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SubjectRe: prevent breaking a chroot() jail?
Hi,

On 5 Jul 2002, Shaya Potter wrote:
> What should I be aware of? I figure devices (no need to run mknod in
> this jail) and chroot (as per man page), is there any other way of
> breaking the chroot jail (at a syscall level or otherwise)?
>
> or is this 100% impossible?

Well, since we're talking about root:

- If you had saved the old root before chroot()ing, use that one.
- If you have your whole disk exported via NFS, the prisoner process
could use nfs to read files outside the jail
- If you have access to a /dev directory, use /dev/sd?? to do the disc
access
- If not, use mknod("dideldei", 600, {68,1}); open("dideldei", O_SYNC);
and do as you like.

However, if you aren't running anything you find as root, it's relatively
secure.

Regards,
Thunder
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