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

[Ard Biesheuvel]

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.

>>> 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.

-- 
Ard.
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