auth.py

# -*- coding: utf-8 -*-

""" OneLogin_Saml2_Auth class

Copyright (c) 2014, OneLogin, Inc.
All rights reserved.

Main class of OneLogin's Python Toolkit.

Initializes the SP SAML instance

"""

import logging
from base64 import b64encode
from urllib import quote_plus
from os.path import dirname, join
from jinja2 import Template

import dm.xmlsec.binding as xmlsec

from onelogin.saml2.settings import OneLogin_Saml2_Settings
from onelogin.saml2.response import OneLogin_Saml2_Response
from onelogin.saml2.errors import OneLogin_Saml2_Error
from onelogin.saml2.logout_response import OneLogin_Saml2_Logout_Response
from onelogin.saml2.constants import OneLogin_Saml2_Constants
from onelogin.saml2.utils import OneLogin_Saml2_Utils
from onelogin.saml2.logout_request import OneLogin_Saml2_Logout_Request
from onelogin.saml2.authn_request import OneLogin_Saml2_Authn_Request

log = logging.getLogger(__name__)


class OneLogin_Saml2_Auth(object):
    """

    This class implements the SP SAML instance.

    Defines the methods that you can invoke in your application in
    order to add SAML support (initiates sso, initiates slo, processes a
    SAML Response, a Logout Request or a Logout Response).
    """

    def __init__(self, request_data, old_settings=None, custom_base_path=None):
        """
        Initializes the SP SAML instance.

        :param request_data: Request Data
        :type request_data: dict

        :param settings: Optional. SAML Toolkit Settings
        :type settings: dict|object

        :param custom_base_path: Optional. Path where are stored the settings file and the cert folder
        :type custom_base_path: string
        """
        self.__request_data = request_data
        self.__settings = OneLogin_Saml2_Settings(old_settings, custom_base_path)
        self.__attributes = []
        self.__nameid = None
        self.__session_index = None
        self.__authenticated = False
        self.__errors = []
        self.__error_reason = None

    def get_settings(self):
        """
        Returns the settings info
        :return: Setting info
        :rtype: OneLogin_Saml2_Setting object
        """
        return self.__settings

    def set_strict(self, value):
        """
        Set the strict mode active/disable

        :param value:
        :type value: bool
        """
        assert isinstance(value, bool)
        self.__settings.set_strict(value)

    def process_response(self, request_id=None):
        """
        Process the SAML Response sent by the IdP.

        :param request_id: Is an optional argumen. Is the ID of the AuthNRequest sent by this SP to the IdP.
        :type request_id: string

        :raises: OneLogin_Saml2_Error.SAML_RESPONSE_NOT_FOUND, when a POST with a SAMLResponse is not found
        """
        self.__errors = []

        if 'post_data' in self.__request_data and 'SAMLResponse' in self.__request_data['post_data']:
            # AuthnResponse -- HTTP_POST Binding
            response = OneLogin_Saml2_Response(self.__settings, self.__request_data['post_data']['SAMLResponse'])

            if response.is_valid(self.__request_data, request_id):
                self.__attributes = response.get_attributes()
                self.__nameid = response.get_nameid()
                self.__session_index = response.get_session_index()
                self.__authenticated = True

            else:
                self.__errors.append('invalid_response')
                self.__error_reason = response.get_error()

        else:
            self.__errors.append('invalid_binding')
            raise OneLogin_Saml2_Error(
                'SAML Response not found, Only supported HTTP_POST Binding',
                OneLogin_Saml2_Error.SAML_RESPONSE_NOT_FOUND
            )

    def process_slo(self, keep_local_session=False, request_id=None, delete_session_cb=None):
        """
        Process the SAML Logout Response / Logout Request sent by the IdP.

        :param keep_local_session: When false will destroy the local session, otherwise will destroy it
        :type keep_local_session: bool

        :param request_id: The ID of the LogoutRequest sent by this SP to the IdP
        :type request_id: string

        :returns: Redirection url
        """
        self.__errors = []

        if 'get_data' in self.__request_data and 'SAMLResponse' in self.__request_data['get_data']:
            logout_response = OneLogin_Saml2_Logout_Response(self.__settings, self.__request_data['get_data']['SAMLResponse'])
            if not logout_response.is_valid(self.__request_data, request_id):
                self.__errors.append('invalid_logout_response')
                self.__error_reason = logout_response.get_error()
            elif logout_response.get_status() != OneLogin_Saml2_Constants.STATUS_SUCCESS:
                self.__errors.append('logout_not_success')
            elif not keep_local_session:
                OneLogin_Saml2_Utils.delete_local_session(delete_session_cb)

        elif 'get_data' in self.__request_data and 'SAMLRequest' in self.__request_data['get_data']:
            logout_request = OneLogin_Saml2_Logout_Request(self.__settings, self.__request_data['get_data']['SAMLRequest'])
            if not logout_request.is_valid(self.__request_data):
                self.__errors.append('invalid_logout_request')
                self.__error_reason = logout_request.get_error()
            else:
                if not keep_local_session:
                    OneLogin_Saml2_Utils.delete_local_session(delete_session_cb)

