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
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# methods "add" and "remove" in the "AvahiService" class, the
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# "server_state_changed" and "entry_group_state_changed" functions,
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# and some lines in "main".
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# following functions: "AvahiService.add", "AvahiService.remove",
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# "server_state_changed", "entry_group_state_changed", and some lines
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# Everything else is
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# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
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from dbus.mainloop.glib import DBusGMainLoop
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# 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\
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('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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class AvahiError(Exception):
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def __init__(self, value):
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class AvahiService(object):
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"""An Avahi (Zeroconf) service.
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interface: integer; avahi.IF_UNSPEC or an interface index.
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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'.
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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
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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
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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 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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type = None, port = None, TXT = None, domain = "",
110
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 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 name to %r ...", str(self.name))
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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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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
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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'
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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()
230
self.fingerprint = config["fingerprint"].upper()\
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# Uppercase and remove spaces from fingerprint
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# 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:
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self.secret = config["secret"].decode(u"base64")
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elif "secfile" in config:
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sf = open(config["secfile"])
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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"
242
self.host = config.get("host", "")
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self.created = datetime.datetime.now()
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self.last_checked_ok = None
245
self.timeout = string_to_delta(config["timeout"])
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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
251
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self.checker_callback_tag = None
252
self.check_command = config["checker"]
255
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.
271
if hasattr(self, "secret") and self.secret:
272
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
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if os.WIFEXITED(condition) \
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and (os.WEXITSTATUS(condition) == 0):
297
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?",
308
logger.info(u"Checker for %(name)s failed",
311
logger.debug(u"Checker for %(name)s failed",
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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
338
logger.info(u"Starting checker %r for %s",
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# We don't need to redirect stdout and stderr, since
341
# in normal mode, that is already done by daemon(),
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# and in debug mode we don't want to. (Stdin is
343
# always replaced by /dev/null.)
341
logger.debug(u"Starting checker %r for %s",
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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,
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self.checker_callback)
350
except OSError, error:
349
except subprocess.OSError, error:
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logger.error(u"Failed to start subprocess: %s",
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# Re-run this periodically if run by gobject.timeout_add
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self.checker_callback_tag = None
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if getattr(self, "checker", None) is None:
362
logger.debug(u"Stopping checker for %(name)s", vars(self))
361
logger.debug("Stopping checker for %(name)s", vars(self))
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os.kill(self.checker.pid, signal.SIGTERM)
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def fingerprint(openpgp):
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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\
400
403
# New GnuTLS "datum" with the OpenPGP public key
401
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datum = gnutls.library.types.gnutls_datum_t\
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405
(ctypes.cast(ctypes.c_char_p(openpgp),
403
406
ctypes.POINTER(ctypes.c_ubyte)),
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ctypes.c_uint(len(openpgp)))
405
# New empty GnuTLS certificate
406
crt = gnutls.library.types.gnutls_openpgp_crt_t()
407
gnutls.library.functions.gnutls_openpgp_crt_init\
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# Import the OpenPGP public key into the certificate
410
gnutls.library.functions.gnutls_openpgp_crt_import\
411
(crt, ctypes.byref(datum),
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
409
ret = gnutls.library.functions.gnutls_openpgp_crt_import\
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
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# New buffer for the fingerprint
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buffer = ctypes.create_string_buffer(20)
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buffer_length = ctypes.c_size_t()
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Note: This will run in its own forked process."""
433
433
def handle(self):
434
logger.info(u"TCP connection from: %s",
434
logger.debug(u"TCP connection from: %s",
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435
unicode(self.client_address))
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session = gnutls.connection.ClientSession\
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(self.request, gnutls.connection.X509Credentials())
439
line = self.request.makefile().readline()
440
logger.debug(u"Protocol version: %r", line)
442
if int(line.strip().split()[0]) > 1:
444
except (ValueError, IndexError, RuntimeError), error:
445
logger.error(u"Unknown protocol version: %s", error)
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# Note: gnutls.connection.X509Credentials is really a generic
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# GnuTLS certificate credentials object so long as no X.509
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# keys are added to it. Therefore, we can use it here despite
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session.handshake()
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except gnutls.errors.GNUTLSError, error:
466
logger.warning(u"Handshake failed: %s", error)
456
logger.debug(u"Handshake failed: %s", error)
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# Do not run session.bye() here: the session is not
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# established. Just abandon the request.
