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
 
# 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".
 
 
9
# following functions: "AvahiService.add", "AvahiService.remove",
 
 
10
# "server_state_changed", "entry_group_state_changed", and some lines
 
13
13
# Everything else is
 
14
14
# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
 
 
61
61
from dbus.mainloop.glib import DBusGMainLoop
 
 
64
# Brief description of the operation of this program:
 
 
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.
 
66
76
logger = logging.Logger('mandos')
 
67
77
syslogger = logging.handlers.SysLogHandler\
 
68
 
            (facility = logging.handlers.SysLogHandler.LOG_DAEMON,
 
 
78
            (facility = logging.handlers.SysLogHandler.LOG_DAEMON)
 
70
79
syslogger.setFormatter(logging.Formatter\
 
71
 
                        ('Mandos: %(levelname)s: %(message)s'))
 
 
80
                        ('%(levelname)s: %(message)s'))
 
72
81
logger.addHandler(syslogger)
 
74
 
console = logging.StreamHandler()
 
75
 
console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
 
77
 
logger.addHandler(console)
 
79
85
class AvahiError(Exception):
 
80
86
    def __init__(self, value):
 
 
92
98
class AvahiService(object):
 
93
 
    """An Avahi (Zeroconf) service.
 
95
100
    interface: integer; avahi.IF_UNSPEC or an interface index.
 
96
101
               Used to optionally bind to the specified interface.
 
97
 
    name: string; Example: 'Mandos'
 
98
 
    type: string; Example: '_mandos._tcp'.
 
99
 
                  See <http://www.dns-sd.org/ServiceTypes.html>
 
100
 
    port: integer; what port to announce
 
101
 
    TXT: list of strings; TXT record for the service
 
102
 
    domain: string; Domain to publish on, default to .local if empty.
 
103
 
    host: string; Host to publish records for, default is localhost
 
104
 
    max_renames: integer; maximum number of renames
 
105
 
    rename_count: integer; counter so we only rename after collisions
 
106
 
                  a sensible number of times
 
 
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
 
 
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
 
108
114
    def __init__(self, interface = avahi.IF_UNSPEC, name = None,
 
109
115
                 type = None, port = None, TXT = None, domain = "",
 
110
 
                 host = "", max_renames = 32768):
 
 
116
                 host = "", max_renames = 12):
 
 
117
        """An Avahi (Zeroconf) service. """
 
111
118
        self.interface = interface
 
 
119
126
        self.domain = domain
 
121
128
        self.rename_count = 0
 
122
 
        self.max_renames = max_renames
 
123
129
    def rename(self):
 
124
130
        """Derived from the Avahi example code"""
 
125
131
        if self.rename_count >= self.max_renames:
 
126
132
            logger.critical(u"No suitable service name found after %i"
 
127
133
                            u" retries, exiting.", rename_count)
 
128
134
            raise AvahiServiceError("Too many renames")
 
129
 
        self.name = server.GetAlternativeServiceName(self.name)
 
130
 
        logger.info(u"Changing name to %r ...", str(self.name))
 
131
 
        syslogger.setFormatter(logging.Formatter\
 
132
 
                               ('Mandos (%s): %%(levelname)s:'
 
133
 
                               ' %%(message)s' % self.name))
 
 
135
        name = server.GetAlternativeServiceName(name)
 
 
136
        logger.notice(u"Changing name to %r ...", name)
 
136
139
        self.rename_count += 1
 
 
172
175
    fingerprint: string (40 or 32 hexadecimal digits); used to
 
173
176
                 uniquely identify the client
 
174
177
    secret:    bytestring; sent verbatim (over TLS) to client
 
175
 
    host:      string; available for use by the checker command
 
 
178
    fqdn:      string (FQDN); available for use by the checker command
 
176
179
    created:   datetime.datetime(); object creation, not client host
 
177
180
    last_checked_ok: datetime.datetime() or None if not yet checked OK
 
178
181
    timeout:   datetime.timedelta(); How long from last_checked_ok
 
 
218
221
    interval = property(lambda self: self._interval,
 
220
223
    del _set_interval
 
221
 
    def __init__(self, name = None, stop_hook=None, config={}):
 
222
 
        """Note: the 'checker' key in 'config' sets the
 
223
 
        'checker_command' attribute and *not* the 'checker'
 
 
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.."""
 
