From a294666b73306af83ef4b4416721a0d67754272b Mon Sep 17 00:00:00 2001
From: Tux <write@imaginarycode.com>
Date: Tue, 25 Oct 2016 12:34:41 -0400
Subject: [PATCH] Validate that chat messages are non-blank


diff --git a/proxy/src/main/java/io/github/waterfallmc/waterfall/StringUtil.java b/proxy/src/main/java/io/github/waterfallmc/waterfall/StringUtil.java
new file mode 100644
index 00000000..940ad806
--- /dev/null
+++ b/proxy/src/main/java/io/github/waterfallmc/waterfall/StringUtil.java
@@ -0,0 +1,22 @@
+package io.github.waterfallmc.waterfall;
+
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class StringUtil {
+    public static boolean isBlank(String str) {
+        if (str.isEmpty()) {
+            return true;
+        }
+
+        int l = str.length();
+        for (int i = 0; i < l; i++) {
+            if (!Character.isWhitespace(str.charAt(i))) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}
diff --git a/proxy/src/main/java/net/md_5/bungee/connection/UpstreamBridge.java b/proxy/src/main/java/net/md_5/bungee/connection/UpstreamBridge.java
index 2526ef16..6b79875d 100644
--- a/proxy/src/main/java/net/md_5/bungee/connection/UpstreamBridge.java
+++ b/proxy/src/main/java/net/md_5/bungee/connection/UpstreamBridge.java
@@ -1,6 +1,7 @@
 package net.md_5.bungee.connection;
 
 import com.google.common.base.Preconditions;
+import io.github.waterfallmc.waterfall.StringUtil;
 import io.netty.channel.Channel;
 import java.util.ArrayList;
 import java.util.List;
@@ -131,6 +132,7 @@ public class UpstreamBridge extends PacketHandler
     {
         int maxLength = ( con.getPendingConnection().getVersion() >= ProtocolConstants.MINECRAFT_1_11 ) ? 256 : 100;
         Preconditions.checkArgument( chat.getMessage().length() <= maxLength, "Chat message too long" ); // Mojang limit, check on updates
+        Preconditions.checkArgument(!StringUtil.isBlank(chat.getMessage()), "Chat message is empty");
 
         ChatEvent chatEvent = new ChatEvent( con, con.getServer(), chat.getMessage() );
         if ( !bungee.getPluginManager().callEvent( chatEvent ).isCancelled() )
-- 
2.14.1