473 lines
17 KiB
Python
473 lines
17 KiB
Python
#!/usr/bin/python
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# -*- coding: utf-8 -*-
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#
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# Copyright (C) 2010 Umeå University
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import base64
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import sys
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from saml2 import samlp
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from saml2 import saml
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from saml2 import extension_element_to_element
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from saml2 import time_util
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from saml2.sigver import security_context
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from saml2.attribute_converter import to_local
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from saml2.time_util import str_to_time
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from saml2.validate import validate_on_or_after
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from saml2.validate import validate_before
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from saml2.validate import valid_instance
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from saml2.validate import valid_address
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from saml2.validate import NotValid
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# ---------------------------------------------------------------------------
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class IncorrectlySigned(Exception):
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pass
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# ---------------------------------------------------------------------------
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def _dummy(_arg):
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return None
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def for_me(condition, myself ):
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# Am I among the intended audiences
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for restriction in condition.audience_restriction:
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for audience in restriction.audience:
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if audience.text.strip() == myself:
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return True
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else:
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#print "Not for me: %s != %s" % (audience.text.strip(), myself)
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pass
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return False
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def authn_response(conf, entity_id, return_addr, outstanding_queries=None,
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log=None, timeslack=0, debug=0):
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sec = security_context(conf)
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if not timeslack:
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try:
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timeslack = int(conf["timeslack"])
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except KeyError:
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pass
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return AuthnResponse(sec, conf.attribute_converters, entity_id,
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return_addr, outstanding_queries, log, timeslack,
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debug)
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class StatusResponse(object):
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def __init__(self, sec_context, return_addr=None, log=None, timeslack=0,
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debug=0, request_id=0):
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self.sec = sec_context
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self.return_addr = return_addr
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self.timeslack = timeslack
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self.request_id = request_id
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self.log = log
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self.debug = debug
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if self.debug and not self.log:
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self.debug = 0
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self.xmlstr = ""
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self.name_id = ""
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self.response = None
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self.not_on_or_after = 0
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self.in_response_to = None
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self.signature_check = self.sec.correctly_signed_response
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def _clear(self):
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self.xmlstr = ""
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self.name_id = ""
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self.response = None
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self.not_on_or_after = 0
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def _postamble(self):
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if not self.response:
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if self.log:
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self.log.error("Response was not correctly signed")
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if self.xmlstr:
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self.log.info(self.xmlstr)
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raise IncorrectlySigned()
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if self.debug:
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self.log.info("response: %s" % (self.response,))
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try:
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valid_instance(self.response)
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except NotValid, exc:
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if self.log:
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self.log.error("Not valid response: %s" % exc.args[0])
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else:
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print >> sys.stderr, "Not valid response: %s" % exc.args[0]
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self.clear()
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return self
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self.in_response_to = self.response.in_response_to
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return self
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def load_instance(self, instance):
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self.response = self.sec.check_signature(instance)
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return self._postamble()
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def _loads(self, xmldata, decode=True):
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if decode:
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decoded_xml = base64.b64decode(xmldata)
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else:
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decoded_xml = xmldata
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# own copy
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self.xmlstr = decoded_xml[:]
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if self.debug:
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self.log.info("xmlstr: %s" % (self.xmlstr,))
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try:
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self.response = self.signature_check(decoded_xml)
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except Exception, excp:
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self.log and self.log.info("EXCEPTION: %s", excp)
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return self._postamble()
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def status_ok(self):
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if self.response.status:
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status = self.response.status
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if self.log:
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self.log.info("status: %s" % (status,))
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if status.status_code.value != samlp.STATUS_SUCCESS:
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if self.log:
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self.log.info("Not successfull operation: %s" % status)
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raise Exception(
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"Not successfull according to: %s" % \
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status.status_code.value)
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return True
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def issue_instant_ok(self):
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""" Check that the response was issued at a reasonable time """
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upper = time_util.shift_time(time_util.time_in_a_while(days=1),
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self.timeslack).timetuple()
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lower = time_util.shift_time(time_util.time_a_while_ago(days=1),
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-self.timeslack).timetuple()
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# print "issue_instant: %s" % self.response.issue_instant
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# print "%s < x < %s" % (lower, upper)
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issued_at = str_to_time(self.response.issue_instant)
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return issued_at > lower and issued_at < upper
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def _verify(self):
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if self.request_id and self.in_response_to and \
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self.in_response_to != self.request_id:
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if self.log:
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self.log.error("Not the id I expected: %s != %s" % (
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self.in_response_to,
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self.request_id))
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return None
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assert self.response.version == "2.0"
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if self.response.destination and \
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self.response.destination != self.return_addr:
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if self.log:
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self.log.error("%s != %s" % (self.response.destination,
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self.return_addr))
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return None
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assert self.issue_instant_ok()
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assert self.status_ok()
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return self
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def loads(self, xmldata, decode=True):
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return self._loads(xmldata, decode)
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def verify(self):
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try:
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return self._verify()
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except AssertionError:
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return None
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class LogoutResponse(StatusResponse):
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def __init__(self, sec_context, return_addr=None, log=None, timeslack=0,
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debug=0):
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StatusResponse.__init__(self, sec_context, return_addr, log, timeslack,
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debug)
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self.signature_check = self.sec.correctly_signed_logout_response
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class AuthnResponse(StatusResponse):
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""" This is where all the profile complience is checked.
