On Wed, 2018-11-07 at 11:44 +0530, Nayna Jain wrote:

On 11/06/2018 08:31 PM, Roberto Sassu wrote:

quoted

@@ -878,11 +877,14 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
  	if (rc)
  		goto out;

-	count = be32_to_cpup(
+	chip->nr_active_banks = be32_to_cpup(
  		(__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);

As per my understanding, the count in the TPML_PCR_SELECTION represent 
the number of possible banks and not the number of active banks.
TCG Structures Spec for TPM 2.0 - Table 102 mentions this as explanation 
of #TPM_RC_SIZE.

Instead of storing the result in a local variable, the only change
here is saving the result in the chip info (nr_active_banks).
 Everything else remains the same.

quoted

-	if (count > ARRAY_SIZE(chip->active_banks)) {
-		rc = -ENODEV;
+	chip->active_banks = kmalloc_array(chip->nr_active_banks,
+					   sizeof(*chip->active_banks),
+					   GFP_KERNEL);

With this change, the exact number of banks can be allocated, as done
here.  Nice! 

Mimi

quoted

+	if (!chip->active_banks) {
+		rc = -ENOMEM;
  		goto out;
  	}