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
# Copyright © 2008 Teddy Hogeborn & Björn Påhlsson
14
# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
16
16
# This program is free software: you can redistribute it and/or modify
17
17
# it under the terms of the GNU General Public License as published by
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/>.
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# Contact the authors at <mandos@fukt.bsnet.se>.
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61
from dbus.mainloop.glib import DBusGMainLoop
64
# Brief description of the operation of this program:
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# This server announces itself as a Zeroconf service. Connecting
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# clients use the TLS protocol, with the unusual quirk that this
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# server program acts as a TLS "client" while a connecting client acts
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# as a TLS "server". The client (acting as a TLS "server") must
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# supply an OpenPGP certificate, and the fingerprint of this
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# certificate is used by this server to look up (in a list read from a
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# file at start time) which binary blob to give the client. No other
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# authentication or authorization is done by this server.
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logger = logging.Logger('mandos')
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syslogger = logging.handlers.SysLogHandler\
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(facility = logging.handlers.SysLogHandler.LOG_DAEMON,
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(facility = logging.handlers.SysLogHandler.LOG_DAEMON)
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syslogger.setFormatter(logging.Formatter\
73
('Mandos: %(levelname)s: %(message)s'))
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('%(levelname)s: %(message)s'))
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logger.addHandler(syslogger)
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console = logging.StreamHandler()
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console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
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logger.addHandler(console)
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85
class AvahiError(Exception):
82
86
def __init__(self, value):
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98
class AvahiService(object):
95
"""An Avahi (Zeroconf) service.
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interface: integer; avahi.IF_UNSPEC or an interface index.
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101
Used to optionally bind to the specified interface.
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name: string; Example: 'Mandos'
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type: string; Example: '_mandos._tcp'.
101
See <http://www.dns-sd.org/ServiceTypes.html>
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port: integer; what port to announce
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TXT: list of strings; TXT record for the service
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domain: string; Domain to publish on, default to .local if empty.
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host: string; Host to publish records for, default is localhost
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max_renames: integer; maximum number of renames
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rename_count: integer; counter so we only rename after collisions
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a sensible number of times
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name = string; Example: "Mandos"
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type = string; Example: "_mandos._tcp".
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See <http://www.dns-sd.org/ServiceTypes.html>
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port = integer; what port to announce
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TXT = list of strings; TXT record for the service
107
domain = string; Domain to publish on, default to .local if empty.
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host = string; Host to publish records for, default to localhost
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max_renames = integer; maximum number of renames
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rename_count = integer; counter so we only rename after collisions
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a sensible number of times
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def __init__(self, interface = avahi.IF_UNSPEC, name = None,
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115
type = None, port = None, TXT = None, domain = "",
112
host = "", max_renames = 32768):
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host = "", max_renames = 12):
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"""An Avahi (Zeroconf) service. """
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self.interface = interface
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self.domain = domain
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self.rename_count = 0
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self.max_renames = max_renames
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def rename(self):
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"""Derived from the Avahi example code"""
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if self.rename_count >= self.max_renames:
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logger.critical(u"No suitable Zeroconf service name found"
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u" after %i retries, exiting.",
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logger.critical(u"No suitable service name found after %i"
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u" retries, exiting.", rename_count)
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raise AvahiServiceError("Too many renames")
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self.name = server.GetAlternativeServiceName(self.name)
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logger.info(u"Changing Zeroconf service name to %r ...",
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syslogger.setFormatter(logging.Formatter\
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('Mandos (%s): %%(levelname)s:'
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' %%(message)s' % self.name))
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name = server.GetAlternativeServiceName(name)
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logger.notice(u"Changing name to %r ...", name)
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self.rename_count += 1
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avahi.DBUS_INTERFACE_ENTRY_GROUP)
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group.connect_to_signal('StateChanged',
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entry_group_state_changed)
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logger.debug(u"Adding Zeroconf service '%s' of type '%s' ...",
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logger.debug(u"Adding service '%s' of type '%s' ...",
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service.name, service.type)
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group.AddService(
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self.interface, # interface
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fingerprint: string (40 or 32 hexadecimal digits); used to
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uniquely identify the client
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secret: bytestring; sent verbatim (over TLS) to client
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host: string; available for use by the checker command
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fqdn: string (FQDN); available for use by the checker command
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created: datetime.datetime(); object creation, not client host
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last_checked_ok: datetime.datetime() or None if not yet checked OK
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timeout: datetime.timedelta(); How long from last_checked_ok
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interval = property(lambda self: self._interval,
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del _set_interval
225
def __init__(self, name = None, stop_hook=None, config={}):
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"""Note: the 'checker' key in 'config' sets the
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'checker_command' attribute and *not* the 'checker'
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def __init__(self, name=None, stop_hook=None, fingerprint=None,
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secret=None, secfile=None, fqdn=None, timeout=None,
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interval=-1, checker=None):
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"""Note: the 'checker' argument sets the 'checker_command'
228
attribute and not the 'checker' attribute.."""
