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-rw-r--r--system/core/Common.php37
1 files changed, 37 insertions, 0 deletions
diff --git a/system/core/Common.php b/system/core/Common.php
index 6e2f72509..9dee591e6 100644
--- a/system/core/Common.php
+++ b/system/core/Common.php
@@ -479,6 +479,43 @@
$_error->log_exception($severity, $message, $filepath, $line);
}
+ // --------------------------------------------------------------------
+
+ /**
+ * Remove Invisible Characters
+ *
+ * This prevents sandwiching null characters
+ * between ascii characters, like Java\0script.
+ *
+ * @access public
+ * @param string
+ * @return string
+ */
+ function remove_invisible_characters($str)
+ {
+ static $non_displayables;
+
+ if ( ! isset($non_displayables))
+ {
+ // every control character except newline (dec 10), carriage return (dec 13), and horizontal tab (dec 09),
+ $non_displayables = array(
+ '/%0[0-8bcef]/', // url encoded 00-08, 11, 12, 14, 15
+ '/%1[0-9a-f]/', // url encoded 16-31
+ '/[\x00-\x08]/', // 00-08
+ '/\x0b/', '/\x0c/', // 11, 12
+ '/[\x0e-\x1f]/' // 14-31
+ );
+ }
+
+ do
+ {
+ $cleaned = $str;
+ $str = preg_replace($non_displayables, '', $str);
+ }
+ while ($cleaned != $str);
+
+ return $str;
+ }
/* End of file Common.php */