RegistrySecurity.AddAccessRule(RegistryAccessRule) Method
Definition
Important
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Searches for a matching access control with which the new rule can be merged. If none are found, adds the new rule.
public:
void AddAccessRule(System::Security::AccessControl::RegistryAccessRule ^ rule);public void AddAccessRule (System.Security.AccessControl.RegistryAccessRule rule);override this.AddAccessRule : System.Security.AccessControl.RegistryAccessRule -> unitPublic Sub AddAccessRule (rule As RegistryAccessRule)Parameters
- rule
- RegistryAccessRule
The access control rule to add.
Exceptions
rule is null.
Examples
The following code example creates registry access rules and adds them to a RegistrySecurity object, showing how rules that allow and deny rights remain separate, while compatible rules of the same kind are merged.
Note
This example does not attach the security object to a RegistryKey object. Examples that attach security objects can be found in RegistryKey.GetAccessControl and RegistryKey.SetAccessControl.
A code example that demonstrates inheritance and propagation flags can be found in the RegistryAccessRule class.
using System;
using Microsoft.Win32;
using System.Security.AccessControl;
using System.Security.Principal;
public class Example
{
public static void Main()
{
// Create a string representing the current user.
string user = Environment.UserDomainName + "\\"
+ Environment.UserName;
// Create a security object that grants no access.
RegistrySecurity mSec = new RegistrySecurity();
// Add a rule that grants the current user the
// right to read the key.
RegistryAccessRule rule = new RegistryAccessRule(user,
RegistryRights.ReadKey,
AccessControlType.Allow);
mSec.AddAccessRule(rule);
// Add a rule that denies the current user the
// right to change permissions on the Registry.
rule = new RegistryAccessRule(user,
RegistryRights.ChangePermissions,
AccessControlType.Deny);
mSec.AddAccessRule(rule);
// Display the rules in the security object.
ShowSecurity(mSec);
// Add a rule that allows the current user the
// right to read permissions on the Registry. This
// rule is merged with the existing Allow rule.
rule = new RegistryAccessRule(user,
RegistryRights.WriteKey,
AccessControlType.Allow);
mSec.AddAccessRule(rule);
ShowSecurity(mSec);
}
private static void ShowSecurity(RegistrySecurity security)
{
Console.WriteLine("\r\nCurrent access rules:\r\n");
foreach( RegistryAccessRule ar in
security.GetAccessRules(true, true, typeof(NTAccount)) )
{
Console.WriteLine(" User: {0}", ar.IdentityReference);
Console.WriteLine(" Type: {0}", ar.AccessControlType);
Console.WriteLine(" Rights: {0}", ar.RegistryRights);
Console.WriteLine();
}
}
}
/* This code example produces output similar to following:
Current access rules:
User: TestDomain\TestUser
Type: Deny
Rights: ChangePermissions
User: TestDomain\TestUser
Type: Allow
Rights: ReadKey
Current access rules:
User: TestDomain\TestUser
Type: Deny
Rights: ChangePermissions
User: TestDomain\TestUser
Type: Allow
Rights: SetValue, CreateSubKey, ReadKey
*/
Imports Microsoft.Win32
Imports System.Security.AccessControl
Imports System.Security.Principal
Public Class Example
Public Shared Sub Main()
' Create a string representing the current user.
Dim user As String = Environment.UserDomainName _
& "\" & Environment.UserName
' Create a security object that grants no access.
Dim mSec As New RegistrySecurity()
' Add a rule that grants the current user the
' right to read the key.
Dim rule As New RegistryAccessRule(user, _
RegistryRights.ReadKey, _
AccessControlType.Allow)
mSec.AddAccessRule(rule)
' Add a rule that denies the current user the
' right to change permissions on the Registry.
rule = New RegistryAccessRule(user, _
RegistryRights.ChangePermissions, _
AccessControlType.Deny)
mSec.AddAccessRule(rule)
' Display the rules in the security object.
ShowSecurity(mSec)
' Add a rule that allows the current user the
' right to read permissions on the Registry. This
' rule is merged with the existing Allow rule.
rule = New RegistryAccessRule(user, _
RegistryRights.WriteKey, _
AccessControlType.Allow)
mSec.AddAccessRule(rule)
ShowSecurity(mSec)
End Sub
Private Shared Sub ShowSecurity(ByVal security As RegistrySecurity)
Console.WriteLine(vbCrLf & "Current access rules:" & vbCrLf)
For Each ar As RegistryAccessRule In _
security.GetAccessRules(True, True, GetType(NTAccount))
Console.WriteLine(" User: {0}", ar.IdentityReference)
Console.WriteLine(" Type: {0}", ar.AccessControlType)
Console.WriteLine(" Rights: {0}", ar.RegistryRights)
Console.WriteLine()
Next
End Sub
End Class
'This code example produces output similar to following:
'
'Current access rules:
'
' User: TestDomain\TestUser
' Type: Deny
' Rights: ChangePermissions
'
' User: TestDomain\TestUser
' Type: Allow
' Rights: ReadKey
'
'
'Current access rules:
'
' User: TestDomain\TestUser
' Type: Deny
' Rights: ChangePermissions
'
' User: TestDomain\TestUser
' Type: Allow
' Rights: SetValue, CreateSubKey, ReadKey
Remarks
The AddAccessRule method searches for rules with the same user or group and the same AccessControlType as rule. If none are found, rule is added. If a matching rule is found, the rights in rule are merged with the existing rule.
Rules cannot be merged if they have different inheritance flags. For example, if a user is allowed read access with no inheritance flags, and AddAccessRule is used to add a rule giving the user write access with inheritance for subkeys (InheritanceFlags.ContainerInherit), the two rules cannot be merged.
Rules with different AccessControlType values are never merged.
Rules express rights in the most economical way. For example, if a user has QueryValues, Notify and ReadPermissions rights, and you add a rule allowing EnumerateSubKeys rights, the user has all the constituent parts of ReadKey rights. If you query the user's rights, you will see a rule containing ReadKey rights. Similarly, if you remove EnumerateSubKeys rights, the other constituents of ReadKey rights will reappear.
