trezor-firmware/firmware/fsm_msg_coin.h

void fsm_msgGetPublicKey(GetPublicKey *msg)
{
	RESP_INIT(PublicKey);

	CHECK_INITIALIZED

	CHECK_PIN

	const CoinInfo *coin = fsm_getCoin(msg->has_coin_name, msg->coin_name);
	if (!coin) return;

	const char *curve = coin->curve_name;
	if (msg->has_ecdsa_curve_name) {
		curve = msg->ecdsa_curve_name;
	}
	uint32_t fingerprint;
	HDNode *node = node = fsm_getDerivedNode(curve, msg->address_n, msg->address_n_count, &fingerprint);
	if (!node) return;
	hdnode_fill_public_key(node);

	if (msg->has_show_display && msg->show_display) {
		layoutPublicKey(node->public_key);
		if (!protectButton(ButtonRequest_ButtonRequestType_ButtonRequest_PublicKey, true)) {
			fsm_sendFailure(Failure_FailureType_Failure_ActionCancelled, NULL);
			layoutHome();
			return;
		}
	}

	resp->node.depth = node->depth;
	resp->node.fingerprint = fingerprint;
	resp->node.child_num = node->child_num;
	resp->node.chain_code.size = 32;
	memcpy(resp->node.chain_code.bytes, node->chain_code, 32);
	resp->node.has_private_key = false;
	resp->node.has_public_key = true;
	resp->node.public_key.size = 33;
	memcpy(resp->node.public_key.bytes, node->public_key, 33);
	if (node->public_key[0] == 1) {
		/* ed25519 public key */
		resp->node.public_key.bytes[0] = 0;
	}
	resp->has_xpub = true;
	hdnode_serialize_public(node, fingerprint, coin->xpub_magic, resp->xpub, sizeof(resp->xpub));
	msg_write(MessageType_MessageType_PublicKey, resp);
	layoutHome();
}

void fsm_msgSignTx(SignTx *msg)
{
	CHECK_INITIALIZED

	CHECK_PARAM(msg->inputs_count > 0, _("Transaction must have at least one input"));
	CHECK_PARAM(msg->outputs_count > 0, _("Transaction must have at least one output"));
	CHECK_PARAM(msg->inputs_count + msg->outputs_count >= msg->inputs_count, _("Value overflow"));

	CHECK_PIN

	const CoinInfo *coin = fsm_getCoin(msg->has_coin_name, msg->coin_name);
	if (!coin) return;
	const HDNode *node = fsm_getDerivedNode(coin->curve_name, NULL, 0, NULL);
	if (!node) return;

	signing_init(msg, coin, node);
}

void fsm_msgTxAck(TxAck *msg)
{
	CHECK_PARAM(msg->has_tx, _("No transaction provided"));

	signing_txack(&(msg->tx));
}

static bool path_mismatched(const CoinInfo *coin, const GetAddress *msg)
{
	bool mismatch = false;

	// m : no path
	if (msg->address_n_count == 0) {
		return false;
	}

	// m/44' : BIP44 Legacy
	// m / purpose' / coin_type' / account' / change / address_index
	if (msg->address_n[0] == (0x80000000 + 44)) {
		mismatch |= (msg->script_type != InputScriptType_SPENDADDRESS);
		mismatch |= (msg->address_n_count != 5);
		mismatch |= (msg->address_n[1] != coin->coin_type);
		mismatch |= (msg->address_n[2] & 0x80000000) == 0;
		mismatch |= (msg->address_n[3] & 0x80000000) == 0x80000000;
		mismatch |= (msg->address_n[4] & 0x80000000) == 0x80000000;
		return mismatch;
	}

	// m/45' - BIP45 Copay Abandoned Multisig P2SH
	// m / purpose' / cosigner_index / change / address_index
	if (msg->address_n[0] == (0x80000000 + 45)) {
		mismatch |= (msg->script_type != InputScriptType_SPENDMULTISIG);
		mismatch |= (msg->address_n_count != 4);
		mismatch |= (msg->address_n[1] & 0x80000000) == 0x80000000;
		mismatch |= (msg->address_n[2] & 0x80000000) == 0x80000000;
		mismatch |= (msg->address_n[3] & 0x80000000) == 0x80000000;
		return mismatch;
	}

