fix: binary parser sometimes reads out of packet bounds when results …

…contain null and typecast is false
sidorares · Apr 18, 2024 · d842c61 · d842c61
1 parent 2129818
commit d842c61
Showing 1 changed file with 6 additions and 4 deletions.
diff --git a/lib/parsers/binary_parser.js b/lib/parsers/binary_parser.js
@@ -169,25 +169,27 @@ function compile(fields, options, config) {
       lvalue = `result[${fieldName}]`;
     }
 
+    parserFn(`if (nullBitmaskByte${nullByteIndex} & ${currentFieldNullBit}) `);
+    parserFn(`${lvalue} = null;`);
+    parserFn('else {');
+
     if (options.typeCast === false) {
       parserFn(`${lvalue} = packet.readLengthCodedBuffer();`);
     } else {
       const fieldWrapperVar = `fieldWrapper${i}`;
       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 ${readCode} });`,
         );
       } else {
         parserFn(`${lvalue} = ${readCode};`);
       }
-      parserFn('}');
     }
+    parserFn('}');
+
 
     currentFieldNullBit *= 2;
     if (currentFieldNullBit === 0x100) {