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  • Committer: Teddy Hogeborn
  • Date: 2008-08-04 21:25:55 UTC
  • Revision ID: teddy@fukt.bsnet.se-20080804212555-rm7xxjze65f8avy3
* server.py: Cosmetic changes.

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server.py
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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
24
24
#     GNU General Public License for more details.
25
25
# 
26
26
# You should have received a copy of the GNU General Public License
27
 
# along with this program.  If not, see
28
 
# <http://www.gnu.org/licenses/>.
 
27
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
29
28
# 
30
29
# Contact the authors at <mandos@fukt.bsnet.se>.
31
30
# 
55
54
import stat
56
55
import logging
57
56
import logging.handlers
58
 
import pwd
59
57
 
60
58
import dbus
61
59
import gobject
63
61
from dbus.mainloop.glib import DBusGMainLoop
64
62
import ctypes
65
63
 
66
 
version = "1.0"
 
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
 
67
75
 
68
76
logger = logging.Logger('mandos')
69
77
syslogger = logging.handlers.SysLogHandler\
70
 
            (facility = logging.handlers.SysLogHandler.LOG_DAEMON,
71
 
             address = "/dev/log")
 
78
            (facility = logging.handlers.SysLogHandler.LOG_DAEMON)
72
79
syslogger.setFormatter(logging.Formatter\
73
 
                        ('Mandos: %(levelname)s: %(message)s'))
 
80
                        ('%(levelname)s: %(message)s'))
74
81
logger.addHandler(syslogger)
 
82
del syslogger
75
83
 
76
 
console = logging.StreamHandler()
77
 
console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
78
 
                                       ' %(message)s'))
79
 
logger.addHandler(console)
80
84
 
81
85
class AvahiError(Exception):
82
86
    def __init__(self, value):
109
113
    """
110
114
    def __init__(self, interface = avahi.IF_UNSPEC, name = None,
111
115
                 type = None, port = None, TXT = None, domain = "",
112
 
                 host = "", max_renames = 32768):
 
116
                 host = "", max_renames = 12):
113
117
        self.interface = interface
114
118
        self.name = name
115
119
        self.type = type
121
125
        self.domain = domain
122
126
        self.host = host
123
127
        self.rename_count = 0
124
 
        self.max_renames = max_renames
125
128
    def rename(self):
126
129
        """Derived from the Avahi example code"""
127
130
        if self.rename_count >= self.max_renames:
128
 
            logger.critical(u"No suitable Zeroconf service name found"
129
 
                            u" after %i retries, exiting.",
130
 
                            rename_count)
 
131
            logger.critical(u"No suitable service name found after %i"
 
132
                            u" retries, exiting.", rename_count)
131
133
            raise AvahiServiceError("Too many renames")
132
 
        self.name = server.GetAlternativeServiceName(self.name)
133
 
        logger.info(u"Changing Zeroconf service name to %r ...",
134
 
                    str(self.name))
135
 
        syslogger.setFormatter(logging.Formatter\
136
 
                               ('Mandos (%s): %%(levelname)s:'
137
 
                               ' %%(message)s' % self.name))
 
134
        name = server.GetAlternativeServiceName(name)
 
135
        logger.error(u"Changing name to %r ...", name)
138
136
        self.remove()
139
137
        self.add()
140
138
        self.rename_count += 1
152
150
                     avahi.DBUS_INTERFACE_ENTRY_GROUP)
153
151
            group.connect_to_signal('StateChanged',
154
152
                                    entry_group_state_changed)
155
 
        logger.debug(u"Adding Zeroconf service '%s' of type '%s' ...",
 
153
        logger.debug(u"Adding service '%s' of type '%s' ...",
156
154
                     service.name, service.type)
157
155
        group.AddService(
158
156
                self.interface,         # interface
176
174
    fingerprint: string (40 or 32 hexadecimal digits); used to
177
175
                 uniquely identify the client
178
176
    secret:    bytestring; sent verbatim (over TLS) to client
179
 
    host:      string; available for use by the checker command
 
177
    fqdn:      string (FQDN); available for use by the checker command
180
178
    created:   datetime.datetime(); object creation, not client host
181
179
    last_checked_ok: datetime.datetime() or None if not yet checked OK
182
180
    timeout:   datetime.timedelta(); How long from last_checked_ok
243
241
        else:
244
242
            raise TypeError(u"No secret or secfile for client %s"
245
243
                            % self.name)
246
 
        self.host = config.get("host", "")
 
