Re: [RFC PATCH] Randomization of address chosen by mmap.

[Ilya Smith]

> On 2 Mar 2018, at 23:48, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> 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.
> 

Iâm afraid it still will allow many attacks. The formula for new address would 
be like: address_next = address_prev - mmap_size - random(N) as you suggested. 
To prevent brute-force attacks N should be big enough  like more 2^32 for 
example. This number 2^32 is just an example and right now I donât know the 
exact value. What Iâm trying to say that address computation formula has 
dependency on concrete predictable address. In my scheme even address_prev was 
chose randomly. 

Best regards,
Ilya