Subject: Re: new kpi proposal, sysdisk(9)
To: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
From: Bill Studenmund <wrstuden@netbsd.org>
List: tech-kern
Date: 01/10/2007 09:32:53
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On Wed, Jan 10, 2007 at 12:27:45PM +0900, YAMAMOTO Takashi wrote:
> > YAMAMOTO Takashi wrote:
> > > i don't understand the comment.  can you explain?
> >=20
> > sure. let's say you run a system with veriexec strict level 1. it won't
> > deny raw disk access, even to mounts it monitors, so you can just open
> > the disk for read/write. then, when strict level is raised, we
> > supposedly have to block raw disk access, but an attacker might already
> > have a descriptor.
> >=20
> > so what I suggested is to keep track of "number of raw disk users" and
> > just make veriexec not cache the evaluation result if this number is
> > > 0.
>=20
> assuming you want to have it in spec_open/close,
> where to store diskuser_t * can be a problem.

Couldn't we store it in struct disk? We then have the device specific open=
=20
and close routines call a common wrapper that handles the count issues.

Take care,

Bill

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