/mandos/release : revision 30

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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:

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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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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

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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

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,

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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."""

439

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def handle(self):

441

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

434

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

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unicode(self.client_address))

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436

session = gnutls.connection.ClientSession\

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

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

447

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

448

try:

449

if int(line.strip().split()[0]) > 1:

450

raise RuntimeError

451

except (ValueError, IndexError, RuntimeError), error:

452

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

453

return

454

455

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

456

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

457

440

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

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453

try:

471

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session.handshake()

472

455

except gnutls.errors.GNUTLSError, error:

473

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

456

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

474

457

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

475

458

# established. Just abandon the request.

476

459

return

477

460

try:

478

461

fpr = fingerprint(peer_certificate(session))

479

462

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

480

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

463

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

481

464

session.bye()

482

465

return

483

466

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

487

470

client = c

488

471

break

489

472

if not client:

490

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

491

fpr)

473

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

492

474

session.bye()

493

475

return

494

476

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

495

477

# that the client timed out while establishing the GnuTLS

496

478

# session.

497

479

if not client.still_valid():

498

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

499

vars(client))

480

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

500

481

session.bye()

501

482

return

502

483

sent_size = 0

537

518

self.settings["interface"])

538

519

except socket.error, error:

539

520

if error[0] == errno.EPERM:

540

logger.error(u"No permission to"

541

u" bind to interface %s",

542

self.settings["interface"])

521

logger.warning(u"No permission to"

522

u" bind to interface %s",

523

self.settings["interface"])

543

524

else:

544

525

raise error

545

526

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

548

529

in6addr_any = "::"

549

530

self.server_address = (in6addr_any,

550

531

self.server_address[1])

551

elif not self.server_address[1]:

532

elif self.server_address[1] is None:

552

533

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

553

534

0)

554

# if self.settings["interface"]:

555

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

556

# 0, # port

557

# 0, # flowinfo

558

# if_nametoindex

559

# (self.settings

560

# ["interface"]))

561

535

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

562

536

563

537

574

548

datetime.timedelta(1)

575

549

>>> string_to_delta(u'1w')

576

550

datetime.timedelta(7)

577

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

578

datetime.timedelta(0, 330)

579

551

"""

580

timevalue = datetime.timedelta(0)

581

for s in interval.split():

582

try:

583

suffix=unicode(s[-1])

584

value=int(s[:-1])

585

if suffix == u"d":

586

delta = datetime.timedelta(value)

587

elif suffix == u"s":

588

delta = datetime.timedelta(0, value)

589

elif suffix == u"m":

590

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

591

elif suffix == u"h":

592

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

593

elif suffix == u"w":

594

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

595

else:

596

raise ValueError

597

except (ValueError, IndexError):

552

try:

553

suffix=unicode(interval[-1])

554

value=int(interval[:-1])

555

if suffix == u"d":

556

delta = datetime.timedelta(value)

557

elif suffix == u"s":

558

delta = datetime.timedelta(0, value)

559

elif suffix == u"m":

560

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

561

elif suffix == u"h":

562

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

563

elif suffix == u"w":

564

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

565

else:

598

566

raise ValueError

599

timevalue += delta

600

return timevalue

567

except (ValueError, IndexError):

568

raise ValueError

569

return delta

601

570

602

571

603

572

def server_state_changed(state):

604

573

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

605

574

if state == avahi.SERVER_COLLISION:

606

logger.error(u"Server name collision")

575

logger.warning(u"Server name collision")

607

576

service.remove()

608

577

elif state == avahi.SERVER_RUNNING:

609

578

service.add()

623

592

unicode(error))

624

593

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

625

594

626

def if_nametoindex(interface):

595

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

627

596

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

628

global if_nametoindex

597

if _func[0] is not None:

598

return _func[0](interface)

629

599

try:

630

600

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

631

601

import ctypes.util

632

if_nametoindex = ctypes.cdll.LoadLibrary\

633

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

602

while True:

603

try:

604

libc = ctypes.cdll.LoadLibrary\

605

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

606

_func[0] = libc.if_nametoindex

607

return _func[0](interface)

608

except IOError, e:

609

if e != errno.EINTR:

