Re: [PATCH v3 2/2] tests: tpm: Skip over pcrUpdateCounter byte in result comparison

[Marc-André Lureau]

On Wed, Jul 8, 2020 at 12:16 AM Stefan Berger
<stefanb@linux.vnet.ibm.com> wrote:
>
> The TPM 2 code in libtpms was fixed to handle the PCR 'TCB group' according
> to the PCClient profile. The change of the PCRs belonging to the 'TCB group'
> now affects the pcrUpdateCounter in the TPM2_PCRRead() responses where its
> value is now different (typically lower by '1') than what it was before. To
> not fail the tests, we skip the comparison of the 14th byte, which
> represents the pcrUpdateCounter.
>
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

> ---
>  tests/qtest/tpm-util.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/tests/qtest/tpm-util.c b/tests/qtest/tpm-util.c
> index 34efae8f18..58a9593745 100644
> --- a/tests/qtest/tpm-util.c
> +++ b/tests/qtest/tpm-util.c
> @@ -139,7 +139,11 @@ void tpm_util_pcrread(QTestState *s, tx_func *tx,
>
>      tx(s, tpm_pcrread, sizeof(tpm_pcrread), buffer, sizeof(buffer));
>
> -    g_assert_cmpmem(buffer, exp_resp_size, exp_resp, exp_resp_size);
> +    /* skip pcrUpdateCounter (14th byte) in comparison */
> +    g_assert(exp_resp_size >= 15);
> +    g_assert_cmpmem(buffer, 13, exp_resp, 13);
> +    g_assert_cmpmem(&buffer[14], exp_resp_size - 14,
> +                    &exp_resp[14], exp_resp_size - 14);
>  }
>
>  bool tpm_util_swtpm_has_tpm2(void)
> --
> 2.24.1
>