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
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
28
# <http://www.gnu.org/licenses/>.
27
# along with this program. If not, see <http://www.gnu.org/licenses/>.
30
29
# Contact the authors at <mandos@fukt.bsnet.se>.
62
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.
67
76
logger = logging.Logger('mandos')
68
77
syslogger = logging.handlers.SysLogHandler\
69
(facility = logging.handlers.SysLogHandler.LOG_DAEMON,
78
(facility = logging.handlers.SysLogHandler.LOG_DAEMON)
71
79
syslogger.setFormatter(logging.Formatter\
72
('Mandos: %(levelname)s: %(message)s'))
80
('%(levelname)s: %(message)s'))
73
81
logger.addHandler(syslogger)
75
console = logging.StreamHandler()
76
console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
78
logger.addHandler(console)
80
85
class AvahiError(Exception):
81
86
def __init__(self, value):
93
98
class AvahiService(object):
94
"""An Avahi (Zeroconf) service.
96
100
interface: integer; avahi.IF_UNSPEC or an interface index.
97
101
Used to optionally bind to the specified interface.
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
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
109
114
def __init__(self, interface = avahi.IF_UNSPEC, name = None,
110
115
type = None, port = None, TXT = None, domain = "",
111
host = "", max_renames = 32768):
116
host = "", max_renames = 12):
117
"""An Avahi (Zeroconf) service. """
112
118
self.interface = interface
120
126
self.domain = domain
122
128
self.rename_count = 0
123
self.max_renames = max_renames
124
129
def rename(self):
125
130
"""Derived from the Avahi example code"""
126
131
if self.rename_count >= self.max_renames:
127
logger.critical(u"No suitable Zeroconf service name found"
128
u" after %i retries, exiting.",
132
logger.critical(u"No suitable service name found after %i"
133
u" retries, exiting.", rename_count)
130
134
raise AvahiServiceError("Too many renames")
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))
135
name = server.GetAlternativeServiceName(name)
136
logger.notice(u"Changing name to %r ...", name)
139
139
self.rename_count += 1
151
151
avahi.DBUS_INTERFACE_ENTRY_GROUP)
152
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group.connect_to_signal('StateChanged',
153
153
entry_group_state_changed)
154
logger.debug(u"Adding Zeroconf service '%s' of type '%s' ...",
154
logger.debug(u"Adding 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
host: string; available for use by the checker command
178
fqdn: string (FQDN); 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, config={}):
225
"""Note: the 'checker' key in 'config' sets the
226
'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.."""
229
230
logger.debug(u"Creating client %r", self.name)
230
# Uppercase and remove spaces from fingerprint for later
231
# comparison purposes with return value from the fingerprint()
233
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"")
235
235
logger.debug(u" Fingerprint: %s", self.fingerprint)
236
if "secret" in config:
237
self.secret = config["secret"].decode(u"base64")
238
elif "secfile" in config:
239
sf = open(config["secfile"])
237
self.secret = secret.decode(u"base64")
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(config["timeout"])
249
self.interval = string_to_delta(config["interval"])
248
self.timeout = string_to_delta(timeout)
249
self.interval = string_to_delta(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 = config["checker"]
255
self.check_command = 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.
274
if hasattr(self, "secret") and self.secret:
275
logger.info(u"Stopping client %s", self.name)
275
logger.debug(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.info(u"Checker for %(name)s succeeded",
300
logger.debug(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.info(u"Checker for %(name)s failed",
311
logger.debug(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.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.)
341
logger.debug(u"Starting checker %r for %s",
347
343
self.checker = subprocess.Popen(command,
349
345
shell=True, cwd="/")
350
346
self.checker_callback_tag = gobject.child_watch_add\
351
347
(self.checker.pid,
352
348
self.checker_callback)
353
except OSError, error:
349
except subprocess.OSError, error:
354
350
logger.error(u"Failed to start subprocess: %s",
356
352
# Re-run this periodically if run by gobject.timeout_add
362
358
self.checker_callback_tag = None
363
359
if getattr(self, "checker", None) is None:
365
logger.debug(u"Stopping checker for %(name)s", vars(self))
361
logger.debug("Stopping checker for %(name)s", vars(self))
367
363
os.kill(self.checker.pid, signal.SIGTERM)
401
397
def fingerprint(openpgp):
402
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\
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\
412
408
# Import the OpenPGP public key into the certificate
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")
409
ret = gnutls.library.functions.gnutls_openpgp_crt_import\
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
423
413
# New buffer for the fingerprint
424
414
buffer = ctypes.create_string_buffer(20)
425
415
buffer_length = ctypes.c_size_t()
441
431
Note: This will run in its own forked process."""
