2022-06-03 12:57:47

by Stefan Mahnke-Hartmann

Subject: [PATCH v3] tpm: Add upgrade/reduced mode support for TPM1.2 modules

In case a TPM in failure mode is detected, the TPM should be accessible
through a transparent communication channel for analysing purposes (e.g.
TPM_GetTestResult) or a field upgrade. Since a TPM in failure mode has
similar reduced functionality as in field upgrade mode, the flag
TPM_CHIP_FLAG_FIRMWARE_UPGRADE is also valid.

As described in TCG TPM Main Part1 Design Principles, Revision 116,
chapter 9.2.1. the TPM also allows an update function in case a TPM is
in failure mode.

If the TPM in failure mode is detected, the function tpm1_auto_startup()
sets TPM_CHIP_FLAG_FIRMWARE_UPGRADE flag, which is used later during
driver initialization/deinitialization to disable functionality which
makes no sense or will fail in the current TPM state. The following
functionality is affected:
* Do not register TPM as a hwrng
* Do not get pcr allocation
* Do not register sysfs entries which provide information impossible to
obtain in limited mode

Signed-off-by: Stefan Mahnke-Hartmann <[email protected]>
---
Changelog:
* v3:
* Change kernel messages

drivers/char/tpm/tpm.h | 1 +
drivers/char/tpm/tpm1-cmd.c | 7 ++++++-
2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 2163c6ee0d36..24ee4e1cc452 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -55,6 +55,7 @@ enum tpm_addr {
#define TPM_WARN_DOING_SELFTEST 0x802
#define TPM_ERR_DEACTIVATED 0x6
#define TPM_ERR_DISABLED 0x7
+#define TPM_ERR_FAILEDSELFTEST 0x1C
#define TPM_ERR_INVALID_POSTINIT 38

#define TPM_TAG_RQU_COMMAND 193
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index f7dc986fa4a0..cf64c7385105 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -709,7 +709,12 @@ int tpm1_auto_startup(struct tpm_chip *chip)
if (rc)
goto out;
rc = tpm1_do_selftest(chip);
- if (rc) {
+ if (rc == TPM_ERR_FAILEDSELFTEST) {
+ dev_warn(&chip->dev, "TPM self test failed, switching to the firmware upgrade mode\n");
+ /* A TPM in this state possibly allows or needs a firmware upgrade */
+ chip->flags |= TPM_CHIP_FLAG_FIRMWARE_UPGRADE;
+ return 0;
+ } else if (rc) {
dev_err(&chip->dev, "TPM self test failed\n");
goto out;
}
--
2.25.1

2022-06-07 17:42:42

by Jarkko Sakkinen

Subject: Re: [PATCH v3] tpm: Add upgrade/reduced mode support for TPM1.2 modules

On Tue, Jun 07, 2022 at 12:49:11PM +0300, Jarkko Sakkinen wrote:
> On Fri, Jun 03, 2022 at 10:41:58AM +0200, Stefan Mahnke-Hartmann wrote:
> > In case a TPM in failure mode is detected, the TPM should be accessible
> > through a transparent communication channel for analysing purposes (e.g.
> > TPM_GetTestResult) or a field upgrade. Since a TPM in failure mode has
> > similar reduced functionality as in field upgrade mode, the flag
> > TPM_CHIP_FLAG_FIRMWARE_UPGRADE is also valid.
> >
> > As described in TCG TPM Main Part1 Design Principles, Revision 116,
> > chapter 9.2.1. the TPM also allows an update function in case a TPM is
> > in failure mode.
> >
> > If the TPM in failure mode is detected, the function tpm1_auto_startup()
> > sets TPM_CHIP_FLAG_FIRMWARE_UPGRADE flag, which is used later during
> > driver initialization/deinitialization to disable functionality which
> > makes no sense or will fail in the current TPM state. The following
> > functionality is affected:
> > * Do not register TPM as a hwrng
> > * Do not get pcr allocation
> > * Do not register sysfs entries which provide information impossible to
> > obtain in limited mode
> >
> > Signed-off-by: Stefan Mahnke-Hartmann <[email protected]>
> > ---
> > Changelog:
> > * v3:
> > * Change kernel messages
> >
> > drivers/char/tpm/tpm.h | 1 +
> > drivers/char/tpm/tpm1-cmd.c | 7 ++++++-
> > 2 files changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> > index 2163c6ee0d36..24ee4e1cc452 100644
> > --- a/drivers/char/tpm/tpm.h
> > +++ b/drivers/char/tpm/tpm.h
> > @@ -55,6 +55,7 @@ enum tpm_addr {
> > #define TPM_WARN_DOING_SELFTEST 0x802
> > #define TPM_ERR_DEACTIVATED 0x6
> > #define TPM_ERR_DISABLED 0x7
> > +#define TPM_ERR_FAILEDSELFTEST 0x1C
> > #define TPM_ERR_INVALID_POSTINIT 38
> >
> > #define TPM_TAG_RQU_COMMAND 193
> > diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
> > index f7dc986fa4a0..cf64c7385105 100644
> > --- a/drivers/char/tpm/tpm1-cmd.c
> > +++ b/drivers/char/tpm/tpm1-cmd.c
> > @@ -709,7 +709,12 @@ int tpm1_auto_startup(struct tpm_chip *chip)
> > if (rc)
> > goto out;
> > rc = tpm1_do_selftest(chip);
> > - if (rc) {
> > + if (rc == TPM_ERR_FAILEDSELFTEST) {
> > + dev_warn(&chip->dev, "TPM self test failed, switching to the firmware upgrade mode\n");
> > + /* A TPM in this state possibly allows or needs a firmware upgrade */
> > + chip->flags |= TPM_CHIP_FLAG_FIRMWARE_UPGRADE;
> > + return 0;
> > + } else if (rc) {
> > dev_err(&chip->dev, "TPM self test failed\n");
> > goto out;
> > }
> > --
> > 2.25.1
> >
>
> I think this looks good now, thanks for patience:
>
> Reviewed-by: Jarkko Sakkinen <[email protected]>

