Switch Floodgate encryption from RSA to AES

common/src/main/java/org/geysermc/floodgate/crypto/AesCipher.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2019-2020 GeyserMC. http://geysermc.org
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in
+ *  all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ *  THE SOFTWARE.
+ *
+ *  @author GeyserMC
+ *  @link https://github.com/GeyserMC/Floodgate
+ *
+ */
+
+package org.geysermc.floodgate.crypto;
+
+import org.geysermc.floodgate.util.InvalidHeaderException;
+
+import javax.crypto.Cipher;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.GCMParameterSpec;
+import java.nio.ByteBuffer;
+import java.security.Key;
+import java.security.SecureRandom;
+
+public final class AesCipher implements FloodgateCipher {
+    private static final int IV_LENGTH = 12;
+    private static final int TAG_BIT_LENGTH = 128;
+    private static final String CIPHER_NAME = "AES/GCM/NoPadding";
+
+    private final SecureRandom secureRandom = new SecureRandom();
+    private SecretKey secretKey;
+
+    public void init(Key key) {
+        if (!"AES".equals(key.getAlgorithm())) {
+            throw new RuntimeException(
+                    "Algorithm was expected to be AES, but got " + key.getAlgorithm()
+            );
+        }
+        secretKey = (SecretKey) key;
+    }
+
+    public byte[] encrypt(byte[] data) throws Exception {
+        Cipher cipher = Cipher.getInstance(CIPHER_NAME);
+
+        byte[] iv = new byte[IV_LENGTH];
+        secureRandom.nextBytes(iv);
+
+        GCMParameterSpec spec = new GCMParameterSpec(TAG_BIT_LENGTH, iv);
+        cipher.init(Cipher.ENCRYPT_MODE, secretKey, spec);
+        byte[] cipherText = cipher.doFinal(data);
+
+        return ByteBuffer.allocate(iv.length + cipherText.length + HEADER_LENGTH)
+                .put(IDENTIFIER).put(VERSION) // header
+                .put(iv)
+                .put(cipherText)
+                .array();
+    }
+
+    public byte[] decrypt(byte[] cipherTextWithIv) throws Exception {
+        HeaderResult pair = checkHeader(cipherTextWithIv);
+        if (pair.getVersion() != VERSION) {
+            throw new InvalidHeaderException(
+                    "Expected version " + VERSION + ", got " + pair.getVersion()
+            );
+        }
+
+        Cipher cipher = Cipher.getInstance(CIPHER_NAME);
+
+        int bufferLength = cipherTextWithIv.length - HEADER_LENGTH;
+        ByteBuffer buffer = ByteBuffer.wrap(cipherTextWithIv, HEADER_LENGTH, bufferLength);
+
+        byte[] iv = new byte[IV_LENGTH];
+        buffer.get(iv);
+
+        byte[] cipherText = new byte[buffer.remaining()];
+        buffer.get(cipherText);
+
+        GCMParameterSpec spec = new GCMParameterSpec(TAG_BIT_LENGTH, iv);
+        cipher.init(Cipher.DECRYPT_MODE, secretKey, spec);
+        return cipher.doFinal(cipherText);
+    }
+}

common/src/main/java/org/geysermc/floodgate/crypto/AesKeyProducer.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2019-2020 GeyserMC. http://geysermc.org
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in
+ *  all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ *  THE SOFTWARE.
+ *
+ *  @author GeyserMC
+ *  @link https://github.com/GeyserMC/Floodgate
+ *
+ */
+
+package org.geysermc.floodgate.crypto;
+
+import javax.crypto.KeyGenerator;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.SecretKeySpec;
+import java.security.SecureRandom;
+
+public final class AesKeyProducer implements KeyProducer {
+    public static int KEY_SIZE = 128;
+
+    @Override
+    public SecretKey produce() {
+        try {
+            KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
+            keyGenerator.init(KEY_SIZE, SecureRandom.getInstanceStrong());
+            return keyGenerator.generateKey();
+        } catch (Exception exception) {
+            throw new RuntimeException(exception);
+        }
+    }
+
+    @Override
+    public SecretKey produceFrom(byte[] keyFileData) {
+        try {
+            return new SecretKeySpec(keyFileData, "AES");
+        } catch (Exception exception) {
+            throw new RuntimeException(exception);
+        }
+    }
+}