443
433
def handle(self):
444
logger.info(u"TCP connection from: %s",
434
logger.debug(u"TCP connection from: %s",
445
435
unicode(self.client_address))
446
436
session = gnutls.connection.ClientSession\
447
437
(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)
458
438
# Note: gnutls.connection.X509Credentials is really a generic
459
439
# GnuTLS certificate credentials object so long as no X.509
460
440
# keys are added to it. Therefore, we can use it here despite
474
454
session.handshake()
475
455
except gnutls.errors.GNUTLSError, error:
476
logger.warning(u"Handshake failed: %s", error)
456
logger.debug(u"Handshake failed: %s", error)
477
457
# Do not run session.bye() here: the session is not
478
458
# established. Just abandon the request.
481
461
fpr = fingerprint(peer_certificate(session))
482
462
except (TypeError, gnutls.errors.GNUTLSError), error:
483
logger.warning(u"Bad certificate: %s", error)
463
logger.debug(u"Bad certificate: %s", error)
486
466
logger.debug(u"Fingerprint: %s", fpr)
493
logger.warning(u"Client not found for fingerprint: %s",
473
logger.debug(u"Client not found for fingerprint: %s", fpr)
497
476
# Have to check if client.still_valid(), since it is possible
498
477
# that the client timed out while establishing the GnuTLS
500
479
if not client.still_valid():
501
logger.warning(u"Client %(name)s is invalid",
480
logger.debug(u"Client %(name)s is invalid", vars(client))
540
518
self.settings["interface"])
541
519
except socket.error, error:
542
520
if error[0] == errno.EPERM:
543
logger.error(u"No permission to"
544
u" bind to interface %s",
545
self.settings["interface"])
521
logger.warning(u"No permission to"
522
u" bind to interface %s",
523
self.settings["interface"])
548
526
# Only bind(2) the socket if we really need to.
551
529
in6addr_any = "::"
552
530
self.server_address = (in6addr_any,
553
531
self.server_address[1])
554
elif not self.server_address[1]:
532
elif self.server_address[1] is None:
555
533
self.server_address = (self.server_address[0],
557
# if self.settings["interface"]:
558
# self.server_address = (self.server_address[0],
564
535
return super(type(self), self).server_bind()
577
548
datetime.timedelta(1)
578
549
>>> string_to_delta(u'1w')
579
550
datetime.timedelta(7)
580
>>> string_to_delta('5m 30s')
581
datetime.timedelta(0, 330)
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):
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)
567
except (ValueError, IndexError):
606
572
def server_state_changed(state):
607
573
"""Derived from the Avahi example code"""
608
574
if state == avahi.SERVER_COLLISION:
609
logger.error(u"Zeroconf server name collision")
575
logger.warning(u"Server name collision")
611
577
elif state == avahi.SERVER_RUNNING:
615
581
def entry_group_state_changed(state, error):
616
582
"""Derived from the Avahi example code"""
617
logger.debug(u"Avahi state change: %i", state)
583
logger.debug(u"state change: %i", state)
619
585
if state == avahi.ENTRY_GROUP_ESTABLISHED:
620
logger.debug(u"Zeroconf service established.")
586
logger.debug(u"Service established.")
621
587
elif state == avahi.ENTRY_GROUP_COLLISION:
622
logger.warning(u"Zeroconf service name collision.")
588
logger.warning(u"Service name collision.")
