[PATCH] tpm: Add major_version sysfs file

[PATCH] tpm: Add major_version sysfs file

[Jerry Snitselaar]

Easily determining what TCG version a tpm device implements
has been a pain point for userspace for a long time, so
add a sysfs file to report the tcg version of a tpm device.

Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Peter Huewe <peterhuewe@gmx.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-integrity@vger.kernel.org
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
---
 drivers/char/tpm/tpm-sysfs.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index edfa89160010..9372c2d6f0b3 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 major_version_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct tpm_chip *chip = to_tpm_chip(dev);
+
+	return sprintf(buf, "%s\n", chip->flags & TPM_CHIP_FLAG_TPM2
+		       ? "2.0" : "1.2");
+}
+static DEVICE_ATTR_RO(major_version);
+
+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_major_version.attr,
 	NULL,
 };
 
-static const struct attribute_group tpm_dev_group = {
-	.attrs = tpm_dev_attrs,
+static struct attribute *tpm20_dev_attrs[] = {
+	&dev_attr_major_version.attr,
+	NULL
+};
+
+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;
 }
-- 
2.23.0

Re: [PATCH] tpm: Add major_version sysfs file

[Mimi Zohar]

On Fri, 2019-10-25 at 07:28 -0700, Jerry Snitselaar wrote:
> Easily determining what TCG version a tpm device implements
> has been a pain point for userspace for a long time, so
> add a sysfs file to report the tcg version of a tpm device.

Use "TCG" uppercase consistently.
 
> 
> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Cc: Peter Huewe <peterhuewe@gmx.de>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: linux-integrity@vger.kernel.org
> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>

thanks!

Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>

FYI, on my system(s) the new file is accessible as
/sys/class/tpm/tpm0/version_major.  Does this need to be documented
anywhere?


> ---
>  drivers/char/tpm/tpm-sysfs.c | 34 +++++++++++++++++++++++++++-------
>  1 file changed, 27 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
> index edfa89160010..9372c2d6f0b3 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 major_version_show(struct device *dev,
> +				  struct device_attribute *attr, char *buf)
> +{
> +	struct tpm_chip *chip = to_tpm_chip(dev);
> +
> +	return sprintf(buf, "%s\n", chip->flags & TPM_CHIP_FLAG_TPM2
> +		       ? "2.0" : "1.2");
> +}
> +static DEVICE_ATTR_RO(major_version);
> +
> +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_major_version.attr,
>  	NULL,
>  };
>  
> -static const struct attribute_group tpm_dev_group = {
> -	.attrs = tpm_dev_attrs,
> +static struct attribute *tpm20_dev_attrs[] = {
> +	&dev_attr_major_version.attr,
> +	NULL
> +};
> +
> +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;
>  }

Re: [PATCH] tpm: Add major_version sysfs file

[Jerry Snitselaar]

On Fri Oct 25 19, Mimi Zohar wrote:
>On Fri, 2019-10-25 at 07:28 -0700, Jerry Snitselaar wrote:
>> Easily determining what TCG version a tpm device implements
>> has been a pain point for userspace for a long time, so
>> add a sysfs file to report the tcg version of a tpm device.
>
>Use "TCG" uppercase consistently.
> 
>>
>> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>> Cc: Peter Huewe <peterhuewe@gmx.de>
>> Cc: Jason Gunthorpe <jgg@ziepe.ca>
>> Cc: linux-integrity@vger.kernel.org
>> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
>
>thanks!
>
>Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
>
>FYI, on my system(s) the new file is accessible as
>/sys/class/tpm/tpm0/version_major.  Does this need to be documented
>anywhere?
>
>

Yes, there should be an entry added to
Documentation/ABI/stable/sysfs-class-tpm.
I will fix that up and the TCG not being uppercase in a v2.

Should Documentation/ABI/stable/sysfs-class-tpm updated in
some way to reflect that those are all links under device
now and not actually there.

