wonderwall

Wonderwall is an application that implements an OpenID Connect (OIDC) relying party/client in a way that makes it easy to plug into Kubernetes applications as a sidecar.

As such, this is OIDC as a sidecar, or OaaS, or to explain the joke:

Oasis - Wonderwall

Wonderwall functions as a reverse proxy that should be placed in front of your application; intercepting and proxying requests. It provides endpoints to perform logins and logouts for end users, along with session management - so that your application does not have to.

Architecturally, Wonderwall is modeled after the backend-for-frontend (BFF) pattern as described in Best Current Practices - OAuth 2.0 for Browser-Based Apps, section 6.1.

Features

Wonderwall aims to be compliant with OAuth 2.1, and supports the following:

• OpenID Connect Authorization Code Flow with mandatory use of PKCE, state and nonce
• Client authentication using client assertions (private_key_jwt) (RFC 7523, Section 2.2)
• OpenID Connect RP-Initiated Logout
• OpenID Connect Front-Channel Logout
• OAuth 2.0 Pushed Authorization Requests (RFC 9126)
• Encrypted sessions with XChaCha20-Poly1305, stored using Redis as the backend
• Two deployment modes:
  • Standalone mode (default) for zero-trust based setups where each application has its own perimeter and client
  • Single sign-on (SSO) mode for shared authentication across multiple applications on a common domain

How it works

End-user authentication using Wonderwall is fairly straightforward:

• If the user does not have a valid local session with the sidecar, requests will be proxied to the upstream host as-is without modifications.
• To obtain a local session, the user must be redirected to the /oauth2/login endpoint, which will initiate the OpenID Connect Authorization Code Flow.
  • If the user successfully completed the login flow, the sidecar creates and stores a session. A corresponding session cookie is created and set before finally redirecting user agent to the application.
  • All requests that are forwarded to the upstream host will now contain an Authorization header with the user's access_token as a Bearer token, as long as the session is not expired or inactive.
• To log out, the user must be redirected to the /oauth2/logout endpoint.

Detailed documentation can be found in the documentation directory:

• Architecture
• Configuration
• Endpoints
• Usage
  • Session Management

Quickstart

See docker-compose.example.yml for an example setup:

docker-compose -f docker-compose.example.yml up

This starts:

• Wonderwall (port 3000) with Redis as the session storage
• http-https-echo (port 4000) as the upstream server
• mock-oauth2-server as the identity provider

Try it out:

1. Visit http://localhost:3000
   1. The response should be returned as-is from the upstream.
   2. The authorization header should not be set.
2. Visit http://localhost:3000/oauth2/login
   1. The authorization header should now be set in the upstream response.
   2. The response should also include the decoded JWT from said header.
3. Visit http://localhost:3000/oauth2/logout
   1. The authorization header should no longer be set in the upstream response.

Docker Images

Wonderwall is available on both GitHub Container Registry and Google Artifact Registry:

• ghcr.io/nais/wonderwall
• europe-north1-docker.pkg.dev/nais-io/nais/images/wonderwall

For available tags, see the versions overview on GitHub.

Verifying the Wonderwall image and its contents

The image is signed "keylessly" using Sigstore cosign. To verify its authenticity run

cosign verify europe-north1-docker.pkg.dev/nais-io/nais/images/wonderwall@sha25:<shasum> \
--certificate-oidc-issuer "https://token.actions.githubusercontent.com" \
--certificate-identity "https://github.com/nais/wonderwall/.github/workflows/deploy.yml@refs/heads/master"

The images are also attested with SBOMs in the CycloneDX format. You can verify these by running

cosign verify-attestation --type cyclonedx \
--certificate-identity "https://github.com/nais/wonderwall/.github/workflows/deploy.yml@refs/heads/master" \
--certificate-oidc-issuer "https://token.actions.githubusercontent.com" \
europe-north1-docker.pkg.dev/nais-io/nais/images/wonderwall@sha25:<shasum>

Development

Requires Go 1.23

docker-compose up -d
make local