* SAML/Univention: support for Univention SAML IdP for SSO incl. docu

2024-10-05 01:22:16 +02:00 · 2022-08-04 20:10:23 +02:00 · 2022-08-04 20:10:23 +02:00 · 3c4b03ca3c
commit 3c4b03ca3c
parent 7bcfdbfa5e
4 changed files with 268 additions and 14 deletions
--- a/api/src/Auth/Saml.php
+++ b/api/src/Auth/Saml.php
@ -42,6 +42,18 @@ use EGroupware\Api\Exception;
 * --> uses the login page for local accounts plus a button or selectbox (depending on number of IdPs) to start SAML login
 * c) multiple IdP and SAML configured as authentication method
 * --> SimpleSAML discovery/selection page with a checkbox to remember the selection (SSO after first selection)
+ *
+ * EGroupware understands assertions / attributes send after authentication in the following ways:
+ * - as "urn:uuid:<oid>" uri as used eg. in the DFN federation
+ * - as LDAP attribute name send eg. by Univention IdP (either lower cased or in matching camelCase)
+ *
+ * SAML support in EGroupware automatically downgrades session cookies to SameSite=Lax, as our default SameSite=Strict
+ * does NOT work with SAML redirects from an IdP in a different domain (browser simply ignores the session cookies)!
+ *
+ * Please note: the following SimpleSAMLphp WARNING can be safely ignored (as EGroupware shares the session with it):
+ * There is already a PHP session with the same name as SimpleSAMLphp's session, or the
+ * 'session.phpsession.cookiename' configuration option is not set. Make sure to set SimpleSAMLphp's cookie name
+ * with a value not used by any other applications.
 */
 class Saml implements BackendSSO
 {
@ -124,7 +136,10 @@ class Saml implements BackendSSO

 		// get attributes for (automatic) account creation
 		$attrs = $as->getAttributes();
-		$username = $attrs[self::usernameOid()][0];
+		if (!$attrs || empty($username = self::samlAttr(null, $attrs)))
+		{
+			throw new \Exception('Got NO '.(!$attrs ? 'attributes' : 'username attribute').' from SAML: '.json_encode($attrs));
+		}

 		// check if user already exists
 		if (!$GLOBALS['egw']->accounts->name2id($username, 'account_lid', 'u'))
@ -142,9 +157,9 @@ class Saml implements BackendSSO
 					return null;
 				}
 				$GLOBALS['auto_create_acct'] = [
-					'firstname' => $attrs[self::firstName][0],
-					'lastname' => $attrs[self::lastName][0],
-					'email' => $attrs[self::emailAddress][0],
+					'firstname' => self::samlAttr(self::firstName, $attrs),
+					'lastname' => self::samlAttr(self::lastName, $attrs),
+					'email' => self::samlAttr(self::emailAddress, $attrs),
 				];
 			}
 		}
@ -152,6 +167,12 @@ class Saml implements BackendSSO
 		// check affiliation / group to add or remove
 		self::checkAffiliation($username, $attrs, $GLOBALS['auto_create_acct']);

+		// Set SameSite attribute for cookies, as SAML redirect does NOT work with samesite=Strict,
+		// it requires as least Lax, otherwise the browser will ignore the session cookies set in Session::create()!
+		if ($GLOBALS['egw_info']['server']['cookie_samesite_attribute'] === 'Strict')
+		{
+			$GLOBALS['egw_info']['server']['cookie_samesite_attribute'] = 'Lax';
+		}
 		// return user session
 		return $GLOBALS['egw']->session->create($username, null, null, false, false);
 	}
@ -207,17 +228,17 @@ class Saml implements BackendSSO
 		switch($GLOBALS['egw_info']['server']['saml_join'])
 		{
 			case 'usernameemail':
-				if (!empty($attrs[self::emailAddress]))
+				if (!empty(self::samlAttr(self::emailAddress, $attrs)))
 				{
 					unset($update['account_email']);	// force email update
 				}
 			// fall through
 			case 'username':
-				$update['account_lid'] = $attrs[self::usernameOid()][0];
+				$update['account_lid'] = self::samlAttr(null, $attrs);
 				break;

 			case 'description':
-				$update['account_description'] = $attrs[self::usernameOid()][0];
+				$update['account_description'] = self::samlAttr(null, $attrs);
 				break;
 		}
 		// update other attributes
@ -227,9 +248,9 @@ class Saml implements BackendSSO
 			'account_lastname' => self::lastName,
 		] as $name => $oid)
 		{
-			if (!empty($attrs[$oid]) && ($name !== 'account_email' || empty($update['account_email'])))
+			if (!empty($value = self::samlAttr($oid, $attrs)) && ($name !== 'account_email' || empty($update['account_email'])))
 			{
-				$update[$name] = $attrs[$oid][0];
+				$update[$name] = $value;
 			}
 		}
 		// update account if necessary
@ -570,6 +591,60 @@ class Saml implements BackendSSO
 		return self::emailAddress;
 	}

