- dav_router: PUT now looks up the event within the authenticated calendar only
(local_events.uid is globally unique), so a CalDAV client can no longer
overwrite another user's/calendar's event; a cross-calendar UID clash returns
409 instead of a 500 from the UNIQUE constraint.
- ical_router: _fetch_ics validates the URL (http/https only), resolves the host
and rejects private/loopback/link-local/reserved targets, follows redirects
manually re-validating each hop, and caps the response size — closing an
authenticated SSRF into internal services / cloud metadata.
- profile_router: GET /profile/avatar/{user_id} now requires authentication.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
CalDAV clients send only user+password over Basic Auth and can't provide a TOTP
code, so account passwords would bypass 2FA. Add revocable app passwords:
- models: AppPassword table (bcrypt hash, label, last_used); auto-created via
create_all
- profile_router: GET/POST/DELETE /profile/app-passwords (plaintext shown once)
- dav_router: Basic Auth accepts any app password; the account password is
accepted only when 2FA is disabled
- frontend: "App-Passwörter (CalDAV)" section in the profile modal (create/show-
once/copy/revoke) + i18n (de/en); login hint now says app password
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Findings from the security review:
- HIGH: private local events leaked in full (title/location/description) to
anyone who could READ a shared or group calendar via GET /api/caldav/events —
the private_event_visibility rule was only enforced in /groups/{id}/combined.
Now enforced in the merge read too, via a shared helper (apply_event_privacy)
so the two paths can't drift.
- HIGH: 'busy' masking was a blacklist that still leaked creator identity,
source-calendar name, recurrence rule and per-event colour. Replaced with a
whitelist (mask_busy_event): only timing/identity/render fields survive.
- MEDIUM: .ics import had no size limit (raw = await file.read()) → memory DoS.
Now capped at 5 MB (413), read before creating any calendar.
- LOW/INFO: profile email now checked for uniqueness + basic format; display
name / username / email length-capped and control-chars stripped.
Deferred (tracked): RRULE expansion cap at the trust boundary, SQLite
PRAGMA foreign_keys + ON DELETE cascade, and JWT-by-user-id + token version.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
