I am working with a permission based authorization system for my app in ASP.NET MVC. For this I have created a custom authorization attribute
public class MyAuthorizationAttribute : AuthorizeAttribute
{
string Roles {get; set;}
string Permission {get; set;}
}
so that I can authorize a user by both role or a specific permission key with annotation for actions like
public class UserController : Controller
{
[MyAuthorization(Roles="ADMIN", Permissions="USER_ADD")]
public ActionResult Add()
[MyAuthorization(Roles="ADMIN", Permissions="USER_EDIT")]
public ActionResult Edit()
[MyAuthorization(Roles="ADMIN", Permissions="USER_DELETE")]
public ActionResult Delete()
}
then I override AuthorizeCore() method in MyAuthorizationAttribute class with similar logic(pseudo code)
protected override bool AuthorizeCore(HttpContextBase httpContext)
{
if(user not authenticated)
return false;
if(user has any role of Roles)
return true;
if(user has any permission of Permissions)
return true;
return false;
}
Up to this is working fine.
Now I need some sort of extension methods so that I can dynamically generate action url in view pages that will return action url based on MyAuthorization attribute authorization logic for the given action. Like
@Url.MyAuthorizedAction("Add", "User")
will return url to "User/Add" if user has admin role or has permission of "USER_ADD" (as defined in attributes for the action) or return empty string otherwise.
But after searching in internet for few days I could not figure it out. :(
So far I have found only this "Security aware" action link? which works by executing all action filters for the action until it fails.
It's nice, but I think it would be an overhead to execute all the action filters for each time I call the MyAuthorizedAction() method. Besides It also didn't work with my version (MVC 4 and .NET 4.5)
What all I need is to check authenticated user's role, permissions (will be stored in session) against authorized role and permission for the given action. Like something as following (pseudo code)
MyAuthorizedAction(string actionName, string controllerName)
{
ActionObject action = SomeUnknownClass.getAction(actionName, controllerName)
MyAuthorizationAttribute attr = action.returnsAnnationAttributes()
if(user roles contains any in attr.Roles
or
user permissions contains any attr.Permissions)
{
return url to action
}
return empty string
}
I am searching the solution of getting action attributes value for quite a long time, could not find enough good resources at all. Am I missing out right keywords? :/
If anyone can provide me the solution that would be truly a great help. Thanks in advance for the solutions
While I agree that generating urls based on permissions is probably not best practices, if you want to continue anyway you can find the actions and their attributes using these:
Retrieve 'Action' methods: This retrieves a collection of method infos because it is possible to have multiple Controller classes with the same name and multiple methods of the same name in particular with the use of areas. If you have to worry about this I'll leave the disambiguation up to you.
Retrieve Permissions from MyAuthorizationAttributes:
Finally the AuthorizedAction extension: warning:If you do have more than one match for a given controller/action pair this will give the 'authorized' url if the user is authorized for any of them...
A Note on Generating Urls Based on Permissions:
I state this is probably not best practice because of many little things. Each may have their own level of relevance depending on your situation.
Controlling Page Rendering Via Action Authorization attributes: Modify the
AuthorizedAction
method to be aboolean
, then use the result of that to control page rendering.Then use this in your razor pages.
My only recommendation would be to write an extensions methods on
IPrincipal
instead which would look likeThen your code in the views/partials is a little more readable in terms of what it's actually doing (not doing anything with html, but validating a user) then the code in the views/partials looks like
Each MVC Page has the property WebViewPage.User for the current user.
The problem with your purposed solution (and the link to security aware link) is that the creation of the link, and the Authorize on the controllers could be different (and mixing responsibilities in this type of fashion in MY opinion is bad practice). By extending
IPrincipal
a new authorization would look like:Now both your Authorize Attribute and Views use the same roles/permissions data logic.
I don't think you should check the action annotations each time you want to create an url with Url.Action(). If the action is secured with custom authorization filter it won't be executed for unprivileged user, so what's the point in hiding URL to that action? Instead you could implement extension method on HtmlHelper to check if the current user has the given premission, like:
Then you could use the helper inside the views to hide buttons and links that are not accessible for the current user, like:
Of course this hiding of specific links is only for UI purposes - the real controll of access is done by the custom authorization attribute.