Re: [PATCH] User chroot

["H. Peter Anvin" <hpa@zytor.com>]

Followup to:  <20010627014534.B2654@ondska>
By author:    Jorgen Cederlof <jc@lysator.liu.se>
In newsgroup: linux.dev.kernel
> 
> Have you ever wondered why normal users are not allowed to chroot?
> 
> I have. The reasons I can figure out are:
> 
> * Changing root makes it trivial to trick suid/sgid binaries to do
>   nasty things.
> 
> * If root calls chroot and changes uid, he expects that the process
>   can not escape to the old root by calling chroot again.
> 
> If we only allow user chroots for processes that have never been
> chrooted before, and if the suid/sgid bits won't have any effect under
> the new root, it should be perfectly safe to allow any user to chroot.
> 

Safe, perhaps, but also completely useless: there is no way the user
can set up a functional environment inside the chroot.  In other
words, it's all pain, no gain.

	-hpa
-- 
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"Unix gives you enough rope to shoot yourself in the foot."
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