/mandos/release : revision 24.1.12

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# This program is partly derived from an example program for an Avahi

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# service publisher, downloaded from

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# <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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# in "main".

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#

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# Everything else is

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from dbus.mainloop.glib import DBusGMainLoop

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import ctypes

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version = "1.0"

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# Brief description of the operation of this program:

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#

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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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address = "/dev/log")

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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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del syslogger

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console = logging.StreamHandler()

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console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'

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' %(message)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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Attributes:

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"""

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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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if empty.

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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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"""

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def __init__(self, interface = avahi.IF_UNSPEC, name = None,

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type = None, port = None, TXT = None, domain = "",

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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.name = name

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self.type = type

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self.domain = domain

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self.host = host

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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.remove()

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self.add()

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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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_set_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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attribute."""

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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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self.name = name

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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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# function

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self.fingerprint = config["fingerprint"].upper()\

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.replace(u" ", u"")

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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

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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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if secret:

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self.secret = secret.decode(u"base64")

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elif secfile:

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sf = open(secfile)

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self.secret = sf.read()

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sf.close()

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else:

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raise TypeError(u"No secret or secfile for client %s"

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% self.name)

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self.host = config.get("host", "")

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self.fqdn = fqdn

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self.created = datetime.datetime.now()

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self.last_checked_ok = None

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self.timeout = string_to_delta(config["timeout"])

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self.interval = string_to_delta(config["interval"])

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self.timeout = string_to_delta(timeout)

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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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def start(self):

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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.

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if hasattr(self, "secret") and self.secret:

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logger.info(u"Stopping client %s", self.name)

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if self.secret:

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logger.debug(u"Stopping client %s", self.name)

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self.secret = None

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else:

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return False

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self.checker = None

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if os.WIFEXITED(condition) \

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and (os.WEXITSTATUS(condition) == 0):

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logger.info(u"Checker for %(name)s succeeded",

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vars(self))

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logger.debug(u"Checker for %(name)s succeeded",

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vars(self))

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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?",

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vars(self))

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else:

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logger.info(u"Checker for %(name)s failed",

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vars(self))

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logger.debug(u"Checker for %(name)s failed",

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vars(self))

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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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if self.checker is None:

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try:

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# In case check_command has exactly one % operator

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command = self.check_command % self.host

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command = self.check_command % self.fqdn

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except TypeError:

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# Escape attributes for the shell

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escaped_attrs = dict((key, re.escape(str(val)))

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u' %s', self.check_command, error)

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return True # Try again later

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try:

338

logger.info(u"Starting checker %r for %s",

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command, self.name)

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# We don't need to redirect stdout and stderr, since

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# in normal mode, that is already done by daemon(),

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# and in debug mode we don't want to. (Stdin is

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# always replaced by /dev/null.)

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logger.debug(u"Starting checker %r for %s",

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command, self.name)

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self.checker = subprocess.Popen(command,

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close_fds=True,

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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)

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except OSError, error:

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except subprocess.OSError, error:

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logger.error(u"Failed to start subprocess: %s",

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error)

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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:

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return

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logger.debug(u"Stopping checker for %(name)s", vars(self))

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logger.debug("Stopping checker for %(name)s", vars(self))

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362

try:

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os.kill(self.checker.pid, signal.SIGTERM)

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#os.sleep(0.5)

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def fingerprint(openpgp):

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"Convert an OpenPGP bytestring to a hexdigit fingerprint string"

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# New empty GnuTLS certificate

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crt = gnutls.library.types.gnutls_openpgp_crt_t()

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gnutls.library.functions.gnutls_openpgp_crt_init\

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(ctypes.byref(crt))

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# New GnuTLS "datum" with the OpenPGP public key

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datum = gnutls.library.types.gnutls_datum_t\

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(ctypes.cast(ctypes.c_char_p(openpgp),

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ctypes.POINTER(ctypes.c_ubyte)),

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ctypes.c_uint(len(openpgp)))

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# New empty GnuTLS certificate

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crt = gnutls.library.types.gnutls_openpgp_crt_t()

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gnutls.library.functions.gnutls_openpgp_crt_init\

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(ctypes.byref(crt))

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# Import the OpenPGP public key into the certificate

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gnutls.library.functions.gnutls_openpgp_crt_import\

