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/proxy/VelocityProxy.java b/src/main/java/com/destroystokyo/paper/proxy/VelocityProxy.java new file mode 100644 index 0000000000000000000000000000000000000000..3c31ff3330c2e925e205c0c9ff4f0b832682b576 --- /dev/null +++ b/src/main/java/com/destroystokyo/paper/proxy/VelocityProxy.java @@ -0,0 +1,86 @@ +package com.destroystokyo.paper.proxy; + +import io.papermc.paper.configuration.GlobalConfiguration; +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 java.util.UUID; +import javax.crypto.Mac; +import javax.crypto.spec.SecretKeySpec; +import net.minecraft.network.FriendlyByteBuf; +import net.minecraft.network.protocol.login.custom.CustomQueryPayload; +import net.minecraft.resources.ResourceLocation; +import net.minecraft.world.entity.player.ProfilePublicKey; + +/** + * 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. + */ +public class VelocityProxy { + private static final int SUPPORTED_FORWARDING_VERSION = 1; + public static final int MODERN_FORWARDING_WITH_KEY = 2; + public static final int MODERN_FORWARDING_WITH_KEY_V2 = 3; + public static final int MODERN_LAZY_SESSION = 4; + public static final byte MAX_SUPPORTED_FORWARDING_VERSION = MODERN_LAZY_SESSION; + 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(GlobalConfiguration.get().proxies.velocity.secret.getBytes(java.nio.charset.StandardCharsets.UTF_8), "HmacSHA256")); + final byte[] mySignature = mac.doFinal(data); + if (!MessageDigest.isEqual(signature, mySignature)) { + return false; + } + } catch (final InvalidKeyException | NoSuchAlgorithmException e) { + throw new AssertionError(e); + } + + 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)); + } + } + + public static ProfilePublicKey.Data readForwardedKey(FriendlyByteBuf buf) { + return new ProfilePublicKey.Data(buf); + } + + public static UUID readSignerUuidOrElse(FriendlyByteBuf buf, UUID orElse) { + return buf.readBoolean() ? buf.readUUID() : orElse; + } +} diff --git a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java index bbbadf5284907531eef761a738c3adf5305bd08f..c58e24e0138495748564ff8a08782ffd6522fa38 100644 --- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java +++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java @@ -287,13 +287,20 @@ public class DedicatedServer extends MinecraftServer implements ServerInterface this.server.enablePlugins(org.bukkit.plugin.PluginLoadOrder.STARTUP); // CraftBukkit end + // Paper start - Add Velocity IP Forwarding Support + boolean usingProxy = org.spigotmc.SpigotConfig.bungee || io.papermc.paper.configuration.GlobalConfiguration.get().proxies.velocity.enabled; + String proxyFlavor = (io.papermc.paper.configuration.GlobalConfiguration.get().proxies.velocity.enabled) ? "Velocity" : "BungeeCord"; + String proxyLink = (io.papermc.paper.configuration.GlobalConfiguration.get().proxies.velocity.enabled) ? "https://docs.papermc.io/velocity/security" : "http://www.spigotmc.org/wiki/firewall-guide/"; + // Paper end - Add Velocity IP Forwarding Support if (!this.usesAuthentication()) { DedicatedServer.LOGGER.warn("**** SERVER IS RUNNING IN OFFLINE/INSECURE MODE!"); DedicatedServer.LOGGER.warn("The server will make no attempt to authenticate usernames. Beware."); // Spigot start - if (org.spigotmc.SpigotConfig.bungee) { - DedicatedServer.LOGGER.warn("Whilst this makes it possible to use BungeeCord, unless access to your server is properly restricted, it also opens up the ability for hackers to connect with any username they choose."); - DedicatedServer.LOGGER.warn("Please see http://www.spigotmc.org/wiki/firewall-guide/ for further information."); + // Paper start - Add Velocity IP Forwarding Support + if (usingProxy) { + DedicatedServer.LOGGER.warn("Whilst this makes it possible to use " + proxyFlavor + ", unless access to your server is properly restricted, it also opens up the ability for hackers to connect with any username they choose."); + DedicatedServer.LOGGER.warn("Please see " + proxyLink + " for further information."); + // Paper end - Add Velocity IP Forwarding Support } else { DedicatedServer.LOGGER.warn("While this makes the game possible to play without internet access, it also opens up the ability for hackers to connect with any username they choose."); } diff --git a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java index 9bcded0466f3b10fafd709edc44c60f85cb48b7f..cb006ae0e5be2f1d31261bdd36964229ec44416d 100644 --- a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java +++ b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java @@ -84,6 +84,7 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener, private final boolean transferred; private ServerPlayer player; // CraftBukkit public boolean iKnowThisMayNotBeTheBestIdeaButPleaseDisableUsernameValidation = false; // Paper - username validation overriding + private int velocityLoginMessageId = -1; // Paper - Add Velocity