Use ImpersonationToken for IIS Windows Auth

src/Servers/IIS/AspNetCoreModuleV2/InProcessRequestHandler/managedexports.cpp

@@ -516,7 +516,13 @@ http_get_authentication_information(
 )
 {
     *pstrAuthType = SysAllocString(pInProcessHandler->QueryHttpContext()->GetUser()->GetAuthenticationType());
+    // prefer GetPrimaryToken over GetImpersonationToken as that's what we've been using since before .NET 10
+    // we'll fallback to GetImpersonationToken if GetPrimaryToken is not available
     *pvToken = pInProcessHandler->QueryHttpContext()->GetUser()->GetPrimaryToken();
+    if (*pvToken == nullptr)
+    {
+        *pvToken = pInProcessHandler->QueryHttpContext()->GetUser()->GetImpersonationToken();
+    }
 
     return S_OK;
 }

src/Servers/IIS/AspNetCoreModuleV2/OutOfProcessRequestHandler/forwardinghandler.cpp

@@ -819,11 +819,20 @@ FORWARDING_HANDLER::GetHeaders(
         (_wcsicmp(m_pW3Context->GetUser()->GetAuthenticationType(), L"negotiate") == 0 ||
             _wcsicmp(m_pW3Context->GetUser()->GetAuthenticationType(), L"ntlm") == 0))
     {
-        if (m_pW3Context->GetUser()->GetPrimaryToken() != nullptr &&
-            m_pW3Context->GetUser()->GetPrimaryToken() != INVALID_HANDLE_VALUE)
+        // prefer GetPrimaryToken over GetImpersonationToken as that's what we've been using since before .NET 10
+        // we'll fallback to GetImpersonationToken if GetPrimaryToken is not available
+        HANDLE authToken = m_pW3Context->GetUser()->GetPrimaryToken();
+        if (authToken == nullptr ||
+            authToken == INVALID_HANDLE_VALUE)
+        {
+            authToken = m_pW3Context->GetUser()->GetImpersonationToken();
+        }
+
+        if (authToken != nullptr &&
+            authToken != INVALID_HANDLE_VALUE)
         {
             HANDLE hTargetTokenHandle = nullptr;
-            RETURN_IF_FAILED(pServerProcess->SetWindowsAuthToken(m_pW3Context->GetUser()->GetPrimaryToken(),
+            RETURN_IF_FAILED(pServerProcess->SetWindowsAuthToken(authToken,
                 &hTargetTokenHandle));
 
             //

src/Servers/IIS/IIS/test/Common.FunctionalTests/Infrastructure/RequiresIISAttribute.cs

@@ -136,7 +136,7 @@ public RequiresIISAttribute(IISCapability capabilities)
                 IsMet &= available;
                 if (!available)
                 {
-                    SkipReason += $"The machine does have {module.Capability} available.";
+                    SkipReason += $"The machine does not have {module.Capability} available.";
                 }
             }
         }

src/Servers/IIS/IIS/test/Common.FunctionalTests/WindowsAuthTests.cs

@@ -2,7 +2,9 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Net;
 using System.Net.Http;
+using System.Security.Principal;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Server.IIS.FunctionalTests.Utilities;
 using Microsoft.AspNetCore.Server.IntegrationTesting;
@@ -58,4 +60,51 @@ public async Task WindowsAuthTest(TestVariant variant)
         Assert.StartsWith("Windows:", responseText);
         Assert.Contains(Environment.UserName, responseText);
     }
+
+    [ConditionalTheory]
+    [RequiresIIS(IISCapability.WindowsAuthentication)]
+    [MemberData(nameof(TestVariants))]
+    public async Task WindowsAuthWithImpersonationLevelTest(TestVariant variant)
+    {
+        var deploymentParameters = Fixture.GetBaseDeploymentParameters(variant);
+        deploymentParameters.SetAnonymousAuth(enabled: false);
+        deploymentParameters.SetWindowsAuth();
+
+        // The default in hosting sets windows auth to true.
+        var deploymentResult = await DeployAsync(deploymentParameters);
+
+        var impersonationLevels = new TokenImpersonationLevel[]
+            {
+                TokenImpersonationLevel.None,
+                TokenImpersonationLevel.Identification,
+                TokenImpersonationLevel.Impersonation,
+                TokenImpersonationLevel.Delegation,
+                TokenImpersonationLevel.Anonymous
+            };
+
+        foreach (var impersonationLevel in impersonationLevels)
+        {
+            // TokenImpersonationLevel is not supported by HttpClient so we need to use HttpWebRequest to test it.
+#pragma warning disable SYSLIB0014 // Type or member is obsolete
+            var request = HttpWebRequest.CreateHttp($"{deploymentResult.HttpClient.BaseAddress}Auth");
+#pragma warning restore SYSLIB0014 // Type or member is obsolete
+            request.ImpersonationLevel = impersonationLevel;
+            request.Method = "GET";
+            request.UseDefaultCredentials = true;
+
+            using var response = request.GetResponse();
+            using var reader = new StreamReader(response.GetResponseStream());
+            var responseText = await reader.ReadToEndAsync();
+
+            try
+            {
+                Assert.StartsWith("Windows:", responseText);
+                Assert.Contains(Environment.UserName, responseText);
+            }
+            catch (Exception ex)
+            {
+                Assert.Fail($"'TokenImpersonationLevel.{impersonationLevel}' failed with: {ex.Message}");
+            }
+        }
+    }
 }