tpm2_sessions_init() does not ignore the result of
tpm2_create_null_primary(). Address this by returning -ENODEV to the
caller. Given that upper layers cannot help healing the situation
further, deal with the TPM error here by

Cc: stable@vger.kernel.org # v6.10+
Fixes: d2add27cf2b8 ("tpm: Add NULL primary creation")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v7:
- Add the error message back but fix it up a bit:
  1. Remove 'TPM:' given dev_err().
  2. s/NULL/null/ as this has nothing to do with the macro in libc.
  3. Fix the reasoning: null key creation failed
v6:
- Address:
  https://lore.kernel.org/linux-integrity/69c893e7-6b87-4daa-80db-44d1120e80fe@linux.ibm.com/
  as TPM RC is taken care of at the call site. Add also the missing
  documentation for the return values.
v5:
- Do not print klog messages on error, as tpm2_save_context() already
  takes care of this.
v4:
- Fixed up stable version.
v3:
- Handle TPM and POSIX error separately and return -ENODEV always back
  to the caller.
v2:
- Refined the commit message.
---
 drivers/char/tpm/tpm2-sessions.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index d3521aadd43e..1e12e0b2492e 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -1347,14 +1347,21 @@ static int tpm2_create_null_primary(struct tpm_chip *chip)
  *
  * Derive and context save the null primary and allocate memory in the
  * struct tpm_chip for the authorizations.
+ *
+ * Return:
+ * * 0		- OK
+ * * -errno	- A system error
+ * * TPM_RC	- A TPM error
  */
 int tpm2_sessions_init(struct tpm_chip *chip)
 {
 	int rc;
 
 	rc = tpm2_create_null_primary(chip);
-	if (rc)
-		dev_err(&chip->dev, "TPM: security failed (NULL seed derivation): %d\n", rc);
+	if (rc) {
+		dev_err(&chip->dev, "null primary key creation failed with %d\n", rc);
+		return rc;
+	}
 
 	chip->auth = kmalloc(sizeof(*chip->auth), GFP_KERNEL);
 	if (!chip->auth)
-- 
2.47.0

On 10/21/24 1:39 AM, Jarkko Sakkinen wrote:
> tpm2_sessions_init() does not ignore the result of
> tpm2_create_null_primary(). Address this by returning -ENODEV to the
> caller. Given that upper layers cannot help healing the situation

It looks like returning -ENODEV applied to a previous version of the patch.

> further, deal with the TPM error here by

This sounds like an incomplete sentence...

> 
> Cc: stable@vger.kernel.org # v6.10+
> Fixes: d2add27cf2b8 ("tpm: Add NULL primary creation")
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
> v7:
> - Add the error message back but fix it up a bit:
>    1. Remove 'TPM:' given dev_err().
>    2. s/NULL/null/ as this has nothing to do with the macro in libc.
>    3. Fix the reasoning: null key creation failed
> v6:
> - Address:
>    https://lore.kernel.org/linux-integrity/69c893e7-6b87-4daa-80db-44d1120e80fe@linux.ibm.com/
>    as TPM RC is taken care of at the call site. Add also the missing
>    documentation for the return values.
> v5:
> - Do not print klog messages on error, as tpm2_save_context() already
>    takes care of this.
> v4:
> - Fixed up stable version.
> v3:
> - Handle TPM and POSIX error separately and return -ENODEV always back
>    to the caller.
> v2:
> - Refined the commit message.
> ---
>   drivers/char/tpm/tpm2-sessions.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
> index d3521aadd43e..1e12e0b2492e 100644
> --- a/drivers/char/tpm/tpm2-sessions.c
> +++ b/drivers/char/tpm/tpm2-sessions.c
> @@ -1347,14 +1347,21 @@ static int tpm2_create_null_primary(struct tpm_chip *chip)
>    *
>    * Derive and context save the null primary and allocate memory in the
>    * struct tpm_chip for the authorizations.
> + *
> + * Return:
> + * * 0		- OK
> + * * -errno	- A system error
> + * * TPM_RC	- A TPM error
>    */
>   int tpm2_sessions_init(struct tpm_chip *chip)
>   {
>   	int rc;
>   
>   	rc = tpm2_create_null_primary(chip);
> -	if (rc)
> -		dev_err(&chip->dev, "TPM: security failed (NULL seed derivation): %d\n", rc);
> +	if (rc) {
> +		dev_err(&chip->dev, "null primary key creation failed with %d\n", rc);
> +		return rc;
> +	}
>   
>   	chip->auth = kmalloc(sizeof(*chip->auth), GFP_KERNEL);
>   	if (!chip->auth)

On Wed Oct 23, 2024 at 8:46 PM EEST, Stefan Berger wrote:
>
>
> On 10/21/24 1:39 AM, Jarkko Sakkinen wrote:
> > tpm2_sessions_init() does not ignore the result of
> > tpm2_create_null_primary(). Address this by returning -ENODEV to the
> > caller. Given that upper layers cannot help healing the situation
>
> It looks like returning -ENODEV applied to a previous version of the patch.
>
> > further, deal with the TPM error here by
>
> This sounds like an incomplete sentence...

It looks like totally corrupted, thanks for the remark.

"tpm2_sessions_init() ignores the return value of tpm2_create_null_primary().
Fail early and return back to the caller if it fails. Fine-tune the error
message while at it."
	
Is this sufficient?

BR, Jarkko