>> ---
>>  drivers/char/tpm/tpm-sysfs.c | 34 +++++++++++++++++++++++++++-------
>>  1 file changed, 27 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
>> index edfa89160010..9372c2d6f0b3 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 major_version_show(struct device *dev,
>> +				  struct device_attribute *attr, char *buf)
>> +{
>> +	struct tpm_chip *chip = to_tpm_chip(dev);
>> +
>> +	return sprintf(buf, "%s\n", chip->flags & TPM_CHIP_FLAG_TPM2
>> +		       ? "2.0" : "1.2");
>> +}
>> +static DEVICE_ATTR_RO(major_version);
>> +
>> +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_major_version.attr,
>>  	NULL,
>>  };
>>
>> -static const struct attribute_group tpm_dev_group = {
>> -	.attrs = tpm_dev_attrs,
>> +static struct attribute *tpm20_dev_attrs[] = {
>> +	&dev_attr_major_version.attr,
>> +	NULL
>> +};
>> +
>> +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;
>>  }
>

Re: [PATCH] tpm: Add major_version sysfs file

[Mimi Zohar]

On Fri, 2019-10-25 at 11:45 -0700, Jerry Snitselaar wrote:
> On Fri Oct 25 19, Mimi Zohar wrote:
> >On Fri, 2019-10-25 at 07:28 -0700, Jerry Snitselaar wrote:
> >> Easily determining what TCG version a tpm device implements
> >> has been a pain point for userspace for a long time, so
> >> add a sysfs file to report the tcg version of a tpm device.
> >
> >Use "TCG" uppercase consistently.

And "TPM"

> > 
> >>
> >> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> >> Cc: Peter Huewe <peterhuewe@gmx.de>
> >> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> >> Cc: linux-integrity@vger.kernel.org
> >> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
> >
> >thanks!
> >
> >Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> >
> >FYI, on my system(s) the new file is accessible as
> >/sys/class/tpm/tpm0/version_major.  Does this need to be documented
> >anywhere?
> >
> >
> 
> Yes, there should be an entry added to
> Documentation/ABI/stable/sysfs-class-tpm.
> I will fix that up and the TCG not being uppercase in a v2.
> 
> Should Documentation/ABI/stable/sysfs-class-tpm updated in
> some way to reflect that those are all links under device
> now and not actually there.

The importance is that there is a common file that can be used by
userspace applications, instead of having to search for it, not that
it is a link per-se.

Mimi

Re: [PATCH] tpm: Add major_version sysfs file

[Jason Gunthorpe]

On Fri, Oct 25, 2019 at 11:45:22AM -0700, Jerry Snitselaar wrote:
> On Fri Oct 25 19, Mimi Zohar wrote:
> > On Fri, 2019-10-25 at 07:28 -0700, Jerry Snitselaar wrote:
> > > Easily determining what TCG version a tpm device implements
> > > has been a pain point for userspace for a long time, so
> > > add a sysfs file to report the tcg version of a tpm device.
> > 
> > Use "TCG" uppercase consistently.
> >  
> > > 
> > > Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > > Cc: Peter Huewe <peterhuewe@gmx.de>
> > > Cc: Jason Gunthorpe <jgg@ziepe.ca>
> > > Cc: linux-integrity@vger.kernel.org
> > > Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
> > 
> > thanks!
> > 
> > Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> > 
> > FYI, on my system(s) the new file is accessible as
> > /sys/class/tpm/tpm0/version_major.  Does this need to be documented
> > anywhere?
> > 
> > 
> 
> Yes, there should be an entry added to
> Documentation/ABI/stable/sysfs-class-tpm.
> I will fix that up and the TCG not being uppercase in a v2.
> 
> Should Documentation/ABI/stable/sysfs-class-tpm updated in
> some way to reflect that those are all links under device
> now and not actually there.

Applications should not use the link version, that path was a
mistake. The link is for compatability with old userspace.

