Re: [PATCH v3 03/16] tpm: return 0 from pcrs_show() when tpm1_pcr_read() fails

Stefan Berger
2018-11-05T21:55:02Z

On 11/4/18 8:45 PM, 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@linux.intel.com>
> ---
> drivers/char/tpm/tpm-sysfs.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
> index 7ed7eb6f906a..d3b05c7526c8 100644
> --- a/drivers/char/tpm/tpm-sysfs.c
> +++ b/drivers/char/tpm/tpm-sysfs.c
> @@ -115,13 +115,15 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
> for (i = 0; i < num_pcrs; i++) {
> rc = tpm1_pcr_read(chip, i, digest);
> if (rc)
> - break;
> + goto out;

Previous patch said "Return zero when tpm_buf_init() fails as we do for
other functions in tpm-sysfs.c.". Why not return 0 in this case as well?

> str += sprintf(str, "PCR-%02d: ", i);
> for (j = 0; j < TPM_DIGEST_SIZE; j++)
> str += sprintf(str, "%02X ", digest[j]);
> str += sprintf(str, "\n");
> }
> - return str - buf;
> + rc = str - buf;
> +out:
> + return rc;
> }
> static DEVICE_ATTR_RO(pcrs);
>