Check for USE_ITEM after stupidity

SamB440 · Jan 16, 2024 · ac55e2e · ac55e2e
1 parent 9660021
commit ac55e2e
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Showing 20 changed files with 277 additions and 23 deletions.
diff --git a/src/main/java/ac/grim/grimac/checks/impl/badpackets/BadPacketsU.java b/src/main/java/ac/grim/grimac/checks/impl/badpackets/BadPacketsU.java
@@ -0,0 +1,20 @@
+package ac.grim.grimac.checks.impl.badpackets;
+
+import ac.grim.grimac.checks.Check;
+import ac.grim.grimac.checks.CheckData;
+import ac.grim.grimac.checks.type.PacketCheck;
+import ac.grim.grimac.player.GrimPlayer;
+import ac.grim.grimac.utils.data.packetentity.PacketEntity;
+import com.github.retrooper.packetevents.event.PacketReceiveEvent;
+import com.github.retrooper.packetevents.protocol.entity.type.EntityTypes;
+import com.github.retrooper.packetevents.protocol.packettype.PacketType;
+import com.github.retrooper.packetevents.wrapper.play.client.WrapperPlayClientInteractEntity;
+
+@CheckData(name = "BadPacketsU")
+public class BadPacketsU extends Check implements PacketCheck {
+
+    public BadPacketsU(final GrimPlayer player) {
+        super(player);
+    }
+
+}
diff --git a/src/main/java/ac/grim/grimac/events/packets/CheckManagerListener.java b/src/main/java/ac/grim/grimac/events/packets/CheckManagerListener.java
@@ -42,7 +42,6 @@
 import com.github.retrooper.packetevents.wrapper.PacketWrapper;
 import com.github.retrooper.packetevents.wrapper.play.client.*;
 import com.github.retrooper.packetevents.wrapper.play.server.WrapperPlayServerAcknowledgeBlockChanges;
-import com.github.retrooper.packetevents.wrapper.play.server.WrapperPlayServerBlockChange;
 import com.github.retrooper.packetevents.wrapper.play.server.WrapperPlayServerSetSlot;
 import io.github.retrooper.packetevents.util.SpigotConversionUtil;
 import org.bukkit.util.Vector;
@@ -54,7 +53,7 @@
 public class CheckManagerListener extends PacketListenerAbstract {
 
     public CheckManagerListener() {
-        super(PacketListenerPriority.LOW);
+        super(PacketListenerPriority.NORMAL);
     }
 
     // Copied from MCP...
@@ -314,33 +313,61 @@ private static void handleBlockPlaceOrUseItem(PacketWrapper packet, GrimPlayer p
     }
 
     private boolean isMojangStupid(GrimPlayer player, WrapperPlayClientPlayerFlying flying) {
+        if (player.packetStateData.lastPacketWasTeleport) {
+            // Just assume the player could have sent a stupidity packet in a teleport, for enforcement check
+            player.packetStateData.lastTeleportWasPotentiallyOnePointSeventeenDuplicate = true;
+            player.packetStateData.lastStupidity = null;
+            return false;
+        }
+
+        final Location location = flying.getLocation();
         double threshold = player.getMovementThreshold();
         // Don't check duplicate 1.17 packets (Why would you do this mojang?)
         // Don't check rotation since it changes between these packets, with the second being irrelevant.
         //
         // removed a large rant, but I'm keeping this out of context insult below
         // EVEN A BUNCH OF MONKEYS ON A TYPEWRITER COULDNT WRITE WORSE NETCODE THAN MOJANG
-        if (!player.packetStateData.lastPacketWasTeleport && flying.hasPositionChanged() && flying.hasRotationChanged() &&
+        final double distance = player.filterMojangStupidityOnMojangStupidity.distanceSquared(location.getPosition());
+        if (flying.hasPositionChanged() && flying.hasRotationChanged() &&
                 // Ground status will never change in this stupidity packet
                 ((flying.isOnGround() == player.packetStateData.packetPlayerOnGround
                         // Mojang added this stupid mechanic in 1.17
                         && (player.getClientVersion().isNewerThanOrEquals(ClientVersion.V_1_17) &&
                         // Due to 0.03, we can't check exact position, only within 0.03
-                        player.filterMojangStupidityOnMojangStupidity.distanceSquared(flying.getLocation().getPosition()) < threshold * threshold))
+                        distance < threshold * threshold))
                         // If the player was in a vehicle, has position and look, and wasn't a teleport, then it was this stupid packet
                         || player.compensatedEntities.getSelf().inVehicle())) {
+            // Player can only send this stupidity packet when holding an item
+            if (player.getInventory().getOffHand().isEmpty() && player.getInventory().getHeldItem().isEmpty()) {
+                return false;
+            }
+
+            // We detected this as a stupidity packet but due to lack of USE_ITEM after we were wrong
+            if (player.packetStateData.ignoreDuplicatePacket) {
+                player.packetStateData.ignoreDuplicatePacket = false;
+                return false;
+            }
+
+            player.packetStateData.detectedStupidity = true;
+            player.packetStateData.lastStupidity = location;
+
+            // Mark that we want this packet to be cancelled from reaching the server
+            // Since we delay USE_ITEM until the next valid flying packet, this is not an issue.
+            // Additionally, only yaw/pitch matters: https://github.com/GrimAnticheat/Grim/issues/1275#issuecomment-1872444018
+            player.packetStateData.cancelDuplicatePacket = true;
+
             player.packetStateData.lastPacketWasOnePointSeventeenDuplicate = true;
 
