Port Knocking & Encrypted Login

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Chuck Norris approva quest'applicazione :)

Codice lato server

/**
 * @PkServer
 *
 *
 * @author - Michele Nacucchi e Francesco Sportelli
 */
 
import java.io.IOException;
import java.net.*;
import java.util.Hashtable;
 
public class Server {
    static Hashtable<String, String > userTable=new Hashtable<String, String>();
 
public static void main (String args[]) throws IOException {
 
    caricaUserTable();
 
    PackageSelector filtro = new PackageSelector();
    filtro.start();
 
    ServerSocket serversocket = new ServerSocket(2009);
    Socket s = null;
    while (true) {
        s = serversocket.accept();
 
        try {
            if (filtro.getIPTable().get(s.getInetAddress().toString().substring(1))!=3) {
                s.close();
                System.out.println("Connessione in ingresso nn autorizzata");
            }
            else{
                System.out.println("Connessione in ingresso autorizzata");
                new ConnectionManager(s,filtro.getIPTable(),userTable).start();
            }
        } catch (NullPointerException e) {
        s.close();
        System.out.println("Connessione in ingresso non riuscita");
        }
 
    }    
}
 
private static void caricaUserTable() {
    userTable.put("ciccio", "pass1");
    userTable.put("miki", "pass2");
    userTable.put("ndm", "pass3");
}
}
 
//Classe PackageSelector
import java.io.IOException;
import java.util.Hashtable;
import java.util.Scanner;
import jpcap.*;
import jpcap.packet.Packet;
 
public class PackageSelector extends Thread{
    private static Hashtable<String, Integer> IPTable;
    private JpcapCaptor captor = null;
    public Hashtable<String, Integer> getIPTable() {
        return IPTable;
    }
    public PackageSelector() throws IOException {
        IPTable=new Hashtable<String, Integer>();
        NetworkInterface[] devices = JpcapCaptor.getDeviceList();
 
                //per ogni interfaccia
                for (int i = 0; i < devices.length; i++) {
                  //stampa la descrizione
                  System.out.println(i+": "+devices[i].name + "(" + devices[i].description+")");
 
                  //descrizione datalink
                  System.out.println(" datalink: "+devices[i].datalink_name + "(" + devices[i].datalink_description+")");
 
                  //stampa mac address
                  System.out.print(" MAC address:");
                  for (byte b : devices[i].mac_address)
                    System.out.print(Integer.toHexString(b&0xff) + ":");
                  System.out.println();
 
                  //stampa IP,subnet mask,address
                  for (NetworkInterfaceAddress a : devices[i].addresses)
                    System.out.println(" address:"+a.address + " " + a.subnet + " "+ a.broadcast);
                }
        Scanner in = new Scanner(System.in);
        System.out.println("Seleziona interfaccia di rete");
        int index= in.nextInt();
        captor=JpcapCaptor.openDevice(devices[index], 65535, false, 20);
        System.out.println("Hai scelto di usare l'interfaccia:");
        System.out.println(devices[index].name);
 
        captor.setFilter("tcp dst port 3100 or 3500 or 3900", true);
    }
    public void run() {
        captor.loopPacket(-1, new PacketPrinter(this));
 
    }
 
}
 
//Classe PacketPrinter
 
import java.util.Hashtable;
import jpcap.PacketReceiver;
import jpcap.packet.Packet;
 
public class PacketPrinter implements PacketReceiver {
    Hashtable<String,Integer> IPTable=null;
    public PacketPrinter(PackageSelector obj){
        this.IPTable=obj.getIPTable();
    }
 
    public void receivePacket(Packet pk) {
        int port = getPort(pk.toString());
        String IP = getIP(pk.toString());
        System.out.println(IP+"ha bussato sulla porta:"+port);
        try {
                switch (port) {
                case 3100:
                    IPTable.put(IP,1);
                    break;
                case 3500:
                    if(IPTable.get(IP)==1) IPTable.put(IP,2);//prime due porte "bussate" in sequenza
                    break;
                case 3900:
                    if(IPTable.get(IP)==2) IPTable.put(IP,3);//sequenza corretta!
                    break;
                default:
                    IPTable.remove(IP);
                    break;
                }            
                System.out.println("val: "+IPTable.get(IP));
 
