[RFC PATCH v2 0/2] Randomization of address chosen by mmap.

[Matthew Wilcox]

On Tue, Mar 27, 2018 at 03:53:53PM -0700, Kees Cook wrote:
> I agree: pushing this off to libc leaves a lot of things unprotected.
> I think this should live in the kernel. The question I have is about
> making it maintainable/readable/etc.
> 
> The state-of-the-art for ASLR is moving to finer granularity (over
> just base-address offset), so I'd really like to see this supported in
> the kernel. We'll be getting there for other things in the future, and
> I'd like to have a working production example for researchers to
> study, etc.

One thing we need is to limit the fragmentation of this approach.
Even on 64-bit systems, we can easily get into a situation where there isn't
space to map a contiguous terabyte.