Add encryption support

src/main/java/net/minestom/server/extras/mojangAuth/MojangCrypt.java

@@ -14,8 +14,7 @@ import java.security.*;
 public final class MojangCrypt {
     private static final Logger LOGGER = LogManager.getLogger();
 
-    @Nullable
+    public static @Nullable KeyPair generateKeyPair() {
-    public static KeyPair generateKeyPair() {
         try {
             KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
             keyGen.initialize(1024);
@@ -27,8 +26,7 @@ public final class MojangCrypt {
         }
     }
 
-    @Nullable
+    public static byte @Nullable [] digestData(String data, PublicKey publicKey, SecretKey secretKey) {
-    public static byte[] digestData(String data, PublicKey publicKey, SecretKey secretKey) {
         try {
             return digestData("SHA-1", data.getBytes("ISO_8859_1"), secretKey.getEncoded(), publicKey.getEncoded());
         } catch (UnsupportedEncodingException e) {
@@ -37,15 +35,12 @@ public final class MojangCrypt {
         }
     }
 
-    @Nullable
+    private static byte @Nullable [] digestData(String algorithm, byte[]... data) {
-    private static byte[] digestData(String algorithm, byte[]... data) {
         try {
             MessageDigest digest = MessageDigest.getInstance(algorithm);
-
             for (byte[] bytes : data) {
                 digest.update(bytes);
             }
-
             return digest.digest();
         } catch (NoSuchAlgorithmException e) {
             MinecraftServer.getExceptionManager().handleException(e);
@@ -67,7 +62,6 @@ public final class MojangCrypt {
         } catch (IllegalBlockSizeException | BadPaddingException var4) {
             MinecraftServer.getExceptionManager().handleException(var4);
         }
-
         LOGGER.error("Cipher data failed!");
         return null;
     }
@@ -80,7 +74,6 @@ public final class MojangCrypt {
         } catch (InvalidKeyException | NoSuchAlgorithmException | NoSuchPaddingException var4) {
             MinecraftServer.getExceptionManager().handleException(var4);
         }
-
         LOGGER.error("Cipher creation failed!");
         return null;
     }

src/main/java/net/minestom/server/network/player/NettyPlayerConnection.java

@@ -5,6 +5,7 @@ import net.minestom.server.MinecraftServer;
 import net.minestom.server.adventure.MinestomAdventure;
 import net.minestom.server.entity.Player;
 import net.minestom.server.entity.PlayerSkin;
+import net.minestom.server.extras.mojangAuth.MojangCrypt;
 import net.minestom.server.network.ConnectionState;
 import net.minestom.server.network.PacketProcessor;
 import net.minestom.server.network.packet.FramedPacket;
@@ -20,7 +21,9 @@ import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import javax.crypto.Cipher;
 import javax.crypto.SecretKey;
+import javax.crypto.ShortBufferException;
 import java.io.IOException;
 import java.net.SocketAddress;
 import java.nio.BufferUnderflowException;
@@ -47,6 +50,8 @@ public class NettyPlayerConnection extends PlayerConnection {
 
     //Could be null. Only used for Mojang Auth
     private byte[] nonce = new byte[4];
+    private Cipher decryptCipher;
+    private Cipher encryptCipher;
 
     // Data from client packets
     private String loginUsername;
@@ -74,6 +79,20 @@ public class NettyPlayerConnection extends PlayerConnection {
 
     public void processPackets(Worker.Context workerContext, PacketProcessor packetProcessor) {
         final var readBuffer = workerContext.readBuffer;
+        // Decrypt data
+        if (encrypted) {
+            final Cipher cipher = decryptCipher;
+            final int remainingBytes = readBuffer.readableBytes();
+            final byte[] bytes = readBuffer.readRemainingBytes();
+            byte[] output = new byte[cipher.getOutputSize(remainingBytes)];
+            try {
+                cipher.update(bytes, 0, remainingBytes, output, 0);
+            } catch (ShortBufferException e) {
+                e.printStackTrace();
+            }
+            readBuffer.clear();
+            readBuffer.writeBytes(output);
+        }
         final int limit = readBuffer.writerOffset();
         // Read all packets
         while (readBuffer.readableBytes() > 0) {
@@ -146,8 +165,9 @@ public class NettyPlayerConnection extends PlayerConnection {
      */
     public void setEncryptionKey(@NotNull SecretKey secretKey) {
         Check.stateCondition(encrypted, "Encryption is already enabled!");
+        this.decryptCipher = MojangCrypt.getCipher(2, secretKey);
+        this.encryptCipher = MojangCrypt.getCipher(1, secretKey);
         this.encrypted = true;
-        // TODO
     }
 
     /**
@@ -221,9 +241,21 @@ public class NettyPlayerConnection extends PlayerConnection {
         synchronized (tickBuffer) {
             if (tickBuffer.readableBytes() == 0) return;
             try {
+                if (encrypted) {
+                    final Cipher cipher = encryptCipher;
+                    // Encrypt data first
+                    final int remainingBytes = tickBuffer.readableBytes();
+                    final byte[] bytes = tickBuffer.readRemainingBytes();
+                    byte[] outTempArray = new byte[cipher.getOutputSize(remainingBytes)];
+                    cipher.update(bytes, 0, remainingBytes, outTempArray);
+                    this.tickBuffer.clear();
+                    this.tickBuffer.writeBytes(outTempArray);
+                }
                 this.tickBuffer.writeChannel(channel);
             } catch (IOException e) {
                 MinecraftServer.getExceptionManager().handleException(e);
+            } catch (ShortBufferException e) {
+                e.printStackTrace();
             } finally {
                 this.tickBuffer.clear();
             }

src/main/java/net/minestom/server/utils/binary/BinaryBuffer.java

@@ -43,7 +43,7 @@ public final class BinaryBuffer {
     public void write(ByteBuffer buffer) {
         final int size = buffer.remaining();
         // TODO jdk 13 put with index
-        asByteBuffer(writerOffset, writerOffset + size).put(buffer);
+        this.nioBuffer.position(writerOffset).put(buffer);
         this.writerOffset += size;
     }
 
@@ -98,13 +98,29 @@ public final class BinaryBuffer {
         return writerOffset - readerOffset;
     }
 
+    public void writeBytes(byte[] bytes) {
+        this.nioBuffer.position(writerOffset).put(bytes);
+        this.writerOffset += bytes.length;
+    }
+
+    public byte[] readBytes(int length) {
+        byte[] bytes = new byte[length];
+        this.nioBuffer.position(readerOffset).get(bytes, 0, length);
+        this.readerOffset += length;
+        return bytes;
+    }
+
+    public byte[] readRemainingBytes() {
+        return readBytes(readableBytes());
+    }
+
     public void clear() {
         this.readerOffset = 0;
         this.writerOffset = 0;
     }
 
     public ByteBuffer asByteBuffer(int reader, int writer) {
-        return nioBuffer.duplicate().position(reader).limit(writer);
+        return nioBuffer.position(reader).slice().limit(writer);
     }
 
     public void writeChannel(WritableByteChannel channel) throws IOException {