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NT Security Classes for .NET

, 19 Feb 2004
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A collection of .NET classes written in Managed C++ that faciliate the manipulation of NT security rights

Introduction

This class library allows access to the Win32 security calls in a .NET friendly way. It encapsulates the concepts of a user, a securable object (like a file, named pipe, directory, etc.), and permissions. This library was written in Managed C++ to simplify the amount of work needed to link to existing Win32 libraries. However, since it exposes all of its functionality via .NET, it can be used from any .NET compliant language, including C# and Visual Basic. The project was written and compiled with Visual Studio 2002.

NOTE: There is a library written by some Microsoft guys on GotDotNet that does much of the same thing and more. It can be found at http://www.gotdotnet.com/Community/UserSamples/Details.aspx?SampleGuid=e6098575-dda0-48b8-9abf-e0705af065d9.

This article outlines the primary objects in the library and their use in manipulating security objects.

Documentation

WindowsUser class

This class represents a single Windows identity (SID). It can be created by specifying either a username ("DOMAIN\user" format) or the string representation of a SID ("S-1-5-xxxx-xxx..."). You can also get the identity of the current user using the static property CurrentUser.

There are a number of predefined identities that exist as static members of a child class called WellKnownIdentities. Once you have an identity, you can get the following properties:

  • AccountName: string name of the account
  • Domain: string name of the account's domain
  • FullName: string in the form of "Domain\AccountName"
  • SidString: string representation of the SID

SecuredObject class

This class represents an object which can have a security descriptor. It can be created by specifying the name of the resource along with its type or by passing a handle (as an IntPtr) to the resource.

Once you have the object, you can update the permissions, audit information, owner and group.

PermissionsList

This class encapsulates actions on the ACL. It allows granting, revoking, changing, and denying access levels to different users. Derived from AccessList, which is a collection class for AccessEntry.

AuditingList

This class encapsulates actions on the auditing list of an object. It allows getting and setting audit success and failure rights. Derived from AccessList, which is a collection class for AccessEntry.

AccessEntry

This class encapsulates the Access Control Entry or ACE. You can set the user (trustee) and the associated rights and inheritance.

Example

This code shows the library in action. It assumes you have aliased the Microsoft.Win32.Security namespace (using in C#, Imports in VB).

// Get the current user and print their information
WindowsUser user = WindowsUser.CurrentUser;
Console.WriteLine("{0} ({1})", user.FullName, user.SidString);

// Get the current user from their token
WindowsUser duser = new WindowsUser(
  System.Security.Principal.WindowsIdentity.GetCurrent().Token);
Console.WriteLine(duser.FullName);

// Compare users
if (user == duser)
   Console.WriteLine("Same");
else
   Console.WriteLine("Different");

// Get a well-known user
user = WindowsUser.WellKnownIdentities.World;
Console.WriteLine(user.FullName);

// Get a user by name from a specific server (usually a domain controller)
WindowsUser kuser = new WindowsUser("user2", @"\\MYPDC");
Console.WriteLine(kuser.FullName);

// Get a user by name
user = new WindowsUser("DOMAIN\\user3");
Console.WriteLine(user.FullName);

// Get a user by SID
user = new WindowsUser("S-1-5-21-21782756-1035017279-1439700725-1111");
Console.WriteLine(user.FullName);

// Get security for C:\ directory
SecuredObject sec = new SecuredObject("C:\\", SecuredObjectType.FileObject);
DumpObject(sec);

// Set some various permissions on the directory
sec.Permissions.SetAccess(kuser, AccessRights.FileRead,
   AceInheritanceFlags.ContainerInherit|AceInheritanceFlags.ObjectInherit);
sec.Permissions.GrantAccess(kuser, AccessRights.FileExecute,
   AceInheritanceFlags.ContainerInherit|AceInheritanceFlags.ObjectInherit);
sec.Permissions.DenyAccess(kuser, AccessRights.FileWriteUnsync,
   AceInheritanceFlags.ContainerInherit|AceInheritanceFlags.ObjectInherit);
WindowsUser owner = sec.Owner;
sec.Owner = duser;
sec.Auditing.SetAuditFailure(duser, AccessRights.FileReadUnsync,
   AceInheritanceFlags.ContainerInherit|AceInheritanceFlags.ObjectInherit);
DumpObject(sec);

// Revoke some access
sec.Permissions.RevokeAccess(kuser);
sec.Owner = owner;
DumpObject(sec) ;

// Reset the security on the directory
sec.Permissions.Clear();
sec.Permissions.InheritFromParent = true;
DumpObject(sec);

// Write the DACL using the Microsoft style
Console.WriteLine(sec.ToString());

The following function shows how to enumerate the permissions on a security object.

static void DumpObject(SecuredObject sec)
{
   Console.WriteLine("Security description:");
   Console.WriteLine("=====================");
   Console.WriteLine("Owner: {0}\nGroup: {1}", 
     sec.Owner.FullName, sec.Group.FullName);
   Console.WriteLine("Permissions:");
   foreach (AccessEntry ace in sec.Permissions)
      Console.WriteLine(String.Format("  {0} : {1} : {2}", 
         ace.Trustee.FullName,
         ace.Inheritance, ace.Rights));
   Console.WriteLine("Auditing:");
   foreach (AccessEntry ace in sec.Auditing)
      Console.WriteLine(String.Format("  {0} : {1} : {2}", 
         ace.Trustee.FullName,
         ace.Inheritance, ace.Rights));
}

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

David Hall
Architect
United States United States
I have been a Windows software developer since 1991. Most of what I create fills the need for some aspect of bigger projects that I consult on.

Comments and Discussions

 
GeneralError while assigning SecurityObject PinmemberVikramSaraf30-May-05 21:07 
GeneralRe: Error while assigning SecurityObject PinmemberDavid Hall6-Jun-05 5:30 
GeneralNamed pipe help Pinmembererictaneda26-Dec-04 8:45 
GeneralQuestion about enums.h PinmemberJohn Rusk29-Nov-04 16:36 
David,
 
Thanks for posting this code, it's very useful.
 
I have taken over a long-running project that uses your code. Unfortunately, the original developer on this project is no longer available to answer questions. I have noticed that "our" version of the source code differs slightly from yours, and I'm wondering which is right.
 
In "ours", AceInheritanceFlags is of type Int16 and contains SUB_CONTAINERS_AND_OBJECTS_INHERIT. In the version currently on Code Project, AceInheritanceFlags is of type Byte, and does not contain SUB_CONTAINERS_AND_OBJECTS_INHERIT.
 
I'm not sure whether our version is out of date, or if the differences are bug fixes made by my predecessor. Given my description above, are you able to tell me which is correct?
 
Many thanks,
 
John
GeneralRe: Question about enums.h PinmemberDavid Hall30-Nov-04 4:51 
GeneralRe: Question about enums.h PinmemberJohn Rusk30-Nov-04 8:32 
GeneralAdds special permissions not regula permissions Pinmemberpatel_o19-Nov-04 4:54 
GeneralRe: Adds special permissions not regula permissions PinmemberDavid Hall19-Nov-04 5:08 
GeneralRe: Adds special permissions not regula permissions Pinmemberpatel_o19-Nov-04 8:36 
GeneralRe: Adds special permissions not regula permissions PinmemberDavid Hall7-Dec-04 7:07 

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