linux-kernel - Re: [PATCH] tpm: ibmvtpm: Call tpm2_sessions

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Message-ID: <5427fe09-199b-4b4b-a451-044e8e352595@linux.ibm.com>
Date: Mon, 17 Jun 2024 16:17:59 -0400
From: Stefan Berger <stefanb@...ux.ibm.com>
To: James Bottomley <James.Bottomley@...senPartnership.com>,
        linux-integrity@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        jarkko@...nel.org
Cc: linux-kernel@...r.kernel.org, mpe@...erman.id.au,
        naveen.n.rao@...ux.ibm.com
Subject: Re: [PATCH] tpm: ibmvtpm: Call tpm2_sessions_init() to initialize
 session support



On 6/17/24 16:05, James Bottomley wrote:
> On Mon, 2024-06-17 at 15:56 -0400, Stefan Berger wrote:
>>
>>
>> On 6/17/24 15:42, James Bottomley wrote:
>>> On Mon, 2024-06-17 at 15:34 -0400, Stefan Berger wrote:
>>>> Fix the following type of error message caused by a missing call
>>>> to
>>>> tpm2_sessions_init() in the IBM vTPM driver:
>>>>
>>>> [    2.987131] tpm tpm0: tpm2_load_context: failed with a TPM
>>>> error
>>>> 0x01C4
>>>> [    2.987140] ima: Error Communicating to TPM chip, result: -14
>>>>
>>>> Fixes: d2add27cf2b8 ("tpm: Add NULL primary creation")
>>>> Signed-off-by: Stefan Berger <stefanb@...ux.ibm.com>
>>>> ---
>>>>    drivers/char/tpm/tpm_ibmvtpm.c | 4 ++++
>>>>    1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/drivers/char/tpm/tpm_ibmvtpm.c
>>>> b/drivers/char/tpm/tpm_ibmvtpm.c
>>>> index d3989b257f42..1e5b107d1f3b 100644
>>>> --- a/drivers/char/tpm/tpm_ibmvtpm.c
>>>> +++ b/drivers/char/tpm/tpm_ibmvtpm.c
>>>> @@ -698,6 +698,10 @@ static int tpm_ibmvtpm_probe(struct vio_dev
>>>> *vio_dev,
>>>>                   rc = tpm2_get_cc_attrs_tbl(chip);
>>>>                   if (rc)
>>>>                           goto init_irq_cleanup;
>>>> +
>>>> +               rc = tpm2_sessions_init(chip);
>>>> +               if (rc)
>>>> +                       goto init_irq_cleanup;
>>>
>>> This looks wrong: the whole thing is designed to occur in the
>>> bootstrap
>>> phase from tpm_chip_register() (which tpm_ibmvtpm.c definitely
>>> calls),
>>> so why isn't it happening?
>>
>> Because flags = TPM_OPS_AUTO_STARTUP has not been set for this
>> driver.
>>
> 
> In that case, wouldn't the fix be to move tpm_sessions_init() to
> somewhere in tpm_chip_register() that would then be called by this
> driver?  Having to special case it for every driver that doesn't set
> this flag is going to be a huge pain.

I think the 2nd fix is to set TPM_OPS_AUTO_STARTUP also for the ibmvtpm 
driver like the following patch on top of this one, but after more testing:

 From c6bcd3890f1bdc43d9549fbb39fe388adf756358 Mon Sep 17 00:00:00 2001
From: Stefan Berger <stefanb@...ux.ibm.com>
Date: Mon, 17 Jun 2024 16:05:54 -0400
Subject: [PATCH] tpm: ibmvtpm: Set TPM_OPS_AUTO_STARTUP flag for
  initialization

Set the TPM_OPS_AUTO_STARTUP flag for using common initialization code.
The difference between the old initialization and the new one is that
for TPM 1.2 tpm1_do_selftest and for TPM 2 tpm2_do_selftest will be called.

Signed-off-by: Stefan Berger <stefanb@...ux.ibm.com>
---
  drivers/char/tpm/tpm_ibmvtpm.c | 15 +--------------
  1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index 1e5b107d1f3b..76d048f63d55 100644
--- a/drivers/char/tpm/tpm_ibmvtpm.c
+++ b/drivers/char/tpm/tpm_ibmvtpm.c
@@ -450,6 +450,7 @@ static bool tpm_ibmvtpm_req_canceled(struct tpm_chip 
*chip, u8 status)
  }

  static const struct tpm_class_ops tpm_ibmvtpm = {
+       .flags = TPM_OPS_AUTO_STARTUP,
         .recv = tpm_ibmvtpm_recv,
         .send = tpm_ibmvtpm_send,
         .cancel = tpm_ibmvtpm_cancel,
@@ -690,20 +691,6 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev,
         if (!strcmp(id->compat, "IBM,vtpm20"))
                 chip->flags |= TPM_CHIP_FLAG_TPM2;

-       rc = tpm_get_timeouts(chip);
-       if (rc)
-               goto init_irq_cleanup;
-
-       if (chip->flags & TPM_CHIP_FLAG_TPM2) {
-               rc = tpm2_get_cc_attrs_tbl(chip);
-               if (rc)
-                       goto init_irq_cleanup;
-
-               rc = tpm2_sessions_init(chip);
-               if (rc)
-                       goto init_irq_cleanup;
-       }
-
         return tpm_chip_register(chip);
  init_irq_cleanup:
         do {
--
2.45.2

Regards,
    Stefan

> 
> I think the only reason it's down that far is that it should only be
> called for TPM2 code so it was avoiding doing the check twice, so
> something like this >
> James
> 
> ---
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 5da134f12c9a..4280cbb0f0b1 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -347,6 +347,12 @@ int tpm_auto_startup(struct tpm_chip *chip)
>   {
>   	int rc;
>   
> +	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> +		rc = tpm2_sessions_init(chip);
> +		if (rc)
> +			return rc;
> +	}
> +
>   	if (!(chip->ops->flags & TPM_OPS_AUTO_STARTUP))
>   		return 0;
>   
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index 1e856259219e..b4f85c8cdbb6 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -773,11 +773,6 @@ int tpm2_auto_startup(struct tpm_chip *chip)
>   		rc = 0;
>   	}
>   
> -	if (rc)
> -		goto out;
> -
> -	rc = tpm2_sessions_init(chip);
> -
>   out:
>   	/*
>   	 * Infineon TPM in field upgrade mode will return no data for the number
>