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OneLogin's SAML Python Toolkit (compatible with Python3)

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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 Python3. There is a separate version that only support Python2: python-saml

Warning

Version 1.8.0 sets strict mode active by default

Update python3-saml to 1.5.0, this version includes security improvements for preventing XEE and Xpath Injections.

Update python3-saml to 1.4.0, this version includes a fix for the CVE-2017-11427 vulnerability.

This version also changes how the calculate fingerprint method works, and will expect as input a formatted X.509 certificate.

Update python3-saml to 1.2.6 that adds the use defusedxml that will prevent XEE and other attacks based on the abuse of XML. (CVE-2017-9672)

Update python3-saml to >= 1.2.1, 1.2.0 had a bug on signature validation process (when using wantAssertionsSigned and wantMessagesSigned). CVE-2016-1000251

1.2.0 version includes a security patch that contains extra validations that will prevent signature wrapping attacks.

python3-saml < v1.2.0 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 your Python application into a SP (Service Provider) that can be connected to an 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 web projects.

Installation

Dependencies

  • python 2.7 // python 3.6
  • xmlsec Python bindings for the XML Security Library.
  • isodate An ISO 8601 date/time/ duration parser and formatter
  • defusedxml XML bomb protection for Python stdlib modules

Review the setup.py file to know the version of the library that python3-saml is using

Code

Option 1. Download from GitHub

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

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 python3-saml package at https://pypi.python.org/pypi/python3-saml

You can install it executing:

$ pip install python3-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.

In production also we highly recommend to register on the settings the IdP certificate instead of using the fingerprint method. The fingerprint, is a hash, so at the end is open to a collision attack that can end on a signature validation bypass. Other SAML toolkits deprecated that mechanism, we maintain it for compatibility and also to be used on test environment.

Getting Started

Knowing the toolkit

The new OneLogin SAML Toolkit contains different folders (certs, lib, demo-django, demo-flask 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 X.509 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 X.509 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.

Use sp_new.crt if you are in a key rollover process and you want to publish that X.509 certificate on Service Provider metadata.

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-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 X.509 public and private key, and the SAML toolkit settings (settings.json and advanced_settings.json).

demo_pyramid

This folder contains a Pyramid project that will be used as demo to show how to add SAML support to the Pyramid Web Framework. \_\_init__.py is the main file that configures the app and its routes, views.py is where all the logic and SAML handling takes place, and the templates are stored in the templates folder. The saml folder is the same as in the other two demos.

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 only need to load the virtualenv with the toolkit installed on it and 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 and in the demo-flask folders you will find a saml folder, inside there is a certs folder and a settings.json and advanced_settings.json file. 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"
        },
        // 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"
        },
        // If you need to specify requested attributes, set a
        // attributeConsumingService. nameFormat, attributeValue and
        // friendlyName can be ommited
        "attributeConsumingService": {
                "serviceName": "SP test",
                "serviceDescription": "Test Service",
                "requestedAttributes": [
                    {
                        "name": "",
                        "isRequired": false,
                        "nameFormat": "",
                        "friendlyName": "",
                        "attributeValue": []
                    }
                ]
        },
        // 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 X.509 cert 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": ""

        /*
         * Key rollover
         * If you plan to update the SP X.509cert and privateKey
         * you can define here the new X.509cert and it will be
         * published on the SP metadata so Identity Providers can
         * read them and get ready for rollover.
         */
        // 'x509certNew': '',
    },

    // 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 X.509 certificate of the IdP
        "x509cert": "<onelogin_connector_cert>"
        /*
         *  Instead of using the whole X.509cert you can use a fingerprint in order to
         *  validate a SAMLResponse (but you still need the X.509cert to validate LogoutRequest and LogoutResponse using the HTTP-Redirect binding).
         *  But take in mind that the fingerprint, is a hash, so at the end is open to a collision attack that can end on a signature validation bypass,
         *  that why we don't recommend it use for production environments.
         *
         *  (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 X.509cert.
         */
        // "certFingerprint": "",
        // "certFingerprintAlgorithm": "sha1",

        /* In some scenarios the IdP uses different certificates for
         * signing/encryption, or is under key rollover phase and
         * more than one certificate is published on IdP metadata.
         * In order to handle that the toolkit offers that parameter.
         * (when used, 'X.509cert' and 'certFingerprint' values are
         * ignored).
         */
        // 'x509certMulti': {
        //      'signing': [
        //          '<cert1-string>'
        //      ],
        //      'encryption': [
        //          '<cert2-string>'
        //      ]
        // }
    }
}

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",
        // Set to true to check that the AuthnContext received matches the one requested.
        "failOnAuthnContextMismatch": false,

