Utilize JWTBearer from multiple Identity Providers in ServiceStack API - servicestack

Question

Is it possible for a ServiceStack api to accept jwt tokens from multiple identity providers?
I have one admin application that will be calling all our apis across environments. I need to allow my api's to accept jwt tokens from two different identity providers. This can be accomplished in web api, by calling the .AddJwtBearer help method twice and not providing a default schema in the AddAuthentication() helper. And the providing both in the AddAuthorization helper method. I tested this out in ServiceStack and it is not working for me.
This is in the .net core startup, configure services.
services.AddAuthentication()
.AddJwtBearer("Bearer", options => {
options.Authority = Configuration["IDENTITYSRV_WEB_BASEURL"];
options.RequireHttpsMetadata = Boolean.Parse(Configuration["IDENTITY_HTTPSMETADATA"]);
options.Audience = Configuration["IDENTITY_VALIDAUDIENCE"];
})
.AddJwtBearer("Admin", options =>
{
options.Authority = "Configuration["IDENTITYSRV_WEB2_BASEURL"]";
options.RequireHttpsMetadata = Boolean.Parse(Configuration["IDENTITY_HTTPSMETADATA"]);
options.Audience = Configuration["IDENTITY_VALIDAUDIENCE"];
});
AppHost
AuthFeature auth = new AuthFeature(() => new AuthUserSession(), new IAuthProvider[] { new NetCoreIdentityAuthProvider(AppSettings), })
{
IncludeAssignRoleServices = false,
IncludeRegistrationService = false,
IncludeAuthMetadataProvider = false
};
Plugins.Add(auth);
Any suggestions or work around?

Answer 1

ServiceStack's JWT Auth Provider supports all HMAC and RSA crypto algorithms for its JWT or JWE tokens, but it can only be configured with the 1 algorithm you want it to use. So it's technically not possible for it to verify JWT Tokens from different authorities which would likely be configured with different keys and algorithms.
The next obstacle is that if all Identity providers were configured to use the same Key and Algorithm, they would need to encode the same contents ServiceStack uses in order for the JWT to be correctly deserialized into an Authenticated ServiceStack Session. Most of the names used in ServiceStack's JWT's have well-known names however there are others that don't like roles and perms, in which case ServiceStack JWT's have adopted the Azure Active Directory Conventions. Although there is an opportunity to apply custom logic when inspecting the verified JWT Body and populating the Session using the PopulateSessionFilter.
Ultimately I don't think trying to funnel multiple JWT's into the same implementation is a viable strategy, instead I would be looking at creating Custom JWT Auth Providers like JwtAuthProviderReader.cs which just knows how to handle parsing JWT's from a single provider which would then know how to verify & extract the Authenticated Session Info from each JWT and use it to populate a ServiceStack Session. This could be done in a "single uber JWT Auth Provider" that has knowledge in being able to parse every JWT sent to it, but as JWT Tokens are sent with the same Authorization: Bearer {Token} HTTP Header there would need to be some information in the JWT Headers that determines which crypto algorithms it should use to validate each token. If all Identity Providers use different alg then that might be enough to be able to distinguish the identity provider.
Either way there's no pre-built solution in ServiceStack that you could configure to support multiple identity Auth Providers, the other approach you may want to look at is to maintain all Authentication in a central Identity Server Auth Provider so then your Websites only need to be configured to support Authentication from the central Identity Server.