Added starter implementation, some rare and weird bugs with messages sometimes failing.

client/src/main/java/nl/andrewl/concord_client/ConcordClient.java

@@ -16,24 +16,27 @@ import nl.andrewl.concord_client.event.handlers.ServerMetaDataHandler;
 import nl.andrewl.concord_client.event.handlers.ServerUsersHandler;
 import nl.andrewl.concord_client.gui.MainWindow;
 import nl.andrewl.concord_client.model.ClientModel;
+import nl.andrewl.concord_core.msg.Encryption;
 import nl.andrewl.concord_core.msg.Message;
 import nl.andrewl.concord_core.msg.Serializer;
+import nl.andrewl.concord_core.msg.types.Error;
 import nl.andrewl.concord_core.msg.types.*;
 
-import java.io.DataInputStream;
-import java.io.DataOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
 import java.net.Socket;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.security.GeneralSecurityException;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
 public class ConcordClient implements Runnable {
 	private final Socket socket;
-	private final DataInputStream in;
+	private InputStream in;
-	private final DataOutputStream out;
+	private OutputStream out;
 	private final Serializer serializer;
 
 	@Getter
@@ -46,8 +49,8 @@ public class ConcordClient implements Runnable {
 	public ConcordClient(String host, int port, String nickname, Path tokensFile) throws IOException {
 		this.eventManager = new EventManager(this);
 		this.socket = new Socket(host, port);
-		this.in = new DataInputStream(this.socket.getInputStream());
+		this.in = this.socket.getInputStream();
-		this.out = new DataOutputStream(this.socket.getOutputStream());
+		this.out = this.socket.getOutputStream();
 		this.serializer = new Serializer();
 		this.model = this.initializeConnectionToServer(nickname, tokensFile);
 
@@ -73,6 +76,15 @@ public class ConcordClient implements Runnable {
 	 * messages, or if the server sends an unexpected response.
 	 */
 	private ClientModel initializeConnectionToServer(String nickname, Path tokensFile) throws IOException {
+		try {
+			System.out.println("Initializing end-to-end encryption with the server...");
+			var streams = Encryption.upgrade(this.in, this.out, this.serializer);
+			this.in = streams.first();
+			this.out = streams.second();
+			System.out.println("Successfully established cipher streams.");
+		} catch (GeneralSecurityException e) {
+			throw new IOException(e);
+		}
 		String token = this.getSessionToken(tokensFile);
 		this.serializer.writeMessage(new Identification(nickname, token), this.out);
 		Message reply = this.serializer.readMessage(this.in);
@@ -83,7 +95,7 @@ public class ConcordClient implements Runnable {
 			this.sendMessage(new ChatHistoryRequest(model.getCurrentChannelId(), ""));
 			return model;
 		} else {
-			throw new IOException("Unexpected response from the server after sending identification message.");
+			throw new IOException("Unexpected response from the server after sending identification message: " + reply);
 		}
 	}
 

client/src/main/java/nl/andrewl/concord_client/event/handlers/ChannelMovedHandler.java

@@ -5,6 +5,8 @@ import nl.andrewl.concord_client.event.MessageHandler;
 import nl.andrewl.concord_core.msg.types.ChatHistoryRequest;
 import nl.andrewl.concord_core.msg.types.MoveToChannel;
 
+import java.util.Map;
+
 /**
  * When the client receives a {@link MoveToChannel} message, it means that the
  * server has told the client that it has been moved to the indicated channel.
@@ -15,6 +17,6 @@ public class ChannelMovedHandler implements MessageHandler<MoveToChannel> {
 	@Override
 	public void handle(MoveToChannel msg, ConcordClient client) throws Exception {
 		client.getModel().setCurrentChannel(msg.getId(), msg.getChannelName());
-		client.sendMessage(new ChatHistoryRequest(msg.getId(), ""));
+		client.sendMessage(new ChatHistoryRequest(msg.getId()));
 	}
 }

client/src/main/java/nl/andrewl/concord_client/gui/ChatList.java

@@ -56,7 +56,9 @@ public class ChatList extends AbstractListBox<Chat, ChatList> implements ChatHis
 	public void chatUpdated(ChatHistory history) {
 		this.getTextGUI().getGUIThread().invokeLater(() -> {
 			this.clearItems();
+			System.out.println("Cleared chats");
 			for (var chat : history.getChats()) {
+				System.out.println("Adding chat: " + chat);
 				this.addItem(chat);
 			}
 		});

core/src/main/java/module-info.java

@@ -1,6 +1,7 @@
 module concord_core {
 	requires static lombok;
 