-            if (player.xRot != flying.getLocation().getYaw() || player.yRot != flying.getLocation().getPitch()) {
+            if (player.xRot != location.getYaw() || player.yRot != location.getPitch()) {
                 player.lastXRot = player.xRot;
                 player.lastYRot = player.yRot;
             }
 
             // Take the pitch and yaw, just in case we were wrong about this being a stupidity packet
-            player.xRot = flying.getLocation().getYaw();
-            player.yRot = flying.getLocation().getPitch();
+            player.xRot = location.getYaw();
+            player.yRot = location.getPitch();
 
-            player.packetStateData.lastClaimedPosition = flying.getLocation().getPosition();
+            player.packetStateData.lastClaimedPosition = location.getPosition();
             return true;
         }
         return false;
@@ -369,7 +396,7 @@ public void onPacketReceive(PacketReceiveEvent event) {
             teleportData = flying.hasPositionChanged() && flying.hasRotationChanged() ? player.getSetbackTeleportUtil().checkTeleportQueue(position.getX(), position.getY(), position.getZ()) : new TeleportAcceptData();
             player.packetStateData.lastPacketWasTeleport = teleportData.isTeleport();
             // Teleports can't be stupidity packets
-            player.packetStateData.lastPacketWasOnePointSeventeenDuplicate = !player.packetStateData.lastPacketWasTeleport && isMojangStupid(player, flying);
+            player.packetStateData.lastPacketWasOnePointSeventeenDuplicate = isMojangStupid(player, flying);
         }
 
 
@@ -392,6 +419,7 @@ public void onPacketReceive(PacketReceiveEvent event) {
 
         // The player flagged crasher or timer checks, therefore we must protect predictions against these attacks
         if (event.isCancelled() && (WrapperPlayClientPlayerFlying.isFlying(event.getPacketType()) || event.getPacketType() == PacketType.Play.Client.VEHICLE_MOVE)) {
+            player.packetStateData.cancelDuplicatePacket = false;
             return;
         }
 
@@ -536,6 +564,11 @@ public void onPacketReceive(PacketReceiveEvent event) {
         // Such as the NoFall check setting the player to not be on the ground
         player.checkManager.onPacketReceive(event);
 
+        if (player.packetStateData.cancelDuplicatePacket) {
+            event.setCancelled(true);
+            player.packetStateData.cancelDuplicatePacket = false;
+        }
+
         // Finally, remove the packet state variables on this packet
         player.packetStateData.lastPacketWasOnePointSeventeenDuplicate = false;
         player.packetStateData.lastPacketWasTeleport = false;
@@ -667,6 +700,13 @@ private void handleFlying(GrimPlayer player, double x, double y, double z, float
             player.packetStateData.packetPlayerOnGround = onGround;
         }
 
+        if (!player.packetStateData.lastPacketWasOnePointSeventeenDuplicate) {
+            player.packetStateData.lastMovementWasDefinitelyOnePointSeventeenDuplicate = false;
+            if (!player.packetStateData.lastPacketWasTeleport) {
+                player.packetStateData.lastTeleportWasPotentiallyOnePointSeventeenDuplicate = false;
+            }
+        }
+
         if (hasLook) {
             player.xRot = yaw;
             player.yRot = pitch;