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(crt, ctypes.byref(datum),

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gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)

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# Verify the self signature in the key

414

crtverify = ctypes.c_uint();

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gnutls.library.functions.gnutls_openpgp_crt_verify_self\

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(crt, ctypes.c_uint(0), ctypes.byref(crtverify))

417

if crtverify.value != 0:

418

tmp = open("/tmp/tmp.gpg", "w")

419

tmp.write(openpgp)

420

tmp.close()

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gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)

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raise gnutls.errors.CertificateSecurityError("Verify failed")

409

ret = gnutls.library.functions.gnutls_openpgp_crt_import\

410

(crt,

411

ctypes.byref(datum),

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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."""

442

432

443

433

def handle(self):

444

logger.info(u"TCP connection from: %s",

434

logger.debug(u"TCP connection from: %s",

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435

unicode(self.client_address))

446

session = gnutls.connection.ClientSession\

447

(self.request, gnutls.connection.X509Credentials())

448

436

449

437

line = self.request.makefile().readline()

450

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logger.debug(u"Protocol version: %r", line)

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try:

455

443

logger.error(u"Unknown protocol version: %s", error)

456

444

return

457

445

446

session = gnutls.connection.ClientSession\

447

(self.request, gnutls.connection.X509Credentials())

458

448

# Note: gnutls.connection.X509Credentials is really a generic

459

449

# GnuTLS certificate credentials object so long as no X.509

460

450

# keys are added to it. Therefore, we can use it here despite

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463

try:

474

464

session.handshake()

475

465

except gnutls.errors.GNUTLSError, error:

476

logger.warning(u"Handshake failed: %s", error)

466

logger.debug(u"Handshake failed: %s", error)

477

467

# Do not run session.bye() here: the session is not

478

468

# established. Just abandon the request.

479

469

return

480

470

try:

481

471

fpr = fingerprint(peer_certificate(session))

482

472

except (TypeError, gnutls.errors.GNUTLSError), error:

483

logger.warning(u"Bad certificate: %s", error)

473

logger.debug(u"Bad certificate: %s", error)

484

474

session.bye()

485

475

return

486

476

logger.debug(u"Fingerprint: %s", fpr)

490

480

client = c

491

481

break

492

482

if not client:

493

logger.warning(u"Client not found for fingerprint: %s",

494

fpr)

483

logger.debug(u"Client not found for fingerprint: %s", fpr)

495

484

session.bye()

496

485

return

497

486

# Have to check if client.still_valid(), since it is possible

498

487

# that the client timed out while establishing the GnuTLS

499

488

# session.

500

489

if not client.still_valid():

501

logger.warning(u"Client %(name)s is invalid",

502

vars(client))

490

logger.debug(u"Client %(name)s is invalid", vars(client))

503

491

session.bye()

504

492

return

505

493

sent_size = 0

540

528

self.settings["interface"])

541

529

except socket.error, error:

542

530

if error[0] == errno.EPERM:

543

logger.error(u"No permission to"

544

u" bind to interface %s",

545

self.settings["interface"])

531

logger.warning(u"No permission to"

532

u" bind to interface %s",

533

self.settings["interface"])

546

534

else:

547

535

raise error

548

536

# Only bind(2) the socket if we really need to.

551

539

in6addr_any = "::"

552

540

self.server_address = (in6addr_any,

553

541

self.server_address[1])

554

elif not self.server_address[1]:

542

elif self.server_address[1] is None:

555

543

self.server_address = (self.server_address[0],

556

544

0)

557

# if self.settings["interface"]:

558

# self.server_address = (self.server_address[0],

559

# 0, # port

560

# 0, # flowinfo

561

# if_nametoindex

562

# (self.settings

563

# ["interface"]))

564

545

return super(type(self), self).server_bind()

565

546

566

547

577

558

datetime.timedelta(1)

578

559

>>> string_to_delta(u'1w')

579

560

datetime.timedelta(7)

580

>>> string_to_delta('5m 30s')

581

datetime.timedelta(0, 330)

582

561

"""

583

timevalue = datetime.timedelta(0)

584

for s in interval.split():

585

try:

586

suffix=unicode(s[-1])

587

value=int(s[:-1])

588

if suffix == u"d":

589

delta = datetime.timedelta(value)

590

elif suffix == u"s":

