From eac82f3c014aeef04da770a490e92c5fc71dc86a Mon Sep 17 00:00:00 2001
From: Melledy <52122272+Melledy@users.noreply.github.com>
Date: Sat, 30 Apr 2022 22:51:21 -0700
Subject: [PATCH] Fix possible exploit with mcoin exchange

---
 .../server/packet/recv/HandlerMcoinExchangeHcoinReq.java   | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/main/java/emu/grasscutter/server/packet/recv/HandlerMcoinExchangeHcoinReq.java b/src/main/java/emu/grasscutter/server/packet/recv/HandlerMcoinExchangeHcoinReq.java
index 0f3d2e7f8..57ecaf42b 100644
--- a/src/main/java/emu/grasscutter/server/packet/recv/HandlerMcoinExchangeHcoinReq.java
+++ b/src/main/java/emu/grasscutter/server/packet/recv/HandlerMcoinExchangeHcoinReq.java
@@ -13,14 +13,15 @@ public class HandlerMcoinExchangeHcoinReq extends PacketHandler {
     @Override
     public void handle(GameSession session, byte[] header, byte[] payload) throws Exception {
         McoinExchangeHcoinReqOuterClass.McoinExchangeHcoinReq exchangeReq = McoinExchangeHcoinReqOuterClass.McoinExchangeHcoinReq.parseFrom(payload);
-        if (session == null) {
-            return;
-        } else if (session.getPlayer().getCrystals() < exchangeReq.getMCoinNum()) {
+        
+        if (session.getPlayer().getCrystals() < exchangeReq.getMCoinNum() && exchangeReq.getMCoinNum() == exchangeReq.getHCoinNum()) {
             return;
         }
+        
         session.getPlayer().setCrystals(session.getPlayer().getCrystals() - exchangeReq.getMCoinNum());
         session.getPlayer().setPrimogems(session.getPlayer().getPrimogems() + exchangeReq.getHCoinNum());
         session.getPlayer().save();
+        
         session.send(new PacketMcoinExchangeHcoinRsp(session.getPlayer().getCrystals(), session.getPlayer().getPrimogems()));
     }
 }