OneLogin's SAML Python Toolkit

Add SAML support to your Python software using this library. Forget those complicated libraries and use the open source library provided and supported by OneLogin Inc.

This version supports Python2. There is a separate version that supports Python3: python3-saml.

Warning

Update python-saml to 2.1.9, this version includes a security patch that contains extra validations that will prevent signature wrapping attacks.

python-saml < v2.1.6 is vulnerable and allows signature wrapping!

Security Guidelines

If you believe you have discovered a security vulnerability in this toolkit, please report it at https://www.onelogin.com/security with a description. We follow responsible disclosure guidelines, and will work with you to quickly find a resolution.

Why add SAML support to my software?

SAML is an XML-based standard for web browser single sign-on and is defined by the OASIS Security Services Technical Committee. The standard has been around since 2002, but lately it is becoming popular due its advantages:

• Usability - One-click access from portals or intranets, deep linking, password elimination and automatically renewing sessions make life easier for the user.
• Security - Based on strong digital signatures for authentication and integrity, SAML is a secure single sign-on protocol that the largest and most security conscious enterprises in the world rely on.
• Speed - SAML is fast. One browser redirect is all it takes to securely sign a user into an application.
• Phishing Prevention - If you don’t have a password for an app, you can’t be tricked into entering it on a fake login page.
• IT Friendly - SAML simplifies life for IT because it centralizes authentication, provides greater visibility and makes directory integration easier.
• Opportunity - B2B cloud vendor should support SAML to facilitate the integration of their product.

General description

OneLogin's SAML Python toolkit lets you turn you Python application into an SP (Service Provider) that can connect to a IdP (Identity Provider).

Supports:

• SSO and SLO (SP-Initiated and IdP-Initiated).
• Assertion and nameId encryption.
• Assertion signatures.
• Message signatures: AuthNRequest, LogoutRequest, LogoutResponses.
• Enable an Assertion Consumer Service endpoint.
• Enable a Single Logout Service endpoint.
• Publish the SP metadata (which can be signed).

Key features:

• saml2int - Implements the SAML 2.0 Web Browser SSO Profile.
• Session-less - Forget those common conflicts between the SP and the final app, the toolkit delegate session in the final app.
• Easy to use - Programmer will be allowed to code high-level and low-level programming, 2 easy to use APIs are available.
• Tested - Thoroughly tested.
• Popular - OneLogin's customers use it. Add easy support to your django/flask/bottle web projects.

Installation

Dependencies

• python 2.7
• dm.xmlsec.binding Cython/lxml based binding for the XML security library (depends on python-dev libxml2-dev libxmlsec1-dev)
• isodate An ISO 8601 date/time/duration parser and formater
• defusedxml XML bomb protection for Python stdlib modules

Review the setup.py file to know the version of the library that python-saml is using

OSX Dependencies

• python 2.7
• libxmlsec1

# using brew
$ brew install libxmlsec1

Code

Option 1. Download from github

The toolkit is hosted on github. You can download it from:

• Lastest release: https://github.com/onelogin/python-saml/releases/latest
• Master repo: https://github.com/onelogin/python-saml/tree/master

Copy the core of the library (src/onelogin/saml2 folder) and merge the setup.py inside the python application. (each application has its structure so take your time to locate the Python SAML toolkit in the best place).

Option 2. Download from pypi

The toolkit is hosted in pypi, you can find the python-saml package at https://pypi.python.org/pypi/python-saml

You can install it executing:

$ pip install python-saml

If you want to know how a project can handle python packages review this guide and review this sampleproject

Security warning

In production, the strict parameter MUST be set as "true". Otherwise your environment is not secure and will be exposed to attacks.

Getting started

Knowing the toolkit

The new OneLogin SAML Toolkit contains different folders (certs, lib, demo-django, demo-flask, demo-bottle and tests) and some files.

Let's start describing them:

src

This folder contains the heart of the toolkit, onelogin/saml2 folder contains the new version of the classes and methods that are described in a later section.

demo-django

This folder contains a Django project that will be used as demo to show how to add SAML support to the Django Framework. 'demo' is the main folder of the django project (with its settings.py, views.py, urls.py), 'templates' is the django templates of the project and 'saml' is a folder that contains the 'certs' folder that could be used to store the x509 public and private key, and the saml toolkit settings (settings.json and advanced_settings.json).

Notice about certs

SAML requires a x.509 cert to sign and encrypt elements like NameID, Message, Assertion, Metadata.

If our environment requires sign or encrypt support, the certs folder may contain the x509 cert and the private key that the SP will use:

• sp.crt The public cert of the SP
• sp.key The private key of the SP

Or also we can provide those data in the setting file at the 'x509cert' and the privateKey' json parameters of the 'sp' element.

Sometimes we could need a signature on the metadata published by the SP, in this case we could use the x.509 cert previously mentioned or use a new x.509 cert: metadata.crt and metadata.key.

