API security: lock down the fan-control surface#2
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The control API was unauthenticated on 0.0.0.0:8086 — any LAN host could pin fans at 1% indefinitely, and overrides bypassed the min/max clamp. - Bearer-token auth (api.token config key / API_TOKEN env) on all mutating endpoints (POST/DELETE override, POST/DELETE hint) via middleware with constant-time comparison. Read-only endpoints and dashboard stay open. - No-token mode: mutating requests restricted to loopback peers (403 otherwise, judged from RemoteAddr — forwarded headers ignored and spoof-proof), with a loud startup warning. - Overrides clamped to min_speed/max_speed at the controller layer (plus defense-in-depth in calculateTarget); duration capped at 24h so overrides can no longer be infinite. Critical-temp emergency ramp still beats any override. - Stored XSS fixed: hint/GPU/CPU fields escaped before innerHTML in the dashboard; server-side hint validation (charset, length, closed sets) rejects script payloads outright. - api.token excluded from /api/config responses; no request logging that could leak it. - Docs: README API Security + migration note, config.example.yaml exposure comments, unraid template masked API_TOKEN field, hint-client.sh sends the bearer token (and its lost exec bit is restored). Tests: httptest coverage for the full auth matrix, loopback/spoofing, clamping, validation, token non-leakage. go vet and go test -race clean. Task: dex ttm1g3x0 - Tier 2: API security Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EQmqj1Hj8DL3GGAcBDNm8v
This was referenced Jul 17, 2026
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Summary
Stacked on #1 — merge that first, then retarget/merge this.
The control API was unauthenticated on
0.0.0.0:8086: any LAN host could pin fans at 1% indefinitely, overrides bypassed the speed clamp, and the dashboard had a stored XSS via hint fields. This PR closes all three:api.token/API_TOKENenv) on all mutating endpoints, constant-time comparison, token never leaked via/api/configor logs. Read-only endpoints and the dashboard stay open.X-Forwarded-Forspoofing tested and ineffective), loud startup warning.min_speed/max_speedat the controller layer; duration capped at 24h (no more infinite overrides). Critical-temp emergency ramp still beats any override — regression-tested live.innerHTML.config.example.yamlexposure comments, Unraid template maskedAPI_TOKENfield,hint-client.shsends the bearer token.Backward compatible: existing deployments keep working; adding a token is a config-only change.
Review & verification
2cka7723); reviewer independently probed loopback-bypass edge cases (IPv6 zones, mapped addresses, malformed peers — all fail closed) and confirmed zero Tier 1 safety regression.go vet+go test -race -count=1 ./...clean; newinternal/apihttptest suite covers the auth matrix.hint-client.shruns against a token-protected server, speed-100 request clamped to 80, duration-0 capped at exactly 24h, XSS payload rejected, critical ramp beat an active low override in one tick.Task: dex ttm1g3x0 — Tier 2: API security
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