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
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".
13
13
# Everything else is
14
14
# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
24
24
# GNU General Public License for more details.
26
26
# You should have received a copy of the GNU General Public License
27
# along with this program. If not, see <http://www.gnu.org/licenses/>.
27
# along with this program. If not, see
28
# <http://www.gnu.org/licenses/>.
29
30
# Contact the authors at <mandos@fukt.bsnet.se>.
61
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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.
76
67
logger = logging.Logger('mandos')
77
68
syslogger = logging.handlers.SysLogHandler\
78
(facility = logging.handlers.SysLogHandler.LOG_DAEMON)
69
(facility = logging.handlers.SysLogHandler.LOG_DAEMON,
79
71
syslogger.setFormatter(logging.Formatter\
80
('%(levelname)s: %(message)s'))
72
('Mandos: %(levelname)s: %(message)s'))
81
73
logger.addHandler(syslogger)
75
console = logging.StreamHandler()
76
console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
78
logger.addHandler(console)
85
80
class AvahiError(Exception):
86
81
def __init__(self, value):
98
93
class AvahiService(object):
94
"""An Avahi (Zeroconf) service.
100
96
interface: integer; avahi.IF_UNSPEC or an interface index.
101
97
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
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
98
name: string; Example: 'Mandos'
99
type: string; Example: '_mandos._tcp'.
100
See <http://www.dns-sd.org/ServiceTypes.html>
101
port: integer; what port to announce
102
TXT: list of strings; TXT record for the service
103
domain: string; Domain to publish on, default to .local if empty.
104
host: string; Host to publish records for, default is localhost
105
max_renames: integer; maximum number of renames
106
rename_count: integer; counter so we only rename after collisions
107
a sensible number of times
114
109
def __init__(self, interface = avahi.IF_UNSPEC, name = None,
115
110
type = None, port = None, TXT = None, domain = "",
116
host = "", max_renames = 12):
117
"""An Avahi (Zeroconf) service. """
111
host = "", max_renames = 32768):
118
112
self.interface = interface
126
120
self.domain = domain
128
122
self.rename_count = 0
123
self.max_renames = max_renames
129
124
def rename(self):
130
125
"""Derived from the Avahi example code"""
131
126
if self.rename_count >= self.max_renames:
132
logger.critical(u"No suitable service name found after %i"
133
u" retries, exiting.", rename_count)
127
logger.critical(u"No suitable Zeroconf service name found"
128
u" after %i retries, exiting.",
134
130
raise AvahiServiceError("Too many renames")
135
name = server.GetAlternativeServiceName(name)
136
logger.notice(u"Changing name to %r ...", name)
131
self.name = server.GetAlternativeServiceName(self.name)
132
logger.info(u"Changing Zeroconf service name to %r ...",
134
syslogger.setFormatter(logging.Formatter\
135
('Mandos (%s): %%(levelname)s:'
136
' %%(message)s' % self.name))
139
139
self.rename_count += 1
151
151
avahi.DBUS_INTERFACE_ENTRY_GROUP)
152
152
group.connect_to_signal('StateChanged',
153
153
entry_group_state_changed)
154
logger.debug(u"Adding service '%s' of type '%s' ...",
154
logger.debug(u"Adding Zeroconf service '%s' of type '%s' ...",
155
155
service.name, service.type)
156
156
group.AddService(
157
157
self.interface, # interface
175
175
fingerprint: string (40 or 32 hexadecimal digits); used to
176
176
uniquely identify the client
177
177
secret: bytestring; sent verbatim (over TLS) to client
178
fqdn: string (FQDN); available for use by the checker command
178
host: string; available for use by the checker command
179
179
created: datetime.datetime(); object creation, not client host
180
180
last_checked_ok: datetime.datetime() or None if not yet checked OK
181
181
timeout: datetime.timedelta(); How long from last_checked_ok
221
221
interval = property(lambda self: self._interval,
223
223
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.."""
224
def __init__(self, name = None, stop_hook=None, config={}):
225
"""Note: the 'checker' key in 'config' sets the
226
'checker_command' attribute and *not* the 'checker'
230
229
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"")
230
# Uppercase and remove spaces from fingerprint for later
231
# comparison purposes with return value from the fingerprint()
233
self.fingerprint = config["fingerprint"].upper()\
235
235
logger.debug(u" Fingerprint: %s", self.fingerprint)
237
self.secret = secret.decode(u"base64")
236
if "secret" in config:
237
self.secret = config["secret"].decode(u"base64")
238
elif "secfile" in config:
239
sf = open(config["secfile"])
240
240
self.secret = sf.read()
243
243
raise TypeError(u"No secret or secfile for client %s"
245
self.host = config.get("host", "")
246
246
self.created = datetime.datetime.now()
247
247
self.last_checked_ok = None
248
self.timeout = string_to_delta(timeout)
249
self.interval = string_to_delta(interval)
248
self.timeout = string_to_delta(config["timeout"])
249
self.interval = string_to_delta(config["interval"])
250
250
self.stop_hook = stop_hook
251
251
self.checker = None
252
252
self.checker_initiator_tag = None
253
253
self.stop_initiator_tag = None
254
254
self.checker_callback_tag = None
255
self.check_command = checker
255
self.check_command = config["checker"]
257
257
"""Start this client's checker and timeout hooks"""
258
258
# Schedule a new checker to be started an 'interval' from now,
271
271
The possibility that a client might be restarted is left open,
272
272
but not currently used."""
