I'm trying to understand the proper way to do authentication in ASP.NET Core. I've looked at several Resource (Most of which are out dated).
Simple-Implementation-Of-Microsoft-Identity
Introduction to Authentication with ASP.Core
MSDNs Introduction to Identity
Some people provide altenative solutions stating to use a cloud based solution such as Azure AD, or to Use IdentityServer4 and host my own Token Server.
In Older version Of .Net one of the simpler forms of authentication would be to create an Custom Iprinciple and store additional authentication user data inside.
public interface ICustomPrincipal : System.Security.Principal.IPrincipal
{
string FirstName { get; set; }
string LastName { get; set; }
}
public class CustomPrincipal : ICustomPrincipal
{
public IIdentity Identity { get; private set; }
public CustomPrincipal(string username)
{
this.Identity = new GenericIdentity(username);
}
public bool IsInRole(string role)
{
return Identity != null && Identity.IsAuthenticated &&
!string.IsNullOrWhiteSpace(role) && Roles.IsUserInRole(Identity.Name, role);
}
public string FirstName { get; set; }
public string LastName { get; set; }
public string FullName { get { return FirstName + " " + LastName; } }
}
public class CustomPrincipalSerializedModel
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
}
Then you would Serialize your data into a cookie and return it back to the client.
public void CreateAuthenticationTicket(string username) {
var authUser = Repository.Find(u => u.Username == username);
CustomPrincipalSerializedModel serializeModel = new CustomPrincipalSerializedModel();
serializeModel.FirstName = authUser.FirstName;
serializeModel.LastName = authUser.LastName;
JavaScriptSerializer serializer = new JavaScriptSerializer();
string userData = serializer.Serialize(serializeModel);
FormsAuthenticationTicket authTicket = new FormsAuthenticationTicket(
1,username,DateTime.Now,DateTime.Now.AddHours(8),false,userData);
string encTicket = FormsAuthentication.Encrypt(authTicket);
HttpCookie faCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encTicket);
Response.Cookies.Add(faCookie);
}
My questions are:
How can I authenticate similar to the way done in previous version's of .Net does the old way still work or is there a newer version.
What are the pros and cons of using your own token server verses creating your own custom principle?
When using a cloud based solution or a separate Token server how would you Integrate that with your current application, would I would still need a users table in my application how would you associate the two?
Being that there are so many different solutions how can I create an enterprise application, to allow Login through Gmail/Facebook while still being able to expand to other SSO's
What are some simple implementations of these technologies?
TL;DR
IdentityServer = token encryption and validation services via OAuth 2.0/OpenId-Connect
ASP.NET Identity = current Identity Management strategy in ASP.NET
How can I authenticate similar to the way done in previous version's of .Net does the old way still work or is there a newer version.
I see no reason why you couldn't achieve the old way in ASP.NET Core, but in general, that strategy was replaced with ASP.NET Identity, and ASP.NET Identity is alive and well in ASP.NET Core.
https://learn.microsoft.com/en-us/aspnet/core/security/authentication/identity
ASP.NET Identity uses a backing store like SQL Server to hold user information like username, password (hashed), email, phone and easily be extended to hold FirstName, LastName or whatever else. So, there really no reason to encrypt user information into a cookie and pass it back and forth from client to server. It supports notions like user claims, user tokens, user roles, and external logins. Here are the entities in ASP.NET Identity:
AspNetUsers
AspNetUserRoles
AspNetUserClaims
AspNetUserLogins (for linking external identity providers, like Google, AAD)
AspNetUserTokens (for storing things like access_tokens and refresh_tokens amassed by the user)
What are the pros and cons of using your own token server verses creating your own custom principle?
A token server would be a system that generates a simple data structure containing Authorization and/or Authentication information. Authorization usually takes the for of a token named access_token. This would be the "keys to the house", so to speak, letting you through the doorway and into the residence of a protected resource, usually a web api. For Authentication, the id_token contains a unique identifier for a user/person. While it is common to put such an identifier in the access_token, there is now a dedicated protocol for doing that: OpenID-Connect.
The reason to have your own Security Token Service (STS), would to be to safeguard your information assets, via cryptography, and control which clients (applications) can access those resources. Furthermore, the standards for identity controls now exist in OpenID-Connect specifications. IdentityServer is an example of a OAuth 2.0 Authorization Server combined with an OpenID-Connect Authentication server.
