From a38587bc0fc5796b4cbd0a8dfe6c59ea554d05ee Mon Sep 17 00:00:00 2001
From: Thinkofdeath <thinkofdeath@spigotmc.org>
Date: Wed, 2 Jul 2014 23:35:51 +0100
Subject: [PATCH] Better item validation


diff --git a/src/main/java/net/minecraft/server/DataWatcher.java b/src/main/java/net/minecraft/server/DataWatcher.java
index 966d737..ca3469f 100644
--- a/src/main/java/net/minecraft/server/DataWatcher.java
+++ b/src/main/java/net/minecraft/server/DataWatcher.java
@@ -154,6 +154,17 @@ public class DataWatcher {
                         arraylist = Lists.newArrayList();
                     }
 
+                    // Spigot start - copy ItemStacks to prevent ConcurrentModificationExceptions
+                    if ( watchableobject.b() instanceof ItemStack )
+                    {
+                        watchableobject = new WatchableObject(
+                                watchableobject.c(),
+                                watchableobject.a(),
+                                ( (ItemStack) watchableobject.b() ).cloneItemStack()
+                        );
+                    }
+                    // Spigot end
+
                     arraylist.add(watchableobject);
                 }
             }
@@ -185,6 +196,21 @@ public class DataWatcher {
         this.f.readLock().lock();
 
         arraylist.addAll(this.dataValues.valueCollection()); // Spigot
+        // Spigot start - copy ItemStacks to prevent ConcurrentModificationExceptions
+        for ( int i = 0; i < arraylist.size(); i++ )
+        {
+            WatchableObject watchableobject = (WatchableObject) arraylist.get( i );
+            if ( watchableobject.b() instanceof ItemStack )
+            {
+                watchableobject = new WatchableObject(
+                        watchableobject.c(),
+                        watchableobject.a(),
+                        ( (ItemStack) watchableobject.b() ).cloneItemStack()
+                );
+                arraylist.set( i, watchableobject );
+            }
+        }
+        // Spigot end
 
         this.f.readLock().unlock();
         return arraylist;
diff --git a/src/main/java/net/minecraft/server/PacketDataSerializer.java b/src/main/java/net/minecraft/server/PacketDataSerializer.java
index 8b7dc17..5227007 100644
--- a/src/main/java/net/minecraft/server/PacketDataSerializer.java
+++ b/src/main/java/net/minecraft/server/PacketDataSerializer.java
@@ -172,6 +172,10 @@ public class PacketDataSerializer extends ByteBuf {
             NBTTagCompound nbttagcompound = null;
 
             if (itemstack.getItem().usesDurability() || itemstack.getItem().p()) {
+                // Spigot start - filter
+                itemstack = itemstack.cloneItemStack();
+                CraftItemStack.setItemMeta(itemstack, CraftItemStack.getItemMeta(itemstack));
+                // Spigot end
                 nbttagcompound = itemstack.getTag();
             }
 
diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBook.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBook.java
index e1badcb..9bf092c 100644
--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBook.java
+++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBook.java
@@ -22,6 +22,10 @@ import net.minecraft.server.IChatBaseComponent;
 import net.minecraft.server.NBTTagString;
 import org.bukkit.craftbukkit.util.CraftChatMessage;
 
+// Spigot start
+import static org.spigotmc.ValidateUtils.*;
+// Spigot end
+
 @DelegateDeserialization(SerializableMeta.class)
 class CraftMetaBook extends CraftMetaItem implements BookMeta {
     static final ItemMetaKey BOOK_TITLE = new ItemMetaKey("title");
@@ -57,11 +61,11 @@ class CraftMetaBook extends CraftMetaItem implements BookMeta {
         super(tag);
 
         if (tag.hasKey(BOOK_TITLE.NBT)) {
-            this.title = tag.getString(BOOK_TITLE.NBT);
+            this.title = limit( tag.getString(BOOK_TITLE.NBT), 1024 ); // Spigot
         }
 
         if (tag.hasKey(BOOK_AUTHOR.NBT)) {
-            this.author = tag.getString(BOOK_AUTHOR.NBT);
+            this.author = limit( tag.getString(BOOK_AUTHOR.NBT), 1024 ); // Spigot
         }
 
         boolean resolved = false;
@@ -86,7 +90,7 @@ class CraftMetaBook extends CraftMetaItem implements BookMeta {
                         // Ignore and treat as an old book
                     }
                 }
-                addPage(page);
+                addPage( limit( page, 2048 ) ); // Spigot
             }
         }
     }
diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
index e80fce2..a4b09fa 100644
--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
+++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
@@ -39,6 +39,10 @@ import com.google.common.collect.Sets;
 import java.util.Arrays;
 import java.util.Set;
 
+// Spigot start
+import static org.spigotmc.ValidateUtils.*;
+// Spigot end
+
 /**
  * Children must include the following:
  *
@@ -238,7 +242,7 @@ class CraftMetaItem implements ItemMeta, Repairable {
             NBTTagCompound display = tag.getCompound(DISPLAY.NBT);
 
             if (display.hasKey(NAME.NBT)) {
-                displayName = display.getString(NAME.NBT);
+                displayName = limit( display.getString(NAME.NBT), 1024 ); // Spigot
             }
 
             if (display.hasKey(LORE.NBT)) {
@@ -246,7 +250,7 @@ class CraftMetaItem implements ItemMeta, Repairable {
                 lore = new ArrayList<String>(list.size());
 
                 for (int index = 0; index < list.size(); index++) {
-                    String line = list.getString(index);
+                    String line = limit( list.getString(index), 1024 ); // Spigot
                     lore.add(line);
                 }
             }
diff --git a/src/main/java/org/spigotmc/ValidateUtils.java b/src/main/java/org/spigotmc/ValidateUtils.java
new file mode 100644
index 0000000..58a9534
--- /dev/null
+++ b/src/main/java/org/spigotmc/ValidateUtils.java
@@ -0,0 +1,14 @@
+package org.spigotmc;
+
+public class ValidateUtils
+{
+
+    public static String limit(String str, int limit)
+    {
+        if ( str.length() > limit )
+        {
+            return str.substring( 0, limit );
+        }
+        return str;
+    }
+}
-- 
2.1.0