Add auth-signin-snippet annotation

[omartin2342]

We use the annotations nginx.ingress.kubernetes.io/auth-signin and nginx.ingress.kubernetes.io/auth-url to authorize requests.

When an unauthenticated request is detected and nginx.ingress.kubernetes.io/auth-url is called we need the possibility to include our own nginx configuration in the nginx location and return something else than “just” the 301 to the URI in nginx.ingress.kubernetes.io/auth-signin.

A concrete use case is that we want a redirect to the nginx.ingress.kubernetes.io/auth-signin URL only when an HTML page is requested (e.g. HTTP header accept: text/html is present). If an API call is made, the status code 401 should be returned instead of a redirect.

---- 8< ---- set $do401 “”; if ($http_accept ~= “text/html” ) { set $do401 “${do401}1”; } if ($request_method = GET) { set $do401 “${do401}1”; } if ($do401 == “11”) { return 401; } ---- >8 ----

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] CVE Report (Scanner found CVE and adding report)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Documentation only

Which issue/s this PR fixes

None

How Has This Been Tested?

Test environment has been setup with a vanilla Kubernetes in our datacenter. Patched ingress-nginx and a deployment of our software with a ingress resource annotated with auth-url, auth-sigin and auth-signin-snippet have been deployed. Request with browser and api client have been made. All has been as before except that XHR requests with invalid token got an 401 response instead of the unwanted 301.

Checklist:

• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] I've read the CONTRIBUTION guide
• [x] I have added unit and/or e2e tests to cover my changes.
• [ ] All new and existing tests passed.
• [X] Added Release Notes.

Add new annotation nginx.ingress.kubernetes.io/auth-signin-snippet for External Auth

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[rikatz]

Snippets has been shown one of our biggest problems in security. I really don't want to merge any new thing with snippets, so from me is a -1 :(

Can we have whatever is needed via snippets as proper configurations/annotations? If not, I'm not willing to merge this, unless @tao12345666333 @strongjz have some different idea

[chriss-de]

Hi

I'm interested in this feature too.

Considering your question if we can have it as proper annotation and not as snippet - how would that work. there is use case specific logic in the snippet. I'm somewhat sure that if it would be an annotation (like auth-do401-if-browser) there would be a discussion on how to correctly detect a browser.

Could you hint on what you would be willing to merge that is close to what omartin2342 tries to achieve?

kind regards

[simhnna]

We took some time to think about our options to accomplish our goal of treating api requests and users differently.

We'd be able to do that in our default backend, if we manage to route the errors of external auth there. We actually think that there is a wider usecase to be able to do that and opened #9211 to discuss our approach there

[simhnna]

@rikatz what do you think about the proposal in #9221. That should cover the use case presented in this mr without using any snippets

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@omartin2342: PR needs rebase.

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[omartin2342]

Solved with #9411