I can't get email or profile scopes for an Azure B2C application, nor can I call the OIDC UserInfo endpoint - azure

Question

I'm finding Azure B2C really confusing. Currently I am using oauth2_proxy behind an nginx ingress controller in a test (single node) AKS kubernetes environment. I have made a slight change to oauth2_proxy to redirect upon error to chain Workflows together (like password recovery link etc.) and everything is working so far. I get an authorisation cookie from oath2_proxy and the ingress controller lets me through.
My next step is to work out what the username is, and maybe gather some more informaton. I think I can get some of the information in the id_token, but I am failing to see "email" and "preferred_username". Apparently these are only available if my token has the "email" and "profile" scopes, but I cannot work out how to get those scopes on my B2C App.
Currently I have a test application. In it's API permissions area I have a single "read" permission so that I have a resource to request to get an access_token. I also have "email", "offline_access", "openid", "profile" and "User.Read" permissions from "Microsoft Graph" - all permissions are granted by the admin on the API permissions screen.
The process I have been following up to now for testing is to run a signin workflow, selecting my API in the resources dropdown. I then copy the "Code" into a token request in postman, and then try both the "https://graph.microsoft.com/v1.0/me" and the "https://graph.microsoft.com/oidc/userinfo" endpoints with both the "id_token" and the "access_token". Both of these respond with "InvalidAuthenticationToken", message "Access token validation failure".
I had since noticed that my resources dropdown still only contains "read" and "openid" access rights, so I have been copying the "run userflow" url and inserting the scopes for "email", "offline_access", "openid" and "profile". I have also ensured that my call to the "token" endpoint contains these scopes. The response from the token endpoint only returns scopes "read offline_access openid", so "profile" and "email" are missing.
I don't know how to configure my app registration in B2C so that the "email" and "profile" scopes become available. Since "openid" appears in the resource drop down, I would expect "email" and "profile to turn up in there, but they don't. My token calls definitely show that the scopes that I need are not returned.
My workflow url looks as follows:
https://********.b2clogin.com/********.onmicrosoft.com/oauth2/v2.0/authorize?p=B2C_1_signup_signin&client_id=********&nonce=defaultNonce&redirect_uri=https%3A%2F%2Fjwt.ms&scope=openid%20user.read%20email%20profile%20offline_access%20https%3A%2F%2F********.onmicrosoft.com%2Ftestapp%2Fread&response_type=code&prompt=login
My token call looks as follows (using the code value from the workflow):
https://********.b2clogin.com/********/b2c_1_signup_signin/oauth2/v2.0/token?grant_type=authorization_code&client_id=********&response_type=code&redirect_uri=https://jwt.ms&response_mode=query&scope=https://********.onmicrosoft.com/apptest/read openid offline_access email profile&code=******CODE FROM WORKFLOW CALLBACK******
Token response is like:
{
"access_token": "******BIG LONG BASE64******",
"id_token": "******BIG LONG BASE64******",
"token_type": "Bearer",
"not_before": 1591607270,
"expires_in": 3600,
"expires_on": 1591610870,
"resource": "********",
"id_token_expires_in": 3600,
"profile_info": "******BASE64******",
"scope": "https://********.onmicrosoft.com/testapp/read offline_access openid",
"refresh_token": "******BASE64******",
"refresh_token_expires_in": 1209600
}
OIDC endpoint call like this:
https://graph.microsoft.com/oidc/userinfo
HAS HEADERS
Content-Type: application/json
Authorization: Bearer ********BASE64 from access_token********
Any help would be appreciated. i.e. how do I return additional scopes + how do I call the OIDC UserInfo endpoint.
Thanks.

Answer 1

I struggled with a similar issue a while back, where I wanted my API to use the access token to look up user info. Azure AD does not work in a standards compliant way:
Calling User Info requires a separate graph token
You have to use a token exchange request to get the graph token
Here are some resources of mine which I think are related and will hopefully give you enough info to resolve your problem. I think right now you are getting the error from Step 14 of the blog post.
Token Exchange + User Info Lookup C# Code
Blog Post on Azure AD Settings related to Graph / User Info