)
 
224
        if "secret" in config:
 
225
            self.secret = config["secret"].decode(u"base64")
 
226
        elif "secfile" in config:
 
227
            sf = open(config["secfile"])
240
228
            self.secret = sf.read()
241
229
            sf.close()
242
230
        else:
243
231
            raise TypeError(u"No secret or secfile for client %s"
244
232
                            % self.name)
245
 
        self.fqdn = fqdn
 
233
        self.fqdn = config.get("fqdn", "")
246
234
        self.created = datetime.datetime.now()
247
235
        self.last_checked_ok = None
248
 
        self.timeout = string_to_delta(timeout)
249
 
        self.interval = string_to_delta(interval)
 
236
        self.timeout = string_to_delta(config["timeout"])
 
237
        self.interval = string_to_delta(config["interval"])
250
238
        self.stop_hook = stop_hook
251
239
        self.checker = None
252
240
        self.checker_initiator_tag = None
253
241
        self.stop_initiator_tag = None
254
242
        self.checker_callback_tag = None
255
 
        self.check_command = checker
 
243
        self.check_command = config["checker"]
256
244
    def start(self):
257
245
        """Start this client's checker and timeout hooks"""
258
246
        # Schedule a new checker to be started an 'interval' from now,
272
260
        but not currently used."""
273
261
        # If this client doesn't have a secret, it is already stopped.
274
262
        if self.secret:
275
 
            logger.debug(u"Stopping client %s", self.name)
 
263
            logger.info(u"Stopping client %s", self.name)
276
264
            self.secret = None
277
265
        else:
278
266
            return False
297
285
        self.checker = None
298
286
        if os.WIFEXITED(condition) \
299
287
               and (os.WEXITSTATUS(condition) == 0):
300
 
            logger.debug(u"Checker for %(name)s succeeded",
301
 
                         vars(self))
 
288
            logger.info(u"Checker for %(name)s succeeded",
 
289
                        vars(self))
302
290
            self.last_checked_ok = now
303
291
            gobject.source_remove(self.stop_initiator_tag)
304
292
            self.stop_initiator_tag = gobject.timeout_add\
308
296
            logger.warning(u"Checker for %(name)s crashed?",
309
297
                           vars(self))
310
298
        else:
311
 
            logger.debug(u"Checker for %(name)s failed",
312
 
                         vars(self))
 
299
            logger.info(u"Checker for %(name)s failed",
 
300
                        vars(self))
313
301
    def start_checker(self):
314
302
        """Start a new checker subprocess if one is not running.
315
303
        If a checker already exists, leave it running and do
338
326
                                 u' %s', self.check_command, error)
339
327
                    return True # Try again later
340
328
            try:
341
 
                logger.debug(u"Starting checker %r for %s",
342
 
                             command, self.name)
 
329
                logger.info(u"Starting checker %r for %s",
 
330
                            command, self.name)
343
331
                self.checker = subprocess.Popen(command,
344
332
                                                close_fds=True,
345
333
                                                shell=True, cwd="/")
396
384
 
397
385
def fingerprint(openpgp):
398
386
    "Convert an OpenPGP bytestring to a hexdigit fingerprint string"
399
 
    # New empty GnuTLS certificate
400
 
    crt = gnutls.library.types.gnutls_openpgp_crt_t()
401
 
    gnutls.library.functions.gnutls_openpgp_crt_init\
402
 
        (ctypes.byref(crt))
403
387
    # New GnuTLS "datum" with the OpenPGP public key
404
388
    datum = gnutls.library.types.gnutls_datum_t\
405
389
        (ctypes.cast(ctypes.c_char_p(openpgp),
406
390
                     ctypes.POINTER(ctypes.c_ubyte)),
407
391
         ctypes.c_uint(len(openpgp)))
 
392
    # New empty GnuTLS certificate
 
393
    crt = gnutls.library.types.gnutls_openpgp_crt_t()
 