If you want to create self-signed certs, you can do it at the https://www.samltool.com/self_signed_certs.php service, or using the command:

openssl req -new -x509 -days 3652 -nodes -out sp.crt -keyout saml.key

demo-bottle

This folder contains a Bottle project that will be used as demo to show how to add SAML support to the Bottle Framework. index.py contains all the logic of the demo project, 'templates' is the Bottle templates of the project and 'saml' is a folder that contains the 'certs' folder that could be used to store the x509 public and private key, and the saml toolkit settings (settings.json and advanced_settings.json).

demo-flask

This folder contains a Flask project that will be used as demo to show how to add SAML support to the Flask Framework. 'index.py' is the main flask file that has all the code, this file uses the templates stored at the 'templates' folder. In the 'saml' folder we found the 'certs' folder to store the x509 public and private key, and the saml toolkit settings (settings.json and advanced_settings.json).

setup.py

Setup script is the centre of all activity in building, distributing, and installing modules. Read more at https://pythonhosted.org/an_example_pypi_project/setuptools.html

tests

Contains the unit test of the toolkit.

In order to execute the test you need to load the virtualenv with the toolkit installed on it and execute:

pip install -e ".[test]"

that will install dependences that the test requires.

and later execute:

python setup.py test

The previous line will run the tests for the whole toolkit. You can also run the tests for a specific module. To do so for the auth module you would have to execute this:

python setup.py test --test-suite tests.src.OneLogin.saml2_tests.auth_test.OneLogin_Saml2_Auth_Test

With the --test-suite parameter you can specify the module to test. You'll find all the module available and their class names at tests/src/OneLogin/saml2_tests/

How it works

Settings

First of all we need to configure the toolkit. The SP's info, the IdP's info, and in some cases, configure advanced security issues like signatures and encryption.

There are two ways to provide the settings information:

• Use a settings.json file that we should locate in any folder, but indicates its path with the 'custom_base_path' parameter.

• Use a json object with the setting data and provide it directly to the constructor of the class (if your toolkit integation requires certs, remember to provide the 'custom_base_path' as part of the settings or as a parameter in the constructor.

In the demo-django, demo-flask and demo-bottle folders you will find a 'saml' folder, inside there is a 'certs' folder and a settings.json and a advanced_settings.json files. Those files contain the settings for the saml toolkit. Copy them in your project and set the correct values.

This is the settings.json file:

{
    // If strict is True, then the Python Toolkit will reject unsigned
    // or unencrypted messages if it expects them to be signed or encrypted.
    // Also it will reject the messages if the SAML standard is not strictly
    // followed. Destination, NameId, Conditions ... are validated too.
    "strict": true,

    // Enable debug mode (outputs errors).
    "debug": true,

    // Service Provider Data that we are deploying.
    "sp": {
        // Identifier of the SP entity  (must be a URI)
        "entityId": "https://<sp_domain>/metadata/",
        // Specifies info about where and how the <AuthnResponse> message MUST be
        // returned to the requester, in this case our SP.
        "assertionConsumerService": {
            // URL Location where the <Response> from the IdP will be returned
            "url": "https://<sp_domain>/?acs",
            // SAML protocol binding to be used when returning the <Response>
            // message. OneLogin Toolkit supports this endpoint for the
            // HTTP-POST binding only.
            "binding": "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"
        },
        // If you need to specify requested attributes, set a
        // attributeConsumingService. nameFormat, attributeValue and
        // friendlyName can be omitted
        "attributeConsumingService": {
                "ServiceName": "SP test",
                "serviceDescription": "Test Service",
                "requestedAttributes": [
                    {
                        "name": "",
                        "isRequired": false,
                        "nameFormat": "",
                        "friendlyName": "",
                        "attributeValue": ""
                    }
                ]
        },
        // Specifies info about where and how the <Logout Response> message MUST be
        // returned to the requester, in this case our SP.
        "singleLogoutService": {
            // URL Location where the <Response> from the IdP will be returned
            "url": "https://<sp_domain>/?sls",
            // SAML protocol binding to be used when returning the <Response>
            // message. OneLogin Toolkit supports the HTTP-Redirect binding
            // only for this endpoint.
            "binding": "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"
        },
        // Specifies the constraints on the name identifier to be used to
        // represent the requested subject.
        // Take a look on src/onelogin/saml2/constants.py to see the NameIdFormat that are supported.
        "NameIDFormat": "urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified",
        // Usually x509cert and privateKey of the SP are provided by files placed at
        // the certs folder. But we can also provide them with the following parameters
        "x509cert": "",
        "privateKey": ""
    },

    // Identity Provider Data that we want connected with our SP.
    "idp": {
        // Identifier of the IdP entity  (must be a URI)
        "entityId": "https://app.onelogin.com/saml/metadata/<onelogin_connector_id>",
        // SSO endpoint info of the IdP. (Authentication Request protocol)
        "singleSignOnService": {
            // URL Target of the IdP where the Authentication Request Message
            // will be sent.
            "url": "https://app.onelogin.com/trust/saml2/http-post/sso/<onelogin_connector_id>",
            // SAML protocol binding to be used when returning the <Response>
            // message. OneLogin Toolkit supports the HTTP-Redirect binding
            // only for this endpoint.
            "binding": "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"
        },
        // SLO endpoint info of the IdP.
        "singleLogoutService": {
            // URL Location of the IdP where SLO Request will be sent.
            "url": "https://app.onelogin.com/trust/saml2/http-redirect/slo/<onelogin_connector_id>",
            // SAML protocol binding to be used when returning the <Response>
            // message. OneLogin Toolkit supports the HTTP-Redirect binding
            // only for this endpoint.
            "binding": "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"
        },
        // Public x509 certificate of the IdP
        "x509cert": "<onelogin_connector_cert>"
        /*
         *  Instead of using the whole x509cert you can use a fingerprint in order to
         *  validate a SAMLResponse, but you will need it to validate LogoutRequest and LogoutResponse using the HTTP-Redirect binding.
         *
         *  (openssl x509 -noout -fingerprint -in "idp.crt" to generate it,
         *  or add for example the -sha256 , -sha384 or -sha512 parameter)
         *
         *  If a fingerprint is provided, then the certFingerprintAlgorithm is required in order to
         *  let the toolkit know which algorithm was used. Possible values: sha1, sha256, sha384 or sha512
         *  'sha1' is the default value.
         *
         *  Notice that if you want to validate any SAML Message sent by the HTTP-Redirect binding, you
         *  will need to provide the whole x509cert.
         */
        // 'certFingerprint' => '',
        // 'certFingerprintAlgorithm' => 'sha1',
    }
}