+	/**
+	 * Get SAML attribute by name, taking into account that some IdP, like eg. Univention, use not the oid but the LDAP name
+	 *
+	 * @param string $name attribute name or null for the configured username
+	 * @param array $attrs as returned by SimpleSAML\Auth\Simple::getAttributes()
+	 * @param ?array $config default use config from $GLOBALS['egw_info']['server']
+	 * @return string[]|string|null
+	 */
+	private static function samlAttr($name, array $attrs, array $config=null)
+	{
+		if (!isset($config)) $config = $GLOBALS['egw_info']['server'];
+
+		switch($name ?: $config['saml_username'] ?? 'emailAddress')
+		{
+			case 'emailAddress':
+			case 'mailPrimaryAddress':
+			case self::emailAddress:
+				$keys = [self::emailAddress, 'emailAddress', 'mailPrimaryAddress'];
+				break;
+			case 'eduPersonPrincipalName':
+			case self::eduPersonPricipalName:
+				$keys = [self::eduPersonPricipalName, 'eduPersonPrincipalName'];
+				break;
+			case 'eduPersonUniqueId':
+			case self::eduPersonUniqueId:
+				$keys = [self::eduPersonUniqueId, 'eduPersonUniqueId'];
+				break;
+			case 'uid':
+			case self::uid:
+				$keys = [self::uid, 'uid'];
+				break;
+			case 'sn':
+			case 'surname':
+			case self::lastName:
+				$keys = [self::lastName, 'sn', 'surname'];
+				break;
+			case 'givenName':
+			case self::firstName:
+				$keys = [self::firstName, 'givenName'];
+				break;
+			case 'customOid':
+				$keys = ['urn:oid:'.$config['saml_username_oid'], $config['saml_username_oid']];
+				break;
+		}
+		foreach($keys as $key)
+		{
+			if (isset($attrs[$key]) || isset($attrs[$key = strtolower($key)]))
+			{
+				return count($attrs[$key]) === 1 ? current($attrs[$key]) : $attrs[$key];
+			}
+		}
+		return null;
+	}
+
 	/**
 	 * eduPersonAffiliation attribute
 	 */
@ -589,7 +664,7 @@ class Saml implements BackendSSO

 		// check if affiliation is configured and attribute returned by IdP
 		$attr = $config['saml_affiliation'] === 'eduPersonAffiliation' ? self::eduPersonAffiliation : $config['saml_affiliation_oid'];
-		if (!empty($attr) && !empty($attrs[$attr]) && !empty($config['saml_affiliation_group']) && !empty($config['saml_affiliation_values']) &&
+		if (!empty($attr) && !empty($affiliation = self::samlAttr($attr, $attrs)) && !empty($config['saml_affiliation_group']) && !empty($config['saml_affiliation_values']) &&
 			($gid = $GLOBALS['egw']->accounts->name2id($config['saml_affiliation_group'], 'account_lid', 'g')))
 		{
 			if (!isset($auto_create_acct) && ($accout_id = $GLOBALS['egw']->accounts->name2id($username, 'account_lid', 'u')))
@ -597,7 +672,7 @@ class Saml implements BackendSSO
 				$memberships = $GLOBALS['egw']->accounts->memberships($accout_id, true);
 			}
 			// check if attribute matches given values to add the extra membership
-			if (array_intersect($attrs[$attr], preg_split('/, */', $config['saml_affiliation_values'])))
+			if (array_intersect($affiliation, preg_split('/, */', $config['saml_affiliation_values'])))
 			{
 				if (isset($auto_create_acct))
 				{
--- a/api/src/Framework.php
+++ b/api/src/Framework.php
@ -254,7 +254,7 @@ abstract class Framework extends Framework\Extra

 		// run egw destructor now explicit, in case a (notification) email is send via Egw::on_shutdown(),
 		// as stream-wrappers used by Horde Smtp fail when PHP is already in destruction
-		$GLOBALS['egw']->__destruct();
+		if (isset($GLOBALS['egw'])) $GLOBALS['egw']->__destruct();
 		exit;
 	}

