From d769264e252e3703f3ad2ab6cea03542084d237a Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Sat, 13 Jul 2024 17:01:35 -0500
Subject: [PATCH] fix possible hang when loading invalid MA/Ox feat

in instrument

issue #2021
---
 src/engine/instrument.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/engine/instrument.cpp b/src/engine/instrument.cpp
index d6407ec6c..ad5ebe8e1 100644
--- a/src/engine/instrument.cpp
+++ b/src/engine/instrument.cpp
@@ -1490,6 +1490,12 @@ void DivInstrument::readFeatureMA(SafeReader& reader, short version) {
 
   unsigned short macroHeaderLen=reader.readS();
 
+  if (macroHeaderLen==0) {
+    logW("invalid macro header length!");
+    READ_FEAT_END;
+    return;
+  }
+
   DivInstrumentMacro* target=&std.volMacro;
 
   while (reader.tell()<endOfFeat) {
@@ -1716,6 +1722,12 @@ void DivInstrument::readFeatureOx(SafeReader& reader, int op, short version) {
 
   unsigned short macroHeaderLen=reader.readS();
 
+  if (macroHeaderLen==0) {
+    logW("invalid macro header length!");
+    READ_FEAT_END;
+    return;
+  }
+
   DivInstrumentMacro* target=&std.opMacros[op].amMacro;
 
   while (reader.tell()<endOfFeat) {