chroot()

[mash at whuxlb.UUCP]

chroot() must be protected lest programs that trust the sanctity of
certain files (/like /etc/passwd) be faked out by dummies:
1) create a small directory structure with a dummy /etc/passwd
2) make a copy of /bin/su & /bin/sh where they can be gotten.
3) chroot
4) su, then make the copy of sh setuid-root for later use.
[sad tosay, many systems have readable setuid-root pgms lying around].
-mashey