func (net *Network) checkTopicRegister(data *topicRegister) (*pong, error) {
	var pongpkt ingressPacket
	if err := decodePacket(data.Pong, &pongpkt); err != nil {
		return nil, err
	}
	if pongpkt.ev != pongPacket {
		return nil, errors.New("is not pong packet")
	}
	if pongpkt.remoteID != net.tab.self.ID {
		return nil, errors.New("not signed by us")
	}
	// check that we previously authorised all topics
	// that the other side is trying to register.
	hash, _, _ := wireHash(data.Topics)
	if hash != pongpkt.data.(*pong).TopicHash {
		return nil, errors.New("topic hash mismatch")
	}
	if data.Idx < 0 || int(data.Idx) >= len(data.Topics) {
		return nil, errors.New("topic index out of range")
	}
	return pongpkt.data.(*pong), nil
}
The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.