Medidata.MAuth

Medidata.MAuth is a framework that provides support for authenticating web services and applications with the Medidata HMAC protocol, MAuth.

Build Status

Build	Status
AppVeyor Release
AppVeyor Prerelease

What is MAuth?

The MAuth protocol provides a fault-tolerant, service-to-service authentication scheme for Medidata and third-party applications that use web services to communicate. The Authentication Service and integrity algorithm is based on digital signatures encrypted and decrypted with a private/public key pair.

The Authentication Service has two responsibilities. It provides message integrity and provenance validation by verifying a message sender's signature; its other task is to manage public keys. Each public key is associated with an application and is used to authenticate message signatures. The private key corresponding to the public key in the Authentication Service is stored by the application making a signed request; the request is encrypted with this private key. The Authentication Service has no knowledge of the application's private key, only its public key.

Medidata.MAuth Components

The framework is divided into separate semi-dependent NuGet packages to provide only the functionality which you need in your application. Below you can find the description of each individual packages.

Medidata.MAuth.Core

A core package for the MAuth protocol. This package contains the core functionality which used by the other MAuth authentication protocol-specific components. This package also can be used standalone if you want to sign HTTP/HTTPS requests with Medidata MAuth keys using the .NET HttpClient message handler mechanism.

The package recommended in client applications where the application is required to issue MAuth-signed requests to an MAuth-enabled service.

Medidata.MAuth.Owin

This package contains an OWIN middleware to validate signed HTTP requests with the Medidata MAuth protocol. The middleware communicates with an MAuth server in order to confirm the validity of the request authentication header.

Include this package in your OWIN-enabled application if you want to authenticate the incoming requests signed with the MAuth protocol.

Medidata.MAuth.AspNetCore

Similar to the Owin package this package has the ASP.NET Core-specific middleware that validates signed HTTP requests incoming to the application.

You can add this package in your ASP.NET Core web api application if you would like to authenticate your incoming requests signed with the MAuth protocol.

Medidata.MAuth.WebApi

The package contains an HTTP message handler to validate signed HTTP requests with the Medidata MAuth protocol. The handler communicates with an MAuth server in order to confirm the validity of the request authentication header.

Include this package in your WebAPI application if you want to authenticate the incoming requests signed with the MAuth protocol.

Get Started

Below you can find some information and examples on getting started using the framework.

Installation

Depending on your needs you can install either the Core package only (for signing requests), or the Owin or WebApi packages as well if you want to authenticate incoming requests.

The installation is as usual with NuGet.

For signing:

nuget install Medidata.MAuth.Core

Or in case of the authenticating, either

nuget install Medidata.MAuth.Owin

nuget install Medidata.MAuth.WebApi

For all of these you can use the Visual Studio Package Manager as well.

The Owin, AspNetCore and WebApi packages are dependent on the Core package, therefore it will be installed automatically in those cases.

Signing Outgoing Requests

In order to sign outgoing requests, an MAuthSigningHandler class is provided in the Core package. This handler accepts an MAuthSigningOptions instance which stores all the necessary settings for the signing process.

An example:

using Medidata.MAuth.Core;

public async Task<HttpResponseMessage> SignAndSendRequest(HttpRequestMessage request)
{
    var signingHandler = new MAuthSigningHandler(new MAuthSigningOptions()
    {
        ApplicationUuid = new Guid("7c872d75-986b-4c61-bb17-f2569d42bfb0"),

        // The following can be either a path to the key file or the contents of the file itself
        PrivateKey = "ClientPrivateKey.pem"
    });

    using (var client = new HttpClient(signingHandler))
    {
        return await client.SendAsync(request);
    }
}

The example above is creating a new instance of a HttpClient with the handler responsible for signing the requests and sends the request to its designation. Finally it returns the response from the remote server.

The MAuthSigningOptions has the following properties to determine the required settings:

Name	Description
ApplicationUuid	Determines the unique identifier of the client application used for the MAuth service authentication requests. This uuid needs to be registered with the MAuth Server in order for the authenticating server application to be able to authenticate the signed request.
PrivateKey	Determines the RSA private key of the client for signing a request. This key must be in a PEM ASN.1 format. The value of this property can be set as a valid path to a readable key file as well.

