RegistryKey.SetAccessControl(RegistrySecurity) Method

Definition

Namespace:

Microsoft.Win32

Assembly:

Microsoft.Win32.Registry.dll

Applies Windows access control security to an existing registry key.

public:
 void SetAccessControl(System::Security::AccessControl::RegistrySecurity ^ registrySecurity);

public void SetAccessControl (System.Security.AccessControl.RegistrySecurity registrySecurity);

member this.SetAccessControl : System.Security.AccessControl.RegistrySecurity -> unit

Public Sub SetAccessControl (registrySecurity As RegistrySecurity)

Parameters

registrySecurity

RegistrySecurity

The access control security to apply to the current subkey.

Exceptions

UnauthorizedAccessException

The current RegistryKey object represents a key with access control security, and the caller does not have ChangePermissions rights.

ArgumentNullException

registrySecurity is null.

ObjectDisposedException

The RegistryKey being manipulated is closed (closed keys cannot be accessed).

Examples

The following code example creates a test key. The current user is allowed ReadKey and Delete rights but denied ChangePermissions and WriteKey rights. Subsequent attempts to manipulate the key succeed or fail depending on these permissions.

Before the key is deleted, the code pauses. You can switch to the registry editor and verify that the same access rights apply when the key is accessed using the registry editor. (This works best if you use RunAs from the command line to run the registry editor and the sample code as a local user without administrator rights. The registry editor always allows an administrator to change permissions, even if the particular administrator has been denied those rights. If you have defined a local user named TestUser, the command runas /user:TestUser cmd opens a command window from which you can run the registry editor and then the sample code.)

using namespace System;
using namespace System::Reflection;
using namespace Microsoft::Win32;
using namespace System::Security::AccessControl;
using namespace System::Security;

int main()
{
    // Delete the example key if it exists.
    try
    {
        Registry::CurrentUser->DeleteSubKey("RegistryRightsExample");
        Console::WriteLine("Example key has been deleted.");
    }
    catch (ArgumentException^)
    {
        // ArgumentException is thrown if the key does not exist. In
        // this case, there is no reason to display a message.
    }
    catch (InvalidOperationException^ ex)
    {
        Console::WriteLine(
            "{0}Unable to delete key: it appears to have child subkeys:{0}{1}", 
            Environment::NewLine, ex);
        return 0;
    }
    catch (SecurityException^ ex)
    {
        Console::WriteLine("{0}You do not have the permissions required " +
            "to delete this key:{0}{1}", Environment::NewLine, ex);
        return 0;
    }

    String^ user = Environment::UserDomainName + "\\" + Environment::UserName;

    RegistrySecurity^ regSecurity = gcnew RegistrySecurity();

    // Allow the current user to read and delete the key.
    //
    regSecurity->AddAccessRule(gcnew RegistryAccessRule(user,
        RegistryRights::ReadKey | RegistryRights::Delete,
        InheritanceFlags::None,
        PropagationFlags::None,
        AccessControlType::Allow));

    // Prevent the current user from writing or changing the
    // permission set of the key. Note that if Delete permission
    // were not allowed in the previous access rule, denying
    // WriteKey permission would prevent the user from deleting the
    // key.
    regSecurity->AddAccessRule(gcnew RegistryAccessRule(user,
        RegistryRights::WriteKey | RegistryRights::ChangePermissions,
        InheritanceFlags::None,
        PropagationFlags::None,
        AccessControlType::Deny));

    // Create the example key with registry security.
    RegistryKey^ createdKey = nullptr;
    try
    {
        createdKey = Registry::CurrentUser->CreateSubKey(
            "RegistryRightsExample", RegistryKeyPermissionCheck::Default,
            regSecurity);
        Console::WriteLine("{0}Example key created.", Environment::NewLine);
        createdKey->SetValue("ValueName", "StringValue");
    }
    catch (SecurityException^ ex)
    {
        Console::WriteLine("{0}You do not have the permissions required " +
            "to create the example key:{0}{1}", Environment::NewLine, ex);
        return 0;
    }
    if (createdKey != nullptr)
    {
        createdKey->Close();
    }

    RegistryKey^ openedKey;

    // Open the key with read access.
    openedKey = Registry::CurrentUser->OpenSubKey("RegistryRightsExample",
        false);
    Console::WriteLine("{0}Retrieved value: {1}",
        Environment::NewLine, openedKey->GetValue("ValueName"));
    openedKey->Close();

    // Attempt to open the key with write access.
    try
    {
        openedKey = Registry::CurrentUser->OpenSubKey("RegistryRightsExample",
            true);
    }
    catch (SecurityException^ ex)
    {
        Console::WriteLine("{0}You do not have the permissions required " +
            "to write to the example key:{0}{1}", Environment::NewLine, ex);
    }
    if (openedKey != nullptr)
    {
        openedKey->Close();
    }