610

raise

634

611

except (OSError, AttributeError):

635

612

if "struct" not in sys.modules:

636

613

import struct

637

614

if "fcntl" not in sys.modules:

638

615

import fcntl

639

def if_nametoindex(interface):

616

def the_hard_way(interface):

640

617

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

641

618

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

642

619

s = socket.socket()

645

622

s.close()

646

623

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

647

624

return interface_index

648

return if_nametoindex(interface)

649

650

651

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

625

_func[0] = the_hard_way

626

return _func[0](interface)

627

628

629

def daemon(nochdir, noclose):

652

630

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

653

631

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

654

632

if os.fork():

656

634

os.setsid()

657

635

if not nochdir:

658

636

os.chdir("/")

659

if os.fork():

660

sys.exit()

661

637

if not noclose:

662

638

# Close all standard open file descriptors

663

639

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

675

651

global main_loop_started

676

652

main_loop_started = False

677

653

678

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

654

parser = OptionParser()

679

655

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

680

656

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

681

657

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

684

660

help="Port number to receive requests on")

685

661

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

686

662

help="Run self-test")

687

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

663

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

688

664

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

689

665

" terminal")

690

666

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

715

691

# Parse config file for server-global settings

716

692

server_config = ConfigParser.SafeConfigParser(server_defaults)

717

693

del server_defaults

718

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"

719

696

# Convert the SafeConfigParser object to a dict

720

server_settings = server_config.defaults()

697

server_settings = dict(server_config.items(server_section))

721

698

# Use getboolean on the boolean config option

722

699

server_settings["debug"] = server_config.getboolean\

723

("DEFAULT", "debug")

700

(server_section, "debug")

724

701

del server_config

725

702

726

703

# Override the settings from the config file with command line

733

710

del options

734

711

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

735

712

736

debug = server_settings["debug"]

737

738

if not debug:

739

syslogger.setLevel(logging.WARNING)

740

console.setLevel(logging.WARNING)

741

742

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

743

syslogger.setFormatter(logging.Formatter\

744

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

745

' %%(message)s'

746

% server_settings["servicename"]))

747

748

713

# Parse config file with clients

749

714

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

750

715

"interval": "5m",

751

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

752

"host": "",

716

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

753

717

}

754

718

client_config = ConfigParser.SafeConfigParser(client_defaults)

755

719

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

773

737

avahi.DBUS_INTERFACE_SERVER )

774

738

# End of Avahi example code

775

739

740

debug = server_settings["debug"]

741

742

if debug:

743

console = logging.StreamHandler()

744

# console.setLevel(logging.DEBUG)

745

console.setFormatter(logging.Formatter\

746

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

747

logger.addHandler(console)

748

del console

749

776

750

clients = Set()

777

751

def remove_from_clients(client):

778

752

clients.remove(client)

779

753

if not clients:

780

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

754

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

781

755

sys.exit()

782

756

783

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

757

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

784

758

stop_hook = remove_from_clients,

785

config

786

= dict(client_config.items(section)))

759

**(dict(client_config\

760

.items(section))))

787

761

for section in client_config.sections()))

788

if not clients:

789

logger.critical(u"No clients defined")

790

sys.exit(1)

791

792

if debug:

793

# Redirect stdin so all checkers get /dev/null

794

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

795

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

796

if null > 2:

797

os.close(null)

798

else:

799

# No console logging

800

logger.removeHandler(console)

801

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

802

daemon()

803

804

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

805

pid = os.getpid()

806

try:

807

pidfile = open(pidfilename, "w")

808

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

809

pidfile.close()

810

del pidfile

811

except IOError, err:

812

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

813

pidfilename, os.getpid())

762

763

if not debug:

764

daemon(False, False)

814

765

815

766

def cleanup():

816

767

"Cleanup function; run on exit"

843

794

clients=clients)

844

795

# Find out what port we got

845

796

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

846

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

847

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

797

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

798

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

848

799

849

800

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

850

801

863

814

tcp_server.handle_request\

864

815

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

865

816

866

logger.debug(u"Starting main loop")

817

logger.debug("Starting main loop")

867

818

main_loop_started = True

868

819

main_loop.run()

869

820

except AvahiError, error: