#include "stdafx.h"
#include <cstdio>
#include <string>
#include <sstream>
#include <iostream>
#include <vector>
#include <windows.h>

using namespace std;

size_t GetSize(string p_sFilename)
{
    size_t size;
    FILE* f = fopen(p_sFilename.c_str(), "rb");

    // Get file size

    fseek(f, 0, SEEK_END);
    size = ftell(f);
    rewind(f);
    fclose(f);

    return size;
}

bool FileExists(string p_sPath)
{
    DWORD dwAttrib = GetFileAttributesA(p_sPath.c_str());

    return (dwAttrib != INVALID_FILE_ATTRIBUTES);
}

unsigned char* ReadBinaryFile(string p_sFilename, size_t *p_rSize)
{
    unsigned char *p = NULL;
    FILE* f = NULL;
    size_t res = 0;

    if (!FileExists(p_sFilename))
    {
        cout << "Binary file does not exists!" << endl;
        return NULL;
    }

    // Get size and allocate space

    *p_rSize = GetSize(p_sFilename);
    if (*p_rSize == 0) return NULL;

    f = fopen(p_sFilename.c_str(), "rb");

    p = new unsigned char[*p_rSize];

    // Read file

    rewind(f);
    res = fread(p, sizeof(unsigned char), *p_rSize, f);
    fclose(f);

    if (res == 0)
    {
        delete[] p;
        return NULL;
    }

    return p;
}

void TestShellcode(string p_sFilename)
{
    unsigned char *p = NULL;
    size_t size = 0;

    p = ReadBinaryFile(p_sFilename, &size);

    // Check if successful read

    if (size == 0 || p == NULL)
    {
        cout << "Error: Cannot read shellcode file!" << endl;
        return;
    }

    // Get space for shellcode

    void *sc = VirtualAlloc(0, size, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);

    if (sc == NULL)
    {
        cout << "Error: Cannot allocate space for shellcode!" << endl;
        return;
    }

    // Copy shellcode and execute it

    memcpy(sc, p, size);
    (*(int(*)()) sc)();
}


int main(int argc, char *argv[])
{
    TestShellcode(argv[1]);
    return 0;
}