2021-07-19 13:37:27

by Borys Movchan

Subject: [PATCH] tpm: Add Upgrade/Reduced mode support for TPM2 modules

On some systems, especially embedded, TPM might start in
Upgrade/Reduced mode due to the previous failure of a firmware
upgrade process. Allow the TPM driver to handle such situations
properly. Enables a possibility for userspace application to
finalize TPM upgrade or recovery if required.

Signed-off-by: Borys Movchan <[email protected]>
---
drivers/char/tpm/tpm-chip.c | 23 +++++++++++++++--------
drivers/char/tpm/tpm2-cmd.c | 12 ++++++++++--
include/linux/tpm.h | 1 +
3 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index ddaeceb7e109..ff2367c447fb 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -574,20 +574,25 @@ static int tpm_get_pcr_allocation(struct tpm_chip *chip)
int tpm_chip_register(struct tpm_chip *chip)
{
int rc;
+ bool limited_mode = false;

rc = tpm_chip_start(chip);
if (rc)
return rc;
rc = tpm_auto_startup(chip);
- if (rc) {
+ if (rc == -EIO) {
+ limited_mode = true;
+ } else if (rc) {
tpm_chip_stop(chip);
return rc;
}

- rc = tpm_get_pcr_allocation(chip);
- tpm_chip_stop(chip);
- if (rc)
- return rc;
+ if (!limited_mode) {
+ rc = tpm_get_pcr_allocation(chip);
+ tpm_chip_stop(chip);
+ if (rc)
+ return rc;
+ }

tpm_sysfs_add_device(chip);

@@ -595,9 +600,11 @@ int tpm_chip_register(struct tpm_chip *chip)

tpm_add_ppi(chip);

- rc = tpm_add_hwrng(chip);
- if (rc)
- goto out_ppi;
+ if (!limited_mode) {
+ rc = tpm_add_hwrng(chip);
+ if (rc)
+ goto out_ppi;
+ }

rc = tpm_add_char_device(chip);
if (rc)
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index a25815a6f625..7468353ed67d 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -718,7 +718,8 @@ static int tpm2_startup(struct tpm_chip *chip)
* sequence
* @chip: TPM chip to use
*
- * Returns 0 on success, < 0 in case of fatal error.
+ * Returns 0 on success, -ENODEV in case of fatal error,
+ * -EIO in case of Reduced/Upgrade mode
*/
int tpm2_auto_startup(struct tpm_chip *chip)
{
@@ -729,7 +730,10 @@ int tpm2_auto_startup(struct tpm_chip *chip)
goto out;

rc = tpm2_do_selftest(chip);
- if (rc && rc != TPM2_RC_INITIALIZE)
+ if (rc == TPM2_RC_UPGRADE) {
+ rc = -EIO;
+ goto out;
+ } else if (rc && rc != TPM2_RC_INITIALIZE)
goto out;

if (rc == TPM2_RC_INITIALIZE) {
@@ -743,6 +747,10 @@ int tpm2_auto_startup(struct tpm_chip *chip)
}

rc = tpm2_get_cc_attrs_tbl(chip);
+ if (rc) { /* Succeeded until here, but failed -> reduced mode */
+ rc = -EIO;
+ goto out;
+ }

out:
if (rc > 0)
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index aa11fe323c56..e873c42907f0 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -207,6 +207,7 @@ enum tpm2_return_codes {
TPM2_RC_INITIALIZE = 0x0100, /* RC_VER1 */
TPM2_RC_FAILURE = 0x0101,
TPM2_RC_DISABLED = 0x0120,
+ TPM2_RC_UPGRADE = 0x012D,
TPM2_RC_COMMAND_CODE = 0x0143,
TPM2_RC_TESTING = 0x090A, /* RC_WARN */
TPM2_RC_REFERENCE_H0 = 0x0910,
--
2.20.1

2021-07-27 03:00:27

by Jarkko Sakkinen

Subject: Re: [PATCH] tpm: Add Upgrade/Reduced mode support for TPM2 modules

On Mon, Jul 19, 2021 at 03:37:17PM +0200, Borys Movchan wrote:
> On some systems, especially embedded, TPM might start in
> Upgrade/Reduced mode due to the previous failure of a firmware
> upgrade process. Allow the TPM driver to handle such situations
> properly. Enables a possibility for userspace application to
> finalize TPM upgrade or recovery if required.


Please add short explanation what you mean by upgrade/reduced mode.

Maybe for clarity speak about upgrade mode.

