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SubjectRe: [PATCH] msr v3 available
Albert D. Cahalan writes:
>
> Richard Gooch writes:
>
> > Hi, all. Version 3 of my msr patch is now available from:
> ...
> > - Included patch which adds an ioctl() on /proc/<pid>/mem for
> > translating virtual to physical addresses
>
> As you've been told before, this is a security hole.

This has been asserted by a few. It has not yet been demonstrated
(either experimentally or theoretically) to be true. I've seen various
hypotheses float by, but all have proved bogus when considered. In the
end, all the security concerns are based on faith that exposing
physical pages must be "bad".

The same goes for denial of service attacks.

> Users have no business knowing what physical addresses are being
> used.

It's a powerful debugging tool. Even on a kernel with page colouring,
that doesn't mean you *get* page colouring. An application that is not
behaving as expected can start probing the foundations upon which it
resides.

> While many people are struggling to close information leaks and DoS
> attacks, you open more.

See above. So far every proposed "example" of security/DoS attacks
have been bogus.

> This gets very serious when Linux allows a limited number of
> locked pages for each normal user.

Nope. Think about it. These attacks are possible anyway.

Regards,

Richard....

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