feat(auth): OAuth allowed domains for self-hosted installs (#465)

[grootbro]

Summary

• Optional OAUTH_ALLOWED_DOMAINS (plus GOOGLE_ALLOWED_DOMAINS / GOOGLE_ALLOWED_DOMAIN fallback) for self-hosted OAuth
• Callback rejects users outside the allowlist (sign-in and sign-up)
• Matching-domain OAuth can create accounts when ALLOW_REGISTRATION=false
• Google: require verified email domain and ID token hd (Workspace)
• Docs + .env.template

Revives the direction from closed #428 on current main, as scoped in #465.

Fixes #465

Test plan

• No allowlist → OAuth unchanged
• OAUTH_ALLOWED_DOMAINS=example.com + Google Workspace user @example.com with hd → sign-in/sign-up works with ALLOW_REGISTRATION=false
• Same allowlist + personal Gmail / wrong domain → rejected at callback
• GitHub with allowlist: only verified primary emails on listed domains succeed
• CI: oauth-allowed-domains unit tests pass

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Summary by CodeRabbit

• New Features

  • Added OAuth email-domain allowlisting for Google and GitHub sign-in and registration.
  • Matching domains can register even when general registration is disabled.
  • Google Workspace domains are additionally verified against hosted-domain information.
  • Added support for global and Google-specific domain configuration, including fallback settings.

• Documentation

  • Documented OAuth domain restrictions, configuration precedence, and setup examples.
  • Updated the self-hosting environment template.

• Tests

  • Added coverage for domain parsing, provider-specific configuration, email validation, and Google hosted-domain checks.

[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between 0242cbd and 3aeca79.

📒 Files selected for processing (2)

• packages/auth/src/oauth-allowed-domains.test.ts
• packages/auth/src/oauth-allowed-domains.ts

🚧 Files skipped from review as they are similar to previous changes (2)

• packages/auth/src/oauth-allowed-domains.ts
• packages/auth/src/oauth-allowed-domains.test.ts

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📝 Walkthrough

Walkthrough

OAuth callbacks now enforce configurable email-domain allowlists for existing and new users. Google OAuth also validates the ID-token hd claim. Auth helpers, tests, exports, and self-hosting documentation support the new configuration.

Changes

OAuth domain allowlisting

Layer / File(s)	Summary
Domain rules and validation packages/auth/src/oauth-allowed-domains.ts, packages/auth/src/oauth-allowed-domains.test.ts, packages/auth/src/index.ts	Adds domain parsing, provider-aware configuration lookup, email-domain extraction, GitHub validation, Google hosted-domain validation, tests, and the public module export.
Callback enforcement and registration apps/api/src/controllers/oauth-callback.controller.tsx	Rejects disallowed existing and new OAuth users. Matching allowlisted domains can register when general registration is disabled. Google maps the hd claim to hostedDomain.
Configuration documentation apps/public/content/docs/self-hosting/environment-variables.mdx, apps/public/content/docs/self-hosting/self-hosting.mdx, self-hosting/.env.template	Documents OAUTH_ALLOWED_DOMAINS, Google-specific fallback variables, precedence, callback checks, and registration behavior.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 3aeca

This change adds optional OAuth domain restrictions while retaining unrestricted behavior when no allowlist is configured. No concrete merge-blocking risk remains.

Sequence Diagram(s)

sequenceDiagram
  participant OAuthProvider
  participant OAuthCallbackController
  participant OAuthDomainHelpers
  OAuthProvider->>OAuthCallbackController: Return OAuth user identity
  OAuthCallbackController->>OAuthDomainHelpers: Resolve configured domains
  OAuthCallbackController->>OAuthDomainHelpers: Validate email and hosted domains
  OAuthDomainHelpers-->>OAuthCallbackController: Allow or reject callback

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🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 22.22% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 9 functions across 4 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the OAuth allowed-domain feature for self-hosted installations.
Linked Issues check	✅ Passed	The changes implement the linked issue objectives: generic and Google-specific allowlists, legacy fallback behavior, callback enforcement, Google email and hosted-domain validation, registration when …
Out of Scope Changes check	✅ Passed	The code, tests, documentation, and environment-template updates directly support the linked OAuth domain restriction requirements. No unrelated changes are identified.

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Actionable comments posted: 2

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Inline comments:
In `@packages/auth/src/oauth-allowed-domains.test.ts`:
- Line 39: Update the “allows OAuth users when no allowlist is configured” test
to stub OAUTH_ALLOWED_DOMAINS to an empty string before the assertion, ensuring
isOAuthUserAllowedByDomain exercises the unrestricted-access branch regardless
of inherited environment values.

In `@packages/auth/src/oauth-allowed-domains.ts`:
- Line 27: Update the allowed-domain parsing in the OAuth configuration so
GOOGLE_ALLOWED_DOMAINS is parsed first, then fall back to GOOGLE_ALLOWED_DOMAIN
when the parsed plural value contains no domains. Preserve the resulting
allowlist behavior for configured plural domains and ensure an empty plural
setting cannot produce an unrestricted allowlist when the legacy value is
available.

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Review profile: CHILL

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📥 Commits

Reviewing files that changed from the base of the PR and between 3060ca1 and 0242cbd.

📒 Files selected for processing (7)

• apps/api/src/controllers/oauth-callback.controller.tsx
• apps/public/content/docs/self-hosting/environment-variables.mdx
• apps/public/content/docs/self-hosting/self-hosting.mdx
• packages/auth/src/index.ts
• packages/auth/src/oauth-allowed-domains.test.ts
• packages/auth/src/oauth-allowed-domains.ts
• self-hosting/.env.template

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[grootbro]

Addressed CodeRabbit: parse GOOGLE_ALLOWED_DOMAINS first, then fall back to GOOGLE_ALLOWED_DOMAIN; unrestricted-access test now clears allowlist env vars.