#!/usr/bin/env python # -*- coding: utf-8 -*- # # Copyright (C) 2009-2011 Umeå University # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Contains classes and functions that a SAML2.0 Identity provider (IdP) or attribute authority (AA) may use to conclude its tasks. """ import logging import shelve import sys import memcache from hashlib import sha1 from saml2.samlp import NameIDMappingResponse from saml2.entity import Entity from saml2 import saml from saml2 import class_name from saml2 import BINDING_HTTP_REDIRECT from saml2.request import AuthnRequest from saml2.request import AssertionIDRequest from saml2.request import AttributeQuery from saml2.request import NameIDMappingRequest from saml2.request import AuthzDecisionQuery from saml2.request import AuthnQuery from saml2.s_utils import MissingValue, Unknown from saml2.s_utils import BadRequest from saml2.s_utils import error_status_factory from saml2.sigver import pre_signature_part, signed_instance_factory from saml2.assertion import Assertion from saml2.assertion import Policy from saml2.assertion import restriction_from_attribute_spec from saml2.assertion import filter_attribute_value_assertions from saml2.ident import IdentDB logger = logging.getLogger(__name__) def context_match(cfilter, cntx): # TODO return True class Server(Entity): """ A class that does things that IdPs or AAs do """ def __init__(self, config_file="", config=None, _cache="", stype="idp"): Entity.__init__(self, stype, config, config_file) self.init_config(stype) self._cache = _cache self.ticket = {} self.authn = {} self.assertion = {} def init_config(self, stype="idp"): """ Remaining init of the server configuration :param stype: The type of Server ("idp"/"aa") """ if stype == "aa": return try: # subject information is stored in a database # default database is a shelve database which is OK in some setups dbspec = self.config.getattr("subject_data", "idp") idb = None if isinstance(dbspec, basestring): idb = shelve.open(dbspec, writeback=True) else: # database spec is a a 2-tuple (type, address) print >> sys.stderr, "DBSPEC: %s" % dbspec (typ, addr) = dbspec if typ == "shelve": idb = shelve.open(addr, writeback=True) elif typ == "memcached": idb = memcache.Client(addr) elif typ == "dict": # in-memory dictionary idb = addr if idb is not None: self.ident = IdentDB(idb) else: raise Exception("Couldn't open identity database: %s" % (dbspec,)) except AttributeError: self.ident = None def close_shelve_db(self): """Close the shelve db to prevent file system locking issues""" if self.ident: self.ident.db.close() def wants(self, sp_entity_id, index=None): """ Returns what attributes the SP requires and which are optional if any such demands are registered in the Metadata. :param sp_entity_id: The entity id of the SP :param index: which of the attribute consumer services its all about :return: 2-tuple, list of required and list of optional attributes """ return self.metadata.attribute_requirement(sp_entity_id, index) # ------------------------------------------------------------------------- def parse_authn_request(self, enc_request, binding=BINDING_HTTP_REDIRECT): """Parse a Authentication Request :param enc_request: The request in its transport format :param binding: Which binding that was used to transport the message to this entity. :return: A dictionary with keys: consumer_url - as gotten from the SPs entity_id and the metadata id - the id of the request sp_entity_id - the entity id of the SP request - The verified request """ return self._parse_request(enc_request, AuthnRequest, "single_sign_on_service", binding) def parse_attribute_query(self, xml_string, binding): """ Parse an attribute query :param xml_string: The Attribute Query as an XML string :param binding: Which binding that was used for the request :return: A query instance """ return self._parse_request(xml_string, AttributeQuery, "attribute_service", binding) def parse_authz_decision_query(self, xml_string, binding): """ Parse an attribute query :param xml_string: The Authz decision Query as an XML string :return: Query instance """ return self._parse_request(xml_string, AuthzDecisionQuery, "authz_service", binding) def parse_assertion_id_request(self, xml_string, binding): """ Parse an assertion id query :param xml_string: The AssertionIDRequest as an XML string :return: Query instance """ return self._parse_request(xml_string, AssertionIDRequest, "assertion_id_request_service", binding) def parse_authn_query(self, xml_string, binding): """ Parse an authn query :param xml_string: The AuthnQuery as an XML string :return: Query instance """ return self._parse_request(xml_string, AuthnQuery, "authn_query_service", binding) def parse_name_id_mapping_request(self, xml_string, binding): """ Parse a nameid mapping request :param xml_string: The NameIDMappingRequest as an XML string :return: Query instance """ return self._parse_request(xml_string, NameIDMappingRequest, "manage_name_id_service", binding) # ------------------------------------------------------------------------ def store_assertion(self, assertion, to_sign): self.assertion[assertion.id] = (assertion, to_sign) def get_assertion(self, id): return self.assertion[id] def store_authn_statement(self, authn_statement, name_id): """ :param authn_statement: :param name_id: :return: """ nkey = sha1("%s" % name_id).hexdigest() logger.debug("Store authn_statement under key: %s" % nkey) try: self.authn[nkey].append(authn_statement) except: self.authn[nkey] = [authn_statement] def get_authn_statements(self, name_id, session_index=None, requested_context=None): """ :param name_id: :param session_index: :param requested_context: :return: """ result = [] key = sha1("%s" % name_id).hexdigest() for statement in self.authn[key]: if session_index: if statement.session_index != session_index: continue if requested_context: if not context_match(requested_context, statement.authn_context): continue result.append(statement) return result def remove_authn_statements(self, name_id): nkey = sha1("%s" % name_id).hexdigest() del self.authn[nkey] # ------------------------------------------------------------------------ def _authn_response(self, in_response_to, consumer_url, sp_entity_id, identity=None, name_id=None, status=None, authn=None, authn_decl=None, issuer=None, policy=None, sign_assertion=False, sign_response=False): """ Create a response. A layer of indirection. :param in_response_to: The session identifier of the request :param consumer_url: The URL which should receive the response :param sp_entity_id: The entity identifier of the SP :param identity: A dictionary with attributes and values that are expected to be the bases for the assertion in the response. :param name_id: The identifier of the subject :param status: The status of the response :param authn: A 2-tuple denoting the authn class and the authn authority. :param authn_decl: :param issuer: The issuer of the response :param sign_assertion: Whether the assertion should be signed or not :param sign_response: Whether the response should be signed or not :return: A response instance """ to_sign = [] args = {} if identity: _issuer = self._issuer(issuer) ast = Assertion(identity) if policy is None: policy = Policy() try: ast.apply_policy(sp_entity_id, policy, self.metadata) except MissingValue, exc: return self.create_error_response(in_response_to, consumer_url, exc, sign_response) if authn: # expected to be a 2-tuple class+authority (authn_class, authn_authn) = authn assertion = ast.construct(sp_entity_id, in_response_to, consumer_url, name_id, self.config.attribute_converters, policy, issuer=_issuer, authn_class=authn_class, authn_auth=authn_authn) self.store_authn_statement(assertion.authn_statement, name_id) elif authn_decl: assertion = ast.construct(sp_entity_id, in_response_to, consumer_url, name_id, self.config.attribute_converters, policy, issuer=_issuer, authn_decl=authn_decl) self.store_authn_statement(assertion.authn_statement, name_id) else: assertion = ast.construct(sp_entity_id, in_response_to, consumer_url, name_id, self.config.attribute_converters, policy, issuer=_issuer) if sign_assertion: assertion.signature = pre_signature_part(assertion.id, self.sec.my_cert, 1) # Just the assertion or the response and the assertion ? to_sign = [(class_name(assertion), assertion.id)] # Store which assertion that has been sent to which SP about which # subject. # self.cache.set(assertion.subject.name_id.text, # sp_entity_id, {"ava": identity, "authn": authn}, # assertion.conditions.not_on_or_after) args["assertion"] = assertion self.store_assertion(assertion, to_sign) return self._response(in_response_to, consumer_url, status, issuer, sign_response, to_sign, **args) # ------------------------------------------------------------------------ def create_error_response(self, in_response_to, destination, info, sign=False, issuer=None): """ Create a error response. :param in_response_to: The identifier of the message this is a response to. :param destination: The intended recipient of this message :param info: Either an Exception instance or a 2-tuple consisting of error code and descriptive text :param sign: Whether the response should be signed or not :param issuer: The issuer of the response :return: A response instance """ status = error_status_factory(info) return self._response(in_response_to, destination, status, issuer, sign) # ------------------------------------------------------------------------ #noinspection PyUnusedLocal def create_aa_response(self, in_response_to, consumer_url, sp_entity_id, identity=None, userid="", name_id=None, status=None, issuer=None, sign_assertion=False, sign_response=False, attributes=None): """ Create an attribute assertion response. :param in_response_to: The session identifier of the request :param consumer_url: The URL which should receive the response :param sp_entity_id: The entity identifier of the SP :param identity: A dictionary with attributes and values that are expected to be the bases for