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logger.debug(u"Creating client %r", self.name)
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# Uppercase and remove spaces from fingerprint for later
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# comparison purposes with return value from the fingerprint()
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self.fingerprint = config["fingerprint"].upper()\
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# Uppercase and remove spaces from fingerprint
232
# for later comparison purposes with return value of
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# the fingerprint() function
234
self.fingerprint = fingerprint.upper().replace(u" ", u"")
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logger.debug(u" Fingerprint: %s", self.fingerprint)
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if "secret" in config:
238
self.secret = config["secret"].decode(u"base64")
239
elif "secfile" in config:
240
sf = open(config["secfile"])
237
self.secret = secret.decode(u"base64")
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self.secret = sf.read()
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raise TypeError(u"No secret or secfile for client %s"
246
self.host = config.get("host", "")
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self.created = datetime.datetime.now()
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self.last_checked_ok = None
249
self.timeout = string_to_delta(config["timeout"])
250
self.interval = string_to_delta(config["interval"])
248
self.timeout = string_to_delta(timeout)
249
self.interval = string_to_delta(interval)
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self.stop_hook = stop_hook
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self.checker = None
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self.checker_initiator_tag = None
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self.stop_initiator_tag = None
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self.checker_callback_tag = None
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self.check_command = config["checker"]
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self.check_command = checker
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"""Start this client's checker and timeout hooks"""
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# Schedule a new checker to be started an 'interval' from now,
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The possibility that a client might be restarted is left open,
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but not currently used."""
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# If this client doesn't have a secret, it is already stopped.
275
if hasattr(self, "secret") and self.secret:
276
logger.info(u"Stopping client %s", self.name)
275
logger.debug(u"Stopping client %s", self.name)
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self.secret = None
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self.checker = None
299
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if os.WIFEXITED(condition) \
300
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and (os.WEXITSTATUS(condition) == 0):
301
logger.info(u"Checker for %(name)s succeeded",
300
logger.debug(u"Checker for %(name)s succeeded",
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self.last_checked_ok = now
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gobject.source_remove(self.stop_initiator_tag)
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self.stop_initiator_tag = gobject.timeout_add\
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logger.warning(u"Checker for %(name)s crashed?",
312
logger.info(u"Checker for %(name)s failed",
311
logger.debug(u"Checker for %(name)s failed",
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313
def start_checker(self):
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"""Start a new checker subprocess if one is not running.
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If a checker already exists, leave it running and do
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u' %s', self.check_command, error)
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return True # Try again later
342
logger.info(u"Starting checker %r for %s",
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# 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.)
