Re: [PATCH] tpm: Check the bios_dir entry for NULL before accessing it

[Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

On Wed, Nov 16, 2016 at 08:56:13AM -0500, Stefan Berger wrote:
> Check the bios_dir entry for NULL before accessing it. Currently
> this crashes the driver when a TPM 2 is attached and the entries
> are NULL.
> 
> Signed-off-by: Stefan Berger <stefanb-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>

> ---
>  drivers/char/tpm/tpm_eventlog.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_eventlog.c b/drivers/char/tpm/tpm_eventlog.c
> index ebec4ac..fb603a7 100644
> --- a/drivers/char/tpm/tpm_eventlog.c
> +++ b/drivers/char/tpm/tpm_eventlog.c
> @@ -455,10 +455,12 @@ void tpm_bios_log_teardown(struct tpm_chip *chip)
>  	 * This design ensures that open() either safely gets kref or fails.
>  	 */
>  	for (i = (TPM_NUM_EVENT_LOG_FILES - 1); i >= 0; i--) {
> -		inode = d_inode(chip->bios_dir[i]);
> -		inode_lock(inode);
> -		inode->i_private = NULL;
> -		inode_unlock(inode);
> -		securityfs_remove(chip->bios_dir[i]);
> +		if (chip->bios_dir[i]) {
> +			inode = d_inode(chip->bios_dir[i]);
> +			inode_lock(inode);
> +			inode->i_private = NULL;
> +			inode_unlock(inode);
> +			securityfs_remove(chip->bios_dir[i]);
> +		}
>  	}
>  }
> -- 
> 2.4.3

/Jarkko

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