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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.thirdparty import suelta
from sleekxmpp.thirdparty.suelta.exceptions import SASLCancelled, SASLError
from sleekxmpp.thirdparty.suelta.exceptions import SASLPrepFailure
from sleekxmpp.stanza import StreamFeatures
from sleekxmpp.xmlstream import RestartStream, register_stanza_plugin
from sleekxmpp.plugins import BasePlugin
from sleekxmpp.xmlstream.matcher import MatchXPath
from sleekxmpp.xmlstream.handler import Callback
from sleekxmpp.features.feature_mechanisms import stanza
log = logging.getLogger(__name__)
class FeatureMechanisms(BasePlugin):
name = 'feature_mechanisms'
description = 'RFC 6120: Stream Feature: SASL'
dependencies = set()
stanza = stanza
def plugin_init(self):
self.use_mech = self.config.get('use_mech', None)
if not self.use_mech and not self.xmpp.boundjid.user:
self.use_mech = 'ANONYMOUS'
def tls_active():
return 'starttls' in self.xmpp.features
def basic_callback(mech, values):
creds = self.xmpp.credentials
for value in values:
if value == 'username':
values['username'] = self.xmpp.boundjid.user
elif value == 'password':
values['password'] = creds['password']
elif value == 'email':
jid = self.xmpp.boundjid.bare
values['email'] = creds.get('email', jid)
elif value in creds:
values[value] = creds[value]
mech.fulfill(values)
sasl_callback = self.config.get('sasl_callback', None)
if sasl_callback is None:
sasl_callback = basic_callback
self.mech = None
self.sasl = suelta.SASL(self.xmpp.boundjid.domain, 'xmpp',
username=self.xmpp.boundjid.user,
sec_query=suelta.sec_query_allow,
request_values=sasl_callback,
tls_active=tls_active,
mech=self.use_mech)
self.mech_list = set()
self.attempted_mechs = set()
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.xmpp.register_stanza(stanza.Challenge)
self.xmpp.register_stanza(stanza.Response)
self.xmpp.register_stanza(stanza.Abort)
self.xmpp.register_handler(
Callback('SASL Success',
MatchXPath(stanza.Success.tag_name()),
self._handle_success,
instream=True))
self.xmpp.register_handler(
Callback('SASL Failure',
MatchXPath(stanza.Failure.tag_name()),
self._handle_fail,
instream=True))
self.xmpp.register_handler(
Callback('SASL Challenge',
MatchXPath(stanza.Challenge.tag_name()),
self._handle_challenge))
self.xmpp.register_feature('mechanisms',
self._handle_sasl_auth,
restart=True,
order=self.config.get('order', 100))
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
if not self.use_mech:
self.mech_list = set(features['mechanisms'])
else:
self.mech_list = set([self.use_mech])
return self._send_auth()
def _send_auth(self):
mech_list = self.mech_list - self.attempted_mechs
self.mech = self.sasl.choose_mechanism(mech_list)
if mech_list and self.mech is not None:
resp = stanza.Auth(self.xmpp)
resp['mechanism'] = self.mech.name
try:
resp['value'] = self.mech.process()
except SASLCancelled:
self.attempted_mechs.add(self.mech.name)
self._send_auth()
except SASLError:
self.attempted_mechs.add(self.mech.name)
self._send_auth()
except SASLPrepFailure:
log.exception("A credential value did not pass SASLprep.")
self.xmpp.disconnect()
else:
resp.send(now=True)
else:
log.error("No appropriate login method.")
self.xmpp.event("no_auth", direct=True)
self.attempted_mechs = set()
self.xmpp.disconnect()
return True
def _handle_challenge(self, stanza):
"""SASL challenge received. Process and send response."""
resp = self.stanza.Response(self.xmpp)
try:
resp['value'] = self.mech.process(stanza['value'])
except SASLCancelled:
self.stanza.Abort(self.xmpp).send()
except SASLError:
self.stanza.Abort(self.xmpp).send()
else:
resp.send(now=True)
def _handle_success(self, stanza):
"""SASL authentication succeeded. Restart the stream."""
self.attempted_mechs = set()
self.xmpp.authenticated = True
self.xmpp.features.add('mechanisms')
raise RestartStream()
def _handle_fail(self, stanza):
"""SASL authentication failed. Disconnect and shutdown."""
self.attempted_mechs.add(self.mech.name)
log.info("Authentication failed: %s", stanza['condition'])
self.xmpp.event("failed_auth", stanza, direct=True)
self._send_auth()
return True
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