In addition to the required settings data (idp, sp), extra settings can be defined in advanced_settings.json:

{
    // Security settings
    "security": {

        /** signatures and encryptions offered **/

        // Indicates that the nameID of the <samlp:logoutRequest> sent by this SP
        // will be encrypted.
        "nameIdEncrypted": false,

        // Indicates whether the <samlp:AuthnRequest> messages sent by this SP
        // will be signed.  [Metadata of the SP will offer this info]
        "authnRequestsSigned": false,

        // Indicates whether the <samlp:logoutRequest> messages sent by this SP
        // will be signed.
        "logoutRequestSigned": false,

        // Indicates whether the <samlp:logoutResponse> messages sent by this SP
        // will be signed.
        "logoutResponseSigned": false,

        /* Sign the Metadata
         false || true (use sp certs) || {
                                            "keyFileName": "metadata.key",
                                            "certFileName": "metadata.crt"
                                         }
        */
        "signMetadata": false,

        /** signatures and encryptions required **/

        // Indicates a requirement for the <samlp:Response>, <samlp:LogoutRequest>
        // and <samlp:LogoutResponse> elements received by this SP to be signed.
        "wantMessagesSigned": false,

        // Indicates a requirement for the <saml:Assertion> elements received by
        // this SP to be signed. [Metadata of the SP will offer this info]
        "wantAssertionsSigned": false,

        // Indicates a requirement for the <saml:Assertion>
        // elements received by this SP to be encrypted.
        'wantAssertionsEncrypted' => false,

        // Indicates a requirement for the NameID element on the SAMLResponse
        // received by this SP to be present.
        "wantNameId": true,

        // Indicates a requirement for the NameID received by
        // this SP to be encrypted.
        "wantNameIdEncrypted": false,

        // Indicates a requirement for the AttributeStatement element
        "wantAttributeStatement": true,

        // Authentication context.
        // Set to false and no AuthContext will be sent in the AuthNRequest,
        // Set true or don't present this parameter and you will get an AuthContext 'exact' 'urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport'
        // Set an array with the possible auth context values: array ('urn:oasis:names:tc:SAML:2.0:ac:classes:Password', 'urn:oasis:names:tc:SAML:2.0:ac:classes:X509'),
        'requestedAuthnContext': true,
        // Allows the authn comparison parameter to be set, defaults to 'exact' if the setting is not present.
        'requestedAuthnContextComparison': 'exact',

        // In some environment you will need to set how long the published metadata of the Service Provider gonna be valid.
        // is possible to not set the 2 following parameters (or set to null) and default values will be set (2 days, 1 week)
        // Provide the desired Timestamp, for example 2015-06-26T20:00:00Z
        'metadataValidUntil': null,
        // Provide the desired duration, for example PT518400S (6 days)
        'metadataCacheDuration': null,

        // Algorithm that the toolkit will use on signing process. Options:
        //    'http://www.w3.org/2000/09/xmldsig#rsa-sha1'
        //    'http://www.w3.org/2000/09/xmldsig#dsa-sha1'
        //    'http://www.w3.org/2001/04/xmldsig-more#rsa-sha256'
        //    'http://www.w3.org/2001/04/xmldsig-more#rsa-sha384'
        //    'http://www.w3.org/2001/04/xmldsig-more#rsa-sha512'
        'signatureAlgorithm' => 'http://www.w3.org/2000/09/xmldsig#rsa-sha1'
    },

    // Contact information template, it is recommended to supply
    // technical and support contacts.
    "contactPerson": {
        "technical": {
            "givenName": "technical_name",
            "emailAddress": "technical@example.com"
        },
        "support": {
            "givenName": "support_name",
            "emailAddress": "support@example.com"
        }
    },

    // Organization information template, the info in en_US lang is
    // recommended, add more if required.
    "organization": {
        "en-US": {
            "name": "sp_test",
            "displayname": "SP test",
            "url": "http://sp.example.com"
        }
    }
}

In the security section, you can set the way that the SP will handle the messages and assertions. Contact the admin of the IdP and ask them what the IdP expects, and decide what validations will handle the SP and what requirements the SP will have and communicate them to the IdP's admin too.

Once we know what kind of data could be configured, let's talk about the way settings are handled within the toolkit.

