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

[Kees Cook]

On Tue, Oct 2, 2012 at 2:41 PM, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxx> wrote:
> 2012/10/2 Kees Cook <keescook@xxxxxxxxxxxx>:
>>> If desired, additional restrictions can be imposed by using the
>>> security framework, e.g,, disallow non-final r-x mappings.
>>
>> Interesting; what kind of interface did you have in mind?
>
> The 'interface' we use is a LSM .ko which registers handlers for
> mmap() and mprotect() that fail the respective invocations if the
> passed arguments do not adhere to the policy.

Seems reasonable.

>>>> It seems like there needs to be a sensible way to detect that this flag is
>>>> available, though.
>>>
>>> I am open for suggestions to address this. Our particular
>>> implementation of the loader (on an embedded system) tries to set it
>>> on the first mmap invocation, and stops trying if it fails. Not the
>>> most elegant approach, I know ...
>>
>> Actually, that seems easiest.
>>
>> Has there been any more progress on this patch over-all?
>
> No progress.

Al, Andrew, anyone? Thoughts on this?
(First email is https://lkml.org/lkml/2012/8/14/448)

-Kees

-- 
Kees Cook
Chrome OS Security
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