Re: [kernel-hardening] [PATCH 4/6] Protectable Memory

[Kees Cook]

On Sun, Feb 4, 2018 at 7:05 AM, Igor Stoppa <igor.stoppa@xxxxxxxxxx> wrote:
> On 04/02/18 00:29, Boris Lukashev wrote:
>> On Sat, Feb 3, 2018 at 3:32 PM, Igor Stoppa <igor.stoppa@xxxxxxxxxx> wrote:
>
> [...]
>
>>> What you are suggesting, if I have understood it correctly, is that,
>>> when the pool is protected, the addresses already given out, will become
>>> traps that get resolved through a lookup table that is built based on
>>> the content of each allocation.
>>>
>>> That seems to generate a lot of overhead, not to mention the fact that
>>> it might not play very well with the MMU.
>>
>> That is effectively what i'm suggesting - as a form of protection for
>> consumers against direct reads of data which may have been corrupted
>> by some irrelevant means. In the context of pmalloc, it would probably
>> be a separate type of ro+verified pool
> ok, that seems more like an extension though.
>
> ATM I am having problems gaining traction to get even the basic merged :-)
>
> I would consider this as a possibility for future work, unless it is
> said that it's necessary for pmalloc to be accepted ...

I would agree: let's get basic functionality in first. Both
verification and the physmap part can be done separately, IMO.

-Kees

-- 
Kees Cook
Pixel Security