Bring Microsoft.AspNetCore.DataProtection.SystemWeb compatibility mode into the FrameworkServices project

Directory.Packages.props

@@ -98,7 +98,6 @@
     <PackageVersion Include="Microsoft.AspNet.Web.Optimization" Version="1.1.3" />
     <PackageVersion Include="Microsoft.AspNet.Web.Optimization.WebForms" Version="1.1.3" />
     <PackageVersion Include="Microsoft.AspNet.WebApi" Version="5.3.0" />
-    <PackageVersion Include="Microsoft.AspNetCore.DataProtection.SystemWeb" Version="2.3.11" />
     <PackageVersion Include="Microsoft.CodeDom.Providers.DotNetCompilerPlatform" Version="4.1.0" />
     <PackageVersion Include="Microsoft.Extensions.ServiceDiscovery" Version="10.7.0" />
     <PackageVersion Include="Microsoft.jQuery.Unobtrusive.Validation" Version="3.3.0" />

samples/AppConfig/AppConfigFramework/Web.config

@@ -23,7 +23,6 @@
   </system.webServer>
   <system.web>
     <httpRuntime targetFramework="4.8.1" />
-    <machineKey compatibilityMode="Framework45" dataProtectorType="Microsoft.AspNetCore.DataProtection.SystemWeb.CompatibilityDataProtector, Microsoft.AspNetCore.DataProtection.SystemWeb" />
     <compilation debug="true" />
   </system.web>
   <runtime>
@@ -154,4 +153,4 @@
       <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008,40000,40008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=4.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
     </compilers>
   </system.codedom>
-</configuration>
+</configuration>

samples/AuthRemoteIdentity/AuthRemoteIdentityFramework/Web.config

@@ -28,7 +28,6 @@
         <add assembly="netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" />
       </assemblies>
     </compilation>
-    <machineKey compatibilityMode="Framework45" dataProtectorType="Microsoft.AspNetCore.DataProtection.SystemWeb.CompatibilityDataProtector, Microsoft.AspNetCore.DataProtection.SystemWeb" />
     <httpRuntime targetFramework="4.8.1" />
   </system.web>
   <system.webServer>

samples/MachineKey/MachineKeyFramework/Global.asax.cs

@@ -14,6 +14,7 @@ protected void Application_Start()
         {
             HttpApplicationHost.RegisterHost(builder =>
             {
+                builder.AddSystemWebDependencyInjection();
                 builder.AddServiceDefaults();
                 builder.AddDataProtection()
                     .SetApplicationName(MachineKeyExampleHandler.AppName)

samples/MachineKey/MachineKeyFramework/MachineKeyFramework.csproj

@@ -2,9 +2,6 @@
   <PropertyGroup>
     <TargetFramework>net481</TargetFramework>
   </PropertyGroup>
-  <ItemGroup>
-    <PackageReference Include="Microsoft.AspNetCore.DataProtection.SystemWeb" />
-  </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\MachineKeyShared\MachineKeyShared.csproj" />
     <ProjectReference Include="..\..\ServiceDefaults\Samples.ServiceDefaults.csproj" />

samples/MachineKey/MachineKeyFramework/Web.config

@@ -7,7 +7,6 @@
   </system.webServer>
   <system.web>
     <httpRuntime targetFramework="4.8.1" />
-    <machineKey compatibilityMode="Framework45" dataProtectorType="Microsoft.AspNetCore.DataProtection.SystemWeb.CompatibilityDataProtector, Microsoft.AspNetCore.DataProtection.SystemWeb" />
     <compilation debug="true" />
   </system.web>
   <runtime>

samples/SessionRemote/SessionRemoteFramework/Web.config

@@ -15,7 +15,6 @@
   </system.webServer>
   <system.web>
     <httpRuntime targetFramework="4.8.1" />
-    <machineKey compatibilityMode="Framework45" dataProtectorType="Microsoft.AspNetCore.DataProtection.SystemWeb.CompatibilityDataProtector, Microsoft.AspNetCore.DataProtection.SystemWeb" />
     <compilation debug="true" />
   </system.web>
   <runtime>
@@ -146,4 +145,4 @@
       <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008,40000,40008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=4.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
     </compilers>
   </system.codedom>
-</configuration>
+</configuration>

src/Microsoft.AspNetCore.SystemWebAdapters.FrameworkServices/CompatibilityDataProtector.cs

