Update the authorization/logout validation/handling events to expose the ClaimsPrincipal resolved from id_token_hint

src/OpenIddict.Server/OpenIddictServerEvents.Authentication.cs

@@ -76,6 +76,13 @@ namespace OpenIddict.Server
 
                 RedirectUri = address;
             }
+
+            /// <summary>
+            /// Gets or sets the security principal extracted from the id_token_hint, if available.
+            /// Note: the principal may not represent the user currently logged in,
+            /// so additional validation is strongly encouraged when using this property.
+            /// </summary>
+            public ClaimsPrincipal IdentityTokenHintPrincipal { get; set; }
         }
 
         /// <summary>
@@ -91,6 +98,13 @@ namespace OpenIddict.Server
                 : base(transaction)
             {
             }
+
+            /// <summary>
+            /// Gets or sets the security principal extracted from the id_token_hint, if available.
+            /// Note: the principal may not represent the user currently logged in,
+            /// so additional validation is strongly encouraged when using this property.
+            /// </summary>
+            public ClaimsPrincipal IdentityTokenHintPrincipal { get; set; }
         }
 
         /// <summary>

src/OpenIddict.Server/OpenIddictServerEvents.Session.cs

@@ -5,6 +5,7 @@
  */
 
 using System;
+using System.Security.Claims;
 using JetBrains.Annotations;
 
 namespace OpenIddict.Server
@@ -68,6 +69,13 @@ namespace OpenIddict.Server
 
                 PostLogoutRedirectUri = address;
             }
+
+            /// <summary>
+            /// Gets or sets the security principal extracted from the id_token_hint, if available.
+            /// Note: the principal may not represent the user currently logged in,
+            /// so additional validation is strongly encouraged when using this property.
+            /// </summary>
+            public ClaimsPrincipal IdentityTokenHintPrincipal { get; set; }
         }
 
         /// <summary>
@@ -85,14 +93,11 @@ namespace OpenIddict.Server
             }
 
             /// <summary>
-            /// Gets a boolean indicating whether the logout request should be processed.
-            /// </summary>
-            public bool IsLogoutAllowed { get; private set; }
-
-            /// <summary>
-            /// Allow the logout request to be processed.
+            /// Gets or sets the security principal extracted from the id_token_hint, if available.
+            /// Note: the principal may not represent the user currently logged in,
+            /// so additional validation is strongly encouraged when using this property.
             /// </summary>
-            public void ProcessLogout() => IsLogoutAllowed = true;
+            public ClaimsPrincipal IdentityTokenHintPrincipal { get; set; }
         }
 
         /// <summary>

src/OpenIddict.Server/OpenIddictServerHandlers.Authentication.cs

@@ -6,6 +6,7 @@
 
 using System;
 using System.Collections.Immutable;
+using System.Security.Claims;
 using System.Text;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
@@ -55,6 +56,11 @@ namespace OpenIddict.Server
                 ValidateGrantTypePermissions.Descriptor,
                 ValidateScopePermissions.Descriptor,
 
+                /*
+                 * Authorization request handling:
+                 */
+                AttachIdentityTokenHintPrincipal.Descriptor,
+
                 /*
                  * Authorization response processing:
                  */
@@ -1027,7 +1033,9 @@ namespace OpenIddict.Server
 
                     // Note: the expiration date associated with an identity token used as an id_token_hint is deliberately ignored.
 
-                    // Store the security principal extracted from the identity token as an environment property.
+                    // Attach the security principal extracted from the identity token to the
+                    // validation context and store it as an environment property.
+                    context.IdentityTokenHintPrincipal = notification.Principal;
                     context.Transaction.Properties[Properties.AmbientPrincipal] = notification.Principal;
                 }
             }
@@ -1541,6 +1549,43 @@ namespace OpenIddict.Server
                 }
             }
 
+            /// <summary>
+            /// Contains the logic responsible of attaching the principal extracted from the id_token_hint to the event context.
+            /// </summary>
+            public class AttachIdentityTokenHintPrincipal : IOpenIddictServerHandler<HandleAuthorizationRequestContext>
+            {
+                /// <summary>
+                /// Gets the default descriptor definition assigned to this handler.
+                /// </summary>
+                public static OpenIddictServerHandlerDescriptor Descriptor { get; }
+                    = OpenIddictServerHandlerDescriptor.CreateBuilder<HandleAuthorizationRequestContext>()
+                        .UseSingletonHandler<AttachIdentityTokenHintPrincipal>()
+                        .SetOrder(int.MinValue + 100_000)
+                        .Build();
+
+                /// <summary>
+                /// Processes the event.
+                /// </summary>
+                /// <param name="context">The context associated with the event to process.</param>
+                /// <returns>
+                /// A <see cref="ValueTask"/> that can be used to monitor the asynchronous operation.
+                /// </returns>
+                public ValueTask HandleAsync([NotNull] HandleAuthorizationRequestContext context)
+                {
+                    if (context == null)
+                    {
+                        throw new ArgumentNullException(nameof(context));
+                    }
+
+                    if (context.Transaction.Properties.TryGetValue(Properties.AmbientPrincipal, out var principal))
+                    {
+                        context.IdentityTokenHintPrincipal ??= (ClaimsPrincipal) principal;
+                    }
+
+                    return default;
+                }
+            }
+
             /// <summary>
             /// Contains the logic responsible of inferring the redirect URL
             /// used to send the response back to the client application.