The settings files described (settings.json and advanced_settings.json) are loaded by the toolkit if not other dict with settings info is provided in the constructors of the toolkit. Let's see some examples.

# Initializes toolkit with settings.json & advanced_settings.json files.
auth = OneLogin_Saml2_Auth(req)
# or
settings = OneLogin_Saml2_Settings()

# Initializes toolkit with settings.json & advanced_settings.json files from a custom base path.
custom_folder = '/var/www/django-project'
auth = OneLogin_Saml2_Auth(req, custom_base_path=custom_folder)
# or
settings = OneLogin_Saml2_Settings(custom_base_path=custom_folder)

# Initializes toolkit with the dict provided.
auth = OneLogin_Saml2_Auth(req, settings_data)
# or
settings = OneLogin_Saml2_Settings(settings_data)

You can declare the settings_data in the file that constains the constructor execution or locate them in any file and load the file in order to get the dict available as we see in the following example:

filename = "/var/www/django-project/custom_settings.json" # The custom_settings.json contains a
json_data_file = open(filename, 'r')                      # settings_data dict.
settings_data = json.load(json_data_file)
json_data_file.close()

auth = OneLogin_Saml2_Auth(req, settings_data)

How load the library

In order to use the toolkit library you need to import the file that contains the class that you will need on the top of your python file.

from onelogin.saml2.auth import OneLogin_Saml2_Auth
from onelogin.saml2.settings import OneLogin_Saml2_Settings
from onelogin.saml2.utils import OneLogin_Saml2_Utils

The Request

Building an OneLogin_Saml2_Auth object requires a 'request' parameter.

auth = OneLogin_Saml2_Auth(req)

This parameter has the following scheme:

req = {
    "http_host": "",
    "script_name": "",
    "server_port": "",
    "get_data": "",
    "post_data": ""
}

Each python framework built its own request object, you may map its data to match what the saml toolkit expects. Let`s see some examples:

def prepare_from_django_request(request):
    return {
        'http_host': request.META['HTTP_HOST'],
        'script_name': request.META['PATH_INFO'],
        'server_port': request.META['SERVER_PORT'],
        'get_data': request.GET.copy(),
        'post_data': request.POST.copy()
    }

def prepare_from_flask_request(request):
    url_data = urlparse(request.url)
    return {
        'http_host': request.host,
        'server_port': url_data.port,
        'script_name': request.path,
        'get_data': request.args.copy(),
        'post_data': request.form.copy()
    }

Initiate SSO

In order to send an AuthNRequest to the IdP:

from onelogin.saml2.auth import OneLogin_Saml2_Auth

req = prepare_request_for_toolkit(request)
auth = OneLogin_Saml2_Auth(req)   # Constructor of the SP, loads settings.json
                                  # and advanced_settings.json

auth.login()      # Method that builds and sends the AuthNRequest

The AuthNRequest will be sent signed or unsigned based on the security info of the advanced_settings.json ('authnRequestsSigned').

The IdP will then return the SAML Response to the user's client. The client is then forwarded to the Attribute Consumer Service of the SP with this information.

We can set a 'return_to' url parameter to the login function and that will be converted as a 'RelayState' parameter:

target_url = 'https://example.com'
auth.login(return_to=target_url)

The login method can recieve 3 more optional parameters:

• force_authn When true the AuthNReuqest will set the ForceAuthn='true'
• is_passive When true the AuthNReuqest will set the Ispassive='true'
• set_nameid_policy When true the AuthNReuqest will set a nameIdPolicy element.

If a match on the future SAMLResponse ID and the AuthNRequest ID to be sent is required, that AuthNRequest ID must to be extracted and stored for future validation, we can get that ID by

auth.get_last_request_id()

The SP Endpoints

Related to the SP there are 3 important endpoints: The metadata view, the ACS view and the SLS view. The toolkit provides examples of those views in the demos, but lets see an example.

SP Metadata

This code will provide the XML metadata file of our SP, based on the info that we provided in the settings files.

req = prepare_request_for_toolkit(request)
auth = OneLogin_Saml2_Auth(req)
saml_settings = auth.get_settings()
metadata = saml_settings.get_sp_metadata()
errors = saml_settings.validate_metadata(metadata)
if len(errors) == 0:
    print metadata
else:
    print "Error found on Metadata: %s" % (', '.join(errors))

The get_sp_metadata will return the metadata signed or not based on the security info of the advanced_settings.json ('signMetadata').

Before the XML metadata is exposed, a check takes place to ensure that the info to be provided is valid.

Instead of using the Auth object, you can directly use

saml_settings = OneLogin_Saml2_Settings(settings=None, custom_base_path=None, sp_validation_only=True)

to get the settings object and with the sp_validation_only=True parameter we will avoid the IdP Settings validation.

Attribute Consumer Service(ACS)

This code handles the SAML response that the IdP forwards to the SP through the user's client.

req = prepare_request_for_toolkit(request)
auth = OneLogin_Saml2_Auth(req)
auth.process_response()
errors = auth.get_errors()
if not errors:
    if auth.is_authenticated():
        request.session['samlUserdata'] = auth.get_attributes()
        if 'RelayState' in req['post_data'] and
          OneLogin_Saml2_Utils.get_self_url(req) != req['post_data']['RelayState']:
            auth.redirect_to(req['post_data']['RelayState'])
        else:
            for attr_name in request.session['samlUserdata'].keys():
                print '%s ==> %s' % (attr_name, '|| '.join(request.session['samlUserdata'][attr_name]))
    else:
      print 'Not authenticated'
else:
    print "Error when processing SAML Response: %s" % (', '.join(errors))

The SAML response is processed and then checked that there are no errors. It also verifies that the user is authenticated and stored the userdata in session.