226
230
        logger.debug(u"Creating client %r", self.name)
 
227
 
        # Uppercase and remove spaces from fingerprint for later
 
228
 
        # comparison purposes with return value from the fingerprint()
 
230
 
        self.fingerprint = config["fingerprint"].upper()\
 
 
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"")
 
232
235
        logger.debug(u"  Fingerprint: %s", self.fingerprint)
 
233
 
        if "secret" in config:
 
234
 
            self.secret = config["secret"].decode(u"base64")
 
235
 
        elif "secfile" in config:
 
236
 
            sf = open(config["secfile"])
 
 
237
            self.secret = secret.decode(u"base64")
 
237
240
            self.secret = sf.read()
 
240
243
            raise TypeError(u"No secret or secfile for client %s"
 
242
 
        self.host = config.get("host", "")
 
243
246
        self.created = datetime.datetime.now()
 
244
247
        self.last_checked_ok = None
 
245
 
        self.timeout = string_to_delta(config["timeout"])
 
246
 
        self.interval = string_to_delta(config["interval"])
 
 
248
        self.timeout = string_to_delta(timeout)
 
 
249
        self.interval = string_to_delta(interval)
 
247
250
        self.stop_hook = stop_hook
 
248
251
        self.checker = None
 
249
252
        self.checker_initiator_tag = None
 
250
253
        self.stop_initiator_tag = None
 
251
254
        self.checker_callback_tag = None
 
252
 
        self.check_command = config["checker"]
 
 
255
        self.check_command = checker
 
254
257
        """Start this client's checker and timeout hooks"""
 
255
258
        # Schedule a new checker to be started an 'interval' from now,
 
 
268
271
        The possibility that a client might be restarted is left open,
 
269
272
        but not currently used."""
 
270
273
        # If this client doesn't have a secret, it is already stopped.
 
271
 
        if hasattr(self, "secret") and self.secret:
 
272
 
            logger.info(u"Stopping client %s", self.name)
 
 
275
            logger.debug(u"Stopping client %s", self.name)
 
273
276
            self.secret = None
 
 
294
297
        self.checker = None
 
295
298
        if os.WIFEXITED(condition) \
 
296
299
               and (os.WEXITSTATUS(condition) == 0):
 
297
 
            logger.info(u"Checker for %(name)s succeeded",
 
 
300
            logger.debug(u"Checker for %(name)s succeeded",
 
299
302
            self.last_checked_ok = now
 
300
303
            gobject.source_remove(self.stop_initiator_tag)
 
301
304
            self.stop_initiator_tag = gobject.timeout_add\
 
 
305
308
            logger.warning(u"Checker for %(name)s crashed?",
 
308
 
            logger.info(u"Checker for %(name)s failed",
 
 
311
            logger.debug(u"Checker for %(name)s failed",
 
310
313
    def start_checker(self):
 
311
314
        """Start a new checker subprocess if one is not running.
 