        } catch (NullPointerException e) {
        }
 
    }
 
    static String getIP(String packet){
          String IP = packet;
          IP = IP.substring(IP.indexOf('/')+1);
          IP = IP.substring(0,IP.indexOf('-'));
          return IP;
      }
 
      static int getPort(String packet){
          String port = packet;
          port = port.substring(port.indexOf('>')+1);
          port = port.substring(port.indexOf('>')+2);
          port = port.substring(0,port.indexOf(' '));
          return Integer.parseInt(port);
      }
 
}
 
//Classe ConnectionManager
 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Date;
import java.util.Hashtable;
 
public class ConnectionManager extends Thread{
    private Socket s = null;
    private BufferedReader fromSocket = null;
    private PrintWriter toSocket = null;
    private Hashtable<String, Integer> IPTable = null;
    private Hashtable<String, String> userTable = null;
 
    private String userConnected;
    private String userPassword;
 
    public ConnectionManager(Socket s,Hashtable<String, Integer> IPTable, Hashtable<String, String> userTable) throws IOException{
        this.s=s;
        this.IPTable=IPTable;
        this.userTable=userTable;
    }
    public void run(){
        //Avviare la procedura di login per i client correttamente autenticati
        try {
        fromSocket = new BufferedReader(new InputStreamReader(s.getInputStream()));
        toSocket = new PrintWriter(s.getOutputStream(),true);
        send("Connessione avvenuta con successo");
        int i=0;
        String user;
        String pass;
        do{
            String key=keyTemp();
            send(key);
            send("Inserire USER:");            
            user = Codifica.decripta(waitAndReceive(), key);
            System.out.println(user);
 
            key=keyTemp();
            send(key);
            send("Inserire PASSWORD:");
            pass = Codifica.decripta(waitAndReceive(), key);
            System.out.println(pass);
 
            if (pass.equals(userTable.get(user))){
                send("Utente AUTENTICATO");
                i=4;
            }
            else{
                i++;
                send("Autenticazione FALLITA! Tentativi rimasti:"+(3-i));    
            }
        }while(i<3);        
        if(i<4){
            send("Tentativi esauriti rieffettuare la procedura di autenticazione");
            IPTable.remove(s.getInetAddress().toString().substring(1));
            s.close();
            return;
        }
        //Il client ha effettuato con successo sia la procedura di PortKnocking, sia il LogIn.
        send("Benvenuto "+user+". Sei stato autenticato con successo!");
        userConnected=user;
        userPassword=pass;
        IPTable.remove(s.getInetAddress().toString().substring(1));
 
        //Comunicazione tra Client e Server post autenticazione...
 
        } catch (IOException e) {
            try {
                send("Tentativi esauriti rieffettuare la procedura di autenticazione");
                IPTable.remove(s.getInetAddress().toString().substring(1));
                s.close();
                return;            
            } catch (IOException e1) {        e1.printStackTrace();    }            
        }
    }
 
    private String keyTemp() {        
        Date d=new Date();
        return new Integer((int)(d.getTime()*Math.random()%100*1024)).toString();
    }
 
    private  String waitAndReceive() throws IOException {
        String str;
        while ((str=fromSocket.readLine())==null);
        return str;
    }
 
    private void send(String str) {
        toSocket.println(str);
        toSocket.flush();
    }
}
 
