How can I reject all request except GET request - c#

I am building .NET 5 WebAPI.
I need a filter or policy that rejects all verbs except GET even if the route and the verb do match.
Can I do this in Startup class?

Using MapWhen you can branch based on a predicate:
app.MapWhen(context => !context.Request.Method.Equals("GET", StringComparison.InvariantCultureIgnoreCase),
(IApplicationBuilder builder) =>
{
builder.Run(async context =>
{
await Task.FromResult(context.Response.StatusCode = StatusCodes.Status406NotAcceptable);
});
});

Related

Is it possible to use app.UseWhen() to only have endpoints with specific conditions?

I have this code:
app.UseWhen(context => context.User.Identity?.IsAuthenticated ?? false, applicationBuilder =>
{
app
.MapGet("/User", (HttpContext context) => Json(context.User.Identity, new JsonSerializerOptions()
{
ReferenceHandler = ReferenceHandler.Preserve,
WriteIndented = true
}));
});
I would expect that I could only call /User if the user is authenticated. As it turns out, if the user is not authenticated then this method still returns a value. I would have expected that it would not find this endpoint and thus generate an error. I was actually hoping for an error...
Why does this method still work when a user is not authenticated?
I would like to enable or disable endpoints based on various conditions. In this case, authenticated users. But in other cases the user role would also matter. And some other user claims would be checked this way, disabling endpoints if certain claims are missing. But it doesn't seem to work like this...
Problem is that you are setting up the "main" application (i.e. app) in the conditional branch. You need to setup the applicationBuilder. For example:
app.UseWhen(context => context.Request.Headers.ContainsKey("test"), applicationBuilder =>
{
applicationBuilder.UseRouting();
applicationBuilder.UseEndpoints(routeBuilder =>
{
routeBuilder.MapGet("/User", (HttpContext context) => new { Test = "Ok" });
});
});
In the example above "/User" route will result in 404 Not Found HTTP Status when there is no test header provided and in 200 OK json result if there is one.

How to enable CORS in Blazor Static Web App?

I have tried every other ways to set Access-Control-Allow-Origin : * in my Blazor Static Web App.
I follow this documentation Configure Azure Static Web Apps first to set globalHeaders. It isn't working.
And I try to add Cors in builder services. It isn't working too.
builder.Services.AddScoped (sp => new HttpClient
{ BaseAddress = new Uri(builder.Configuration["API_Prefix"] ??
builder.HostEnvironment.BaseAddress) });
builder.Services.AddCors(options =>
{ options.AddPolicy(name: policyName,
builder =>
{ builder.WithOrigins("https://localhost:5000") // specifying the allowed origin
.WithMethods("GET") // defining the allowed HTTP method
.AllowAnyHeader(); // allowing any header to be sent
});
});
await builder.Build().RunAsync();
And I tried it also in individual HttpClient request in the following.
// create request object
var request = new HttpRequestMessage(HttpMethod.Get, uri);
// add custom http header
request.Headers.Add("Access-Control-Allow-Origin", "*");
request.Headers.Add("Access-Control-Allow-Methods", "GET");
// send request
var httpResponse = await Http.SendAsync(request);
I had used this tutorial to create [Blazor Static Web App].2
This is the error I got in the browser's console. ].3
What am I missing to set the correct configuration?
Restrict Domain consumption of services by CORS browser restriction. But when you hit the service service will get executed but the response wont captured in browser side. By adding following code in API program.cs will allow specific Domains
builder.Services.AddCors(options =>
{
options.AddDefaultPolicy(policy =>
{
policy.WithOrigins("http://192.168.10.127",
"https://localhost:5000",
"https://localhost:5001")
.AllowAnyHeader()
.AllowAnyMethod();
});
});
app.UseCors();
To allow from any Domain follow below code
app.UseCors(options => options.SetIsOriginAllowed(x => _ = true).AllowAnyMethod().AllowAnyHeader().AllowCredentials());

How to check user-agent in ASP.NET Core health check calls when using own authentication, authorization?

