openpgp: Fix retry counter of encryption PIN in SC_PIN_CMD_GET_INFO emulation for card supporting OpenPGP card spec v2.0 and later

The meaning of byte 6 of DO C4 has changed from the retry counter of the encryption
PIN (CHV2) to that of resetting code since OpenPGP card spec v2.0, and PW1 now serves
as both the signature and encryption PIN. Map PIN reference from 82 to 81 to correct
retry counter of encryption PIN for these cards.

Author: MkfsSion

src/libopensc/card-openpgp.c

@@ -2468,6 +2468,14 @@ pgp_pin_cmd(sc_card_t *card, struct sc_pin_cmd_data *data, int *tries_left)
 			LOG_TEST_RET(card->ctx, SC_ERROR_OBJECT_NOT_VALID,
 				"CHV status bytes have unexpected length");
 
+		/* The definition of fields of DO C4 changed between OpenPGP
+		 * card specification v1.1 and v2.0. There is no longer a separate
+		 * CHV2 retry counter but only one retry counter for both PW1 mode 1
+		 * and mode 2 at byte 5 (count from 1) of the DO.
+		 */
+		if (priv->bcd_version >= OPENPGP_CARD_2_0 && data->pin_reference == 0x82)
+			data->pin_reference = 0x81;
+
 		data->pin1.tries_left = c4data[3 + (data->pin_reference & 0x0F)];
 		data->pin1.max_tries = 3;
 		data->pin1.logged_in = SC_PIN_STATE_UNKNOWN;