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NT Security Classes for .NET

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19 Feb 2004CPOL2 min read 375.7K   3.9K   75   103
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).

C#
// 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.

C#
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)


Written By
Chief Technology Officer
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

 
GeneralRe: problems accessing the security object Pin
David Hall20-Aug-02 8:47
professionalDavid Hall20-Aug-02 8:47 
GeneralRe: problems accessing the security object Pin
Syborg7722-Aug-02 22:54
Syborg7722-Aug-02 22:54 
GeneralVery interesting! Pin
serberwww29-Jul-02 21:20
serberwww29-Jul-02 21:20 
GeneralRe: Very interesting! Pin
David Hall30-Jul-02 4:39
professionalDavid Hall30-Jul-02 4:39 
GeneralRe: Very interesting! Pin
serberwww6-Aug-02 4:04
serberwww6-Aug-02 4:04 
GeneralRe: Very interesting! Pin
Yik Kheam30-Sep-02 14:46
sussYik Kheam30-Sep-02 14:46 
GeneralRe: Very interesting! Pin
John Horst16-Aug-02 8:57
John Horst16-Aug-02 8:57 
GeneralRe: Very interesting! Pin
John Horst16-Aug-02 9:00
John Horst16-Aug-02 9:00 
John Horst wrote:
Re: ASP.NET running under its own account.

You can enter the following in the Web.config file anywhere within the tag: (make sure "true" is all lower case).

This will cause the ASP.NET site to run under the identity of the person who logged in (this assumes that you set your site in IIS to authenticate the user).

John Horst


Some how part of my post was dropped. You add <identity impersonate="true"> under the <system.web> tag.

John
GeneralRe: Very interesting! Pin
John Horst16-Aug-02 9:03
John Horst16-Aug-02 9:03 
GeneralRe: Very interesting! Pin
David Hall16-Aug-02 9:06
professionalDavid Hall16-Aug-02 9:06 
GeneralRe: Very interesting! Pin
John Horst16-Aug-02 9:25
John Horst16-Aug-02 9:25 
GeneralRe: Very interesting! Pin
David Hall16-Aug-02 9:49
professionalDavid Hall16-Aug-02 9:49 
GeneralDoesn't compile (Link Error) Pin
Anonymous29-Jul-02 4:47
Anonymous29-Jul-02 4:47 
GeneralRe: Doesn't compile (Link Error) Pin
Michael Shaw30-Jul-02 17:05
Michael Shaw30-Jul-02 17:05 
QuestionImpersonate? Pin
Todd Smith25-Jul-02 11:45
Todd Smith25-Jul-02 11:45 
AnswerRe: Impersonate? Pin
David Hall25-Jul-02 11:51
professionalDavid Hall25-Jul-02 11:51 
QuestionA Fortune 20 company? Pin
-- Ed James --24-Jul-02 15:19
suss-- Ed James --24-Jul-02 15:19 
AnswerRe: A Fortune 20 company? Pin
Tim Smith24-Jul-02 15:51
Tim Smith24-Jul-02 15:51 

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