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WebServices/src/IdentitySvc/Pages/SecurityHeadersAttribute.cs

56 lines
2.5 KiB

// Copyright (c) Duende Software. All rights reserved.
// See LICENSE in the project root for license information.
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.AspNetCore.Mvc.RazorPages;
namespace IdentitySvc.Pages;
public sealed class SecurityHeadersAttribute : ActionFilterAttribute
{
public override void OnResultExecuting(ResultExecutingContext context)
{
ArgumentNullException.ThrowIfNull(context, nameof(context));
var result = context.Result;
if (result is PageResult)
{
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options
if (!context.HttpContext.Response.Headers.ContainsKey("X-Content-Type-Options"))
{
context.HttpContext.Response.Headers.Append("X-Content-Type-Options", "nosniff");
}
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options
if (!context.HttpContext.Response.Headers.ContainsKey("X-Frame-Options"))
{
context.HttpContext.Response.Headers.Append("X-Frame-Options", "DENY");
}
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
var csp = "default-src 'self'; object-src 'none'; frame-ancestors 'none'; sandbox allow-forms allow-same-origin allow-scripts; base-uri 'self';";
// also consider adding upgrade-insecure-requests once you have HTTPS in place for production
//csp += "upgrade-insecure-requests;";
// also an example if you need client images to be displayed from twitter
// csp += "img-src 'self' https://pbs.twimg.com;";
// once for standards compliant browsers
if (!context.HttpContext.Response.Headers.ContainsKey("Content-Security-Policy"))
{
context.HttpContext.Response.Headers.Append("Content-Security-Policy", csp);
}
// and once again for IE
if (!context.HttpContext.Response.Headers.ContainsKey("X-Content-Security-Policy"))
{
context.HttpContext.Response.Headers.Append("X-Content-Security-Policy", csp);
}
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referrer-Policy
var referrer_policy = "no-referrer";
if (!context.HttpContext.Response.Headers.ContainsKey("Referrer-Policy"))
{
context.HttpContext.Response.Headers.Append("Referrer-Policy", referrer_policy);
}
}
}
}