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Date: Mon, 22 Dec 2014 21:03:26 +0100 (CET)
From: Jiri Kosina <jkosina@suse.cz>
To: Andy Lutomirski <luto@amacapital.net>
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Subject: Re: [PATCH] ASLRv3: randomize_va_space=3 preventing offset2lib
 attack
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On Mon, 22 Dec 2014, Andy Lutomirski wrote:

> It could be worth having a mode that goes all out: randomize every
> single allocation independently in, say, a 45 or 46-byte range.  That
> would be about as strong ASLR as we could possibly have, it would
> result in guard intervals around mmap data allocations (which has real
> value), and it would still leave plenty of space for big address space
> hogs like the Chromium sandbox.
> 
> The main downside would be lots of memory used for page tables.

Plus get_random_int() during every mmap() call. Plus the resulting VA 
space fragmentation.

-- 
Jiri Kosina
SUSE Labs