+	exports nl.andrewl.concord_core.util to concord_server, concord_client;
 	exports nl.andrewl.concord_core.msg to concord_server, concord_client;
 	exports nl.andrewl.concord_core.msg.types to concord_server, concord_client;
 }

core/src/main/java/nl/andrewl/concord_core/msg/Encryption.java

@@ -0,0 +1,73 @@
+package nl.andrewl.concord_core.msg;
+
+import nl.andrewl.concord_core.msg.types.KeyData;
+import nl.andrewl.concord_core.util.Pair;
+
+import javax.crypto.Cipher;
+import javax.crypto.CipherInputStream;
+import javax.crypto.CipherOutputStream;
+import javax.crypto.KeyAgreement;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.security.*;
+import java.security.spec.X509EncodedKeySpec;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public class Encryption {
+	public static Pair<CipherInputStream, CipherOutputStream> upgrade(
+			InputStream in,
+			OutputStream out,
+			Serializer serializer
+	) throws GeneralSecurityException, IOException {
+		// Generate our own key pair.
+		KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC");
+		kpg.initialize(256);
+		KeyPair keyPair = kpg.generateKeyPair();
+		byte[] publicKey = keyPair.getPublic().getEncoded();
+		var random = new SecureRandom();
+		byte[] iv = new byte[16];
+		random.nextBytes(iv);
+		byte[] salt = new byte[8];
+		random.nextBytes(salt);
+		// Send our public key and related data to the client, unencrypted.
+		serializer.writeMessage(new KeyData(iv, salt, publicKey), out);
+
+		// Receive and decode client's unencrypted key data.
+		KeyData clientKeyData = (KeyData) serializer.readMessage(in);
+		PublicKey clientPublicKey = KeyFactory.getInstance("EC")
+				.generatePublic(new X509EncodedKeySpec(clientKeyData.getPublicKey()));
+
+		// Compute secret key from client's public key and our private key.
+		KeyAgreement ka = KeyAgreement.getInstance("ECDH");
+		ka.init(keyPair.getPrivate());
+		ka.doPhase(clientPublicKey, true);
+		byte[] secretKey = computeSecretKey(ka.generateSecret(), publicKey, clientKeyData.getPublicKey());
+
+		// Initialize cipher streams.
+		Cipher writeCipher = Cipher.getInstance("AES/CFB8/NoPadding");
+		Cipher readCipher = Cipher.getInstance("AES/CFB8/NoPadding");
+		Key cipherKey = new SecretKeySpec(secretKey, "AES");
+		writeCipher.init(Cipher.ENCRYPT_MODE, cipherKey, new IvParameterSpec(iv));
+		readCipher.init(Cipher.DECRYPT_MODE, cipherKey, new IvParameterSpec(clientKeyData.getIv()));
+		return new Pair<>(
+				new CipherInputStream(in, readCipher),
+				new CipherOutputStream(out, writeCipher)
+		);
+	}
+
+	private static byte[] computeSecretKey(byte[] sharedSecret, byte[] pk1, byte[] pk2) throws NoSuchAlgorithmException {
+		MessageDigest hash = MessageDigest.getInstance("SHA-256");
+		hash.update(sharedSecret);
+		List<ByteBuffer> keys = Arrays.asList(ByteBuffer.wrap(pk1), ByteBuffer.wrap(pk2));
+		Collections.sort(keys);
+		hash.update(keys.get(0));
+		hash.update(keys.get(1));
+		return hash.digest();
+	}
+}

core/src/main/java/nl/andrewl/concord_core/msg/MessageUtils.java

@@ -15,6 +15,14 @@ import java.util.UUID;
 public class MessageUtils {
 	public static final int UUID_BYTES = 2 * Long.BYTES;
 
+	public static final char MIN_HIGH_SURROGATE = '\uD800';
+	public static final char MAX_HIGH_SURROGATE = '\uDBFF';
+	public static final char MIN_LOW_SURROGATE = '\uDC00';
+	public static final char MAX_LOW_SURROGATE = '\uDFFF';
+	public static final int MIN_SUPPLEMENTARY_CODE_POINT = 0x010000;
+	private static final int SUR_CALC = (MIN_SUPPLEMENTARY_CODE_POINT - (MIN_HIGH_SURROGATE << 10)) - MIN_LOW_SURROGATE;
+
+
 	/**
 	 * Gets the number of bytes that the given string will occupy when it is
 	 * serialized.
@@ -23,6 +31,53 @@ public class MessageUtils {
 	 */
 	public static int getByteSize(String s) {
 		return Integer.BYTES + (s == null ? 0 : s.getBytes(StandardCharsets.UTF_8).length);
+//		int length = s.length();
+//		int i = 0;
+//		int counter = 0;
+//
+//		char c;
+//		while (i < length && (c = s.charAt(i)) < '\u0080') {
+//			// ascii fast loop;
+//			counter++;
+//			i++;
+//		}
+//
+//		while (i < length) {
+//			c = s.charAt(i++);
+//			if (c < 0x80) {
+//				counter++;
+//			} else if (c < 0x800) {
+//				counter += 2;
+//			} else if (Character.isSurrogate(c)) {
+//				int uc = -1;
+//				char c2;
+//				if (isHighSurrogate(c) && i < length && isLowSurrogate(c2 = s.charAt(i))) {
+//					uc = toCodePoint(c, c2);
+//				}
+//				if (uc < 0) {
+//
+//				} else {
+//					counter += 4;
+//					i++;  // 2 chars
+//				}
+//			} else {
+//				// 3 bytes, 16 bits
+//				counter += 3;
+//			}
+//		}
+//
+//		return Integer.BYTES + counter;
+	}
+	public static boolean isHighSurrogate(char ch) {
+		return ch >= MIN_HIGH_SURROGATE && ch < (MAX_HIGH_SURROGATE + 1);
+	}
+
+	public static boolean isLowSurrogate(char ch) {
+		return ch >= MIN_LOW_SURROGATE && ch < (MAX_LOW_SURROGATE + 1);
+	}
+
+	public static int toCodePoint(int high, int low) {
+		return ((high << 10) + low) + SUR_CALC;
 	}
 
 	/**
@@ -54,6 +109,7 @@ public class MessageUtils {
 	public static String readString(DataInputStream i) throws IOException {
 		int length = i.readInt();
 		if (length == -1) return null;
+		if (length == 0) return "";
 		byte[] data = new byte[length];
 		int read = i.read(data);
 		if (read != length) throw new IOException("Not all bytes of a string of length " + length + " could be read.");
@@ -105,11 +161,13 @@ public class MessageUtils {
 		o.writeInt(items.size());
 		for (var i : items) {
 			i.write(o);
+			System.out.println("Wrote " + i);
 		}
 	}
 
 	public static <T extends Message> List<T> readList(Class<T> type, DataInputStream i) throws IOException {
 		int size = i.readInt();
+		System.out.println("Read a size of " + size + " items of type " + type.getSimpleName());
 		try {
 			var constructor = type.getConstructor();
 			List<T> items = new ArrayList<>(size);
@@ -117,6 +175,7 @@ public class MessageUtils {
 				var item = constructor.newInstance();
 				item.read(i);
 				items.add(item);
+				System.out.println("Read item " + (k+1) + " of " + size + ": " + item);
 			}
 			return items;
 		} catch (ReflectiveOperationException e) {

core/src/main/java/nl/andrewl/concord_core/msg/Serializer.java

@@ -39,6 +39,7 @@ public class Serializer {
 		registerType(8, ServerMetaData.class);
 		registerType(9, Error.class);
 		registerType(10, CreateThread.class);
+		registerType(11, KeyData.class);
 	}
 
 	/**

core/src/main/java/nl/andrewl/concord_core/msg/types/Chat.java

@@ -42,7 +42,7 @@ public class Chat implements Message {
 
 	@Override
 	public int getByteCount() {
-		return UUID_BYTES + Long.BYTES + getByteSize(this.senderNickname) + getByteSize(this.message);
+		return 2 * UUID_BYTES + Long.BYTES + getByteSize(this.senderNickname) + getByteSize(this.message);
 	}
 
 	@Override
@@ -61,6 +61,7 @@ public class Chat implements Message {
 		this.senderNickname = readString(i);
 		this.timestamp = i.readLong();
 		this.message = readString(i);
+		System.out.println("Read chat: " + this);
 	}
 
 	@Override

core/src/main/java/nl/andrewl/concord_core/msg/types/ChatHistoryRequest.java

@@ -58,6 +58,10 @@ public class ChatHistoryRequest implements Message {
 	private UUID channelId;
 	private String query;
 
+	public ChatHistoryRequest(UUID channelId) {
+		this(channelId, "");
+	}
+
 	public ChatHistoryRequest(UUID channelId, Map<String, String> params) {
 		this.channelId = channelId;
 		this.query = params.entrySet().stream()
@@ -87,7 +91,7 @@ public class ChatHistoryRequest implements Message {
 
 	@Override
 	public int getByteCount() {
-		return UUID_BYTES + Integer.BYTES + getByteSize(this.query);
+		return UUID_BYTES + getByteSize(this.query);
 	}
 
 	@Override

core/src/main/java/nl/andrewl/concord_core/msg/types/ChatHistoryResponse.java

@@ -4,7 +4,6 @@ import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.NoArgsConstructor;
 import nl.andrewl.concord_core.msg.Message;
-import nl.andrewl.concord_core.msg.MessageUtils;
 
 import java.io.DataInputStream;
 import java.io.DataOutputStream;
@@ -12,6 +11,8 @@ import java.io.IOException;
 import java.util.List;
 import java.util.UUID;
 
+import static nl.andrewl.concord_core.msg.MessageUtils.*;
+
 /**
  * The response that a server sends to a {@link ChatHistoryRequest}. The list of
  * messages is ordered by timestamp, with the newest messages appearing first.
@@ -25,32 +26,19 @@ public class ChatHistoryResponse implements Message {
 
 	@Override
 	public int getByteCount() {
-		int count = Long.BYTES + Integer.BYTES;
+		return UUID_BYTES + getByteSize(messages);
-		for (var message : this.messages) {
-			count += message.getByteCount();
-		}
-		return count;
 	}
 
 	@Override
 	public void write(DataOutputStream o) throws IOException {
-		MessageUtils.writeUUID(this.channelId, o);
+		writeUUID(this.channelId, o);
-		o.writeInt(messages.size());
+		writeList(this.messages, o);
-		for (var message : this.messages) {
-			message.write(o);
-		}
 	}
 
 	@Override
 	public void read(DataInputStream i) throws IOException {
-		this.channelId = MessageUtils.readUUID(i);
+		this.channelId = readUUID(i);
-		int messageCount = i.readInt();
+		System.out.println("Reading list of chats...");
-		Chat[] messages = new Chat[messageCount];
+		this.messages = readList(Chat.class, i);
-		for (int k = 0; k < messageCount; k++) {
-			Chat c = new Chat();
-			c.read(i);
-			messages[k] = c;
-		}
-		this.messages = List.of(messages);
 	}
 }

core/src/main/java/nl/andrewl/concord_core/msg/types/KeyData.java

@@ -0,0 +1,52 @@
+package nl.andrewl.concord_core.msg.types;
+
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import nl.andrewl.concord_core.msg.Message;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+/**
+ * This message is sent as the first message from both the server and the client
+ * to establish an end-to-end encryption via a key exchange.
+ */
+@Getter
+@NoArgsConstructor
+public class KeyData implements Message {
+	private byte[] iv;
+	private byte[] salt;
+	private byte[] publicKey;
+
+	public KeyData(byte[] iv, byte[] salt, byte[] publicKey) {
+		this.iv = iv;
+		this.salt = salt;
+		this.publicKey = publicKey;
+	}
+
+	@Override
+	public int getByteCount() {
+		return Integer.BYTES * 3 + iv.length + salt.length + publicKey.length;
+	}
+
+	@Override
+	public void write(DataOutputStream o) throws IOException {
+		o.writeInt(iv.length);
+		o.write(iv);
+		o.writeInt(salt.length);
+		o.write(salt);
+		o.writeInt(publicKey.length);
+		o.write(publicKey);
+	}
+
+	@Override
+	public void read(DataInputStream i) throws IOException {
+		int ivLength = i.readInt();
+		this.iv = i.readNBytes(ivLength);
+		int saltLength = i.readInt();
+		this.salt = i.readNBytes(saltLength);
+		int publicKeyLength = i.readInt();
+		this.publicKey = i.readNBytes(publicKeyLength);
+	}
+}

