TheCheatsrichter TheCheatsrichter - 3 months ago 27
C# Question

Close Handle after Duplicate

I was trying to close a handle to a Mutex of an extern process.
Therefore I tried to use DuplicateHandle from the Win32API as seen in this thread.

Closing the handle on the target process works. Closing it after duplicating it to my current process however does not. Strangely it also seems to duplicate the handle twice!

public class Win32API
{
[DllImport("ntdll.dll")]
public static extern int NtQueryObject(IntPtr ObjectHandle, int
ObjectInformationClass, IntPtr ObjectInformation, int ObjectInformationLength,
ref int returnLength);

[DllImport("kernel32.dll", SetLastError = true)]
public static extern uint QueryDosDevice(string lpDeviceName, StringBuilder lpTargetPath, int ucchMax);

[DllImport("ntdll.dll")]
public static extern uint NtQuerySystemInformation(int
SystemInformationClass, IntPtr SystemInformation, int SystemInformationLength,
ref int returnLength);

[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern IntPtr OpenMutex(UInt32 desiredAccess, bool inheritHandle, string name);

[DllImport("kernel32.dll")]
public static extern IntPtr OpenProcess(ProcessAccessFlags dwDesiredAccess, [MarshalAs(UnmanagedType.Bool)] bool bInheritHandle, int dwProcessId);

[DllImport("kernel32.dll")]
public static extern int CloseHandle(IntPtr hObject);

[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool DuplicateHandle(IntPtr hSourceProcessHandle,
ushort hSourceHandle, IntPtr hTargetProcessHandle, out IntPtr lpTargetHandle,
uint dwDesiredAccess, [MarshalAs(UnmanagedType.Bool)] bool bInheritHandle, uint dwOptions);

[DllImport("kernel32.dll")]
public static extern IntPtr GetCurrentProcess();

public enum ObjectInformationClass : int
{
ObjectBasicInformation = 0,
ObjectNameInformation = 1,
ObjectTypeInformation = 2,
ObjectAllTypesInformation = 3,
ObjectHandleInformation = 4
}

[Flags]
public enum ProcessAccessFlags : uint
{
All = 0x001F0FFF,
Terminate = 0x00000001,
CreateThread = 0x00000002,
VMOperation = 0x00000008,
VMRead = 0x00000010,
VMWrite = 0x00000020,
DupHandle = 0x00000040,
SetInformation = 0x00000200,
QueryInformation = 0x00000400,
Synchronize = 0x00100000
}

[StructLayout(LayoutKind.Sequential)]
public struct OBJECT_BASIC_INFORMATION
{ // Information Class 0
public int Attributes;
public int GrantedAccess;
public int HandleCount;
public int PointerCount;
public int PagedPoolUsage;
public int NonPagedPoolUsage;
public int Reserved1;
public int Reserved2;
public int Reserved3;
public int NameInformationLength;
public int TypeInformationLength;
public int SecurityDescriptorLength;
public System.Runtime.InteropServices.ComTypes.FILETIME CreateTime;
}

[StructLayout(LayoutKind.Sequential)]
public struct OBJECT_TYPE_INFORMATION
{ // Information Class 2
public UNICODE_STRING Name;
public int ObjectCount;
public int HandleCount;
public int Reserved1;
public int Reserved2;
public int Reserved3;
public int Reserved4;
public int PeakObjectCount;
public int PeakHandleCount;
public int Reserved5;
public int Reserved6;
public int Reserved7;
public int Reserved8;
public int InvalidAttributes;
public GENERIC_MAPPING GenericMapping;
public int ValidAccess;
public byte Unknown;
public byte MaintainHandleDatabase;
public int PoolType;
public int PagedPoolUsage;
public int NonPagedPoolUsage;
}

[StructLayout(LayoutKind.Sequential)]
public struct OBJECT_NAME_INFORMATION
{ // Information Class 1
public UNICODE_STRING Name;
}

[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct UNICODE_STRING
{
public ushort Length;
public ushort MaximumLength;
public IntPtr Buffer;
}