273
273
# If this client doesn't have a secret, it is already stopped.
275
logger.debug(u"Stopping client %s", self.name)
274
if hasattr(self, "secret") and self.secret:
275
logger.info(u"Stopping client %s", self.name)
276
276
self.secret = None
297
297
self.checker = None
298
298
if os.WIFEXITED(condition) \
299
299
and (os.WEXITSTATUS(condition) == 0):
300
logger.debug(u"Checker for %(name)s succeeded",
300
logger.info(u"Checker for %(name)s succeeded",
302
302
self.last_checked_ok = now
303
303
gobject.source_remove(self.stop_initiator_tag)
304
304
self.stop_initiator_tag = gobject.timeout_add\
308
308
logger.warning(u"Checker for %(name)s crashed?",
311
logger.debug(u"Checker for %(name)s failed",
311
logger.info(u"Checker for %(name)s failed",
313
313
def start_checker(self):
314
314
"""Start a new checker subprocess if one is not running.
315
315
If a checker already exists, leave it running and do
338
338
u' %s', self.check_command, error)
339
339
return True # Try again later
341
logger.debug(u"Starting checker %r for %s",
341
logger.info(u"Starting checker %r for %s",
343
# We don't need to redirect stdout and stderr, since
344
# in normal mode, that is already done by daemon(),
345
# and in debug mode we don't want to. (Stdin is
346
# always replaced by /dev/null.)
343
347
self.checker = subprocess.Popen(command,
345
349
shell=True, cwd="/")
346
350
self.checker_callback_tag = gobject.child_watch_add\
347
351
(self.checker.pid,
348
352
self.checker_callback)
349
except subprocess.OSError, error:
353
except OSError, error:
350
354
logger.error(u"Failed to start subprocess: %s",
352
356
# Re-run this periodically if run by gobject.timeout_add
358
362
self.checker_callback_tag = None
359
363
if getattr(self, "checker", None) is None:
361
logger.debug("Stopping checker for %(name)s", vars(self))
365
logger.debug(u"Stopping checker for %(name)s", vars(self))
363
367
os.kill(self.checker.pid, signal.SIGTERM)
397
401
def fingerprint(openpgp):
398
402
"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\
403
403
# New GnuTLS "datum" with the OpenPGP public key
404
404
datum = gnutls.library.types.gnutls_datum_t\
405
405
(ctypes.cast(ctypes.c_char_p(openpgp),
406
406
ctypes.POINTER(ctypes.c_ubyte)),
407
407
ctypes.c_uint(len(openpgp)))
408
# New empty GnuTLS certificate
409
crt = gnutls.library.types.gnutls_openpgp_crt_t()
410
gnutls.library.functions.gnutls_openpgp_crt_init\
408
412
# Import the OpenPGP public key into the certificate
409
ret = gnutls.library.functions.gnutls_openpgp_crt_import\
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
413
gnutls.library.functions.gnutls_openpgp_crt_import\
414
(crt, ctypes.byref(datum),
415
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
416
# Verify the self signature in the key
417
crtverify = ctypes.c_uint();
418
gnutls.library.functions.gnutls_openpgp_crt_verify_self\
419
(crt, 0, ctypes.byref(crtverify))
420
if crtverify.value != 0:
421
gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
422
raise gnutls.errors.CertificateSecurityError("Verify failed")
413
423
# New buffer for the fingerprint
414
424
buffer = ctypes.create_string_buffer(20)
415
425
buffer_length = ctypes.c_size_t()
431
441
Note: This will run in its own forked process."""
