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