#include <Windows.h>

#include <array>
#include <iostream>

int main(int argc, char* argv[])
{
    std::array<unsigned char, 11> NtProtectVirtualMemoryBytes =
    {
        0x4C, 0x8B, 0xD1,               /*mov r10, rcx*/
        0xB8, 0x50, 0x00, 0x00, 0x00,   /*mov eax, 0x50*/
        0x0F, 0x05,                     /*syscall*/
        0xC3                            /*ret*/
    };

    auto* NtProtectVirtualMemoryStub{ VirtualAlloc(nullptr,
        NtProtectVirtualMemoryBytes.size(),
        MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE) };

    memcpy(NtProtectVirtualMemoryStub, NtProtectVirtualMemoryBytes.data(),
        NtProtectVirtualMemoryBytes.size());

    using NtProtectVirtualMemoryFnc = NTSTATUS(NTAPI*)(HANDLE, PVOID*, SIZE_T*, ULONG, PULONG);
    auto NtProtectVirtualMemory{
        reinterpret_cast<NtProtectVirtualMemoryFnc>(NtProtectVirtualMemoryStub) };

    SIZE_T allocSize = 4096;
    auto* testPage{ VirtualAlloc(nullptr, allocSize,
        MEM_RESERVE | MEM_COMMIT, PAGE_READONLY) };

    DWORD oldPermissions{};
    auto result{ NtProtectVirtualMemory(GetCurrentProcess(), &testPage, &allocSize,
        PAGE_EXECUTE_READWRITE, &oldPermissions) };

    std::cout << "Result: " << std::hex << result;

    auto* testWrite{ "Some bytes" };
    memcpy(testPage, testWrite, strlen(testWrite));
}