PHP 5.4SVN-2012-02-03 - htmlspecialchars/entities Buffer Overflow

From:             cataphract
Operating system: Any
PHP version:      5.4SVN-2012-02-03 (SVN)
Package:          Reproducible crash
Bug Type:         Bug
Bug description:Buffer overflow on htmlspecialchars/entities with $double=false

Description:
------------
Long entities can cause a buffer overflow because the loop only guarantees
40 bytes available in beginning.

Test script:
---------------
<?php
echo
htmlspecialchars('"""""""""""""""""""""""""""""""""""""""""""""&#x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000005;',
ENT_QUOTES, 'UTF-8', false), "\n";