Re: The disappearing sys_call_table export.

Richard B. Johnson
2003-05-14T21:17:03Z

On Wed, 14 May 2003, Mike Touloumtzis wrote:

> On Wed, May 14, 2003 at 06:34:30AM -0400, Ahmed Masud wrote:
> >
> > Level of security is a matter of trust. Should the kernel trust a
> > distribution provider? No, that is not a reasonable request, because we do
> > not control their environment and evaluation proceedures and there are no
> > guarentees between the channel that provides the operating system to the
> > time it gets installed on a system.
>
> I don't understand why people are willing to base security arguments
> on some sort of bizarre adversarial relationship between the kernel and
> the system tools.
>
> No Unix (even a "secure" one) is designed to run all security-critical
> code in the kernel. That would be a bad design anyway, since it would
> run lots of code at an unwarranted privilege level. "login" is not
> part of the kernel. "su" is not part of the kernel". The boot loader
> is not part of the kernel. And so on.
>
> There is no issue of "trust" between the kernel and the distribution
> provider. The distribution provider provides a system, which (like all
> Unix-derived systems) is modular and thus has multiple independent
> components with security functions. The sum of those parts is what you
> should evaluate for security. Yes, the system should include proper
> isolation mechanisms to prevent improper privilege escalations. But it
> doesn't make sense to even think about what the kernel should do when
> the untrusted distribution provides a malicious "/sbin/init".

Not even malicious. For years, it was accepted that if you had
physical possesion of a computing system, you could do anything
with it that it was capable of.

Not so, with the latest Red Hat distribution (9). You can no longer
set init=/bin/bash at the boot prompt.... well you can set it, but
then you get an error about killing init. This caused a neighbor
a lot of trouble when she accidentally put a blank line in the
top of /etc/passwd. Nobody could log-in. I promised to show her
how to "break in", but I wasn't able to. I had to take her hard-disk
to my house, mount it, and fix the password file. All these "attempts"
at so-called security do is make customers pissed.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.20 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.