At that point there are 2 possible alternatives:

• If no RelayState is provided, we could show the user data in this view or however we wanted.
• If RelayState is provided, a rediretion take place.

Notice that we saved the user data in the session before the redirection to have the user data available at the RelayState view.

In order to retrieve attributes we use:

attributes = auth.get_attributes();

With this method we get a dict with all the user data provided by the IdP in the Assertion of the SAML Response.

If we execute print attributes we could get:

{
    "cn": ["Jhon"],
    "sn": ["Doe"],
    "mail": ["Doe"],
    "groups": ["users", "members"]
}

Each attribute name can be used as a key to obtain the value. Every attribute is a list of values. A single-valued attribute is a listy of a single element.

The following code is equivalent:

attributes = auth.get_attributes();
print attributes['cn']

print auth.get_attribute('cn')

Before trying to get an attribute, check that the user is authenticated. If the user isn't authenticated, an empty dict will be returned. For example, if we call to get_attributes before a auth.process_response, the get_attributes() will return an empty dict.

Single Logout Service (SLS)

This code handles the Logout Request and the Logout Responses.

delete_session_callback = lambda: request.session.flush()
url = auth.process_slo(delete_session_cb=delete_session_callback)
errors = auth.get_errors()
if len(errors) == 0:
    if url is not None:
        return redirect(url)
    else:
        print "Sucessfully Logged out"
else:
    print "Error when processing SLO: %s" % (', '.join(errors))

If the SLS endpoints receives a Logout Response, the response is validated and the session could be closed, using the callback.

# Part of the process_slo method
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')
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)

If the SLS endpoints receives an Logout Request, the request is validated, the session is closed and a Logout Response is sent to the SLS endpoint of the IdP.

# Part of the process_slo method
request = OneLogin_Saml2_Utils.decode_base64_and_inflate(self.__request_data['get_data']['SAMLRequest'])
if not OneLogin_Saml2_Logout_Request.is_valid(self.__settings, request, self.__request_data):
    self.__errors.append('invalid_logout_request')
else:
    if not keep_local_session:
        OneLogin_Saml2_Utils.delete_local_session(delete_session_cb)

    in_response_to = 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'] = OneLogin_Saml2_Constants.RSA_SHA1
        parameters['Signature'] = self.build_response_signature(logout_response, parameters.get('RelayState', None))

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

If we don't want that process_slo to destroy the session, pass a true parameter to the process_slo method

keepLocalSession = true
auth.process_slo(keep_local_session=keepLocalSession);

Initiate SLO

In order to send a Logout Request to the IdP:

The Logout Request will be sent signed or unsigned based on the security info of the advanced_settings.json ('logoutRequestSigned').

The IdP will return the Logout Response through the user's client to the Single Logout Service of the SP.

We can set a 'return_to' url parameter to the logout function and that will be converted as a 'RelayState' parameter:

target_url = 'https://example.com'
auth.logout(return_to=target_url)

Also there are 2 optional parameters that can be set:

• name_id. That will be used to build the LogoutRequest. If not name_id parameter is set and the auth object processed a SAML Response with a NameId, then this NameId will be used.
• session_index. SessionIndex that identifies the session of the user.

If a match on the LogoutResponse ID and the LogoutRequest ID to be sent is required, that LogoutRequest ID must to be extracted and stored for future validation, we can get that ID by

auth.get_last_request_id()

####Example of a view that initiates the SSO request and handles the response (is the acs target)####

We can code a unique file that initiates the SSO process, handle the response, get the attributes, initiate the slo and processes the logout response.

Note: Review the demos, in a later section we explain the demo use case further in detail.

req = prepare_request_for_toolkit(request)  # Process the request and build the request dict that
                                            # the toolkit expects

auth = OneLogin_Saml2_Auth(req)             # Initialize the SP SAML instance

if 'sso' in request.args:                   # SSO action (SP-SSO initited).  Will send an AuthNRequest to the IdP
    return redirect(auth.login())
elif 'sso2' in request.args:                       # Another SSO init action
    return_to = '%sattrs/' % request.host_url      # but set a custom RelayState URL
    return redirect(auth.login(return_to))
elif 'slo' in request.args:                     # SLO action. Will sent a Logout Request to IdP
    return redirect(auth.logout())
elif 'acs' in request.args:                 # Assertion Consumer Service
    auth.process_response()                     # Process the Response of the IdP
    errors = auth.get_errors()              # This method receives an array with the errors
    if len(errors) == 0:                    # that could took place during the process
        if not auth.is_authenticated():         # This check if the response was ok and the user
            msg = "Not authenticated"           # data retrieved or not (user authenticated)
        else:
            request.session['samlUserdata'] = auth.get_attributes()     # Retrieves user data
            self_url = OneLogin_Saml2_Utils.get_self_url(req)
            if 'RelayState' in request.form and self_url != request.form['RelayState']:
                return redirect(auth.redirect_to(request.form['RelayState']))   # Redirect if there is a relayState
            else:                           # If there is user data we save that to print it later.
                msg = ''
                for attr_name in request.session['samlUserdata'].keys():
                    msg += '%s ==> %s' % (attr_name, '|| '.join(request.session['samlUserdata'][attr_name]))
elif 'sls' in request.args:                                             # Single Logout Service
    delete_session_callback = lambda: session.clear()           # Obtain session clear callback
    url = auth.process_slo(delete_session_cb=delete_session_callback)   # Process the Logout Request & Logout Response
    errors = auth.get_errors()              #  Retrieves possible validation errors
    if len(errors) == 0:
        if url is not None:
            return redirect(url)
        else:
            msg = "Sucessfully logged out"

