Date: Fri, 7 Nov 1997 10:55:19 +0100 (MET)
From: Christoph Kukulies <kuku@gilberto.physik.RWTH-Aachen.DE>
To: freebsd-hackers@freefall.FreeBSD.org
Subject: root - can root do an asm("cli")?
Message-ID: <199711070955.KAA27835@gil.physik.rwth-aachen.de>
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Is there a difference between what the kernel can do vs. what
a root process can do with regard to priviliged instructions?
In particular: can a root process do an asm("cli"); and thus
block the whole system? I tried once under FreeBSD
and got a bus error. May be the cause was a differnet one but
when I got that bus error I thought: "Hmm, fine, so there
is something running at a different ring which prevents root
from doing such malign things" and was feeling safe.
Now someone tells me, root can do everything and can even do
that.
--
Chris Christoph P. U. Kukulies kuku@gil.physik.rwth-aachen.de
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