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Re: [PATCH v5 03/17] tpm: return 0 from pcrs_show() when tpm1_pcr_read() fails




On 11/8/18 9:15 AM, Jarkko Sakkinen wrote:
Do not print partial list of PCRs when tpm1_pcr_read() fails but instead
return 0 from pcrs_show(). This is consistent behavior with other sysfs
functions.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>

Reviewed-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>


---
  drivers/char/tpm/tpm-sysfs.c | 13 ++++++-------
  1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 7ed7eb6f906a..928d4e839bb7 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -100,22 +100,21 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
  {
  	cap_t cap;
  	u8 digest[TPM_DIGEST_SIZE];
-	ssize_t rc;
  	u32 i, j, num_pcrs;
  	char *str = buf;
  	struct tpm_chip *chip = to_tpm_chip(dev);

-	rc = tpm1_getcap(chip, TPM_CAP_PROP_PCR, &cap,
-			 "attempting to determine the number of PCRS",
-			 sizeof(cap.num_pcrs));
-	if (rc)
+	if (tpm1_getcap(chip, TPM_CAP_PROP_PCR, &cap,
+			"attempting to determine the number of PCRS",
+			sizeof(cap.num_pcrs)))
  		return 0;

  	num_pcrs = be32_to_cpu(cap.num_pcrs);
  	for (i = 0; i < num_pcrs; i++) {
-		rc = tpm1_pcr_read(chip, i, digest);
-		if (rc)
+		if (tpm1_pcr_read(chip, i, digest)) {
+			str = buf;
  			break;
+		}
  		str += sprintf(str, "PCR-%02d: ", i);
  		for (j = 0; j < TPM_DIGEST_SIZE; j++)
  			str += sprintf(str, "%02X ", digest[j]);