                in_response_to = logout_request.id
                response_builder = OneLogin_Saml2_Logout_Response(self.__settings)
                response_builder.build(in_response_to)
                logout_response = response_builder.get_response()

                parameters = {'SAMLResponse': logout_response}
                if 'RelayState' in self.__request_data['get_data']:
                    parameters['RelayState'] = self.__request_data['get_data']['RelayState']

                security = self.__settings.get_security_data()
                if 'logoutResponseSigned' in security and security['logoutResponseSigned']:
                    parameters['SigAlg'] = security['signatureAlgorithm']
                    parameters['Signature'] = self.build_response_signature(logout_response, parameters.get('RelayState', None), security['signatureAlgorithm'])

                return self.redirect_to(self.get_slo_url(), parameters)
        else:
            self.__errors.append('invalid_binding')
            raise OneLogin_Saml2_Error(
                'SAML LogoutRequest/LogoutResponse not found. Only supported HTTP_REDIRECT Binding',
                OneLogin_Saml2_Error.SAML_LOGOUTMESSAGE_NOT_FOUND
            )

    def redirect_to(self, url=None, parameters={}):
        """
        Redirects the user to the url past by parameter or to the url that we defined in our SSO Request.

        :param url: The target URL to redirect the user
        :type url: string
        :param parameters: Extra parameters to be passed as part of the url
        :type parameters: dict

        :returns: Redirection url
        """
        if url is None and 'RelayState' in self.__request_data['get_data']:
            url = self.__request_data['get_data']['RelayState']
        return OneLogin_Saml2_Utils.redirect(url, parameters, request_data=self.__request_data)

    def is_authenticated(self):
        """
        Checks if the user is authenticated or not.

        :returns: True if is authenticated, False if not
        :rtype: bool
        """
        return self.__authenticated

    def get_attributes(self):
        """
        Returns the set of SAML attributes.

        :returns: SAML attributes
        :rtype: dict
        """
        return self.__attributes

    def get_nameid(self):
        """
        Returns the nameID.

        :returns: NameID
        :rtype: string
        """
        return self.__nameid

    def get_session_index(self):
        """
        Returns the SessionIndex from the AuthnStatement.
        :returns: The SessionIndex of the assertion
        :rtype: string
        """
        return self.__session_index

    def get_errors(self):
        """
        Returns a list with code errors if something went wrong

        :returns: List of errors
        :rtype: list
        """
        return self.__errors

    def get_last_error_reason(self):
        """
        Returns the reason for the last error

        :returns: Reason of the last error
        :rtype: None | string
        """
        return self.__error_reason

    def get_attribute(self, name):
        """
        Returns the requested SAML attribute.

        :param name: Name of the attribute
        :type name: string

        :returns: Attribute value if exists or []
        :rtype: string
        """
        assert isinstance(name, basestring)
        value = None
        if self.__attributes and name in self.__attributes.keys():
            value = self.__attributes[name]
        return value

    def login(self, return_to=None, force_authn=False, is_passive=False):
        """
        Initiates the SSO process.

        :param return_to: Optional argument. The target URL the user should be redirected to after login.
        :type return_to: string

        :param force_authn: Optional argument. When true the AuthNReuqest will set the ForceAuthn='true'.
        :type force_authn: string

        :param is_passive: Optional argument. When true the AuthNReuqest will set the Ispassive='true'.
        :type is_passive: string

        :returns: Redirection url
        """
        authn_request = OneLogin_Saml2_Authn_Request(self.__settings, force_authn, is_passive)

        saml_request = authn_request.get_request()
        parameters = {'SAMLRequest': saml_request}

        if return_to is not None:
            parameters['RelayState'] = return_to
        else:
            parameters['RelayState'] = OneLogin_Saml2_Utils.get_self_url_no_query(self.__request_data)

        security = self.__settings.get_security_data()
        if security.get('authnRequestsSigned', False):
            parameters['SigAlg'] = security['signatureAlgorithm']
            parameters['Signature'] = self.build_request_signature(saml_request, parameters['RelayState'], security['signatureAlgorithm'])

        # HTTP-POST binding requires generation of a form
        if self.get_settings().get_idp_data()['singleSignOnService'].get('binding', None) == 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST':
            log.debug("Generating AuthnRequest HTTP-POST binding form")

            # Return HTML form
            template_file = open(join(dirname(__file__), 'templates/authn_request.html'))
            template_text = template_file.read()
            template = Template(template_text)

            context = {
                'sso_url': self.get_sso_url(),
                'saml_request': saml_request,
                'relay_state': parameters['RelayState']
            }

            html = template.render(context)
            log.debug("Generated HTML: %s" % html)

            return html

        return self.redirect_to(self.get_sso_url(), parameters)

    def logout(self, return_to=None, name_id=None, session_index=None):
        """
        Initiates the SLO process.