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fpr = fingerprint(peer_certificate(session))
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except (TypeError, gnutls.errors.GNUTLSError), error:
473
logger.warning(u"Bad certificate: %s", error)
463
logger.debug(u"Bad certificate: %s", error)
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466
logger.debug(u"Fingerprint: %s", fpr)
483
logger.warning(u"Client not found for fingerprint: %s",
473
logger.debug(u"Client not found for fingerprint: %s", fpr)
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# Have to check if client.still_valid(), since it is possible
488
477
# that the client timed out while establishing the GnuTLS
490
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if not client.still_valid():
491
logger.warning(u"Client %(name)s is invalid",
480
logger.debug(u"Client %(name)s is invalid", vars(client))
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"""This overrides the normal server_bind() function
522
510
to bind to an interface if one was specified, and also NOT to
523
511
bind to an address or port if they were not specified."""
524
if self.settings["interface"]:
512
if self.settings["interface"] != avahi.IF_UNSPEC:
525
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# 25 is from /usr/include/asm-i486/socket.h
526
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SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
530
518
self.settings["interface"])
531
519
except socket.error, error:
532
520
if error[0] == errno.EPERM:
533
logger.error(u"No permission to"
534
u" bind to interface %s",
535
self.settings["interface"])
521
logger.warning(u"No permission to"
522
u" bind to interface %s",
523
self.settings["interface"])
538
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# Only bind(2) the socket if we really need to.
541
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in6addr_any = "::"
542
530
self.server_address = (in6addr_any,
543
531
self.server_address[1])
544
elif not self.server_address[1]:
532
elif self.server_address[1] is None:
545
533
self.server_address = (self.server_address[0],
547
# if self.settings["interface"]:
548
# self.server_address = (self.server_address[0],
554
535
return super(type(self), self).server_bind()
567
548
datetime.timedelta(1)
568
549
>>> string_to_delta(u'1w')
569
550
datetime.timedelta(7)
570
>>> string_to_delta('5m 30s')
571
datetime.timedelta(0, 330)
573
timevalue = datetime.timedelta(0)
574
for s in interval.split():
576
suffix=unicode(s[-1])
579
delta = datetime.timedelta(value)
581
delta = datetime.timedelta(0, value)
583
delta = datetime.timedelta(0, 0, 0, 0, value)
585
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
587
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
590
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):
596
572
def server_state_changed(state):
597
573
"""Derived from the Avahi example code"""
598
574
if state == avahi.SERVER_COLLISION:
599
logger.error(u"Server name collision")
575
logger.warning(u"Server name collision")
601
577
elif state == avahi.SERVER_RUNNING:
617
593
raise AvahiGroupError("State changed: %s", str(error))
619
def if_nametoindex(interface):
595
def if_nametoindex(interface, _func=[None]):
620
596
"""Call the C function if_nametoindex(), or equivalent"""
621
global if_nametoindex
597
if _func[0] is not None:
598
return _func[0](interface)
623
600
if "ctypes.util" not in sys.modules:
624
601
import ctypes.util
625
if_nametoindex = ctypes.cdll.LoadLibrary\
626
(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)
627
611
except (OSError, AttributeError):
628
612
if "struct" not in sys.modules:
630
614
if "fcntl" not in sys.modules:
632
def if_nametoindex(interface):
616
def the_hard_way(interface):
633
617
"Get an interface index the hard way, i.e. using fcntl()"
634
618
SIOCGIFINDEX = 0x8933 # From /usr/include/linux/sockios.h
635
619
s = socket.socket()
639
623
interface_index = struct.unpack("I", ifreq[16:20])[0]
640
624
return interface_index
641
return if_nametoindex(interface)
644
def daemon(nochdir = False, noclose = False):
625
_func[0] = the_hard_way
626
return _func[0](interface)
629
def daemon(nochdir, noclose):
645
630
"""See daemon(3). Standard BSD Unix function.
