Service Stack - Custom authentication on one route - authentication

Question

In my current application, I am using Service Stack with JWT's for security. Security has been implemented and works perfectly. Trouble is, I would like to secure one route differently from the others. There is a document the logged in user retrieves, I want to make sure the document they are retrieving is theirs and not someone else's. It is very sensitive data. I would like to secure it differently because something like PostMan could be used with a valid token to retrieve any document, I want to prevent this. The users id is in the token, I would like to match it against the document that is being retrieved if possible. The current security is implemented like so:
public class AppHost: AppHostBase
{
public override void Configure(Funq.Container container)
{
Plugins.Add(new AuthFeature(() => new AuthUserSession(),
new IAuthProvider[] {
new JsonWebTokenAuthProvider("myKey", "myAudience"),
}));
}
}
JsonWebTokenAuthProvider is a custom class where security was implemented, this all works perfectly. Here is the code:
public override object Authenticate(IServiceBase authService, IAuthSession session, Authenticate request)
{
// first validate the token, then get roles from session
string header = request.oauth_token;
// if no auth header, 401
if (string.IsNullOrEmpty(header))
{
throw HttpError.Unauthorized(MissingAuthHeader);
}
string[] headerData = header.Split(' ');
// if header is missing bearer portion, 401
if (!string.Equals(headerData[0], "BEARER", StringComparison.OrdinalIgnoreCase))
{
throw HttpError.Unauthorized(InvalidAuthHeader);
}
// swap - and _ with their Base64 string equivalents
string secret = SymmetricKey.Replace('-', '+').Replace('_', '/');
string token = headerData[1].Replace("\"", "");
// set current principal to the validated token principal
Thread.CurrentPrincipal = JsonWebToken.ValidateToken(token, secret, Audience, true, Issuer);
string lanId = GetLanID(Thread.CurrentPrincipal.Identity.Name);
string proxyAsLanId = request.Meta.ContainsKey(META_PROXYID) ? request.Meta[META_PROXYID] : null;
if (HttpContext.Current != null)
{
// set the current request's user the the decoded principal
HttpContext.Current.User = Thread.CurrentPrincipal;
}
// set the session's username to the logged in user
session.UserName = Thread.CurrentPrincipal.Identity.Name;
session.Roles = GetApplicableRoles(lanId, proxyAsLanId);
authService.Request.SetItem("lanID", lanId);
authService.Request.SetItem("proxyAsLanId", proxyAsLanId);
return OnAuthenticated(authService, session, null, null);
}
I looked up RequestFilterAttribute found here, but I do not think that is what I want. Ideally, if the check fails I would like to return a 401 (unauthorized) if possible.
What is the best way to do this?

Answer 1

If you just want to handle one route differently than you can just add the validation in your single Service, e.g:
public object Any(MyRequest dto)
{
var lanId = base.Request.GetItem("lanId");
if (!MyIsValid(lanId))
throw HttpError.Unauthorized("Custom Auth Validation failed");
}
You could do the same in a RequestFilter, e.g:
public class CustomAuthValidationAttribute : RequestFilterAttribute
{
public override void Execute(IRequest req, IResponse res, object responseDto)
{
var lanId = req.GetItem("lanId");
if (!MyIsValid(lanId))
{
res.StatusCode = (int) HttpStatusCode.Unauthorized;
res.StatusDescription = "Custom Auth Validation failed";
res.EndRequest();
}
}
}
And apply it to a single Service:
[CustomAuthValidation]
public object Any(MyRequest dto)
{
//...
}
Or a collection of Services, e.g:
[CustomAuthValidation]
public class MyAuthServices : Service
{
public object Any(MyRequest1 dto)
{
//...
}
public object Any(MyRequest2 dto)
{
//...
}
}