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

[Stefan Mahnke-Hartmann <stefan.mahnke-hartmann@infineon.com>]

> 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!
>
> Thank you. Yes it should have a fixes tag for the mentioned commit.
>
> Kind regards
> Mårten
>
> > 
> > BR, Jarkko

Hi Mårten,

your patch introduces redundant code. The code block of the if below
contains exactly the same code.

Additionally, your patch masks a bug (derefencing uninitialized
memory). I will send a patch set shortly.

Regards
Stefan