	// m/48' - BIP48 Copay Multisig P2SH
	// m / purpose' / coin_type' / account' / change / address_index
	if (msg->address_n[0] == (0x80000000 + 48)) {
		mismatch |= (msg->script_type != InputScriptType_SPENDMULTISIG);
		mismatch |= (msg->address_n_count != 5);
		mismatch |= (msg->address_n[1] != coin->coin_type);
		mismatch |= (msg->address_n[2] & 0x80000000) == 0;
		mismatch |= (msg->address_n[3] & 0x80000000) == 0x80000000;
		mismatch |= (msg->address_n[4] & 0x80000000) == 0x80000000;
		return mismatch;
	}

	// m/49' : BIP49 SegWit
	// m / purpose' / coin_type' / account' / change / address_index
	if (msg->address_n[0] == (0x80000000 + 49)) {
		mismatch |= (msg->script_type != InputScriptType_SPENDP2SHWITNESS);
		mismatch |= !coin->has_segwit;
		mismatch |= !coin->has_address_type_p2sh;
		mismatch |= (msg->address_n_count != 5);
		mismatch |= (msg->address_n[1] != coin->coin_type);
		mismatch |= (msg->address_n[2] & 0x80000000) == 0;
		mismatch |= (msg->address_n[3] & 0x80000000) == 0x80000000;
		mismatch |= (msg->address_n[4] & 0x80000000) == 0x80000000;
		return mismatch;
	}

	// m/84' : BIP84 Native SegWit
	// m / purpose' / coin_type' / account' / change / address_index
	if (msg->address_n[0] == (0x80000000 + 84)) {
		mismatch |= (msg->script_type != InputScriptType_SPENDWITNESS);
		mismatch |= !coin->has_segwit;
		mismatch |= !coin->bech32_prefix;
		mismatch |= (msg->address_n_count != 5);
		mismatch |= (msg->address_n[1] != coin->coin_type);
		mismatch |= (msg->address_n[2] & 0x80000000) == 0;
		mismatch |= (msg->address_n[3] & 0x80000000) == 0x80000000;
		mismatch |= (msg->address_n[4] & 0x80000000) == 0x80000000;
		return mismatch;
	}

	return false;
}

void fsm_msgGetAddress(GetAddress *msg)
{
	RESP_INIT(Address);

	CHECK_INITIALIZED

	CHECK_PIN

	const CoinInfo *coin = fsm_getCoin(msg->has_coin_name, msg->coin_name);
	if (!coin) return;
	HDNode *node = fsm_getDerivedNode(coin->curve_name, msg->address_n, msg->address_n_count, NULL);
	if (!node) return;
	hdnode_fill_public_key(node);

	char address[MAX_ADDR_SIZE];
	if (msg->has_multisig) {  // use progress bar only for multisig
		layoutProgress(_("Computing address"), 0);
	}
	if (!compute_address(coin, msg->script_type, node, msg->has_multisig, &msg->multisig, address)) {
		fsm_sendFailure(Failure_FailureType_Failure_DataError, _("Can't encode address"));
		layoutHome();
		return;
	}

	if (msg->has_show_display && msg->show_display) {
		char desc[20];
		if (msg->has_multisig) {
			strlcpy(desc, "Multisig __ of __:", sizeof(desc));
			const uint32_t m = msg->multisig.m;
			const uint32_t n = msg->multisig.pubkeys_count;
			desc[9] = (m < 10) ? ' ': ('0' + (m / 10));
			desc[10] = '0' + (m % 10);
			desc[15] = (n < 10) ? ' ': ('0' + (n / 10));
			desc[16] = '0' + (n % 10);
		} else {
			strlcpy(desc, _("Address:"), sizeof(desc));
		}