I used the accepted answer to How to check user-agent in ASP.NET Core health check calls (MapHealthChecks)? , with one difference in requirement:
My application is not using App services authentication and authorization. Therefore, I needed to allow anonymous access for healthcheck as per documentation.
Here are changes to Startup.cs
//other services
services.AddHttpContextAccessor();
services.AddScoped<IAuthorizationHandler, UserAgentAuthorizationHandler>();
services.AddHealthChecks()
.AddCheck<HealthCheckFoo>("health_check_foo")
.AddCheck<HealthCheckBar>("health_check_bar");
//other services.AddAuthorization
services.AddAuthorization(options =>
{
options.AddPolicy("HealthCheckPolicy", builder =>
{
builder.AddRequirements(new UserAgentRequirement("HealthCheck/1.0"));
});
});
//...
app.UseEndpoints(endpoints =>
{
//other endpoints...
endpoints.MapHealthChecks("/health", new HealthCheckOptions { AllowCachingResponses = false })
.RequireAuthorization("HealthCheckPolicy");
.WithMetadata(new AllowAnonymousAttribute());
My expectation is that when testing locally, https://localhost:5001/health return an error. It does not.
It looks as your startup class has a mistake on the endpoints.MapHealthChecks adds a RequireAuthorization but as the same time you also add the AllowAnonymousAttribute.
Try with:
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
endpoints.MapHealthChecks("/health", new HealthCheckOptions()
{
AllowCachingResponses = false,
})
.RequireAuthorization("HealthCheckPolicy");
});

How do I add AllowAnonymousAttribute to a route/request from custom midleware?

I have an ASP.NET Core website that is build with static files and ASP.NET Core routing middleware, so no MVC.
I requiring all request to be authenticated by default.
services.AddAuthorization(options =>
{
options.FallbackPolicy = new AuthorizationPolicyBuilder()
.RequireAuthenticatedUser()
.Build();
});
I have a mix of middlewares and routing configuration - but how do I specify that some routes of the static files and my custom middleware needs to Allow Anonymous?
Is there a way to app.Use(...) and tell the context that authorization has been applied and it should not use the fallback? So my custom middlewares can be set up correctly or am I required to set everything up with endpoint routing and added metadata to the routes?
app.UseAuthentication();
app.UseAuthorization();
app.UseMiddleware<NextJSMiddleware>();
app.UseDefaultFiles();
app.UseStaticFiles();
app.UseEndpoints(config =>
{
///This is for detecting whether the application process has crashed/deadlocked. If a liveness probe fails, app can be stopped/restarted, or create a new one.
config.MapHealthChecks("/.well-known/live", new HealthCheckOptions { Predicate = _ => false }).WithMetadata(new AllowAnonymousAttribute()); ;
///Readiness probe. This is for detecting whether the application is ready to handle requests.
config.MapHealthChecks("/.well-known/ready").WithMetadata(new AllowAnonymousAttribute());
config.MapEAVFrameworkRoutes();
config.MapPost("/.auth/login/passwordless", async (httpcontext) =>
{
...
}).WithMetadata(new AllowAnonymousAttribute());
config.MapGet("/.auth/login/passwordless/callback", async (httpcontext) =>
{
...
});
});

