Re: [PATCH v3 2/2] tpm: in tpm2_del_space check if ops pointer is still valid

From: Greg KH <gregkh@linuxfoundation.org>
To: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Cc: peterhuewe@gmx.de, jarkko@kernel.org, jgg@ziepe.ca,
	stefanb@linux.vnet.ibm.com,
	James.Bottomley@hansenpartnership.com, stable@vger.kernel.org,
	linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
	Lino Sanfilippo <l.sanfilippo@kunbus.com>
Subject: Re: [PATCH v3 2/2] tpm: in tpm2_del_space check if ops pointer is still valid
Date: Fri, 5 Feb 2021 07:51:02 +0100	[thread overview]
Message-ID: <YBzq1trVOiBfxDVp@kroah.com> (raw)
In-Reply-To: <1612482643-11796-3-git-send-email-LinoSanfilippo@gmx.de>

On Fri, Feb 05, 2021 at 12:50:43AM +0100, Lino Sanfilippo wrote:
> From: Lino Sanfilippo <l.sanfilippo@kunbus.com>
> 
> In tpm2_del_space() chip->ops is used for flushing the sessions. However
> this function may be called after tpm_chip_unregister() which sets
> the chip->ops pointer to NULL.
> Avoid a possible NULL pointer dereference by checking if chip->ops is still
> valid before accessing it.
> 
> Fixes: a3fbfae82b4c ("tpm: take TPM chip power gating out of tpm_transmit()")
> Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
> ---
>  drivers/char/tpm/tpm2-space.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>