    // Attempt to change permissions for the key.
    try
    {
        regSecurity = gcnew RegistrySecurity();
        regSecurity->AddAccessRule(gcnew RegistryAccessRule(user,
            RegistryRights::WriteKey,
            InheritanceFlags::None,
            PropagationFlags::None,
            AccessControlType::Allow));
        openedKey = Registry::CurrentUser->OpenSubKey("RegistryRightsExample",
            false);
        openedKey->SetAccessControl(regSecurity);
        Console::WriteLine("{0}Example key permissions were changed.", 
            Environment::NewLine);
    }
    catch (UnauthorizedAccessException^ ex)
    {
        Console::WriteLine("{0}You are not authorized to change " +
            "permissions for the example key:{0}{1}", Environment::NewLine, ex);
    }
    if (openedKey != nullptr)
    {
        openedKey->Close();
    }

    Console::WriteLine("{0}Press Enter to delete the example key.", 
        Environment::NewLine);
    Console::ReadLine();

    try
    {
        Registry::CurrentUser->DeleteSubKey("RegistryRightsExample");
        Console::WriteLine("Example key was deleted.");
    }
    catch(SecurityException^ ex)
    {
        Console::WriteLine("{0}You do not have the permissions required to "
            + "delete the example key:{0}{1}", Environment::NewLine, ex);
    }
}

using System;
using System.Reflection;
using System.Security;
using System.Security.AccessControl;
using Microsoft.Win32;

public class Example
{
    public static void Main()
    {
        // Delete the example key if it exists.
        try
        {
            Registry.CurrentUser.DeleteSubKey("RegistryRightsExample");
            Console.WriteLine("Example key has been deleted.");
        }
        catch (ArgumentException)
        {
            // ArgumentException is thrown if the key does not exist. In
            // this case, there is no reason to display a message.
        }
        catch (Exception ex)
        {
            Console.WriteLine("Unable to delete the example key: {0}", ex);
            return;
        }

        string user = Environment.UserDomainName + "\\" + Environment.UserName;

        RegistrySecurity rs = new RegistrySecurity();

        // Allow the current user to read and delete the key.
        //
        rs.AddAccessRule(new RegistryAccessRule(user,
            RegistryRights.ReadKey | RegistryRights.Delete,
            InheritanceFlags.None,
            PropagationFlags.None,
            AccessControlType.Allow));

        // Prevent the current user from writing or changing the
        // permission set of the key. Note that if Delete permission
        // were not allowed in the previous access rule, denying
        // WriteKey permission would prevent the user from deleting the
        // key.
        rs.AddAccessRule(new RegistryAccessRule(user,
            RegistryRights.WriteKey | RegistryRights.ChangePermissions,
            InheritanceFlags.None,
            PropagationFlags.None,
            AccessControlType.Deny));

        // Create the example key with registry security.
        RegistryKey rk = null;
        try
        {
            rk = Registry.CurrentUser.CreateSubKey("RegistryRightsExample",
                RegistryKeyPermissionCheck.Default, rs);
            Console.WriteLine("\r\nExample key created.");
            rk.SetValue("ValueName", "StringValue");
        }
        catch (Exception ex)
        {
            Console.WriteLine("\r\nUnable to create the example key: {0}", ex);
        }
        if (rk != null) rk.Close();

        rk = Registry.CurrentUser;

        RegistryKey rk2;

        // Open the key with read access.
        rk2 = rk.OpenSubKey("RegistryRightsExample", false);
        Console.WriteLine("\r\nRetrieved value: {0}", rk2.GetValue("ValueName"));
        rk2.Close();

        // Attempt to open the key with write access.
        try
        {
            rk2 = rk.OpenSubKey("RegistryRightsExample", true);
        }
        catch (SecurityException ex)
        {
            Console.WriteLine("\nUnable to write to the example key." +
                " Caught SecurityException: {0}", ex.Message);
        }
        if (rk2 != null) rk2.Close();

        // Attempt to change permissions for the key.
        try
        {
            rs = new RegistrySecurity();
            rs.AddAccessRule(new RegistryAccessRule(user,
                RegistryRights.WriteKey,
                InheritanceFlags.None,
                PropagationFlags.None,
                AccessControlType.Allow));
            rk2 = rk.OpenSubKey("RegistryRightsExample", false);
            rk2.SetAccessControl(rs);
            Console.WriteLine("\r\nExample key permissions were changed.");
        }
        catch (UnauthorizedAccessException ex)
        {
            Console.WriteLine("\nUnable to change permissions for the example key." +
                " Caught UnauthorizedAccessException: {0}", ex.Message);
        }
        if (rk2 != null) rk2.Close();

        Console.WriteLine("\r\nPress Enter to delete the example key.");
        Console.ReadLine();

        try
        {
            rk.DeleteSubKey("RegistryRightsExample");
            Console.WriteLine("Example key was deleted.");
        }
        catch(Exception ex)
        {
            Console.WriteLine("Unable to delete the example key: {0}", ex);
        }

        rk.Close();
    }
}

/* This code example produces the following output:

Example key created.

