Mutex Permissions

[Kris]

I want to set a mutex in one windows account and allow another windows account to access this mutex.

For testing I have two forms that create a mutex using the C# mutex class. I am logging into Windows XP as "User1" and creating and locking the mutex from "User1" using the 1st form. I then use the "switch users" function to log in as "User2" and run the 2nd form and attempt to create the mutex (using the same name). When I try this I get access denied.

I have then tried to use the Win32 classes (as below) but still not working (same problem "access denied"). Any ideas?

namespace MyWin32API
{

// Required SecurityAttribu tes Structure LPSECURITY_ATTR IBUTES
[StructLayout(La youtKind.Sequen tial)]
public class SecurityAttribu tes
{
public int nLength = Marshal.SizeOf( typeof(Security Attributes));
public long lpSecurityDescr iptor;
public bool bInheritHandle;
}
public class CWin32
{

// Security Rights Constants - See Winnt.h
public const UInt32 SYNCHRONIZE = 0x00100000;
public const UInt32 STANDARD_RIGHTS _REQUIRED = 0x000F0000;
public const UInt32 MUTANT_QUERY_ST ATE = 0x0001;

// Security Rights Constants - See winbase.h and winnt.h
public static UInt32 MUTEX_ALL_ACCES S = (SYNCHRONIZE |
STANDARD_RIGHTS _REQUIRED | MUTANT_QUERY_ST ATE);
//CreateMutex
[DllImport("kern el32.dll", SetLastError=tr ue)]
private static extern UInt32 CreateMutex(Sec urityAttributes
lpMutexAttribut es, bool InitialOwner, string MutexName);

// Win 32 Masked Method - does not use return handle currently
public UInt32 Win32CreateMute x(bool InitialOwner, string MutexName)
{
SecurityAttribu tes sa = new SecurityAttribu tes();
sa.bInheritHand le = false;
sa.lpSecurityDe scriptor = CWin32.MUTEX_AL L_ACCESS;

return CWin32.CreateMu tex(sa,InitialO wner,MutexName) ;
}
}

Thank you,

Kris

[Willy Denoyette [MVP]]

You need to create a DACL containing an ACE's for all trustee's you want to
access the Mutex object, and set the DACL's address in the
SecurityAttribu tes lpSecurityDescr iptor member.

Willy.

"Kris" <an*******@disc ussions.microso ft.com> wrote in message
news:F8******** *************** ***********@mic rosoft.com...

I want to set a mutex in one windows account and allow another windows
account to access this mutex.

For testing I have two forms that create a mutex using the C# mutex class.
I am logging into Windows XP as "User1" and creating and locking the mutex
from "User1" using the 1st form. I then use the "switch users" function to
log in as "User2" and run the 2nd form and attempt to create the mutex
(using the same name). When I try this I get access denied.

I have then tried to use the Win32 classes (as below) but still not
working (same problem "access denied"). Any ideas?

namespace MyWin32API
{

// Required SecurityAttribu tes Structure LPSECURITY_ATTR IBUTES
[StructLayout(La youtKind.Sequen tial)]
public class SecurityAttribu tes
{
public int nLength = Marshal.SizeOf( typeof(Security Attributes));
public long lpSecurityDescr iptor;
public bool bInheritHandle;
}
public class CWin32
{

// Security Rights Constants - See Winnt.h
public const UInt32 SYNCHRONIZE = 0x00100000;
public const UInt32 STANDARD_RIGHTS _REQUIRED = 0x000F0000;
public const UInt32 MUTANT_QUERY_ST ATE = 0x0001;

// Security Rights Constants - See winbase.h and winnt.h
public static UInt32 MUTEX_ALL_ACCES S = (SYNCHRONIZE |
STANDARD_RIGHTS _REQUIRED | MUTANT_QUERY_ST ATE);
//CreateMutex
[DllImport("kern el32.dll", SetLastError=tr ue)]
private static extern UInt32 CreateMutex(Sec urityAttributes
lpMutexAttribut es, bool InitialOwner, string MutexName);

// Win 32 Masked Method - does not use return handle currently
public UInt32 Win32CreateMute x(bool InitialOwner, string MutexName)
{
SecurityAttribu tes sa = new SecurityAttribu tes();
sa.bInheritHand le = false;
sa.lpSecurityDe scriptor = CWin32.MUTEX_AL L_ACCESS;

return CWin32.CreateMu tex(sa,InitialO wner,MutexName) ;
}
}

Thank you,

Kris

[Willy Denoyette [MVP]]

You need to create a DACL containing an ACE's for all trustee's you want to
access the Mutex object, and set the DACL's address in the
SecurityAttribu tes lpSecurityDescr iptor member.

Willy.

"Kris" <an*******@disc ussions.microso ft.com> wrote in message
news:F8******** *************** ***********@mic rosoft.com...

I want to set a mutex in one windows account and allow another windows
account to access this mutex.

For testing I have two forms that create a mutex using the C# mutex class.
I am logging into Windows XP as "User1" and creating and locking the mutex
from "User1" using the 1st form. I then use the "switch users" function to
log in as "User2" and run the 2nd form and attempt to create the mutex
(using the same name). When I try this I get access denied.

I have then tried to use the Win32 classes (as below) but still not
working (same problem "access denied"). Any ideas?

namespace MyWin32API
{

// Required SecurityAttribu tes Structure LPSECURITY_ATTR IBUTES
[StructLayout(La youtKind.Sequen tial)]
public class SecurityAttribu tes
{
public int nLength = Marshal.SizeOf( typeof(Security Attributes));
public long lpSecurityDescr iptor;
public bool bInheritHandle;
}
public class CWin32
{

// Security Rights Constants - See Winnt.h
public const UInt32 SYNCHRONIZE = 0x00100000;
public const UInt32 STANDARD_RIGHTS _REQUIRED = 0x000F0000;
public const UInt32 MUTANT_QUERY_ST ATE = 0x0001;

// Security Rights Constants - See winbase.h and winnt.h
public static UInt32 MUTEX_ALL_ACCES S = (SYNCHRONIZE |
STANDARD_RIGHTS _REQUIRED | MUTANT_QUERY_ST ATE);
//CreateMutex
[DllImport("kern el32.dll", SetLastError=tr ue)]
private static extern UInt32 CreateMutex(Sec urityAttributes
lpMutexAttribut es, bool InitialOwner, string MutexName);

// Win 32 Masked Method - does not use return handle currently
public UInt32 Win32CreateMute x(bool InitialOwner, string MutexName)
{
SecurityAttribu tes sa = new SecurityAttribu tes();
sa.bInheritHand le = false;
sa.lpSecurityDe scriptor = CWin32.MUTEX_AL L_ACCESS;

return CWin32.CreateMu tex(sa,InitialO wner,MutexName) ;
}
}

Thank you,

Kris