Re: Hurdish applications for persistence

[Bas Wijnen]

On Thu, Oct 13, 2005 at 11:49:49AM -0400, Jonathan S. Shapiro wrote:
> On Thu, 2005-10-13 at 11:48 +0200, Bas Wijnen wrote:
> > On Wed, Oct 12, 2005 at 09:21:24PM -0400, Jonathan S. Shapiro wrote:
> > > Umm, guys? Chroot() was a late bolt-on to UNIX that attempted to provide
> > > a best-effort approximation to confinement in a system where it was way
> > > too late to do the real thing.
> > > 
> > > There may be a good reason to copy a known bad quick patch when we now
> > > have a better solution, but could somebody explain it to me?
> > 
> > Because we want POSIX, of course.  However, in this case I would suggest a
> > different solution: Provide chroot, but let it fail unless an environment
> > variable or something is set...
> 
> Please let us know what you think of the Korn/Gansner approach as an
> alternative. I think it's cleaner.

It would definitely be cleaner, but I think it doesn't solve all problems.
Even when we solve the passive translator problem (say, by dropping them and
making a persistant system), there are still active translators.

If the chrooted filesystem contains an active translator, it will (correctly)
have a different root.  This can be used to construct communication channels,
but I feel it would also generate accidental channels.

Of course there is no danger of a chrooted task abusing it, as active
translators started by it will be chrooted as well.

I'm not sure if this really would become a problem, it's just intuition.

Anyway, a chroot with the Korn/Gansner approach sounds much better than what I
suggested, I'm just not sure if we shouldn't still recommend to not use it
(which is a sentence with far too many negations, sorry about that).

Thanks,
Bas

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