1 files changed, 23 insertions, 0 deletions
diff --git a/api.php b/api.php
index fa85573d..ce445ef4 100644
--- a/api.php
+++ b/api.php
@@ -37,6 +37,29 @@ require (dirname(__FILE__) . '/includes/WebStart.php');
 
 wfProfileIn('api.php');
 
+// URL safety checks
+//
+// See RawPage.php for details; summary is that MSIE can override the
+// Content-Type if it sees a recognized extension on the URL, such as
+// might be appended via PATH_INFO after 'api.php'.
+//
+// Some data formats can end up containing unfiltered user-provided data
+// which will end up triggering HTML detection and execution, hence
+// XSS injection and all that entails.
+//
+// Ensure that all access is through the canonical entry point...
+//
+if( isset( $_SERVER['SCRIPT_URL'] ) ) {
+	$url = $_SERVER['SCRIPT_URL'];
+} else {
+	$url = $_SERVER['PHP_SELF'];
+}
+if( strcmp( "$wgScriptPath/api$wgScriptExtension", $url ) ) {
+	wfHttpError( 403, 'Forbidden',
+		'API must be accessed through the primary script entry point.' );
+	return;
+}
+
 // Verify that the API has not been disabled
 if (!$wgEnableAPI) {
 	echo 'MediaWiki API is not enabled for this site. Add the following line to your LocalSettings.php';