the assertion in the response. :param userid: A identifier of the user :param name_id: The identifier of the subject :param status: The status of the response :param issuer: The issuer of the response :param sign_assertion: Whether the assertion should be signed or not :param sign_response: Whether the whole response should be signed :return: A response instance """ if not name_id and userid: try: name_id = self.ident.construct_nameid(userid, self.config.policy, sp_entity_id) logger.warning("Unspecified NameID format") except Exception: pass to_sign = [] args = {} if identity: _issuer = self._issuer(issuer) ast = Assertion(identity) policy = self.config.getattr("policy", "aa") if policy: ast.apply_policy(sp_entity_id, policy) else: policy = Policy() if attributes: restr = restriction_from_attribute_spec(attributes) ast = filter_attribute_value_assertions(ast) assertion = ast.construct(sp_entity_id, in_response_to, consumer_url, name_id, self.config.attribute_converters, policy, issuer=_issuer) if sign_assertion: assertion.signature = pre_signature_part(assertion.id, self.sec.my_cert, 1) # Just the assertion or the response and the assertion ? to_sign = [(class_name(assertion), assertion.id)] args["assertion"] = assertion return self._response(in_response_to, consumer_url, status, issuer, sign_response, to_sign, **args) # ------------------------------------------------------------------------ def create_authn_response(self, identity, in_response_to, destination, sp_entity_id, name_id_policy=None, userid=None, name_id=None, authn=None, authn_decl=None, issuer=None, sign_response=False, sign_assertion=False): """ Constructs an AuthenticationResponse :param identity: Information about an user :param in_response_to: The identifier of the authentication request this response is an answer to. :param destination: Where the response should be sent :param sp_entity_id: The entity identifier of the Service Provider :param name_id_policy: How the NameID should be constructed :param userid: The subject identifier :param authn: Information about the authentication :param authn_decl: :param issuer: Issuer of the response :param sign_assertion: Whether the assertion should be signed or not. :param sign_response: Whether the response should be signed or not. :return: A response instance """ policy = self.config.getattr("policy", "idp") if not name_id: try: nid_formats = [] for _sp in self.metadata[sp_entity_id]["spsso_descriptor"]: if "name_id_format" in _sp: nid_formats.extend([n["text"] for n in _sp["name_id_format"]]) name_id = self.ident.construct_nameid(userid, policy, sp_entity_id, name_id_policy, nid_formats) except IOError, exc: response = self.create_error_response(in_response_to, destination, sp_entity_id, exc, name_id) return ("%s" % response).split("\n") try: return self._authn_response(in_response_to, # in_response_to destination, # consumer_url sp_entity_id, # sp_entity_id identity, # identity as dictionary name_id, authn=authn, # Information about the # authentication authn_decl=authn_decl, issuer=issuer, policy=policy, sign_assertion=sign_assertion, sign_response=sign_response) except MissingValue, exc: return self.create_error_response(in_response_to, destination, sp_entity_id, exc, name_id) def create_assertion_id_request_response(self, assertion_id, sign=False): """ :param assertion_id: :param in_response_to: :param issuer: :param sign_response: :param status: :return: """ try: (assertion, to_sign) = self.get_assertion(assertion_id) except KeyError: raise Unknown if to_sign: if assertion.signature is None: assertion.signature = pre_signature_part(assertion.id, self.sec.my_cert, 1) return signed_instance_factory(assertion, self.sec, to_sign) else: return assertion def create_name_id_mapping_response(self, name_id=None, encrypted_id=None, in_response_to=None, issuer=None, sign_response=False, status=None): """ protocol for mapping a principal's name identifier into a different name identifier for the same principal. Done over soap. :param name_id: :param encrypted_id: :param in_response_to: :param issuer: :param sign_response: :param status: :return: """ # Done over SOAP ms_args = self.message_args() _resp = NameIDMappingResponse(name_id, encrypted_id, in_response_to=in_response_to, **ms_args) if sign_response: return self.sign(_resp) else: logger.info("Message: %s" % _resp) return _resp def create_authn_query_response(self, subject, session_index=None, requested_context=None, in_response_to=None, issuer=None, sign_response=False, status=None): """ A successful will contain one or more assertions containing authentication statements. :return: """ margs = self.message_args() asserts = [] for statement in self.get_authn_statements(subject.name_id, session_index, requested_context): asserts.append(saml.Assertion(authn_statement=statement, subject=subject, **margs)) if asserts: args = {"assertion": asserts} else: args = {} return self._response(in_response_to, "", status, issuer, sign_response, to_sign=[], **args)