//Classe Codifica
 
public class Codifica {
    private Codifica() {
    }
 
    public static String cripta(String str,String chiave) {
        StringBuffer s = new StringBuffer(str);
        int len = s.length();
        int i,uni;
        int key = Integer.parseInt(chiave)/1024;
        for (i=0;i<len;i++) {
            char c = s.charAt(i); //Il char i-esimo
            uni = (int)c; //Estrae il codice unicode
            c = (char)((len + uni)+ key+i); // Lo codifica
            s.setCharAt(i, c); //L'i-esimo carattere convertito
        }
        return s.toString();
    }
 
    public static String decripta(String str,String chiave) {
        StringBuffer s = new StringBuffer(str);
        int len = s.length();
        int i;
        int uni;
        int key = Integer.parseInt(chiave)/1024;
        for (i=0;i<len;i++) {
            char c = s.charAt(i); //Il char i-esimo
            uni = (int)c; //Estrae il carattere unicode
            c = (char)((uni-len)- key-i); // Lo codifica
            s.setCharAt(i, c); //L'i-esimo carattere convertito
        }    
        return s.toString();
    }
 
}

Codice lato client

/**
 * @PkClient
 *
 *
 * @author - Michele Nacucchi e Francesco Sportelli
 */
 
import java.io.BufferedInputStream;
import java.util.Scanner;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
 
public class Client {
 
    private static BufferedReader fromSocket=null;
    private static PrintWriter toSocket=null;
 
    public static void main(String[] args){
        Socket s=null;
        Scanner in = new Scanner(System.in);
        System.out.println("Inserisci l'indirizzo IP del Server:");
        String dest = in.nextLine();
        int port;
        do{
            System.out.println("Inserisci un numero di porta");
            port = in.nextInt();
            if(port==2009)break;//porta aperta per accedere al servizio
            try {    s=new Socket(dest,port);    } 
            catch (UnknownHostException e) {} 
            catch (IOException e) {}
        }while(port!=2009);
 
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e1) {    e1.printStackTrace();}
        try {    s=new Socket(dest,2009);    
        String str;
        fromSocket=new BufferedReader(new InputStreamReader(s.getInputStream()));
        toSocket=new PrintWriter(s.getOutputStream(),true);        
        BufferedReader userIn=new BufferedReader(new InputStreamReader(System.in));    
        System.out.println(waitAndReceive());
        do{
            //Trasmissione criptata dell'user
            String key=waitAndReceive();
            //System.out.println(key);
            System.out.println(waitAndReceive());
            str=userIn.readLine();
            send(Codifica.cripta(str, key));
 
            //Trasmissione criptata della password
            key=waitAndReceive();
            //System.out.println(key);
            System.out.println(waitAndReceive());
            str=userIn.readLine();
            send(Codifica.cripta(str, key));
 
            //Esito da Server
            str=waitAndReceive();
            System.out.println(str);            
        }while(!str.equals("Utente AUTENTICATO")||!str.equals("Tentativi esauriti rieffettuare la procedura di autenticazione"));
        } 
        catch (UnknownHostException e) {    e.printStackTrace();        } 
        catch (IOException e) {    e.printStackTrace();        }
    }
 
    private static String waitAndReceive() throws IOException {
        String str;
        while ((str=fromSocket.readLine())==null);
        return str;
    }
 
    private static void send(String str) {
        toSocket.println(str);
        toSocket.flush();
    }
 
}
 
//Classe Codifica
 
public class Codifica {
    private Codifica() {
    }
 
    public static String cripta(String str,String chiave) {
        StringBuffer s = new StringBuffer(str);
        int len = s.length();
        int i,uni;
        int key = Integer.parseInt(chiave)/1024;
        for (i=0;i<len;i++) {
            char c = s.charAt(i); //Il char i-esimo
            uni = (int)c; //Estrae il codice unicode
            c = (char)((len + uni)+ key+i); // Lo codifica
            s.setCharAt(i, c); //L'i-esimo carattere convertito
        }
        return s.toString();
    }
 
    public static String decripta(String str,String chiave) {
        StringBuffer s = new StringBuffer(str);
        int len = s.length();
        int i;
        int uni;
        int key = Integer.parseInt(chiave)/1024;
        for (i=0;i<len;i++) {
            char c = s.charAt(i); //Il char i-esimo
            uni = (int)c; //Estrae il carattere unicode
            c = (char)((uni-len)- key-i); // Lo codifica
            s.setCharAt(i, c); //L'i-esimo carattere convertito
        }    
        return s.toString();
    }
 
}