341
logger.debug(u"Starting checker %r for %s",
348
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self.checker = subprocess.Popen(command,
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shell=True, cwd="/")
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self.checker_callback_tag = gobject.child_watch_add\
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(self.checker.pid,
353
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self.checker_callback)
354
except OSError, error:
349
except subprocess.OSError, error:
355
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logger.error(u"Failed to start subprocess: %s",
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352
# Re-run this periodically if run by gobject.timeout_add
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358
self.checker_callback_tag = None
364
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if getattr(self, "checker", None) is None:
366
logger.debug(u"Stopping checker for %(name)s", vars(self))
361
logger.debug("Stopping checker for %(name)s", vars(self))
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363
os.kill(self.checker.pid, signal.SIGTERM)
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397
def fingerprint(openpgp):
403
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"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\
404
403
# New GnuTLS "datum" with the OpenPGP public key
405
404
datum = gnutls.library.types.gnutls_datum_t\
406
405
(ctypes.cast(ctypes.c_char_p(openpgp),
407
406
ctypes.POINTER(ctypes.c_ubyte)),
408
407
ctypes.c_uint(len(openpgp)))
409
# New empty GnuTLS certificate
410
crt = gnutls.library.types.gnutls_openpgp_crt_t()
411
gnutls.library.functions.gnutls_openpgp_crt_init\
413
408
# Import the OpenPGP public key into the certificate
414
gnutls.library.functions.gnutls_openpgp_crt_import\
415
(crt, ctypes.byref(datum),
416
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")
409
ret = gnutls.library.functions.gnutls_openpgp_crt_import\
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
424
413
# New buffer for the fingerprint
425
414
buffer = ctypes.create_string_buffer(20)
426
415
buffer_length = ctypes.c_size_t()
442
431
Note: This will run in its own forked process."""
444
433
def handle(self):
445
logger.info(u"TCP connection from: %s",
434
logger.debug(u"TCP connection from: %s",
446
435
unicode(self.client_address))
447
436
session = gnutls.connection.ClientSession\
448
437
(self.request, gnutls.connection.X509Credentials())
450
line = self.request.makefile().readline()
451
logger.debug(u"Protocol version: %r", line)
453
if int(line.strip().split()[0]) > 1:
455
except (ValueError, IndexError, RuntimeError), error:
456
logger.error(u"Unknown protocol version: %s", error)
459
438
# Note: gnutls.connection.X509Credentials is really a generic
460
439
# GnuTLS certificate credentials object so long as no X.509
461
440
# keys are added to it. Therefore, we can use it here despite
475
454
session.handshake()
476
455
except gnutls.errors.GNUTLSError, error:
477
logger.warning(u"Handshake failed: %s", error)
456
logger.debug(u"Handshake failed: %s", error)
478
457
# Do not run session.bye() here: the session is not
479
458
# established. Just abandon the request.
482
461
fpr = fingerprint(peer_certificate(session))
483
462
except (TypeError, gnutls.errors.GNUTLSError), error:
484
logger.warning(u"Bad certificate: %s", error)
463
logger.debug(u"Bad certificate: %s", error)
487
466
logger.debug(u"Fingerprint: %s", fpr)
494
logger.warning(u"Client not found for fingerprint: %s",
473
logger.debug(u"Client not found for fingerprint: %s", fpr)
498
476
# Have to check if client.still_valid(), since it is possible
499
477
# that the client timed out while establishing the GnuTLS
501
479
if not client.still_valid():
502
logger.warning(u"Client %(name)s is invalid",
480
logger.debug(u"Client %(name)s is invalid", vars(client))
528
504
if "clients" in kwargs:
529
505
self.clients = kwargs["clients"]
530
506
del kwargs["clients"]
532
507
return super(type(self), self).__init__(*args, **kwargs)
533
508
def server_bind(self):
534
509
"""This overrides the normal server_bind() function
535
510
to bind to an interface if one was specified, and also NOT to
536
511
bind to an address or port if they were not specified."""
537
if self.settings["interface"]:
512
if self.settings["interface"] != avahi.IF_UNSPEC:
538
513
# 25 is from /usr/include/asm-i486/socket.h
539
514
SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
543
518
self.settings["interface"])
544
519
except socket.error, error:
545
520
if error[0] == errno.EPERM:
546
logger.error(u"No permission to"
547
u" bind to interface %s",
548
self.settings["interface"])
521
logger.warning(u"No permission to"
522
u" bind to interface %s",
523
self.settings["interface"])