624
590
elif state == avahi.ENTRY_GROUP_FAILURE:
625
logger.critical(u"Avahi: Error in group state changed %s",
591
logger.critical(u"Error in group state changed %s",
627
593
raise AvahiGroupError("State changed: %s", str(error))
629
def if_nametoindex(interface):
595
def if_nametoindex(interface, _func=[None]):
630
596
"""Call the C function if_nametoindex(), or equivalent"""
631
global if_nametoindex
597
if _func[0] is not None:
598
return _func[0](interface)
633
600
if "ctypes.util" not in sys.modules:
634
601
import ctypes.util
635
if_nametoindex = ctypes.cdll.LoadLibrary\
636
(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)
637
611
except (OSError, AttributeError):
638
612
if "struct" not in sys.modules:
640
614
if "fcntl" not in sys.modules:
642
def if_nametoindex(interface):
616
def the_hard_way(interface):
643
617
"Get an interface index the hard way, i.e. using fcntl()"
644
618
SIOCGIFINDEX = 0x8933 # From /usr/include/linux/sockios.h
645
619
s = socket.socket()
649
623
interface_index = struct.unpack("I", ifreq[16:20])[0]
650
624
return interface_index
651
return if_nametoindex(interface)
654
def daemon(nochdir = False, noclose = False):
625
_func[0] = the_hard_way
626
return _func[0](interface)
629
def daemon(nochdir, noclose):
655
630
"""See daemon(3). Standard BSD Unix function.
656
631
This should really exist as os.daemon, but it doesn't (yet)."""
678
651
global main_loop_started
679
652
main_loop_started = False
681
parser = OptionParser(version = "%%prog %s" % version)
654
parser = OptionParser()
682
655
parser.add_option("-i", "--interface", type="string",
683
656
metavar="IF", help="Bind to interface IF")
684
657
parser.add_option("-a", "--address", type="string",
687
660
help="Port number to receive requests on")
688
661
parser.add_option("--check", action="store_true", default=False,
689
662
help="Run self-test")
690
parser.add_option("--debug", action="store_true",
663
parser.add_option("--debug", action="store_true", default=False,
691
664
help="Debug mode; run in foreground and log to"
693
666
parser.add_option("--priority", type="string", help="GnuTLS"
718
691
# Parse config file for server-global settings
719
692
server_config = ConfigParser.SafeConfigParser(server_defaults)
720
693
del server_defaults
721
server_config.read(os.path.join(options.configdir, "mandos.conf"))
694
server_config.read(os.path.join(options.configdir, "server.conf"))
695
server_section = "server"
722
696
# Convert the SafeConfigParser object to a dict
723
server_settings = server_config.defaults()
697
server_settings = dict(server_config.items(server_section))
724
698
# Use getboolean on the boolean config option
725
699
server_settings["debug"] = server_config.getboolean\
700
(server_section, "debug")
727
701
del server_config
729
703
# Override the settings from the config file with command line
737
711
# 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"]))
751
713
# Parse config file with clients
752
714
client_defaults = { "timeout": "1h",
753
715
"interval": "5m",
754
"checker": "fping -q -- %(host)s",
716
"checker": "fping -q -- %%(fqdn)s",
757
718
client_config = ConfigParser.SafeConfigParser(client_defaults)
758
719
client_config.read(os.path.join(server_settings["configdir"],
762
723
service = AvahiService(name = server_settings["servicename"],
763
724
type = "_mandos._tcp", );
764
725
if server_settings["interface"]:
765
service.interface = if_nametoindex\
766
(server_settings["interface"])
726
service.interface = if_nametoindex(server_settings["interface"])
772
732
DBusGMainLoop(set_as_default=True )
773
733
main_loop = gobject.MainLoop()
774
734
bus = dbus.SystemBus()
775
server = dbus.Interface(bus.get_object(avahi.DBUS_NAME,
776
avahi.DBUS_PATH_SERVER),
777
avahi.DBUS_INTERFACE_SERVER)
735
server = dbus.Interface(
736
bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
737
avahi.DBUS_INTERFACE_SERVER )
778
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)
781
751
def remove_from_clients(client):
782
752
clients.remove(client)
784
logger.critical(u"No clients left, exiting")
754
logger.debug(u"No clients left, exiting")
787
clients.update(Set(Client(name = section,
757
clients.update(Set(Client(name=section,
788
758
stop_hook = remove_from_clients,
790
= dict(client_config.items(section)))
759
**(dict(client_config\
791
761
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())
820
767
"Cleanup function; run on exit"
848
795
# Find out what port we got
849
796
service.port = tcp_server.socket.getsockname()[1]
850
logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
851
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())
853
800
#service.interface = tcp_server.socket.getsockname()[3]