Core/Entities: Fix exploit/crash in inventory-handling (CMSG_OPEN_ITEM) -thanks to leak

(Adds a scrutiny-based check to baghandling: don't allow placing items in bags that are not "usable" as regular bags)

--HG--
branch : trunk

src/server/game/Server/Protocol/Handlers/SpellHandler.cpp

@@ -221,6 +221,15 @@ void WorldSession::HandleOpenItemOpcode(WorldPacket& recvPacket)
         return;
     }
 
+    // Verify that the bag is an actual bag that can be used "normally"
+    if(!(proto->Flags & ITEM_PROTO_FLAG_OPENABLE))
+    {
+        pUser->SendEquipError(EQUIP_ERR_CANT_DO_RIGHT_NOW, pItem, NULL);
+        sLog.outError("Possible hacking attempt: Player %s [guid: %u] tried to open item [guid: %u, entry: %u] which is not openable!", 
+                pUser->GetName(), pUser->GetGUIDLow(), pItem->GetGUIDLow(), proto->ItemId);
+        return;
+    }
+
     // locked item
     uint32 lockId = proto->LockID;
     if (lockId)