394
    gnutls.library.functions.gnutls_openpgp_crt_init\
 
395
        (ctypes.byref(crt))
408
396
    # Import the OpenPGP public key into the certificate
409
 
    ret = gnutls.library.functions.gnutls_openpgp_crt_import\
410
 
        (crt,
411
 
         ctypes.byref(datum),
412
 
         gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
 
397
    gnutls.library.functions.gnutls_openpgp_crt_import\
 
398
                    (crt, ctypes.byref(datum),
 
399
                     gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
413
400
    # New buffer for the fingerprint
414
401
    buffer = ctypes.create_string_buffer(20)
415
402
    buffer_length = ctypes.c_size_t()
431
418
    Note: This will run in its own forked process."""
432
419
    
433
420
    def handle(self):
434
 
        logger.debug(u"TCP connection from: %s",
 
421
        logger.info(u"TCP connection from: %s",
435
422
                     unicode(self.client_address))
436
423
        session = gnutls.connection.ClientSession\
437
424
                  (self.request, gnutls.connection.X509Credentials())
 
425
        
 
426
        line = self.request.makefile().readline()
 
427
        logger.debug(u"Protocol version: %r", line)
 
428
        try:
 
429
            if int(line.strip().split()[0]) > 1:
 
430
                raise RuntimeError
 
431
        except (ValueError, IndexError, RuntimeError), error:
 
432
            logger.error(u"Unknown protocol version: %s", error)
 
433
            return
 
434
        
438
435
        # Note: gnutls.connection.X509Credentials is really a generic
439
436
        # GnuTLS certificate credentials object so long as no X.509
440
437
        # keys are added to it.  Therefore, we can use it here despite
453
450
        try:
454
451
            session.handshake()
455
452
        except gnutls.errors.GNUTLSError, error:
456
 
            logger.debug(u"Handshake failed: %s", error)
 
453
            logger.warning(u"Handshake failed: %s", error)
457
454
            # Do not run session.bye() here: the session is not
458
455
            # established.  Just abandon the request.
459
456
            return
460
457
        try:
461
458
            fpr = fingerprint(peer_certificate(session))
462
459
        except (TypeError, gnutls.errors.GNUTLSError), error:
463
 
            logger.debug(u"Bad certificate: %s", error)
 
460
            logger.warning(u"Bad certificate: %s", error)
464
461
            session.bye()
465
462
            return
466
463
        logger.debug(u"Fingerprint: %s", fpr)
470
467
                client = c
471
468
                break
472
469
        if not client:
473
 
            logger.debug(u"Client not found for fingerprint: %s", fpr)
 
470
            logger.warning(u"Client not found for fingerprint: %s",
 
471
                           fpr)
474
472
            session.bye()
475
473
            return
476
474
        # Have to check if client.still_valid(), since it is possible
477
475
        # that the client timed out while establishing the GnuTLS
478
476
        # session.
479
477
        if not client.still_valid():
480
 
            logger.debug(u"Client %(name)s is invalid", vars(client))
 
478
            logger.warning(u"Client %(name)s is invalid",
 
479
                           vars(client))
481
480
            session.bye()
482
481
            return
483
482
        sent_size = 0
518
517
                                       self.settings["interface"])
519
518
            except socket.error, error:
520
519
                if error[0] == errno.EPERM:
521
 
                    logger.warning(u"No permission to"
522
 
                                   u" bind to interface %s",
523
 
                                   self.settings["interface"])
 
520
                    logger.error(u"No permission to"
 
521
                                 u" bind to interface %s",
 
522
                                 self.settings["interface"])
524
523
                else:
525
524
                    raise error
526
525
        # Only bind(2) the socket if we really need to.
572
571
def server_state_changed(state):
573
572
    """Derived from the Avahi example code"""
574
573
    if state == avahi.SERVER_COLLISION:
575
 
        logger.warning(u"Server name collision")
 
574
        logger.error(u"Server name collision")
576
575
        service.remove()
577
576
    elif state == avahi.SERVER_RUNNING:
578
577
        service.add()
592
591
                        unicode(error))
593
592
        raise AvahiGroupError("State changed: %s", str(error))
594
593
 