applied

BR, Jarkko

2022-06-08 02:53:59

by Jarkko Sakkinen

Subject: Re: [PATCH v3] tpm: Add upgrade/reduced mode support for TPM1.2 modules

On Fri, Jun 03, 2022 at 10:41:58AM +0200, Stefan Mahnke-Hartmann wrote:
> In case a TPM in failure mode is detected, the TPM should be accessible
> through a transparent communication channel for analysing purposes (e.g.
> TPM_GetTestResult) or a field upgrade. Since a TPM in failure mode has
> similar reduced functionality as in field upgrade mode, the flag
> TPM_CHIP_FLAG_FIRMWARE_UPGRADE is also valid.
>
> As described in TCG TPM Main Part1 Design Principles, Revision 116,
> chapter 9.2.1. the TPM also allows an update function in case a TPM is
> in failure mode.
>
> If the TPM in failure mode is detected, the function tpm1_auto_startup()
> sets TPM_CHIP_FLAG_FIRMWARE_UPGRADE flag, which is used later during
> driver initialization/deinitialization to disable functionality which
> makes no sense or will fail in the current TPM state. The following
> functionality is affected:
> * Do not register TPM as a hwrng
> * Do not get pcr allocation
> * Do not register sysfs entries which provide information impossible to
> obtain in limited mode
>
> Signed-off-by: Stefan Mahnke-Hartmann <[email protected]>
> ---
> Changelog:
> * v3:
> * Change kernel messages
>
> drivers/char/tpm/tpm.h | 1 +
> drivers/char/tpm/tpm1-cmd.c | 7 ++++++-
> 2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 2163c6ee0d36..24ee4e1cc452 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -55,6 +55,7 @@ enum tpm_addr {
> #define TPM_WARN_DOING_SELFTEST 0x802
> #define TPM_ERR_DEACTIVATED 0x6
> #define TPM_ERR_DISABLED 0x7
> +#define TPM_ERR_FAILEDSELFTEST 0x1C
> #define TPM_ERR_INVALID_POSTINIT 38
>
> #define TPM_TAG_RQU_COMMAND 193
> diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
> index f7dc986fa4a0..cf64c7385105 100644
> --- a/drivers/char/tpm/tpm1-cmd.c
> +++ b/drivers/char/tpm/tpm1-cmd.c
> @@ -709,7 +709,12 @@ int tpm1_auto_startup(struct tpm_chip *chip)
> if (rc)
> goto out;
> rc = tpm1_do_selftest(chip);
> - if (rc) {
> + if (rc == TPM_ERR_FAILEDSELFTEST) {
> + dev_warn(&chip->dev, "TPM self test failed, switching to the firmware upgrade mode\n");
> + /* A TPM in this state possibly allows or needs a firmware upgrade */
> + chip->flags |= TPM_CHIP_FLAG_FIRMWARE_UPGRADE;
> + return 0;
> + } else if (rc) {
> dev_err(&chip->dev, "TPM self test failed\n");
> goto out;
> }
> --
> 2.25.1
>

I think this looks good now, thanks for patience:

Reviewed-by: Jarkko Sakkinen <[email protected]>

BR, Jarkko