Azure B2C authentication does not work with WebForms

Question

I have an Asp.Net 4.7 WebForms legacy application written in vb.net. I need to add Azure B2C authentication. So I registred an app with Azure, and added OWIN middleware NuGet packages, and made all necessary configuration changes. I expect to see the log in screen when the application runs, and yet it does not happen. The application just runs without any authentication.
To narrow down the problem, I created a completely new WebForms application with Asp.Net 4.7 and vb.net. But the result was the same.

Here is the code:

Startup.vb

Imports System.Threading.Tasks  
Imports Microsoft.IdentityModel.Protocols.OpenIdConnect  
Imports Microsoft.IdentityModel.Tokens  
Imports Microsoft.Owin.Security  
Imports Microsoft.Owin.Security.Cookies  
Imports Microsoft.Owin.Security.Notifications  
Imports Microsoft.Owin.Security.OpenIdConnect  
Imports Owin  
  
Public Class Startup  
    Private Shared clientId As String = ConfigurationManager.AppSettings("ida:ClientId")  
    Private Shared aadInstance As String = ConfigurationManager.AppSettings("ida:AadInstance")  
    Private Shared tenant As String = ConfigurationManager.AppSettings("ida:Tenant")  
    Private Shared redirectUri As String = ConfigurationManager.AppSettings("ida:RedirectUri")  
    'Public Shared SignUpPolicyId As String = ConfigurationManager.AppSettings("ida:SignUpPolicyId")  
    'Public Shared ProfilePolicyId As String = ConfigurationManager.AppSettings("ida:UserProfilePolicyId")  
    Public Shared SignInPolicyId As String = ConfigurationManager.AppSettings("ida:SignInPolicyId")  
  
    Public Sub Configuration(ByVal app As IAppBuilder)  
        app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType)  
        app.UseCookieAuthentication(New CookieAuthenticationOptions())  
        'app.UseOpenIdConnectAuthentication(CreateOptionsFromPolicy(SignUpPolicyId))  
        'app.UseOpenIdConnectAuthentication(CreateOptionsFromPolicy(ProfilePolicyId))  
        app.UseOpenIdConnectAuthentication(CreateOptionsFromPolicy(SignInPolicyId))  
        'app.UseStageMarker(PipelineStage.Authenticate)  
    End Sub  
  
    Private Function AuthenticationFailed(ByVal notification As AuthenticationFailedNotification(Of OpenIdConnectMessage, OpenIdConnectAuthenticationOptions)) As Task  
        notification.HandleResponse()  
  
        If notification.Exception.Message = "access_denied" Then  
            notification.Response.Redirect("/")  
        Else  
            notification.Response.Redirect("/Home/Error?message=" & notification.Exception.Message)  
        End If  
  
        Return Task.FromResult(0)  
    End Function  
  
    Private Function CreateOptionsFromPolicy(ByVal policy As String) As OpenIdConnectAuthenticationOptions  
        Dim options = New OpenIdConnectAuthenticationOptions With {  
            .MetadataAddress = String.Format(aadInstance, tenant, policy),  
            .AuthenticationType = policy,  
            .ClientId = clientId,  
            .RedirectUri = redirectUri,  
            .PostLogoutRedirectUri = redirectUri,  
            .Notifications = New OpenIdConnectAuthenticationNotifications With {  
                .AuthenticationFailed = AddressOf AuthenticationFailed  
            },  
            .Scope = "openid",  
            .ResponseType = "id_token",  
            .TokenValidationParameters = New TokenValidationParameters With {  
                .NameClaimType = "name"  
            }  
        }  
        Return options  
    End Function  
End Class

Web.config

The execution comes to the Configuration() method, and yet it doesn't help. What am I missing?

Answer

Hello @Dmitriy Reznik , your web.config (don't pay attention to appSettings) should look similar to this:

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Azure B2C authentication does not work with WebForms

1 answer