fix(rate-limit): stop trusting X-Forwarded-For / X-Real-IP by default - #229
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The default "ip" rate-limit key strategy honored X-Forwarded-For and X-Real-IP unconditionally, with no trusted-proxy check. Any client could bypass its rate limit by sending a fresh value on each request, or frame another client by spoofing its IP in the header. The default "ip" strategy now keys on the actual TCP peer address (scope.client) only, which the client cannot control. A new opt-in strategy, "trusted-forwarded-ip" (aliased "forwarded-ip"), restores the X-Forwarded-For / X-Real-IP behavior for deployments that are actually behind a reverse proxy overwriting those headers. Also fixes scope.client parsing: Granian's RSGI scope exposes it as a "host:port" string, but the old code indexed it with get_item(0) as if it were an ASGI-style (host, port) tuple, silently returning only the first character of the string. scope_client_host() now handles both the RSGI string form and the ASGI/test-scope tuple form. Closes #207
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Problem
The default
rate_limit_key="ip"strategy honoredX-Forwarded-For/X-Real-IPunconditionally, with no trusted-proxy check. Any client could:Fix
"ip"now keys on the actual TCP peer address (scope.client) only — the client cannot control this."trusted-forwarded-ip"(alias"forwarded-ip") restores theX-Forwarded-For/X-Real-IPbehavior, documented as safe only behind a reverse proxy that actually overwrites those headers.scope.clientparsing assumed an ASGI-style(host, port)tuple viaget_item(0), but Granian's real RSGI scope exposes it as a"host:port"string — so the old "safe" fallback was silently returning just the first character of that string. Addedscope_client_host()to handle both forms correctly.Testing
tests/test_rate_limit.py: the existing test asserted the vulnerable behavior (spoofed X-Forwarded-For not blocked) — flipped to assert it's now blocked, since it's the same underlying peer.test_trusted_forwarded_ip_opt_incovering the new explicit opt-in strategy.cargo test --lib rate_limit: 2 passed.pytest tests/): 161 passed, 1 skipped.docs/rate-limiting.md.Closes #207