dtrust: read serial number from EF.GDO

This is necessary, because for D-Trust Cards 5.x the CardOS command
requires PACE authentication.

src/libopensc/card-dtrust.c

@@ -184,20 +184,14 @@ static int
 _dtrust_get_serialnr(sc_card_t *card)
 {
  int r;
- u8 buf[32];
-
- r = sc_get_data(card, 0x0181, buf, 32);
- LOG_TEST_RET(card->ctx, r, "querying serial number failed");
 
- if (r != 8) {
- sc_log(card->ctx, "unexpected response to GET DATA serial number");
- return SC_ERROR_INTERNAL;
+ card->serialnr.len = SC_MAX_SERIALNR;
+ r = sc_parse_ef_gdo(card, card->serialnr.value, &card->serialnr.len, NULL, 0);
+ if (r < 0) {
+ card->serialnr.len = 0;
+ return r;
  }
 
- /* cache serial number */
- memcpy(card->serialnr.value, buf, 8);
- card->serialnr.len = 8;
-
  return SC_SUCCESS;
 }