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"""
SleekXMPP: The Sleek XMPP Library
Copyright (C) 2011 Nathanael C. Fritz
This file is part of SleekXMPP.
See the file LICENSE for copying permission.
"""
import logging
from sleekxmpp.stanza import StreamFeatures
from sleekxmpp.xmlstream import RestartStream, register_stanza_plugin
from sleekxmpp.xmlstream.matcher import *
from sleekxmpp.xmlstream.handler import *
from sleekxmpp.plugins.base import base_plugin
from sleekxmpp.features.feature_mechanisms import stanza
log = logging.getLogger(__name__)
class feature_mechanisms(base_plugin):
def plugin_init(self):
self.name = 'SASL Mechanisms'
self.rfc = '6120'
self.description = "SASL Stream Feature"
self.stanza = stanza
register_stanza_plugin(StreamFeatures, stanza.Mechanisms)
self.xmpp.register_stanza(stanza.Success)
self.xmpp.register_stanza(stanza.Failure)
self.xmpp.register_stanza(stanza.Auth)
self._mechanism_handlers = {}
self._mechanism_priorities = []
self.xmpp.register_handler(
Callback('SASL Success',
MatchXPath(stanza.Success.tag_name()),
self._handle_success,
instream=True,
once=True))
self.xmpp.register_handler(
Callback('SASL Failure',
MatchXPath(stanza.Failure.tag_name()),
self._handle_fail,
instream=True,
once=True))
self.xmpp.register_feature('mechanisms',
self._handle_sasl_auth,
restart=True,
order=self.config.get('order', 100))
def register(self, name, handler, priority=0):
"""
Register a handler for a SASL authentication mechanism.
Arguments:
name -- The name of the mechanism (all caps)
handler -- The function that will perform the
authentication. The function must
return True if it is able to carry
out the authentication, False if
a required condition is not met.
priority -- An integer value indicating the
preferred ordering for the mechanism.
High values will be attempted first.
"""
self._mechanism_handlers[name] = handler
self._mechanism_priorities.append((priority, name))
self._mechanism_priorities.sort(reverse=True)
def remove(self, name):
"""
Remove support for a given SASL authentication mechanism.
Arguments:
name -- The name of the mechanism to remove (all caps)
"""
if name in self._mechanism_handlers:
del self._mechanism_handlers[name]
p = self._mechanism_priorities
self._mechanism_priorities = [i for i in p if i[1] != name]
def _handle_sasl_auth(self, features):
"""
Handle authenticating using SASL.
Arguments:
features -- The stream features stanza.
"""
if 'mechanisms' in self.xmpp.features:
# SASL authentication has already succeeded, but the
# server has incorrectly offered it again.
return False
for priority, mech in self._mechanism_priorities:
if mech in features['mechanisms']:
log.debug('Attempt to use SASL %s' % mech)
if self._mechanism_handlers[mech]():
break
else:
log.error("No appropriate login method.")
self.xmpp.event("no_auth", direct=True)
self.xmpp.disconnect()
return True
def _handle_success(self, stanza):
"""SASL authentication succeeded. Restart the stream."""
self.xmpp.authenticated = True
self.xmpp.features.add('mechanisms')
raise RestartStream()
def _handle_fail(self, stanza):
"""SASL authentication failed. Disconnect and shutdown."""
log.info("Authentication failed: %s" % stanza['condition'])
self.xmpp.event("failed_auth", stanza, direct=True)
self.xmpp.disconnect()
return True
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