fix segfault when invalid field offset is passed to mysqli_fetch_field_direct()

diff --git a/ext/mysqli/mysqli_api.c b/ext/mysqli/mysqli_api.c
index b80beba4d4a6e04bb5b221909301bcb5c306b26b..f403105a928348bf90edbe13924a68f2cc343332 100644 (file)
--- a/ext/mysqli/mysqli_api.c
+++ b/ext/mysqli/mysqli_api.c
@@ -753,6 +753,11 @@ PHP_FUNCTION(mysqli_fetch_field_direct)
 
        MYSQLI_FETCH_RESOURCE(result, MYSQL_RES *, &mysql_result, "mysqli_result"); 
 
+       if (offset < 0 || offset >= mysql_num_fields(result)) {
+               php_error_docref(NULL TSRMLS_CC, E_WARNING, "Field offset is invalid for resultset");
+               RETURN_FALSE; 
+       }
+
        if (!(field = mysql_fetch_field_direct(result,offset))) {
                RETURN_FALSE;
        }