/mandos/release

To get this branch, use:
bzr branch http://bzr.recompile.se/loggerhead/mandos/release

« back to all changes in this revision

Viewing changes to server.py

  • Committer: Teddy Hogeborn
  • Date: 2008-07-31 19:48:05 UTC
  • Revision ID: teddy@fukt.bsnet.se-20080731194805-mseis21dxwrdfqhk
* plugins.d/mandosclient.c (start_mandos_communication): Changed
                                                        "if_index" to
                                                        be of type
                                                        "AvahiIfIndex".
                                                        All callers
                                                        changed.
 (main): Add default values to "interface" and "if_index".  Only
         change if_index from default if "interface" was given.

* server.py (IPv6_TCPServer.server_bind): Bug fix: test if interface
                                          is empty, not if equal to
                                          avahi.IF_UNSPEC.
  (if_nametoindex): Bug fix; typo: assign to _func[0], not func[0].
  (main): Bug fix: Do not set service.interface unless the interface
          setting has been given.

Show diffs side-by-side

added added

removed removed

Lines of Context:
server.py
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
 
11
# 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
 
64
75
 
65
76
logger = logging.Logger('mandos')
66
77
syslogger = logging.handlers.SysLogHandler\
67
 
            (facility = logging.handlers.SysLogHandler.LOG_DAEMON,
68
 
             address = "/dev/log")
 
78
            (facility = logging.handlers.SysLogHandler.LOG_DAEMON)
69
79
syslogger.setFormatter(logging.Formatter\
70
 
                        ('Mandos: %(levelname)s: %(message)s'))
 
80
                        ('%(levelname)s: %(message)s'))
71
81
logger.addHandler(syslogger)
 
82
del syslogger
72
83
 
73
84
 
74
85
class AvahiError(Exception):
85
96
 
86
97
 
87
98
class AvahiService(object):
88
 
    """An Avahi (Zeroconf) service.
89
 
    Attributes:
 
99
    """
90
100
    interface: integer; avahi.IF_UNSPEC or an interface index.
91
101
               Used to optionally bind to the specified interface.
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
 
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
102
113
    """
103
114
    def __init__(self, interface = avahi.IF_UNSPEC, name = None,
104
115
                 type = None, port = None, TXT = None, domain = "",
105
 
                 host = "", max_renames = 32768):
 
116
                 host = "", max_renames = 12):
 
117
        """An Avahi (Zeroconf) service. """
106
118
        self.interface = interface
107
119
        self.name = name
108
120
        self.type = type
121
133
                            u" retries, exiting.", rename_count)
122
134
            raise AvahiServiceError("Too many renames")
123
135
        name = server.GetAlternativeServiceName(name)
124
 
        logger.error(u"Changing name to %r ...", name)
125
 
        syslogger.setFormatter(logging.Formatter\
126
 
                               ('Mandos (%s): %%(levelname)s:'
127
 
                               ' %%(message)s' % name))
 
136
        logger.notice(u"Changing name to %r ...", name)
128
137
        self.remove()
129
138
        self.add()
130
139
        self.rename_count += 1
166
175
    fingerprint: string (40 or 32 hexadecimal digits); used to
167
176
                 uniquely identify the client
168
177
    secret:    bytestring; sent verbatim (over TLS) to client
169
 
    host:      string; available for use by the checker command
 
178
    fqdn:      string (FQDN); available for use by the checker command
170
179
    created:   datetime.datetime(); object creation, not client host
171
180
    last_checked_ok: datetime.datetime() or None if not yet checked OK
172
181
    timeout:   datetime.timedelta(); How long from last_checked_ok
212
221
    interval = property(lambda self: self._interval,
213
222
                        _set_interval)
214
223
    del _set_interval
215
 
    def __init__(self, name = None, stop_hook=None, config={}):
216
 
        """Note: the 'checker' key in 'config' sets the
217
 
        'checker_command' attribute and *not* the 'checker'
218
 
        attribute."""
 
