some times RecalculateChecksum panic error: slice bounds out of range [36:0]goroutine 166

[introspection3]

func (data *Packet) RecalculateChecksum() {
	const (
		IPProtocolTCP = 6
		IPProtocolUDP = 17
	)

	if data.IsIPv6 {
		// TODO
	} else {
		ipHeaderLen := int(data.Packet[0]&0x0f) << 2
		copy(data.Packet[ipv4offsetChecksum:], []byte{0, 0})
		ipChecksum := checksumIPv4Header(data.Packet[:ipHeaderLen])
		binary.BigEndian.PutUint16(data.Packet[ipv4offsetChecksum:], ipChecksum)

		switch protocol := data.Packet[9]; protocol {
		case IPProtocolTCP:
			tcpOffsetChecksum := ipHeaderLen + 16
			copy(data.Packet[tcpOffsetChecksum:], []byte{0, 0})
			checksum := checksumIPv4TCPUDP(data.Packet[ipHeaderLen:], uint32(protocol), data.Src, data.Dst)
			binary.BigEndian.PutUint16(data.Packet[tcpOffsetChecksum:], checksum)
		case IPProtocolUDP:
			udpOffsetChecksum := ipHeaderLen + 6
			copy(data.Packet[udpOffsetChecksum:], []byte{0, 0})
			checksum := checksumIPv4TCPUDP(data.Packet[ipHeaderLen:], uint32(protocol), data.Src, data.Dst)
			binary.BigEndian.PutUint16(data.Packet[udpOffsetChecksum:], checksum)
		}
	}
}

(*Packet).RecalculateChecksum(0x40016ae008)
error: slice bounds out of range [36:0]
binary.BigEndian.PutUint16(data.Packet[tcpOffsetChecksum:], checksum) !!!!!!!!!!!

[pymq]

Hi @introspection3, thanks for the report. Do you know how to reproduce it? Maybe you know what protocols you are using with VPN? What version of awl and OS platform are you using?