433
443
def handle(self):
434
logger.debug(u"TCP connection from: %s",
444
logger.info(u"TCP connection from: %s",
435
445
unicode(self.client_address))
436
446
session = gnutls.connection.ClientSession\
437
447
(self.request, gnutls.connection.X509Credentials())
449
line = self.request.makefile().readline()
450
logger.debug(u"Protocol version: %r", line)
452
if int(line.strip().split()[0]) > 1:
454
except (ValueError, IndexError, RuntimeError), error:
455
logger.error(u"Unknown protocol version: %s", error)
438
458
# Note: gnutls.connection.X509Credentials is really a generic
439
459
# GnuTLS certificate credentials object so long as no X.509
440
460
# keys are added to it. Therefore, we can use it here despite
454
474
session.handshake()
455
475
except gnutls.errors.GNUTLSError, error:
456
logger.debug(u"Handshake failed: %s", error)
476
logger.warning(u"Handshake failed: %s", error)
457
477
# Do not run session.bye() here: the session is not
458
478
# established. Just abandon the request.
461
481
fpr = fingerprint(peer_certificate(session))
462
482
except (TypeError, gnutls.errors.GNUTLSError), error:
463
logger.debug(u"Bad certificate: %s", error)
483
logger.warning(u"Bad certificate: %s", error)
466
486
logger.debug(u"Fingerprint: %s", fpr)
473
logger.debug(u"Client not found for fingerprint: %s", fpr)
493
logger.warning(u"Client not found for fingerprint: %s",
476
497
# Have to check if client.still_valid(), since it is possible
477
498
# that the client timed out while establishing the GnuTLS
479
500
if not client.still_valid():
480
logger.debug(u"Client %(name)s is invalid", vars(client))
501
logger.warning(u"Client %(name)s is invalid",
518
540
self.settings["interface"])
519
541
except socket.error, error:
520
542
if error[0] == errno.EPERM:
521
logger.warning(u"No permission to"
522
u" bind to interface %s",
523
self.settings["interface"])
543
logger.error(u"No permission to"
544
u" bind to interface %s",
545
self.settings["interface"])
526
548
# Only bind(2) the socket if we really need to.
529
551
in6addr_any = "::"
530
552
self.server_address = (in6addr_any,
531
553
self.server_address[1])
532
elif self.server_address[1] is None:
554
elif not self.server_address[1]:
533
555
self.server_address = (self.server_address[0],
557
# if self.settings["interface"]:
558
# self.server_address = (self.server_address[0],
535
564
return super(type(self), self).server_bind()
548
577
datetime.timedelta(1)
549
578
>>> string_to_delta(u'1w')
550
579
datetime.timedelta(7)
580
>>> string_to_delta('5m 30s')
581
datetime.timedelta(0, 330)
553
suffix=unicode(interval[-1])
554
value=int(interval[:-1])
556
delta = datetime.timedelta(value)
558
delta = datetime.timedelta(0, value)
560
delta = datetime.timedelta(0, 0, 0, 0, value)
562
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
564
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
583
timevalue = datetime.timedelta(0)
584
for s in interval.split():
586
suffix=unicode(s[-1])
589
delta = datetime.timedelta(value)
591
delta = datetime.timedelta(0, value)
593
delta = datetime.timedelta(0, 0, 0, 0, value)
595
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
597
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
600
except (ValueError, IndexError):
567
except (ValueError, IndexError):
572
606
def server_state_changed(state):
573
607
"""Derived from the Avahi example code"""
574
608
if state == avahi.SERVER_COLLISION:
575
logger.warning(u"Server name collision")
609
logger.error(u"Zeroconf server name collision")
577
611
elif state == avahi.SERVER_RUNNING:
581
615
def entry_group_state_changed(state, error):
582
616
"""Derived from the Avahi example code"""
583
logger.debug(u"state change: %i", state)
617
logger.debug(u"Avahi state change: %i", state)
585
619
if state == avahi.ENTRY_GROUP_ESTABLISHED:
586
logger.debug(u"Service established.")
620
logger.debug(u"Zeroconf service established.")
587
621
elif state == avahi.ENTRY_GROUP_COLLISION:
588
logger.warning(u"Service name collision.")
622
logger.warning(u"Zeroconf service name collision.")
590
624
elif state == avahi.ENTRY_GROUP_FAILURE:
591
logger.critical(u"Error in group state changed %s",
625
logger.critical(u"Avahi: Error in group state changed %s",
593
627
raise AvahiGroupError("State changed: %s", str(error))
595
def if_nametoindex(interface, _func=[None]):
629
def if_nametoindex(interface):
596
630
"""Call the C function if_nametoindex(), or equivalent"""
597
if _func[0] is not None:
598
return _func[0](interface)
631
global if_nametoindex
600
633
if "ctypes.util" not in sys.modules:
601
634
import ctypes.util
604
libc = ctypes.cdll.LoadLibrary\
605
(ctypes.util.find_library("c"))
606
_func[0] = libc.if_nametoindex
607
return _func[0](interface)
635
if_nametoindex = ctypes.cdll.LoadLibrary\
636
(ctypes.util.find_library("c")).if_nametoindex
611
637
except (OSError, AttributeError):
612
638
if "struct" not in sys.modules:
614
640
if "fcntl" not in sys.modules:
616
def the_hard_way(interface):
642
def if_nametoindex(interface):
617
643
"Get an interface index the hard way, i.e. using fcntl()"
618
644
SIOCGIFINDEX = 0x8933 # From /usr/include/linux/sockios.h
619
645
s = socket.socket()
623
649
interface_index = struct.unpack("I", ifreq[16:20])[0]
624
650
return interface_index
625
_func[0] = the_hard_way
626
return _func[0](interface)
629
def daemon(nochdir, noclose):
651
return if_nametoindex(interface)
654
def daemon(nochdir = False, noclose = False):
630
655
"""See daemon(3). Standard BSD Unix function.
