https://moodle.org/plugins/auth_saml2

100% Moodle SAML fast, simple, secure

• What is this?
• Why is it better?
• How does it work?
• Features
• Branches
• Installation
• Configuration
• Testing
• Debugging
• Gotchas
• Other SAML plugins
• Support
• Warm thanks

What is this?

This plugin does SAML authentication and user auto creation with field mapping.

Why is it better?

• 100% configured in the Moodle GUI - no installation of a whole separate app, and no touching of config files or generating certificates.
• Minimal configuration needed, in most cases just copy the IdP metadata in and then give the SP metadata to your IdP admin and that's it.
• Fast! - 3 redirects instead of 7
• Supports Single Logout via the HTTP-Redirect binding which many organisations require

How does it work?

It completely embeds a SimpleSamlPHP instance as an internal dependency, which is dynamically configured the way it should be by inheriting almost all of its configuration from Moodle configuration. In the future we should be able to swap to a different internal SAML implementation and the plugin GUI shouldn't need to change at all.

Features

• Dual login vs. forced login for all as an option, with ?saml=off on the login page for manual accounts, and ?saml=on supported everywhere to deep link and force login via SAML if dual auth is on.
• SAML attributes to Moodle user field mapping
• Automatic certificate creation
• Optionally auto create users
• Support for multiple identity providers
• IdP initiated flow / IdP first flow / IdP unsolicited logins, eg: http://idp.local/simplesaml/saml2/idp/SSOService.php?spentityid=http://moodle.local/auth/saml2/sp/metadata.php&RelayState=http://moodle.local/course/view.php?id=2

Features not yet implemented:

• Enrolment - this should be an enrol plugin and not in an auth plugin
• Role mapping - not yet implemented

Branches

Moodle version	Branch	PHP	SimpleSAMLphp
Moodle 3.9+	MOODLE_39_STABLE	7.4+	v2.0.5
Totara 13+	TOTARA_13_STABLE	7.4+	v2.0.5
Totara 12	TOTARA_12_STABLE	7.1 - 7.2	v1.19.1
Moodle 3.5 to 3.8	MOODLE_35_STABLE	7.2+	v1.18.8
Moodle 2.7 to 3.4	27_34STABLE	5.5+	v1.15.4
Totara up to 11	27_34STABLE	5.5+	v1.15.4

Installation

1. Install the plugin the same as any standard Moodle plugin, either via the Moodle plugin directory, or you can use git to clone it into your source:

   git clone git@github.com:catalyst/moodle-auth_saml2.git auth/saml2

2. Then run the Moodle upgrade

3. If your IdP has a publicly available XML descriptor, copy its URL into the SAML2 auth config settings page. Otherwise copy the XML verbatim into the settings textarea instead.

4. If your IdP requires whitelisting each SP, use the links in the settings page to download the XML, or you can provide that URL to your IdP administrator.

For most simple setups, this is enough to get authentication working. There are many more settings to define how to handle new accounts, dual authentication, and to easily debug the plugin if things are not working.

Configuration

For setting up a new SAML integration, see the Quick Start Guide.

Most of the configuration is done in the Moodle admin GUI and should be self explanatory for someone familiar with SAML generally. There are a few extra configuration items which currently don't have a GUI and should be added to your Moodle config.php file:

$CFG->auth_saml2_disco_url = '';
$CFG->auth_saml2_store = '\\auth_saml2\\redis_store'; # Use an alternate store
$CFG->auth_saml2_redis_server = ''; # Required for the redis_store above

Testing

This plugin has been tested against:

• SimpleSamlPHP set up as an IdP
• openidp.feide.no
• testshib.org
• An AAF instance of Shibboleth
• OpenAM (Sun / Oracle)
• Microsoft ADFS
• NetIQ Access Manager

To configure this against testshib you will need a moodle which is publicly accessible over the internet. Turn on the SAML2 plugin and then configure it:

Home ► Site administration ► Plugins ► Authentication ► SAML2

1. Set the Idp URL to: https://www.testshib.org/metadata/testshib-providers.xml
2. Set dual auth to Yes
3. Set auto create users to Yes
4. Click on 'Download SP Metadata'
5. Save the settings
6. Upload that file to: https://www.testshib.org/register.html
7. Logout and login, you should see 'TestShib Test IdP' as an alternate login method and be able to login via the example credentials.

Debugging

If you are having any issues, turn on debugging inside the SAML2 auth plugin, as well as turning on the Moodle level debugging. This will give in depth debugging on the SAML XML and errors, as well as stack traces. Please include this in any GitHub issue you create if you are having trouble.