[StructLayout(LayoutKind.Sequential)]
public struct GENERIC_MAPPING
{
public int GenericRead;
public int GenericWrite;
public int GenericExecute;
public int GenericAll;
}

[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct SYSTEM_HANDLE_INFORMATION
{ // Information Class 16
public int ProcessID;
public byte ObjectTypeNumber;
public byte Flags; // 0x01 = PROTECT_FROM_CLOSE, 0x02 = INHERIT
public ushort Handle;
public int Object_Pointer;
public UInt32 GrantedAccess;
}

public const int MAX_PATH = 260;
public const uint STATUS_INFO_LENGTH_MISMATCH = 0xC0000004;
public const int DUPLICATE_SAME_ACCESS = 0x2;
public const int DUPLICATE_CLOSE_SOURCE = 0x1;
}

public class Win32Processes
{
const int CNST_SYSTEM_HANDLE_INFORMATION = 16;
const uint STATUS_INFO_LENGTH_MISMATCH = 0xc0000004;

public static string getObjectTypeName(Win32API.SYSTEM_HANDLE_INFORMATION shHandle, Process process)
{
IntPtr m_ipProcessHwnd = Win32API.OpenProcess(Win32API.ProcessAccessFlags.All, false, process.Id);
IntPtr ipHandle = IntPtr.Zero;
var objBasic = new Win32API.OBJECT_BASIC_INFORMATION();
IntPtr ipBasic = IntPtr.Zero;
var objObjectType = new Win32API.OBJECT_TYPE_INFORMATION();
IntPtr ipObjectType = IntPtr.Zero;
IntPtr ipObjectName = IntPtr.Zero;
string strObjectTypeName = "";
int nLength = 0;
int nReturn = 0;
IntPtr ipTemp = IntPtr.Zero;


if (!Win32API.DuplicateHandle(m_ipProcessHwnd, shHandle.Handle,
Win32API.GetCurrentProcess(), out ipHandle,
0, false, Win32API.DUPLICATE_SAME_ACCESS))
return null;

ipBasic = Marshal.AllocHGlobal(Marshal.SizeOf(objBasic));
Win32API.NtQueryObject(ipHandle, (int)Win32API.ObjectInformationClass.ObjectBasicInformation,
ipBasic, Marshal.SizeOf(objBasic), ref nLength);
objBasic = (Win32API.OBJECT_BASIC_INFORMATION)Marshal.PtrToStructure(ipBasic, objBasic.GetType());
Marshal.FreeHGlobal(ipBasic);

ipObjectType = Marshal.AllocHGlobal(objBasic.TypeInformationLength);
nLength = objBasic.TypeInformationLength;
while ((uint)(nReturn = Win32API.NtQueryObject(
ipHandle, (int)Win32API.ObjectInformationClass.ObjectTypeInformation, ipObjectType,
nLength, ref nLength)) ==
Win32API.STATUS_INFO_LENGTH_MISMATCH)
{
Marshal.FreeHGlobal(ipObjectType);
ipObjectType = Marshal.AllocHGlobal(nLength);
}

objObjectType = (Win32API.OBJECT_TYPE_INFORMATION)Marshal.PtrToStructure(ipObjectType, objObjectType.GetType());
if (Is64Bits())
{
ipTemp = new IntPtr(Convert.ToInt64(objObjectType.Name.Buffer.ToString(), 10) >> 32);
}
else
{
ipTemp = objObjectType.Name.Buffer;
}

strObjectTypeName = Marshal.PtrToStringUni(ipTemp, objObjectType.Name.Length >> 1);
Marshal.FreeHGlobal(ipObjectType);
return strObjectTypeName;
}


