Fixes from the PR #23 adversarial review (graded 35 real / 1 false positive):
Security / correctness
- Race-free registration: is_admin and the registration gate are now
computed atomically inside a single INSERT...SELECT, so concurrent
first registrations can't both become admin or bypass closed
registration (fixed the whole TOCTOU cluster).
- Sliding session now reaches the browser: ResolveSession returns the
current expiry and requireAuth re-sets the cookie, so active users
aren't logged out 30 days after login regardless of activity.
- Login CSRF: csrfGuard rejects state-changing requests whose Origin
doesn't match PANSY_BASE_URL (no-op when unset, so the dev proxy is
unaffected). SameSite=Lax alone didn't cover this.
- argon2id tuned to RFC 9106's second recommended profile (t=3).
- Timing equalizer can't fail open: the dummy hash is derived
deterministically (fixed salt, no RNG) so it's always present.
- Password length (<=1024) enforced in the service for both register
and login, not just HTTP binding tags; login rejects over-long input
before spending argon2 work.
Error handling / robustness
- Login logs a malformed stored hash instead of silently treating it as
a wrong password.
- Best-effort session writes (Touch/Delete during renewal, expiry, and
corrupt-expiry cleanup) now log on failure.
- index sessions.expires_at via new migration 0002 (0001 is immutable).
Maintainability
- Extract startSessionAndRespond and abortUnauthenticated; make
writeServiceError a free function; consistent error handling in
decodeHash; doc/comment fixes.
Tests: over-long password, CSRF guard (cross-origin/same-origin/dev
no-op), and cookie refresh on authenticated requests; migration-version
assertions bumped to 2.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01JdQpdYYsTgtkJBxbcpAszi