>
> Signed-off-by: Borys Movchan <[email protected]>
> ---
> drivers/char/tpm/tpm-chip.c | 23 +++++++++++++++--------
> drivers/char/tpm/tpm2-cmd.c | 12 ++++++++++--
> include/linux/tpm.h | 1 +
> 3 files changed, 26 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index ddaeceb7e109..ff2367c447fb 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -574,20 +574,25 @@ static int tpm_get_pcr_allocation(struct tpm_chip *chip)
> int tpm_chip_register(struct tpm_chip *chip)
> {
> int rc;
> + bool limited_mode = false;
>
> rc = tpm_chip_start(chip);
> if (rc)
> return rc;
> rc = tpm_auto_startup(chip);
> - if (rc) {
> + if (rc == -EIO) {
> + limited_mode = true;
> + } else if (rc) {
> tpm_chip_stop(chip);
> return rc;
> }
>
> - rc = tpm_get_pcr_allocation(chip);
> - tpm_chip_stop(chip);
> - if (rc)
> - return rc;
> + if (!limited_mode) {
> + rc = tpm_get_pcr_allocation(chip);
> + tpm_chip_stop(chip);
> + if (rc)
> + return rc;
> + }
>
> tpm_sysfs_add_device(chip);
>
> @@ -595,9 +600,11 @@ int tpm_chip_register(struct tpm_chip *chip)
>
> tpm_add_ppi(chip);
>
> - rc = tpm_add_hwrng(chip);
> - if (rc)
> - goto out_ppi;
> + if (!limited_mode) {
> + rc = tpm_add_hwrng(chip);
> + if (rc)
> + goto out_ppi;
> + }
>
> rc = tpm_add_char_device(chip);
> if (rc)
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index a25815a6f625..7468353ed67d 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -718,7 +718,8 @@ static int tpm2_startup(struct tpm_chip *chip)
> * sequence
> * @chip: TPM chip to use
> *
> - * Returns 0 on success, < 0 in case of fatal error.
> + * Returns 0 on success, -ENODEV in case of fatal error,
> + * -EIO in case of Reduced/Upgrade mode
> */
> int tpm2_auto_startup(struct tpm_chip *chip)
> {
> @@ -729,7 +730,10 @@ int tpm2_auto_startup(struct tpm_chip *chip)
> goto out;
>
> rc = tpm2_do_selftest(chip);
> - if (rc && rc != TPM2_RC_INITIALIZE)
> + if (rc == TPM2_RC_UPGRADE) {
> + rc = -EIO;
> + goto out;
> + } else if (rc && rc != TPM2_RC_INITIALIZE)
> goto out;
>
> if (rc == TPM2_RC_INITIALIZE) {
> @@ -743,6 +747,10 @@ int tpm2_auto_startup(struct tpm_chip *chip)
> }
>
> rc = tpm2_get_cc_attrs_tbl(chip);
> + if (rc) { /* Succeeded until here, but failed -> reduced mode */
> + rc = -EIO;
> + goto out;
> + }
>
> out:
> if (rc > 0)
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index aa11fe323c56..e873c42907f0 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -207,6 +207,7 @@ enum tpm2_return_codes {
> TPM2_RC_INITIALIZE = 0x0100, /* RC_VER1 */
> TPM2_RC_FAILURE = 0x0101,
> TPM2_RC_DISABLED = 0x0120,
> + TPM2_RC_UPGRADE = 0x012D,
> TPM2_RC_COMMAND_CODE = 0x0143,
> TPM2_RC_TESTING = 0x090A, /* RC_WARN */
> TPM2_RC_REFERENCE_H0 = 0x0910,
> --
> 2.20.1
>
>

/Jarkko

2021-07-28 11:06:51

by Borys Movchan

Subject: Re: [PATCH] tpm: Add Upgrade/Reduced mode support for TPM2 modules

On 7/27/21 4:58 AM, Jarkko Sakkinen wrote:
> On Mon, Jul 19, 2021 at 03:37:17PM +0200, Borys Movchan wrote:
> > On some systems, especially embedded, TPM might start in
> > Upgrade/Reduced mode due to the previous failure of a firmware
> > upgrade process. Allow the TPM driver to handle such situations
> > properly. Enables a possibility for userspace application to
> > finalize TPM upgrade or recovery if required.
>
>
> Please add short explanation what you mean by upgrade/reduced mode.
>
> Maybe for clarity speak about upgrade mode.

I have send v2 patch with updated commit message and some notes.

Hope that would be more clear.