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.."""
219
229
        self.name = name
220
230
        logger.debug(u"Creating client %r", self.name)
221
 
        # Uppercase and remove spaces from fingerprint for later
222
 
        # comparison purposes with return value from the fingerprint()
223
 
        # function
224
 
        self.fingerprint = config["fingerprint"].upper()\
225
 
                           .replace(u" ", u"")
 
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"")
226
235
        logger.debug(u"  Fingerprint: %s", self.fingerprint)
227
 
        if "secret" in config:
228
 
            self.secret = config["secret"].decode(u"base64")
229
 
        elif "secfile" in config:
230
 
            sf = open(config["secfile"])
 
236
        if secret:
 
237
            self.secret = secret.decode(u"base64")
 
238
        elif secfile:
 
239
            sf = open(secfile)
231
240
            self.secret = sf.read()
232
241
            sf.close()
233
242
        else:
234
243
            raise TypeError(u"No secret or secfile for client %s"
235
244
                            % self.name)
236
 
        self.host = config.get("host", "")
 
245
        self.fqdn = fqdn
237
246
        self.created = datetime.datetime.now()
238
247
        self.last_checked_ok = None
239
 
        self.timeout = string_to_delta(config["timeout"])
240
 
        self.interval = string_to_delta(config["interval"])
 
248
        self.timeout = string_to_delta(timeout)
 
249
        self.interval = string_to_delta(interval)
241
250
        self.stop_hook = stop_hook
242
251
        self.checker = None
243
252
        self.checker_initiator_tag = None
244
253
        self.stop_initiator_tag = None
245
254
        self.checker_callback_tag = None
246
 
        self.check_command = config["checker"]
 
255
        self.check_command = checker
247
256
    def start(self):
248
257
        """Start this client's checker and timeout hooks"""
249
258
        # Schedule a new checker to be started an 'interval' from now,
262
271
        The possibility that a client might be restarted is left open,
263
272
        but not currently used."""
264
273
        # If this client doesn't have a secret, it is already stopped.
265
 
        if hasattr(self, "secret") and self.secret:
266
 
            logger.info(u"Stopping client %s", self.name)
 
274
        if self.secret:
 
275
            logger.debug(u"Stopping client %s", self.name)
267
276
            self.secret = None
268
277
        else:
269
278
            return False
288
297
        self.checker = None
289
298
        if os.WIFEXITED(condition) \
290
299
               and (os.WEXITSTATUS(condition) == 0):
291
 
            logger.info(u"Checker for %(name)s succeeded",
292
 
                        vars(self))
 
300
            logger.debug(u"Checker for %(name)s succeeded",
 
301
                         vars(self))
293
302
            self.last_checked_ok = now
294
303
            gobject.source_remove(self.stop_initiator_tag)
295
304
            self.stop_initiator_tag = gobject.timeout_add\
299
308
            logger.warning(u"Checker for %(name)s crashed?",
300
309
                           vars(self))
301
310
        else:
302
 
            logger.info(u"Checker for %(name)s failed",
303
 
                        vars(self))
 
311
            logger.debug(u"Checker for %(name)s failed",
 
312
                         vars(self))
304
313
    def start_checker(self):
305
314
        """Start a new checker subprocess if one is not running.
306
315
        If a checker already exists, leave it running and do
316
325
        if self.checker is None:
317
326
            try:
318
327
                # In case check_command has exactly one % operator
319
 
                command = self.check_command % self.host
 
328
                command = self.check_command % self.fqdn
320
329
            except TypeError:
321
330
                # Escape attributes for the shell
322
331
                escaped_attrs = dict((key, re.escape(str(val)))
329
338
                                 u' %s', self.check_command, error)
330
339
                    return True # Try again later
331
340
            try:
332
 
                logger.info(u"Starting checker %r for %s",
333
 
                            command, self.name)
 
