Unable to map Okta Groups Claim to Roles Claim in Blazor WASM Client

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Issue

I am trying to leverage the AuthorizeView component in Blazor to hide/show different parts of the page based on a users role. I am using OIDC connected to OKTA as the auth provider.

By default, OKTA return the Roles scope as a Groups claim within the id_token. I have attempted to force authentication provider to look at the groups claim for the roles as seen in the code below.

My test account has the appropriate permissions, as I can see it within the Groups claim. I am unable to get this mapping to work.

Has anyone had any similar issues and/or found a solution to this?

Sample Code

-- Program.cs --
public static async Task Main(string[] args)
{
    ...

    builder.Services.AddOidcAuthentication(options =>
    {
        options.ProviderOptions.Authority = "***";
        options.ProviderOptions.ClientId = "***";
        options.ProviderOptions.DefaultScopes.Add("roles");
        options.ProviderOptions.ResponseType = "token id_token";
        
        options.UserOptions.RoleClaim = "groups";
        options.UserOptions.NameClaim = "name";
    });

    ....
}

-- MyPage.razor --
<AuthorizeView Roles="Admin">
    <Authorized>
        Authorized
    </Authorized>
    <NotAuthorized>
        Not Authorized
    </NotAuthorized>
</AuthorizeView>
asp.net-core-3.1 blazor-webassembly okta blazor
1 Answers

Solution

I found the following article: http://blazorhelpwebsite.com/Blog/tabid/61/EntryId/4376/Implementing-Roles-In-Blazor-WebAssembly.aspx, which explains how to use a custom Claims Principal Factory.

I copied the code from the article and adjusted accordingly to my needs

RolesClaimsPrincipalFactory.cs

public class RolesClaimsPrincipalFactory : AccountClaimsPrincipalFactory<RemoteUserAccount>
{
    public RolesClaimsPrincipalFactory(IAccessTokenProviderAccessor accessor) : base(accessor)
    {
    }

    public override async ValueTask<ClaimsPrincipal> CreateUserAsync(
        RemoteUserAccount account, RemoteAuthenticationUserOptions options)
    {
        var user = await base.CreateUserAsync(account, options);
        if (!user.Identity.IsAuthenticated)
        {
            return user;
        }

        var identity = (ClaimsIdentity) user.Identity;
        var roleClaims = identity.FindAll(claim => claim.Type == "groups");
        if (roleClaims == null || !roleClaims.Any())
        {
            return user;
        }

        foreach (var existingClaim in roleClaims)
        {
            identity.RemoveClaim(existingClaim);
        }

        var rolesElem = account.AdditionalProperties["groups"];
        if (!(rolesElem is JsonElement roles))
        {
            return user;
        }

        if (roles.ValueKind == JsonValueKind.Array)
        {
            foreach (var role in roles.EnumerateArray())
            {
                identity.AddClaim(new Claim(options.RoleClaim, role.GetString()));
            }
        }
        else
        {
            identity.AddClaim(new Claim(options.RoleClaim, roles.GetString()));
        }

        return user;
    }
}

Program.cs

public class Program
{
    public static async Task Main(string[] args)
    {
        ...

        builder.Services.AddOidcAuthentication(options =>
        {
            options.ProviderOptions.Authority = ******;
            options.ProviderOptions.ClientId = ******;
            options.ProviderOptions.DefaultScopes.Add("roles");
            options.ProviderOptions.ResponseType = "token id_token";

            options.UserOptions.RoleClaim = "role";
        }).AddAccountClaimsPrincipalFactory<RolesClaimsPrincipalFactory>();

        ...
    }
}

Key Takeaways

  1. You are required to specify a RoleClaim options.UserOptions.RoleClaim = "role";. If you do not you will get a NullReferenceException.
  2. Implementing the custom claims principal is done by using the extension method AddAccountClaimsPrincipalFactory<T>().
  3. This solution seems like a niche case for OKTA Auth, Blazor WASM and OIDC.
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