On: The origins of chroot()

[xj9]

You don't. A correct `chroot()` implementation shouldn't let you access paths that aren't below the new `/`.

[qu4z-2 → xj9]

That is indeed the modern behaviour of chroot. It is not clear that the "original implementation" shown in the article shares that property, though.

EDIT: That's not to say it doesn't prevent that behaviour. If the usual code to prevent you ..ing above the root checks against u.u_rdir instead of /, it might well work as modern implementations do.

[smoyer → xj9]

My recollection of chroot in the late '90s is that it didn't provide a jail.

[tsotha → smoyer]

Must of been OS dependent. When I was doing bootp stuff in the mid '90s the whole point of chroot was the jail.