Files
ServerKit/backend/app/utils
Juan DenisandClaude Opus 4.8 363a09dc7e feat(security): trust reverse-proxy client IP via one gated seam
Rate-limit buckets, login lockout and audit-log source IPs hand-parsed the
leftmost X-Forwarded-For token — a client-controlled value — letting an
attacker rotate it to dodge per-IP limits or forge audit trails.

- config: add TRUST_PROXY_HEADERS / TRUSTED_PROXY_HOPS (+ _env_bool/_env_int)
- create_app: wrap in gated Werkzeug ProxyFix (rightmost trusted hops) before
  the limiter/handlers so every remote_addr consumer sees the real client
- new app/utils/client_ip.py::get_client_ip() — the single trusted seam
- replace all six leftmost-XFF parsers (rate_limit, audit middleware,
  api_key_auth, api_analytics, audit_service, ddns) with get_client_ip()
- deploy: root .env.example ships TRUST_PROXY_HEADERS=true (behind nginx);
  backend/.env.example documents it off for dev
- tests: test_trusted_client_ip.py (7) incl. real flask-limiter bucket isolation

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-18 00:51:21 -04:00
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