244
        self.fqdn = config.get("fqdn", "")
247
245
        self.created = datetime.datetime.now()
248
246
        self.last_checked_ok = None
249
247
        self.timeout = string_to_delta(config["timeout"])
272
270
        The possibility that a client might be restarted is left open,
273
271
        but not currently used."""
274
272
        # If this client doesn't have a secret, it is already stopped.
275
 
        if hasattr(self, "secret") and self.secret:
 
273
        if self.secret:
276
274
            logger.info(u"Stopping client %s", self.name)
277
275
            self.secret = None
278
276
        else:
326
324
        if self.checker is None:
327
325
            try:
328
326
                # In case check_command has exactly one % operator
329
 
                command = self.check_command % self.host
 
327
                command = self.check_command % self.fqdn
330
328
            except TypeError:
331
329
                # Escape attributes for the shell
332
330
                escaped_attrs = dict((key, re.escape(str(val)))
341
339
            try:
342
340
                logger.info(u"Starting checker %r for %s",
343
341
                            command, self.name)
344
 
                # We don't need to redirect stdout and stderr, since
345
 
                # in normal mode, that is already done by daemon(),
346
 
                # and in debug mode we don't want to.  (Stdin is
347
 
                # always replaced by /dev/null.)
348
342
                self.checker = subprocess.Popen(command,
349
343
                                                close_fds=True,
350
344
                                                shell=True, cwd="/")
351
345
                self.checker_callback_tag = gobject.child_watch_add\
352
346
                                            (self.checker.pid,
353
347
                                             self.checker_callback)
354
 
            except OSError, error:
 
348
            except subprocess.OSError, error:
355
349
                logger.error(u"Failed to start subprocess: %s",
356
350
                             error)
357
351
        # Re-run this periodically if run by gobject.timeout_add
363
357
            self.checker_callback_tag = None
364
358
        if getattr(self, "checker", None) is None:
365
359
            return
366
 
        logger.debug(u"Stopping checker for %(name)s", vars(self))
 
360
        logger.debug("Stopping checker for %(name)s", vars(self))
367
361
        try:
368
362
            os.kill(self.checker.pid, signal.SIGTERM)
369
363
            #os.sleep(0.5)
414
408
    gnutls.library.functions.gnutls_openpgp_crt_import\
415
409
                    (crt, ctypes.byref(datum),
416
410
                     gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
417
 
    # Verify the self signature in the key
418
 
    crtverify = ctypes.c_uint();
419
 
    gnutls.library.functions.gnutls_openpgp_crt_verify_self\
420
 
        (crt, 0, ctypes.byref(crtverify))
421
 
    if crtverify.value != 0:
422
 
        gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
423
 
        raise gnutls.errors.CertificateSecurityError("Verify failed")
424
411
    # New buffer for the fingerprint
425
412
    buffer = ctypes.create_string_buffer(20)
426
413
    buffer_length = ctypes.c_size_t()
518
505
    Attributes:
519
506
        settings:       Server settings
520
507
        clients:        Set() of Client objects
521
 
        enabled:        Boolean; whether this server is activated yet
522
508
    """
523
509
    address_family = socket.AF_INET6
524
510
    def __init__(self, *args, **kwargs):
528
514
        if "clients" in kwargs:
529
515
            self.clients = kwargs["clients"]
530
516
            del kwargs["clients"]
531
 
        self.enabled = False
532
517
        return super(type(self), self).__init__(*args, **kwargs)
533
518
    def server_bind(self):
534
519
        """This overrides the normal server_bind() function
554
539
                in6addr_any = "::"
555
540
                self.server_address = (in6addr_any,
556
541
                                       self.server_address[1])
557
 
            elif not self.server_address[1]:
 
