Re: Updated: [PATCH] hardening: add PROT_FINAL prot flag to mmap/mprotect

[Kees Cook]

On Wed, Oct 3, 2012 at 7:43 AM, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxx> wrote:
> This patch adds support for the PROT_FINAL flag to
> the mmap() and mprotect() syscalls.
>
> The PROT_FINAL flag indicates that the requested set
> of protection bits should be final, i.e., it shall
> not be allowed for a subsequent mprotect call to
> set protection bits that were not set already.
>
> This is mainly intended for the dynamic linker,
> which sets up the address space on behalf of
> dynamic binaries. By using this flag, it can
> prevent exploited code from remapping read-only
> executable code or data sections read-write.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxx>

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

If it wasn't clear before, I like this idea. :)

-Kees

-- 
Kees Cook
Chrome OS Security
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