Add acr_values support for OIDC

[dirien]

Overview

What this PR does / why we need it

This PR adds acr_values support for the OIDC connection
Fixes: #2417

Special notes for your reviewer

Does this PR introduce a user-facing change?

yes, a new non-mandatory field is introduced called acrValues in the config of the OIDC connection

[dirien]

Created a PR for the website too -> dexidp/website#110

looking for your feedback!

[nabokihms]

Hello there! First of all, thank you for the PR. I have a couple of suggestions. Please look through the, when you have time.

1. Because RFC states that

   act_values is a space-separated string that specifies the acr values

   Let's use the same structure for the acrValues config option for scopes - a slice of strings.

2. In the Open method of the connector, compose the values of the slice into a single string.

3. What do you think about validating the acr_values_supported received from the discovery OIDC enpoint before sending a request or event on connector creation? Does it seem to be a good feature, or is it just a complication without benefits?

[dirien]

Hi @nabokihms,

thanks for the feedback! I changed your suggestions in the code.

What do you think about validating the acr_values_supported received from the discovery OIDC enpoint before sending a request or event on connector creation? Does it seem to be a good feature, or is it just a complication without benefits?

I would create for this, if needed in the future a seperate issue. Our company well-known/openid-configuration does not return acr_values_supported. So I can't test it proberly.

Looking for your feedback.

[dirien]

I updated the website too, as we have now a list instead a string

dexidp/website#110