I want to turn on a part of the kernel to make SELinux checking more stringent.

[Andrew Lutomirski]

On Sun, Jan 26, 2014 at 12:38 PM, Richard W.M. Jones <rjones at redhat.com> wrote:
> Slightly OT, but is SELinux stopping programs from executing code at
> address zero?  (And how can I stop it doing that?)
>
> JONESFORTH, a public domain FORTH I wrote, is written in x86 assembler
> and prefers to put its threaded interpreter at address 0.  This worked
> fine before, but has now stopped working, and this is reported to be
> due to SELinux.

IIRC, in new kernels, /proc/sys/vm/mmap_min_addr and MAC policy both
have to allow the mmap call.  In older kernels, only one of them had
to allow it.

Maybe some day SMAP-capable machines (e.g. Haswell, I think) will
ignore these settings entirely -- I think that SMAP covers all the
cases that mmap_min_addr was meant to pretect against.

--Andy

>
> http://rwmj.wordpress.com/2010/08/07/jonesforth-git-repository/#comment-6591
>
>
> Rich.
>
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