312
315
        If a checker already exists, leave it running and do
 
 
335
338
                                 u' %s', self.check_command, error)
 
336
339
                    return True # Try again later
 
338
 
                logger.info(u"Starting checker %r for %s",
 
 
341
                logger.debug(u"Starting checker %r for %s",
 
340
343
                self.checker = subprocess.Popen(command,
 
342
345
                                                shell=True, cwd="/")
 
 
355
358
            self.checker_callback_tag = None
 
356
359
        if getattr(self, "checker", None) is None:
 
358
 
        logger.debug(u"Stopping checker for %(name)s", vars(self))
 
 
361
        logger.debug("Stopping checker for %(name)s", vars(self))
 
360
363
            os.kill(self.checker.pid, signal.SIGTERM)
 
 
394
397
def fingerprint(openpgp):
 
395
398
    "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\
 
396
403
    # New GnuTLS "datum" with the OpenPGP public key
 
397
404
    datum = gnutls.library.types.gnutls_datum_t\
 
398
405
        (ctypes.cast(ctypes.c_char_p(openpgp),
 
399
406
                     ctypes.POINTER(ctypes.c_ubyte)),
 
400
407
         ctypes.c_uint(len(openpgp)))
 
401
 
    # New empty GnuTLS certificate
 
402
 
    crt = gnutls.library.types.gnutls_openpgp_crt_t()
 
403
 
    gnutls.library.functions.gnutls_openpgp_crt_init\
 
405
408
    # Import the OpenPGP public key into the certificate
 
406
 
    gnutls.library.functions.gnutls_openpgp_crt_import\
 
407
 
                    (crt, ctypes.byref(datum),
 
408
 
                     gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
 
 
409
    ret = gnutls.library.functions.gnutls_openpgp_crt_import\
 
 
412
         gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
 
409
413
    # New buffer for the fingerprint
 
410
414
    buffer = ctypes.create_string_buffer(20)
 
411
415
    buffer_length = ctypes.c_size_t()
 
 
427
431
    Note: This will run in its own forked process."""
 
429
433
    def handle(self):
 
430
 
        logger.info(u"TCP connection from: %s",
 
 
434
        logger.debug(u"TCP connection from: %s",
 
431
435
                     unicode(self.client_address))
 
432
436
        session = gnutls.connection.ClientSession\
 
433
437
                  (self.request, gnutls.connection.X509Credentials())
 
435
 
        line = self.request.makefile().readline()
 
436
 
        logger.debug(u"Protocol version: %r", line)
 
438
 
            if int(line.strip().split()[0]) > 1:
 
440
 
        except (ValueError, IndexError, RuntimeError), error:
 
441
 
            logger.error(u"Unknown protocol version: %s", error)
 
444
438
        # Note: gnutls.connection.X509Credentials is really a generic
 
445
439
        # GnuTLS certificate credentials object so long as no X.509
 
446
440
        # keys are added to it.  Therefore, we can use it here despite
 
 
460
454
            session.handshake()
 
461
455
        except gnutls.errors.GNUTLSError, error:
 
462
 
            logger.warning(u"Handshake failed: %s", error)
 
 
456
            logger.debug(u"Handshake failed: %s", error)
 
463
457
            # Do not run session.bye() here: the session is not
 
464
458
            # established.  Just abandon the request.
 
467
461
            fpr = fingerprint(peer_certificate(session))
 
468
462
        except (TypeError, gnutls.errors.GNUTLSError), error:
 
469
 
            logger.warning(u"Bad certificate: %s", error)
 
 
463
            logger.debug(u"Bad certificate: %s", error)
 
472
466
        logger.debug(u"Fingerprint: %s", fpr)
 
 
479
 
            logger.warning(u"Client not found for fingerprint: %s",
 
 
473
            logger.debug(u"Client not found for fingerprint: %s", fpr)
 
483
476
        # Have to check if client.still_valid(), since it is possible
 
484
477
        # that the client timed out while establishing the GnuTLS
 
486
479
        if not client.still_valid():
 
487
 
            logger.warning(u"Client %(name)s is invalid",
 
 
480
            logger.debug(u"Client %(name)s is invalid", vars(client))
 
 
517
509
        """This overrides the normal server_bind() function
 
518
510
        to bind to an interface if one was specified, and also NOT to
 
519
511
        bind to an address or port if they were not specified."""
 
