Stored recovery codes were re-viewable two ways after their one-time
reveal. Both paths are now closed so codes are only viewable/downloadable
right after a fresh generation (enrollment or regenerate).
HOLE 1 — RecoveryCodes::$revealed was a mutable public Livewire prop, so
a crafted /livewire/update could flip it to true and make render() emit
stored codes. Annotated with #[Locked]; Livewire now rejects any
client-side write (set still happens server-side in mount()/regenerate()).
HOLE 2 — two-factor.recovery.download was auth-gated only, so any authed
user could GET it anytime to re-download stored codes. Added a one-time
session grant (2fa.download_grant) put alongside the existing
2fa.codes_fresh wherever codes are freshly generated (TwoFactorSetup,
WebauthnKeys, RecoveryCodes::regenerate); the route now
abort_unless(pull(grant), 403) before streaming — one download per fresh
generation, later direct hits 403.
Tests: lock rejection + download-grant lifecycle (forbidden → granted ok
→ consumed forbidden). Full suite 137 passed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>