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Subject: Re: [tpmdd-devel] [PATCH v2 1/2] tpm2: add session handle context
 saving and restoring to the space code
From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: linux-security-module@vger.kernel.org,
        tpmdd-devel@lists.sourceforge.net,
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Date: Mon, 30 Jan 2017 14:14:37 -0800
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On Mon, 2017-01-30 at 23:45 +0200, Jarkko Sakkinen wrote:
> On Sun, Jan 29, 2017 at 02:36:58PM -0800, James Bottomley wrote:
[...]
> > > 2. Can it really return both TPM_RC_HANDLE and
> > > TPM_RC_REFERENCE_H0? 
> > 
> > Yes, it seems that a session that doesn't exist (because it's been
> > flushed) then it returns TPM_RC_REFERNCE_H0, but if the context has 
> > a sequence mismatch (because it's been flushed and reloaded) then 
> > we get TPM_RC_HANDLE.
> > 
> > James
> 
> If it is flushed, wouldn't you just get TPM_RC_REFERENCE_H0 when you 
> try to TPM2_ContextLoad? The "and reloaded" does not make sense to 
> me. Once a session is flushed it cannot be reloaded.
> 
> Maybe you meant to say "beause it's been saved and reloaded"? That 
> would make more sense and fits better what I see in the Commands 
> specification.

I mean if you load a prior context instead of the current one for an
existing handle, effectively a replay, you get TPM_RC_HANDLE.

James