Kentor.AuthServices 0.18.1 Breaking Changes

Today we released Kentor.AuthServices 0.18.1. It contains a number of bug fixes, but also a couple of breaking changes to a mostly internal API and logout handling.

You are affected if…

  • you build a HttpRequestData yourself, instead of using a build in ToHttpRequestData() extension method.
  • you are using Single Logout and…
    • you have a ClaimsAuthenticationManager
    • you manually create a AuthServicesClaimTypes.LogoutNameIdentifier claim
    • you filter out claims that are persisted

Most users should not be affected, but if you match any of the above please read on.

TLS on Azure with Legacy Android

In a recent project using Azure, SSL worked perfectly on all devices – but those running Android 2.X. It turned out that legacy Android has limited support for modern SSL/TLS features such as SNI and subject alternative name.

2015-09-08 09_08_05-WebmailGetting TLS configuration right nowadays can be quite tricky. Google Chrome is aggressively pushing for deprecation of old insecure standards by showing warnings or even errors on sites using deprecated https settings. Using a certificate issued merely two years ago, with the standards where common then now shows an error because the SHA-1 algorithm is not considered to be safe for the two remaining years of the lifetime of the certificate. The Google Chrome team is definitely pushing hard for moving web cryptography to safer grounds.

On the other end of the scale (no, I won’t be complaining about Windows XP, it’s not that much of a problem any more) is another Google product: Android. Even with the blazingly fast technology development, people are (IMHO rightfully) expecting a multi €100-device to last for more than a few years. That means that a lot of devices out there are still running Android 2.X. In this particular project, the target audience are not that tech-savvy. A lot of the users even have had to invest in their first smart phone, making their call-and-sms-only phones to history. With that audience, we had to support those old devices. On the other hand SSL warnings or errors in Chrome was unacceptable, so we had to find something that worked for all those platforms – and we did. Oh and by the way, the budget was really, really tight, so we had to find something that wasn’t too expensive.

Secure Account Activation with ASP.NET Identity

Distribution of credentials to new users of a system is often done in an insecure way, with passwords being sent over unsecure e-mail. With ASP.NET Identity, the password recovery functionality can be used to create a secure account activation mechanism.

The scenario for ASP.NET Identity, in the default MVC template is to let users self register. Then there are mechanisms to confirm the e-mail address, to make sure that the user actually is in control of the given e-mail address. There are also support for letting the user associate the account with external sign on solutions such as Google, Facebook and Twitter. That’s perfectly fine, but not for most applications I build.

I’m building line of business applications. They are actually often exposed on the Internet as they need to be available for partners. But, they are not meant to be available through self registration for anyone on the Internet. Those applications are invite only. That means that a user account is created for a new user. Then that user somehow has to be notified that the account has been created. The usual way to do that is to create the account, set a good password like “ChangeMe123” and send the user a mail with the new credentials. There are two problems with this

  1. A lot of users don’t get the hint and keep the “ChangeMe123” password.
  2. The e-mail can be sitting unread for a long time in the inbox, until someone gets hold of it – and the account.

Fortunately, there is a much more secure way to do account activation with ASP.NET Identity without much coding at all – by reusing the password recovery mechanism.

Pickup Mail Viewer

This is a guest post by Albin Sunnanbo introducing a great hack to work with mails in test environments.

If you have a .NET application that sends emails, this is probably something for you.

TL;DR;

PickupMailViewer is a simple web viewer for emails saved by the specifiedPickupDirectory SMTP setting in a .NET application.
Download the source, publish to your test server, configure pickup directory and you should be up and running within five minutes.

Outgoing Emails in Test Environments

In your test environment will typically not send real emails, but rather use the specifiedPickupDirectory delivery method for your SMTP-settings in web.config. This puts all outgoing emails as *.eml files in the file system instead of sending real emails.

IMHO that is the way to go regarding emails in your test environment.

However, there is one drawback, the emails gets dropped in a folder somewhere on your test server. Typically in a location that nobody looks at regularly. In my case I first have to connect a VPN, then open a remote desktop connection to our server, open the folder and copy the desired file back to my own computer (no eml viewer, a.k.a. Outlook, on the test server) and finally open it in Outlook.
Even worse for our testers that don’t even have permissions to login on the test machine. They have to ask a developer to get their emails out of the test system. As you can imagine this only happens when it is absolutely necessary.

Catching the System.Web/Owin Cookie Monster

CookieMonster-SittingCookies set through the Owin API sometimes mysteriously disappear. The problem is that deep within System.Web, there has been a cookie monster sleeping since the dawn of time (well, at least since .NET and System.Web was released). The monster has been sleeping for all this time, but now, with the new times arriving with Owin, the monster is awake. Being starved from the long sleep, it eats cookies set through the Owin API for breakfast. Even if the cookies are properly set, they are eaten by the monster before the Set-Cookie headers are sent out to the client browser. This typically results in heisenbugs affecting sign in and sign out functionality.

TL;DR

The problem is that System.Web has its own master source of cookie information and that isn’t the Set-Cookie header. Owin only knows about the Set-Cookie header. A workaround is to make sure that any cookies set by Owin are also set in the HttpContext.Current.Response.Cookies collection.

This is exactly what my Kentor.OwinCookieSaver middleware does. It should be added in to the Owin pipeline (typically in Startup.Auth.cs), before any middleware that handles cookies.

app.UseKentorOwinCookieSaver();

The cookie saver middleware preserves cookies set by other middleware. Unfortunately it is not reliable for cookies set by the application code (such as in MVC Actions). The reason is that the System.Web cookie handling code might be run after the application code, but before the middleware. For cookies set by the application code, the workaround by storing a dummy value in the sessions is more safe.

Software Development is a Job – Coding is a Passion

I'm Anders Abel, a systems architect and developer working for Kentor in Stockholm, Sweden.

profile for Anders Abel at Stack Overflow, Q&A for professional and enthusiast programmers

Code for most posts is available on my GitHub account.

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