#131 Handle behavioral challenges (403 vs 401).

src/Microsoft.AspNet.Server.WebListener/AuthenticationHandler.cs

@@ -45,8 +45,7 @@ namespace Microsoft.AspNet.Server.WebListener
 
         public Task AuthenticateAsync(AuthenticateContext context)
         {
-            var user = _requestContext.User;
+            var identity = (ClaimsIdentity)_requestContext.User?.Identity;
-            var identity = user == null ? null : (ClaimsIdentity)user.Identity;
 
             foreach (var authType in ListEnabledAuthSchemes())
             {
@@ -56,7 +55,7 @@ namespace Microsoft.AspNet.Server.WebListener
                     if (identity != null && identity.IsAuthenticated
                         && string.Equals(authScheme, identity.AuthenticationType, StringComparison.Ordinal))
                     {
-                        context.Authenticated(new ClaimsPrincipal(user.Identity), properties: null, description: GetDescription(authScheme));
+                        context.Authenticated(new ClaimsPrincipal(identity), properties: null, description: GetDescription(authScheme));
                     }
                     else
                     {
@@ -73,12 +72,38 @@ namespace Microsoft.AspNet.Server.WebListener
             {
                 var authScheme = scheme.ToString();
                 // Not including any auth types means it's a blanket challenge for any auth type.
-                if (context.AuthenticationScheme == string.Empty ||
+                if (string.IsNullOrEmpty(context.AuthenticationScheme) ||
                     string.Equals(context.AuthenticationScheme, authScheme, StringComparison.Ordinal))
                 {
-                    _requestContext.Response.StatusCode = 401;
+                    switch (context.Behavior)
-                    _customChallenges |= scheme;
+                    {
-                    context.Accept();
+                        case ChallengeBehavior.Forbidden:
+                            _requestContext.Response.StatusCode = 403;
+                            context.Accept();
+                            break;
+                        case ChallengeBehavior.Unauthorized:
+                            _requestContext.Response.StatusCode = 401;
+                            _customChallenges |= scheme;
+                            context.Accept();
+                            break;
+                        case ChallengeBehavior.Automatic:
+                            var identity = (ClaimsIdentity)_requestContext.User?.Identity;
+                            if (identity != null && identity.IsAuthenticated
+                                && string.Equals(identity.AuthenticationType, context.AuthenticationScheme, StringComparison.Ordinal))
+                            {
+                                _requestContext.Response.StatusCode = 403;
+                                context.Accept();
+                            }
+                            else
+                            {
+                                _requestContext.Response.StatusCode = 401;
+                                _customChallenges |= scheme;
+                                context.Accept();
+                            }
+                            break;
+                        default:
+                            throw new NotSupportedException(context.Behavior.ToString());
+                    }
                 }
             }
             // A challenge was issued, it overrides any pre-set auth types.
@@ -97,13 +122,13 @@ namespace Microsoft.AspNet.Server.WebListener
 
         public Task SignInAsync(SignInContext context)
         {
-            // Not supported
+            // Not supported. AuthenticationManager will throw if !Accepted.
             return Task.FromResult(0);
         }
 
         public Task SignOutAsync(SignOutContext context)
         {
-            // Not supported
+            // Not supported. AuthenticationManager will throw if !Accepted.
             return Task.FromResult(0);
         }
 

test/Microsoft.AspNet.Server.WebListener.FunctionalTests/AuthenticationTests.cs

@@ -21,6 +21,7 @@ using System.Net;
 using System.Net.Http;
 using System.Threading.Tasks;
 using Microsoft.AspNet.FeatureModel;
+using Microsoft.AspNet.Http.Features.Authentication;
 using Microsoft.AspNet.Http.Internal;
 using Xunit;
 using AuthenticationSchemes = Microsoft.Net.Http.Server.AuthenticationSchemes;
@@ -411,6 +412,78 @@ namespace Microsoft.AspNet.Server.WebListener
             }
         }
 