        // 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 desire TimeStamp, for example 2015-06-26T20:00:00Z
        "metadataValidUntil": null,
        // Provide the desire 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",

        // Algorithm that the toolkit will use on digest process. Options:
        //    'http://www.w3.org/2000/09/xmldsig#sha1'
        //    'http://www.w3.org/2001/04/xmlenc#sha256'
        //    'http://www.w3.org/2001/04/xmldsig-more#sha384'
        //    'http://www.w3.org/2001/04/xmlenc#sha512'
        'digestAlgorithm': "http://www.w3.org/2000/09/xmldsig#sha1"
    },

    // Contact information template, it is recommended to suply a
    // 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
    // recomended, 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 contains 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)

Metadata Based Configuration

The method above requires a little extra work to manually specify attributes about the IdP. (And your SP application)

There's an easier method -- use a metadata exchange. Metadata is just an XML file that defines the capabilities of both the IdP and the SP application. It also contains the X.509 public key certificates which add to the trusted relationship. The IdP administrator can also configure custom settings for an SP based on the metadata.

Using parse_remote IdP metadata can be obtained and added to the settings withouth further ado.

idp_data = OneLogin_Saml2_IdPMetadataParser.parse_remote('https://example.com/auth/saml2/idp/metadata')

If the Metadata contains several entities, the relevant EntityDescriptor can be specified when retrieving the settings from the IdpMetadataParser by its entityId value:

idp_data = OneLogin_Saml2_IdPMetadataParser.parse_remote(https://example.com/metadatas, entity_id='idp_entity_id')

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 a 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": "",

    # Advanced request options
    "https": "",
    "lowercase_urlencoding": "",
    "request_uri": "",
    "query_string": ""
}

Each Python framework builds 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()
    }

An explanation of some advanced request parameters:

  • https - Defaults to off. Set this to on if you receive responses over HTTPS.

  • lowercase_urlencoding - Defaults to false. ADFS users should set this to true.

  • request_uri - The path where your SAML server recieves requests. Set this if requests are not recieved at the server's root.

  • query_string - Set this with additional query parameters that should be passed to the request endpoint.

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 file (i.e. authnRequestsSigned).

The IdP will then return the SAML Response to the user's client. The client is then forwarded to the Attribute Consumer Service (ACS) 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 let's 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 redirection takes 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 (SLS) 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 another 5 optional parameters that can be set:

  • name_id: That will be used to build the LogoutRequest. If no 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.
  • nq: IDP Name Qualifier.
  • name_id_format: The NameID Format that will be set in the LogoutRequest.
  • spnq: The NameID SP NameQualifier will be set in the LogoutRequest.

If no name_id is provided, the LogoutRequest will contain a NameID with the entity Format. If name_id is provided and no name_id_format is provided, the NameIDFormat of the settings will be used.

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
    nameid = request.session['samlNameId']
    nameid_format = request.session['samlNameIdFormat']
    nameid_nq = request.session['samlNameIdNameQualifier']
    nameid_spnq = request.session['samlNameIdSPNameQualifier']
    session_index = request.session['samlSessionIndex']
    return redirect(auth.logout(None, nameid, session_index, nameid_nq, nameid_format, nameid_spnq))
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
            request.session['samlNameId'] = auth.get_nameid()
            request.session['samlNameIdFormat'] = auth.get_nameid_format()
            request.session['samlNameIdNameQualifier'] = auth.get_nameid_nq()
            request.session['samlNameIdSPNameQualifier'] = auth.get_nameid_spnq()
            request.session['samlSessionIndex'] = auth.get_session_index()
            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))

SP Key rollover

If you plan to update the SP x509cert and privateKey you can define the new x509cert as settings['sp']['x509certNew'] and it will be published on the SP metadata so Identity Providers can read them and get ready for rollover.

IdP with multiple certificates

In some scenarios the IdP uses different certificates for signing/encryption, or is under key rollover phase and more than one certificate is published on IdP metadata.

In order to handle that the toolkit offers the settings['idp']['x509certMulti'] parameter.

When that parameter is used, x509cert and certFingerprint values will be ignored by the toolkit.

The x509certMulti is an array with 2 keys:

  • signing: An array of certs that will be used to validate IdP signature
  • encryption: An array with one unique cert that will be used to encrypt data to be sent to the IdP.

Replay attacks

In order to avoid replay attacks, you can store the ID of the SAML messages already processed, to avoid processing them twice. Since the Messages expires and will be invalidated due that fact, you don't need to store those IDs longer than the time frame that you currently accepting.

Get the ID of the last processed message/assertion with the get_last_message_id/get_last_assertion_id method of the Auth object.