520
 
        if self.settings["interface"]:
 
 
512
        if self.settings["interface"] != avahi.IF_UNSPEC:
 
521
513
            # 25 is from /usr/include/asm-i486/socket.h
 
522
514
            SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
 
 
526
518
                                       self.settings["interface"])
 
527
519
            except socket.error, error:
 
528
520
                if error[0] == errno.EPERM:
 
529
 
                    logger.error(u"No permission to"
 
530
 
                                 u" bind to interface %s",
 
531
 
                                 self.settings["interface"])
 
 
521
                    logger.warning(u"No permission to"
 
 
522
                                   u" bind to interface %s",
 
 
523
                                   self.settings["interface"])
 
534
526
        # Only bind(2) the socket if we really need to.
 
 
537
529
                in6addr_any = "::"
 
538
530
                self.server_address = (in6addr_any,
 
539
531
                                       self.server_address[1])
 
540
 
            elif not self.server_address[1]:
 
 
532
            elif self.server_address[1] is None:
 
541
533
                self.server_address = (self.server_address[0],
 
543
 
#                 if self.settings["interface"]:
 
544
 
#                     self.server_address = (self.server_address[0],
 
550
535
            return super(type(self), self).server_bind()
 
 
587
572
def server_state_changed(state):
 
588
573
    """Derived from the Avahi example code"""
 
589
574
    if state == avahi.SERVER_COLLISION:
 
590
 
        logger.error(u"Server name collision")
 
 
575
        logger.warning(u"Server name collision")
 
592
577
    elif state == avahi.SERVER_RUNNING:
 
 
608
593
        raise AvahiGroupError("State changed: %s", str(error))
 
610
 
def if_nametoindex(interface):
 
 
595
def if_nametoindex(interface, _func=[None]):
 
611
596
    """Call the C function if_nametoindex(), or equivalent"""
 
612
 
    global if_nametoindex
 
 
597
    if _func[0] is not None:
 
 
598
        return _func[0](interface)
 
614
600
        if "ctypes.util" not in sys.modules:
 
615
601
            import ctypes.util
 
616
 
        if_nametoindex = ctypes.cdll.LoadLibrary\
 
617
 
            (ctypes.util.find_library("c")).if_nametoindex
 
 
604
                libc = ctypes.cdll.LoadLibrary\
 
 
605
                       (ctypes.util.find_library("c"))
 
 
606
                func[0] = libc.if_nametoindex
 
 
607
                return _func[0](interface)
 
618
611
    except (OSError, AttributeError):
 
619
612
        if "struct" not in sys.modules:
 
621
614
        if "fcntl" not in sys.modules:
 
623
 
        def if_nametoindex(interface):
 
 
616
        def the_hard_way(interface):
 
624
617
            "Get an interface index the hard way, i.e. using fcntl()"
 
625
618
            SIOCGIFINDEX = 0x8933  # From /usr/include/linux/sockios.h
 
626
619
            s = socket.socket()
 
 
630
623
            interface_index = struct.unpack("I", ifreq[16:20])[0]
 
631
624
            return interface_index
 
632
 
    return if_nametoindex(interface)
 
635
 
def daemon(nochdir = False, noclose = False):
 
 
625
        _func[0] = the_hard_way
 
 
626
        return _func[0](interface)
 
 
629
def daemon(nochdir, noclose):
 
636
630
    """See daemon(3).  Standard BSD Unix function.
 
637
631
    This should really exist as os.daemon, but it doesn't (yet)."""
 