341
                logger.debug(u"Starting checker %r for %s",
 
342
                             command, self.name)
334
343
                self.checker = subprocess.Popen(command,
335
344
                                                close_fds=True,
336
345
                                                shell=True, cwd="/")
349
358
            self.checker_callback_tag = None
350
359
        if getattr(self, "checker", None) is None:
351
360
            return
352
 
        logger.debug(u"Stopping checker for %(name)s", vars(self))
 
361
        logger.debug("Stopping checker for %(name)s", vars(self))
353
362
        try:
354
363
            os.kill(self.checker.pid, signal.SIGTERM)
355
364
            #os.sleep(0.5)
387
396
 
388
397
def fingerprint(openpgp):
389
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\
 
402
        (ctypes.byref(crt))
390
403
    # New GnuTLS "datum" with the OpenPGP public key
391
404
    datum = gnutls.library.types.gnutls_datum_t\
392
405
        (ctypes.cast(ctypes.c_char_p(openpgp),
393
406
                     ctypes.POINTER(ctypes.c_ubyte)),
394
407
         ctypes.c_uint(len(openpgp)))
395
 
    # New empty GnuTLS certificate
396
 
    crt = gnutls.library.types.gnutls_openpgp_crt_t()
397
 
    gnutls.library.functions.gnutls_openpgp_crt_init\
398
 
        (ctypes.byref(crt))
399
408
    # Import the OpenPGP public key into the certificate
400
 
    gnutls.library.functions.gnutls_openpgp_crt_import\
401
 
                    (crt, ctypes.byref(datum),
402
 
                     gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
 
409
    ret = gnutls.library.functions.gnutls_openpgp_crt_import\
 
410
        (crt,
 
411
         ctypes.byref(datum),
 
412
         gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
403
413
    # New buffer for the fingerprint
404
414
    buffer = ctypes.create_string_buffer(20)
405
415
    buffer_length = ctypes.c_size_t()
421
431
    Note: This will run in its own forked process."""
422
432
    
423
433
    def handle(self):
424
 
        logger.info(u"TCP connection from: %s",
 
434
        logger.debug(u"TCP connection from: %s",
425
435
                     unicode(self.client_address))
426
436
        session = gnutls.connection.ClientSession\
427
437
                  (self.request, gnutls.connection.X509Credentials())
428
 
        
429
 
        line = self.request.makefile().readline()
430
 
        logger.debug(u"Protocol version: %r", line)
431
 
        try:
432
 
            if int(line.strip().split()[0]) > 1:
433
 
                raise RuntimeError
434
 
        except (ValueError, IndexError, RuntimeError), error:
435
 
            logger.error(u"Unknown protocol version: %s", error)
436
 
            return
437
 
        
438
438
        # Note: gnutls.connection.X509Credentials is really a generic
439
439
        # GnuTLS certificate credentials object so long as no X.509
440
440
        # keys are added to it.  Therefore, we can use it here despite
453
453
        try:
454
454
            session.handshake()
455
455
        except gnutls.errors.GNUTLSError, error:
456
 
            logger.warning(u"Handshake failed: %s", error)
 
456
            logger.debug(u"Handshake failed: %s", error)
457
457
            # Do not run session.bye() here: the session is not
458
458
            # established.  Just abandon the request.
459
459
            return
460
460
        try:
461
461
            fpr = fingerprint(peer_certificate(session))
462
462
        except (TypeError, gnutls.errors.GNUTLSError), error:
463
 
            logger.warning(u"Bad certificate: %s", error)
 
463
            logger.debug(u"Bad certificate: %s", error)
464
464
            session.bye()
465
465
            return
466
466
        logger.debug(u"Fingerprint: %s", fpr)
470
470
                client = c
471
471
                break
472
472
        if not client:
473
 
            logger.warning(u"Client not found for fingerprint: %s",
474
 
                           fpr)
 
473
            logger.debug(u"Client not found for fingerprint: %s", fpr)
475
474
            session.bye()
476
475
            return
477
476
        # Have to check if client.still_valid(), since it is possible
478
477
        # that the client timed out while establishing the GnuTLS
479
478
        # session.
480
479
        if not client.still_valid():
481
 
            logger.warning(u"Client %(name)s is invalid",
482
 
                           vars(client))
 
