From d842c6192a5abf9b572893dc6b722d1f33cbef80 Mon Sep 17 00:00:00 2001
From: Wyatt <parsonswy@gmail.com>
Date: Wed, 17 Apr 2024 20:22:51 -0400
Subject: [PATCH] fix: binary parser sometimes reads out of packet bounds when
 results contain null and typecast is false

---
 lib/parsers/binary_parser.js | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/lib/parsers/binary_parser.js b/lib/parsers/binary_parser.js
index 5a08df7b7c..1083204f04 100644
--- a/lib/parsers/binary_parser.js
+++ b/lib/parsers/binary_parser.js
@@ -169,6 +169,10 @@ function compile(fields, options, config) {
       lvalue = `result[${fieldName}]`;
     }
 
+    parserFn(`if (nullBitmaskByte${nullByteIndex} & ${currentFieldNullBit}) `);
+    parserFn(`${lvalue} = null;`);
+    parserFn('else {');
+
     if (options.typeCast === false) {
       parserFn(`${lvalue} = packet.readLengthCodedBuffer();`);
     } else {
@@ -176,9 +180,6 @@ function compile(fields, options, config) {
       parserFn(`const ${fieldWrapperVar} = wrap(fields[${i}], packet);`);
       const readCode = readCodeFor(fields[i], config, options, i);
 
-      parserFn(`if (nullBitmaskByte${nullByteIndex} & ${currentFieldNullBit})`);
-      parserFn(`${lvalue} = null;`);
-      parserFn('else {');
       if (typeof options.typeCast === 'function') {
         parserFn(
           `${lvalue} = options.typeCast(${fieldWrapperVar}, function() { return ${readCode} });`,
@@ -186,8 +187,9 @@ function compile(fields, options, config) {
       } else {
         parserFn(`${lvalue} = ${readCode};`);
       }
-      parserFn('}');
     }
+    parserFn('}');
+
 
     currentFieldNullBit *= 2;
     if (currentFieldNullBit === 0x100) {