AuthorizeFilter 失败时如何返回 403 而不是重定向访问被拒绝

Question

在 Startup.ConfigureServices() 我这样配置授权过滤器：

services.AddMvc(options =>
{
    options.Filters.Add(new AuthorizeFilter(myAuthorizationPolicy));
})

我使用 cookie 身份验证或基于配置的 AAD 身份验证：

if (useCookieAuth)
{
    services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
        .AddCookie();
}
else
{
    services.AddAuthentication(AzureADDefaults.AuthenticationScheme)
       .AddAzureAD(options => Configuration.Bind("Authentication:AzureAd", options));
}

现在，当我访问一个页面并且 myAuthorizationPolicy 失败时，我被重定向到“Account/AccessDenied?ReturnUrl=%2F”，但我想返回 403。

Answer 1

public class AuthorizeOrForbidAttribute : AuthorizeAttribute
{
    protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
    {
        if (!filterContext.HttpContext.User.Identity.IsAuthenticated)
        {
            filterContext.Result = new HttpStatusCodeResult(403);
        }

    }
}

试试上面的过滤器。

Answer 2

看来你必须重写 OnRedirectToAccessDenied

services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
    .AddCookie(options => {
        options.Events.OnRedirectToAccessDenied = context => {
             context.Response.StatusCode = 403;
             return Task.CompletedTask;
        };
    });

Answer 3

您可以结合您的策略创建自定义 Authorization Filter。

public class MyAuthorizeFilter: IAsyncAuthorizationFilter
{
    public MyAuthorizeFilter(string policy)
    {
        Policy = policy;
    }

    public string Policy { get; set; }
    public async Task OnAuthorizationAsync(AuthorizationFilterContext context)
    {
        var user = context.HttpContext.User;

        var authZService = context.HttpContext.RequestServices.GetRequiredService<IAuthorizationService>();
        var accessable = await authZService.AuthorizeAsync(user, null, this.Policy);
        if (!accessable.Succeeded)
        {
            context.HttpContext.Response.StatusCode = (int)HttpStatusCode.Forbidden;
        }

    }
}

现在你可以使用授权过滤器来拦截请求了：

[MyAuthorizeFilter("MyPolicy")]
public IActionResult Index()

或全局：

services.AddMvc(options =>
        {
            options.Filters.Add(new MyAuthorizeFilter("MyPolicy"));              
        });

当然，我们需要先注册策略。

services.AddAuthorization(o => {
            o.AddPolicy("MyPolicy", pb => {
                pb.RequireAuthenticatedUser();
                //...
            });
        });

Answer 4

我最近遇到了这个问题，并且能够在以下位置找到有关如何覆盖 AzureADB2C 中默认 cookie 行为的说明：

https://docs.microsoft.com/en-us/aspnet/core/security/authentication/azure-ad-b2c?view=aspnetcore-3.1#configure-the-underlying-openidconnectoptionsjwtbearercookie-options

这是一个实现该覆盖以返回简单 403 而不是重定向的示例：

services
    .AddAuthentication(AzureADB2CDefaults.AuthenticationScheme)
    .AddAzureADB2C();

services.Configure<CookieAuthenticationOptions> (AzureADB2CDefaults.CookieScheme, options =>
{
    // Stop AzureADB2C from redirecting 403's, which it does by default.  We just want to return the 403.
    options.Events.OnRedirectToAccessDenied = new Func<RedirectContext<CookieAuthenticationOptions>, Task>(context =>
    {
        context.Response.StatusCode = StatusCodes.Status403Forbidden;
        return context.Response.CompleteAsync();
    });
});

希望这对某人有所帮助。

Answer 5

对于那些使用 Azure AD 并在他们的ConfigureServices 中使用的人（咳嗽我）：

services.AddMicrosoftIdentityWebAppAuthentication(Configuration);

解决方法如下：

        services.Configure<CookieAuthenticationOptions>(CookieAuthenticationDefaults.AuthenticationScheme, options =>
        {
            options.Events.OnRedirectToAccessDenied = new Func<RedirectContext<CookieAuthenticationOptions>, Task>(context =>
            {
                context.Response.StatusCode = StatusCodes.Status403Forbidden;
                return context.Response.CompleteAsync();
            });
        });

这样，ASP.NET 将不再重定向到AccessDenied，而是返回403。

更多细节可以在这里找到：https://blog.johnnyreilly.com/2020/12/21/how-to-make-azure-ad-403/（但我希望你真正需要的只是这个答案）