added support for conditional LOA

Author: doedje

docs/stepupsfo.md

@@ -96,3 +96,28 @@ running the SFO service:
 - The entityid and certificate configured in the authsource above.
 - The namespace of the subjectattribute you're using (likely something like `urn:collab:person:example.org:`).
 - The AssertionConsumerService location: `<your ssp base url>/module.php/stepupsfo/acs.php`.
+
+Conditional LOA
+---------------
+
+In addition to setting the `loa` setting for the authproc's config, you can also add an extra `loa` attribute to the user's attributes, for instance by adding the attribute to the LDAP or setting it using core:PHP or any other auth proc. You should of course make sure you put this auth proc before your SFO-related auth procs.
+
+Example:
+
+```php
+    'authproc' => [
+        23 => [
+            'class' => 'core:PHP',
+            'code' => '
+                if (someCondition) {
+                    $attributes["loa"] = "http://test.surfconext.nl/assurance/sfo-level3";
+                } else {
+                    $attributes["loa"] = "http://test.surfconext.nl/assurance/sfo-level1.5";
+                }
+            '
+        ],
+    ],
+    // other authprocs for SFO
+```
+
+The `loa` set in the authproc config is used as the default (optional). The `loa` set in the user's attributes will take precedence. Setting the `loa` to an empty string will skip the SFO. Not setting the `loa` will result in an error.

src/Auth/Process/SFO.php

@@ -17,6 +17,7 @@
 use SimpleSAML\Module;
 use SimpleSAML\Module\saml\Message;
 
+use function array_key_exists;
 use function in_array;
 use function sprintf;
 use function substr;
@@ -33,6 +34,9 @@ class SFO extends Auth\ProcessingFilter
     /** @var \SimpleSAML\Configuration */
     private Configuration $idpMetadata;
 
+    /** @var array */
+    private array $config = [];
+
     /** @var string */
     private string $subjectidattribute;
 
@@ -57,9 +61,8 @@ public function __construct(array $config, $reserved)
 
         $this->idpMetadata = $this->getIdPMetadata($config['idpEntityid']);
 
-        $config['AuthnContextClassRef'] = $config['loa'];
         $config['entityid'] = $config['entityID'];
-        $this->metadata = Configuration::loadFromArray($config);
+        $this->config = $config;
     }
 
 
@@ -77,6 +80,24 @@ public function process(array &$state): void
             }
         }
 
+        if (array_key_exists('loa', $state['Attributes'])) {
+            // LOA is present in User's attributes
+            $loa = $state['Attributes']['loa'];
+        } else if (array_key_exists('loa', $this->config)) {
+            // LOA set in SFO config is default.
+            $loa = $this->config['loa'];
+        } else {
+            throw new Exception("SFO - No LOA set.");
+        }
+        if (empty($loa)) {
+            // LOA is set to an empty string, skip SFO
+            return;
+        }
+        Logger::info('SFO - requested LOA: ' . $loa);
+
+        $this->config['AuthnContextClassRef'] = $loa;
+        $this->metadata = Configuration::loadFromArray($this->config);
+
         $state['sfo:sp:metadata'] = $this->metadata;
         $state['sfo:idp:entityid'] = $this->idpMetadata->getString('entityid');
         $samlstateid = Auth\State::saveState($state, 'stepupsfo:pre');