But none of this is necessary if you just want a user table in your application. You don't need a token server- just use ASP.NET Identity. ASP.NET Identity maps your User to a ClaimsIdentity object on the server- no need for a custom IPrincipal class.
When using a cloud based solution or a separate Token server how would you Integrate that with your current application, would I would still need a users table in my application how would you associate the two?
See these tutorials for integrating separate identity solutions with an application:
https://identityserver4.readthedocs.io/en/latest/quickstarts/0_overview.html
https://auth0.com/docs/quickstart/webapp/aspnet-core
At a minimum you would need a two column table mapping the username to the external provider's user identifier. This is what the AspNetUserLogins table does in ASP.NET Identity. The rows in that table however are dependent on the being a User record in AspNetUsers.
ASP.NET Identity supports external providers like Google, Microsoft, Facebook, any OpenID-Connect provider, Azure AD are already there. (Google and Microsoft have already implemented the OpenID-Connect protocol so you don't need their custom integration packages either, like this one, for example). Also, ADFS is not yet available on ASP.NET Core Identity.
See this doc to get started with external providers in ASP.NET Identity:
https://learn.microsoft.com/en-us/aspnet/core/security/authentication/social/
Being that there are so many different solutions how can I create an enterprise application, to allow Login through Gmail/Facebook while still being able to expand to other SSO's
As explained above, ASP.NET Identity already does this. It's fairly easy to create an "External Providers" table and data drive your external login process. So when a new "SSO" comes along, just add a new row with the properties like the provider's url, the client id and secret they give you. ASP.NET Identity already has the UI built in there Visual Studio templates, but see Social Login for cooler buttons.
Summary
If you just need a users table with password sign in capabilities and a user profile, then ASP.NET Identity is perfect. No need to involve external authorities. But, if have many applications needing to access many apis, then an independent authority to secure and validate identity and access tokens makes sense. IdentityServer is a good fit, or see openiddict-core, or Auth0 for a cloud solution.
My apologies is this isn't hitting the mark or if it is too introductory. Please feel free to interact to get to the bulls-eye you are looking for.
Addendum: Cookie Authentication
To do bare bones authentication with cookies, follow these steps. But, to my knowledge a custom claims principal is not supported. To achieve the same effect, utilize the Claims list of the ClaimPrincipal object.
Create a new ASP.NET Core 1.1 Web Application in Visual Studio 2015/2017 choosing "No Authentication" in the dialog. Then add package:
Microsoft.AspNetCore.Authentication.Cookies
Under the Configure method in Startup.cs place this (before app.UseMvc):
app.UseCookieAuthentication(new CookieAuthenticationOptions
{
AuthenticationScheme = "MyCookieMiddlewareInstance",
LoginPath = new PathString("/Controller/Login/"),
AutomaticAuthenticate = true,
AutomaticChallenge = true
});
Then build a login ui and post the html Form to an Action Method like this:
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Login(String username, String password, String returnUrl = null)
{
ViewData["ReturnUrl"] = returnUrl;
if (ModelState.IsValid)
{
// check user's password hash in database
// retrieve user info
var claims = new List<Claim>
{
new Claim(ClaimTypes.Name, username),
new Claim("FirstName", "Alice"),
new Claim("LastName", "Smith")
};
var identity = new ClaimsIdentity(claims, "Password");
var principal = new ClaimsPrincipal(identity);
await HttpContext.Authentication.SignInAsync("MyCookieMiddlewareInstance", principal);
return RedirectToLocal(returnUrl);
}
ModelState.AddModelError(String.Empty, "Invalid login attempt.");
return View();
}
The HttpContext.User object should have your custom claims and are easily retrievable the List collection of the ClaimPrincipal.
I hope this suffices, as a full Solution/Project seems a bit much for a StackOverflow post.
TL;DR
I would really like to Show A Full posting on how to properly implement IdentityServer4 but I tried to fit All of the Text in but it was beyond the limit of what StackOverflow Accepts so instead I will right some tips and things I've learned.
What are the Benefits of using a Token Server Vs ASP Identity?
A token server, has a lot of benefit's but it isn't right for everyone. If you are implementing an enterprise like solution, where you want multiple client to be able to login, Token server is your best bet, but if you just making a simple website that want to support External Logins, You can get Away With ASP Identity and some Middleware.