595
 
def if_nametoindex(interface, _func=[None]):
 
594
def if_nametoindex(interface):
596
595
    """Call the C function if_nametoindex(), or equivalent"""
597
 
    if _func[0] is not None:
598
 
        return _func[0](interface)
 
596
    global if_nametoindex
599
597
    try:
600
598
        if "ctypes.util" not in sys.modules:
601
599
            import ctypes.util
602
 
        while True:
603
 
            try:
604
 
                libc = ctypes.cdll.LoadLibrary\
605
 
                       (ctypes.util.find_library("c"))
606
 
                _func[0] = libc.if_nametoindex
607
 
                return _func[0](interface)
608
 
            except IOError, e:
609
 
                if e != errno.EINTR:
610
 
                    raise
 
600
        if_nametoindex = ctypes.cdll.LoadLibrary\
 
601
            (ctypes.util.find_library("c")).if_nametoindex
611
602
    except (OSError, AttributeError):
612
603
        if "struct" not in sys.modules:
613
604
            import struct
614
605
        if "fcntl" not in sys.modules:
615
606
            import fcntl
616
 
        def the_hard_way(interface):
 
607
        def if_nametoindex(interface):
617
608
            "Get an interface index the hard way, i.e. using fcntl()"
618
609
            SIOCGIFINDEX = 0x8933  # From /usr/include/linux/sockios.h
619
610
            s = socket.socket()
622
613
            s.close()
623
614
            interface_index = struct.unpack("I", ifreq[16:20])[0]
624
615
            return interface_index
625
 
        _func[0] = the_hard_way
626
 
        return _func[0](interface)
627
 
 
628
 
 
629
 
def daemon(nochdir, noclose):
 
616
    return if_nametoindex(interface)
 
617
 
 
618
 
 
619
def daemon(nochdir = False, noclose = False):
630
620
    """See daemon(3).  Standard BSD Unix function.
631
621
    This should really exist as os.daemon, but it doesn't (yet)."""
632
622
    if os.fork():
634
624
    os.setsid()
635
625
    if not nochdir:
636
626
        os.chdir("/")
 
627
    if os.fork():
 
628
        sys.exit()
637
629
    if not noclose:
638
630
        # Close all standard open file descriptors
639
631
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
691
683
    # Parse config file for server-global settings
692
684
    server_config = ConfigParser.SafeConfigParser(server_defaults)
693
685
    del server_defaults
694
 
    server_config.read(os.path.join(options.configdir, "server.conf"))
 
686
    server_config.read(os.path.join(options.configdir, "mandos.conf"))
695
687
    server_section = "server"
696
688
    # Convert the SafeConfigParser object to a dict
697
689
    server_settings = dict(server_config.items(server_section))
751
743
    def remove_from_clients(client):
752
744
        clients.remove(client)
753
745
        if not clients:
754
 
            logger.debug(u"No clients left, exiting")
 
746
            logger.critical(u"No clients left, exiting")
755
747
            sys.exit()
756
748
    
757
 
    clients.update(Set(Client(name=section,
 
749
    clients.update(Set(Client(name = section,
758
750
                              stop_hook = remove_from_clients,
759
 
                              **(dict(client_config\
760
 
                                      .items(section))))
 
751
                              config
 
752
                              = dict(client_config.items(section)))
761
753
                       for section in client_config.sections()))
762
754
    
763
755
    if not debug:
764
 
        daemon(False, False)
 
756
        daemon()
765
757
    
766
758
    def cleanup():
767
759
        "Cleanup function; run on exit"
794
786
                                clients=clients)
795
787
    # Find out what port we got
796
788
    service.port = tcp_server.socket.getsockname()[1]
797
 
    logger.debug(u"Now listening on address %r, port %d, flowinfo %d,"
798
 
                 u" scope_id %d" % tcp_server.socket.getsockname())
 
789
    logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
 
790
                u" scope_id %d" % tcp_server.socket.getsockname())
799
791
    
800
792
    #service.interface = tcp_server.socket.getsockname()[3]
801
793