480
            logger.debug(u"Client %(name)s is invalid", vars(client))
483
481
            session.bye()
484
482
            return
485
483
        sent_size = 0
520
518
                                       self.settings["interface"])
521
519
            except socket.error, error:
522
520
                if error[0] == errno.EPERM:
523
 
                    logger.error(u"No permission to"
524
 
                                 u" bind to interface %s",
525
 
                                 self.settings["interface"])
 
521
                    logger.warning(u"No permission to"
 
522
                                   u" bind to interface %s",
 
523
                                   self.settings["interface"])
526
524
                else:
527
525
                    raise error
528
526
        # Only bind(2) the socket if we really need to.
531
529
                in6addr_any = "::"
532
530
                self.server_address = (in6addr_any,
533
531
                                       self.server_address[1])
534
 
            elif not self.server_address[1]:
 
532
            elif self.server_address[1] is None:
535
533
                self.server_address = (self.server_address[0],
536
534
                                       0)
537
 
#                 if self.settings["interface"]:
538
 
#                     self.server_address = (self.server_address[0],
539
 
#                                            0, # port
540
 
#                                            0, # flowinfo
541
 
#                                            if_nametoindex
542
 
#                                            (self.settings
543
 
#                                             ["interface"]))
544
535
            return super(type(self), self).server_bind()
545
536
 
546
537
 
581
572
def server_state_changed(state):
582
573
    """Derived from the Avahi example code"""
583
574
    if state == avahi.SERVER_COLLISION:
584
 
        logger.error(u"Server name collision")
 
575
        logger.warning(u"Server name collision")
585
576
        service.remove()
586
577
    elif state == avahi.SERVER_RUNNING:
587
578
        service.add()
601
592
                        unicode(error))
602
593
        raise AvahiGroupError("State changed: %s", str(error))
603
594
 
604
 
def if_nametoindex(interface):
 
595
def if_nametoindex(interface, _func=[None]):
605
596
    """Call the C function if_nametoindex(), or equivalent"""
606
 
    global if_nametoindex
 
597
    if _func[0] is not None:
 
598
        return _func[0](interface)
607
599
    try:
608
600
        if "ctypes.util" not in sys.modules:
609
601
            import ctypes.util
610
 
        if_nametoindex = ctypes.cdll.LoadLibrary\
611
 
            (ctypes.util.find_library("c")).if_nametoindex
 
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
612
611
    except (OSError, AttributeError):
613
612
        if "struct" not in sys.modules:
614
613
            import struct
615
614
        if "fcntl" not in sys.modules:
616
615
            import fcntl
617
 
        def if_nametoindex(interface):
 
616
        def the_hard_way(interface):
618
617
            "Get an interface index the hard way, i.e. using fcntl()"
619
618
            SIOCGIFINDEX = 0x8933  # From /usr/include/linux/sockios.h
620
619
            s = socket.socket()
623
622
            s.close()
624
623
            interface_index = struct.unpack("I", ifreq[16:20])[0]
625
624
            return interface_index
626
 
    return if_nametoindex(interface)
627
 
 
628
 
 
629
 
def daemon(nochdir = False, noclose = False):
 
625
        _func[0] = the_hard_way
 
626
        return _func[0](interface)
 
627
 
 
628
 
 
629
def daemon(nochdir, noclose):
630
630
    """See daemon(3).  Standard BSD Unix function.
631
631
    This should really exist as os.daemon, but it doesn't (yet)."""
632
632
    if os.fork():
634
634
    os.setsid()
635
635
    if not nochdir:
636
636
        os.chdir("/")
637
 
    if os.fork():
638
 
        sys.exit()
639
637
    if not noclose:
640
638
        # Close all standard open file descriptors
641
639
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
662
660
                      help="Port number to receive requests on")
663
661
    parser.add_option("--check", action="store_true", default=False,
664
662
                      help="Run self-test")
665
 
    parser.add_option("--debug", action="store_true",
 
663
    parser.add_option("--debug", action="store_true", default=False,
666
664
                      help="Debug mode; run in foreground and log to"
667
665
                      " terminal")
668
666
    parser.add_option("--priority", type="string", help="GnuTLS"
693
691
    # Parse config file for server-global settings
694
692
    server_config = ConfigParser.SafeConfigParser(server_defaults)
695
693
    del server_defaults
696
 
    server_config.read(os.path.join(options.configdir, "mandos.conf"))
 