public static string getObjectName(Win32API.SYSTEM_HANDLE_INFORMATION shHandle, Process process)
{
IntPtr m_ipProcessHwnd = Win32API.OpenProcess(Win32API.ProcessAccessFlags.All, false, process.Id);
IntPtr ipHandle = IntPtr.Zero;
var objBasic = new Win32API.OBJECT_BASIC_INFORMATION();
IntPtr ipBasic = IntPtr.Zero;
IntPtr ipObjectType = IntPtr.Zero;
var objObjectName = new Win32API.OBJECT_NAME_INFORMATION();
IntPtr ipObjectName = IntPtr.Zero;
string strObjectName = "";
int nLength = 0;
int nReturn = 0;
IntPtr ipTemp = IntPtr.Zero;

if (!Win32API.DuplicateHandle(m_ipProcessHwnd, shHandle.Handle, Win32API.GetCurrentProcess(),
out ipHandle, 0, false, Win32API.DUPLICATE_SAME_ACCESS))
return null;

ipBasic = Marshal.AllocHGlobal(Marshal.SizeOf(objBasic));
Win32API.NtQueryObject(ipHandle, (int)Win32API.ObjectInformationClass.ObjectBasicInformation,
ipBasic, Marshal.SizeOf(objBasic), ref nLength);
objBasic = (Win32API.OBJECT_BASIC_INFORMATION)Marshal.PtrToStructure(ipBasic, objBasic.GetType());
Marshal.FreeHGlobal(ipBasic);


nLength = objBasic.NameInformationLength;

ipObjectName = Marshal.AllocHGlobal(nLength);
while ((uint)(nReturn = Win32API.NtQueryObject(
ipHandle, (int)Win32API.ObjectInformationClass.ObjectNameInformation,
ipObjectName, nLength, ref nLength))
== Win32API.STATUS_INFO_LENGTH_MISMATCH)
{
Marshal.FreeHGlobal(ipObjectName);
ipObjectName = Marshal.AllocHGlobal(nLength);
}
objObjectName = (Win32API.OBJECT_NAME_INFORMATION)Marshal.PtrToStructure(ipObjectName, objObjectName.GetType());

if (Is64Bits())
{
ipTemp = new IntPtr(Convert.ToInt64(objObjectName.Name.Buffer.ToString(), 10) >> 32);
}
else
{
ipTemp = objObjectName.Name.Buffer;
}

if (ipTemp != IntPtr.Zero)
{

byte[] baTemp2 = new byte[nLength];
try
{
Marshal.Copy(ipTemp, baTemp2, 0, nLength);

strObjectName = Marshal.PtrToStringUni(Is64Bits() ?
new IntPtr(ipTemp.ToInt64()) :
new IntPtr(ipTemp.ToInt32()));
return strObjectName;
}
catch (AccessViolationException)
{
return null;
}
finally
{
Marshal.FreeHGlobal(ipObjectName);
Win32API.CloseHandle(ipHandle);
}
}
return null;
}

public static List<Win32API.SYSTEM_HANDLE_INFORMATION>
GetHandles(Process process = null, string IN_strObjectTypeName = null, string IN_strObjectName = null)
{
uint nStatus;
int nHandleInfoSize = 0x10000;
IntPtr ipHandlePointer = Marshal.AllocHGlobal(nHandleInfoSize);
int nLength = 0;
IntPtr ipHandle = IntPtr.Zero;

while ((nStatus = Win32API.NtQuerySystemInformation(CNST_SYSTEM_HANDLE_INFORMATION, ipHandlePointer,
nHandleInfoSize, ref nLength)) ==
STATUS_INFO_LENGTH_MISMATCH)
{
nHandleInfoSize = nLength;
Marshal.FreeHGlobal(ipHandlePointer);
ipHandlePointer = Marshal.AllocHGlobal(nLength);
}

byte[] baTemp = new byte[nLength];
Marshal.Copy(ipHandlePointer, baTemp, 0, nLength);

long lHandleCount = 0;
if (Is64Bits())
{
lHandleCount = Marshal.ReadInt64(ipHandlePointer);
ipHandle = new IntPtr(ipHandlePointer.ToInt64() + 8);
}
else
{
lHandleCount = Marshal.ReadInt32(ipHandlePointer);
ipHandle = new IntPtr(ipHandlePointer.ToInt32() + 4);
}

