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 08:28:30PM +0530, Nayna wrote:
> 
> 
> On 11/16/2016 07:26 PM, 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.
> 
> Thanks Stefan !! I think it would be good to also add Fixes in commit
> description here.
> 
> Fixes: d660a91a1b9d (tpm: adds NULL check for securityfs pseudo files)

Not mandatory as this is not in the mainline tree but doesn't hurt
either.

/Jarkko

> 
> Thanks & Regards,
>   - Nayna
> 
> > 
> > Signed-off-by: Stefan Berger <stefanb-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@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]);
> > +		}
> >   	}
> >   }
> > 
> 

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