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SubjectRe: ext3 to include capabilities?
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Matthew Kirkwood <weejock@ferret.lmh.ox.ac.uk> said:
> On Thu, 1 Apr 1999, Albert D. Cahalan wrote:

[...]

> > The kernel would ignore your header if the executable is not marked
> > setuid root. If you can mark the executable setuid root, then you have
> > already cracked root anyway -- why not "emacs /etc/passwd" instead?

> Your suggestion relies upon additional code in the dynamic loader (in fact
> in every dynamic loader - a.out, ELF, Java). If I convince my admin that
> I need raw socket privs for a perl script, should he really giveme an suid
> perl binary? Not if me expects me to stay there.

Why not? You'd get a perl binary that has the capability you asked for,
nothing more.

> Your ideas put security detection (OK, so "SD" here is a meaningless
> phrase), and enforcement into the kernel.

Can't be done anywhere else: It has to be done by a trusted authority, and
the ultimate trusted authority is (and always will be) the kernel and the
underlying hardware.

> The kernel currently doesn't attempt to regulate the things which various
> processes run. It shouldn't. The current abstractions make that
> unnecessary. Yes, they also make kernel mods a periodic requirement but I
> find the kernel source __much, much less painful__ than glibc. Your ideas
> also require the kernel to restrict the activities of user specified
> dynamic loaders/interpreters...

In a sense, those are kernel extensions. You'd have to trust them too, for
otherwise they could just mangle the executable in interesting ways
(loading "wrong" libraries, ...).
--
Horst von Brand vonbrand@sleipnir.valparaiso.cl
Casilla 9G, Viña del Mar, Chile +56 32 672616

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