RE: Future Linux devel. Kernels

From: Simon Richter (
Date: Mon May 08 2000 - 08:22:53 EST

On Mon, 8 May 2000, Igmar Palsenberg wrote:

> BSDI also has a mode like this, the kernel secure levels. Basically means
> that some operations are disabled, and the only was to switch the level is
> from init 1 :-))

> The 'main' risk if someone gets in that he replaces system bins.. So the
> only way to detect this is a proper logging system, that cannot be
> modified without someone noticing.

This is something that can be handled with securelevels. Mark the system
binaries as immutable and the only way to change them is from singleuser.
However, iopl() still can be used to circumvent this, and as long as Linux
allows hardware access to user-level apps, you cannot make a system

> > > If the guy (girl) really know what he is doing he is able to wipe his
> > > traces..

Noone can escape a 9-dot printer on /dev/lp0.

> > Again: if /dev/kmem is readable on system :-)

> It is as root.. And it it is not as root, what's the use of /dev/kmem ?

Good question. What is its use? (Hint: I know how the accelerated X
servers work.)


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