That is indeed the modern behaviour of chroot. It is not clear that the &quot;original implementation&quot; shown in the article shares that property, though.<p>EDIT: That&#x27;s not to say it <i>doesn&#x27;t</i> prevent that behaviour. If the usual code to prevent you ..ing above the root checks against u.u_rdir instead of &#x2F;, it might well work as modern implementations do.