core/src/main/java/nl/andrewl/concord_core/util/Pair.java

@@ -0,0 +1,3 @@
+package nl.andrewl.concord_core.util;
+
+public record Pair<A, B>(A first, B second) {}

server/src/main/java/nl/andrewl/concord_server/client/ClientThread.java

@@ -2,15 +2,16 @@ package nl.andrewl.concord_server.client;
 
 import lombok.Getter;
 import lombok.Setter;
+import nl.andrewl.concord_core.msg.Encryption;
 import nl.andrewl.concord_core.msg.Message;
 import nl.andrewl.concord_core.msg.types.Identification;
 import nl.andrewl.concord_core.msg.types.UserData;
-import nl.andrewl.concord_server.channel.Channel;
 import nl.andrewl.concord_server.ConcordServer;
+import nl.andrewl.concord_server.channel.Channel;
 
-import java.io.DataInputStream;
-import java.io.DataOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
 import java.net.Socket;
 import java.util.UUID;
 
@@ -20,8 +21,8 @@ import java.util.UUID;
  */
 public class ClientThread extends Thread {
 	private final Socket socket;
-	private final DataInputStream in;
+	private InputStream in;
-	private final DataOutputStream out;
+	private OutputStream out;
 
 	private final ConcordServer server;
 
@@ -48,8 +49,8 @@ public class ClientThread extends Thread {
 	public ClientThread(Socket socket, ConcordServer server) throws IOException {
 		this.socket = socket;
 		this.server = server;
-		this.in = new DataInputStream(socket.getInputStream());
+		this.in = socket.getInputStream();
-		this.out = new DataOutputStream(socket.getOutputStream());
+		this.out = socket.getOutputStream();
 	}
 
 	/**
@@ -76,6 +77,7 @@ public class ClientThread extends Thread {
 			this.out.flush();
 		} catch (IOException e) {
 			e.printStackTrace();
+			System.err.printf("Could not send to client %s(%s): %s", this.clientId, this.clientNickname, e.getMessage());
 		}
 	}
 
@@ -104,6 +106,7 @@ public class ClientThread extends Thread {
 		while (this.running) {
 			try {
 				var msg = this.server.getSerializer().readMessage(this.in);
+				System.out.println("Received " + msg.getClass().getSimpleName() + " from " + this.clientNickname);
 				this.server.getEventManager().handle(msg, this);
 			} catch (IOException e) {
 				this.running = false;
@@ -131,6 +134,16 @@ public class ClientThread extends Thread {
 	 */
 	private boolean identifyClient() {
 		int attempts = 0;
+		try {
+			System.out.println("Initializing end-to-end encryption with the client...");
+			var streams = Encryption.upgrade(this.in, this.out, server.getSerializer());
+			this.in = streams.first();
+			this.out = streams.second();
+			System.out.println("Successfully established cipher streams.");
+		} catch (Exception e) {
+			e.printStackTrace();
+			return false;
+		}
 		while (attempts < 5) {
 			try {
 				var msg = this.server.getSerializer().readMessage(this.in);

server/src/main/java/nl/andrewl/concord_server/event/ChatHistoryRequestHandler.java

@@ -59,7 +59,7 @@ public class ChatHistoryRequestHandler implements MessageHandler<ChatHistoryRequ
 	}
 
 	private ChatHistoryResponse getResponse(Channel channel, long count, Long from, Long to) {
-		var col = channel.getServer().getDb().getCollection("channel-" + channel.getId());
+		var col = channel.getMessageCollection();
 		Cursor cursor;
 		FindOptions options = FindOptions.sort("timestamp", SortOrder.Descending).thenLimit(0, (int) count);
 		List<Filter> filters = new ArrayList<>(2);
@@ -74,12 +74,13 @@ public class ChatHistoryRequestHandler implements MessageHandler<ChatHistoryRequ
 		} else {
 			cursor = col.find(Filters.and(filters.toArray(new Filter[0])), options);
 		}
+		System.out.println("Found " + cursor.size() + " chats");
 
 		List<Chat> chats = new ArrayList<>((int) count);
 		for (Document doc : cursor) {
 			chats.add(this.read(doc));
 		}
-		col.close();
+		System.out.println(chats);
 		chats.sort(Comparator.comparingLong(Chat::getTimestamp));
 		return new ChatHistoryResponse(channel.getId(), chats);
 	}