551
526
# Only bind(2) the socket if we really need to.
554
529
in6addr_any = "::"
555
530
self.server_address = (in6addr_any,
556
531
self.server_address[1])
557
elif not self.server_address[1]:
532
elif self.server_address[1] is None:
558
533
self.server_address = (self.server_address[0],
560
# if self.settings["interface"]:
561
# self.server_address = (self.server_address[0],
567
535
return super(type(self), self).server_bind()
568
def server_activate(self):
570
return super(type(self), self).server_activate()
575
538
def string_to_delta(interval):
585
548
datetime.timedelta(1)
586
549
>>> string_to_delta(u'1w')
587
550
datetime.timedelta(7)
588
>>> string_to_delta('5m 30s')
589
datetime.timedelta(0, 330)
591
timevalue = datetime.timedelta(0)
592
for s in interval.split():
594
suffix=unicode(s[-1])
597
delta = datetime.timedelta(value)
599
delta = datetime.timedelta(0, value)
601
delta = datetime.timedelta(0, 0, 0, 0, value)
603
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
605
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
608
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):
614
572
def server_state_changed(state):
615
573
"""Derived from the Avahi example code"""
616
574
if state == avahi.SERVER_COLLISION:
617
logger.error(u"Zeroconf server name collision")
575
logger.warning(u"Server name collision")
619
577
elif state == avahi.SERVER_RUNNING:
623
581
def entry_group_state_changed(state, error):
624
582
"""Derived from the Avahi example code"""
625
logger.debug(u"Avahi state change: %i", state)
583
logger.debug(u"state change: %i", state)
627
585
if state == avahi.ENTRY_GROUP_ESTABLISHED:
628
logger.debug(u"Zeroconf service established.")
586
logger.debug(u"Service established.")
629
587
elif state == avahi.ENTRY_GROUP_COLLISION:
630
logger.warning(u"Zeroconf service name collision.")
588
logger.warning(u"Service name collision.")
632
590
elif state == avahi.ENTRY_GROUP_FAILURE:
633
logger.critical(u"Avahi: Error in group state changed %s",
591
logger.critical(u"Error in group state changed %s",
635
593
raise AvahiGroupError("State changed: %s", str(error))
637
def if_nametoindex(interface):
595
def if_nametoindex(interface, _func=[None]):
638
596
"""Call the C function if_nametoindex(), or equivalent"""
639
global if_nametoindex
597
if _func[0] is not None:
598
return _func[0](interface)
641
600
if "ctypes.util" not in sys.modules:
642
601
import ctypes.util
643
if_nametoindex = ctypes.cdll.LoadLibrary\
644
(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)
645
611
except (OSError, AttributeError):
646
612
if "struct" not in sys.modules:
648
614
if "fcntl" not in sys.modules:
650
def if_nametoindex(interface):
616
def the_hard_way(interface):
651
617
"Get an interface index the hard way, i.e. using fcntl()"
652
618
SIOCGIFINDEX = 0x8933 # From /usr/include/linux/sockios.h
653
619
s = socket.socket()
657
623
interface_index = struct.unpack("I", ifreq[16:20])[0]
658
624
return interface_index
659
return if_nametoindex(interface)
662
def daemon(nochdir = False, noclose = False):
625
_func[0] = the_hard_way
626
return _func[0](interface)
629
def daemon(nochdir, noclose):
663
630
"""See daemon(3). Standard BSD Unix function.
664
631
This should really exist as os.daemon, but it doesn't (yet)."""
686
651
global main_loop_started
687
652
main_loop_started = False
689
parser = OptionParser(version = "%%prog %s" % version)
654
parser = OptionParser()
690
655
parser.add_option("-i", "--interface", type="string",
691
656
metavar="IF", help="Bind to interface IF")
692
657
parser.add_option("-a", "--address", type="string",
695
660
help="Port number to receive requests on")
696
661
parser.add_option("--check", action="store_true", default=False,
697
662
help="Run self-test")
698
parser.add_option("--debug", action="store_true",
663
parser.add_option("--debug", action="store_true", default=False,
699
664
help="Debug mode; run in foreground and log to"
701
666
parser.add_option("--priority", type="string", help="GnuTLS"
726
691
# Parse config file for server-global settings
727
692
server_config = ConfigParser.SafeConfigParser(server_defaults)
728
693
del server_defaults
729
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"
730
696
# Convert the SafeConfigParser object to a dict
731
server_settings = server_config.defaults()
697
server_settings = dict(server_config.items(server_section))
732
698
# Use getboolean on the boolean config option
733
699
server_settings["debug"] = server_config.getboolean\
700
(server_section, "debug")
735
701
del server_config
702
if not server_settings["interface"]:
