linux-kernel - Re: [PATCH 2/2] tpm: fix byte-order for the value read by tpm2_get_tpm

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Date:	Thu, 14 Jul 2016 20:17:01 -0700
From:	Andrey Pronin <apronin@...omium.org>
To:	Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Cc:	Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
	Peter Huewe <peterhuewe@....de>,
	Marcel Selhorst <tpmdd@...horst.net>,
	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	groeck@...omium.org, smbarber@...omium.org, dianders@...omium.org
Subject: Re: [PATCH 2/2] tpm: fix byte-order for the value read by
 tpm2_get_tpm_pt

On Thu, Jul 14, 2016 at 09:10:46PM -0600, Jason Gunthorpe wrote:
> On Thu, Jul 14, 2016 at 06:07:18PM -0700, Andrey Pronin wrote:
> > Change-Id: I7d71cd379b1a3b7659d20a1b6008216762596590
> > Signed-off-by: Andrey Pronin <apronin@...omium.org>
> >  drivers/char/tpm/tpm2-cmd.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> > index a1673dc..a88b31e 100644
> > +++ b/drivers/char/tpm/tpm2-cmd.c
> > @@ -703,7 +703,7 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
> >  
> >  	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), desc);
> >  	if (!rc)
> > -		*value = cmd.params.get_tpm_pt_out.value;
> > +		*value = be32_to_cpu(cmd.params.get_tpm_pt_out.value);
> 
> Huh.
> 
> Jarkko: Are you running sparse on the tpm stuff? The annotations look
> right here, sparse should have complained on this? Andrey, did sparse
> complain here or is there something more serious wrong as well??
> 
> Reviewed-by: Jason Gunthorpe <jgunthorpe@...idianresearch.com>
> 
> Jason

No, this is not sparse complaining. I tried using tpm2_get_tpm_pt() to
read permanent flags and discovered that it was missing byte-ordering
conversion. The only place tpm2_get_tpm_pt() was used before was in
tpm2_gen_interrupt, which discarded the result. So, nobody noticed,
I guess.

Andrey