Identity Server 4 Tips
Identity server 4 is pretty well documented compared to a lot of other frameworks I've seen but it's hard to start from scratch and see the whole picture.
My first mistak was trying to use OAuth as authentication, Yes, there are ways to do so but OAuth is for Authorization not authentication, if you want to Authenticate use OpenIdConnect (OIDC)
In my case I wanted to create A javascript client, who connects to a web api.
I looked at a lot of the solutions, but initially I tried to use the the webapi to call the Authenticate against Identity Server and was just going to have that token persist because it was verified against the server. That flow potentially can work but It has a lot of flaws.
Finally the proper flow when I found the Javascript Client sample I got the right flow. You Client logs in, and sets a token. Then you have your web api consume the OIdc Client, which will verify your access token against IdentityServer.
Connecting to Stores and Migrations
I had a lot of a few misconceptions with migrations at first. I was under the impression that running a migration Generated the SQL from the dll internally, instead of using you're configured Context to figure out how to create the SQL.
There are two syntaxes for Migrations knowing which one your computer uses is important:
dotnet ef migrations add InitialIdentityServerMigration -c ApplicationDbContext
Add-Migration InitialIdentityServerDbMigration -c ApplicationDbContext
I think the parameter after the Migration is the name, why you need a name I'm not sure, the ApplicationDbContext is a Code-First DbContext in which you want to create.
Migrations use some auto-magic to find you're Connection string from how your start up is configured, I just assumed it used a connection from the Server Explorer.
If you have multiple projects make sure you have the project with the ApplicationDbContext set as your start up.
There is a lot of moving parts when Implementing Authorization and Authentication, Hopefully, this post helps someone. The easiest way to full understand authentications is to pick apart their examples to piece everything together and make sure your read the documentation
ASP.NET Identity - this is the build in a way to authenticate your application whether it is Bearer or Basic Authentication, It gives us the readymade code to perform User registration, login, change the password and all.
Now consider we have 10 different applications and it is not feasible to do the same thing in all 10 apps. that very fragile and very bad practice.
to resolve this issue what we can able to do is centralize our Authentication and authorization so whenever any change with this will not affect all our 10 apps.
The identity server provides you the capability to do the same. we can create one sample web app which just used as Identity service and it will validate your user and provide s some JWT access token.
I have always used the built in ASP.NET Identity (and previously Membership) authorisation/authentication, I have implemented Auth0 recently (https://auth0.com) and recommend this as something else to try.
Social logins are not hard to implement with Identity, but there is some initial setup involved and sometimes the steps you find online in the docs are not identical, usually you can find help for that under the developers section of the platform you are trying to setup the social logins for. Identity is the replacement of the old membership functionality found in legacy versions of the .net framework.What I have found surprising is that edge use cases, like passing a jwt token you already have to a web api are not covered anywhere in the examples online even on pluralsight, I am sure you don't need your own token authority to do this but I have not found a single example on how to pass data in a get or post that isn't dealing with a self-hosted server.
I am using Integrated Windows Authentication in my application so domain users alone can access the application.
After this step, I am doing some additional authentication to check whether that domain user is permitted to access the application (domain user will be added in a database table).
To achieve this, I am doing in the following way. Is this the best practice?? Please advise.
public class CCUKAuthorizeAttribute : AuthorizeAttribute
{
protected override bool AuthorizeCore(HttpContextBase httpContext)
{
var isAuthorized = base.AuthorizeCore(httpContext);
var isUserAddedinDB = true; //Code to check whether user is added in DB
return isUserAddedinDB;
}
}
What you are trying to do is first check authentication and then check for an authorization rule(can he access application). I guess this is a onetime check which happens only during the first time authentication process. In that case you better separate that logic into a different method (Separation of Concerns).
Generally in a MVC application if you need to do a custom Authorization check, I would recommend to do Authorization check by overriding "Authorize" attribute (example).
I am working on my first ASP.Net MVC 4 application and now stuck with one simple use case.
I need to authenticate one single user (Admin) so that he/she can log in to admin area to perform certain tasks. Though the ASP.Net internet project template has Account controller using simple membership but that seems to have much more than what I actually need. For instance, I don't really need the user registration functionality and user roles. My requirements are fairly simple, just to store one single user in database, give him the options to update his info like password, email etc and grant him access to admin area (admin controller and actions).