 
659
651
    global main_loop_started
 
660
652
    main_loop_started = False
 
662
 
    parser = OptionParser(version = "%%prog %s" % version)
 
 
654
    parser = OptionParser()
 
663
655
    parser.add_option("-i", "--interface", type="string",
 
664
656
                      metavar="IF", help="Bind to interface IF")
 
665
657
    parser.add_option("-a", "--address", type="string",
 
 
668
660
                      help="Port number to receive requests on")
 
669
661
    parser.add_option("--check", action="store_true", default=False,
 
670
662
                      help="Run self-test")
 
671
 
    parser.add_option("--debug", action="store_true",
 
 
663
    parser.add_option("--debug", action="store_true", default=False,
 
672
664
                      help="Debug mode; run in foreground and log to"
 
674
666
    parser.add_option("--priority", type="string", help="GnuTLS"
 
 
699
691
    # Parse config file for server-global settings
 
700
692
    server_config = ConfigParser.SafeConfigParser(server_defaults)
 
701
693
    del server_defaults
 
702
 
    server_config.read(os.path.join(options.configdir, "mandos.conf"))
 
 
694
    server_config.read(os.path.join(options.configdir, "server.conf"))
 
703
695
    server_section = "server"
 
704
696
    # Convert the SafeConfigParser object to a dict
 
705
697
    server_settings = dict(server_config.items(server_section))
 
 
719
713
    # Now we have our good server settings in "server_settings"
 
721
 
    debug = server_settings["debug"]
 
724
 
        syslogger.setLevel(logging.WARNING)
 
725
 
        console.setLevel(logging.WARNING)
 
727
 
    if server_settings["servicename"] != "Mandos":
 
728
 
        syslogger.setFormatter(logging.Formatter\
 
729
 
                               ('Mandos (%s): %%(levelname)s:'
 
731
 
                                % server_settings["servicename"]))
 
733
715
    # Parse config file with clients
 
734
716
    client_defaults = { "timeout": "1h",
 
735
717
                        "interval": "5m",
 
736
 
                        "checker": "fping -q -- %%(host)s",
 
 
718
                        "checker": "fping -q -- %%(fqdn)s",
 
738
720
    client_config = ConfigParser.SafeConfigParser(client_defaults)
 
739
721
    client_config.read(os.path.join(server_settings["configdir"],
 
 
757
737
            avahi.DBUS_INTERFACE_SERVER )
 
758
738
    # End of Avahi example code
 
 
740
    debug = server_settings["debug"]
 
 
743
        console = logging.StreamHandler()
 
 
744
        # console.setLevel(logging.DEBUG)
 
 
745
        console.setFormatter(logging.Formatter\
 
 
746
                             ('%(levelname)s: %(message)s'))
 
 
747
        logger.addHandler(console)
 
761
751
    def remove_from_clients(client):
 
762
752
        clients.remove(client)
 
764
 
            logger.critical(u"No clients left, exiting")
 
 
754
            logger.debug(u"No clients left, exiting")
 
767
 
    clients.update(Set(Client(name = section,
 
 
757
    clients.update(Set(Client(name=section,
 
768
758
                              stop_hook = remove_from_clients,
 
770
 
                              = dict(client_config.items(section)))
 
 
759
                              **(dict(client_config\
 
771
761
                       for section in client_config.sections()))
 
773
 
        logger.critical(u"No clients defined")
 
777
 
        logger.removeHandler(console)
 
780
 
    pidfilename = "/var/run/mandos/mandos.pid"
 
783
 
        pidfile = open(pidfilename, "w")
 
784
 
        pidfile.write(str(pid) + "\n")
 
788
 
        logger.error(u"Could not write %s file with PID %d",
 
789
 
                     pidfilename, os.getpid())
 
792
767
        "Cleanup function; run on exit"
 
 
820
795
    # Find out what port we got
 
821
796
    service.port = tcp_server.socket.getsockname()[1]
 
822
 
    logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
 
823
 
                u" scope_id %d" % tcp_server.socket.getsockname())
 
 
797
    logger.debug(u"Now listening on port %d", service.port)
 
825
 
    #service.interface = tcp_server.socket.getsockname()[3]
 
 
799
    if not server_settings["interface"]:
 
 
800
        service.interface = if_nametoindex\
 
 
801
                            (server_settings["interface"])
 
828
804
        # From the Avahi example code