Messages in this thread | | | From | "H. Peter Anvin" <> | Subject | Re: prevent breaking a chroot() jail? | Date | 5 Jul 2002 11:15:39 -0700 |
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Followup to: <1025877004.11004.59.camel@zaphod> By author: Shaya Potter <spotter@cs.columbia.edu> In newsgroup: linux.dev.kernel > > I'm trying to develop a way to ensure that one can't break out of a > chroot() jail, even as root. I'm willing to change the way the syscalls > work (most likely only for a subset of processes, i.e. processes that > are run in the jail end up getting a marker which is passed down to all > their children that causes the syscalls to behave differently). > > 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? >
This sounds like a job for [dum de dum dum] capabilities... remember, on Linux root hasn't been almighty for a very long time, it's just a matter of which capabilities you retain. Of course, if you really want to be safe, you might end up with a rather castrated root inside the chroot shell.
If you really want to jail something, use UML.
-hpa -- <hpa@transmeta.com> at work, <hpa@zytor.com> in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt <amsp@zytor.com> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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