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This one does saml2int complience. """
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def __init__(self, sec_context, attribute_converters, entity_id,
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return_addr=None, outstanding_queries=None, log=None,
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timeslack=0, debug=0):
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StatusResponse.__init__(self, sec_context, return_addr, log,
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timeslack, debug)
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self.entity_id = entity_id
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self.attribute_converters = attribute_converters
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if outstanding_queries:
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self.outstanding_queries = outstanding_queries
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else:
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self.outstanding_queries = {}
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self.context = "AuthnReq"
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self.came_from = ""
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self.ava = None
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self.assertion = None
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def loads(self, xmldata, decode=True):
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self._loads(xmldata, decode)
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if self.in_response_to in self.outstanding_queries:
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self.came_from = self.outstanding_queries[self.in_response_to]
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del self.outstanding_queries[self.in_response_to]
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return self
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def clear(self):
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self._clear()
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self.came_from = ""
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self.ava = None
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self.assertion = None
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def authn_statement_ok(self):
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# the assertion MUST contain one AuthNStatement
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assert len(self.assertion.authn_statement) == 1
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authn_statement = self.assertion.authn_statement[0]
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if authn_statement.session_not_on_or_after:
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try:
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validate_on_or_after(authn_statement.session_not_on_or_after,
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self.timeslack)
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except Exception:
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return False
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return True
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# check authn_statement.session_index
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def condition_ok(self, lax=False):
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# The Identity Provider MUST include a <saml:Conditions> element
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#print "Conditions",assertion.conditions
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assert self.assertion.conditions
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condition = self.assertion.conditions
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if self.debug:
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self.log.info("condition: %s" % condition)
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try:
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self.not_on_or_after = validate_on_or_after(
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condition.not_on_or_after,
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self.timeslack)
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validate_before(condition.not_before, self.timeslack)
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except Exception, excp:
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self.log and self.log.error("Exception on condition: %s" % (excp,))
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if not lax:
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raise
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else:
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self.not_on_or_after = 0
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if not for_me(condition, self.entity_id):
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if not lax:
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print condition
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print self.entity_id
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raise Exception("Not for me!!!")
