linux-kernel - [PATCH v7 1/5] tpm: Return on tpm2_create_null

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Message-ID: <20241021053921.33274-2-jarkko@kernel.org>
Date: Mon, 21 Oct 2024 08:39:15 +0300
From: Jarkko Sakkinen <jarkko@...nel.org>
To: linux-integrity@...r.kernel.org,
	Peter Huewe <peterhuewe@....de>,
	Jarkko Sakkinen <jarkko@...nel.org>,
	Jason Gunthorpe <jgg@...pe.ca>,
	James Bottomley <James.Bottomley@...senPartnership.com>
Cc: David Howells <dhowells@...hat.com>,
	Mimi Zohar <zohar@...ux.ibm.com>,
	Roberto Sassu <roberto.sassu@...wei.com>,
	Stefan Berger <stefanb@...ux.ibm.com>,
	linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: [PATCH v7 1/5] tpm: Return on tpm2_create_null_primary() failure

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@...r.kernel.org # v6.10+
Fixes: d2add27cf2b8 ("tpm: Add NULL primary creation")
Signed-off-by: Jarkko Sakkinen <jarkko@...nel.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