VPGATHER

Using the peculiar behaviour of the VPGATHER instructions to determine if an address will fault before it is truly accessed. All done in user-mode.

Usage Example

#include <Windows.h>
#include "Vpgather.h"

/**
 * @brief Program main subroutine
 * 
 * @param [in] Argc: The number of arguments supplied to the running program
 * @param [in] Argv: A pointer to a list of arguments supplied to the running program, including the name.
 */
LONG
main( 
	_In_ ULONG   Argc, 
	_In_ LPCSTR* Argv 
	)
{
	//
	// Initialize VPGATHER functionality if supported on the running system
	//
	if ( VpgInitialize( ) == FALSE )
    {
        return 0l;
    }

	//
	// This address should never be accessible
	//
	if ( VpgIsAddressAccessible( ( LPVOID )0x1333333333333337 ) == FALSE )
	{
		printf( "0x1333333333333337 is not accessible!\n" );
	}

	//
	// This address should be accessible
	//
	if ( VpgIsAddressAccessible( main ) == TRUE )
	{
		printf( "%p is accessible!\n", main );
	}

	return 0l;
}

Credits

Full credit to @sixtyvividtails for bringing this behavior to people's attention, including mine.