Backport of fixes from SA-CORE-2018-004. (#120)

* Backport of fixes from SA-CORE-2018-004.

* Update version to 6.44 and add changelog

CHANGELOG.txt

@@ -1,3 +1,7 @@
+Drupal 6.44 LTS, 2018-04-25
+---------------------------------------
+- Fixed security issues (remote code execution), backport. See SA-CORE-2018-004.
+
 Drupal 6.43 LTS, 2018-03-29
 -----------------------
 - Fixes bug from SA-CORE-2018-002 changes, update version.

includes/bootstrap.inc

@@ -1558,6 +1558,10 @@ function _drupal_bootstrap($phase) {
           unset($_GET['destination']);
           unset($_REQUEST['destination']);
         }
+        // Ensure that the destination's query parameters are not dangerous.
+        if (isset($_GET['destination'])) {
+          _drupal_bootstrap_clean_destination();
+        }
         // If there's still something in $_REQUEST['destination'] that didn't
         // come from $_GET, check it too.
         if (isset($_REQUEST['destination']) && (!isset($_GET['destination']) || $_REQUEST['destination'] != $_GET['destination']) && menu_path_is_external($_REQUEST['destination'])) {
@@ -2264,3 +2268,90 @@ function _drupal_bootstrap_sanitize_input(&$input, $whitelist = array()) {
 
   return $sanitized_keys;
 }
+
+/**
+ * Removes the destination if it is dangerous.
+ *
+ * Note this can only be called after common.inc has been included.
+ *
+ * @return bool
+ *   TRUE if the destination has been removed from $_GET, FALSE if not.
+ */
+function _drupal_bootstrap_clean_destination() {
+  $dangerous_keys = array();
+
+  $parts = _drupal_parse_url($_GET['destination']);
+  if (!empty($parts['query'])) {
+    $whitelist = variable_get('sanitize_input_whitelist', array());
+    $log_sanitized_keys = variable_get('sanitize_input_logging', FALSE);
+
+    $dangerous_keys = _drupal_bootstrap_sanitize_input($parts['query'], $whitelist);
+    if (!empty($dangerous_keys)) {
+      // The destination is removed rather than sanitized to mirror the
+      // handling of external destinations.
+      unset($_GET['destination']);
+      unset($_REQUEST['destination']);
+      if ($log_sanitized_keys) {
+        trigger_error(sprintf('Potentially unsafe destination removed from query string parameters (GET) because it contained the following keys: %s', implode(', ', $dangerous_keys)));
+      }
+      return TRUE;
+    }
+  }
+  return FALSE;
+}
+
+/**
+ * Backport of drupal_parse_url() from Drupal 7.
+ */
+function _drupal_parse_url($url) {
+  $options = array(
+    'path' => NULL,
+    'query' => array(),
+    'fragment' => '',
+  );
+
+  // External URLs: not using parse_url() here, so we do not have to rebuild
+  // the scheme, host, and path without having any use for it.
+  if (strpos($url, '://') !== FALSE) {
+
+    // Split off everything before the query string into 'path'.
+    $parts = explode('?', $url);
+    $options['path'] = $parts[0];
+
+    // If there is a query string, transform it into keyed query parameters.
+    if (isset($parts[1])) {
+      $query_parts = explode('#', $parts[1]);
+      parse_str($query_parts[0], $options['query']);
+
+      // Take over the fragment, if there is any.
+      if (isset($query_parts[1])) {
+        $options['fragment'] = $query_parts[1];
+      }
+    }
+  }
+  else {
+
+    // parse_url() does not support relative URLs, so make it absolute. E.g. the
+    // relative URL "foo/bar:1" isn't properly parsed.
+    $parts = parse_url('http://example.com/' . $url);
+
+    // Strip the leading slash that was just added.
+    $options['path'] = substr($parts['path'], 1);
+    if (isset($parts['query'])) {
+      parse_str($parts['query'], $options['query']);
+    }
+    if (isset($parts['fragment'])) {
+      $options['fragment'] = $parts['fragment'];
+    }
+  }
+
+  // The 'q' parameter contains the path of the current page if clean URLs are
+  // disabled. It overrides the 'path' of the URL when present, even if clean
+  // URLs are enabled, due to how Apache rewriting rules work. The path
+  // parameter must be a string.
+  if (isset($options['query']['q']) && is_string($options['query']['q'])) {
+    $options['path'] = $options['query']['q'];
+    unset($options['query']['q']);
+  }
+  return $options;
+}

modules/system/system.module

@@ -8,7 +8,7 @@
 /**
  * The current system version.
  */
-define('VERSION', '6.43');
+define('VERSION', '6.44');
 
 /**
  * Core API compatibility.