Aw: Re: [PATCH] tpm: fix potential NULL pointer access in tpm_del_char_device()

[Lino Sanfilippo <LinoSanfilippo@gmx.de>]

Hi,

> Gesendet: Montag, 13. September 2021 um 22:25 Uhr
> Von: "Jarkko Sakkinen" <jarkko@kernel.org>
> An: "Lino Sanfilippo" <LinoSanfilippo@gmx.de>, peterhuewe@gmx.de, jgg@ziepe.ca
> Cc: p.rosenberger@kunbus.com, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org
> Betreff: Re: [PATCH] tpm: fix potential NULL pointer access in tpm_del_char_device()
>
> On Fri, 2021-09-10 at 20:04 +0200, Lino Sanfilippo wrote:
> > In tpm_del_char_device() make sure that chip->ops is still valid.
> > This check is needed since in case of a system shutdown
> > tpm_class_shutdown() has already been called and set chip->ops to NULL.
> > This leads to a NULL pointer access as soon as tpm_del_char_device()
> > tries to access chip->ops in case of TPM 2.
> >
> > Fixes: dcbeab1946454 ("tpm: fix crash in tpm_tis deinitialization")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
> > ---
>
> Have you been able to reproduce this in some environment?
>
> /Jarkko
>
>

Yes, this bug is reproducable on my system that is running a 5.10 raspberry kernel.
I use a SLB 9670 which is connected via SPI.

Regards,
Lino