Complex Claim Values in .NET Framework with System.Security.Claims

Question

I'm developing a web app with Asp.Net 5 MVC, Owin and Oauth2 bearer token as auth type.

Following this guide that adds a custom complex claim Json serialized to an instance of Microsoft.IdentityModel.Claims.ClaimsIdentity with success, I've tried to replicate the same example using the ClaimsIdentity on the System.Security.Claims namespace.

Unluckily, it seems that adding a complexClaim to the ClaimsIdentity instance, the derived class type information is lost, and the claim is stored as a System.Security.Claims.Claim.

var complexClaim = new ComplexClaim<UKPassport>(@"http://it.test/currentpassport", passport);
var claims = new List<Claim>() { complexClaim };
identity.AddClaims(claims);

When I try to get back the claim from identity, casting it to to a ComplexClaim<UKPassport> Type results in a null value.

var passportClaim = identity.Claims.FirstOrDefault<Claim>(c=>c.Type == @"http://it.test/currentpassport") as ComplexClaim<UKPassport>;

The same example works perfectly using Microsoft.IdentityModel.Claims.

Any hints?

Here is the complete ported code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json;
using System.Security.Claims;

namespace ConsoleApplication1
{
    class Program {
    private static ClaimsIdentity identity = new ClaimsIdentity();

    static void Main(string[] args)
    {
        var oldPassport = CreatePassport();
        identity.AddPassport(oldPassport);

        var britishCitizen = identity.IsBritishCitizen();
        var hasExpired = identity.IsCurrentPassportExpired();
        Console.WriteLine(hasExpired); 
        Console.ReadLine();
    }

    private static UKPassport CreatePassport()
    {
        var passport = new UKPassport(
            code: PassportCode.GBR, 
            number: 123456789,
            expiryDate: DateTime.Now);

        return passport;
    }
}

    public static class ClaimsIdentityExtensions {
    public static void AddPassport(this ClaimsIdentity identity, UKPassport passport)
    {
        var complexClaim = new ComplexClaim<UKPassport>(@"http://it.test/currentpassport", passport);

        var claims = new List<Claim>() { complexClaim };
        identity.AddClaims(claims);
    }

    public static bool IsCurrentPassportExpired(this ClaimsIdentity identity)
    {
        var passport = GetPassport(identity, @"http://it.test/currentpassport");
        return DateTime.Now > passport.ExpiryDate;
    }

    public static bool IsBritishCitizen(this ClaimsIdentity identity)
    {
        var passport = GetPassport(identity, @"http://it.test/currentpassport");
        return passport.Code == PassportCode.GBR;
    }

    private static UKPassport GetPassport(this ClaimsIdentity identity, string passportType)
    {
        var passportClaim = identity.Claims.FirstOrDefault<Claim>(c=>c.Type == @"http://it.test/currentpassport") as ComplexClaim<UKPassport>;
        return passportClaim.Value;
    }
}

    public enum PassportCode
    {
        GBR,

        GBD,

        GBO,

        GBS,

        GBP,

        GBN
    }


    public class ComplexClaim<T> : Claim where T : ClaimValue
    {
        public ComplexClaim(string claimType, T claimValue)
            : this(claimType, claimValue, string.Empty)
        {
        }

        public ComplexClaim(string claimType, T claimValue, string issuer)
            : this(claimType, claimValue, issuer, string.Empty)
        {
        }

        public ComplexClaim(string claimType, T claimValue, string issuer, string originalIssuer)
            : base(claimType, claimValue.ToString(), claimValue.ValueType(), issuer, originalIssuer)
        {
        }

        public new T Value
        {
            get
            {
                return JsonConvert.DeserializeObject<T>(base.Value);
            }
        }
    }

    public class UKPassport : ClaimValue
    {
        public const string Name = "UKPassport";

        private readonly PassportCode code;
        private readonly int number;
        private readonly DateTime expiryDate;

        public UKPassport(PassportCode code, int number, DateTime expiryDate)
        {
            this.code = code;
            this.number = number;
            this.expiryDate = expiryDate;
        }

        public PassportCode Code { get { return this.code; } }
        public int Number { get { return this.number; } }
        public DateTime ExpiryDate { get { return this.expiryDate; } }

        public override string ValueType()
        {
            return @"http://it.test/currentpassport";
        }
    }    

public abstract class ClaimValue {
    public abstract string ValueType();

    public override string ToString()
    {
        return JsonConvert.SerializeObject(this);
    }
}
}

leastprivilege leastprivilege · Accepted Answer · 2014-07-18T09:38:31

This is not supported nor recommended - claims are key / value pairs - keep them as simple as possible.

There are a number of supporting classes in .NET that can't handle what you are trying to achieve (the SAM, CookieMiddleware etc)..

see also here http://leastprivilege.com/2012/10/08/custom-claims-principals-in-net-4-5/

Complex Claim Values in .NET Framework with System.Security.Claims

2 Answers