542
            elif self.server_address[1] is None:
558
543
                self.server_address = (self.server_address[0],
559
544
                                       0)
560
 
#                 if self.settings["interface"]:
561
 
#                     self.server_address = (self.server_address[0],
562
 
#                                            0, # port
563
 
#                                            0, # flowinfo
564
 
#                                            if_nametoindex
565
 
#                                            (self.settings
566
 
#                                             ["interface"]))
567
545
            return super(type(self), self).server_bind()
568
 
    def server_activate(self):
569
 
        if self.enabled:
570
 
            return super(type(self), self).server_activate()
571
 
    def enable(self):
572
 
        self.enabled = True
573
546
 
574
547
 
575
548
def string_to_delta(interval):
585
558
    datetime.timedelta(1)
586
559
    >>> string_to_delta(u'1w')
587
560
    datetime.timedelta(7)
588
 
    >>> string_to_delta('5m 30s')
589
 
    datetime.timedelta(0, 330)
590
561
    """
591
 
    timevalue = datetime.timedelta(0)
592
 
    for s in interval.split():
593
 
        try:
594
 
            suffix=unicode(s[-1])
595
 
            value=int(s[:-1])
596
 
            if suffix == u"d":
597
 
                delta = datetime.timedelta(value)
598
 
            elif suffix == u"s":
599
 
                delta = datetime.timedelta(0, value)
600
 
            elif suffix == u"m":
601
 
                delta = datetime.timedelta(0, 0, 0, 0, value)
602
 
            elif suffix == u"h":
603
 
                delta = datetime.timedelta(0, 0, 0, 0, 0, value)
604
 
            elif suffix == u"w":
605
 
                delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
606
 
            else:
607
 
                raise ValueError
608
 
        except (ValueError, IndexError):
 
562
    try:
 
563
        suffix=unicode(interval[-1])
 
564
        value=int(interval[:-1])
 
565
        if suffix == u"d":
 
566
            delta = datetime.timedelta(value)
 
567
        elif suffix == u"s":
 
568
            delta = datetime.timedelta(0, value)
 
569
        elif suffix == u"m":
 
570
            delta = datetime.timedelta(0, 0, 0, 0, value)
 
571
        elif suffix == u"h":
 
572
            delta = datetime.timedelta(0, 0, 0, 0, 0, value)
 
573
        elif suffix == u"w":
 
574
            delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
 
575
        else:
609
576
            raise ValueError
610
 
        timevalue += delta
611
 
    return timevalue
 
577
    except (ValueError, IndexError):
 
578
        raise ValueError
 
579
    return delta
612
580
 
613
581
 
614
582
def server_state_changed(state):
615
583
    """Derived from the Avahi example code"""
616
584
    if state == avahi.SERVER_COLLISION:
617
 
        logger.error(u"Zeroconf server name collision")
 
585
        logger.error(u"Server name collision")
618
586
        service.remove()
619
587
    elif state == avahi.SERVER_RUNNING:
620
588
        service.add()
622
590
 
623
591
def entry_group_state_changed(state, error):
624
592
    """Derived from the Avahi example code"""
625
 
    logger.debug(u"Avahi state change: %i", state)
 
593
    logger.debug(u"state change: %i", state)
626
594
    
627
595
    if state == avahi.ENTRY_GROUP_ESTABLISHED:
628
 
        logger.debug(u"Zeroconf service established.")
 
596
        logger.debug(u"Service established.")
629
597
    elif state == avahi.ENTRY_GROUP_COLLISION:
630
 
        logger.warning(u"Zeroconf service name collision.")
 
