Re: [PATCH] tpm_tis: verify locality released before returning from release_locality

[Laurent Bigonville]

Hello,

Top posting, sorry.

I don't know if I did it well to include the "Tested-by" tag because I 
don't see that the patch has landed in linus branch already.

And as far as I understand, this will not be in the upcoming 4.17 
release as we are already late in the cycle?

Kind regards,

Laurent Bigonville


Le 11/05/18 Ã 21:02, Laurent Bigonville a ÃcritÂ:
> Le 05/05/18 Ã 22:03, Jerry Snitselaar a ÃcritÂ:
> > On Sat May 05 18, Jerry Snitselaar wrote:
> > > For certain tpm chips releasing locality can take long enough that a
> > > subsequent call to request_locality will see the locality as being
> > > active when the access register is read in check_locality. So check
> > > that the locality has been released before returning from
> > > release_locality.
> > >
> > > Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > > Cc: Peter Huewe <peterhuewe@xxxxxx>
> > > Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> > > Reported-by: Laurent Bigonville <bigon@xxxxxxxxxx>
> > > Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
> Tested-by: Laurent Bigonville <bigon@xxxxxxxxxx>
> > > ---
> > > drivers/char/tpm/tpm_tis_core.c | 47 
> > > ++++++++++++++++++++++++++++++++++++++++-
> > > 1 file changed, 46 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/char/tpm/tpm_tis_core.c 
> > > b/drivers/char/tpm/tpm_tis_core.c
> > > index 5a1f47b43947..d547cd309dbd 100644
> > > --- a/drivers/char/tpm/tpm_tis_core.c
> > > +++ b/drivers/char/tpm/tpm_tis_core.c
> > > @@ -143,13 +143,58 @@ static bool check_locality(struct tpm_chip 
> > > *chip, int l)
> > > ÂÂÂÂreturn false;
> > > }
> > >
> > > +static bool locality_inactive(struct tpm_chip *chip, int l)
> > > +{
> > > +ÂÂÂ struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> > > +ÂÂÂ int rc;
> > > +ÂÂÂ u8 access;
> > > +
> > > +ÂÂÂ rc = tpm_tis_read8(priv, TPM_ACCESS(l), &access);
> > > +ÂÂÂ if (rc < 0)
> > > +ÂÂÂÂÂÂÂ return false;
> > > +
> > > +ÂÂÂ if ((access & (TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY))
> > > +ÂÂÂÂÂÂÂ == TPM_ACCESS_VALID)
> > > +ÂÂÂÂÂÂÂ return true;
> > > +
> > > +ÂÂÂ return false;
> > > +}
> > > +
> > > static int release_locality(struct tpm_chip *chip, int l)
> > > {
> > > ÂÂÂÂstruct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> > > +ÂÂÂ unsigned long stop, timeout;
> > > +ÂÂÂ long rc;
> > >
> > > ÂÂÂÂtpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);
> > >
> > > -ÂÂÂ return 0;
> > > +ÂÂÂ stop = jiffies + chip->timeout_a;
> > > +
> > > +ÂÂÂ if (chip->flags & TPM_CHIP_FLAG_IRQ) {
> > > +again:
> > > +ÂÂÂÂÂÂÂ timeout = stop - jiffies;
> > > +ÂÂÂÂÂÂÂ if ((long)timeout <= 0)
> > > +ÂÂÂÂÂÂÂÂÂÂÂ return -1;
> > > +
> > > +ÂÂÂÂÂÂÂ rc = wait_event_interruptible_timeout(priv->int_queue,
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ (locality_inactive(chip, l)),
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ timeout);
> > > +
> > > +ÂÂÂÂÂÂÂ if (rc > 0)
> > > +ÂÂÂÂÂÂÂÂÂÂÂ return 0;
> > > +
> > > +ÂÂÂÂÂÂÂ if (rc == -ERESTARTSYS && freezing(current)) {
> > > +ÂÂÂÂÂÂÂÂÂÂÂ clear_thread_flag(TIF_SIGPENDING);
> > > +ÂÂÂÂÂÂÂÂÂÂÂ goto again;
> > > +ÂÂÂÂÂÂÂ }
> > > +ÂÂÂ } else {
> > > +ÂÂÂÂÂÂÂ do {
> > > +ÂÂÂÂÂÂÂÂÂÂÂ if (locality_inactive(chip, l))
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ return 0;
> > > +ÂÂÂÂÂÂÂÂÂÂÂ tpm_msleep(TPM_TIMEOUT);
> > > +ÂÂÂÂÂÂÂ } while (time_before(jiffies, stop));
> > > +ÂÂÂ }
> > > +ÂÂÂ return -1;
> > > }
> > >
> > > static int request_locality(struct tpm_chip *chip, int l)
> > > --
> > > 2.15.0
> >
> > Laurent,
> >
> > Can you try this patch with your system since it is the one
> > that has exhibited the problem so far. I've tested on a
> > tpm2.0 and tpm1.2 system here.
> >
> > Regards,
> > Jerry