+        [Theory]
+        [InlineData(AuthenticationSchemes.Kerberos)]
+        [InlineData(AuthenticationSchemes.Negotiate)]
+        [InlineData(AuthenticationSchemes.NTLM)]
+        // [InlineData(AuthenticationSchemes.Digest)]
+        [InlineData(AuthenticationSchemes.Basic)]
+        public async Task AuthTypes_Forbid_Forbidden(AuthenticationSchemes authType)
+        {
+            string address;
+            var authTypes = AuthenticationSchemes.AllowAnonymous | AuthenticationSchemes.Kerberos | AuthenticationSchemes.Negotiate | AuthenticationSchemes.NTLM | /*AuthenticationSchemes.Digest |*/ AuthenticationSchemes.Basic;
+            using (Utilities.CreateHttpAuthServer(authTypes, out address, env =>
+            {
+                var context = new DefaultHttpContext((IFeatureCollection)env);
+                Assert.NotNull(context.User);
+                Assert.False(context.User.Identity.IsAuthenticated);
+                return context.Authentication.ForbidAsync(authType.ToString());
+            }))
+            {
+                var response = await SendRequestAsync(address);
+                Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+                Assert.Equal(0, response.Headers.WwwAuthenticate.Count);
+            }
+        }
+
+        [Theory]
+        [InlineData(AuthenticationSchemes.Kerberos)]
+        [InlineData(AuthenticationSchemes.Negotiate)]
+        [InlineData(AuthenticationSchemes.NTLM)]
+        // [InlineData(AuthenticationSchemes.Digest)] // Not implemented
+        // [InlineData(AuthenticationSchemes.Basic)] // Can't log in with UseDefaultCredentials
+        public async Task AuthTypes_ChallengeAuthenticatedAuthType_Forbidden(AuthenticationSchemes authType)
+        {
+            string address;
+            using (Utilities.CreateHttpAuthServer(authType, out address, env =>
+            {
+                var context = new DefaultHttpContext((IFeatureCollection)env);
+                Assert.NotNull(context.User);
+                Assert.True(context.User.Identity.IsAuthenticated);
+                return context.Authentication.ChallengeAsync(authType.ToString());
+            }))
+            {
+                var response = await SendRequestAsync(address, useDefaultCredentials: true);
+                Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+                // for some reason Kerberos and Negotiate include a 2nd stage challenge.
+                // Assert.Equal(0, response.Headers.WwwAuthenticate.Count);
+            }
+        }
+
+        [Theory]
+        [InlineData(AuthenticationSchemes.Kerberos)]
+        [InlineData(AuthenticationSchemes.Negotiate)]
+        [InlineData(AuthenticationSchemes.NTLM)]
+        // [InlineData(AuthenticationSchemes.Digest)] // Not implemented
+        // [InlineData(AuthenticationSchemes.Basic)] // Can't log in with UseDefaultCredentials
+        public async Task AuthTypes_UnathorizedAuthenticatedAuthType_Unauthorized(AuthenticationSchemes authType)
+        {
+            string address;
+            using (Utilities.CreateHttpAuthServer(authType, out address, env =>
+            {
+                var context = new DefaultHttpContext((IFeatureCollection)env);
+                Assert.NotNull(context.User);
+                Assert.True(context.User.Identity.IsAuthenticated);
+                return context.Authentication.ChallengeAsync(authType.ToString(), null, ChallengeBehavior.Unauthorized);
+            }))
+            {
+                var response = await SendRequestAsync(address, useDefaultCredentials: true);
+                Assert.Equal(HttpStatusCode.Unauthorized, response.StatusCode);
+                Assert.Equal(1, response.Headers.WwwAuthenticate.Count);
+                Assert.Equal(authType.ToString(), response.Headers.WwwAuthenticate.First().Scheme);
+            }
+        }
+
         private async Task<HttpResponseMessage> SendRequestAsync(string uri, bool useDefaultCredentials = false)
         {
             HttpClientHandler handler = new HttpClientHandler();