#371 Conditionally register auth scheme base on ANCM variable

src/Microsoft.AspNetCore.Server.IISIntegration/IISDefaults.cs

@@ -5,6 +5,7 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
 {
     public class IISDefaults
     {
+        public static readonly string AuthenticationScheme = "Windows";
         public const string Negotiate = "Negotiate";
         public const string Ntlm = "NTLM";
     }

src/Microsoft.AspNetCore.Server.IISIntegration/IISMiddleware.cs

@@ -18,8 +18,6 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
 {
     public class IISMiddleware
     {
-        public static readonly string AuthenticationScheme = "Windows";
-
         private const string MSAspNetCoreClientCert = "MS-ASPNETCORE-CLIENTCERT";
         private const string MSAspNetCoreToken = "MS-ASPNETCORE-TOKEN";
 
@@ -50,10 +48,9 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
             _next = next;
             _options = options.Value;
 
-
             if (_options.ForwardWindowsAuthentication)
             {
-                authentication.AddScheme(new AuthenticationScheme(AuthenticationScheme, displayName: null, handlerType: typeof(AuthenticationHandler)));
+                authentication.AddScheme(new AuthenticationScheme(IISDefaults.AuthenticationScheme, displayName: null, handlerType: typeof(AuthenticationHandler)));
             }
 
             _pairingToken = pairingToken;
@@ -94,7 +91,7 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
 
             if (_options.ForwardWindowsAuthentication)
             {
-                var result = await httpContext.AuthenticateAsync(AuthenticationScheme);
+                var result = await httpContext.AuthenticateAsync(IISDefaults.AuthenticationScheme);
                 if (result.Succeeded)
                 {
                     httpContext.User = result.Principal;

src/Microsoft.AspNetCore.Server.IISIntegration/IISOptions.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 namespace Microsoft.AspNetCore.Builder
@@ -6,10 +6,10 @@ namespace Microsoft.AspNetCore.Builder
     public class IISOptions
     {
         /// <summary>
-        /// If true authentication middleware will try to authenticate using platform handler windows authentication
+        /// If true authentication middleware will try to authenticate using AspNetCoreModule windows authentication
-        /// If false authentication middleware won't be added
+        /// If false authentication components won't be added
         /// </summary>
-        public bool ForwardWindowsAuthentication { get; set; } = true;
+        internal bool ForwardWindowsAuthentication { get; set; } = true;
 
         /// <summary>
         /// Populates the ITLSConnectionFeature if the MS-ASPNETCORE-CLIENTCERT request header is present.

src/Microsoft.AspNetCore.Server.IISIntegration/WebHostBuilderIISExtensions.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Linq;
 using Microsoft.AspNetCore.Authentication;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
@@ -17,6 +18,7 @@ namespace Microsoft.AspNetCore.Hosting
         private static readonly string ServerPort = "PORT";
         private static readonly string ServerPath = "APPL_PATH";
         private static readonly string PairingToken = "TOKEN";
+        private static readonly string IISAuth = "IIS_HTTPAUTH";
 
         /// <summary>
         /// Configures the port and base path the server should listen on when running behind AspNetCoreModule.
@@ -40,12 +42,32 @@ namespace Microsoft.AspNetCore.Hosting
             var port = hostBuilder.GetSetting(ServerPort) ?? Environment.GetEnvironmentVariable($"ASPNETCORE_{ServerPort}");
             var path = hostBuilder.GetSetting(ServerPath) ?? Environment.GetEnvironmentVariable($"ASPNETCORE_{ServerPath}");
             var pairingToken = hostBuilder.GetSetting(PairingToken) ?? Environment.GetEnvironmentVariable($"ASPNETCORE_{PairingToken}");
+            var iisAuth = hostBuilder.GetSetting(IISAuth) ?? Environment.GetEnvironmentVariable($"ASPNETCORE_{IISAuth}");
 
             if (!string.IsNullOrEmpty(port) && !string.IsNullOrEmpty(path) && !string.IsNullOrEmpty(pairingToken))
             {
                 // Set flag to prevent double service configuration
                 hostBuilder.UseSetting(nameof(UseIISIntegration), true.ToString());
 
+                var enableAuth = false;
+                if (string.IsNullOrEmpty(iisAuth))
+                {
+                    // back compat with older ANCM versions
+                    enableAuth = true;
+                }
+                else
+                {
+                    // Lightup a new ANCM variable that tells us if auth is enabled.
+                    foreach (var authType in iisAuth.Split(';'))
+                    {
+                        if (!string.Equals(authType, "anonymous", StringComparison.OrdinalIgnoreCase))
+                        {
+                            enableAuth = true;
+                            break;
+                        }
+                    }
+                }
+
                 var address = "http://localhost:" + port;
                 hostBuilder.CaptureStartupErrors(true);
 