646
631
This should really exist as os.daemon, but it doesn't (yet)."""
668
651
global main_loop_started
669
652
main_loop_started = False
671
parser = OptionParser(version = "%%prog %s" % version)
654
parser = OptionParser()
672
655
parser.add_option("-i", "--interface", type="string",
673
656
metavar="IF", help="Bind to interface IF")
674
657
parser.add_option("-a", "--address", type="string",
677
660
help="Port number to receive requests on")
678
661
parser.add_option("--check", action="store_true", default=False,
679
662
help="Run self-test")
680
parser.add_option("--debug", action="store_true",
663
parser.add_option("--debug", action="store_true", default=False,
681
664
help="Debug mode; run in foreground and log to"
683
666
parser.add_option("--priority", type="string", help="GnuTLS"
708
691
# Parse config file for server-global settings
709
692
server_config = ConfigParser.SafeConfigParser(server_defaults)
710
693
del server_defaults
711
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"
712
696
# Convert the SafeConfigParser object to a dict
713
server_settings = server_config.defaults()
697
server_settings = dict(server_config.items(server_section))
714
698
# Use getboolean on the boolean config option
715
699
server_settings["debug"] = server_config.getboolean\
700
(server_section, "debug")
717
701
del server_config
702
if not server_settings["interface"]:
703
server_settings["interface"] = avahi.IF_UNSPEC
719
705
# Override the settings from the config file with command line
720
706
# options, if set.
727
713
# Now we have our good server settings in "server_settings"
729
debug = server_settings["debug"]
732
syslogger.setLevel(logging.WARNING)
733
console.setLevel(logging.WARNING)
735
if server_settings["servicename"] != "Mandos":
736
syslogger.setFormatter(logging.Formatter\
737
('Mandos (%s): %%(levelname)s:'
739
% server_settings["servicename"]))
741
715
# Parse config file with clients
742
716
client_defaults = { "timeout": "1h",
743
717
"interval": "5m",
744
"checker": "fping -q -- %(host)s",
718
"checker": "fping -q -- %%(fqdn)s",
747
720
client_config = ConfigParser.SafeConfigParser(client_defaults)
748
721
client_config.read(os.path.join(server_settings["configdir"],
766
737
avahi.DBUS_INTERFACE_SERVER )
767
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)
770
751
def remove_from_clients(client):
771
752
clients.remove(client)
773
logger.critical(u"No clients left, exiting")
754
logger.debug(u"No clients left, exiting")
776
clients.update(Set(Client(name = section,
757
clients.update(Set(Client(name=section,
777
758
stop_hook = remove_from_clients,
779
= dict(client_config.items(section)))
759
**(dict(client_config\
780
761
for section in client_config.sections()))
782
logger.critical(u"No clients defined")
786
# Redirect stdin so all checkers get /dev/null
787
null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
788
os.dup2(null, sys.stdin.fileno())
793
logger.removeHandler(console)
794
# Close all input and output, do double fork, etc.
797
pidfilename = "/var/run/mandos/mandos.pid"
800
pidfile = open(pidfilename, "w")
801
pidfile.write(str(pid) + "\n")
805
logger.error(u"Could not write %s file with PID %d",
806
pidfilename, os.getpid())
809
767
"Cleanup function; run on exit"
837
795
# Find out what port we got
838
796
service.port = tcp_server.socket.getsockname()[1]
839
logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
840
u" scope_id %d" % tcp_server.socket.getsockname())
797
logger.debug(u"Now listening on port %d", service.port)
842
#service.interface = tcp_server.socket.getsockname()[3]
799
if not server_settings["interface"]:
800
service.interface = if_nametoindex\
801
(server_settings["interface"])
845
804
# From the Avahi example code