598
        logger.warning(u"Service name collision.")
631
599
        service.rename()
632
600
    elif state == avahi.ENTRY_GROUP_FAILURE:
633
 
        logger.critical(u"Avahi: Error in group state changed %s",
 
601
        logger.critical(u"Error in group state changed %s",
634
602
                        unicode(error))
635
603
        raise AvahiGroupError("State changed: %s", str(error))
636
604
 
659
627
    return if_nametoindex(interface)
660
628
 
661
629
 
662
 
def daemon(nochdir = False, noclose = False):
 
630
def daemon(nochdir, noclose):
663
631
    """See daemon(3).  Standard BSD Unix function.
664
632
    This should really exist as os.daemon, but it doesn't (yet)."""
665
633
    if os.fork():
667
635
    os.setsid()
668
636
    if not nochdir:
669
637
        os.chdir("/")
670
 
    if os.fork():
671
 
        sys.exit()
672
638
    if not noclose:
673
639
        # Close all standard open file descriptors
674
640
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
686
652
    global main_loop_started
687
653
    main_loop_started = False
688
654
    
689
 
    parser = OptionParser(version = "%%prog %s" % version)
 
655
    parser = OptionParser()
690
656
    parser.add_option("-i", "--interface", type="string",
691
657
                      metavar="IF", help="Bind to interface IF")
692
658
    parser.add_option("-a", "--address", type="string",
695
661
                      help="Port number to receive requests on")
696
662
    parser.add_option("--check", action="store_true", default=False,
697
663
                      help="Run self-test")
698
 
    parser.add_option("--debug", action="store_true",
 
664
    parser.add_option("--debug", action="store_true", default=False,
699
665
                      help="Debug mode; run in foreground and log to"
700
666
                      " terminal")
701
667
    parser.add_option("--priority", type="string", help="GnuTLS"
726
692
    # Parse config file for server-global settings
727
693
    server_config = ConfigParser.SafeConfigParser(server_defaults)
728
694
    del server_defaults
729
 
    server_config.read(os.path.join(options.configdir, "mandos.conf"))
 
695
    server_config.read(os.path.join(options.configdir, "server.conf"))
 
696
    server_section = "server"
730
697
    # Convert the SafeConfigParser object to a dict
731
 
    server_settings = server_config.defaults()
 
698
    server_settings = dict(server_config.items(server_section))
732
699
    # Use getboolean on the boolean config option
733
700
    server_settings["debug"] = server_config.getboolean\
734
 
                               ("DEFAULT", "debug")
 
701
                               (server_section, "debug")
735
702
    del server_config
736
703
    
737
704
    # Override the settings from the config file with command line
744
711
    del options
745
712
    # Now we have our good server settings in "server_settings"
746
713
    
747
 
    debug = server_settings["debug"]
748
 
    
749
 
    if not debug:
750
 
        syslogger.setLevel(logging.WARNING)
751
 
        console.setLevel(logging.WARNING)
752
 
    
753
 
    if server_settings["servicename"] != "Mandos":
754
 
        syslogger.setFormatter(logging.Formatter\
755
 
                               ('Mandos (%s): %%(levelname)s:'
756
 
                                ' %%(message)s'
757
 
                                % server_settings["servicename"]))
758
 
    
759
714
    # Parse config file with clients
760
715
    client_defaults = { "timeout": "1h",
761
716
                        "interval": "5m",
762
 
                        "checker": "fping -q -- %(host)s",
763
 
                        "host": "",
 
717
                        "checker": "fping -q -- %%(fqdn)s",
764
718
                        }
765
719
    client_config = ConfigParser.SafeConfigParser(client_defaults)
766
720
    client_config.read(os.path.join(server_settings["configdir"],
767
721
                                    "clients.conf"))
768
722
    
