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.
