Re: + syscalls-x86-add-__nr_kcmp-syscall-v8.patch added to -mm tree

Valdis.Kletnieks
2012-04-11T00:04:05Z

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On Mon, 09 Apr 2012 16:22:38 -0700, "H. Peter Anvin" said:
> On 04/09/2012 03:24 PM, Cyrill Gorcunov wrote:
> >>
> >> Having re-read most of the (enormous) email discussion on the kcmp()
> >> syscall patch, I'm thinking:
> >>
> >> - Nobody seems to understand the obfuscation logic. Jon sounded
> >> confused, Oleg sounds confused and it's rather unclear what it does,
> >> how it does it and why it does it.
> >
> > The obfuscation logic was done with great help from hpa@. And the main
> > idea was to have ordered results after obfuscation. Per-type noise increase
> > randomization of results. So Andrew, I actually dont know what to add
> > here. We don't want to provide kernel order back to user-space in
> > naked manner.
> >
>
> The obfuscation logic is to provide a 1:1 mapping but which doesn't
> preserve ordering, thereby avoid leaking information of kernel pointers
> to user space.

Oh, OK... Ignore my previous note then. But we should lose the comment
that implies we have an ordering?

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