Make inResponseTo available in auth state (#1447)

Co-authored-by: Marko Ivančić <marko.ivancic@srce.hr>

docs/simplesamlphp-changelog.md

@@ -16,6 +16,7 @@ Released TBD
   * Fixed compatibility with Composer pre 1.8.5 (Debian 10) (#1427)
   * Updated npm dependencies up to February 1, 2021
   * Fixed a bug where it was impossible to set WantAssertionsSigned=true on SP-metadata (#1433)
+  * Make inResponseTo available in state array (#1447)
 
 ### authorize
   * Fix a bug in the Twig-template that causes an exception in Twig strict vars mode

modules/saml/www/sp/saml2-acs.php

@@ -261,6 +261,7 @@ if ($expire !== null) {
 $state['saml:sp:prevAuth'] = [
     'id'     => $response->getId(),
     'issuer' => $issuer,
+    'inResponseTo' => $response->getInResponseTo(),
 ];
 if (isset($state['\SimpleSAML\Auth\Source.ReturnURL'])) {
     $state['saml:sp:prevAuth']['redirect'] = $state['\SimpleSAML\Auth\Source.ReturnURL'];