Jason

Re: [PATCH] tpm: Add major_version sysfs file

[Mimi Zohar]

On Fri, 2019-10-25 at 16:32 -0300, Jason Gunthorpe wrote:
> On Fri, Oct 25, 2019 at 11:45:22AM -0700, Jerry Snitselaar wrote:
> > On Fri Oct 25 19, Mimi Zohar wrote:
> > Yes, there should be an entry added to
> > Documentation/ABI/stable/sysfs-class-tpm.
> > I will fix that up and the TCG not being uppercase in a v2.
> > 
> > Should Documentation/ABI/stable/sysfs-class-tpm updated in
> > some way to reflect that those are all links under device
> > now and not actually there.
> 
> Applications should not use the link version, that path was a
> mistake. The link is for compatability with old userspace.

Are you suggesting that userspace has to search for the device info? 
That makes no sense.

Mimi

Re: [PATCH] tpm: Add major_version sysfs file

[Jarkko Sakkinen]

On Fri, Oct 25, 2019 at 07:28:47AM -0700, Jerry Snitselaar wrote:
> Easily determining what TCG version a tpm device implements
> has been a pain point for userspace for a long time, so
> add a sysfs file to report the tcg version of a tpm device.
> 
> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Cc: Peter Huewe <peterhuewe@gmx.de>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: linux-integrity@vger.kernel.org
> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>

Please use version_major (e.g. if there is ever version_minor
they order nicely alphabetically).

/Jarkko

Re: [PATCH] tpm: Add major_version sysfs file

[Jason Gunthorpe]

On Sun, Oct 27, 2019 at 05:35:41PM +0200, Jarkko Sakkinen wrote:
> On Fri, Oct 25, 2019 at 07:28:47AM -0700, Jerry Snitselaar wrote:
> > Easily determining what TCG version a tpm device implements
> > has been a pain point for userspace for a long time, so
> > add a sysfs file to report the tcg version of a tpm device.
> > 
> > Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > Cc: Peter Huewe <peterhuewe@gmx.de>
> > Cc: Jason Gunthorpe <jgg@ziepe.ca>
> > Cc: linux-integrity@vger.kernel.org
> > Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
> 
> Please use version_major (e.g. if there is ever version_minor
> they order nicely alphabetically).

That is not the convention in sysfs

Jason

Re: [PATCH] tpm: Add major_version sysfs file

[Jason Gunthorpe]

On Fri, Oct 25, 2019 at 03:42:42PM -0400, Mimi Zohar wrote:
> On Fri, 2019-10-25 at 16:32 -0300, Jason Gunthorpe wrote:
> > On Fri, Oct 25, 2019 at 11:45:22AM -0700, Jerry Snitselaar wrote:
> > > On Fri Oct 25 19, Mimi Zohar wrote:
> > > Yes, there should be an entry added to
> > > Documentation/ABI/stable/sysfs-class-tpm.
> > > I will fix that up and the TCG not being uppercase in a v2.
> > > 
> > > Should Documentation/ABI/stable/sysfs-class-tpm updated in
> > > some way to reflect that those are all links under device
> > > now and not actually there.
> > 
> > Applications should not use the link version, that path was a
> > mistake. The link is for compatability with old userspace.
> 
> Are you suggesting that userspace has to search for the device info? 
> That makes no sense.

Why would it have to search?

Jason

Re: [PATCH] tpm: Add major_version sysfs file

[Jarkko Sakkinen]

On Sun, Oct 27, 2019 at 08:00:46PM -0300, Jason Gunthorpe wrote:
> On Sun, Oct 27, 2019 at 05:35:41PM +0200, Jarkko Sakkinen wrote:
> > On Fri, Oct 25, 2019 at 07:28:47AM -0700, Jerry Snitselaar wrote:
> > > Easily determining what TCG version a tpm device implements
> > > has been a pain point for userspace for a long time, so
> > > add a sysfs file to report the tcg version of a tpm device.
> > > 
> > > Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > > Cc: Peter Huewe <peterhuewe@gmx.de>
> > > Cc: Jason Gunthorpe <jgg@ziepe.ca>
> > > Cc: linux-integrity@vger.kernel.org
> > > Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
> > 
> > Please use version_major (e.g. if there is ever version_minor
> > they order nicely alphabetically).
> 
> That is not the convention in sysfs

What is wrong with that name?

/Jarkko