IP Forwarding Support public ServerLoginPacketListenerImpl(MinecraftServer server, Connection connection, boolean transferred) { this.state = ServerLoginPacketListenerImpl.State.HELLO; @@ -182,6 +183,16 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener, this.state = ServerLoginPacketListenerImpl.State.KEY; this.connection.send(new ClientboundHelloPacket("", this.server.getKeyPair().getPublic().getEncoded(), this.challenge, true)); } else { + // Paper start - Add Velocity IP Forwarding Support + if (io.papermc.paper.configuration.GlobalConfiguration.get().proxies.velocity.enabled) { + this.velocityLoginMessageId = java.util.concurrent.ThreadLocalRandom.current().nextInt(); + net.minecraft.network.FriendlyByteBuf buf = new net.minecraft.network.FriendlyByteBuf(io.netty.buffer.Unpooled.buffer()); + buf.writeByte(com.destroystokyo.paper.proxy.VelocityProxy.MAX_SUPPORTED_FORWARDING_VERSION); + net.minecraft.network.protocol.login.ClientboundCustomQueryPacket packet1 = new net.minecraft.network.protocol.login.ClientboundCustomQueryPacket(this.velocityLoginMessageId, new net.minecraft.network.protocol.login.ClientboundCustomQueryPacket.PlayerInfoChannelPayload(com.destroystokyo.paper.proxy.VelocityProxy.PLAYER_INFO_CHANNEL, buf)); + this.connection.send(packet1); + return; + } + // Paper end - Add Velocity IP Forwarding Support // CraftBukkit start // Paper start - Cache authenticator threads authenticatorPool.execute(new Runnable() { @@ -334,6 +345,12 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener, // CraftBukkit start private GameProfile callPlayerPreLoginEvents(GameProfile gameprofile) throws Exception { // Paper - Add more fields to AsyncPlayerPreLoginEvent + // Paper start - Add Velocity IP Forwarding Support + if (ServerLoginPacketListenerImpl.this.velocityLoginMessageId == -1 && io.papermc.paper.configuration.GlobalConfiguration.get().proxies.velocity.enabled) { + disconnect("This server requires you to connect with Velocity."); + return gameprofile; + } + // Paper end - Add Velocity IP Forwarding Support String playerName = gameprofile.getName(); java.net.InetAddress address = ((java.net.InetSocketAddress) this.connection.getRemoteAddress()).getAddress(); java.util.UUID uniqueId = gameprofile.getId(); @@ -379,6 +396,51 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener, @Override public void handleCustomQueryPacket(ServerboundCustomQueryAnswerPacket packet) { + // Paper start - Add Velocity IP Forwarding Support + if (io.papermc.paper.configuration.GlobalConfiguration.get().proxies.velocity.enabled && packet.transactionId() == this.velocityLoginMessageId) { + ServerboundCustomQueryAnswerPacket.QueryAnswerPayload payload = (ServerboundCustomQueryAnswerPacket.QueryAnswerPayload)packet.payload(); + if (payload == null) { + this.disconnect("This server requires you to connect with Velocity."); + return; + } + + net.minecraft.network.FriendlyByteBuf buf = payload.buffer; + + if (!com.destroystokyo.paper.proxy.VelocityProxy.checkIntegrity(buf)) { + this.disconnect("Unable to verify player details"); + return; + } + + int version = buf.readVarInt(); + if (version > com.destroystokyo.paper.proxy.VelocityProxy.MAX_SUPPORTED_FORWARDING_VERSION) { + throw new IllegalStateException("Unsupported forwarding version " + version + ", wanted upto " + com.destroystokyo.paper.proxy.VelocityProxy.MAX_SUPPORTED_FORWARDING_VERSION); + } + + 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.authenticatedProfile = com.destroystokyo.paper.proxy.VelocityProxy.createProfile(buf); + + //TODO Update handling for lazy sessions, might not even have to do anything? + + // Proceed with login + authenticatorPool.execute(() -> { + try { + final GameProfile gameprofile = this.callPlayerPreLoginEvents(this.authenticatedProfile); + ServerLoginPacketListenerImpl.LOGGER.info("UUID of player {} is {}", gameprofile.getName(), gameprofile.getId()); + ServerLoginPacketListenerImpl.this.startClientVerification(gameprofile); + } catch (Exception ex) { + disconnect("Failed to verify username!"); + server.server.getLogger().log(java.util.logging.Level.WARNING, "Exception verifying " + this.authenticatedProfile.getName(), ex); + } + }); + return; + } + // Paper end - Add Velocity IP Forwarding Support this.disconnect(ServerCommonPacketListenerImpl.DISCONNECT_UNEXPECTED_QUERY); } diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java index 8b629647c15721207f14081832bea6a702359b77..e135d634f4336a23e90fd94b4e4c261bfc0cffe9 100644 --- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java +++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java @@ -833,7 +833,7 @@ 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 || io.papermc.paper.configuration.GlobalConfiguration.get().proxies.velocity.enabled) { // Paper - Add Velocity IP Forwarding Support return -1; } else { return this.configuration.getInt("settings.connection-throttle");