[PATCH v16 12/38] tpm/tpm_tis: Address positive localities in tpm_tis_request_locality()

[Ross Philipson]

From: "Daniel P. Smith" <dpsmith at apertussolutions.com>

Validate that the input locality is within the correct range, as specified
by TCG standards, and increase the locality count also for the positive
localities.

Co-developed-by: Jarkko Sakkinen <jarkko at kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko at kernel.org>
Signed-off-by: Daniel P. Smith <dpsmith at apertussolutions.com>
Signed-off-by: Ross Philipson <ross.philipson at gmail.com>
---
 drivers/char/tpm/tpm_tis_core.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 1fbb74a565f4..70aba05f4ee1 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -179,7 +179,8 @@ static int tpm_tis_relinquish_locality(struct tpm_chip *chip, int l)
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 
 	mutex_lock(&priv->locality_count_mutex);
-	priv->locality_count--;
+	if (priv->locality_count > 0)
+		priv->locality_count--;
 	if (priv->locality_count == 0)
 		__tpm_tis_relinquish_locality(priv, l);
 	mutex_unlock(&priv->locality_count_mutex);
@@ -233,10 +234,16 @@ static int tpm_tis_request_locality(struct tpm_chip *chip, int l)
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 	int ret = 0;
 
+	if (l < 0 || l > TPM_MAX_LOCALITY) {
+		dev_warn(&chip->dev, "%s: failed to request unknown locality: %d\n",
+			 __func__, l);
+		return -EINVAL;
+	}
+
 	mutex_lock(&priv->locality_count_mutex);
 	if (priv->locality_count == 0)
 		ret = __tpm_tis_request_locality(chip, l);
-	if (!ret)
+	if (ret >= 0)
 		priv->locality_count++;
 	mutex_unlock(&priv->locality_count_mutex);
 	return ret;
-- 
2.47.3