There is also a stand-alone test page which authenticates but isn't a 'Moodle' page. All this page does is echo the SAML attributes which have been provided by the IDP. This can be very handy for setting up the mappings, e.g. when the IDP might be providing the right attributes but under an unexpected key name.

/auth/saml2/test.php

If you can succesfully do a SAML login using this page then it narrows down where the issues lie. Some common issues are:

1. You received a valid set of SAML attributes, but the attribute(s) needed are not present. For example, often in ADFS configuration you may need to 'release' the username.

2. You have got a valid set of attributes, but the key for the username isn't what you expected. Cut and paste the correct key name into the Moodle auth saml2 config page to correctly map the 'idpattr' value.

3. The attribute key name might be a really crazy long looking string. This is common with ADFS. If that long string contains certain characters then Moodle will not accept it, and this is an issue in Moodle itself and applies to all auth plugins. You can add a custom claim in ADFS to rename this attribute to something nicer. See: GitHub issue #124.

4. If it is bringing across all the attributes properly, but you are getting: "You have logged in succesfully as 'xyz' but do not have an account in Moodle" then you either need to change your user provisioning process to ensure users are created ahead of time, or you need to enable the autocreate setting. If you do auto create then you need to be very careful that auto-created users, and users provisioned via other means, are set up consistently.

Gotchas

Bitnami Moodle

We get lots of complaints in many plugins that end up being issues with Bitnami. It does a very poor job and does not properly configure Moodle with some quite basic things and we strongly recommend you don't use it at all, not just for SAML issues. In particular it dynamically detects the domain that Moodle is on, which is not supported by Moodle. $CFG->wwwroot MUST be manually set to a static value in config.php.

Multiple IdPs

When using multiple IdPs the system will force enable the dual login setting. This is so that a list of possible identity providers will be presented to the user when logging in.

To enable multiple IdPs you can use the 'IdP metadata XML OR public XML URL' configuration field. An example might look like this:

Identity Provider Name https://ssp1.local/simplesaml/saml2/idp/metadata.php
https://ssp2.local/simplesaml/saml2/idp/metadata.php

If there is any text before the https scheme then it will be used as the override name.

It is not be recommended to use the 'IdP label override' configuration option with multiple IdPs.

Deep linking saml=on URL parameter

For most use cases, this parameter should work on all supported Moodle versions. However, to make this paramater force a SAML login redirect, even when users are already logged in as a guest, we use a Moodle hook that is only available in Moodle >= 3.8.

To make guest user redirecting work on moodle 3.7 and below, you will need to backport the changes from MDL-66340.

OpenAM

If you are getting signature issues with OpenAM then you may need to manually yank out the contents of the ds:X509Certificate element into a file and then import it into OpenAM's certificate store:

$ cat moodle.edu.crt
-----BEGIN CERTIFICATE-----
thesuperlongcertificatestringgoeshere=
-----END CERTIFICATE-----
$ keytool -import -trustcacerts -alias moodle.edu -file moodle.edu.crt -keystore keystore.jks

Then follow the prompts and restart OpenAM.

Certificate Locking

It is possible to lock the certificates in the admin UI which prevents inadvertent overwriting of them. They can also be unlocked in the UI. If you really want to protect them, chown the files so that your webserver user cannot modify them at all.

These certificates are located in the $CFG->dataroot/saml2 directory.

To manually unlock the certificates please restore the write permissions to the required files.

$ cd $CFG->dataroot/saml2
$ chmod 0660 site.example.crt
$ chmod 0660 site.example.pem

Windows configuration for OpenSSL

Some environments, particularly Windows-based, may not provide an OpenSSL configuration file at the default location, producing errors like the following when regenerating certificates:

error:02001003:system library:fopen:No such process
error:2006D080:BIO routines:BIO_new_file:no such file
error:0E064002:configuration file routines:CONF_load:system lib

You may also see OpenSSL errors in various Moodle screens (including the admin page) related to the auth_saml2 plugin. For example:

Warning: openssl_csr_sign(): cannot get CSR from parameter 1 in
C:\path\to\moodle\auth\saml2\setuplib.php

There are two ways to resolve this problem (you only need to do one of these, the first is probably more sensible):

1. Set the OPENSSL_CONF environment variable to point to the full path and location of an openssl.cnf file (e.g. C:\tools\php73\extras\ssl\openssl.cnf) and restart Apache.

