Fix hangs when auth scheme is NTLM/Negotiate

Author: stephentoub

src/System.Net.HttpListener/src/System/Net/Managed/ListenerAsyncResult.Managed.cs

@@ -112,7 +112,7 @@ internal void Complete(HttpListenerContext context, bool synch)
             _context = context;
             lock (_locker)
             {
-                bool selectionFailure = false;
+                bool authFailure = false;
                 try
                 {
                     context.AuthenticationSchemes = context._listener.SelectAuthenticationScheme(context);
@@ -124,18 +124,26 @@ internal void Complete(HttpListenerContext context, bool synch)
                 }
                 catch
                 {
-                    selectionFailure = true;
+                    authFailure = true;
                     context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
                 }
 
-                if (selectionFailure || 
-                    ((context.AuthenticationSchemes == AuthenticationSchemes.Basic || context._listener.AuthenticationSchemes == AuthenticationSchemes.Negotiate) && context.Request.Headers["Authorization"] == null))
+                if (context.AuthenticationSchemes != AuthenticationSchemes.None &&
+                    (context.AuthenticationSchemes & AuthenticationSchemes.Anonymous) != AuthenticationSchemes.Anonymous &&
+                    (context.AuthenticationSchemes & AuthenticationSchemes.Basic) != AuthenticationSchemes.Basic)
+                {
+                    authFailure = true;
+                    context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
+                }
+                else if (context.AuthenticationSchemes == AuthenticationSchemes.Basic && context.Request.Headers["Authorization"] == null)
+                {
+                    authFailure = true;
+                    context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
+                    context.Response.Headers["WWW-Authenticate"] = context.AuthenticationSchemes + " realm=\"" + context._listener.Realm + "\"";
+                }
+
+                if (authFailure)
                 {
-                    if (!selectionFailure)
-                    {
-                        context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
-                        context.Response.Headers["WWW-Authenticate"] = context.AuthenticationSchemes + " realm=\"" + context._listener.Realm + "\"";
-                    }
                     context.Response.OutputStream.Close();
                     IAsyncResult ares = context._listener.BeginGetContext(_cb, _state);
                     _forward = (ListenerAsyncResult)ares;

src/System.Net.HttpListener/tests/AuthenticationTests.cs

@@ -134,7 +134,7 @@ public async Task TestAnonymousAuthenticationWithDelegate()
             await ValidateNullUser();
         }
 
-        [ConditionalFact(nameof(Helpers) + "." + nameof(Helpers.IsWindowsImplementation))] // [ActiveIssue(20101, TestPlatforms.AnyUnix)]
+        [ConditionalFact(nameof(Helpers) + "." + nameof(Helpers.IsWindowsImplementation))] // [PlatformSpecific(TestPlatforms.Windows, "Managed impl doesn't support NTLM")]
         [ActiveIssue(20096)]
         public async Task NtlmAuthentication_Conversation_ReturnsExpectedType2Message()
         {
@@ -157,7 +157,7 @@ public static IEnumerable<object[]> InvalidNtlmNegotiateAuthentication_TestData(
             yield return new object[] { "abcd", HttpStatusCode.BadRequest };
         }
 
-        [ConditionalTheory(nameof(Helpers) + "." + nameof(Helpers.IsWindowsImplementation))] // [ActiveIssue(20101, TestPlatforms.AnyUnix)]
+        [ConditionalFact(nameof(Helpers) + "." + nameof(Helpers.IsWindowsImplementation))] // [PlatformSpecific(TestPlatforms.Windows, "Managed impl doesn't support NTLM")]
         [ActiveIssue(20096)]
         [MemberData(nameof(InvalidNtlmNegotiateAuthentication_TestData))]
         public async Task NtlmAuthentication_InvalidRequestHeaders_ReturnsExpectedStatusCode(string header, HttpStatusCode statusCode)
@@ -180,7 +180,7 @@ public async Task NtlmAuthentication_InvalidRequestHeaders_ReturnsExpectedStatus
             }
         }
 
-        [ConditionalFact(nameof(Helpers) + "." + nameof(Helpers.IsWindowsImplementation))] // [ActiveIssue(20101, TestPlatforms.AnyUnix)]
+        [ConditionalFact(nameof(Helpers) + "." + nameof(Helpers.IsWindowsImplementation))] // [PlatformSpecific(TestPlatforms.Windows, "Managed impl doesn't support Negotiate")]
         [ActiveIssue(20096)]
         public async Task NegotiateAuthentication_Conversation_ReturnsExpectedType2Message()
         {
@@ -195,7 +195,7 @@ public async Task NegotiateAuthentication_Conversation_ReturnsExpectedType2Messa
             }
         }
 
-        [ConditionalTheory(nameof(Helpers) + "." + nameof(Helpers.IsWindowsImplementation))] // [ActiveIssue(20101, TestPlatforms.AnyUnix)]
+        [ConditionalFact(nameof(Helpers) + "." + nameof(Helpers.IsWindowsImplementation))] // [PlatformSpecific(TestPlatforms.Windows, "Managed impl doesn't support Negotiate")]
         [ActiveIssue(20096)]
         [MemberData(nameof(InvalidNtlmNegotiateAuthentication_TestData))]
         public async Task NegotiateAuthentication_InvalidRequestHeaders_ReturnsExpectedStatusCode(string header, HttpStatusCode statusCode)