Using undocumented classes in C ++

Question

I am reverse engineering a Windows executable. I found a class that I want to use from some code that I insert into the executable (another thread, own stack). How can I declare such a class, given the addresses of methods and the structure of member variables?

For example, let's say I found a class called foo, with it the constructor @ 0x4012D30 and the function doTheMario @ 40125D4. I also know that it contains three private data DWORDs. Since both methods are common, I declare such a class in my code:

class GuessedFoo {
    private:
        int bar;
        char *cafebabe;
        float deadbeef;
    public:
        GuessedFoo(int a, int b);
        void doTheMario();
};

Now, this class is great dandy, but is there now a way to get the compiler / linker to bind class methods to the two previous addresses that I have outlined? Of course, I can write an asm shell to convert stdcall to thiscall for each method I need to use, and then use structures instead of classes, but there should be a better way.

I am using gcc / g ++ at the moment, but I can switch to VC ++ (since gcc inline asm gives me headaches).

Answer 1

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Answer 2

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void main()
{
    int bar = 5;
    int * cafebabe = &bar;
    __asm
    {
        push [bar];
        push [cafebabe];
        mov eax, 123456; // address of the function
        call eax;
    }
}

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Answer 3

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Answer 4

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