From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <nassim@njahnke.dev>
Date: Mon, 11 Sep 2023 12:01:57 +1000
Subject: [PATCH] Add slot sanity checks in container clicks


diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index 236ab643cdd65b3572860aedf1f5ac18ff96139a..65bb221993147a558995b36fb835f7b82e0eb4bd 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -2981,6 +2981,12 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
                             break;
                         case SWAP:
                             if ((packet.getButtonNum() >= 0 && packet.getButtonNum() < 9) || packet.getButtonNum() == 40) {
+                                // Paper start
+                                if (packet.getSlotNum() < 0) {
+                                    action = InventoryAction.NOTHING;
+                                    break;
+                                }
+                                // Paper end
                                 click = (packet.getButtonNum() == 40) ? ClickType.SWAP_OFFHAND : ClickType.NUMBER_KEY;
                                 Slot clickedSlot = this.player.containerMenu.getSlot(packet.getSlotNum());
                                 if (clickedSlot.mayPickup(this.player)) {
diff --git a/src/main/java/net/minecraft/world/inventory/AbstractContainerMenu.java b/src/main/java/net/minecraft/world/inventory/AbstractContainerMenu.java
index 3ef712299fe248602b0b117c0a8e285cdf4e05c2..5d298b11f74cd2da47e6613ced621ab62aa73a7b 100644
--- a/src/main/java/net/minecraft/world/inventory/AbstractContainerMenu.java
+++ b/src/main/java/net/minecraft/world/inventory/AbstractContainerMenu.java
@@ -423,6 +423,7 @@ public abstract class AbstractContainerMenu {
                     this.resetQuickCraft();
                 }
             } else if (this.quickcraftStatus == 1) {
+                if (slotIndex < 0) return; // Paper
                 slot = (Slot) this.slots.get(slotIndex);
                 itemstack = this.getCarried();
                 if (AbstractContainerMenu.canItemQuickReplace(slot, itemstack, true) && slot.mayPlace(itemstack) && (this.quickcraftType == 2 || itemstack.getCount() > this.quickcraftSlots.size()) && this.canDragTo(slot)) {
@@ -598,6 +599,7 @@ public abstract class AbstractContainerMenu {
                 int j2;
 
                 if (actionType == ClickType.SWAP) {
+                    if (slotIndex < 0 || button < 0) return; // Paper
                     slot2 = (Slot) this.slots.get(slotIndex);
                     itemstack1 = playerinventory.getItem(button);
                     itemstack = slot2.getItem();