--- a/doc/UCS-SAML-SSO.md
+++ b/doc/UCS-SAML-SSO.md
@ -0,0 +1,169 @@
+## Configure EGroupware for SSO via SAML with Univention
+
+### SAML IdP need to be enabled, see [UCS Manual about login](https://docs.software-univention.de/manual/5.0/en/central-management-umc/login.html#central-management-umc-login)
+    
+* ```ucs-sso.<domain>``` need to resolve to one or more primary or secondary domain controllers
+* if you use LetsEncrypt, you should add the above domain to your certificate
+* UCS config registry variable ```portal/auth-mode``` has to be set to ```saml```
+* portal server needs to be restarted: ```systemctl restart univention-portal-server.service```
+
+### EGroupware needs to be configured for SAML via Setup (```https://egw.example.org/egroupware/setup/```)
+  * Login into setup with user ```admin``` and the password from ```/var/lib/egroupware/egroupware-docker-install.log```
+  * Go to [Edit current configuration]
+  
+<html>
+<table border="0" align="center" cellspacing="0" width="90%">
+<tbody>
+   <tr class="th">
+    <td colspan="2"><b>If using SAML 2.0 / Shibboleth / SimpleSAMLphp:</b></td>
+   </tr>
+
+   <tr class="row_off">
+    <td>Label to display as option on login page:<br>or leave empty and select SAML as authentication type above for single sign on</td>
+    <td><input name="newsettings[saml_discovery]" placeholder="University Login" value="Test SSO" size="20"></td>
+   </tr>
+
+   <tr class="row_on">
+    <td>Identity Provider:<br>You can specify multiple IdP on separate lines.</td>
+    <td><textarea name="newsettings[saml_idp]" placeholder="https://idp.uni-kl.de/idp/shibboleth" rows="3" cols="64">https://ucs.example.org/simplesamlphp/saml2/idp/metadata.php</textarea></td>
+   </tr>
+
+   <tr class="row_off">
+    <td>
+     Metadata:
+     refresh
+     <select name="newsettings[saml_metadata_refresh]">
+      <option value="daily">daily</option>
+      <option value="weekly">weekly</option>
+      <option value="no">not automatic</option>
+      <option value="now" selected>just now</option>
+     </select>
+    </td>
+    <td>
+     <input name="newsettings[saml_metadata]" placeholder="https://www.aai.dfn.de/fileadmin/metadata/dfn-aai-metadata.xml" value="https://ucs.example.org/simplesamlphp/saml2/idp/metadata.php" size="64"><br>
+    </td>
+   </tr>
+   <tr class="row_on">
+    <td>Certificate Metadata is signed with: (Will be downloaded once, unless changed.)</td>
+    <td><input name="newsettings[saml_certificate]" placeholder="https://www.aai.dfn.de/fileadmin/metadata/dfn-aai.pem" value="https://ucs.example.org/simplesamlphp/saml2/idp/certificate" size="64"></td>
+   </tr>
+   <tr class="row_off">
+    <td>Result data to use as username:</td>
+    <td>
+     <select name="newsettings[saml_username]">
+      <option value="eduPersonPrincipalName">eduPersonPrincipalName</option>
+      <option value="eduPersonUniqueId">eduPersonUniqueId</option>
+      <option value="emailAddress">emailAddress</option>
+      <option value="uid" selected="">uid</option>
+      <option value="customOid">custom OID</option>
+     </select>
+     <input name="newsettings[saml_username_oid]" value="" placeholder="urn:oid:x.x.x.x" size="40">
+    </td>
+   </tr>
+   <tr class="row_on">
+    <td>Result data to add or remove extra membership:</td>
+    <td>
+     <select name="newsettings[saml_affiliation]">
+      <option value="eduPersonAffiliation" selected="">eduPersonAffiliation</option>
+      <option value="custom">custom OID</option>
+     </select>
+     <input name="newsettings[saml_affiliation_oid]" value="" placeholder="urn:oid:x.x.x.x" size="40">
+    </td>
+   </tr>
+   <tr class="row_off">
+    <td>Result values (comma-separated) and group-name to add or remove:</td>
+    <td>
+     <input name="newsettings[saml_affiliation_values]" value="" placeholder="staff, ..." size="30">
+     <input name="newsettings[saml_affiliation_group]" value="" placeholder="Teachers" size="30">
+    </td>
+   </tr>
+   <tr class="row_on">
+    <td>Allow SAML logins to join existing accounts:<br>(Requires SAML optional on login page and user to specify username and password)</td>
+    <td>
+     <select name="newsettings[saml_join]">
+      <option value="">No</option>
+      <option value="usernameemail">Replace username and email</option>
+      <option value="username">Replace username and keep email</option>
+      <option value="description">Use account description to store SAML username</option>
