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
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# Contact the authors at <mandos@fukt.bsnet.se>.
62
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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.
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
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self.rename_count += 1
151
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avahi.DBUS_INTERFACE_ENTRY_GROUP)
152
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group.connect_to_signal('StateChanged',
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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
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service.name, service.type)
156
156
group.AddService(
157
157
self.interface, # interface
175
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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
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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))
531
509
"""This overrides the normal server_bind() function
532
510
to bind to an interface if one was specified, and also NOT to
533
511
bind to an address or port if they were not specified."""
534
if self.settings["interface"]:
512
if self.settings["interface"] != avahi.IF_UNSPEC:
535
513
# 25 is from /usr/include/asm-i486/socket.h
536
514
SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
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
702
if not server_settings["interface"]:
703
server_settings["interface"] = avahi.IF_UNSPEC
729
705
# Override the settings from the config file with command line
730
706
# options, if set.
737
713
# 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
715
# Parse config file with clients
752
716
client_defaults = { "timeout": "1h",
753
717
"interval": "5m",
754
"checker": "fping -q -- %(host)s",
718
"checker": "fping -q -- %%(fqdn)s",
757
720
client_config = ConfigParser.SafeConfigParser(client_defaults)
758
721
client_config.read(os.path.join(server_settings["configdir"],
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 port %d", service.port)
853
#service.interface = tcp_server.socket.getsockname()[3]
799
if not server_settings["interface"]:
800
service.interface = if_nametoindex\
801
(server_settings["interface"])
856
804
# From the Avahi example code