Re: [PATCH v6 0/7] Kernel base address randomization

From: H. Peter Anvin
Date: Wed Oct 02 2013 - 01:32:13 EST


On 10/01/2013 10:25 PM, Ingo Molnar wrote:
>
> I mean, for example in an oops message we print data in words: the RIP,
> other registers and stack contents. If any of these values lies within the
> randomization range then we could de-randomize it.
>
> So instead of exposing randomized values, we could expose de-randomized
> values.
>
> ( This isn't fool-proof: if some data value happens to lie within the
> random range spuriously then we'll incorrectly transform it. In the
> context of oops messages this should not be a big practical problem
> though. )
>

I don't agree that this isn't a big practical problem. I often find it
necessary to pick out "things that look like pointers". Overall,
derandomization would make it possible to get really confused when you
have things like half a pointer overwritten.

-hpa


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