591

delta = datetime.timedelta(0, value)

592

elif suffix == u"m":

593

delta = datetime.timedelta(0, 0, 0, 0, value)

594

elif suffix == u"h":

595

delta = datetime.timedelta(0, 0, 0, 0, 0, value)

596

elif suffix == u"w":

597

delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)

598

else:

599

raise ValueError

600

except (ValueError, IndexError):

562

try:

563

suffix=unicode(interval[-1])

564

value=int(interval[:-1])

565

if suffix == u"d":

566

delta = datetime.timedelta(value)

567

elif suffix == u"s":

568

delta = datetime.timedelta(0, value)

569

elif suffix == u"m":

570

delta = datetime.timedelta(0, 0, 0, 0, value)

571

elif suffix == u"h":

572

delta = datetime.timedelta(0, 0, 0, 0, 0, value)

573

elif suffix == u"w":

574

delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)

575

else:

601

576

raise ValueError

602

timevalue += delta

603

return timevalue

577

except (ValueError, IndexError):

578

raise ValueError

579

return delta

604

580

605

581

606

582

def server_state_changed(state):

607

583

"""Derived from the Avahi example code"""

608

584

if state == avahi.SERVER_COLLISION:

609

logger.error(u"Server name collision")

585

logger.warning(u"Server name collision")

610

586

service.remove()

611

587

elif state == avahi.SERVER_RUNNING:

612

588

service.add()

626

602

unicode(error))

627

603

raise AvahiGroupError("State changed: %s", str(error))

628

604

629

def if_nametoindex(interface):

605

def if_nametoindex(interface, _func=[None]):

630

606

"""Call the C function if_nametoindex(), or equivalent"""

631

global if_nametoindex

607

if _func[0] is not None:

608

return _func[0](interface)

632

609

try:

633

610

if "ctypes.util" not in sys.modules:

634

611

import ctypes.util

635

if_nametoindex = ctypes.cdll.LoadLibrary\

636

(ctypes.util.find_library("c")).if_nametoindex

612

while True:

613

try:

614

libc = ctypes.cdll.LoadLibrary\

615

(ctypes.util.find_library("c"))

616

_func[0] = libc.if_nametoindex

617

return _func[0](interface)

618

except IOError, e:

619

if e != errno.EINTR:

620

raise

637

621

except (OSError, AttributeError):

638

622

if "struct" not in sys.modules:

639

623

import struct

640

624

if "fcntl" not in sys.modules:

641

625

import fcntl

642

def if_nametoindex(interface):

626

def the_hard_way(interface):

643

627

"Get an interface index the hard way, i.e. using fcntl()"

644

628

SIOCGIFINDEX = 0x8933 # From /usr/include/linux/sockios.h

645

629

s = socket.socket()

648

632

s.close()

649

633

interface_index = struct.unpack("I", ifreq[16:20])[0]

650

634

return interface_index

651

return if_nametoindex(interface)

652

653

654

def daemon(nochdir = False, noclose = False):

635

_func[0] = the_hard_way

636

return _func[0](interface)

637

638

639

def daemon(nochdir, noclose):

655

640

"""See daemon(3). Standard BSD Unix function.

656

641

This should really exist as os.daemon, but it doesn't (yet)."""

657

642

if os.fork():

659

644

os.setsid()

660

645

if not nochdir:

661

646

os.chdir("/")

662

if os.fork():

663

sys.exit()

664

647

if not noclose:

665

648

# Close all standard open file descriptors

666

649

null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)

678

661

global main_loop_started

679

662

main_loop_started = False

680

663

681

parser = OptionParser(version = "%%prog %s" % version)

664

parser = OptionParser()

682

665

parser.add_option("-i", "--interface", type="string",

683

666

metavar="IF", help="Bind to interface IF")

684

667

parser.add_option("-a", "--address", type="string",

687

670

help="Port number to receive requests on")

688

671

parser.add_option("--check", action="store_true", default=False,

689

672

help="Run self-test")

690

parser.add_option("--debug", action="store_true",

673

parser.add_option("--debug", action="store_true", default=False,

691

674

help="Debug mode; run in foreground and log to"

692

675

" terminal")

693

676

parser.add_option("--priority", type="string", help="GnuTLS"

