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From: kgold@linux.vnet.ibm.com (Ken Goldman)
To: linux-security-module@vger.kernel.org
Subject: about context gap
Date: Tue, 26 Sep 2017 14:46:59 -0400	[thread overview]
Message-ID: <03018f5e-4afc-7db5-b5a8-dfed8e2bd8d2@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170918180250.6db5ti4gpinqr5jz@linux.intel.com>

On 9/18/2017 2:02 PM, Jarkko Sakkinen wrote:

> Other than context gap it would probably make sense to estimate TPM
> capacity in order to make implementation more intelligent. We could
> measure memory capacity of a TPM in the driver initialization by filling
> it with fixed size dummy objects.
> 
> TPM2_GetCapability gives stuff that cannot be really trusted as spec
> compliant TPM HW could just return always '1' for max.

I don't see anything in the TPM specs that claim the TPM can return 1.

E.g., the PC Client spec says that loaded sessions must return a minimum 
of 3.  Active sessions must return a minimum of 64.

I think the resource manager can safely use these getcapability values.

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  reply	other threads:[~2017-09-26 18:46 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-16 15:36 about context gap Jarkko Sakkinen
2017-09-18 18:02 ` Jarkko Sakkinen
2017-09-26 18:46   ` Ken Goldman [this message]
2017-09-26 19:10 ` Ken Goldman

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