From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Andrew Steinborn Date: Mon, 8 Oct 2018 14:36:14 -0400 Subject: [PATCH] Add Velocity IP Forwarding Support While Velocity supports BungeeCord-style IP forwarding, it is not secure. Users have a lot of problems setting up firewalls or setting up plugins like IPWhitelist. Further, the BungeeCord IP forwarding protocol still retains essentially its original form, when there is brand new support for custom login plugin messages in 1.13. Velocity's modern IP forwarding uses an HMAC-SHA256 code to ensure authenticity of messages, is packed into a binary format that is smaller than BungeeCord's forwarding, and is integrated into the Minecraft login process by using the 1.13 login plugin message packet. diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java index 585be2fcbd63a59f911df69136eae07ce665053c..9768c591e72ce2ef5fdb43e2fc63378c57773216 100644 --- a/src/main/java/com/destroystokyo/paper/PaperConfig.java +++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java @@ -9,6 +9,7 @@ import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.Modifier; +import java.nio.charset.StandardCharsets; import java.util.HashMap; import java.util.List; import java.util.Map; @@ -253,7 +254,7 @@ public class PaperConfig { } public static boolean isProxyOnlineMode() { - return Bukkit.getOnlineMode() || (SpigotConfig.bungee && bungeeOnlineMode); + return Bukkit.getOnlineMode() || (SpigotConfig.bungee && bungeeOnlineMode) || (velocitySupport && velocityOnlineMode); } public static int packetInSpamThreshold = 300; @@ -326,6 +327,20 @@ public class PaperConfig { tabSpamLimit = getInt("settings.spam-limiter.tab-spam-limit", tabSpamLimit); } + public static boolean velocitySupport; + public static boolean velocityOnlineMode; + public static byte[] velocitySecretKey; + private static void velocitySupport() { + velocitySupport = getBoolean("settings.velocity-support.enabled", false); + velocityOnlineMode = getBoolean("settings.velocity-support.online-mode", false); + String secret = getString("settings.velocity-support.secret", ""); + if (velocitySupport && secret.isEmpty()) { + fatal("Velocity support is enabled, but no secret key was specified. A secret key is required!"); + } else { + velocitySecretKey = secret.getBytes(StandardCharsets.UTF_8); + } + } + public static boolean asyncChunks = false; private static void asyncChunks() { ConfigurationSection section; diff --git a/src/main/java/com/destroystokyo/paper/proxy/VelocityProxy.java b/src/main/java/com/destroystokyo/paper/proxy/VelocityProxy.java new file mode 100644 index 0000000000000000000000000000000000000000..41d73aa91fb401612e087aa1b7278ba61d28bf3a --- /dev/null +++ b/src/main/java/com/destroystokyo/paper/proxy/VelocityProxy.java @@ -0,0 +1,66 @@ +package com.destroystokyo.paper.proxy; + +import com.destroystokyo.paper.PaperConfig; +import com.google.common.net.InetAddresses; +import com.mojang.authlib.GameProfile; +import com.mojang.authlib.properties.Property; +import java.net.InetAddress; +import java.security.InvalidKeyException; +import java.security.MessageDigest; +import java.security.NoSuchAlgorithmException; + +import javax.crypto.Mac; +import javax.crypto.spec.SecretKeySpec; +import net.minecraft.network.FriendlyByteBuf; +import net.minecraft.resources.ResourceLocation; + +public class VelocityProxy { + private static final int SUPPORTED_FORWARDING_VERSION = 1; + public static final ResourceLocation PLAYER_INFO_CHANNEL = new ResourceLocation("velocity", "player_info"); + + public static boolean checkIntegrity(final FriendlyByteBuf buf) { + final byte[] signature = new byte[32]; + buf.readBytes(signature); + + final byte[] data = new byte[buf.readableBytes()]; + buf.getBytes(buf.readerIndex(), data); + + try { + final Mac mac = Mac.getInstance("HmacSHA256"); + mac.init(new SecretKeySpec(PaperConfig.velocitySecretKey, "HmacSHA256")); + final byte[] mySignature = mac.doFinal(data); + if (!MessageDigest.isEqual(signature, mySignature)) { + return false; + } + } catch (final InvalidKeyException | NoSuchAlgorithmException e) { + throw new AssertionError(e); + } + + int version = buf.readVarInt(); + if (version != SUPPORTED_FORWARDING_VERSION) { + throw new IllegalStateException("Unsupported forwarding version " + version + ", wanted " + SUPPORTED_FORWARDING_VERSION); + } + + return true; + } + + public static InetAddress readAddress(final FriendlyByteBuf buf) { + return InetAddresses.forString(buf.readUtf(Short.MAX_VALUE)); + } + + public static GameProfile createProfile(final FriendlyByteBuf buf) { + final GameProfile profile = new GameProfile(buf.readUUID(), buf.readUtf(16)); + readProperties(buf, profile); + return profile; + } + + private static void readProperties(final FriendlyByteBuf buf, final GameProfile profile) { + final int properties = buf.readVarInt(); + for (int i1 = 0; i1 < properties; i1++) { + final String name = buf.readUtf(Short.MAX_VALUE); + final String value = buf.readUtf(Short.MAX_VALUE); + final String signature = buf.readBoolean() ? buf.readUtf(Short.MAX_VALUE) : null; + profile.getProperties().put(name, new Property(name, value, signature)); + } + } +} diff --git a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java index 1d05725374bdffad6a8ab1502ee732775345024d..a196ab2510a1c302ef1c946400c1a7c07619994a 100644 --- a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java +++ b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java @@ -18,6 +18,7 @@ import javax.crypto.Cipher; import javax.crypto.SecretKey; import net.minecraft.DefaultUncaughtExceptionHandler; import net.minecraft.network.Connection; +import net.minecraft.network.FriendlyByteBuf; import net.minecraft.network.chat.Component; import net.minecraft.network.chat.TextComponent; import net.minecraft.network.chat.TranslatableComponent; @@ -44,6 +45,7 @@ import org.bukkit.craftbukkit.util.Waitable; import org.bukkit.event.player.AsyncPlayerPreLoginEvent; import org.bukkit.event.player.PlayerPreLoginEvent; // CraftBukkit end +import io.netty.buffer.Unpooled; // Paper public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener { @@ -62,6 +64,7 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener @Nullable private ServerPlayer delayedAcceptPlayer; public String hostname = ""; // CraftBukkit - add field + private int velocityLoginMessageId = -1; // Paper - Velocity support public ServerLoginPacketListenerImpl(MinecraftServer server, Connection connection) { this.state = ServerLoginPacketListenerImpl.State.HELLO; @@ -233,6 +236,14 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener this.state = ServerLoginPacketListenerImpl.State.KEY; this.connection.send(new ClientboundHelloPacket("", this.server.getKeyPair().getPublic().getEncoded(), this.nonce)); } else { + // Paper start - Velocity support + if (com.destroystokyo.paper.PaperConfig.velocitySupport) { + this.velocityLoginMessageId = java.util.concurrent.ThreadLocalRandom.current().nextInt(); + net.minecraft.network.protocol.login.ClientboundCustomQueryPacket packet1 = new net.minecraft.network.protocol.login.ClientboundCustomQueryPacket(this.velocityLoginMessageId, com.destroystokyo.paper.proxy.VelocityProxy.PLAYER_INFO_CHANNEL, new FriendlyByteBuf(Unpooled.EMPTY_BUFFER)); + this.connection.send(packet1); + return; + } + // Paper end // Spigot start // Paper start - Cache authenticator threads authenticatorPool.execute(new Runnable() { @@ -334,6 +345,12 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener public class LoginHandler { public void fireEvents() throws Exception { + // Paper start - Velocity support + if (ServerLoginPacketListenerImpl.this.velocityLoginMessageId == -1 && com.destroystokyo.paper.PaperConfig.velocitySupport) { + disconnect("This server requires you to connect with Velocity."); + return; + } + // Paper end String playerName = ServerLoginPacketListenerImpl.this.gameProfile.getName(); java.net.InetAddress address = ((java.net.InetSocketAddress) ServerLoginPacketListenerImpl.this.connection.getRemoteAddress()).getAddress(); java.util.UUID uniqueId = ServerLoginPacketListenerImpl.this.gameProfile.getId(); @@ -381,6 +398,40 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener // Spigot end public void handleCustomQueryPacket(ServerboundCustomQueryPacket packet) { + // Paper start - Velocity support + if (com.destroystokyo.paper.PaperConfig.velocitySupport && packet.getTransactionId() == this.velocityLoginMessageId) { + FriendlyByteBuf buf = packet.getData(); + if (buf == null) { + this.disconnect("This server requires you to connect with Velocity."); + return; + } + + if (!com.destroystokyo.paper.proxy.VelocityProxy.checkIntegrity(buf)) { + this.disconnect("Unable to verify player details"); + return; + } + + java.net.SocketAddress listening = this.connection.getRemoteAddress(); + int port = 0; + if (listening instanceof java.net.InetSocketAddress) { + port = ((java.net.InetSocketAddress) listening).getPort(); + } + this.connection.address = new java.net.InetSocketAddress(com.destroystokyo.paper.proxy.VelocityProxy.readAddress(buf), port); + + this.gameProfile = com.destroystokyo.paper.proxy.VelocityProxy.createProfile(buf); + + // Proceed with login + authenticatorPool.execute(() -> { + try { + new LoginHandler().fireEvents(); + } catch (Exception ex) { + disconnect("Failed to verify username!"); + server.server.getLogger().log(java.util.logging.Level.WARNING, "Exception verifying " + gameProfile.getName(), ex); + } + }); + return; + } + // Paper end this.disconnect(new TranslatableComponent("multiplayer.disconnect.unexpected_query_response")); } diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java index 16645b4c096936c4d5c00f335e5cdb7dd4a4e2bd..717ad1c24bbc882db8f76cfef7bf847c58914e5a 100644 --- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java +++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java @@ -683,7 +683,7 @@ public final class CraftServer implements Server { @Override public long getConnectionThrottle() { // Spigot Start - Automatically set connection throttle for bungee configurations - if (org.spigotmc.SpigotConfig.bungee) { + if (org.spigotmc.SpigotConfig.bungee || com.destroystokyo.paper.PaperConfig.velocitySupport) { // Paper - Velocity support return -1; } else { return this.configuration.getInt("settings.connection-throttle");