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SubjectRe: [RFC PATCH] Randomization of address chosen by mmap.
On Fri, Mar 02, 2018 at 11:30:28PM +0300, Ilya Smith wrote:
> This is a really good question. Lets think we choose address with random-length
> guard hole. This length is limited by some configuration as you described. For
> instance let it be 1MB. Now according to current implementation, we still may
> fill this gap with small allocations with size less than 1MB. Attacker will
> going to build attack base on this predictable behaviour - he jus need to spray
> with 1 MB chunks (or less, with some expectation). This attack harder but not
> impossible.

Ah, I didn't mean that. I was thinking that we can change the
implementation to reserve 1-N pages after the end of the mapping.
So you can't map anything else in there, and any load/store into that
region will segfault.

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