add original source

source/listing_3.2.cpp

@@ -0,0 +1,44 @@
+#include <mutex>
+
+class some_data
+{
+    int a;
+    std::string b;
+public:
+    void do_something()
+    {}
+};
+
+class data_wrapper
+{
+private:
+    some_data data;
+    std::mutex m;
+public:
+    template<typename Function>
+    void process_data(Function func)
+    {
+        std::lock_guard<std::mutex> l(m);
+        func(data);
+    }
+};
+
+some_data* unprotected;
+
+void malicious_function(some_data& protected_data)
+{
+    unprotected=&protected_data;
+}
+
+data_wrapper x;
+
+void foo()
+{
+    x.process_data(malicious_function);
+    unprotected->do_something();
+}
+
+int main()
+{
+    foo();
+}