ASP.NET Core 2.0 disable automatic challenge

After upgrading my ASP.NET Core project to 2.0, attempts to access protected endpoints no longer returns 401, but redirects to an (non-existing) endpoint in an attempt to let the user authenticate.
The desired behaviour is for the application simply to return a 401. Previously I would set AutomaticChallenge = false when configuring authentication, but according to this article the setting is no longer relevant (in fact it doesn't exist anymore).
My authentication is configured like this:
Startup.cs.ConfigureServices():
services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
.AddCookie(o =>
{
o.Cookie.Name = options.CookieName;
o.Cookie.Domain = options.CookieDomain;
o.SlidingExpiration = true;
o.ExpireTimeSpan = options.CookieLifetime;
o.TicketDataFormat = ticketFormat;
o.CookieManager = new CustomChunkingCookieManager();
});
Configure():
app.UseAuthentication();
How can I disable automatic challenge, so that the application returns 401 when the user is not authenticated?
As pointed out by some of the other answers, there is no longer a setting to turn off automatic challenge with cookie authentication. The solution is to override OnRedirectToLogin:
services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
.AddCookie(options =>
{
options.Events.OnRedirectToLogin = context =>
{
context.Response.Headers["Location"] = context.RedirectUri;
context.Response.StatusCode = 401;
return Task.CompletedTask;
};
});
This may change in the future: https://github.com/aspnet/Security/issues/1394
After some research, I found we can deal with this problem though the bellow approach:
We can add two Authentication scheme both Identity and JWT; and use Identity scheme for authentication and use JWT schema for challenge, JWT will not redirect to any login route while challenge.
services.AddIdentity<ApplicationUser, IdentityRole>().AddEntityFrameworkStores<ApplicationDbContext>();
services.AddAuthentication((cfg =>
{
cfg.DefaultScheme = IdentityConstants.ApplicationScheme;
cfg.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
})).AddJwtBearer();
Similiar to #Serverin, setting the OnRedirectToLogin of the Application Cookie worked, but must be done in statement following services.AddIdentity in Startup.cs:ConfigureServices:
services.ConfigureApplicationCookie(options => {
options.Events.OnRedirectToLogin = context => {
context.Response.Headers["Location"] = context.RedirectUri;
context.Response.StatusCode = 401;
return Task.CompletedTask;
};
});
According to this article:
In 1.x, the AutomaticAuthenticate and AutomaticChallenge properties were intended to be set on a single authentication scheme. There was no good way to enforce this.
In 2.0, these two properties have been removed as flags on the individual AuthenticationOptions instance and have moved into the base AuthenticationOptions class. The properties can be configured in the AddAuthentication method call within the ConfigureServices method of Startup.cs
services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme);
Alternatively, use an overloaded version of the AddAuthentication method to set more than one property. In the following overloaded method example, the default scheme is set to CookieAuthenticationDefaults.AuthenticationScheme. The authentication scheme may alternatively be specified within your individual [Authorize] attributes or authorization policies.
services.AddAuthentication(options => {
options.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
options.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
});
Define a default scheme in 2.0 if one of the following conditions is true:
You want the user to be automatically signed in
You use the [Authorize] attribute or authorization policies without specifying
schemes
An exception to this rule is the AddIdentity method. This method adds cookies for you and sets the default authenticate and challenge schemes to the application cookie IdentityConstants.ApplicationScheme. Additionally, it sets the default sign-in scheme to the external cookie IdentityConstants.ExternalScheme.
Hope this help you.
This is the source code of CookieAuthenticationEvents.OnRedirectToLogin :
public Func<RedirectContext<CookieAuthenticationOptions>, Task> OnRedirectToLogin { get; set; } = context =>
{
if (IsAjaxRequest(context.Request))
{
context.Response.Headers["Location"] = context.RedirectUri;
context.Response.StatusCode = 401;
}
else
{
context.Response.Redirect(context.RedirectUri);
}
return Task.CompletedTask;
};
You can add "X-Requested-With: XMLHttpRequest" Header to the request while making API calls from your client.
I found that in most cases the solution is to override
OnRedirectToLogin
But in my app I was using multiple authentication policies and overriding of the OnRedirectToLogin did not work for me. The solution in my case it was to add a simple middleware to redirect the incoming request.
app.Use(async (HttpContext context, Func<Task> next) => {
await next.Invoke(); //execute the request pipeline
if (context.Response.StatusCode == StatusCodes.Status302Found && context.Response.Headers.TryGetValue("Location", out var redirect)) {
var v = redirect.ToString();
if (v.StartsWith($"{context.Request.Scheme}://{context.Request.Host}/Account/Login")) {
context.Response.Headers["Location"] = $"{context.Request.Scheme}://{context.Request.Host}{context.Request.Path}";
context.Response.StatusCode = 401;
}
}
});
Another way to do this which is more DI/testing-friendly is to use AuthenticationSchemeOptions.EventsType (another answer points at it here). This will allow you to pull other components into the resolution process.
Here's an example including registration and resolution which stops the default redirect to login on an unauthenticated request, and instead just returns with a hard 401. It also has a slot for any other dependencies which may need to know about unauthenticated requests.
In Startup.cs:
services
.AddAuthentication("MyAuthScheme")
.AddCookie(CookieAuthenticationDefaults.AuthenticationScheme, options =>
{
options.EventsType = typeof(MyEventsWrapper);
};
...
services.AddTransient<MyEventsWrapper>();
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
Then, in MyEventsWrapper.cs:
public class MyEventsWrapper : CookieAuthenticationEvents
{
private readonly IHttpContextAccessor _accessor;
private readonly IDependency _otherDependency;
public MyEventsWrapper(IHttpContextAccessor accessor,
IDependency otherDependency)
{
_accessor = accessor;
_otherDependency = otherDependency;
}
public override async Task RedirectToLogin(RedirectContext<CookieAuthenticationOptions> context)
{
context.Response.Headers.Remove("Location");
context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
await _otherDependency.Cleanup(_accessor.HttpContext);
}
}
I'm not sure how to generate the 401 error, however if you use the:
o.AccessDeniedPath = "{path to invalid}";
This will allow you to redirect somewhere when the challenge has failed.

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