diff --git a/modules/authX509/dictionaries/X509warning.definition.json b/modules/authX509/dictionaries/X509warning.definition.json
new file mode 100644
index 0000000000000000000000000000000000000000..4770dcf2c34175b7835eda6dbe09ce68b981644d
--- /dev/null
+++ b/modules/authX509/dictionaries/X509warning.definition.json
@@ -0,0 +1,11 @@
+{
+ "warning": {
+ "en": "Your certificate will expire in %days% days. Please renew your certificate in time."
+ },
+ "warning_header": {
+ "en": "Your certificate is about to expire."
+ },
+ "proceed": {
+ "en": "Proceed"
+ }
+}
diff --git a/modules/authX509/dictionaries/X509warning.translation.json b/modules/authX509/dictionaries/X509warning.translation.json
new file mode 100644
index 0000000000000000000000000000000000000000..11ac94b55ae76fb7113f032220c761d8cf48ef03
--- /dev/null
+++ b/modules/authX509/dictionaries/X509warning.translation.json
@@ -0,0 +1,11 @@
+{
+ "warning": {
+ "nl": "Je certificaat verloopt over %days% dagen. Vervang tijdig je certificaat."
+ },
+ "warning_header": {
+ "nl": "Je certificaat verloopt binnenkort."
+ },
+ "proceed": {
+ "nl": "Verder"
+ }
+}
diff --git a/modules/authX509/docs/authX509.txt b/modules/authX509/docs/authX509.txt
index 8cb3ff352fe044ccd0e4a1d7bdf0f009e1afc188..f37c8ee2574a571ac8df2851b9b4eebdc55789ec 100644
--- a/modules/authX509/docs/authX509.txt
+++ b/modules/authX509/docs/authX509.txt
@@ -106,3 +106,17 @@ can hack your metadata/saml20-idp-hosted.php file that way:
'urn:oasis:names:tc:SAML:2.0:attrname-format:uri',
)
+Checking certificate expiry
+===========================
+
+To issue warnings to users whos certificate is about to expire, configure an authproc filter.
+
+Example:
+
+ 10 => array(
+ 'class' => 'authX509:ExpiryWarning',
+ 'warndaysbefore' => '30',
+ ),
+
+Parameter `warndaysbefore` specifies the number of days the user's certificate needs to be valid before a warning is
+issued. The default is 30.
\ No newline at end of file
diff --git a/modules/authX509/lib/Auth/Process/ExpiryWarning.php b/modules/authX509/lib/Auth/Process/ExpiryWarning.php
new file mode 100644
index 0000000000000000000000000000000000000000..f9dedf573693ad2f81e331c2bf1cb724ebb520a6
--- /dev/null
+++ b/modules/authX509/lib/Auth/Process/ExpiryWarning.php
@@ -0,0 +1,84 @@
+<?php
+
+/**
+ * Filter which shows a warning if the user's client certificate is about to expire.
+ *
+ ** <code>
+ * // show about2xpire warning if client certificate is about to expire
+ * 10 => array(
+ * 'class' => 'authX509:ExpiryWarning',
+ * 'warndaysbefore' => '30',
+ * ),
+ * </code>
+ *
+ * @author Joost van Dijk, SURFnet. <Joost.vanDijk@surfnet.nl>
+ * @package simpleSAMLphp
+ */
+class sspmod_authX509_Auth_Process_ExpiryWarning extends SimpleSAML_Auth_ProcessingFilter {
+
+ private $warndaysbefore = 30;
+
+ /**
+ * Initialize this filter.
+ *
+ * @param array $config Configuration information about this filter.
+ * @param mixed $reserved For future use.
+ */
+ public function __construct($config, $reserved) {
+ parent::__construct($config, $reserved);
+
+ assert('is_array($config)');
+
+ if (array_key_exists('warndaysbefore', $config)) {
+ $this->warndaysbefore = $config['warndaysbefore'];
+ if (!is_string($this->warndaysbefore)) {
+ throw new Exception('Invalid value for \'warndaysbefore\'-option to authX509::ExpiryWarning filter.');
+ }
+ }
+ }
+
+ /**
+ * Process an authentication response.
+ *
+ * This function saves the state, and if necessary redirects the user to the page where the user
+ * is informed about the expiry date of his/her certificate.
+ *
+ * @param array $state The state of the response.