        :param return_to: Optional argument. The target URL the user should be redirected to after logout.
        :type return_to: string

        :param name_id: The NameID that will be set in the LogoutRequest.
        :type name_id: string

        :param session_index: SessionIndex that identifies the session of the user.
        :type session_index: string

        :returns: Redirection url
        """
        slo_url = self.get_slo_url()
        if slo_url is None:
            raise OneLogin_Saml2_Error(
                'The IdP does not support Single Log Out',
                OneLogin_Saml2_Error.SAML_SINGLE_LOGOUT_NOT_SUPPORTED
            )

        if name_id is None and self.__nameid is not None:
            name_id = self.__nameid

        logout_request = OneLogin_Saml2_Logout_Request(self.__settings, name_id=name_id, session_index=session_index)

        saml_request = logout_request.get_request()

        parameters = {'SAMLRequest': logout_request.get_request()}
        if return_to is not None:
            parameters['RelayState'] = return_to
        else:
            parameters['RelayState'] = OneLogin_Saml2_Utils.get_self_url_no_query(self.__request_data)

        security = self.__settings.get_security_data()
        if security.get('logoutRequestSigned', False):
            parameters['SigAlg'] = security['signatureAlgorithm']
            parameters['Signature'] = self.build_request_signature(saml_request, parameters['RelayState'], security['signatureAlgorithm'])
        return self.redirect_to(slo_url, parameters)

    def get_sso_url(self):
        """
        Gets the SSO url.

        :returns: An URL, the SSO endpoint of the IdP
        :rtype: string
        """
        idp_data = self.__settings.get_idp_data()
        return idp_data['singleSignOnService']['url']

    def get_slo_url(self):
        """
        Gets the SLO url.

        :returns: An URL, the SLO endpoint of the IdP
        :rtype: string
        """
        url = None
        idp_data = self.__settings.get_idp_data()
        if 'singleLogoutService' in idp_data.keys() and 'url' in idp_data['singleLogoutService']:
            url = idp_data['singleLogoutService']['url']
        return url

    def build_request_signature(self, saml_request, relay_state, sign_algorithm=OneLogin_Saml2_Constants.RSA_SHA1):
        """
        Builds the Signature of the SAML Request.

        :param saml_request: The SAML Request
        :type saml_request: string

        :param relay_state: The target URL the user should be redirected to
        :type relay_state: string

        :param sign_algorithm: Signature algorithm method
        :type sign_algorithm: string
        """
        return self.__build_signature(saml_request, relay_state, 'SAMLRequest', sign_algorithm)

    def build_response_signature(self, saml_response, relay_state, sign_algorithm=OneLogin_Saml2_Constants.RSA_SHA1):
        """
        Builds the Signature of the SAML Response.
        :param saml_request: The SAML Response
        :type saml_request: string

        :param relay_state: The target URL the user should be redirected to
        :type relay_state: string

        :param sign_algorithm: Signature algorithm method
        :type sign_algorithm: string
        """
        return self.__build_signature(saml_response, relay_state, 'SAMLResponse', sign_algorithm)

    def __build_signature(self, saml_data, relay_state, saml_type, sign_algorithm=OneLogin_Saml2_Constants.RSA_SHA1):
        """
        Builds the Signature
        :param saml_data: The SAML Data
        :type saml_data: string

        :param relay_state: The target URL the user should be redirected to
        :type relay_state: string

        :param saml_type: The target URL the user should be redirected to
        :type saml_type: string  SAMLRequest | SAMLResponse

        :param sign_algorithm: Signature algorithm method
        :type sign_algorithm: string
        """
        assert saml_type in ['SAMLRequest', 'SAMLResponse']

        # Load the key into the xmlsec context
        key = self.__settings.get_sp_key()

        if not key:
            raise OneLogin_Saml2_Error(
                "Trying to sign the %s but can't load the SP private key" % saml_type,
                OneLogin_Saml2_Error.SP_CERTS_NOT_FOUND
            )

        xmlsec.initialize()

        dsig_ctx = xmlsec.DSigCtx()
        dsig_ctx.signKey = xmlsec.Key.loadMemory(key, xmlsec.KeyDataFormatPem, None)

        saml_data_str = '%s=%s' % (saml_type, quote_plus(saml_data))
        relay_state_str = 'RelayState=%s' % quote_plus(relay_state)
        alg_str = 'SigAlg=%s' % quote_plus(sign_algorithm)

        sign_data = [saml_data_str, relay_state_str, alg_str]
        msg = '&'.join(sign_data)

        # Sign the metadata with our private key.
        sign_algorithm_transform_map = {
            OneLogin_Saml2_Constants.DSA_SHA1: xmlsec.TransformDsaSha1,
            OneLogin_Saml2_Constants.RSA_SHA1: xmlsec.TransformRsaSha1,
            OneLogin_Saml2_Constants.RSA_SHA256: xmlsec.TransformRsaSha256,
            OneLogin_Saml2_Constants.RSA_SHA384: xmlsec.TransformRsaSha384,
            OneLogin_Saml2_Constants.RSA_SHA512: xmlsec.TransformRsaSha512
        }
        sign_algorithm_transform = sign_algorithm_transform_map.get(sign_algorithm, xmlsec.TransformRsaSha1)

        signature = dsig_ctx.signBinary(str(msg), sign_algorithm_transform)
        return b64encode(signature)