From aea3ab11ab879a8ba31dd560e42848d328410854 Mon Sep 17 00:00:00 2001
From: Zach Brown <zach.brown@destroystokyo.com>
Date: Sun, 10 Jul 2016 10:45:05 -0500
Subject: [PATCH] Block sketchy head items and blocks

---
 .../0166-Block-sketchy-heads.patch            | 122 ++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 Spigot-Server-Patches/0166-Block-sketchy-heads.patch

diff --git a/Spigot-Server-Patches/0166-Block-sketchy-heads.patch b/Spigot-Server-Patches/0166-Block-sketchy-heads.patch
new file mode 100644
index 0000000000..22be90a90f
--- /dev/null
+++ b/Spigot-Server-Patches/0166-Block-sketchy-heads.patch
@@ -0,0 +1,122 @@
+From efa5bad0e1fffbffdea0b131524edb1d2054d6b7 Mon Sep 17 00:00:00 2001
+From: Zach Brown <zach.brown@destroystokyo.com>
+Date: Sat, 9 Jul 2016 20:00:28 -0500
+Subject: [PATCH] Block sketchy heads
+
+Checks for, and blocks, sketchy creative mode spawned, heads.
+Currently only checks for new data, could be added to check all data if needed.
+This is an NMS-port of the work done here: https://github.com/MylesIsCool/SkullExploitPatch by MylesIsCool (_MylesC)
+
+diff --git a/src/main/java/com/destroystokyo/paper/ItemFilter.java b/src/main/java/com/destroystokyo/paper/ItemFilter.java
+new file mode 100644
+index 0000000..9266c19
+--- /dev/null
++++ b/src/main/java/com/destroystokyo/paper/ItemFilter.java
+@@ -0,0 +1,84 @@
++package com.destroystokyo.paper;
++
++import net.minecraft.server.*;
++
++import javax.annotation.Nullable;
++
++public class ItemFilter {
++
++    /**
++     * Checks if the ItemStack passed could be a sketchy head item or block
++     * @param itemStackIn the ItemStack to check
++     * @return whether the item is safe or sketchy
++     */
++    public static boolean isHeadSketchy(@Nullable ItemStack itemStackIn) {
++        if (itemStackIn != null && itemStackIn.getTag() != null) {
++            NBTTagCompound itemTag = itemStackIn.getTag();
++            if (Item.getId(itemStackIn.getItem()) == Item.getId(Items.SKULL) && itemStackIn.getData() == 3) {
++                return isHeadItemSketchy(itemTag);
++            } else if (Item.getId(itemStackIn.getItem()) == Block.getId(Blocks.SKULL)) {
++                return isHeadBlockSketchy(itemTag);
++            }
++
++            // If we can't figure out which is which just run it through both
++            return isHeadItemSketchy(itemTag) || isHeadBlockSketchy(itemTag);
++        }
++        return false;
++    }
++
++    /**
++     * Checks the NBTTagCompound for sketchy data, from the perspective of an Item
++     * @param nbtTagCompound NBTTagCompound from an Item
++     * @return whether the data is safe or sketchy
++     */
++    private static boolean isHeadItemSketchy(NBTTagCompound nbtTagCompound) {
++        if (nbtTagCompound.hasKey("SkullOwner")) {
++            NBTTagCompound skullOwner = nbtTagCompound.getCompound("SkullOwner");
++            if (skullOwner.hasKey("Properties")) {
++                return isHeadNBTSketchy(skullOwner.getCompound("Properties"));
++            }
++        }
++        return false;
++    }
++
++    /**
++     * Checks the NBTTagCompound for sketchy data, from the perspective of a Block
++     * @param nbtTagCompound NBTTagCompound from a Block
++     * @return whether the data is safe or sketchy
++     */
++    private static boolean isHeadBlockSketchy(NBTTagCompound nbtTagCompound) {
++        if (nbtTagCompound.hasKey("Owner")) {
++            NBTTagCompound skullOwner = nbtTagCompound.getCompound("Owner");
++            if (skullOwner.hasKey("Properties")) {
++                return isHeadNBTSketchy(skullOwner.getCompound("Properties"));
++            }
++        }
++        return false;
++    }
++
++    /**
++     * Generified checker for use in both Items and Blocks after some semantics
++     * are done above in the calling methods.
++     * @param properties The generified properties compound from a parent-compound
++     * @return whether the data is safe or sketchy
++     */
++    private static boolean isHeadNBTSketchy(NBTTagCompound properties) {
++        if (properties.hasKey("textures")) {
++            NBTTagList textures = properties.getList("textures", 10);
++            for (NBTBase texture : textures.list) {
++                if (texture instanceof NBTTagCompound) {
++                    if (!((NBTTagCompound) texture).hasKey("Signature")) {
++                        // Check
++                        if (((NBTTagCompound) texture).hasKey("Value")) {
++                            if (((NBTTagCompound) texture).getString("Value").trim().length() > 0) {
++                                return false;
++                            }
++                        }
++                        return true;
++                    }
++                }
++            }
++        }
++        return false;
++    }
++}
+diff --git a/src/main/java/net/minecraft/server/PlayerConnection.java b/src/main/java/net/minecraft/server/PlayerConnection.java
+index 85c62cd..0b1e089 100644
+--- a/src/main/java/net/minecraft/server/PlayerConnection.java
++++ b/src/main/java/net/minecraft/server/PlayerConnection.java
+@@ -2028,6 +2028,15 @@ public class PlayerConnection implements PacketListenerPlayIn, ITickable {
+                 }
+             }
+ 
++            // Paper start - Block sketchy heads
++            if (itemstack != null && (Item.getId(itemstack.getItem()) == Item.getId(Items.SKULL) && itemstack.getData() == 3 || Item.getId(itemstack.getItem()) == Block.getId(Blocks.SKULL))) {
++                if (com.destroystokyo.paper.ItemFilter.isHeadSketchy(itemstack)) {
++                    this.disconnect("Bad creative item!");
++                    return;
++                }
++            }
++            // Paper end
++
+             boolean flag1 = packetplayinsetcreativeslot.a() >= 1 && packetplayinsetcreativeslot.a() <= 45;
+             // CraftBukkit - Add invalidItems check
+             boolean flag2 = itemstack == null || itemstack.getItem() != null && (!invalidItems.contains(Item.getId(itemstack.getItem())) || !org.spigotmc.SpigotConfig.filterCreativeItems); // Spigot
+-- 
+2.9.0
+