papermc/CraftBukkit-Patches/0039-Prevent-handshake-spam-from-invalid-names.patch

From d8a60325ae53f811ad456e3b0738de3ccd02360e Mon Sep 17 00:00:00 2001
From: Benjamin James Harrison-Sims <tehrainbowguy@gmail.com>
Date: Sun, 14 Apr 2013 03:08:51 +0100
Subject: [PATCH] Prevent handshake spam from invalid names.


diff --git a/src/main/java/net/minecraft/server/Packet2Handshake.java b/src/main/java/net/minecraft/server/Packet2Handshake.java
index 343af93..aa6609b 100644
--- a/src/main/java/net/minecraft/server/Packet2Handshake.java
+++ b/src/main/java/net/minecraft/server/Packet2Handshake.java
@@ -1,5 +1,7 @@
 package net.minecraft.server;
 
+import org.bukkit.craftbukkit.Spigot;
+
 import java.io.DataInputStream;
 import java.io.DataOutputStream;
 
@@ -19,6 +21,7 @@ public class Packet2Handshake extends Packet {
         this.b = a(datainputstream, 16);
         this.c = a(datainputstream, 255);
         this.d = datainputstream.readInt();
+        if(!Spigot.validName.matcher(this.b).matches()) throw new IOException("Invalid name!"); // Spigot
     }
 
     public void a(DataOutputStream dataoutputstream) throws IOException { // CraftBukkit - throws IOException
diff --git a/src/main/java/org/bukkit/craftbukkit/Spigot.java b/src/main/java/org/bukkit/craftbukkit/Spigot.java
index 504bd8b..5bf5c10 100644
--- a/src/main/java/org/bukkit/craftbukkit/Spigot.java
+++ b/src/main/java/org/bukkit/craftbukkit/Spigot.java
@@ -9,6 +9,8 @@ import org.bukkit.configuration.file.YamlConfiguration;
 
 import java.util.List;
 import java.util.logging.Level;
+import java.util.regex.Pattern;
+
 import net.minecraft.server.EntityPlayer;
 import org.bukkit.Bukkit;
 import org.spigotmc.Metrics;
@@ -25,6 +27,7 @@ public class Spigot {
     private static Metrics metrics;
     public static List<String> bungeeIPs;
     public static int textureResolution = 16;
+    public static final Pattern validName = Pattern.compile("^[a-zA-Z0-9_]{3,16}$");
 
     public static void initialize(CraftServer server, SimpleCommandMap commandMap, YamlConfiguration configuration) {
         commandMap.register("bukkit", new org.bukkit.craftbukkit.command.TicksPerSecondCommand("tps"));
-- 
1.8.2.1