WindowsVersionTroll (Compatibility Tool)

[jay]

This is a very basic utility that modifies the NT headers of an application to make it run on older Windows versions than it was designed for.
It will NOT fix compatibility issues caused by unavailable APIs. The only thing it will do is trick the Windows loader into running the newer application.

Usage: winvertroll.exe <target executable> [optional major version] [optional minor version, must be supplied if major is supplied]

If major and minor version are not supplied, the application will use 4 as the major version and 0 as the minor version. It's probably best to use it this way unless you have to have a very specific version for some bizarre reason.

winvertroll.exe

Executable of the tool

(10 KiB) Downloaded 40 times

CODE:

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Code: Select all

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

#define PARAM_COUNT 3
#define WORD_MAX 65535

int main(int argc, char** argv)
{
	int iMajorVersionInteger = 4;
	int iMinorVersionInteger = 0;

	if (argc != 2 && argc != (1 + PARAM_COUNT))
	{
		printf("Usage: winvertroll <filename> [major version as WORD] [minor version as WORD]\n");
		printf("If the major version is an invalid WORD, execution will fail. If the minor version is an invalid WORD, 0 will be assumed.\n");
		return -1;
	}

	if (argc > 2)
	{
		iMajorVersionInteger = atoi(argv[2]);
		iMinorVersionInteger = atoi(argv[3]);
	}

	// Check if the user is an idiot
	if (iMajorVersionInteger <= 0 || iMajorVersionInteger > WORD_MAX)
	{
		printf("Major version was not a valid WORD. Values may range from 1 to %i. (0 is valid but not allowed)\n", WORD_MAX);
		return -5;
	}

	if (iMinorVersionInteger < 0 || iMinorVersionInteger > WORD_MAX)
	{
		printf("Minor version was not a WORD. Values may range from 1 to %i.\n", WORD_MAX);
		return -6;
	}

	WORD wMajorVersion = (WORD)iMajorVersionInteger;
	WORD wMinorVersion = (WORD)iMinorVersionInteger;

	// Load file
	if ((GetFileAttributesA(argv[1]) != INVALID_FILE_ATTRIBUTES &&
		!(GetFileAttributesA(argv[1]) & FILE_ATTRIBUTE_DIRECTORY)))
	{
		// Open file for reading
		HANDLE hFile = CreateFileA(argv[1], GENERIC_READ, 0, NULL, OPEN_EXISTING, NULL, NULL);

		if (hFile)
		{
			DWORD dwFileSize;
			DWORD dwFileSizeHighYouProbablyWontNeedThisLmao;

			dwFileSize = GetFileSize(hFile, &dwFileSizeHighYouProbablyWontNeedThisLmao);
			CHAR* pBuffer = malloc(dwFileSize);

			if (pBuffer)
			{
				DWORD dwBytesRead;
				ReadFile(hFile, pBuffer, dwFileSize, &dwBytesRead, NULL);

				// Header troll
				PIMAGE_DOS_HEADER pDosHeader = (PIMAGE_DOS_HEADER)pBuffer;
				PIMAGE_NT_HEADERS32 pNTHeaders = (PIMAGE_NT_HEADERS)((DWORD)pBuffer + pDosHeader->e_lfanew);

				pNTHeaders->OptionalHeader.MajorOperatingSystemVersion = wMajorVersion;
				pNTHeaders->OptionalHeader.MinorOperatingSystemVersion = wMinorVersion;
				pNTHeaders->OptionalHeader.MajorSubsystemVersion = wMajorVersion;
				pNTHeaders->OptionalHeader.MinorSubsystemVersion = wMinorVersion;

				// Close file for reading, reopen for writing, if you don't think this is best practices then idk cry (comment revised for professionalism)
				CloseHandle(hFile);
				hFile = CreateFileA(argv[1], GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, NULL, NULL);

				if (hFile)
				{
					DWORD dwBytesWritten;
					WriteFile(hFile, pBuffer, dwFileSize, &dwBytesWritten, NULL);
					free(pBuffer);
					CloseHandle(hFile);

					printf("Success.\n");
					return 0;
				}
				else
				{
					free(pBuffer);
					return -4;
				}
			}
			else
			{
				CloseHandle(hFile);
				return -3;
			}
		}
		else
			return -2;
	}
}