PrincipalPermissionMode Enumeration
Sets the mode for authorization checks when using the PrincipalPermissionAttribute to control access to a method.
Assembly: System.ServiceModel (in System.ServiceModel.dll)
| Member name | Description | |
|---|---|---|
| Always | Always enables the user to specify a IPrincipal class for CurrentPrincipal. | |
| Custom | Enables the user to specify a custom IPrincipal class for CurrentPrincipal. | |
| None | CurrentPrincipal is not set. | |
| UseAspNetRoles | CurrentPrincipal is set based on the ASP.NET role provider (RoleProvider). | |
| UseWindowsGroups | CurrentPrincipal is set based on Windows (WindowsPrincipal). If the user identity is not associated with a Windows account, anonymous Windows is used. |
When applying the PrincipalPermissionAttribute to a method, this mode specifies which set of roles to use when authorizing access. By default, the attribute uses Windows groups (such as Administrator or Users) to specify the role to which the user must belong.
To set the mode programmatically, create an instance of the ServiceHost class, then find the ServiceAuthorizationBehavior in its collection of behaviors, and set the PrincipalPermissionMode to the appropriate enumeration. The following example sets the property to UseAspNetRoles.
Dim myServiceHost As New ServiceHost(GetType(Calculator), baseUri) Dim myServiceBehavior As ServiceAuthorizationBehavior = myServiceHost.Description.Behaviors.Find(Of ServiceAuthorizationBehavior)() myServiceBehavior.PrincipalPermissionMode = PrincipalPermissionMode.UseAspNetRoles
You can also set the behavior in configuration by adding a <serviceAuthorization> element to the <serviceBehaviors> of a configuration file, as shown in the following code.
' Only a client authenticated with a valid certificate that has the ' specified subject name and thumbprint can call this method. <PrincipalPermission(SecurityAction.Demand, Name := "CN=ReplaceWithSubjectName; 123456712345677E8E230FDE624F841B1CE9D41E")> _ Public Function Multiply(ByVal a As Double, ByVal b As Double) As Double Return a * b End Function
The enumeration affects how the PrincipalPermissionAttribute attribute authorizes a user when it is applied to a method. The following example applies the attribute to a method and demands that the user belong to the Users group on the computer. This code works only when the PrincipalPermissionMode is set to UseWindowsGroup (the default setting).
The UseAspNetRoles value is used for all credential types. This mode enables Windows Communication Foundation (WCF) to use the ASP.NET role provider to make authorization decisions.
When the credential for a service is an X.509 certificate, you can set the Name property of the PrincipalPermissionAttribute to a string that consists of the concatenated values of the Subject field and the Thumbprint field, as shown in the following example.
Dim myServiceHost As New ServiceHost(GetType(Calculator), baseUri) Dim myServiceBehavior As ServiceAuthorizationBehavior = myServiceHost.Description.Behaviors.Find(Of ServiceAuthorizationBehavior)() myServiceBehavior.PrincipalPermissionMode = PrincipalPermissionMode.UseAspNetRoles Dim sm As New MyServiceAuthorizationManager() myServiceBehavior.ServiceAuthorizationManager = sm
The concatenated string consists of the subject and thumbprint values separated by a semicolon and a space.
It is also possible for a certificate to have a Subject field set to a null string. In that case, you can set the Name property to a semicolon followed by a space and then the thumbprint, as shown in the following example.
' Only a client authenticated with a valid certificate that has the ' specified thumbprint can call this method. <PrincipalPermission(SecurityAction.Demand, Name := "; 123456712345677E8E230FDE624F841B1CE9D41E")> _ Public Function Divide(ByVal a As Double, ByVal b As Double) As Double Return a * b End Function
If an ASP.NET role provider is present, you can also set the Role property to a role in the database. By default, the database is represented by the SqlRoleProvider. You can also set a custom role provider with the RoleProvider property of the ServiceAuthorizationBehavior class. The following code sets the role to Administrators. Note that the role provider must map the user account to that role.
<PrincipalPermission(SecurityAction.Demand, Role := "Administrators")> _ Public Function ReadFile(ByVal fileName As String) As String ' Code not shown. Return "Not implemented" End Function
For more information about the ASP.NET Role provider, see How To: Use Role Manager in ASP.NET 2.0.
For more information about using WCF and the role provider, see How to: Use the ASP.NET Role Provider with a Service.
When the property is set to Custom, you must also provide a custom class that implements the IAuthorizationPolicy class. This class is responsible for providing the caller's IPrincipal representation inside the Properties collection. It must store the IPrincipal instance to the properties collection using the "Principal" string key, as shown in the following example.
evaluationContext.Properties["Principal"]=new CustomPrincipal(identity);
The role-based security in .NET Framework enables applications to specify authorizations through code. By specifying the PrincipalPermission demand, the CurrentPrincipal must satisfy the PrincipalPermission requirement. For example, that the user must be in a specific role or group. Otherwise, the thread is not authorized to execute the code, which results in an exception. WCF provides a set of PrincipalPermissionMode selections to specify the CurrentPrincipal based on SecurityContext accordingly.
The following example shows how to specify UseAspNetRoles.
Namespace TestPrincipalPermission Friend Class PrincipalPermissionModeWindows <ServiceContract> _ Private Interface ISecureService <OperationContract> _ Function Method1() As String End Interface Private Class SecureService Implements ISecureService <PrincipalPermission(SecurityAction.Demand, Role:="everyone")> _ Public Function Method1() As String Implements ISecureService.Method1 Return String.Format("Hello, ""{0}""", Thread.CurrentPrincipal.Identity.Name) End Function End Class Public Sub Run() Dim serviceUri As New Uri("http://localhost:8006/Service") Dim service As New ServiceHost(GetType(SecureService)) service.AddServiceEndpoint(GetType(ISecureService), GetBinding(), serviceUri) service.Authorization.PrincipalPermissionMode = PrincipalPermissionMode.UseAspNetRoles service.Open() Dim sr As New EndpointAddress(serviceUri, EndpointIdentity.CreateUpnIdentity(WindowsIdentity.GetCurrent().Name)) Dim cf As New ChannelFactory(Of ISecureService)(GetBinding(), sr) Dim client As ISecureService = cf.CreateChannel() Console.WriteLine("Client received response from Method1: {0}", client.Method1()) CType(client, IChannel).Close() Console.ReadLine() service.Close() End Sub Public Shared Function GetBinding() As Binding Dim binding As New WSHttpBinding(SecurityMode.Message) binding.Security.Message.ClientCredentialType = MessageCredentialType.Windows Return binding End Function End Class End Namespace
The following example shows how to specify Custom.
Namespace CustomMode Public Class Test Public Shared Sub Main() Try Dim ppwm As New ShowPrincipalPermissionModeCustom() ppwm.Run() Catch exc As Exception Console.WriteLine("Error: {0}", exc.Message) Console.ReadLine() End Try End Sub End Class Friend Class ShowPrincipalPermissionModeCustom <ServiceContract> _ Private Interface ISecureService <OperationContract> _ Function Method1(ByVal request As String) As String End Interface <ServiceBehavior> _ Private Class SecureService Implements ISecureService <PrincipalPermission(SecurityAction.Demand, Role:="everyone")> _ Public Function Method1(ByVal request As String) As String Implements ISecureService.Method1 Return String.Format("Hello, ""{0}""", Thread.CurrentPrincipal.Identity.Name) End Function End Class Public Sub Run() Dim serviceUri As New Uri("http://localhost:8006/Service") Dim service As New ServiceHost(GetType(SecureService)) service.AddServiceEndpoint(GetType(ISecureService), GetBinding(), serviceUri) Dim policies As New List(Of IAuthorizationPolicy)() policies.Add(New CustomAuthorizationPolicy()) service.Authorization.ExternalAuthorizationPolicies = policies.AsReadOnly() service.Authorization.PrincipalPermissionMode = PrincipalPermissionMode.Custom service.Open() Dim sr As New EndpointAddress(serviceUri, EndpointIdentity.CreateUpnIdentity(WindowsIdentity.GetCurrent().Name)) Dim cf As New ChannelFactory(Of ISecureService)(GetBinding(), sr) Dim client As ISecureService = cf.CreateChannel() Console.WriteLine("Client received response from Method1: {0}", client.Method1("hello")) CType(client, IChannel).Close() Console.ReadLine() service.Close() End Sub Public Shared Function GetBinding() As Binding Dim binding As New WSHttpBinding(SecurityMode.Message) binding.Security.Message.ClientCredentialType = MessageCredentialType.Windows Return binding End Function Private Class CustomAuthorizationPolicy Implements IAuthorizationPolicy Private id_Renamed As String = Guid.NewGuid().ToString() Public ReadOnly Property Id() As String Implements System.IdentityModel.Policy.IAuthorizationComponent.Id Get Return Me.id_Renamed End Get End Property Public ReadOnly Property Issuer() As ClaimSet Implements IAuthorizationPolicy.Issuer Get Return ClaimSet.System End Get End Property Public Function Evaluate(ByVal context As EvaluationContext, ByRef state As Object) As Boolean Implements IAuthorizationPolicy.Evaluate Dim obj As Object = Nothing If (Not context.Properties.TryGetValue("Identities", obj)) Then Return False End If Dim identities As IList(Of IIdentity) = TryCast(obj, IList(Of IIdentity)) If obj Is Nothing OrElse identities.Count <= 0 Then Return False End If context.Properties("Principal") = New CustomPrincipal(identities(0)) Return True End Function End Class Private Class CustomPrincipal Implements IPrincipal Private identity_Renamed As IIdentity Public Sub New(ByVal identity As IIdentity) Me.identity_Renamed = identity End Sub Public ReadOnly Property Identity() As IIdentity Implements IPrincipal.Identity Get Return Me.identity_Renamed End Get End Property Public Function IsInRole(ByVal role As String) As Boolean Implements IPrincipal.IsInRole Return True End Function End Class End Class End Namespace
Available since 3.0