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

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Message-ID: <5011DC84.6010003@zytor.com>
Date:	Thu, 26 Jul 2012 17:10:44 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Kent Yoder <key@...ux.vnet.ibm.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 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.

	-hpa

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

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