src/OpenIddict.Server/OpenIddictServerHandlers.Session.cs

@@ -6,6 +6,7 @@
 
 using System;
 using System.Collections.Immutable;
+using System.Security.Claims;
 using System.Text;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
@@ -40,6 +41,11 @@ namespace OpenIddict.Server
                 ValidateIdTokenHint.Descriptor,
                 ValidateClientPostLogoutRedirectUri.Descriptor,
 
+                /*
+                 * Logout request handling:
+                 */
+                AttachIdentityTokenHintPrincipal.Descriptor,
+
                 /*
                  * Logout response processing:
                  */
@@ -255,26 +261,23 @@ namespace OpenIddict.Server
                         return;
                     }
 
-                    if (notification.IsLogoutAllowed)
+                    var @event = new ProcessSignoutContext(context.Transaction)
                     {
-                        var @event = new ProcessSignoutContext(context.Transaction)
-                        {
-                            Response = new OpenIddictResponse()
-                        };
+                        Response = new OpenIddictResponse()
+                    };
 
-                        await _provider.DispatchAsync(@event);
+                    await _provider.DispatchAsync(@event);
 
-                        if (@event.IsRequestHandled)
-                        {
-                            context.HandleRequest();
-                            return;
-                        }
+                    if (@event.IsRequestHandled)
+                    {
+                        context.HandleRequest();
+                        return;
+                    }
 
-                        else if (@event.IsRequestSkipped)
-                        {
-                            context.SkipRequest();
-                            return;
-                        }
+                    else if (@event.IsRequestSkipped)
+                    {
+                        context.SkipRequest();
+                        return;
                     }
 
                     throw new InvalidOperationException(new StringBuilder()
@@ -459,7 +462,9 @@ namespace OpenIddict.Server
 
                     // Note: the expiration date associated with an identity token used as an id_token_hint is deliberately ignored.
 
-                    // Store the security principal extracted from the identity token as an environment property.
+                    // Attach the security principal extracted from the identity token to the
+                    // validation context and store it as an environment property.
+                    context.IdentityTokenHintPrincipal = notification.Principal;
                     context.Transaction.Properties[Properties.AmbientPrincipal] = notification.Principal;
                 }
             }
@@ -549,6 +554,43 @@ namespace OpenIddict.Server
                 }
             }
 
+            /// <summary>
+            /// Contains the logic responsible of attaching the principal extracted from the id_token_hint to the event context.
+            /// </summary>
+            public class AttachIdentityTokenHintPrincipal : IOpenIddictServerHandler<HandleLogoutRequestContext>
+            {
+                /// <summary>
+                /// Gets the default descriptor definition assigned to this handler.
+                /// </summary>
+                public static OpenIddictServerHandlerDescriptor Descriptor { get; }
+                    = OpenIddictServerHandlerDescriptor.CreateBuilder<HandleLogoutRequestContext>()
+                        .UseSingletonHandler<AttachIdentityTokenHintPrincipal>()
+                        .SetOrder(int.MinValue + 100_000)
+                        .Build();
+
+                /// <summary>
+                /// Processes the event.
+                /// </summary>
+                /// <param name="context">The context associated with the event to process.</param>
+                /// <returns>
+                /// A <see cref="ValueTask"/> that can be used to monitor the asynchronous operation.
+                /// </returns>
+                public ValueTask HandleAsync([NotNull] HandleLogoutRequestContext context)
+                {
+                    if (context == null)
+                    {
+                        throw new ArgumentNullException(nameof(context));
+                    }
+
+                    if (context.Transaction.Properties.TryGetValue(Properties.AmbientPrincipal, out var principal))
+                    {
+                        context.IdentityTokenHintPrincipal ??= (ClaimsPrincipal) principal;
+                    }
+
+                    return default;
+                }
+            }
+
             /// <summary>
             /// Contains the logic responsible of inferring the redirect URL
             /// used to send the response back to the client application.