Re: [PATCH 3/7] SLIM main patch

From: Serge E. Hallyn
Date: Thu Aug 24 2006 - 15:13:38 EST


Quoting David Safford (safford@xxxxxxxxxxxxxx):
> On Thu, 2006-08-24 at 18:05 +0100, Alan Cox wrote:
> > It is a matter of the timing and the device. You need to do revocation
> > at the device level because your security state change must occur after
> > the devices have all been dealt with. This is why I said you need the
> > core of revoke() to do this.
>
> In a typical system, most applications are started at the correct level,
> and we don't have to demote/promote them. In those cases where demotion
> or promotion are needed, only a small number actually already have
> access that needs to be revoked. Of those, most involve shmem, which
> I believe we are revoking safely, as we don't have the same problems
> with drivers and incomplete I/O. In the remaining cases, where we really
> can't revoke safely, we could simply not allow the requested access, and
> not demote/promote the process.
>
> I think this would give us a useful balance of allowing "safe" demotion
> or promotions, while not requiring general revocation. Does this sound
> like a reasonable approach?

It sounds like you're saying "This should not be a problem unless the
system is being abused/exploited so let's not worry about it."

Assuming that wasn't your intent :), could you please rephrase?

thanks,
-serge


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