694
    server_config.read(os.path.join(options.configdir, "server.conf"))
697
695
    server_section = "server"
698
696
    # Convert the SafeConfigParser object to a dict
699
697
    server_settings = dict(server_config.items(server_section))
712
710
    del options
713
711
    # Now we have our good server settings in "server_settings"
714
712
    
715
 
    debug = server_settings["debug"]
716
 
    
717
 
    if not debug:
718
 
        syslogger.setLevel(logging.WARNING)
719
 
    
720
 
    if server_settings["servicename"] != "Mandos":
721
 
        syslogger.setFormatter(logging.Formatter\
722
 
                               ('Mandos (%s): %%(levelname)s:'
723
 
                                ' %%(message)s'
724
 
                                % server_settings["servicename"]))
725
 
    
726
713
    # Parse config file with clients
727
714
    client_defaults = { "timeout": "1h",
728
715
                        "interval": "5m",
729
 
                        "checker": "fping -q -- %%(host)s",
 
716
                        "checker": "fping -q -- %%(fqdn)s",
730
717
                        }
731
718
    client_config = ConfigParser.SafeConfigParser(client_defaults)
732
719
    client_config.read(os.path.join(server_settings["configdir"],
750
737
            avahi.DBUS_INTERFACE_SERVER )
751
738
    # End of Avahi example code
752
739
    
 
740
    debug = server_settings["debug"]
 
741
    
753
742
    if debug:
754
743
        console = logging.StreamHandler()
755
744
        # console.setLevel(logging.DEBUG)
762
751
    def remove_from_clients(client):
763
752
        clients.remove(client)
764
753
        if not clients:
765
 
            logger.critical(u"No clients left, exiting")
 
754
            logger.debug(u"No clients left, exiting")
766
755
            sys.exit()
767
756
    
768
 
    clients.update(Set(Client(name = section,
 
757
    clients.update(Set(Client(name=section,
769
758
                              stop_hook = remove_from_clients,
770
 
                              config
771
 
                              = dict(client_config.items(section)))
 
759
                              **(dict(client_config\
 
760
                                      .items(section))))
772
761
                       for section in client_config.sections()))
773
 
    if not clients:
774
 
        logger.critical(u"No clients defined")
775
 
        sys.exit(1)
776
762
    
777
763
    if not debug:
778
 
        daemon()
779
 
    
780
 
    pidfilename = "/var/run/mandos/mandos.pid"
781
 
    pid = os.getpid()
782
 
    try:
783
 
        pidfile = open(pidfilename, "w")
784
 
        pidfile.write(str(pid) + "\n")
785
 
        pidfile.close()
786
 
        del pidfile
787
 
    except IOError, err:
788
 
        logger.error(u"Could not write %s file with PID %d",
789
 
                     pidfilename, os.getpid())
 
764
        daemon(False, False)
790
765
    
791
766
    def cleanup():
792
767
        "Cleanup function; run on exit"
819
794
                                clients=clients)
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 address %r, port %d, flowinfo %d,"
 
798
                 u" scope_id %d" % tcp_server.socket.getsockname())
824
799
    
825
800
    #service.interface = tcp_server.socket.getsockname()[3]
826
801
    
839
814
                             tcp_server.handle_request\
840
815
                             (*args[2:], **kwargs) or True)
841
816
        
842
 
        logger.debug(u"Starting main loop")
 
817
        logger.debug("Starting main loop")
843
818
        main_loop_started = True
844
819
        main_loop.run()
845
820
    except AvahiError, error: