Add AccessDeniedPath support to the OIDC/OAuth2/Twitter providers

samples/OpenIdConnectSample/Startup.cs

@@ -63,6 +63,7 @@ public void ConfigureServices(IServiceCollection services)
                 o.ResponseType = OpenIdConnectResponseType.CodeIdToken;
                 o.SaveTokens = true;
                 o.GetClaimsFromUserInfoEndpoint = true;
+                o.AccessDeniedPath = "/access-denied-from-remote";
 
                 o.ClaimActions.MapAllExcept("aud", "iss", "iat", "nbf", "exp", "aio", "c_hash", "uti", "nonce");
 
@@ -126,6 +127,16 @@ await context.SignOutAsync(OpenIdConnectDefaults.AuthenticationScheme, new Authe
                     return;
                 }
 
+                if (context.Request.Path.Equals("/access-denied-from-remote"))
+                {
+                    await WriteHtmlAsync(response, async res =>
+                    {
+                        await res.WriteAsync($"<h1>Access Denied error received from the remote authorization server</h1>");
+                        await res.WriteAsync("<a class=\"btn btn-default\" href=\"/\">Home</a>");
+                    });
+                    return;
+                }
+
                 if (context.Request.Path.Equals("/Account/AccessDenied"))
                 {
                     await context.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);

src/Microsoft.AspNetCore.Authentication.OAuth/OAuthHandler.cs

@@ -63,6 +63,17 @@ protected override async Task<HandleRequestResult> HandleRemoteAuthenticateAsync
             var error = query["error"];
             if (!StringValues.IsNullOrEmpty(error))
             {
+                // Note: access_denied errors are special protocol errors indicating the user didn't
+                // approve the authorization demand requested by the remote authorization server.
+                // Since it's a frequent scenario (that is not caused by incorrect configuration),
+                // denied errors are handled differently using a special "access denied" exception.
+                // Visit https://tools.ietf.org/html/rfc6749#section-4.1.2.1 for more information.
+                if (StringValues.Equals(error, "access_denied"))
+                {
+                    return HandleRequestResult.Fail(new AccessDeniedException(
+                        "Access was denied by the resource owner or by the remote server."), properties);
+                }
+
                 var failureMessage = new StringBuilder();
                 failureMessage.Append(error);
                 var errorDescription = query["error_description"];
@@ -194,7 +205,7 @@ protected override async Task HandleChallengeAsync(AuthenticationProperties prop
         {
             if (string.IsNullOrEmpty(properties.RedirectUri))
             {
-                properties.RedirectUri = CurrentUri;
+                properties.RedirectUri = OriginalPathBase + Request.Path + Request.QueryString;
             }
 
             // OAuth2 10.12 CSRF

src/Microsoft.AspNetCore.Authentication.OAuth/OAuthOptions.cs

@@ -3,11 +3,9 @@
 
 using System;
 using System.Collections.Generic;
-using Microsoft.AspNetCore.Authentication;
-using Microsoft.AspNetCore.Authentication.OAuth;
-using Microsoft.AspNetCore.Authentication.OAuth.Claims;
-using Microsoft.AspNetCore.Http.Authentication;
 using System.Globalization;
+using Microsoft.AspNetCore.Authentication.OAuth.Claims;
+using Microsoft.AspNetCore.Http;
 
 namespace Microsoft.AspNetCore.Authentication.OAuth
 {

src/Microsoft.AspNetCore.Authentication.OpenIdConnect/OpenIdConnectHandler.cs

@@ -186,7 +186,7 @@ public async virtual Task SignOutAsync(AuthenticationProperties properties)
                 properties.RedirectUri = BuildRedirectUriIfRelative(Options.SignedOutRedirectUri);
                 if (string.IsNullOrWhiteSpace(properties.RedirectUri))
                 {
-                    properties.RedirectUri = CurrentUri;
+                    properties.RedirectUri = OriginalPathBase + Request.Path + Request.QueryString;
                 }
             }
             Logger.PostSignOutRedirect(properties.RedirectUri);
@@ -312,7 +312,7 @@ protected override async Task HandleChallengeAsync(AuthenticationProperties prop
             // 2. CurrentUri if RedirectUri is not set)
             if (string.IsNullOrEmpty(properties.RedirectUri))
             {
-                properties.RedirectUri = CurrentUri;
+                properties.RedirectUri = OriginalPathBase + Request.Path + Request.QueryString;
             }
             Logger.PostAuthenticationLocalRedirect(properties.RedirectUri);
 
@@ -520,6 +520,17 @@ protected override async Task<HandleRequestResult> HandleRemoteAuthenticateAsync
                 // if any of the error fields are set, throw error null
                 if (!string.IsNullOrEmpty(authorizationResponse.Error))
                 {
+                    // Note: access_denied errors are special protocol errors indicating the user didn't
+                    // approve the authorization demand requested by the remote authorization server.
+                    // Since it's a frequent scenario (that is not caused by incorrect configuration),
+                    // denied errors are handled differently using a special "access denied" exception.
+                    // Visit https://tools.ietf.org/html/rfc6749#section-4.1.2.1 for more information.
+                    if (string.Equals(authorizationResponse.Error, "access_denied", StringComparison.Ordinal))
+                    {
+                        return HandleRequestResult.Fail(new AccessDeniedException(
+                            "Access was denied by the resource owner or by the remote server."), properties);
+                    }
+
                     return HandleRequestResult.Fail(CreateOpenIdConnectProtocolException(authorizationResponse, response: null), properties);
                 }
 

src/Microsoft.AspNetCore.Authentication.Twitter/TwitterHandler.cs

@@ -55,12 +55,14 @@ protected override async Task<HandleRequestResult> HandleRemoteAuthenticateAsync
 
             var properties = requestToken.Properties;
 
-            // REVIEW: see which of these are really errors
-
             var denied = query["denied"];
             if (!StringValues.IsNullOrEmpty(denied))
             {
-                return HandleRequestResult.Fail("The user denied permissions.", properties);
+                // Note: denied errors are special protocol errors indicating the user didn't
+                // approve the authorization demand requested by the remote authorization server.
+                // Since it's a frequent scenario (that is not caused by incorrect configuration),
+                // denied errors are handled differently using a special "access denied" exception.
+                return HandleRequestResult.Fail(new AccessDeniedException("The user denied permissions."), properties);
             }
 
             var returnedToken = query["oauth_token"];
@@ -130,7 +132,7 @@ protected override async Task HandleChallengeAsync(AuthenticationProperties prop
         {
             if (string.IsNullOrEmpty(properties.RedirectUri))
             {
-                properties.RedirectUri = CurrentUri;
+                properties.RedirectUri = OriginalPathBase + Request.Path + Request.QueryString;
             }
 
             // If CallbackConfirmed is false, this will throw

src/Microsoft.AspNetCore.Authentication.Twitter/TwitterOptions.cs

@@ -2,8 +2,8 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Security.Claims;
 using System.Globalization;
+using System.Security.Claims;
 using Microsoft.AspNetCore.Authentication.OAuth.Claims;
 using Microsoft.AspNetCore.Http;
 

src/Microsoft.AspNetCore.Authentication.WsFederation/WsFederationHandler.cs

@@ -83,7 +83,7 @@ protected override async Task HandleChallengeAsync(AuthenticationProperties prop
             // Save the original challenge URI so we can redirect back to it when we're done.
             if (string.IsNullOrEmpty(properties.RedirectUri))
             {
-                properties.RedirectUri = CurrentUri;
+                properties.RedirectUri = OriginalPathBase + Request.Path + Request.QueryString;
             }
 
             var wsFederationMessage = new WsFederationMessage()

src/Microsoft.AspNetCore.Authentication/Events/AccessDeniedContext.cs

@@ -0,0 +1,33 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Authentication
+{
+    /// <summary>
+    /// Provides access denied failure context information to handler providers.
+    /// </summary>
+    public class AccessDeniedContext : HandleRequestContext<RemoteAuthenticationOptions>
+    {
+        public AccessDeniedContext(
+            HttpContext context,
+            AuthenticationScheme scheme,
+            RemoteAuthenticationOptions options,
+            AccessDeniedException failure)
+            : base(context, scheme, options)
+        {
+            Failure = failure;
+        }
+
+        /// <summary>
+        /// User friendly error message for the error.
+        /// </summary>
+        public AccessDeniedException Failure { get; set; }
+
+        /// <summary>
+        /// Additional state values for the authentication session.
+        /// </summary>
+        public AuthenticationProperties Properties { get; set; }
+    }
+}

src/Microsoft.AspNetCore.Authentication/Events/RemoteAuthenticationEvents.cs

@@ -8,12 +8,18 @@ namespace Microsoft.AspNetCore.Authentication
 {
     public class RemoteAuthenticationEvents
     {
+        public Func<AccessDeniedContext, Task> OnAccessDenied { get; set; } = context => Task.CompletedTask;
         public Func<RemoteFailureContext, Task> OnRemoteFailure { get; set; } = context => Task.CompletedTask;
 
         public Func<TicketReceivedContext, Task> OnTicketReceived { get; set; } = context => Task.CompletedTask;
 
         /// <summary>
-        /// Invoked when there is a remote failure
+        /// Invoked when an access denied error was returned by the remote server.
+        /// </summary>
+        public virtual Task AccessDenied(AccessDeniedContext context) => OnAccessDenied(context);
+
+        /// <summary>
+        /// Invoked when there is a remote failure.
         /// </summary>
         public virtual Task RemoteFailure(RemoteFailureContext context) => OnRemoteFailure(context);
 

src/Microsoft.AspNetCore.Authentication/Exceptions/AccessDeniedException.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace Microsoft.AspNetCore.Authentication
+{
+    /// <summary>
+    /// Represents a special exception thrown when an external
+    /// authorization demand was denied by the remote server. 
+    /// </summary>
+    public class AccessDeniedException : Exception
+    {
+        public AccessDeniedException(string message)
+            : base(message)
+        {
+        }
+    }
+}

src/Microsoft.AspNetCore.Authentication/LoggingExtensions.cs

@@ -7,17 +7,18 @@ namespace Microsoft.Extensions.Logging
 {
     internal static class LoggingExtensions
     {
-        private static Action<ILogger, string, Exception> _authSchemeAuthenticated;
-        private static Action<ILogger, string, Exception> _authSchemeNotAuthenticated;
-        private static Action<ILogger, string, string, Exception> _authSchemeNotAuthenticatedWithFailure;
-        private static Action<ILogger, string, Exception> _authSchemeChallenged;
-        private static Action<ILogger, string, Exception> _authSchemeForbidden;
-        private static Action<ILogger, string, Exception> _remoteAuthenticationError;
-        private static Action<ILogger, Exception> _signInHandled;
-        private static Action<ILogger, Exception> _signInSkipped;
-        private static Action<ILogger, string, Exception> _correlationPropertyNotFound;
-        private static Action<ILogger, string, Exception> _correlationCookieNotFound;
-        private static Action<ILogger, string, string, Exception> _unexpectedCorrelationCookieValue;
+        private static readonly Action<ILogger, string, Exception> _authSchemeAuthenticated;
+        private static readonly Action<ILogger, string, Exception> _authSchemeNotAuthenticated;
+        private static readonly Action<ILogger, string, string, Exception> _authSchemeNotAuthenticatedWithFailure;
+        private static readonly Action<ILogger, string, Exception> _authSchemeChallenged;
+        private static readonly Action<ILogger, string, Exception> _authSchemeForbidden;
+        private static readonly Action<ILogger, string, Exception> _remoteAuthenticationError;
+        private static readonly Action<ILogger, Exception> _signInHandled;
+        private static readonly Action<ILogger, Exception> _signInSkipped;
+        private static readonly Action<ILogger, string, Exception> _correlationPropertyNotFound;
+        private static readonly Action<ILogger, string, Exception> _correlationCookieNotFound;
+        private static readonly Action<ILogger, string, string, Exception> _unexpectedCorrelationCookieValue;
+        private static readonly Action<ILogger, Exception> _accessDeniedError;
 
         static LoggingExtensions()
         {
@@ -65,6 +66,10 @@ static LoggingExtensions()
                eventId: 16,
                logLevel: LogLevel.Warning,
                formatString: "The correlation cookie value '{CorrelationCookieName}' did not match the expected value '{CorrelationCookieValue}'.");
+            _accessDeniedError = LoggerMessage.Define(
+                eventId: 17,
+                logLevel: LogLevel.Information,
+                formatString: "Access was denied by the resource owner or by the remote server.");
         }
 
         public static void AuthenticationSchemeAuthenticated(this ILogger logger, string authenticationScheme)
@@ -121,5 +126,10 @@ public static void UnexpectedCorrelationCookieValue(this ILogger logger, string
         {
             _unexpectedCorrelationCookieValue(logger, cookieName, cookieValue, null);
         }
+
+        public static void AccessDeniedError(this ILogger logger)
+        {
+            _accessDeniedError(logger, null);
+        }
     }
 }

src/Microsoft.AspNetCore.Authentication/RemoteAuthenticationHandler.cs

@@ -5,6 +5,7 @@
 using System.Security.Cryptography;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.WebUtilities;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 
@@ -80,6 +81,46 @@ public virtual async Task<bool> HandleRequestAsync()
 
             if (exception != null)
             {
+                if (exception is AccessDeniedException ex)
+                {
+                    Logger.AccessDeniedError();
+                    var accessDeniedContext = new AccessDeniedContext(Context, Scheme, Options, ex)
+                    {
+                        Properties = properties
+                    };
+                    await Events.AccessDenied(accessDeniedContext);
+
+                    if (accessDeniedContext.Result != null)
+                    {
+                        if (accessDeniedContext.Result.Handled)
+                        {
+                            return true;
+                        }
+                        else if (accessDeniedContext.Result.Skipped)
+                        {
+                            return false;
+                        }
+                        else if (accessDeniedContext.Result.Failure != null)
+                        {
+                            throw new Exception("An error was returned from the AccessDenied event.", accessDeniedContext.Result.Failure);
+                        }
+                    }
+
+                    // If an access denied endpoint was specified, redirect the user agent.
+                    // Otherwise, invoke the RemoteFailure event for further processing.
+                    if (Options.AccessDeniedPath.HasValue)
+                    {
+                        string uri = Options.AccessDeniedPath;
+                        if (!string.IsNullOrEmpty(Options.ReturnUrlParameter) && !string.IsNullOrEmpty(properties?.RedirectUri))
+                        {
+                            uri = QueryHelpers.AddQueryString(uri, Options.ReturnUrlParameter, properties.RedirectUri);
+                        }
+                        Response.Redirect(uri);
+
+                        return true;
+                    }
+                }
+
                 Logger.RemoteAuthenticationError(exception.Message);
                 var errorContext = new RemoteFailureContext(Context, Scheme, Options, exception)
                 {

src/Microsoft.AspNetCore.Authentication/RemoteAuthenticationOptions.cs

@@ -89,6 +89,22 @@ public override void Validate()
         /// </summary>
         public PathString CallbackPath { get; set; }
 
+        /// <summary>
+        /// Gets or sets the optional path the user agent is redirected to if the user
+        /// doesn't approve the authorization demand requested by the remote server.
+        /// This property is not set by default. In this case, an exception is thrown
+        /// if an access_denied response is returned by the remote authorization server.
+        /// </summary>
+        public PathString AccessDeniedPath { get; set; }
+
+        /// <summary>
+        /// Gets or sets the name of the parameter used to convey the original location
+        /// of the user before the remote challenge was triggered up to the access denied page.
+        /// This property is only used when the <see cref="AccessDeniedPath"/> is explicitly specified.
+        /// </summary>
+        // Note: this deliberately matches the default parameter name used by the cookie handler.
+        public string ReturnUrlParameter { get; set; } = "ReturnUrl";
+
         /// <summary>
         /// Gets or sets the authentication scheme corresponding to the middleware
         /// responsible of persisting user's identity after a successful authentication.

test/Microsoft.AspNetCore.Authentication.Test/GoogleTests.cs

@@ -378,7 +378,7 @@ public async Task ReplyPathWithErrorFails(bool redirect)
                 } : new OAuthEvents();
             });
             var sendTask = server.SendAsync("https://example.com/signin-google?error=OMG&error_description=SoBad&error_uri=foobar&state=protected_state",
-                ".AspNetCore.Correlation.Google.corrilationId=N");
+                ".AspNetCore.Correlation.Google.correlationId=N");
             if (redirect)
             {
                 var transaction = await sendTask;
@@ -1205,7 +1205,7 @@ public AuthenticationProperties Unprotect(string protectedText)
                 Assert.Equal("protected_state", protectedText);
                 var properties = new AuthenticationProperties(new Dictionary<string, string>()
                 {
-                    { ".xsrf", "corrilationId" },
+                    { ".xsrf", "correlationId" },
                     { "testkey", "testvalue" }
                 });
                 properties.RedirectUri = "http://testhost/redirect";