common/src/main/java/org/geysermc/floodgate/crypto/FloodgateCipher.java

@@ -0,0 +1,165 @@
+/*
+ * Copyright (c) 2019-2020 GeyserMC. http://geysermc.org
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in
+ *  all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ *  THE SOFTWARE.
+ *
+ *  @author GeyserMC
+ *  @link https://github.com/GeyserMC/Floodgate
+ *
+ */
+
+package org.geysermc.floodgate.crypto;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import org.geysermc.floodgate.util.InvalidHeaderException;
+
+import java.nio.charset.StandardCharsets;
+import java.security.Key;
+
+/**
+ * Responsible for both encrypting and decrypting data
+ */
+public interface FloodgateCipher {
+    byte[] IDENTIFIER = "Floodgate".getBytes(StandardCharsets.UTF_8);
+    byte VERSION = 2;
+
+    int HEADER_LENGTH = IDENTIFIER.length + 1; // one byte for version
+
+    /**
+     * Initializes the instance by giving it the key it needs to encrypt or decrypt data
+     *
+     * @param key the key used to encrypt and decrypt data
+     */
+    void init(Key key);
+
+    /**
+     * Encrypts the given data using the Key provided in {@link #init(Key)}
+     *
+     * @param data the data to encrypt
+     * @return the encrypted data
+     * @throws Exception when the encryption failed
+     */
+    byte[] encrypt(byte[] data) throws Exception;
+
+    /**
+     * Encrypts data from a String.<br>
+     * This method internally calls {@link #encrypt(byte[])}
+     *
+     * @param data the data to encrypt
+     * @return the encrypted data
+     * @throws Exception when the encryption failed
+     */
+    default byte[] encryptFromString(String data) throws Exception {
+        return encrypt(data.getBytes(StandardCharsets.UTF_8));
+    }
+
+    /**
+     * Decrypts the given data using the Key provided in {@link #init(Key)}
+     *
+     * @param data the data to decrypt
+     * @return the decrypted data
+     * @throws Exception when the decrypting failed
+     */
+    byte[] decrypt(byte[] data) throws Exception;
+
+    /**
+     * Decrypts a byte[] and turn it into a String.<br>
+     * This method internally calls {@link #decrypt(byte[])}
+     * and converts the returned byte[] into a String.
+     *
+     * @param data the data to encrypt
+     * @return the decrypted data in a UTF-8 String
+     * @throws Exception when the decrypting failed
+     */
+    default String decryptToString(byte[] data) throws Exception {
+        byte[] decrypted = decrypt(data);
+        if (decrypted == null) {
+            return null;
+        }
+        return new String(decrypted, StandardCharsets.UTF_8);
+    }
+
+    /**
+     * Decrypts a String.<br>
+     * This method internally calls {@link #decrypt(byte[])}
+     * by converting the UTF-8 String into a byte[]
+     *
+     * @param data the data to decrypt
+     * @return the decrypted data in a byte[]
+     * @throws Exception when the decrypting failed
+     */
+    default byte[] decryptFromString(String data) throws Exception {
+        return decrypt(data.getBytes(StandardCharsets.UTF_8));
+    }
+
+    /**
+     * Checks if the header is valid and return a IntPair containing the header version
+     * and the index to start reading the actual encrypted data from.
+     *
+     * @param data the data to check
+     * @return IntPair. x = version number, y = the index to start reading from.
+     * @throws InvalidHeaderException when the header is invalid
+     */
+    default HeaderResult checkHeader(byte[] data) throws InvalidHeaderException {
+        final int identifierLength = IDENTIFIER.length;
+
+        if (data.length <= HEADER_LENGTH) {
+            throw new InvalidHeaderException("Data length is smaller then header." +
+                    "Needed " + HEADER_LENGTH + ", got " + data.length);
+        }
+
+        for (int i = 0; i < identifierLength; i++) {
+            if (IDENTIFIER[i] != data[i]) {
+                StringBuilder receivedIdentifier = new StringBuilder();
+                for (byte b : IDENTIFIER) {
+                    receivedIdentifier.append(b);
+                }
+
+                throw new InvalidHeaderException(String.format(
+                        "Expected identifier %s, got %s",
+                        new String(IDENTIFIER, StandardCharsets.UTF_8),
+                        receivedIdentifier.toString()
+                ));
+            }
+        }
+
+        return new HeaderResult(data[identifierLength], HEADER_LENGTH);
+    }
+
+    static boolean hasHeader(String data) {
+        if (data.length() < IDENTIFIER.length) {
+            return false;
+        }
+
+        for (int i = 0; i < IDENTIFIER.length; i++) {
+            if (IDENTIFIER[i] != data.charAt(i)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    @Data
+    @AllArgsConstructor
+    class HeaderResult {
+        private int version;
+        private int startIndex;
+    }
+}

common/src/main/java/org/geysermc/floodgate/crypto/KeyProducer.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2019-2020 GeyserMC. http://geysermc.org
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in
+ *  all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ *  THE SOFTWARE.
+ *
+ *  @author GeyserMC
+ *  @link https://github.com/GeyserMC/Floodgate
+ *
+ */
+
+package org.geysermc.floodgate.crypto;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.security.Key;
+
+public interface KeyProducer {
+    Key produce();
+    Key produceFrom(byte[] keyFileData);
+
+    default Key produceFrom(Path keyFileLocation) throws IOException {
+        return produceFrom(Files.readAllBytes(keyFileLocation));
+    }
+}