+     </select>
+    </td>
+   </tr>
+   <tr class="row_off">
+    <td>Match SAML usernames to existing ones (use strings or regular expression):</td>
+    <td>
+      <input name="newsettings[saml_replace]" placeholder="replace: '@uni-kl.de' or '/@(uni-kl\.de)$/'" value="" size="40">
+      <input name="newsettings[saml_replace_with]" placeholder="with: '@rhrk.uni-kl.de' or '@rhrk.$1'" value="" size="35">
+   </td>
+   </tr>
+   <tr class="row_on" height="25">
+    <td>Some information for the own Service Provider metadata:</td>
+    <td><a href="/egroupware/saml/module.php/saml/sp/metadata.php/default-sp">Metadata URL</a></td>
+   </tr>
+   <tr class="row_off">
+    <td>Name for Service Provider:</td>
+    <td><input name="newsettings[saml_sp]" placeholder="EGroupware" value="EGroupware" size="40"></td>
+   </tr>
+   <tr class="row_on">
+    <td>Technical contact:</td>
+    <td>
+     <input name="newsettings[saml_contact_name]" value="Ralf Becker" placeholder="Name" size="24">
+     <input name="newsettings[saml_contact_email]" value="rb@egroupware.org" placeholder="Email" size="24">
+    </td>
+   </tr>
+</tbody></table>
+</html>
+
+> For Univention the Metadata-URL is also the ID of the IdP!
+
+### Configure EGroupware as service-provide in your UCS domain: **Domain > LDAP directory > SAML service provider**
+* Add: Type: SAML service provider
+
+```
+X Service provider activation status
+Service provider identifier: https://egw.example.org/egroupware/saml/module.php/saml/sp/metadata.php/default-sp
+Respond to this service provider URL after login: https://egw.example.org/egroupware/saml/module.php/saml/sp/saml2-acs.php/default-sp
+Single logout URL for this service provider: https://egw.example.org/egroupware/saml/module.php/saml/sp/saml2-logout.php/default-sp
+Format of NameID attribute:
+Name of the attribute that is used as NameID: uid
+Name of the organization for this service provider: EGroupware
+Description of this service provider:
+X Enable signed Logouts
+```
+* After saving the above, you have to edit the `Extended Settings` of your new Service Provide
+```
+X Allow transfering LDAP attributes to the Service Provider
+LDAP Attribute Name: uid
+LDAP Attribute Name: mailPrimaryAddress
+LDAP Attribute Name: givenName
+LDAP Attribute Name: sn
+```
+
+* Some useful links
+    * [How does Single Sign-on work?](https://www.univention.com/blog-en/2021/08/how-does-single-sign-on-work-with-saml-and-openidconnect/)
+    * [Reconfigure UCS Single Sign On](https://help.univention.com/t/reconfigure-ucs-single-sign-on/16161)
+    * [Create an SSO Login for Applications to Groups](https://www.univention.com/blog-en/2020/07/sso-login-for-groups/)
+    * [Adding a new external service provider](https://docs.software-univention.de/manual/5.0/en/domain-ldap/saml.html#domain-saml-additional-serviceprovider)
+
+### Configure EMail access without password
+
+> EGroupware normally use the session password to authenticate with the mail-server / Dovecot. If you use SSO (single sign on), EGroupware does not know your password and therefore can not pass it to the mail server.
+
+* login via ssh as user root to your mailserver
+* note the password from /etc/dovecot/master-users (secretpassword in the example below)
+```
+dovecotadmin:{PLAIN}secretpassword::::::
+```
+* add the following line to your /etc/dovecot/global-acls
+```shell
+echo "* user=dovecotadmin lra" >> /etc/dovecot/global-acls
+doveadm reload
+```
+* login with a user that has EGroupware admin rights
+* go to **Administration**, right-click on a user and select **mail-account**
+* in IMAP tab fill in the credentials:
+```
+Admin user: dovecotadmin
+Password:   secretpassword
+            X Use admin credentials to connect without a session-password, e.g. for SSO
+```
+* log out and in again with SSO and check everything works
--- a/saml/module.php
+++ b/saml/module.php
@ -7,4 +7,14 @@

 require_once('_include.php');

+try {
 	\SimpleSAML\Module::process()->send();
+}
+catch(\SimpleSAML\Error\NoState $e) {
+	// fix/hack NOSTATE error caused by EGroupware and therefore SimpleSAMLphp session lost due logout
+	if (strpos($_SERVER['PHP_SELF'], '/saml/module.php/saml/sp/saml2-logout.php/default-sp') !== false)
+	{
+		\EGroupware\Api\Egw::redirect(str_replace('/saml/module.php/saml/sp/saml2-logout.php/default-sp', '/logout.php', $_SERVER['PHP_SELF']));
+	}
+	throw $e;
+}