Messages in this thread | | | Subject | Re: [PATCH 1/4] integrity: TPM internel kernel interface | From | Kenneth Goldman <> | Date | Tue, 12 Aug 2008 16:57:31 -0400 |
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Christoph Hellwig <hch@infradead.org> wrote on 08/12/2008 03:30:31 PM:
> On Mon, Aug 11, 2008 at 05:13:51PM -0400, Mimi Zohar wrote: > > > > I assume the concern here is that between looking up the chip and actually > > > > using the chip, the TPM chip is disabled/deactivated. Based on > > discussions > > with Kenneth Goldman, the TCG main specification part2: structures, > > require > > that even if the TPM is disabled/deactivated, the command to extend the
> > PCR > > will succeed, but the command to read the PCR will fail with an > > appropriate > > error code. > > And what happens when the chip simply goes away due to a hotplug action? > Or not even the actual chip goes away but just the chip driver and you > now dereference freed memory?
Being a TCG/TPM person, I can only address the first question. The intent is that the TPM is soldered to the planar/motherboard (the TCG uses the phrase "bound to the platform"). I can't imagine any manufacturer designing a pluggable TPM. It would subvert PCR measurements and thus attestation, data sealing, etc.
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