[PATCH 5.11 08/41] KEYS: trusted: Fix TPM reservation for seal/unseal

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: James Bottomley <James.Bottomley@HansenPartnership.com>

[ Upstream commit 9d5171eab462a63e2fbebfccf6026e92be018f20 ]

The original patch 8c657a0590de ("KEYS: trusted: Reserve TPM for seal
and unseal operations") was correct on the mailing list:

https://lore.kernel.org/linux-integrity/20210128235621.127925-4-jarkko@kernel.org/

But somehow got rebased so that the tpm_try_get_ops() in
tpm2_seal_trusted() got lost.  This causes an imbalanced put of the
TPM ops and causes oopses on TIS based hardware.

This fix puts back the lost tpm_try_get_ops()

Fixes: 8c657a0590de ("KEYS: trusted: Reserve TPM for seal and unseal operations")
Reported-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 security/keys/trusted-keys/trusted_tpm2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index e2a0ed5d02f0..c87c4df8703d 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -79,7 +79,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 	if (i == ARRAY_SIZE(tpm2_hash_map))
 		return -EINVAL;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
+	rc = tpm_try_get_ops(chip);
 	if (rc)
 		return rc;
 
-- 
2.30.2