@@ -59,6 +81,10 @@ namespace Microsoft.AspNetCore.Hosting
                     {
                         options.ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto;
                     });
+                    services.Configure<IISOptions>(options =>
+                    {
+                        options.ForwardWindowsAuthentication = enableAuth;
+                    });
                     services.AddAuthenticationCore();
                 });
             }

test/IISIntegration.FunctionalTests/HelloWorldTest.cs

@@ -85,6 +85,10 @@ namespace Microsoft.AspNetCore.Server.IISIntegration.FunctionalTests
                         response = await deploymentResult.HttpClient.GetAsync("/BodyLimit");
                         responseText = await response.Content.ReadAsStringAsync();
                         Assert.Equal("null", responseText);
+
+                        response = await deploymentResult.HttpClient.GetAsync("/Auth");
+                        responseText = await response.Content.ReadAsStringAsync();
+                        Assert.True("backcompat;Windows".Equals(responseText) || "latest;null".Equals(responseText), "Auth");
                     }
                     catch (XunitException)
                     {

test/Microsoft.AspNetCore.Server.IISIntegration.Tests/IISMiddlewareTests.cs

@@ -156,7 +156,7 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
                     app.Run(async context => 
                     {
                         var auth = context.RequestServices.GetRequiredService<IAuthenticationSchemeProvider>();
-                        var windows = await auth.GetSchemeAsync(IISMiddleware.AuthenticationScheme);
+                        var windows = await auth.GetSchemeAsync(IISDefaults.AuthenticationScheme);
                         Assert.NotNull(windows);
                         Assert.Null(windows.DisplayName);
                         Assert.Equal("Microsoft.AspNetCore.Server.IISIntegration.AuthenticationHandler", windows.HandlerType.FullName);
@@ -197,7 +197,7 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
                     {
                         var auth = context.RequestServices.GetService<IAuthenticationSchemeProvider>();
                         Assert.NotNull(auth);
-                        var windowsAuth = await auth.GetSchemeAsync(IISMiddleware.AuthenticationScheme);
+                        var windowsAuth = await auth.GetSchemeAsync(IISDefaults.AuthenticationScheme);
                         if (forward)
                         {
                             Assert.NotNull(windowsAuth);

test/TestSites/StartupHelloWorld.cs

@@ -1,9 +1,13 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
+using System.Linq;
+using Microsoft.AspNetCore.Authentication;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 
 namespace TestSites
@@ -12,23 +16,42 @@ namespace TestSites
     {
         public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
         {
-            app.Run(ctx =>
+            app.Run(async ctx =>
             {
                 if (ctx.Request.Path.Value.StartsWith("/Path"))
                 {
-                    return ctx.Response.WriteAsync(ctx.Request.Path.Value);
+                    await ctx.Response.WriteAsync(ctx.Request.Path.Value);
+                    return;
                 }
                 if (ctx.Request.Path.Value.StartsWith("/Query"))
                 {
-                    return ctx.Response.WriteAsync(ctx.Request.QueryString.Value);
+                    await ctx.Response.WriteAsync(ctx.Request.QueryString.Value);
+                    return;
                 }
                 if (ctx.Request.Path.Value.StartsWith("/BodyLimit"))
                 {
-                    return ctx.Response.WriteAsync(
+                    await ctx.Response.WriteAsync(
                         ctx.Features.Get<IHttpMaxRequestBodySizeFeature>()?.MaxRequestBodySize?.ToString() ?? "null");
+                    return;
                 }
 
-                return ctx.Response.WriteAsync("Hello World");
+                if (ctx.Request.Path.StartsWithSegments("/Auth"))
+                {
+                    var iisAuth = Environment.GetEnvironmentVariable("ASPNETCORE_IIS_HTTPAUTH");
+                    var authProvider = ctx.RequestServices.GetService<IAuthenticationSchemeProvider>();
+                    var authScheme = (await authProvider.GetAllSchemesAsync()).SingleOrDefault();
+                    if (string.IsNullOrEmpty(iisAuth))
+                    {
+                        await ctx.Response.WriteAsync("backcompat;" + authScheme?.Name ?? "null");
+                    }
+                    else
+                    {
+                        await ctx.Response.WriteAsync("latest;" + authScheme?.Name ?? "null");
+                    }
+                    return;
+                }
+
+                await ctx.Response.WriteAsync("Hello World");
             });
         }
     }

test/TestSites/StartupNtlmAuthentication.cs

@@ -74,7 +74,7 @@ namespace TestSites
                     }
                     else
                     {
-                        return context.ChallengeAsync(IISMiddleware.AuthenticationScheme);
+                        return context.ChallengeAsync(IISDefaults.AuthenticationScheme);
                     }
                 }