+ */
+ public function process(&$state) {
+ assert('is_array($state)');
+
+ if (isset($state['isPassive']) && $state['isPassive'] === TRUE) {
+ /* We have a passive request. Skip the warning. */
+ return;
+ }
+
+ if (!isset($_SERVER['SSL_CLIENT_CERT']) ||
+ ($_SERVER['SSL_CLIENT_CERT'] == '')) {
+ return;
+ }
+
+ $client_cert = $_SERVER['SSL_CLIENT_CERT'];
+ $client_cert_data = openssl_x509_parse($client_cert);
+ if ($client_cert_data == FALSE) {
+ SimpleSAML_Logger::error('authX509: invalid cert');
+ return;
+ }
+ $validTo = $client_cert_data['validTo_time_t'];
+ $now = time();
+ $daysleft = (int)(($validTo - $now) / (24*60*60));
+ if ($daysleft > $this->warndaysbefore) {
+ /* We have a certificate that will be valid for some time. Skip the warning. */
+ return;
+ }
+
+ SimpleSAML_Logger::warning('authX509: user certificate expires in ' . $daysleft . ' days');
+ $state['daysleft'] = $daysleft;
+
+ /* Save state and redirect. */
+ $id = SimpleSAML_Auth_State::saveState($state, 'warning:expire');
+ $url = SimpleSAML_Module::getModuleURL('authX509/expirywarning.php');
+ \SimpleSAML\Utils\HTTP::redirectTrustedURL($url, array('StateId' => $id));
+ }
+
+}
diff --git a/modules/authX509/templates/X509warning.php b/modules/authX509/templates/X509warning.php
new file mode 100644
index 0000000000000000000000000000000000000000..b391ddda2368b2b9256d728d98aedc8990a5beb5
--- /dev/null
+++ b/modules/authX509/templates/X509warning.php
@@ -0,0 +1,41 @@
+<?php
+
+/**
+ * Template form for X509 warnings.
+ *
+ * Parameters:
+ * - 'target': Target URL for the continue-button.
+ * - 'data': Parameters which should be included in the request.
+ *
+ * @package simpleSAMLphp
+ */
+
+$warning = $this->t('{authX509:X509warning:warning}', array(
+ '%days%' => htmlspecialchars($this->data['daysleft']),
+));
+
+$this->data['header'] = $this->t('{authX509:X509warning:warning_header}');
+$this->data['autofocus'] = 'proceedbutton';
+
+$this->includeAtTemplateBase('includes/header.php');
+
+?>
+
+<form style="display: inline; margin: 0px; padding: 0px" action="<?php echo htmlspecialchars($this->data['target']); ?>">
+
+ <?php
+ // Embed hidden fields...
+ foreach ($this->data['data'] as $name => $value) {
+ echo('<input type="hidden" name="' . htmlspecialchars($name) . '" value="' . htmlspecialchars($value) . '" />');
+ }
+ ?>
+ <p><?php echo $warning; ?></p>
+
+ <input type="submit" name="proceed" id="proceedbutton" value="<?php echo htmlspecialchars($this->t('{authX509:X509warning:proceed}')) ?>" />
+
+</form>
+
+
+<?php
+
+$this->includeAtTemplateBase('includes/footer.php');
diff --git a/modules/authX509/www/expirywarning.php b/modules/authX509/www/expirywarning.php
new file mode 100644
index 0000000000000000000000000000000000000000..f09a425ccdaf6f2c0806eadd623dcec73f954b1e
--- /dev/null
+++ b/modules/authX509/www/expirywarning.php
@@ -0,0 +1,29 @@
+<?php
+
+/**
+ * This script warns a user that his/her certificate is about to expire.
+ *
+ * @package simpleSAMLphp
+ */
+
+SimpleSAML_Logger::info('AuthX509 - Showing expiry warning to user');
+
+if (!array_key_exists('StateId', $_REQUEST)) {
+ throw new SimpleSAML_Error_BadRequest('Missing required StateId query parameter.');
+}
+$id = $_REQUEST['StateId'];
+$state = SimpleSAML_Auth_State::loadState($id, 'warning:expire');
+
+
+if (array_key_exists('proceed', $_REQUEST)) {
+ /* The user has pressed the proceed-button. */
+ SimpleSAML_Auth_ProcessingChain::resumeProcessing($state);
+}
+
+$globalConfig = SimpleSAML_Configuration::getInstance();
+
+$t = new SimpleSAML_XHTML_Template($globalConfig, 'authX509:X509warning.php');
+$t->data['target'] = SimpleSAML_Module::getModuleURL('authX509/expirywarning.php');
+$t->data['data'] = array('StateId' => $id);
+$t->data['daysleft'] = $state['daysleft'];
+$t->show();