Updated some broken projects, cleaned up example code, and remove old artifacts

Chapter8_ControlFlow/VFHookExample.cpp

@@ -0,0 +1,76 @@
+#include "main.h"
+
+// This is a dummy base-class
+class someBaseClass
+{
+	public:
+		virtual DWORD someFunction(DWORD arg1) { return 0; }
+};
+
+// This is the class for which we'll
+// actually hook the VF table. It inherits
+// the dummy base-class to ensure that
+// someFunction() is in a virtual table.
+class someClass : public someBaseClass
+{
+	public:
+		virtual DWORD someFunction(DWORD arg1)
+		{
+			if (arg1 == 1)
+				printf("    VF Table hook worked! Parameters intercepted and changed!\n");
+			else
+				printf("    VF Table hook failed!\n");
+			return 0;
+		}
+};
+
+
+// This is where we re-direct the VF calls to
+DWORD originalVFFunction;
+DWORD __stdcall someNewVFFunction(DWORD arg1)
+{
+	// notice how we take ECX and store it in a variable..
+	// this is done because it stores the class instance pointer ("this")
+	// and we want to make sure our code doesn't overwrite it (the compiler
+	// doesn't understand that this is a VF hook, so it may think ECX is 
+	// free for it to use)
+
+	static DWORD _this, _ret;
+	__asm MOV _this, ECX
+
+	printf("VFHook pre\n");
+	__asm {
+		PUSH 1
+		MOV ECX, _this
+		CALL [originalVFFunction]
+		MOV _ret, EAX
+	}
+	printf("VFHook Post\n");
+
+	__asm MOV ECX, _this
+	return _ret;
+}
+
+// This is the function that actually places the hook
+DWORD hookVF(DWORD classInst, DWORD funcIndex, DWORD newFunc)
+{
+	DWORD VFTable = readMemory<DWORD>(classInst);
+	DWORD hookAddress = VFTable + funcIndex * sizeof(DWORD);
+
+	auto oldProtection = protectMemory<DWORD>(hookAddress, PAGE_READWRITE);
+	DWORD originalFunc = readMemory<DWORD>(hookAddress);
+	writeMemory<DWORD>(hookAddress, newFunc);
+	protectMemory<DWORD>(hookAddress, oldProtection);
+
+	return originalFunc;
+}
+
+// This is the function that ties everything together
+void VFHookExample()
+{
+	someClass* inst = new someClass();
+
+	originalVFFunction = hookVF((DWORD)inst, 0, (DWORD)&someNewVFFunction);
+	inst->someFunction(0);
+	delete inst;
+}