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketBlockAction.java b/src/main/java/ac/grim/grimac/events/packets/PacketBlockAction.java
@@ -20,7 +20,7 @@
 //
 public class PacketBlockAction extends PacketListenerAbstract {
     public PacketBlockAction() {
-        super(PacketListenerPriority.HIGH);
+        super(PacketListenerPriority.HIGHEST);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketConfigurationListener.java b/src/main/java/ac/grim/grimac/events/packets/PacketConfigurationListener.java
@@ -12,7 +12,7 @@
 public class PacketConfigurationListener extends PacketListenerAbstract {
 
     public PacketConfigurationListener() {
-        super(PacketListenerPriority.LOW);
+        super(PacketListenerPriority.NORMAL);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketEntityAction.java b/src/main/java/ac/grim/grimac/events/packets/PacketEntityAction.java
@@ -14,7 +14,7 @@
 public class PacketEntityAction extends PacketListenerAbstract {
 
     public PacketEntityAction() {
-        super(PacketListenerPriority.LOW);
+        super(PacketListenerPriority.NORMAL);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketPingListener.java b/src/main/java/ac/grim/grimac/events/packets/PacketPingListener.java
@@ -18,10 +18,9 @@ public class PacketPingListener extends PacketListenerAbstract {
 
     // Must listen on LOWEST (or maybe low) to stop Tuinity packet limiter from kicking players for transaction/pong spam
     public PacketPingListener() {
-        super(PacketListenerPriority.LOWEST);
+        super(PacketListenerPriority.LOW);
     }
 
-
     @Override
     public void onPacketReceive(PacketReceiveEvent event) {
         if (event.getPacketType() == PacketType.Play.Client.WINDOW_CONFIRMATION) {

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketPlayerAttack.java b/src/main/java/ac/grim/grimac/events/packets/PacketPlayerAttack.java
@@ -20,7 +20,7 @@
 public class PacketPlayerAttack extends PacketListenerAbstract {
 
     public PacketPlayerAttack() {
-        super(PacketListenerPriority.LOW);
+        super(PacketListenerPriority.NORMAL);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketPlayerCooldown.java b/src/main/java/ac/grim/grimac/events/packets/PacketPlayerCooldown.java
@@ -11,7 +11,7 @@
 public class PacketPlayerCooldown extends PacketListenerAbstract {
 
     public PacketPlayerCooldown() {
-        super(PacketListenerPriority.HIGH);
+        super(PacketListenerPriority.HIGHEST);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketPlayerDigging.java b/src/main/java/ac/grim/grimac/events/packets/PacketPlayerDigging.java
@@ -24,7 +24,7 @@
 public class PacketPlayerDigging extends PacketListenerAbstract {
 
     public PacketPlayerDigging() {
-        super(PacketListenerPriority.LOW);
+        super(PacketListenerPriority.NORMAL);
     }
 
     public static void handleUseItem(GrimPlayer player, ItemStack item, InteractionHand hand) {

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketPlayerRespawn.java b/src/main/java/ac/grim/grimac/events/packets/PacketPlayerRespawn.java
@@ -27,7 +27,7 @@
 public class PacketPlayerRespawn extends PacketListenerAbstract {
 
     public PacketPlayerRespawn() {
-        super(PacketListenerPriority.HIGH);
+        super(PacketListenerPriority.HIGHEST);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketPlayerSteer.java b/src/main/java/ac/grim/grimac/events/packets/PacketPlayerSteer.java
@@ -18,7 +18,7 @@
 public class PacketPlayerSteer extends PacketListenerAbstract {
 
     public PacketPlayerSteer() {
-        super(PacketListenerPriority.LOW);
+        super(PacketListenerPriority.NORMAL);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketSelfMetadataListener.java b/src/main/java/ac/grim/grimac/events/packets/PacketSelfMetadataListener.java
@@ -24,7 +24,7 @@
 
 public class PacketSelfMetadataListener extends PacketListenerAbstract {
     public PacketSelfMetadataListener() {
-        super(PacketListenerPriority.HIGH);
+        super(PacketListenerPriority.HIGHEST);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketServerTeleport.java b/src/main/java/ac/grim/grimac/events/packets/PacketServerTeleport.java
@@ -21,7 +21,7 @@
 public class PacketServerTeleport extends PacketListenerAbstract {
 
     public PacketServerTeleport() {
-        super(PacketListenerPriority.LOW);
+        super(PacketListenerPriority.NORMAL);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/PacketSetWrapperNull.java b/src/main/java/ac/grim/grimac/events/packets/PacketSetWrapperNull.java
@@ -25,7 +25,7 @@ public class PacketSetWrapperNull extends PacketListenerAbstract {
     // The two packets we change are clientbound entity metadata (to fix a netcode issue)
     // and the serverbound player flying packets (to patch NoFall)
     public PacketSetWrapperNull() {
-        super(PacketListenerPriority.HIGHEST);
+        super(PacketListenerPriority.MONITOR);
     }
 
