#include "ntddk.h"

typedef struct ServiceDescriptorEntry {
	unsigned int *ServiceTableBase;
	unsigned int *ServiceCounterTableBase;
	unsigned int NumberOfServices;
	unsigned char *ParamTableBase;
} ServiceDescriptorTableEntry_t, *PServiceDescriptorTableEntry_t;

__declspec(dllimport) ServiceDescriptorTableEntry_t KeServiceDescriptorTable;
#define SYSTEMSERVICE(_function)KeServiceDescriptorTable.ServiceTableBase[ *(PULONG)((PUCHAR)_function+1)]

int typedef DWORD (ULONG);
PMDL g_pmdlSystemCall;
PVOID *MappedSystemCallTable;

#define SYSCALL_INDEX(_Function) *(PULONG)((PUCHAR)_Function+1)
#define HOOK_SYSCALL(_Function, _Hook, _Orig )_Orig = (PVOID) InterlockedExchange( (PLONG)&MappedSystemCallTable[SYSCALL_INDEX(_Function)], (LONG)_Hook)
#define UNHOOK_SYSCALL(_Function, _Hook, _Orig )InterlockedExchange( (PLONG)&MappedSystemCallTable[SYSCALL_INDEX(_Function)], (LONG)_Hook)

//Declaramos la API para poder trabajar con ella.
NTSYSAPI NTSTATUS NTAPI ZwOpenProcess (OUT PHANDLE ProcessHandle,IN ACCESS_MASK DesiredAccess,IN POBJECT_ATTRIBUTES ObjectAttributes,IN PCLIENT_ID ClientId OPTIONAL);
typedef NTSTATUS (*TypZwOpenProc)(OUT PHANDLE ProcessHandle,IN ACCESS_MASK DesiredAccess,IN POBJECT_ATTRIBUTES ObjectAttributes,IN PCLIENT_ID ClientId OPTIONAL);
TypZwOpenProc ZwOpenProcessIni;

void ObternerRuta( int pid );

NTSTATUS NewZwOpenProcess(OUT PHANDLE ProcessHandle,IN ACCESS_MASK DesiredAccess,IN POBJECT_ATTRIBUTES ObjectAttributes,IN PCLIENT_ID ClientId OPTIONAL)
{
	HANDLE PID;
	__try //Utilizamos el bloque try para evitar BSOD
	{
		PID = ClientId->UniqueProcess;
	}
	__except(EXCEPTION_EXECUTE_HANDLER)
	{
		return STATUS_INVALID_PARAMETER;
	}

	DbgPrint("PID: 0x%x",PID);
//CORREGÍ UN ERROR ACÁ :P
	if (ObternerRuta(PID)== "C:\\miprograma.exe") return
		STATUS_ACCESS_DENIED; //Retornamos acceso denegado
	else
		return ZwOpenProcessIni(ProcessHandle,DesiredAccess,ObjectAttributes, ClientId); //Llamamos a la API nativa y retornamos el resultado correcto
}

VOID OnUnload(IN PDRIVER_OBJECT DriverObject)
{
	DbgPrint("Descargando driver...");

	//Unhookeamos
	UNHOOK_SYSCALL( ZwOpenProcess, ZwOpenProcessIni, NewZwOpenProcess );

	//Eliminamos la MDL
	if(g_pmdlSystemCall)
	{
		MmUnmapLockedPages(MappedSystemCallTable, g_pmdlSystemCall);
		IoFreeMdl(g_pmdlSystemCall);
	}
}

NTSTATUS DriverEntry(IN PDRIVER_OBJECT DriverObject, IN PUNICODE_STRING theRegistryPath)
{
	DriverObject->DriverUnload = OnUnload;
	DbgPrint("Driver cargado");
	ZwOpenProcessIni =(TypZwOpenProc)(SYSTEMSERVICE(ZwOpenProcess));

	//Creamos la MDL para deshabilitar la protección de memoria
	g_pmdlSystemCall = MmCreateMdl(NULL, KeServiceDescriptorTable.ServiceTableBase, KeServiceDescriptorTable.NumberOfServices*4);
	if(!g_pmdlSystemCall)
		return STATUS_UNSUCCESSFUL;

	MmBuildMdlForNonPagedPool(g_pmdlSystemCall);
	g_pmdlSystemCall->MdlFlags = g_pmdlSystemCall->MdlFlags | MDL_MAPPED_TO_SYSTEM_VA;
	MappedSystemCallTable = (PVOID*)MmMapLockedPages(g_pmdlSystemCall, KernelMode);
	DbgPrint("Hookeando...");
	HOOK_SYSCALL( ZwOpenProcess, NewZwOpenProcess, ZwOpenProcessIni );

	return STATUS_SUCCESS;
}

void ObternerRuta( int pid )
{
	//AQUÍ ME FALTA CÓDIGO
}