mirrors/PocketMine-MP
1
0
Fork 0
mirror of https://github.com/pmmp/PocketMine-MP.git synced 2025-07-20 18:06:40 +00:00
Code Issues Projects Releases Wiki Activity

Fixed mismatched predictions due to NBT key order differences

Browse Source 
this is a pain :(
It appears the client always sorts the keys in alphabetical order due to use of std::map. However I'm not sure of the exact ordering behaviour, so it needs to be investigated.
This commit is contained in:
Dylan K. Taylor 2024-02-27 16:07:43 +00:00
parent 6872118355
commit a0cca53f52
No known key found for this signature in database
GPG Key ID: 8927471A91CAFD3D
3 changed files with 56 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
src/network/mcpe/InventoryManager.php
View File

@ -423,6 +423,41 @@ class InventoryManager{
}
}
/**
* Compares itemstack extra data for equality. This is used to verify legacy InventoryTransaction slot predictions.
*
* TODO: It would be preferable if we didn't have to deserialize this, to improve performance and reduce attack
* surface. However, the raw data may not match due to differences in ordering. Investigate whether the
* client-provided NBT is consistently sorted.
*/
private function itemStackExtraDataEqual(ItemStack $left, ItemStack $right) : bool{
if($left->getRawExtraData() === $right->getRawExtraData()){
return true;
}
$typeConverter = $this->session->getTypeConverter();
$leftExtraData = $typeConverter->deserializeItemStackExtraData($left->getRawExtraData(), $left->getId());
$rightExtraData = $typeConverter->deserializeItemStackExtraData($right->getRawExtraData(), $right->getId());
$leftNbt = $leftExtraData->getNbt();
$rightNbt = $rightExtraData->getNbt();
return
$leftExtraData->getCanPlaceOn() === $rightExtraData->getCanPlaceOn() &&
$leftExtraData->getCanDestroy() === $rightExtraData->getCanDestroy() && (
$leftNbt === $rightNbt || //this covers null === null and fast object identity
($leftNbt !== null && $rightNbt !== null && $leftNbt->equals($rightNbt))
);
}
private function itemStacksEqual(ItemStack $left, ItemStack $right) : bool{
return
$left->getId() === $right->getId() &&
$left->getMeta() === $right->getMeta() &&
$left->getBlockRuntimeId() === $right->getBlockRuntimeId() &&
$left->getCount() === $right->getCount() &&
$this->itemStackExtraDataEqual($left, $right);
}
public function onSlotChange(Inventory $inventory, int $slot) : void{
$inventoryEntry = $this->inventories[spl_object_id($inventory)] ?? null;
if($inventoryEntry === null){
@ -432,7 +467,7 @@ class InventoryManager{
}
$currentItem = $this->session->getTypeConverter()->coreItemStackToNet($inventory->getItem($slot));
$clientSideItem = $inventoryEntry->predictions[$slot] ?? null;
if($clientSideItem === null || !$clientSideItem->equals($currentItem)){
if($clientSideItem === null || !$this->itemStacksEqual($currentItem, $clientSideItem)){
//no prediction or incorrect - do not associate this with the currently active itemstack request
$this->trackItemStack($inventoryEntry, $slot, $currentItem, null);
$inventoryEntry->pendingSyncs[$slot] = $currentItem;

12
src/network/mcpe/convert/TypeConverter.php
View File

@ -248,10 +248,7 @@ class TypeConverter{
if($itemStack->getId() === 0){
return VanillaItems::AIR();
}
$extraDataDeserializer = PacketSerializer::decoder($itemStack->getRawExtraData(), 0);
$extraData = $itemStack->getId() === $this->shieldRuntimeId ?
ItemStackExtraDataShield::read($extraDataDeserializer) :
ItemStackExtraData::read($extraDataDeserializer);
$extraData = $this->deserializeItemStackExtraData($itemStack->getRawExtraData(), $itemStack->getId());
$compound = $extraData->getNbt();
@ -272,4 +269,11 @@ class TypeConverter{
return $itemResult;
}
public function deserializeItemStackExtraData(string $extraData, int $id) : ItemStackExtraData{
$extraDataDeserializer = PacketSerializer::decoder($extraData, 0);
return $id === $this->shieldRuntimeId ?
ItemStackExtraDataShield::read($extraDataDeserializer) :
ItemStackExtraData::read($extraDataDeserializer);
}
}

15
src/network/mcpe/handler/InGamePacketHandler.php
View File

@ -444,9 +444,18 @@ class InGamePacketHandler extends PacketHandler{
return false;
}
$serverItemStack = $this->session->getTypeConverter()->coreItemStackToNet($sourceSlotItem);
//because the client doesn't tell us the expected itemstack ID, we have to deep-compare our known
//itemstack info with the one the client sent. This is costly, but we don't have any other option :(
if(!$serverItemStack->equals($clientItemStack)){
//Sadly we don't have itemstack IDs here, so we have to compare the basic item properties to ensure that we're
//dropping the item the client expects (inventory might be out of sync with the client).
if(
$serverItemStack->getId() !== $clientItemStack->getId() ||
$serverItemStack->getMeta() !== $clientItemStack->getMeta() ||
$serverItemStack->getCount() !== $clientItemStack->getCount() ||
$serverItemStack->getBlockRuntimeId() !== $clientItemStack->getBlockRuntimeId()
//Raw extraData may not match because of TAG_Compound key ordering differences, and decoding it to compare
//is costly. Assume that we're in sync if id+meta+count+runtimeId match.
//NB: Make sure $clientItemStack isn't used to create the dropped item, as that would allow the client
//to change the item NBT since we're not validating it.
){
return false;
}