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return True
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def get_identity(self):
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# The assertion can contain zero or one attributeStatements
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if not self.assertion.attribute_statement:
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self.log.error("Missing Attribute Statement")
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ava = {}
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else:
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assert len(self.assertion.attribute_statement) == 1
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if self.debug:
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self.log.info("Attribute Statement: %s" % (
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self.assertion.attribute_statement[0],))
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for aconv in self.attribute_converters():
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self.log.info(
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"Converts name format: %s" % (aconv.name_format,))
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ava = to_local(self.attribute_converters(),
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self.assertion.attribute_statement[0])
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return ava
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def get_subject(self):
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# The assertion must contain a Subject
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assert self.assertion.subject
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subject = self.assertion.subject
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subjconf = []
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for subject_confirmation in subject.subject_confirmation:
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data = subject_confirmation.subject_confirmation_data
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if not data:
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# I don't know where this belongs so I ignore it
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continue
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if data.address:
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if not valid_address(data.address):
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# ignore this subject_confirmation
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continue
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# These two will raise exception if untrue
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validate_on_or_after(data.not_on_or_after, self.timeslack)
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validate_before(data.not_before, self.timeslack)
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# not_before must be < not_on_or_after
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if not time_util.later_than(data.not_on_or_after, data.not_before):
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continue
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if not self.came_from:
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if data.in_response_to in self.outstanding_queries:
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self.came_from = self.outstanding_queries[
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data.in_response_to]
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del self.outstanding_queries[data.in_response_to]
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else:
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# This is where I don't allow unsolicited reponses
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# Either in_response_to == None or has a value I don't
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# recognize
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if self.debug:
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self.log.info(
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"in response to: '%s'" % data.in_response_to)
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self.log.info("outstanding queries: %s" % \
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self.outstanding_queries.keys())
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raise Exception(
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"Combination of session id and requestURI I don't recall")
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subjconf.append(subject_confirmation)
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if subjconf == []:
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raise Exception("No valid subject confirmation")
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subject.subject_confirmation = subjconf
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# The subject must contain a name_id
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assert subject.name_id
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self.name_id = subject.name_id.text.strip()
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return self.name_id
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def _assertion(self, assertion):
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self.assertion = assertion
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if self.debug:
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self.log.info("assertion context: %s" % (self.context,))
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self.log.info("assertion keys: %s" % (assertion.keyswv()))
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self.log.info("outstanding_queries: %s" % (
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self.outstanding_queries))
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if self.context == "AuthNReq":
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self.authn_statement_ok()
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if not self.condition_ok():
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return None
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if self.debug:
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self.log.info("--- Getting Identity ---")
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self.ava = self.get_identity()
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if self.debug:
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self.log.info("--- AVA: %s" % (self.ava,))
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try:
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self.get_subject()
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if not self.came_from:
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return False
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else:
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return True
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except Exception:
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return False
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def _encrypted_assertion(self, xmlstr):
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decrypt_xml = self.sec.decrypt(xmlstr)
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if self.debug:
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self.log.info("Decryption successfull")
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self.response = samlp.response_from_string(decrypt_xml)
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if self.debug:
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self.log.info("Parsed decrypted assertion successfull")
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enc = self.response.encrypted_assertion[0].extension_elements[0]
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assertion = extension_element_to_element(enc,
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saml.ELEMENT_FROM_STRING,
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namespace=saml.NAMESPACE)
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if self.debug:
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self.log.info("Decrypted Assertion: %s" % assertion)
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return self._assertion(assertion)
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def parse_assertion(self):
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try:
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assert len(self.response.assertion) == 1 or \
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len(self.response.encrypted_assertion) == 1
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except AssertionError:
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raise Exception("No assertion part")
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if self.response.assertion:
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self.debug and self.log.info("***Unencrypted response***")
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return self._assertion(self.response.assertion[0])
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else:
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self.debug and self.log.info("***Encrypted response***")
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return self._encrypted_assertion(
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self.response.encrypted_assertion[0])
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return True
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def verify(self):
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""" Verify that the assertion is syntactically correct and
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the signature is correct if present."""
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try:
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self._verify()
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except AssertionError:
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return None
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if self.parse_assertion():
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return self
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else:
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return None
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def issuer(self):
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""" Return the issuer of the reponse """
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return self.response.issuer.text
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def session_id(self):
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""" Returns the SessionID of the response """
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return self.response.in_response_to
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def id(self):
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""" Return the ID of the response """
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return self.response.id
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def authn_info(self):
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res = []
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for astat in self.assertion.authn_statement:
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context = astat.authn_context
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if context:
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aclass = context.authn_context_class_ref.text
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try:
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authn_auth = [
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a.text for a in context.authenticating_authority]
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except AttributeError:
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authn_auth = []
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res.append((aclass, authn_auth))
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return res
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def session_info(self):
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""" Returns a predefined set of information gleened from the
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response.
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:returns: Dictionary with information
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"""
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return { "ava": self.ava, "name_id": self.name_id,
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"came_from": self.came_from, "issuer": self.issuer(),
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"not_on_or_after": self.not_on_or_after,
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"authn_info": self.authn_info() }
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def __str__(self):
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return "%s" % self.xmlstr
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