		bool mismatch = path_mismatched(coin, msg);

		if (mismatch) {
			layoutDialogSwipe(&bmp_icon_warning, _("Abort"), _("Continue"), NULL, _("Wrong address path"), _("for selected coin."), NULL, _("Continue at your"), _("own risk!"), NULL);
			if (!protectButton(ButtonRequest_ButtonRequestType_ButtonRequest_Other, false)) {
				fsm_sendFailure(Failure_FailureType_Failure_ActionCancelled, NULL);
				layoutHome();
				return;
			}
		}

		bool is_cashaddr = coin->cashaddr_prefix != NULL;
		bool is_bech32 = msg->script_type == InputScriptType_SPENDWITNESS;
		if (!fsm_layoutAddress(address, desc, is_cashaddr || is_bech32, is_cashaddr ? strlen(coin->cashaddr_prefix) + 1 : 0, msg->address_n, msg->address_n_count)) {
			return;
		}
	}

	strlcpy(resp->address, address, sizeof(resp->address));
	msg_write(MessageType_MessageType_Address, resp);
	layoutHome();
}

void fsm_msgSignMessage(SignMessage *msg)
{
	RESP_INIT(MessageSignature);

	CHECK_INITIALIZED

	layoutSignMessage(msg->message.bytes, msg->message.size);
	if (!protectButton(ButtonRequest_ButtonRequestType_ButtonRequest_ProtectCall, false)) {
		fsm_sendFailure(Failure_FailureType_Failure_ActionCancelled, NULL);
		layoutHome();
		return;
	}

	CHECK_PIN

	const CoinInfo *coin = fsm_getCoin(msg->has_coin_name, msg->coin_name);
	if (!coin) return;
	HDNode *node = fsm_getDerivedNode(coin->curve_name, msg->address_n, msg->address_n_count, NULL);
	if (!node) return;

	layoutProgressSwipe(_("Signing"), 0);
	if (cryptoMessageSign(coin, node, msg->script_type, msg->message.bytes, msg->message.size, resp->signature.bytes) == 0) {
		resp->has_address = true;
		hdnode_fill_public_key(node);
		if (!compute_address(coin, msg->script_type, node, false, NULL, resp->address)) {
			fsm_sendFailure(Failure_FailureType_Failure_ProcessError, _("Error computing address"));
			layoutHome();
			return;
		}
		resp->has_signature = true;
		resp->signature.size = 65;
		msg_write(MessageType_MessageType_MessageSignature, resp);
	} else {
		fsm_sendFailure(Failure_FailureType_Failure_ProcessError, _("Error signing message"));
	}
	layoutHome();
}

void fsm_msgVerifyMessage(VerifyMessage *msg)
{
	CHECK_PARAM(msg->has_address, _("No address provided"));
	CHECK_PARAM(msg->has_message, _("No message provided"));

	const CoinInfo *coin = fsm_getCoin(msg->has_coin_name, msg->coin_name);
	if (!coin) return;
	layoutProgressSwipe(_("Verifying"), 0);
	if (msg->signature.size == 65 && cryptoMessageVerify(coin, msg->message.bytes, msg->message.size, msg->address, msg->signature.bytes) == 0) {
		layoutVerifyAddress(msg->address);
		if (!protectButton(ButtonRequest_ButtonRequestType_ButtonRequest_Other, false)) {
			fsm_sendFailure(Failure_FailureType_Failure_ActionCancelled, NULL);
			layoutHome();
			return;
		}
		layoutVerifyMessage(msg->message.bytes, msg->message.size);
		if (!protectButton(ButtonRequest_ButtonRequestType_ButtonRequest_Other, false)) {
			fsm_sendFailure(Failure_FailureType_Failure_ActionCancelled, NULL);
			layoutHome();
			return;
		}
		fsm_sendSuccess(_("Message verified"));
	} else {
		fsm_sendFailure(Failure_FailureType_Failure_DataError, _("Invalid signature"));
	}
	layoutHome();
}