     @Override

diff --git a/src/main/java/ac/grim/grimac/events/packets/patch/EnforceUseItemStupidity.java b/src/main/java/ac/grim/grimac/events/packets/patch/EnforceUseItemStupidity.java
@@ -0,0 +1,83 @@
+package ac.grim.grimac.events.packets.patch;
+
+import ac.grim.grimac.GrimAPI;
+import ac.grim.grimac.checks.impl.badpackets.BadPacketsU;
+import ac.grim.grimac.player.GrimPlayer;
+import com.github.retrooper.packetevents.PacketEvents;
+import com.github.retrooper.packetevents.event.PacketListenerAbstract;
+import com.github.retrooper.packetevents.event.PacketListenerPriority;
+import com.github.retrooper.packetevents.event.PacketReceiveEvent;
+import com.github.retrooper.packetevents.manager.server.ServerVersion;
+import com.github.retrooper.packetevents.protocol.packettype.PacketType;
+import com.github.retrooper.packetevents.protocol.player.ClientVersion;
+import com.github.retrooper.packetevents.protocol.world.BlockFace;
+import com.github.retrooper.packetevents.wrapper.play.client.WrapperPlayClientPlayerBlockPlacement;
+import com.github.retrooper.packetevents.wrapper.play.client.WrapperPlayClientPlayerFlying;
+
+// This runs before anything else, so this way we can simulate receiving flying.
+public class EnforceUseItemStupidity extends PacketListenerAbstract {
+
+    public EnforceUseItemStupidity() {
+        super(PacketListenerPriority.LOWEST);
+    }
+
+    @Override
+    public void onPacketReceive(PacketReceiveEvent event) {
+        GrimPlayer player = GrimAPI.INSTANCE.getPlayerDataManager().getPlayer(event.getUser());
+        if (player == null) return;
+
+        // Stupidity packet only exists on 1.17+
+        if (player.getClientVersion().isOlderThan(ClientVersion.V_1_17)) return;
+
+        final boolean wasPotentiallyOnePointSeventeenDuplicate = player.packetStateData.lastTeleportWasPotentiallyOnePointSeventeenDuplicate;
+        if (isUseItem(event)) {
+            player.packetStateData.lastTeleportWasPotentiallyOnePointSeventeenDuplicate = false;
+            if (!player.packetStateData.detectedStupidity && !wasPotentiallyOnePointSeventeenDuplicate) {
+                // The player MUST send a stupidity packet before use item
+                player.checkManager.getPacketCheck(BadPacketsU.class).flagAndAlert("type=skipped_stupid");
+                return;
+            }
+        }
+
+        player.packetStateData.lastTeleportWasPotentiallyOnePointSeventeenDuplicate = false;
+
+        // If we received a believed stupidity packet, the next packet MUST be USE_ITEM.
+        // If not, we were wrong or the client is attempting to fake stupidity.
+        if (player.packetStateData.detectedStupidity || wasPotentiallyOnePointSeventeenDuplicate) {
+            if (isUseItem(event)) {
+                // Valid stupidity packet.
+                player.packetStateData.detectedStupidity = false;
+
+                // Possibly delay this USE_ITEM packet.
+                player.checkManager.getPacketCheck(UseItemDelayer.class).addDelayed(event);
+
+                player.packetStateData.lastLastStupidity = player.packetStateData.lastStupidity;
+                player.packetStateData.lastStupidity = null;
+                player.packetStateData.lastMovementWasDefinitelyOnePointSeventeenDuplicate = true;
+//                Bukkit.broadcastMessage("valid stupidity packet");
+                return;
+            }
+
+            // Reset
+            player.packetStateData.detectedStupidity = false;
+            player.packetStateData.lastMovementWasDefinitelyOnePointSeventeenDuplicate = false;
+
+            // Let's ignore teleports
+            if (player.packetStateData.lastStupidity == null || wasPotentiallyOnePointSeventeenDuplicate) return; // Probably a teleport
+
+            // We were wrong about it being stupidity, or the client is attempting to fake stupidity, reprocess this packet as non-stupidity
+            player.packetStateData.ignoreDuplicatePacket = true;
+
+            PacketEvents.getAPI().getPlayerManager().receivePacket(player.bukkitPlayer, new WrapperPlayClientPlayerFlying(true, true, player.packetStateData.packetPlayerOnGround, player.packetStateData.lastStupidity));
+//            Bukkit.broadcastMessage("not stupidity");
+        }
+    }
+
+    private boolean isUseItem(PacketReceiveEvent event) {
+        // This is USE_ITEM but translated by via
+        if (PacketEvents.getAPI().getServerManager().getVersion().isOlderThan(ServerVersion.V_1_9) && event.getPacketType() == PacketType.Play.Client.PLAYER_BLOCK_PLACEMENT) {
+            return new WrapperPlayClientPlayerBlockPlacement(event).getFace() == BlockFace.OTHER;
+        }
+        return event.getPacketType() == PacketType.Play.Client.USE_ITEM;
+    }
+}