if len(errors) == 0:
  print msg
else:
  print ', '.join(errors)

Main classes and methods

Described below are the main classes and methods that can be invoked from the SAML2 library.

####OneLogin_Saml2_Auth - auth.py####

Main class of OneLogin Python Toolkit

• __init__ Initializes the SP SAML instance.
• login Initiates the SSO process.
• logout Initiates the SLO process.
• process_response Process the SAML Response sent by the IdP.
• process_slo Process the SAML Logout Response / Logout Request sent by the IdP.
• redirect_to Redirects the user to the url past by parameter or to the url that we defined in our SSO Request.
• is_authenticated Checks if the user is authenticated or not.
• get_attributes Returns the set of SAML attributes.
• get_attribute Returns the requested SAML attribute.
• get_nameid Returns the nameID.
• get_session_index Gets the SessionIndex from the AuthnStatement.
• get_session_expiration Gets the SessionNotOnOrAfter from the AuthnStatement.
• get_errors Returns a list with code errors if something went wrong.
• get_last_error_reason Returns the reason of the last error
• get_sso_url Gets the SSO url.
• get_slo_url Gets the SLO url.
• get_last_request_id The ID of the last Request SAML message generated.
• build_request_signature Builds the Signature of the SAML Request.
• build_response_signature Builds the Signature of the SAML Response.
• get_settings Returns the settings info.
• set_strict Set the strict mode active/disable.

####OneLogin_Saml2_Auth - authn_request.py####

SAML 2 Authentication Request class

• __init__ This class handles an AuthNRequest. It builds an AuthNRequest object.
• get_request Returns unsigned AuthnRequest.
• get_id Returns the AuthNRequest ID.

####OneLogin_Saml2_Response - response.py####

SAML 2 Authentication Response class

• __init__ Constructs the SAML Response object.
• is_valid Determines if the SAML Response is valid. Includes checking of the signature by a certificate.
• check_status Check if the status of the response is success or not
• get_audiences Gets the audiences
• get_issuers Gets the issuers (from message and from assertion)
• get_nameid_data Gets the NameID Data provided by the SAML Response from the IdP (returns a dict)
• get_nameid Gets the NameID provided by the SAML Response from the IdP (returns a string)
• get_session_not_on_or_after Gets the SessionNotOnOrAfter from the AuthnStatement
• get_session_index Gets the SessionIndex from the AuthnStatement
• get_attributes Gets the Attributes from the AttributeStatement element.
• validate_num_assertions Verifies that the document only contains a single Assertion (encrypted or not)
• validate_timestamps Verifies that the document is valid according to Conditions Element
• get_error After execute a validation process, if fails this method returns the cause

####OneLogin_Saml2_LogoutRequest - logout_request.py####

SAML 2 Logout Request class

• __init__ Constructs the Logout Request object.
• get_request Returns the Logout Request defated, base64encoded.
• get_id Returns the ID of the Logout Request. (If you have the object you can access to the id attribute)
• get_nameid_data Gets the NameID Data of the the Logout Request (returns a dict).
• get_nameid Gets the NameID of the Logout Request Message (returns a string).
• get_issuer Gets the Issuer of the Logout Request Message.
• get_session_indexes Gets the SessionIndexes from the Logout Request.
• is_valid Checks if the Logout Request recieved is valid.
• get_error After execute a validation process, if fails this method returns the cause.

####OneLogin_Saml2_LogoutResponse - logout_response.py####

SAML 2 Logout Response class

• __init__ Constructs a Logout Response object.
• get_issuer Gets the Issuer of the Logout Response Message
• get_status Gets the Status of the Logout Response.
• is_valid Determines if the SAML LogoutResponse is valid
• build Creates a Logout Response object.
• get_response Returns a Logout Response object.
• get_error After execute a validation process, if fails this method returns the cause.

####OneLogin_Saml2_Settings - settings.py####

Configuration of the OneLogin Python Toolkit

• __init__ Initializes the settings: Sets the paths of the different folders and Loads settings info from settings file or array/object provided.
• check_settings Checks the settings info.
• check_idp_settings Checks the IdP settings info.
• check_sp_settings Checks the SP settings info.
• get_errors Returns an array with the errors, the array is empty when the settings is ok.
• get_sp_metadata Gets the SP metadata. The XML representation.
• validate_metadata Validates an XML SP Metadata.
• get_base_path Returns base path.
• get_cert_path Returns cert path.
• get_lib_path Returns lib path.
• get_ext_lib_path Returns external lib path.
• get_schemas_path Returns schema path.
• check_sp_certs Checks if the x509 certs of the SP exists and are valid.
• get_sp_key Returns the x509 private key of the SP.
• get_sp_cert Returns the x509 public cert of the SP.
• get_idp_cert Returns the x509 public cert of the IdP.
• get_sp_data Gets the SP data.
• get_idp_data Gets the IdP data.
• get_security_data Gets security data.
• get_contacts Gets contacts data.
• get_organization Gets organization data.
• format_idp_cert Formats the IdP cert.
• format_sp_cert Formats the SP cert.
• format_sp_key Formats the private key.
• set_strict Activates or deactivates the strict mode.
• is_strict Returns if the 'strict' mode is active.
• is_debug_active Returns if the debug is active.

