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

[Jarkko Sakkinen <jarkko@kernel.org>]

On Wed, Jun 01, 2022 at 05:05:08AM +0300, Jarkko Sakkinen wrote:
> On Mon, 2022-05-30 at 17:26 +0200, Marten Lindahl wrote:
> > On Mon, Apr 25, 2022 at 05:52:04PM +0200, Mårten Lindahl wrote:
> > > On Mon, Apr 25, 2022 at 04:03:33PM +0200, Jarkko Sakkinen wrote:
> > > > On Mon, 2022-04-25 at 12:25 +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>
> > > > 
> > > > Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
> > > > 
> > > > I think this should actually have the fixes tag. It's a regression,
> > > > right? I can add it.
> > 
> > Hi Jarkko!
> > 
> > Just curious. I can't see this patch was added to linux-next. Was I
> > expected to do something more to it?
> 
> No it's just me failing to do my job properly. I'll pick this and
> make a 2nd pull request v5.19. Apologies.

I revisited the patch, and it does not look right to me.

If tpm2_get_cc_attrs_tbl() fails, there's no way to deduce
from that "fact" that the TPM response was TPM_RC_FAILURE.

BR, Jarkko