769
 
    clients = Set()
770
 
    tcp_server = IPv6_TCPServer((server_settings["address"],
771
 
                                 server_settings["port"]),
772
 
                                tcp_handler,
773
 
                                settings=server_settings,
774
 
                                clients=clients)
775
 
    pidfilename = "/var/run/mandos.pid"
776
 
    try:
777
 
        pidfile = open(pidfilename, "w")
778
 
    except IOError, error:
779
 
        logger.error("Could not open file %r", pidfilename)
780
 
    
781
 
    uid = 65534
782
 
    gid = 65534
783
 
    try:
784
 
        uid = pwd.getpwnam("mandos").pw_uid
785
 
    except KeyError:
786
 
        try:
787
 
            uid = pwd.getpwnam("nobody").pw_uid
788
 
        except KeyError:
789
 
            pass
790
 
    try:
791
 
        gid = pwd.getpwnam("mandos").pw_gid
792
 
    except KeyError:
793
 
        try:
794
 
            gid = pwd.getpwnam("nogroup").pw_gid
795
 
        except KeyError:
796
 
            pass
797
 
    try:
798
 
        os.setuid(uid)
799
 
        os.setgid(gid)
800
 
    except OSError, error:
801
 
        if error[0] != errno.EPERM:
802
 
            raise error
803
 
    
804
723
    global service
805
724
    service = AvahiService(name = server_settings["servicename"],
806
725
                           type = "_mandos._tcp", );
807
726
    if server_settings["interface"]:
808
 
        service.interface = if_nametoindex\
809
 
                            (server_settings["interface"])
 
727
        service.interface = if_nametoindex(server_settings["interface"])
810
728
    
811
729
    global main_loop
812
730
    global bus
815
733
    DBusGMainLoop(set_as_default=True )
816
734
    main_loop = gobject.MainLoop()
817
735
    bus = dbus.SystemBus()
818
 
    server = dbus.Interface(bus.get_object(avahi.DBUS_NAME,
819
 
                                           avahi.DBUS_PATH_SERVER),
820
 
                            avahi.DBUS_INTERFACE_SERVER)
 
736
    server = dbus.Interface(
 
737
            bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
 
738
            avahi.DBUS_INTERFACE_SERVER )
821
739
    # End of Avahi example code
822
740
    
 
741
    debug = server_settings["debug"]
 
742
    
 
743
    if debug:
 
744
        console = logging.StreamHandler()
 
745
        # console.setLevel(logging.DEBUG)
 
746
        console.setFormatter(logging.Formatter\
 
747
                             ('%(levelname)s: %(message)s'))
 
748
        logger.addHandler(console)
 
749
        del console
 
750
    
 
751
    clients = Set()
823
752
    def remove_from_clients(client):
824
753
        clients.remove(client)
825
754
        if not clients:
831
760
                              config
832
761
                              = dict(client_config.items(section)))
833
762
                       for section in client_config.sections()))
834
 
    if not clients:
835
 
        logger.critical(u"No clients defined")
836
 
        sys.exit(1)
837
 
    
838
 
    if debug:
839
 
        # Redirect stdin so all checkers get /dev/null
840
 
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
841
 
        os.dup2(null, sys.stdin.fileno())
842
 
        if null > 2:
843
 
            os.close(null)
844
 
    else:
845
 
        # No console logging
846
 
        logger.removeHandler(console)
847
 
        # Close all input and output, do double fork, etc.
848
 
        daemon()
849
 
    
850
 
    try:
851
 
        pid = os.getpid()
852
 
        pidfile.write(str(pid) + "\n")
853
 
        pidfile.close()
854
 
        del pidfile
855
 
    except IOError, err:
856
 
        logger.error(u"Could not write to file %r with PID %d",
857
 
                     pidfilename, pid)
858
 
    except NameError:
859
 
        # "pidfile" was never created
860
 
        pass
861
 
    del pidfilename
 
763
    
 
764
    if not debug:
 
765
        daemon(False, False)
862
766
    
863
767
    def cleanup():
864
768
        "Cleanup function; run on exit"
884
788
    for client in clients:
885
789
        client.start()
886
790
    
887
 
    tcp_server.enable()
888
 
    tcp_server.server_activate()
889
 
    
 
791
    tcp_server = IPv6_TCPServer((server_settings["address"],
 
792
                                 server_settings["port"]),
 
793
                                tcp_handler,
 
794
                                settings=server_settings,
 
795
                                clients=clients)
890
796
    # Find out what port we got
891
797
    service.port = tcp_server.socket.getsockname()[1]
892
798
    logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
909
815
                             tcp_server.handle_request\
910
816
                             (*args[2:], **kwargs) or True)
911
817
        
912
 
        logger.debug(u"Starting main loop")
 
818
        logger.debug("Starting main loop")
913
819
        main_loop_started = True
914
820
        main_loop.run()
915
821
    except AvahiError, error: