From: Mimi Zohar <zohar@linux.ibm.com>
To: Jerry Snitselaar <jsnitsel@redhat.com>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: "Petr Vorel" <pvorel@suse.cz>, Nayna <nayna@linux.vnet.ibm.com>,
linux-integrity <linux-integrity@vger.kernel.org>,
ltp@lists.linux.it, "Piotr Król" <piotr.krol@3mdeb.com>,
"Peter Huewe" <peterhuewe@gmx.de>,
"Jason Gunthorpe" <jgg@ziepe.ca>
Subject: Re: [LTP] [PATCH] ima: skip verifying TPM 2.0 PCR values
Date: Thu, 24 Oct 2019 20:47:00 -0400 [thread overview]
Message-ID: <1571964420.5173.12.camel@linux.ibm.com> (raw)
In-Reply-To: <20191024213842.c6cl4tlnsi56pgcy@cantor>
On Thu, 2019-10-24 at 14:38 -0700, Jerry Snitselaar wrote:
> On Thu Oct 24 19, Jarkko Sakkinen wrote:
> >On Thu, Oct 24, 2019 at 02:18:48PM +0200, Petr Vorel wrote:
> >> Hi all,
> >>
> >> I wonder what to do with this patch "ima: skip verifying TPM 2.0 PCR values" [1].
> >> Is it a correct way to differentiate between TPM 1.2 and TPM 2.0?
> >> Or something else should be applied?
> >>
> >> How is the work on TPM 2.0 Linux sysfs interface?
> >> But even it's done in near future, we'd still need some way for older kernels.
> >>
> >> Kind regards,
> >> Petr
> >>
> >> [1] https://patchwork.ozlabs.org/patch/1100733/
> >
> >version_major sysfs file would be acceptable if someone wants to proceed
> >and send such patch.
> >
> >Also replicants for durations and timeouts files would make sense for
> >TPM 2.0.
> >
> >/Jarkko
>
> Is it as simple as doing this?
>
> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
> index edfa89160010..fd8eb8d8945c 100644
> --- a/drivers/char/tpm/tpm-sysfs.c
> +++ b/drivers/char/tpm/tpm-sysfs.c
> @@ -309,7 +309,17 @@ static ssize_t timeouts_show(struct device *dev, struct device_attribute *attr,
> }
> static DEVICE_ATTR_RO(timeouts);
>
> -static struct attribute *tpm_dev_attrs[] = {
> +static ssize_t version_major_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct tpm_chip *chip = to_tpm_chip(dev);
> +
> + return sprintf(buf, "TPM%s\n", chip->flags & TPM_CHIP_FLAG_TPM2
> + ? "2.0" : "1.2");
> +}
> +static DEVICE_ATTR_RO(version_major);
> +
> +static struct attribute *tpm12_dev_attrs[] = {
> &dev_attr_pubek.attr,
> &dev_attr_pcrs.attr,
> &dev_attr_enabled.attr,
> @@ -320,18 +330,28 @@ static struct attribute *tpm_dev_attrs[] = {
> &dev_attr_cancel.attr,
> &dev_attr_durations.attr,
> &dev_attr_timeouts.attr,
> + &dev_attr_version_major.attr,
> NULL,
> };
>
The TPM version seems to be included in "dev_attr_caps.attr".
> -static const struct attribute_group tpm_dev_group = {
> - .attrs = tpm_dev_attrs,
> +static struct attribute *tpm20_dev_attrs[] = {
> + &dev_attr_version_major.attr,
> + NULL
> +};
This should work, but wouldn't exporting this information under
security/tpmX, like the binary_bios_measurements, be a lot easier to
find and use?
Mimi
> +
> +static const struct attribute_group tpm12_dev_group = {
> + .attrs = tpm12_dev_attrs,
> +};
> +
> +static const struct attribute_group tpm20_dev_group = {
> + .attrs = tpm20_dev_attrs,
> };
>
> void tpm_sysfs_add_device(struct tpm_chip *chip)
> {
> - if (chip->flags & TPM_CHIP_FLAG_TPM2)
> - return;
> -
> WARN_ON(chip->groups_cnt != 0);
> - chip->groups[chip->groups_cnt++] = &tpm_dev_group;
> + if (chip->flags & TPM_CHIP_FLAG_TPM2)
> + chip->groups[chip->groups_cnt++] = &tpm20_dev_group;
> + else
> + chip->groups[chip->groups_cnt++] = &tpm12_dev_group;
> }
>
>
> Did a quick test on 2 systems here.
next prev parent reply other threads:[~2019-10-25 0:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-16 21:12 [PATCH] ima: skip verifying TPM 2.0 PCR values Mimi Zohar
2019-05-17 6:51 ` Petr Vorel
2019-05-17 11:19 ` Mimi Zohar
2019-05-17 11:28 ` Petr Vorel
2019-05-17 13:50 ` Nayna
2019-05-17 15:04 ` Petr Vorel
2019-10-24 12:18 ` [LTP] " Petr Vorel
2019-10-24 17:20 ` Jarkko Sakkinen
2019-10-24 18:20 ` Jason Gunthorpe
2019-10-24 19:14 ` Jarkko Sakkinen
2019-10-24 23:36 ` Jason Gunthorpe
2019-10-28 20:51 ` Jarkko Sakkinen
2019-10-24 21:38 ` Jerry Snitselaar
2019-10-24 23:26 ` Jason Gunthorpe
2019-10-25 0:47 ` Mimi Zohar [this message]
2019-10-25 2:11 ` Jerry Snitselaar
2019-10-25 8:56 ` Petr Vorel
2019-10-25 12:52 ` Serge E. Hallyn
2019-10-25 13:22 ` Mimi Zohar
2019-10-25 13:25 ` Petr Vorel
2019-10-25 14:13 ` Jerry Snitselaar
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