keys/trusted_keys: fix handle passed to tpm_buf_append_name during unseal

TPM2_Unseal[1] expects the handle of a loaded data object, and not the
handle of the parent key. But the tpm2_unseal_cmd provides the parent
keyhandle instead of blob_handle for the session HMAC calculation. This
causes unseal to fail.

Fix this by passing blob_handle to tpm_buf_append_name().

References:

[1] trustedcomputinggroup.org/wp-content/uploads/
    Trusted-Platform-Module-2.0-Library-Part-3-Version-184_pub.pdf

Fixes: 6e9722e ("tpm2-sessions: Fix out of range indexing in name_size")
Signed-off-by: Srish Srinivasan <ssrish@linux.ibm.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

Author: ssrish17

security/keys/trusted-keys/trusted_tpm2.c

@@ -465,7 +465,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 }
 
 /**
- * tpm2_unseal_cmd() - execute a TPM2_Unload command
+ * tpm2_unseal_cmd() - execute a TPM2_Unseal command
  *
  * @chip: TPM chip to use
  * @payload: the key data in clear and encrypted form
@@ -498,7 +498,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 		return rc;
 	}
 
-	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	rc = tpm_buf_append_name(chip, &buf, blob_handle, NULL);
 	if (rc)
 		goto out;