2. (for PHP versions <= 7.3) Make a copy of that openssl.cnf file in the location C:\usr\local\ssl\openssl.cnf.

OKTA configuration

Okta has some weird names for settings which are confusing, this may help decipher them:

Okta name	Sane name	Value
Single sign on URL	ACS URL	https://example.com/auth/saml2/sp/saml2-acs.php/example.com
Audience URI	Entity ID	https://example.com/auth/saml2/sp/metadata.php
Enable Single Log Out	Enable Single Log Out	True
Single Logout URL	Single Logout URL	https://example.com/auth/saml2/sp/saml2-logout.php/example.com
Assertion Encryption	Assertion Encryption	Encrypted

Suggested attribute mappings:

Name	Value
Login	user.login
FirstName	user.firstName
LastName	user.lastName
Email	user.email

Auth Proc Filter Hooks

Other plugins may hook into SAML2 and create custom Auth Proc Filters. Auth Proc Filters allow you to mutate the attributes passed back from the IdP before Moodle handles them and maps them to profile fields.

Steps to implement the hook:

1. Create a plugin that will implement the hook (e.g local_hookimplement)
2. Define the hook function local_hookimplement_extend_auth_saml2_proc in the plugin's lib.php file.
3. The function should return an array of SimpleSaml Auth Proc Filters.

Examples:

function local_hookimplement_extend_auth_saml2_proc() {
   return [
      52 => array(
         'class' => 'core:AttributeMap',
         'oid2name'
      )
   ]
}

Custom code:

function local_hookimplement_extend_auth_saml2_proc() {
   return [
      51 => array(
         'class' => 'core:PHP',
         'code' => '$attributes = update_attributes($attributes)'
      )
   ]
}

function update_attributes($attributes) {
   if (isset($attributes["uid"])) {
      $attributes["uid"] => $attributes["username"];
   }
   return $attributes;
}

Multiple IdP filter:

function local_hookimplement_extend_auth_saml2_proc() {
   return [
      51 => array(
         'class' => 'core:PHP',
         'code' => '$attributes = update_attributes($attributes)'
      ),
   ]
}

function update_attributes($attributes) {
   global $SESSION, $saml2auth;
    $idps = $saml2auth->metadataentities;
    foreach ($idps as $idp) {
        foreach ($idp as $key => $value) {
            if ($SESSION->saml2idp == $key) {
                $alias = $idp[$key]->alias;
            }

            if ($alias == 'idp_alias') {
                $attributes["uid"] = $attributes['username'];
            }
        }
    }
}

Other SAML plugins

The diversity and variable quality and features of SAML moodle plugins is a reflection of a great need for a solid SAML plugin, but the neglect to do it properly in core. SAML2 is by far the most robust and supported protocol across the internet and should be fully integrated into Moodle core as both a Service Provider and as an Identity Provider, and without any external dependencies to manage.

Here is a quick run down of the alternatives:

Moodle Core

• auth/shibboleth - This requires a separately installed and configured Shibboleth install.

  One big issue with this, and the category below, is the extra application between Moodle and the IdP, so the login and logout processes have more latency due to extra redirects. Latency on potentially slow mobile networks is by far the biggest bottleneck for login speed, and the biggest complaint by end users in our experience.

• auth/oauth2

  OAuth2 has direct support in Moodle.

Plugins that require SimpleSamlPHP

These are all forks of each other, and unfortunately have diverged quite early or have no common git history, making it difficult to cross port features or fixes between them.

• moodle.org/plugins/auth_saml

• moodle.org/plugins/auth_zilink_saml

• github.com/piersharding/moodle-auth_saml

Plugins which embed a SAML client library

These are generally much easier to manage and configure as they are standalone.

• moodle.org/plugins/auth_onelogin_saml - This one uses its own embedded SAML library which is great and promising, however it doesn't support 'back channel logout' which is critical for security in any large organisation.

• This auth_saml2 plugin, with an embedded and dynamically configured SimpleSamlPHP instance under the hood.

Support

If you have issues please log them in GitHub.

Please note our time is limited, so if you need urgent support or want to sponsor a new feature then please contact Catalyst IT Australia.

Warm thanks

Thanks to the various authors and contributors to the other plugins above.

Thanks to La Trobe University in Melbourne for sponsoring the initial creation of this plugin.

Thanks to Centre de gestion informatique de l’éducation (CGIE) in Luxembourg for sponsoring the user autocreation and field mapping work.

This plugin was developed by Catalyst IT Australia.