Win32API.SYSTEM_HANDLE_INFORMATION shHandle;
List<Win32API.SYSTEM_HANDLE_INFORMATION> lstHandles = new List<Win32API.SYSTEM_HANDLE_INFORMATION>();

for (long lIndex = 0; lIndex < lHandleCount; lIndex++)
{
shHandle = new Win32API.SYSTEM_HANDLE_INFORMATION();
if (Is64Bits())
{
shHandle = (Win32API.SYSTEM_HANDLE_INFORMATION)Marshal.PtrToStructure(ipHandle, shHandle.GetType());
ipHandle = new IntPtr(ipHandle.ToInt64() + Marshal.SizeOf(shHandle) + 8);
}
else
{
ipHandle = new IntPtr(ipHandle.ToInt64() + Marshal.SizeOf(shHandle));
shHandle = (Win32API.SYSTEM_HANDLE_INFORMATION)Marshal.PtrToStructure(ipHandle, shHandle.GetType());
}

if (process != null)
{
if (shHandle.ProcessID != process.Id) continue;
}

string strObjectTypeName = "";
if (IN_strObjectTypeName != null)
{
strObjectTypeName = getObjectTypeName(shHandle, Process.GetProcessById(shHandle.ProcessID));
if (strObjectTypeName != IN_strObjectTypeName) continue;
}

string strObjectName = "";
if (IN_strObjectName != null)
{
strObjectName = getObjectName(shHandle, Process.GetProcessById(shHandle.ProcessID));
if (strObjectName != IN_strObjectName) continue;
}

string strObjectTypeName2 = getObjectTypeName(shHandle, Process.GetProcessById(shHandle.ProcessID));
string strObjectName2 = getObjectName(shHandle, Process.GetProcessById(shHandle.ProcessID));
MessageBox.Show(shHandle.ProcessID.ToString() + "\n" +strObjectTypeName2.ToString() + "\n" + strObjectName2.ToString());

lstHandles.Add(shHandle);
}
return lstHandles;
}

public static bool Is64Bits()
{
return Marshal.SizeOf(typeof(IntPtr)) == 8 ? true : false;
}
}

class MutexCloser
{
public void CloseMutex(string ProcessName, string MutexName)
{

try
{
Process process = Process.GetProcessesByName(ProcessName)[0];
var handles = Win32Processes.GetHandles(process, "Mutant", "\\Sessions\\1\\BaseNamedObjects\\" + MutexName);
if (handles.Count == 0) throw new System.ArgumentException("NoMutex", "original");
foreach (var handle in handles)
{
IntPtr ipHandle = IntPtr.Zero;
Win32API.DuplicateHandle(Process.GetProcessById(handle.ProcessID).Handle, handle.Handle, Win32API.GetCurrentProcess(), out ipHandle, 0, false, Win32API.DUPLICATE_CLOSE_SOURCE);
Win32API.CloseHandle(ipHandle);
MessageBox.Show("Mutex was killed");
}
}
catch (IndexOutOfRangeException)
{
MessageBox.Show("The process name '{0}' is not currently running", ProcessName);
}
catch (ArgumentException)
{
MessageBox.Show("The Mutex " + MutexName + " was not found in the process " + ProcessName);
}
}
}


Am I using the wrong Handle IP here?

IntPtr ipHandle = IntPtr.Zero;
Win32API.DuplicateHandle(Process.GetProcessById(handle.ProcessID).Handle, handle.Handle, Win32API.GetCurrentProcess(), out ipHandle, 0, false, Win32API.DUPLICATE_CLOSE_SOURCE);
Win32API.CloseHandle(ipHandle);


My target process is a 64-bit applicaton.

EDIT: Just to clarify. I want to close the duplicated handle or if somebody has an idea for a simplified version of closing a handle on another process.

Answer

You have a handle leak: getObjectTypeName() function duplicates the handle it is passed but never closes the duplicate.

That extra handle will be keeping the mutex alive, even though the target process no longer has a handle to it.

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