08 — User Management

1. User model

User {
  id, username, display_name, email,
  password_hash (argon2id),   // absent for directory-sourced users
  auth: { totp_enabled, webauthn_credentials[] },
  role: admin | operator | user | viewer,
  groups: [Group],
  home_subvolume, quota { soft, hard, used },
  status: active | locked | pending,
  metadata: { created_at, last_login_at, must_change_password, ssh_keys[] }
}
Group { id, name, members[], default_share_permissions? }

• Built-ins: admin (first account, created at install — never removable, renameable), backup (service account used by backup jobs), guest (disabled by default; drives guest-access shares).
• Users map 1:1 to POSIX users on the host, with home subvolumes under @data/homes/<user>. SMB, SFTP, FTP, and rsync all authenticate against this same account store, so a password change propagates everywhere at once.

2. Roles and permissions

Role	Shares (own)	Shares (granted)	Apps	Backups	Users & security	System settings	Pool/disk
admin	rw	rw	manage	manage	manage	manage	manage
operator	rw	rw	manage	manage	view only	view only	—
user	rw	per grant	use	own jobs only	—	—	—
viewer	ro	ro	use (read-only)	—	—	—	—

• Custom roles: admin-defined permission sets drawn from the API catalog (e.g., "media-manager": shares.read, apps.manage(jellyfin, plex)).
• Permission checks are centralized in onyx-core policy evaluation; the UI renders based on the same checks, and the protocol daemons enforce equivalent grants via config.
• Effective access = role ∪ group grants ∪ per-share grants, with deny-overrides for explicit blocks (e.g., a group is granted a share, one member is blocked).

3. Share and quota management

• Share grants are per user/group with read / read-write; visible in both directions (user view: "You can access: Photos (rw), Family (ro)").
• Quotas: per-user soft/hard on the home subvolume; per-share quotas at the share subvolume. Soft → warning banner + notification; hard → writes blocked with a clear UI message. Admins get a quota overview table with usage bars and one-click "grant more".
• Quota inheritance: a group can carry a default quota applied to new members.

4. Authentication methods per user

Method	Local users	Directory users
Password (argon2id)	✅ (2FA optional/required by policy)	via LDAP/AD bind
TOTP	✅	✅ (local 2FA)
WebAuthn / passkey	✅	✅
SSH key	✅ (SFTP/SSH)	via directory
App token	✅ scoped	✅ scoped
OIDC SSO	optional identity link	✅ primary

• 2FA policy: admin can require 2FA for all admins, all users, or leave optional. First-login wizard nudges 2FA for admin accounts ("takes 30 seconds").
• Password policy: minimum 12 chars, optional complexity; password change forces token revocation for that user (except long-lived app tokens, which get an expiry notice).
• Lockout: 5 failed attempts → 15 min lock, exponential backoff; admins unlock; failed logins feed the security notification stream.

5. Lifecycle and onboarding

1. Install: create the first admin (username, strong password, 2FA prompt).
2. Invite: admin adds a user → invite link/email with a one-time token (expires 72 h) → user sets own password + 2FA. No shared passwords ever.
3. Daily use: user logs in, sees only their home + granted shares + permitted apps.
4. Suspension: lock user (session revoked, SMB/SFTP denied, apps stopped for that identity); data retained.
5. Deletion: typed confirmation; data moved to a deleted-<user>-<ts> snapshot first (retention per policy, default 30 days), then removable — never silent.

6. Directory integration (optional)

• OIDC: add provider (discovery URL + client credentials) → "Sign in with " appears on the login screen; group claims map to Onyx groups; a local admin break-glass account is always kept.
• LDAP/AD: join the domain; users/groups sourced from the directory (read-only reference), Onyx roles assigned via group mapping rules (e.g., CN=NAS-Admins → admin). Passwords validated by the directory; Onyx never stores them.
• Scope guard: directory-sourced users get the user role by default until an admin maps them; misconfigurations never grant admin implicitly.

7. Session and device management

• "Devices" page lists active sessions (browser, CLI, mobile, WebDAV clients) with last-seen, IP, and user-agent; per-device revoke and "revoke all".
• Concurrent session limit per user (default 10) with oldest-eviction; admin override.
• Password/2FA changes revoke sessions except current device, with a confirm prompt.

8. Delegation (v1.5+, designed now)

• Share links: expiring, password-optional links to files/folders for people without accounts (download-only or upload-only drop boxes) — implemented as scoped app tokens bound to a single path; the Links page lists, expires, and revokes them.
• Operator delegation: an admin can grant a user operator on a subset of shares ("manage family share, nothing else") via custom roles.

9. Audit and privacy for users

• Users can view the audit entries that concern them (own logins, own file actions) in a "My activity" view — transparency without exposing other users' data.
• Admins see the full audit log; user-level exports available for compliance (small business) — see 07-security-model.md.