Re: is avoiding compat ioctls possible?

[Andi Kleen]

On Tue, Oct 27, 2009 at 08:45:30PM -0700, David Miller wrote:
> From: Dave Airlie <airlied@xxxxxxxx>
> Date: Wed, 28 Oct 2009 03:43:07 +0000 (GMT)
> 
> > we already opencoded this (probably before it was macroisied or we just 
> > pasted it), so the radeon one is buggy, I should just go and compat_* all 
> > of these then and we should be all happy?
> 
> It should be, it's only working because:
> 
> 1) A malicious userland hasn't put garbage in the upper bits for
>    you yet.

The x86 compat_ptr wouldn't even help with that because it doesn't mask.

If they use *_user() or anything else with access_ok later that should
be caught properly. The user land could only put in pointers to unmapped 
[32bit...kernel boundary] data, which is harmless.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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