What I can't figure out is
Are simple membership or other asp.net membership provider my only options for this simple scenario.
If not what other option do I have in order to use [Authorize] to secure admin actions
You can build a custom method to grab the user and their stored role, then evaluate it in your controller. So, for instance:
public ActionResult GetAdminPage()
{
var loggedInUserName = HttpContext.User.Identity.Name;
var user = somesortofproviderlookupmethod(loggedInUserName);
// Assume user is a bool and is true
if (user)
{
return view("AdminPage");
}
}
The only thing I'm not sure of is whether or not HttpContext.User requires membership. Perhaps someone can shed some light. If so, perhaps you could send the username from the view, but then of course you're trusting the client. So how you are doing user authentication would change this answer somewhat.
Personally, I like membership. It's clean, easy, fast and can be scaled nicely if you end up having additional requirements. Doing something like this would be even easier with membership, since then you can actually use Roles.GetRolesForUser(); and only return the admin view if they contain the role you are looking for.
I have a class library which contains my data base access layer, and i use it in all my projects which works with this DB, now i want to integrate security in this library so i can return different data for different security roles. What is the best way to achieve this with .NET build-in security?
I was thinking about using System.Security.Permissions.PrincipalPermission but i can't see how it can help me out, because anyone using my library can write client application like this
GenericIdentity genericIdentity = new GenericIdentity("User");
GenericPrincipal genericPrincipal = new GenericPrincipal(genericIdentity, new[] { "Administrator" });
Thread.CurrentPrincipal = genericPrincipal;
And they will pass all my principal permission demands
PrincipalPermission principalPermission = new PrincipalPermission(null, "Administrator");
principalPermission.Demand();
without even authenticating.
Either i don't understand this security model, or it just doesn't secure anything.
Role-based security is intended as a way for library code to consume the client's chosen security model without needing to know the implementation; the key here being that you are already at a point where it is reasonably to trust the client's security model, and you just want to offer appropriate options based on decisions made by the client (for example as part of a login process).
If you don't trust the client, all bets are off anyway, as they could just use reflection to rip your internals to shreds. In that scenario, it would be better to keep that implementation code private, for example via a web-service that accepts the user's credentials in some fashion. Then they can only be accounts that they have the credentials for.
public class Example
{
// Will enforce that the user have the administrator role
[PrincipalPermission(XXXX, Role="Administrator")]
public void Remove(int userId)
{
}
public void Add(int userId)
{
if (!Thread.CurrentPrincipal.IsInRole("User"))
throw new UnauthorizedAccessException("Only registered users may add users");
}
}
How the actual principal/identity configuration is setup is up to the user of your library.
I need to write a program used internally where different users will have different abilities within the program.
Rather than making users have a new username and password, how do I tie into an existing domain server's login system?
Assume .NET (C#, VB, ASP, etc)
-Adam
For WinForms, use System.Threading.Thread.CurrentPrincipal with the IsInRole() method to check which groups they are a member of. You do need to set the principal policy of the AppDomain to WindowsPrincipal first.
Use this to get the current user name:
private string getWindowsUsername()
{
AppDomain.CurrentDomain.SetPrincipalPolicy(PrincipalPolicy.WindowsPrincipal);
return Thread.CurrentPrincipal.Identity.Name;
}
And then something like this to check a role:
if (Thread.CurrentPrincipal.IsInRole("Domain Users") == true)
{}
In ASP.NET, the thread will belong to IIS, so instead you should
Set the virtual folder or website to require authentication
Get the user name supplied by the browser with Request.ServerVariables("LOGON_USER")
Use the DirectorySearcher class to find the users groups
I would use LDAP
and the DirectorySearcher Class:
http://msdn.microsoft.com/en-us/library/system.directoryservices.directorysearcher.aspx
Assuming this is served through IIS, I would tell IIS to authenticate via the domain, but I would keep authorization (what roles a user is associated with, accessible functionality, etc) within the application itself.
You can retreive the username used to authenticate via
Trim(Request.ServerVariables("LOGON_USER")).Replace("/", "\").Replace("'", "''")
OR
CStr(Session("User")).Substring(CStr(Session("User")).LastIndexOf("\") + 1)