>
> >
> > Signed-off-by: Borys Movchan <[email protected]>
> > ---
> >? drivers/char/tpm/tpm-chip.c | 23 +++++++++++++++--------
> >? drivers/char/tpm/tpm2-cmd.c | 12 ++++++++++--
> >? include/linux/tpm.h???????? |? 1 +
> >? 3 files changed, 26 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> > index ddaeceb7e109..ff2367c447fb 100644
> > --- a/drivers/char/tpm/tpm-chip.c
> > +++ b/drivers/char/tpm/tpm-chip.c
> > @@ -574,20 +574,25 @@ static int tpm_get_pcr_allocation(struct
> tpm_chip *chip)
> >? int tpm_chip_register(struct tpm_chip *chip)
> >? {
> >??????? int rc;
> > +???? bool limited_mode = false;
> >
> >??????? rc = tpm_chip_start(chip);
> >??????? if (rc)
> >??????????????? return rc;
> >??????? rc = tpm_auto_startup(chip);
> > -???? if (rc) {
> > +???? if (rc == -EIO) {
> > +???????????? limited_mode = true;
> > +???? } else if (rc) {
> >??????????????? tpm_chip_stop(chip);
> >??????????????? return rc;
> >??????? }
> >
> > -???? rc = tpm_get_pcr_allocation(chip);
> > -???? tpm_chip_stop(chip);
> > -???? if (rc)
> > -???????????? return rc;
> > +???? if (!limited_mode) {
> > +???????????? rc = tpm_get_pcr_allocation(chip);
> > +???????????? tpm_chip_stop(chip);
> > +???????????? if (rc)
> > +???????????????????? return rc;
> > +???? }
> >
> >??????? tpm_sysfs_add_device(chip);
> >
> > @@ -595,9 +600,11 @@ int tpm_chip_register(struct tpm_chip *chip)
> >
> >??????? tpm_add_ppi(chip);
> >
> > -???? rc = tpm_add_hwrng(chip);
> > -???? if (rc)
> > -???????????? goto out_ppi;
> > +???? if (!limited_mode) {
> > +???????????? rc = tpm_add_hwrng(chip);
> > +???????????? if (rc)
> > +???????????????????? goto out_ppi;
> > +???? }
> >
> >??????? rc = tpm_add_char_device(chip);
> >??????? if (rc)
> > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> > index a25815a6f625..7468353ed67d 100644
> > --- a/drivers/char/tpm/tpm2-cmd.c
> > +++ b/drivers/char/tpm/tpm2-cmd.c
> > @@ -718,7 +718,8 @@ static int tpm2_startup(struct tpm_chip *chip)
> >?? *???????????????????? sequence
> >?? * @chip: TPM chip to use
> >?? *
> > - * Returns 0 on success, < 0 in case of fatal error.
> > + * Returns 0 on success, -ENODEV in case of fatal error,
> > + *?????? -EIO in case of Reduced/Upgrade mode
> >?? */
> >? int tpm2_auto_startup(struct tpm_chip *chip)
> >? {
> > @@ -729,7 +730,10 @@ int tpm2_auto_startup(struct tpm_chip *chip)
> >??????????????? goto out;
> >
> >??????? rc = tpm2_do_selftest(chip);
> > -???? if (rc && rc != TPM2_RC_INITIALIZE)
> > +???? if (rc == TPM2_RC_UPGRADE) {
> > +???????????? rc = -EIO;
> > +???????????? goto out;
> > +???? } else if (rc && rc != TPM2_RC_INITIALIZE)
> >??????????????? goto out;
> >
> >??????? if (rc == TPM2_RC_INITIALIZE) {
> > @@ -743,6 +747,10 @@ int tpm2_auto_startup(struct tpm_chip *chip)
> >??????? }
> >
> >??????? rc = tpm2_get_cc_attrs_tbl(chip);
> > +???? if (rc) { /* Succeeded until here, but failed -> reduced mode */
> > +???????????? rc = -EIO;
> > +???????????? goto out;
> > +???? }
> >
> >? out:
> >??????? if (rc > 0)
> > diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> > index aa11fe323c56..e873c42907f0 100644
> > --- a/include/linux/tpm.h
> > +++ b/include/linux/tpm.h
> > @@ -207,6 +207,7 @@ enum tpm2_return_codes {
> >??????? TPM2_RC_INITIALIZE????? = 0x0100, /* RC_VER1 */
> >??????? TPM2_RC_FAILURE???????? = 0x0101,
> >??????? TPM2_RC_DISABLED??????? = 0x0120,
> > +???? TPM2_RC_UPGRADE???????? = 0x012D,
> >??????? TPM2_RC_COMMAND_CODE??? = 0x0143,
> >??????? TPM2_RC_TESTING???????? = 0x090A, /* RC_WARN */
> >??????? TPM2_RC_REFERENCE_H0??? = 0x0910,
> > --
> > 2.20.1
> >
> >
>
> /Jarkko

Kind regards,

Borys