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
AI Chat is a plain scratchpad for talking to a model directly — no story
context, scripts or world state — for poking at models, prompts and endpoints
without starting an adventure. Power users only: the router 404s (rather than
403s) for everyone else and the nav link is hidden. The conversation lives in
localStorage, so there's no new table or migration.
is_power_user() now also returns True in local mode: it's the operator's own
machine and their own key, the same reasoning that makes the provider debug log
local-only.
Alongside that, the rule keeping the shared demo key off paid models now lives
in exactly one place. It had been duplicated into the chat router, which is how
one copy eventually drifts:
- resolve_provider_config() takes an optional model_override and is the only
place the whitelist is applied, so turns, AI Chat and the connection test all
inherit it. An override is a per-request preference, never a grant.
- ProviderConfig.__post_init__ refuses to exist when api_key is the demo key
and the model isn't whitelisted. It keys on the key itself rather than the
using_demo flag, so a mislabelled config can't slip past, and it raises so a
future path that bypasses the resolver fails loudly instead of billing.
- The demo branch still pins endpoint_url too — a user-controlled endpoint
would leak the key itself, which is worse than spending it.
Provider gained chat(messages, ...) beside generate(), both delegating to a
shared _stream(url, body); completion-mode endpoints get the messages flattened
into a labelled transcript. Settings' /models fetch moved to
list_endpoint_models() and is shared with /api/chat/config.
Tests: 10 new in tests/test_chat.py (70 total). These deliberately do not stub
resolve_provider_config — the point is to exercise the real BYOK-vs-demo
decision and assert on what the provider actually received: off-whitelist
override pinned, off-whitelist Settings.model pinned, redirected endpoint
pinned, BYOK passed through untouched.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014FGY1yvzSeKgTtRfeVtDmx
Config via env, abuse/resource limits, and production serving so the app
is safe to expose publicly:
- Fail-fast on missing SECRET_KEY when MULTI_USER=true
- quickjs per-execution time/memory limits (while(true) can't hang server)
- Per-user/per-IP rate limiting on turn/script/auth endpoints
- Request body size limit + per-user row caps
- Security headers (CSP, X-Frame-Options, nosniff, referrer-policy) incl. SSE
- Debug router 403 and /docs disabled in multi-user mode
- DATABASE_URL support (defaults to Neon Postgres) alongside SQLite
- Documented all env vars in backend/.env.example
Verified locally via uvicorn (MULTI_USER=1, SQLite); see plan/09-phase-hardening.md.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017e6tQuojBLYPetUfmhit4X
