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From:   Lino Sanfilippo <LinoSanfilippo@gmx.de>
To:     Jarkko Sakkinen <jarkko@kernel.org>
Cc:     peterhuewe@gmx.de, jgg@ziepe.ca, p.rosenberger@kunbus.com,
        linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Subject: Aw: Re: [PATCH] tpm: fix potential NULL pointer access in
 tpm_del_char_device()
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Date:   Mon, 13 Sep 2021 22:53:50 +0200
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References: <20210910180451.19314-1-LinoSanfilippo@gmx.de>
 <204a438b6db54060d03689389d6663b0d4ca815d.camel@kernel.org>
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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@zi=
epe.ca
> Cc: p.rosenberger@kunbus.com, linux-integrity@vger.kernel.org, linux-ker=
nel@vger.kernel.org, stable@vger.kernel.org
> Betreff: Re: [PATCH] tpm: fix potential NULL pointer access in tpm_del_c=
har_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 raspberr=
y kernel.
I use a SLB 9670 which is connected via SPI.

Regards,
Lino