703
server_settings["interface"] = avahi.IF_UNSPEC
737
705
# Override the settings from the config file with command line
738
706
# options, if set.
745
713
# Now we have our good server settings in "server_settings"
747
debug = server_settings["debug"]
750
syslogger.setLevel(logging.WARNING)
751
console.setLevel(logging.WARNING)
753
if server_settings["servicename"] != "Mandos":
754
syslogger.setFormatter(logging.Formatter\
755
('Mandos (%s): %%(levelname)s:'
757
% server_settings["servicename"]))
759
715
# Parse config file with clients
760
716
client_defaults = { "timeout": "1h",
761
717
"interval": "5m",
762
"checker": "fping -q -- %(host)s",
718
"checker": "fping -q -- %%(fqdn)s",
765
720
client_config = ConfigParser.SafeConfigParser(client_defaults)
766
721
client_config.read(os.path.join(server_settings["configdir"],
770
tcp_server = IPv6_TCPServer((server_settings["address"],
771
server_settings["port"]),
773
settings=server_settings,
775
pidfilename = "/var/run/mandos.pid"
777
pidfile = open(pidfilename, "w")
778
except IOError, error:
779
logger.error("Could not open file %r", pidfilename)
784
uid = pwd.getpwnam("mandos").pw_uid
787
uid = pwd.getpwnam("nobody").pw_uid
791
gid = pwd.getpwnam("mandos").pw_gid
794
gid = pwd.getpwnam("nogroup").pw_gid
800
except OSError, error:
801
if error[0] != errno.EPERM:
805
725
service = AvahiService(name = server_settings["servicename"],
806
726
type = "_mandos._tcp", );
807
if server_settings["interface"]:
808
service.interface = if_nametoindex\
809
(server_settings["interface"])
815
732
DBusGMainLoop(set_as_default=True )
816
733
main_loop = gobject.MainLoop()
817
734
bus = dbus.SystemBus()
818
server = dbus.Interface(bus.get_object(avahi.DBUS_NAME,
819
avahi.DBUS_PATH_SERVER),
820
avahi.DBUS_INTERFACE_SERVER)
735
server = dbus.Interface(
736
bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
737
avahi.DBUS_INTERFACE_SERVER )
821
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)
823
751
def remove_from_clients(client):
824
752
clients.remove(client)
826
logger.critical(u"No clients left, exiting")
754
logger.debug(u"No clients left, exiting")
829
clients.update(Set(Client(name = section,
757
clients.update(Set(Client(name=section,
830
758
stop_hook = remove_from_clients,
832
= dict(client_config.items(section)))
759
**(dict(client_config\
833
761
for section in client_config.sections()))
835
logger.critical(u"No clients defined")
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())
846
logger.removeHandler(console)
847
# Close all input and output, do double fork, etc.
852
pidfile.write(str(pid) + "\n")
856
logger.error(u"Could not write to file %r with PID %d",
859
# "pidfile" was never created
864
767
"Cleanup function; run on exit"
884
787
for client in clients:
888
tcp_server.server_activate()
790
tcp_server = IPv6_TCPServer((server_settings["address"],
791
server_settings["port"]),
793
settings=server_settings,
890
795
# Find out what port we got
891
796
service.port = tcp_server.socket.getsockname()[1]
892
logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
893
u" scope_id %d" % tcp_server.socket.getsockname())
797
logger.debug(u"Now listening on port %d", service.port)
895
#service.interface = tcp_server.socket.getsockname()[3]
799
if not server_settings["interface"]:
800
service.interface = if_nametoindex\
801
(server_settings["interface"])
898
804
# From the Avahi example code