linux-kernel - Re: [PATCH 1/2] tpm: Move tpm_get_random api into the TPM device driver

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Message-ID: <20120727145129.GB22046@linux.vnet.ibm.com>
Date:	Fri, 27 Jul 2012 09:51:29 -0500
From:	Kent Yoder <key@...ux.vnet.ibm.com>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	linux-kernel@...r.kernel.org, tpmdd-devel@...ts.sourceforge.net,
	m.selhorst@...rix.com, safford@...ibm.com
Subject: Re: [PATCH 1/2] tpm: Move tpm_get_random api into the TPM device
 driver

On Thu, Jul 26, 2012 at 05:10:44PM -0700, H. Peter Anvin wrote:
> On 06/07/2012 11:47 AM, Kent Yoder wrote:
> >Move the tpm_get_random api from the trusted keys code into the TPM
> >device driver itself so that other callers can make use of it. Also,
> >change the api slightly so that the number of bytes read is returned in
> >the call, since the TPM command can potentially return fewer bytes than
> >requested.
> >
> >Signed-off-by: Kent Yoder <key@...ux.vnet.ibm.com>
> 
> I see a second problem with this patch: you don't seem to handle the
> case where you get a short return anywhere in your code.  Presumably
> this should either be considered an error condition, or you need to
> create a private wrapper which can loop and make additional
> requests.
> 
> As it is if you get a short return you simply proceed as if you had
> gotten what you requested, since this was not an error mode
> supported by the old code.

Right, I did notice this but didn't think I was creating a regression
so I left it.  I'll add both a loop and then error out if that fails.

Thanks,
Kent

> 
> 	-hpa
> 
> -- 
> H. Peter Anvin, Intel Open Source Technology Center
> I work for Intel.  I don't speak on their behalf.
> 

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