fixed #498 - avoid potential leak in simplecpp::Macro::parseDefine() (#527)

Author: firewave

simplecpp.cpp

@@ -1709,7 +1709,9 @@ namespace simplecpp {
             nameTokDef = nametoken;
             variadic = false;
             variadicOpt = false;
+            delete optExpandValue;
             optExpandValue = nullptr;
+            delete optNoExpandValue;
             optNoExpandValue = nullptr;
             if (!nameTokDef) {
                 valueToken = endToken = nullptr;
@@ -2383,8 +2385,8 @@ namespace simplecpp {
         bool variadicOpt;
 
         /** Expansion value for varadic macros with __VA_OPT__ expanded and discarded respectively */
-        const TokenList *optExpandValue;
-        const TokenList *optNoExpandValue;
+        const TokenList *optExpandValue{};
+        const TokenList *optNoExpandValue{};
 
         /** was the value of this macro actually defined in the code? */
         bool valueDefinedInCode_;

test.cpp

@@ -3246,6 +3246,7 @@ static void safe_api()
 #endif
 }
 
+// crashes detected by fuzzer
 static void fuzz_crash()
 {
     {
@@ -3260,6 +3261,16 @@ static void fuzz_crash()
     }
 }
 
+// memory leaks detected by LSAN/valgrind
+static void leak()
+{
+    { // #498
+        const char code[] = "#define e(...)__VA_OPT__()\n"
+                            "#define e\n";
+        (void)preprocess(code, simplecpp::DUI());
+    }
+}
+
 int main(int argc, char **argv)
 {
     TEST_CASE(backslash);
@@ -3516,5 +3527,7 @@ int main(int argc, char **argv)
 
     TEST_CASE(fuzz_crash);
 
+    TEST_CASE(leak);
+
     return numberOfFailedAssertions > 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 }