The per-IP rate limits could be bypassed entirely: uvicorn ran with
--forwarded-allow-ips "*", which trusts the leftmost X-Forwarded-For value
(client-controlled), and Render forwards the inbound header rather than
stripping it. Rotating the header handed out a fresh rate-limit bucket per
request, so the login/register limit (10/5min) and guest-minting limit
(30/5min) were no throttle at all — unbounded password guessing and guest-row
creation. Confirmed live: fixed IP -> 429 after 10; rotating spoofed header ->
no 429 across 14 attempts.
Two-layer fix:
- limits._client_ip now derives the client IP from the hop the trusted edge
appends (rightmost of X-Forwarded-For), which a client can't spoof past;
tunable via AIDND_TRUSTED_PROXY_HOPS. Dropped --forwarded-allow-ips "*".
- New per-account login throttle (email-keyed, 8 fails / 15 min, cleared on
success): stops distributed guessing against one account that a per-IP limit
can't, since it can't be diluted across many source addresses.
Also close an SSRF on the BYOK endpoint_url (hosted mode only): the connection
test and turn/chat streams now refuse a URL that resolves to a non-public
address (private/loopback/link-local metadata/reserved), checked at request
time so it resists a DNS record flipping to a private IP. No-op locally, where
reaching localhost Ollama is intended.
Tests: test_ratelimit_hardening.py (8), test_netguard.py (13). 172 pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015CYEJKobJ2Re4Dv7qUoSA7