@@ -0,0 +1,118 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.ComponentModel;
+using System.Configuration;
+using System.Security.Cryptography;
+using System.Web;
+using Microsoft.AspNetCore.DataProtection;
+using Microsoft.AspNetCore.SystemWebAdapters.Hosting;
+
+namespace Microsoft.AspNetCore.DataProtection.SystemWeb;
+
+[EditorBrowsable(EditorBrowsableState.Never)]
+public class CompatibilityDataProtector : DataProtector
+{
+    [ThreadStatic]
+    private static bool _suppressPrimaryPurpose;
+
+    private readonly Lazy<IDataProtector> _lazyProtector;
+    private readonly Lazy<IDataProtector> _lazyProtectorSuppressedPrimaryPurpose;
+
+    public CompatibilityDataProtector(string applicationName, string primaryPurpose, string[] specificPurposes)
+        : base("application-name", "primary-purpose", null) // we feed dummy values to the base ctor
+    {
+        // We don't want to evaluate the IDataProtectionProvider factory quite yet,
+        // as we'd rather defer failures to the call to Protect so that we can bubble
+        // up a good error message to the developer.
+
+        _lazyProtector = new Lazy<IDataProtector>(() => GetDataProtectionProvider().CreateProtector(primaryPurpose, specificPurposes));
+
+        // System.Web always provides "User.MachineKey.Protect" as the primary purpose for calls
+        // to MachineKey.Protect. Only in this case should we allow suppressing the primary
+        // purpose, as then we can easily map calls to MachineKey.Protect(userData, purposes)
+        // into calls to provider.GetProtector(purposes).Protect(userData).
+        if (primaryPurpose == "User.MachineKey.Protect")
+        {
+            _lazyProtectorSuppressedPrimaryPurpose = new Lazy<IDataProtector>(() => GetDataProtectionProvider().CreateProtector(specificPurposes));
+        }
+        else
+        {
+            _lazyProtectorSuppressedPrimaryPurpose = _lazyProtector;
+        }
+    }
+
+    // We take care of flowing purposes ourselves.
+    protected override bool PrependHashedPurposeToPlaintext => false;
+
+    // Retrieves the appropriate protector (potentially with a suppressed primary purpose) for this operation.
+    private IDataProtector Protector => ((_suppressPrimaryPurpose) ? _lazyProtectorSuppressedPrimaryPurpose : _lazyProtector).Value;
+
+    protected virtual IDataProtectionProvider GetDataProtectionProvider()
+        => HttpApplicationHost.Current.Services.GetDataProtectionProvider();
+
+    public override bool IsReprotectRequired(byte[] encryptedData)
+    {
+        // Nobody ever calls this.
+        return false;
+    }
+
+    protected override byte[] ProviderProtect(byte[] userData)
+    {
+        try
+        {
+            return Protector.Protect(userData);
+        }
+        catch (Exception ex)
+        {
+            // System.Web special-cases ConfigurationException errors and allows them to bubble
+            // up to the developer without being homogenized. Since a call to Protect should
+            // never fail, any exceptions here really do imply a misconfiguration.
+
+#pragma warning disable CS0618 // Type or member is obsolete
+            throw new ConfigurationException("DataProtection failed to protect", ex);
+#pragma warning restore CS0618 // Type or member is obsolete
+        }
+    }
+
+    protected override byte[] ProviderUnprotect(byte[] encryptedData)
+    {
+        return Protector.Unprotect(encryptedData);
+    }
+
+    /// <summary>
+    /// Invokes a delegate where calls to <see cref="ProviderProtect(byte[])"/>
+    /// and <see cref="ProviderUnprotect(byte[])"/> will ignore the primary
+    /// purpose and instead use only the sub-purposes.
+    /// </summary>
+    public static byte[] RunWithSuppressedPrimaryPurpose(Func<object, byte[], byte[]> callback, object state, byte[] input)
+    {
+        if (callback is null)
+        {
+            throw new ArgumentNullException(nameof(callback));
+        }
+
+        if (_suppressPrimaryPurpose)
+        {
+            return callback(state, input); // already suppressed - just forward call
+        }
+
+        try
+        {
+            try
+            {
+                _suppressPrimaryPurpose = true;
+                return callback(state, input);
+            }
+            finally
+            {
+                _suppressPrimaryPurpose = false;
+            }
+        }
+        catch
+        {
+            // defeat exception filters
+            throw;
+        }
+    }
+}

src/Microsoft.AspNetCore.SystemWebAdapters.FrameworkServices/Microsoft.AspNetCore.SystemWebAdapters.FrameworkServices.csproj

@@ -27,7 +27,6 @@
     <PackageReference Include="Microsoft.Extensions.Options.DataAnnotations" />
     <PackageReference Include="System.Text.Json" />
     <PackageReference Include="Microsoft.Extensions.Hosting" />
-    <PackageReference Include="Microsoft.AspNetCore.DataProtection.SystemWeb" />
     <PackageReference Include="Microsoft.AspNetCore.DataProtection" />
   </ItemGroup>
   <ItemGroup>