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    SubjectRe: The disappearing sys_call_table export.
    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.

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