Authenticating Incoming Requests with the OWIN and ASP.NET Core Middlewares

If your application implements the OWIN-specific or ASP.NET Core pipeline, you can wire in the MAuthMiddleware provided by the Owin and AspNetCore NuGet packages.

The setting and usage is as follows in case of OWIN (in the application's Startup class):

using Medidata.MAuth.Owin;

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        app.UseMAuthAuthentication(options =>
        {
            options.ApplicationUuid = new Guid("a419de8f-d759-4db9-b9a7-c2cd14174987");
            options.MAuthServiceUrl = new Uri("https://mauth.imedidata.com");
            options.AuthenticateRequestTimeoutSeconds = 3;
            options.MAuthServiceRetryPolicy = MAuthServiceRetryPolicy.RetryOnce;
            options.HideExceptionsAndReturnUnauthorized = true;
            options.PrivateKey = "ServerPrivateKey.pem";
            options.Bypass = (request) => request.Uri.AbsolutePath.StartsWith("/allowed");
        });
    }
}

A similar way can be implemented for ASP.NET Core (also in the Startup class):

using Medidata.MAuth.AspNetCore;

public class Startup
{
    public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
    {
        app.UseMAuthAuthentication(options =>
        {
            options.ApplicationUuid = new Guid("a419de8f-d759-4db9-b9a7-c2cd14174987");
            options.MAuthServiceUrl = new Uri("https://mauth.imedidata.com");
            options.AuthenticateRequestTimeoutSeconds = 3;
            options.MAuthServiceRetryPolicy = MAuthServiceRetryPolicy.RetryOnce;
            options.HideExceptionsAndReturnUnauthorized = true;
            options.PrivateKey = "ServerPrivateKey.pem";
            options.Bypass = (request) => request.Uri.AbsolutePath.StartsWith("/allowed");
        });
    }
}

The middlewares take an MAuthMiddlewareOptions instance to set up the authentication:

Name	Description
ApplicationUuid	Determines the unique identifier of the server application used for the MAuth service authentication requests. This uuid needs to be registered with the MAuth Server in order to use it.
MAuthServiceUrl	Determines the endpoint of the MAuth authentication service. This endpoint is used by the authentication process to verify the validity of the signed request.
PrivateKey	Determines the RSA private key of the server application for the authentication requests. This key must be in a PEM ASN.1 format. The value of this property can be set as a valid path to a readable key file as well.
AuthenticateRequestTimeoutSeconds	An optional parameter that determines the timeout in seconds for the MAuth authentication request - the MAuth component will try to reach the MAuth server for this duration before it throws an exception. If not specified, the default value will be 3 seconds.
MAuthServiceRetryPolicy	The policy for the retry attempts when communicating with the MAuth service. The following policies can be used: `NoRetry` (no retries), `RetryOnce` (one additional attempt), `RetryTwice` (two additional attempts) and `Agressive` (9 additional attempts) - the default value is RetryOnce.
HideExceptionsAndReturnUnauthorized	An optional parameter that determines if the middleware should swallow all exceptions and return an empty HTTP response with a status code Unauthorized (401) in case of any errors (including authentication and validation errors). The default is true.
Bypass	Determines a function which evaluates if a given request should bypass the MAuth authentication.

The HideExceptionsAndReturnUnauthorized parameter is useful (if set to false) when you have an exception handler mechanism (for example a logger) in your middleware pipeline. In this case the MAuth middleware won't swallow the exceptions but will throw them with full stack trace and details of the problem - as every authentication errors will throw a Medidata.MAuth.Core.AuthenticationException you can still return a Unauthorized (401) HTTP status code in those cases. In the other hand, if you don't use any exception handling mechanism, it is recommended to leave this feature disabled as setting this to false can possibly lead to exposing sensitive details about your application and the authentication process. Leaving this parameter as true will result the middleware to return a Unauthorized (401) HTTP status code for every error without showing any details.

The Bypass function takes a IOwinRequest in case of OWIN and an HttpRequest instance for ASP.NET Core and should produce true as a result, if the given request satisfies the conditions to bypass the authentication; otherwise it should result false therefore an authentication attempt will occur. If no Bypass predicate provided in the options, every request will be authenticated by default.

