Re: [PATCH v2 0/4] Checkpoint/Restore: Show in proc IDs of objects that can be shared between tasks

Tejun Heo
2011-11-18T23:46:43Z

Hello,

On Fri, Nov 18, 2011 at 05:10:37PM -0500, Kyle Moffett wrote:
> The #1 rule of one-time pads is never use it for more than one thing,
> and you use it here for every object in the system.

The new version is using different poison for different types of
objects.

> If you actually want to be able to compare uniqueness without exposing
> anything vulnerable to various kinds of guessing, you should generate
> a random 64-bit value for each class of object and then use a proper
> cryptographic hash function on it:
> crypto_hash(concat(object_ptr, random_value))
>
> Even given the best possible practical attacks against SHA1 or MD5
> today both still provides more than enough security to prevent someone
> from guessing "object_ptr" in less than an absurd amount of time.

So, per-type poison + crypto hash, it is then.

Thank you very much.

--
tejun