Sanitize a query comment string.

Ensure a query comment does not include strings such as "* /" that might terminate the comment early. This avoids SQL injection attacks via the query comment. The comment strings in this example are separated by a space to avoid PHP parse errors.

For example, the comment:

db_update('example')
 ->condition('id', $id)
 ->fields(array('field2' => 10))
 ->comment('Exploit * / DROP TABLE node; --')
 ->execute()

Would result in the following SQL statement being generated:

"/ * Exploit * / DROP TABLE node; -- * / UPDATE example SET field2=..."

Unless the comment is sanitised first, the SQL server would drop the node table and ignore the rest of the SQL statement.

Parameters

$comment: A query comment string.

Return value

A sanitized version of the query comment string.

File

drupal-7.x/includes/database/database.inc, line 626

Core systems for the database layer.

Class

DatabaseConnection

Base Database API class.

Code

protected function filterComment($comment = '') {
  return preg_replace('/(\/\*\s*)|(\s*\*\/)/', '', $comment);
}