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 (AuthNRequest, LogoutRequest).
  • get_last_authn_contexts Returns the list of authentication contexts sent in the last SAML Response.
  • 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.
  • get_last_request_xml Returns the most recently-constructed/processed XML SAML request (AuthNRequest, LogoutRequest)
  • get_last_response_xml Returns the most recently-constructed/processed XML SAML response (SAMLResponse, LogoutResponse). If the SAMLResponse had an encrypted assertion, decrypts it.
  • get_last_message_id The ID of the last Response SAML message processed.
  • get_last_assertion_id The ID of the last assertion processed.
  • get_last_assertion_not_on_or_after The NotOnOrAfter value of the valid SubjectConfirmationData node (if any) of the last assertion processed (is only calculated with strict = true)

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.
  • get_xml Returns the XML that will be sent as part of the request.

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
  • get_xml_document Returns the SAML Response document (If contains an encrypted assertion, decrypts it).
  • get_id the ID of the response
  • get_assertion_id the ID of the assertion in the response
  • get_assertion_not_on_or_after the NotOnOrAfter value of the valid SubjectConfirmationData if any

OneLogin_Saml2_LogoutRequest - logout_request.py

SAML 2 Logout Request class

  • __init__ Constructs the Logout Request object.
  • get_request Returns the Logout Request deflated, base64-encoded.
  • 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.
  • get_xml Returns the XML that will be sent as part of the request or that was received at the SP

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.
  • get_xml Returns the XML that will be sent as part of the response or that was received at the SP

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 X.509 certs of the SP exists and are valid.
  • get_sp_key Returns the X.509 private key of the SP.
  • get_sp_cert Returns the X.509 public cert of the SP.
  • get_sp_cert_new Returns the future X.509 public cert of the SP.
  • get_idp_cert Returns the X.509 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_idp_cert_multi Formats all registered IdP certs.
  • format_sp_cert Formats the SP cert.
  • format_sp_cert_new Formats the SP cert new.
  • 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 X.509 descriptors (sign/encryption) 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.
  • format_cert Returns a X.509 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.
  • delete_local_session Deletes the local session.
  • calculate_X.509_fingerprint Calculates the fingerprint of a X.509 cert.
  • 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).

OneLogin_Saml2_XML- xml_utils.py

A class that contains methods to handle XMLs

  • to_string Serialize an element to an encoded string representation of its XML tree.
  • to_etree Parses an XML document or fragment from a string.
  • validate_xml Validates a xml against a schema
  • query Extracts nodes that match the query from the Element
  • extract_tag_text

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 application demo, let's see how fast is it to 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 dependencies. 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 X.509 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 uses 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 file, 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 functionality 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 parameters 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 dependencies. 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 X.509 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 the 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).

Getting up and running on Heroku

Getting python3-saml up and running on Heroku will require some extra legwork: python3-saml depends on python-xmlsec which depends on headers from the xmlsec1-dev Linux package to install correctly.

First you will need to add the apt buildpack to your build server:

heroku buildpacks:add --index=1 -a your-app heroku-community/apt
heroku buildpacks:add --index=2 -a your-app heroku/python

You can confirm the buildpacks have been added in the correct order with heroku buildpacks -a your-app, you should see the apt buildpack first followed by the Python buildpack.

Then add an Aptfile into the root of your repository containing the libxmlsec1-dev package, the file should look like:

libxmlsec1-dev

Finally, add python3-saml to your requirements.txt and git push to trigger a build.

Demo Pyramid

Unlike the other two projects, you don't need a pre-existing virtualenv to get up and running here, since Pyramid comes from the buildout school of thought.

To run the demo you need to install Pyramid, the requirements, etc.:

 cd demo_pyramid
 python3 -m venv env
 env/bin/pip install --upgrade pip setuptools
 env/bin/pip install -e ".[testing]"

If you want to make sure the tests pass, run:

 env/bin/pytest

Next, edit the settings in demo_pyramid/saml/settings.json. (Pyramid runs on port 6543 by default.)

Now you can run the demo like this:

 env/bin/pserve development.ini

If that worked, the demo is now running at http://localhost:6543.

Content

The Pyramid project contains:

  • __init__.py is the main Pyramid file that configures the app and its routes.

  • views.py is where all the SAML handling takes place.

  • templates is the folder where Pyramid stores the templates of the project. It was implemented a layout.jinja2 template that is extended by index.jinja2 and attrs.jinja2, 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 X.509 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 demo_pyramid the first method is used.

In the views.py file we define the SAML_PATH, which will target 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:6543), 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 experience 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 parameters are used to know the action that must be done.

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