718

701

# Parse config file for server-global settings

719

702

server_config = ConfigParser.SafeConfigParser(server_defaults)

720

703

del server_defaults

721

server_config.read(os.path.join(options.configdir, "mandos.conf"))

704

server_config.read(os.path.join(options.configdir, "server.conf"))

705

server_section = "server"

722

706

# Convert the SafeConfigParser object to a dict

723

server_settings = server_config.defaults()

707

server_settings = dict(server_config.items(server_section))

724

708

# Use getboolean on the boolean config option

725

709

server_settings["debug"] = server_config.getboolean\

726

("DEFAULT", "debug")

710

(server_section, "debug")

727

711

del server_config

728

712

729

713

# Override the settings from the config file with command line

736

720

del options

737

721

# Now we have our good server settings in "server_settings"

738

722

739

debug = server_settings["debug"]

740

741

if not debug:

742

syslogger.setLevel(logging.WARNING)

743

console.setLevel(logging.WARNING)

744

745

if server_settings["servicename"] != "Mandos":

746

syslogger.setFormatter(logging.Formatter\

747

('Mandos (%s): %%(levelname)s:'

748

' %%(message)s'

749

% server_settings["servicename"]))

750

751

723

# Parse config file with clients

752

724

client_defaults = { "timeout": "1h",

753

725

"interval": "5m",

754

"checker": "fping -q -- %(host)s",

755

"host": "",

726

"checker": "fping -q -- %%(fqdn)s",

756

727

}

757

728

client_config = ConfigParser.SafeConfigParser(client_defaults)

758

729

client_config.read(os.path.join(server_settings["configdir"],

776

747

avahi.DBUS_INTERFACE_SERVER )

777

748

# End of Avahi example code

778

749

750

debug = server_settings["debug"]

751

752

if debug:

753

console = logging.StreamHandler()

754

# console.setLevel(logging.DEBUG)

755

console.setFormatter(logging.Formatter\

756

('%(levelname)s: %(message)s'))

757

logger.addHandler(console)

758

del console

759

779

760

clients = Set()

780

761

def remove_from_clients(client):

781

762

clients.remove(client)

782

763

if not clients:

783

logger.critical(u"No clients left, exiting")

764

logger.debug(u"No clients left, exiting")

784

765

sys.exit()

785

766

786

clients.update(Set(Client(name = section,

767

clients.update(Set(Client(name=section,

787

768

stop_hook = remove_from_clients,

788

config

789

= dict(client_config.items(section)))

769

**(dict(client_config\

770

.items(section))))

790

771

for section in client_config.sections()))

791

if not clients:

792

logger.critical(u"No clients defined")

793

sys.exit(1)

794

795

if debug:

796

# Redirect stdin so all checkers get /dev/null

797

null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)

798

os.dup2(null, sys.stdin.fileno())

799

if null > 2:

800

os.close(null)

801

else:

802

# No console logging

803

logger.removeHandler(console)

804

# Close all input and output, do double fork, etc.

805

daemon()

806

807

pidfilename = "/var/run/mandos/mandos.pid"

808

pid = os.getpid()

809

try:

810

pidfile = open(pidfilename, "w")

811

pidfile.write(str(pid) + "\n")

812

pidfile.close()

813

del pidfile

814

except IOError, err:

815

logger.error(u"Could not write %s file with PID %d",

816

pidfilename, os.getpid())

772

773

if not debug:

774

daemon(False, False)

817

775

818

776

def cleanup():

819

777

"Cleanup function; run on exit"

846

804

clients=clients)

847

805

# Find out what port we got

848

806

service.port = tcp_server.socket.getsockname()[1]

849

logger.info(u"Now listening on address %r, port %d, flowinfo %d,"

850

u" scope_id %d" % tcp_server.socket.getsockname())

807

logger.debug(u"Now listening on address %r, port %d, flowinfo %d,"

808

u" scope_id %d" % tcp_server.socket.getsockname())

851

809

852

810

#service.interface = tcp_server.socket.getsockname()[3]

853

811

866

824

tcp_server.handle_request\

867

825

(*args[2:], **kwargs) or True)

868

826

869

logger.debug(u"Starting main loop")

827

logger.debug("Starting main loop")

870

828

main_loop_started = True

871

829

main_loop.run()

872

830

except AvahiError, error: