Re: [PATCH v2] tpm: Add check for Failure mode for TPM2 modules

[Marten Lindahl <martenli@axis.com>]

On Sun, Jun 26, 2022 at 08:21:03AM +0200, Jarkko Sakkinen wrote:
> On Mon, Jun 20, 2022 at 05:21:29PM +0200, Mårten Lindahl wrote:
> > In commit 0aa698787aa2 ("tpm: Add Upgrade/Reduced mode support for
> > TPM2 modules") it was said that:
> > 
> > "If the TPM is in Failure mode, it will successfully respond to both
> > tpm2_do_selftest() and tpm2_startup() calls. Although, will fail to
> > answer to tpm2_get_cc_attrs_tbl(). Use this fact to conclude that TPM
> > is in Failure mode."
> > 
> > But a check was never added in the commit when calling
> > tpm2_get_cc_attrs_tbl() to conclude that the TPM is in Failure mode.
> > This commit corrects this by adding a check.
> > 
> > Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
> > ---
> > 
> > v2:
> >  - Add missed check for TPM error code.
> > 
> >  drivers/char/tpm/tpm2-cmd.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> > index c1eb5d223839..65d03867e114 100644
> > --- a/drivers/char/tpm/tpm2-cmd.c
> > +++ b/drivers/char/tpm/tpm2-cmd.c
> > @@ -752,6 +752,12 @@ int tpm2_auto_startup(struct tpm_chip *chip)
> >  	}
> >  
> >  	rc = tpm2_get_cc_attrs_tbl(chip);
> > +	if (rc == TPM2_RC_FAILURE || (rc < 0 && rc != -ENOMEM)) {
> > +		dev_info(&chip->dev,
> > +			 "TPM in field failure mode, requires firmware upgrade\n");
> > +		chip->flags |= TPM_CHIP_FLAG_FIRMWARE_UPGRADE;
> > +		rc = 0;
> > +	}
> >  
> >  out:
> >  	/*
> > -- 
> > 2.30.2
> >

Hi Jarkko!

Yes, I will add the tags. Thanks!

Kind regards
Mårten
> 
> 
> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
> 
> Shouldn't this have:
> 
> Cc: stable@vger.kernel.org # v5.17
> Fixes: 0aa698787aa2 ("tpm: Add Upgrade/Reduced mode support for TPM2 modules")
> 
> BR, Jarkko