Authenticating Incoming Requests with the WebApi Message Handler

If your application does not use the OWIN or ASP.NET Core middleware infrastructure, but it uses the ASP.NET WebAPI framework, the WebApi package provides an MAuthAuthenticatingHandler which can be assigned to WebAPI routes or the global handler collection in order to automatically authenticate incoming requests.

For a global registration (that is, use MAuth authentication for all requests), you can register the handler as below (in your WebApiConfig class):

using Medidata.MAuth.WebApi;

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        var options = new MAuthWebApiOptions()
        {
            ApplicationUuid = new Guid("a419de8f-d759-4db9-b9a7-c2cd14174987"),
            MAuthServiceUrl = new Uri("https://mauth.imedidata.com"),
            AuthenticateRequestTimeoutSeconds = 3,
            MAuthServiceRetryPolicy = MAuthServiceRetryPolicy.RetryOnce,
            HideExceptionsAndReturnUnauthorized = true,
            PrivateKey = "ServerPrivateKey.pem"
        };

        config.MessageHandlers.Add(new MAuthAuthenticatingHandler(options));
    }
}

Alternatively, you can add the authenticating handler to a specific route when you define the route:

using Medidata.MAuth.WebApi;

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        var options = // See the previous example

        config.Routes.MapHttpRoute(
            name: "Route1",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional },
            constraints: null,
            handler: new MAuthAuthenticatingHandler(options)
        );
    }
}

In the examples above, the MAuthWebApiOptions instance has the same properties as the OWIN- and ASP.NET Core-specific MAuthMiddlewareOptions.

Frequently Asked Questions

What are the license terms for Medidata.MAuth?

The framework is licensed under the MIT licensing terms.

What is the current target .NET Framework version?

The current target is .NET Framework 4.5.2 - this means that you have to use at least this target framework version in your project in order to make Medidata.MAuth work for you.

Is there an .NET Standard/Core support?

Yes, for signing outgoing requests you can use the library with any framework which implements the .NET Standard 1.4 and onwards; additionally we support the ASP.NET Core App 1.1 and onwards with a middleware for authenticating the incoming requests.

What Cryptographic provider is used for the encryption/decryption?

On the .NET Framework side (WebAPI, Owin, Core) we are using the latest version (as of date 1.81) of the BouncyCastle library; on the .NET Standard side (Core, AspNetCore) we are using the portable fork of the BouncyCastle library.

What are the major changes in the 2.0.0 version?

In this version we have only one major and a minor change: from this version the MAuthSigningHandler is accepting an MAuthSigningOptions instance instead of an MAuthOptions instance (which in turn set to be an abstract class). This change was necessary because the MAuthOptions object contains the MAuthServiceUrl property, which is not required for signing, but it had to be set to a valid Url nonetheless.

The other underlying change is that in the OWIN middleware the infrastructure provided request body stream gets replaced with a MemoryStream in cases when the original body stream is not seekable. This change was necessary, because in order to authenticate the request we need to read the body, but if the body stream is not seekable we are not able to restore it for the subsequent middlewares to read. Typical example for this is when the OWIN selfhost infrastructure is used as it wraps the original stream in a non-seekable version.

Does Medidata.MAuth support caching?

Yes, with the .NET Framework we support caching of the responses from the MAuth server in order to not overload it with client information requests. The caching mechanism in Medidata.MAuth is based on the WebRequestHandler's caching (with the request caching policy set to Default level), that utilizes the Windows OS built-in WinINET caching, thus it respects all the HTTP-specific cache headers provided by the MAuth server.

The documentation for the `MAuthServiceRetryPolicy.Agressive` retry policy says that it is not recommended for production use. What is the reason for this?

This policy will make the number of requests to the MAuth service to an overall 10 attempts. We believe that the chance to receive a successful response from the MAuth service is gradually decreasing by the number of attempts (the more the clients are sending requests to a presumably overloaded server the less the chance for a successful response) - therefore we do not recommend to use this policy in any production scenario.

johnduhart/mauth-client-dotnet