Retrieved value: StringValue

Unable to write to the example key. Caught SecurityException: Requested registry access is not allowed.

Unable to change permissions for the example key. Caught UnauthorizedAccessException: Cannot write to the registry key.

Press Enter to delete the example key.

Example key was deleted.
 */

Imports System.Reflection
Imports System.Security
Imports System.Security.AccessControl
Imports Microsoft.Win32

Public Class Example
    Public Shared Sub Main()
        ' Delete the example key if it exists.
        Try
            Registry.CurrentUser.DeleteSubKey("RegistryRightsExample")
            Console.WriteLine("Example key has been deleted.")
        Catch ex As ArgumentException
            ' ArgumentException is thrown if the key does not exist. In
            ' this case, there is no reason to display a message.
        Catch ex As Exception
            Console.WriteLine("Unable to delete the example key: {0}", ex)
            Return
        End Try

        Dim user As String = Environment.UserDomainName & "\" & Environment.UserName

        Dim rs As New RegistrySecurity()

        ' Allow the current user to read and delete the key.
        '
        rs.AddAccessRule(new RegistryAccessRule(user, _
            RegistryRights.ReadKey Or RegistryRights.Delete, _
            InheritanceFlags.None, _
            PropagationFlags.None, _
            AccessControlType.Allow))

        ' Prevent the current user from writing or changing the
        ' permission set of the key. Note that if Delete permission
        ' were not allowed in the previous access rule, denying
        ' WriteKey permission would prevent the user from deleting the 
        ' key.
        rs.AddAccessRule(new RegistryAccessRule(user, _
            RegistryRights.WriteKey Or RegistryRights.ChangePermissions, _
            InheritanceFlags.None, _
            PropagationFlags.None, _
            AccessControlType.Deny))

        ' Create the example key with registry security.
        Dim rk As RegistryKey = Nothing
        Try
            rk = Registry.CurrentUser.CreateSubKey("RegistryRightsExample", _
                RegistryKeyPermissionCheck.Default, rs)
            Console.WriteLine(vbCrLf & "Example key created.")
            rk.SetValue("ValueName", "StringValue")
        Catch ex As Exception
            Console.WriteLine(vbCrLf & "Unable to create the example key: {0}", ex)
        End Try

        If rk IsNot Nothing Then rk.Close()

        rk = Registry.CurrentUser

        Dim rk2 As RegistryKey
        
        ' Open the key with read access.
        rk2 = rk.OpenSubKey("RegistryRightsExample", False)
        Console.WriteLine(vbCrLf & "Retrieved value: {0}", rk2.GetValue("ValueName"))
        rk2.Close()

        ' Attempt to open the key with write access.
        Try
            rk2 = rk.OpenSubKey("RegistryRightsExample", True)
        Catch ex As SecurityException
            Console.WriteLine(vbCrLf & "Unable to write to the example key." _
                & " Caught SecurityException: {0}", ex.Message)
        End Try
        If rk2 IsNot Nothing Then rk2.Close()

        ' Attempt to change permissions for the key.
        Try
            rs = New RegistrySecurity()
            rs.AddAccessRule(new RegistryAccessRule(user, _
                RegistryRights.WriteKey, _
                InheritanceFlags.None, _
                PropagationFlags.None, _
                AccessControlType.Allow))
            rk2 = rk.OpenSubKey("RegistryRightsExample", False)
            rk2.SetAccessControl(rs)
            Console.WriteLine(vbCrLf & "Example key permissions were changed.")
        Catch ex As UnauthorizedAccessException
            Console.WriteLine(vbCrLf & "Unable to change permissions for the example key." _
                & " Caught UnauthorizedAccessException: {0}", ex.Message)
        End Try
        If rk2 IsNot Nothing Then rk2.Close()

        Console.WriteLine(vbCrLf & "Press Enter to delete the example key.")
        Console.ReadLine()

        Try
            rk.DeleteSubKey("RegistryRightsExample")
            Console.WriteLine("Example key was deleted.")
        Catch ex As Exception
            Console.WriteLine("Unable to delete the example key: {0}", ex)
        End Try

        rk.Close()
    End Sub
End Class

' This code produces the following output:
'
'Example key created.
'
'Retrieved value: StringValue
'
'Unable to write to the example key. Caught SecurityException: Requested registry access is not allowed.
'
'Unable to change permissions for the example key. Caught UnauthorizedAccessException: Cannot write to the registry key.
'
'Press Enter to delete the example key.
'
'Example key was deleted.

Remarks

To modify permissions for a registry key, use the GetAccessControl method to obtain a RegistrySecurity object representing the existing Windows access control security, modify that RegistrySecurity object, and then use the SetAccessControl method to update security for the key.

Caution

The RegistrySecurity object specified for registrySecurity replaces the existing security for the registry key. To add permissions for a new user, use the GetAccessControl method to obtain the existing access control security, and then modify it.