On Thu, Aug 25, 2022 at 8:00 PM Jarkko Sakkinen <jarkko@xxxxxxxxxx> wrote: > > On Tue, Aug 23, 2022 at 03:25:17PM -0700, Evan Green wrote: > > From: Matthew Garrett <matthewgarrett@xxxxxxxxxx> > > > > Add an internal command for resetting a PCR. This will be used by the > > encrypted hibernation code to set PCR23 to a known value. The > > hibernation code will seal the hibernation key with a policy specifying > > PCR23 be set to this known value as a mechanism to ensure that the > > hibernation key is genuine. But to do this repeatedly, resetting the PCR > > is necessary as well. > > > > From: Matthew Garrett <mjg59@xxxxxxxxxx> > > This is probably here by mistake. > > > Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxx> > > > > No empty line here. > > > Signed-off-by: Evan Green <evgreen@xxxxxxxxxxxx> > > --- > > Matthew's original version of this patch was at: > > https://patchwork.kernel.org/patch/12096487/ > > > > (no changes since v1) > > > > drivers/char/tpm/tpm-interface.c | 28 +++++++++++++++++++++++++ > > drivers/char/tpm/tpm.h | 2 ++ > > drivers/char/tpm/tpm1-cmd.c | 34 ++++++++++++++++++++++++++++++ > > drivers/char/tpm/tpm2-cmd.c | 36 ++++++++++++++++++++++++++++++++ > > include/linux/tpm.h | 7 +++++++ > > 5 files changed, 107 insertions(+) > > > > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c > > index 1621ce8187052c..17b8643ee109c2 100644 > > --- a/drivers/char/tpm/tpm-interface.c > > +++ b/drivers/char/tpm/tpm-interface.c > > @@ -342,6 +342,34 @@ int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, > > } > > EXPORT_SYMBOL_GPL(tpm_pcr_extend); > > > > +/** > > + * tpm_pcr_reset - reset the specified PCR > > + * @chip: a &struct tpm_chip instance, %NULL for the default chip > > + * @pcr_idx: the PCR to be reset > > + * > > + * Return: same as with tpm_transmit_cmd() > > + */ > > +int tpm_pcr_reset(struct tpm_chip *chip, u32 pcr_idx) > > +{ > > + int rc; > > + > > + chip = tpm_find_get_ops(chip); > > + if (!chip) > > + return -ENODEV; > > + > > + if (chip->flags & TPM_CHIP_FLAG_TPM2) { > > + rc = tpm2_pcr_reset(chip, pcr_idx); > > + goto out; > > + } > > + > > + rc = tpm1_pcr_reset(chip, pcr_idx, "attempting to reset a PCR"); > > + > > +out: > > + tpm_put_ops(chip); > > if (chip->flags & TPM_CHIP_FLAG_TPM2) > rc = tpm2_pcr_reset(chip, pcr_idx); > else > rc = tpm1_pcr_reset(chip, pcr_idx, "attempting to reset a PCR"); > > Where does this asymmetry come with the parameters? Sorry for the delay, I was out last week. I think it's modeled to match the tpm1/2_pcr_extend functions, which have this same odd asymmetry. Should I change it to have both use the tpm2_pcr_reset() prototype? -Evan