631
656
This should really exist as os.daemon, but it doesn't (yet)."""
651
678
global main_loop_started
652
679
main_loop_started = False
654
parser = OptionParser()
681
parser = OptionParser(version = "%%prog %s" % version)
655
682
parser.add_option("-i", "--interface", type="string",
656
683
metavar="IF", help="Bind to interface IF")
657
684
parser.add_option("-a", "--address", type="string",
660
687
help="Port number to receive requests on")
661
688
parser.add_option("--check", action="store_true", default=False,
662
689
help="Run self-test")
663
parser.add_option("--debug", action="store_true", default=False,
690
parser.add_option("--debug", action="store_true",
664
691
help="Debug mode; run in foreground and log to"
666
693
parser.add_option("--priority", type="string", help="GnuTLS"
691
718
# Parse config file for server-global settings
692
719
server_config = ConfigParser.SafeConfigParser(server_defaults)
693
720
del server_defaults
694
server_config.read(os.path.join(options.configdir, "server.conf"))
695
server_section = "server"
721
server_config.read(os.path.join(options.configdir, "mandos.conf"))
696
722
# Convert the SafeConfigParser object to a dict
697
server_settings = dict(server_config.items(server_section))
723
server_settings = server_config.defaults()
698
724
# Use getboolean on the boolean config option
699
725
server_settings["debug"] = server_config.getboolean\
700
(server_section, "debug")
701
727
del server_config
703
729
# Override the settings from the config file with command line
711
737
# Now we have our good server settings in "server_settings"
739
debug = server_settings["debug"]
742
syslogger.setLevel(logging.WARNING)
743
console.setLevel(logging.WARNING)
745
if server_settings["servicename"] != "Mandos":
746
syslogger.setFormatter(logging.Formatter\
747
('Mandos (%s): %%(levelname)s:'
749
% server_settings["servicename"]))
713
751
# Parse config file with clients
714
752
client_defaults = { "timeout": "1h",
715
753
"interval": "5m",
716
"checker": "fping -q -- %%(fqdn)s",
754
"checker": "fping -q -- %(host)s",
718
757
client_config = ConfigParser.SafeConfigParser(client_defaults)
719
758
client_config.read(os.path.join(server_settings["configdir"],
723
762
service = AvahiService(name = server_settings["servicename"],
724
763
type = "_mandos._tcp", );
725
764
if server_settings["interface"]:
726
service.interface = if_nametoindex(server_settings["interface"])
765
service.interface = if_nametoindex\
766
(server_settings["interface"])
732
772
DBusGMainLoop(set_as_default=True )
733
773
main_loop = gobject.MainLoop()
734
774
bus = dbus.SystemBus()
735
server = dbus.Interface(
736
bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
737
avahi.DBUS_INTERFACE_SERVER )
775
server = dbus.Interface(bus.get_object(avahi.DBUS_NAME,
776
avahi.DBUS_PATH_SERVER),
777
avahi.DBUS_INTERFACE_SERVER)
738
778
# 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)
751
781
def remove_from_clients(client):
752
782
clients.remove(client)
754
logger.debug(u"No clients left, exiting")
784
logger.critical(u"No clients left, exiting")
757
clients.update(Set(Client(name=section,
787
clients.update(Set(Client(name = section,
758
788
stop_hook = remove_from_clients,
759
**(dict(client_config\
790
= dict(client_config.items(section)))
761
791
for section in client_config.sections()))
793
logger.critical(u"No clients defined")
797
# Redirect stdin so all checkers get /dev/null
798
null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
799
os.dup2(null, sys.stdin.fileno())
804
logger.removeHandler(console)
805
# Close all input and output, do double fork, etc.
808
pidfilename = "/var/run/mandos/mandos.pid"
811
pidfile = open(pidfilename, "w")
812
pidfile.write(str(pid) + "\n")
816
logger.error(u"Could not write %s file with PID %d",
817
pidfilename, os.getpid())
767
820
"Cleanup function; run on exit"
795
848
# Find out what port we got
796
849
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())
850
logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
851
u" scope_id %d" % tcp_server.socket.getsockname())
800
853
#service.interface = tcp_server.socket.getsockname()[3]