####OneLogin_Saml2_Metadata - metadata.py####

A class that contains functionality related to the metadata of the SP

• builder Generates the metadata of the SP based on the settings.
• sign_metadata Signs the metadata with the key/cert provided.
• add_x509_key_descriptors Adds the x509 descriptors (sign/encriptation) to the metadata

####OneLogin_Saml2_Utils - utils.py####

Auxiliary class that contains several methods

• decode_base64_and_inflate Base64 decodes and then inflates according to RFC1951.
• deflate_and_base64_encode Deflates and the base64 encodes a string.
• validate_xml Validates a xml against a schema.
• format_cert Returns a x509 cert (adding header & footer if required).
• format_private_key Returns a private key (adding header & footer if required).
• redirect Executes a redirection to the provided url (or return the target url).
• get_self_url_host Returns the protocol + the current host + the port (if different than common ports).
• get_self_host Returns the current host.
• is_https Checks if https or http.
• get_self_url_no_query Returns the URL of the current host + current view.
• get_self_routed_url_no_query Returns the routed URL of the current host + current view.
• get_self_url Returns the URL of the current host + current view + query.
• generate_unique_id Generates an unique string (used for example as ID for assertions).
• parse_time_to_SAML Converts a UNIX timestamp to SAML2 timestamp on the form yyyy-mm-ddThh:mm:ss(.s+)?Z.
• parse_SAML_to_time Converts a SAML2 timestamp on the form yyyy-mm-ddThh:mm:ss(.s+)?Z to a UNIX timestamp.
• now Returns unix timestamp of actual time.
• parse_duration Interprets a ISO8601 duration value relative to a given timestamp.
• get_expire_time Compares 2 dates and returns the earliest.
• query Extracts nodes that match the query from the Element.
• delete_local_session Deletes the local session.
• calculate_x509_fingerprint Calculates the fingerprint of a x509cert.
• format_finger_print Formates a fingerprint.
• generate_name_id Generates a nameID.
• get_status Gets Status from a Response.
• decrypt_element Decrypts an encrypted element.
• write_temp_file Writes some content into a temporary file and returns it.
• add_sign Adds signature key and senders certificate to an element (Message or Assertion).
• validate_sign Validates a signature (Message or Assertion).
• validate_binary_sign Validates signed bynary data (Used to validate GET Signature).
• def get_encoded_parameter Return an url encoded get parameter value
• extract_raw_query_parameter

####OneLogin_Saml2_IdPMetadataParser - idp_metadata_parser.py####

A class that contains methods to obtain and parse metadata from IdP

• get_metadata Get the metadata XML from the provided URL
• parse_remote Get the metadata XML from the provided URL and parse it, returning a dict with extracted data
• parse Parse the Identity Provider metadata and returns a dict with extracted data
• merge_settings Will update the settings with the provided new settings data extracted from the IdP metadata

For more info, look at the source code; each method is documented and details about what does and how to use it are provided. Make sure to also check the doc folder where HTML documentation about the classes and methods is provided.

Demos included in the toolkit

The toolkit includes 2 demos to teach how use the toolkit (A django and a flask project), take a look on it. Demos require that SP and IdP are well configured before test it, so edit the settings files.

Notice that each python framework has it own way to handle routes/urls and process request, so focus on how it deployed. New demos using other python frameworks are welcome as a contribution.

Getting Started

We said that this toolkit includes a django application demo and a flask applicacion demo, lets see how fast is deploy them.

Virtualenv

The use of a virtualenv is highly recommended.

Virtualenv helps isolating the python enviroment used to run the toolkit. You can find more details and an installation guide in the official documentation.

Once you have your virtualenv ready and loaded, then you can install the toolkit on it in development mode executing this:

 python setup.py develop

Using this method of deployment the toolkit files will be linked instead of copied, so if you make changes on them you won't need to reinstall the toolkit.

If you want install it in a normal mode, execute:

 python setup.py install

Demo Flask

You'll need a virtualenv with the toolkit installed on it.

To run the demo you need to install the requirements first. Load your virtualenv and execute:

 pip install -r demo-flask/requirements.txt

This will install flask and its dependences. Once it has finished, you have to complete the configuration of the toolkit. You'll find it at demo-flask/settings.json

Now, with the virtualenv loaded, you can run the demo like this:

 cd demo-flask
 python index.py

You'll have the demo running at http://localhost:8000

####Content####

The flask project contains:

• index.py Is the main flask file, where or the SAML handle take place.

• templates. Is the folder where flask stores the templates of the project. It was implemented a base.html template that is extended by index.html and attrs.html, the templates of our simple demo that shows messages, user attributes when available and login and logout links.

