From: Evan Green <evgreen@chromium.org>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Gwendal Grignou <gwendal@chromium.org>,
Eric Biggers <ebiggers@kernel.org>,
Matthew Garrett <mgarrett@aurora.tech>,
zohar@linux.ibm.com, linux-integrity@vger.kernel.org,
Pavel Machek <pavel@ucw.cz>,
apronin@chromium.org, Daniil Lunev <dlunev@google.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux PM <linux-pm@vger.kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
Matthew Garrett <matthewgarrett@google.com>,
Matthew Garrett <mjg59@google.com>, Hao Wu <hao.wu@rubrik.com>,
Jason Gunthorpe <jgg@ziepe.ca>, Peter Huewe <peterhuewe@gmx.de>,
axelj <axelj@axis.com>
Subject: Re: [PATCH v2 01/10] tpm: Add support for in-kernel resetting of PCRs
Date: Wed, 7 Sep 2022 10:02:14 -0700 [thread overview]
Message-ID: <CAE=gft6RuggyTSJXty5EskUcwLFEv4mrC1AL3HY-UgvXQRxvbA@mail.gmail.com> (raw)
In-Reply-To: <Ywg3JZrWmRjvr/7f@kernel.org>
On Thu, Aug 25, 2022 at 8:00 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> On Tue, Aug 23, 2022 at 03:25:17PM -0700, Evan Green wrote:
> > From: Matthew Garrett <matthewgarrett@google.com>
> >
> > 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@google.com>
>
> This is probably here by mistake.
>
> > Signed-off-by: Matthew Garrett <mjg59@google.com>
> >
>
> No empty line here.
>
> > Signed-off-by: Evan Green <evgreen@chromium.org>
> > ---
> > 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
next prev parent reply other threads:[~2022-09-07 17:02 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-23 22:25 [PATCH v2 00/10] Encrypted Hibernation Evan Green
2022-08-23 22:25 ` [PATCH v2 01/10] tpm: Add support for in-kernel resetting of PCRs Evan Green
2022-08-26 2:59 ` Jarkko Sakkinen
2022-09-07 17:02 ` Evan Green [this message]
2022-09-08 5:22 ` Jarkko Sakkinen
2022-08-23 22:25 ` [PATCH v2 02/10] tpm: Allow PCR 23 to be restricted to kernel-only use Evan Green
2022-08-26 3:02 ` Jarkko Sakkinen
2022-09-07 17:03 ` Evan Green
2022-09-13 12:26 ` Stefan Berger
2022-09-20 4:50 ` Jarkko Sakkinen
2022-09-21 15:35 ` Evan Green
2022-09-21 18:02 ` Jarkko Sakkinen
2022-09-21 18:05 ` Jarkko Sakkinen
2022-09-21 19:02 ` Evan Green
2022-08-23 22:25 ` [PATCH v2 03/10] security: keys: trusted: Include TPM2 creation data Evan Green
2022-09-20 23:04 ` Kees Cook
2022-09-23 22:22 ` Evan Green
2022-08-23 22:25 ` [PATCH v2 04/10] security: keys: trusted: Allow storage of PCR values in " Evan Green
2022-08-24 11:56 ` Ben Boeckel
2022-08-24 17:34 ` Evan Green
2022-08-23 22:25 ` [PATCH v2 05/10] security: keys: trusted: Verify " Evan Green
2022-09-20 23:06 ` Kees Cook
2022-09-23 22:23 ` Evan Green
2022-08-23 22:25 ` [PATCH v2 06/10] PM: hibernate: Add kernel-based encryption Evan Green
2022-09-20 23:09 ` Kees Cook
2022-08-23 22:25 ` [PATCH v2 07/10] PM: hibernate: Use TPM-backed keys to encrypt image Evan Green
2022-09-20 23:16 ` Kees Cook
2022-09-23 22:23 ` Evan Green
2022-09-24 4:31 ` Kees Cook
2022-08-23 22:25 ` [PATCH v2 08/10] PM: hibernate: Mix user key in encrypted hibernate Evan Green
2022-08-23 22:25 ` [PATCH v2 09/10] PM: hibernate: Verify the digest encryption key Evan Green
2022-08-23 22:25 ` [PATCH v2 10/10] PM: hibernate: seal the encryption key with a PCR policy Evan Green
2022-09-20 23:24 ` Kees Cook
2022-08-31 18:34 ` [PATCH v2 00/10] Encrypted Hibernation Limonciello, Mario
2022-09-07 17:03 ` Evan Green
2022-09-20 8:46 ` Pavel Machek
2022-09-20 16:39 ` Evan Green
2022-09-21 18:09 ` Jason Gunthorpe
2022-09-20 22:52 ` Kees Cook
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