• saml Is a folder that contains the 'certs' folder that could be used to store the x509 public and private key, and the saml toolkit settings (settings.json and advanced_settings.json).

####SP setup####

The Onelogin's Python Toolkit allows you to provide the settings info in 2 ways: settings files or define a setting dict. In the demo-flask it used the first method.

In the index.py file we define the app.config['SAML_PATH'], that will target to the 'saml' folder. We require it in order to load the settings files.

First we need to edit the saml/settings.json, configure the SP part and review the metadata of the IdP and complete the IdP info. Later edit the saml/advanced_settings.json files and configure the how the toolkit will work. Check the settings section of this document if you have any doubt.

####IdP setup####

Once the SP is configured, the metadata of the SP is published at the /metadata url. Based on that info, configure the IdP.

####How it works####

1. First time you access to the main view 'http://localhost:8000', you can select to login and return to the same view or login and be redirected to /?attrs (attrs view).

2. When you click:

   2.1 in the first link, we access to /?sso (index view). An AuthNRequest is sent to the IdP, we authenticate at the IdP and then a Response is sent through the user's client to the SP, specifically the Assertion Consumer Service view: /?acs. Notice that a RelayState parameter is set to the url that initiated the process, the index view.

   2.2 in the second link we access to /?attrs (attrs view), we will expetience have the same process described at 2.1 with the diference that as RelayState is set the attrs url.

3. The SAML Response is processed in the ACS /?acs, if the Response is not valid, the process stops here and a message is shown. Otherwise we are redirected to the RelayState view. a) / or b) /?attrs

4. We are logged in the app and the user attributes are showed. At this point, we can test the single log out functionality.

The single log out funcionality could be tested by 2 ways.

5.1 SLO Initiated by SP. Click on the "logout" link at the SP, after that a Logout Request is sent to the IdP, the session at the IdP is closed and replies through the client to the SP with a Logout Response (sent to the Single Logout Service endpoint). The SLS endpoint /?sls of the SP process the Logout Response and if is valid, close the user session of the local app. Notice that the SLO Workflow starts and ends at the SP.

5.2 SLO Initiated by IdP. In this case, the action takes place on the IdP side, the logout process is initiated at the IdP, sends a Logout Request to the SP (SLS endpoint, /?sls). The SLS endpoint of the SP process the Logout Request and if is valid, close the session of the user at the local app and send a Logout Response to the IdP (to the SLS endpoint of the IdP). The IdP receives the Logout Response, process it and close the session at of the IdP. Notice that the SLO Workflow starts and ends at the IdP.

Notice that all the SAML Requests and Responses are handled at a unique view (index) and how GET paramters are used to know the action that must be done.

Demo Django

You'll need a virtualenv with the toolkit installed on it.

To run the demo you need to install the requirements first. Load your virtualenv and execute:

 pip install -r demo-django/requirements.txt

This will install django and its dependences. Once it has finished, you have to complete the configuration of the toolkit.

Later, with the virtualenv loaded, you can run the demo like this:

 cd demo-django
 python manage.py runserver 0.0.0.0:8000

You'll have the demo running at http://localhost:8000.

Note that many of the configuration files expect HTTPS. This is not required by the demo, as replacing these SP URLs with HTTP will work just fine. HTTPS is however highly encouraged, and left as an exercise for the reader for their specific needs.

If you want to integrate a production django application, take a look on this SAMLServiceProviderBackend that uses our toolkit to add SAML support: https://github.com/KristianOellegaard/django-saml-service-provider

####Content####

The django project contains:

• manage.py. A file that is automatically created in each Django project. Is a thin wrapper around django-admin.py that takes care of putting the project’s package on sys.path and sets the DJANGO_SETTINGS_MODULE environment variable.

• saml Is a folder that contains the 'certs' folder that could be used to store the x509 public and private key, and the saml toolkit settings (settings.json and advanced_settings.json).

• demo Is the main folder of the django project, that contains the typical files:

  • settings.py Contains the default parameters of a django project except the SAML_FOLDER parameter, that may contain the path where is located the 'saml' folder.
  • urls.py A file that define url routes. In the demo we defined '/' that is related to the index view, '/attrs' that is related with the attrs view and '/metadata', related to th metadata view.
  • views.py This file contains the views of the django project and some aux methods.
  • wsgi.py A file that let as deploy django using WSGI, the Python standard for web servers and applications.

• templates. Is the folder where django stores the templates of the project. It was implemented a base.html template that is extended by index.html and attrs.html, the templates of our simple demo that shows messages, user attributes when available and login and logout links.

####SP setup####

The Onelogin's Python Toolkit allows you to provide the settings info in 2 ways: settings files or define a setting dict. In the demo-django it used the first method.

After set the SAML_FOLDER in the demo/settings.py, the settings of the python toolkit will be loaded on the django web.

First we need to edit the saml/settings.json, configure the SP part and review the metadata of the IdP and complete the IdP info. Later edit the saml/advanced_settings.json files and configure the how the toolkit will work. Check the settings section of this document if you have any doubt.

####IdP setup####

Once the SP is configured, the metadata of the SP is published at the /metadata url. Based on that info, configure the IdP.

####How it works####

This demo works very similar to the flask-demo (We did it intentionally).