2 Commits

Author SHA1 Message Date
root
814197cfd3 ADR-006: auth posture for non-loopback deploy + token rotation impl
ADR-003 locked the auth substrate; ADR-006 ratifies the operator
playbook + adds two implementation pieces needed for Sprint 4
deployment: env-resolved tokens and dual-token rotation.

Six decisions locked in docs/DECISIONS.md:
- 6.1: Non-loopback bind requires auth.token (mechanical gate at
       shared.Run, already implemented; this ratifies it).
- 6.2: Token from env, not TOML. /etc/lakehouse/auth.env (mode 0600)
       loaded by systemd EnvironmentFile=. New TokenEnv field on
       AuthConfig defaults to "AUTH_TOKEN".
- 6.3: AllowedIPs for inter-service same-trust-domain; Token for
       cross-trust-boundary (gateway ↔ external).
- 6.4: /health stays unauthenticated; everything else under
       shared.Run is gated. Already implemented; ratified here.
- 6.5: Token rotation is dual-token. New SecondaryTokens []string
       on AuthConfig — both primary and any secondary pass auth
       during the rotation window. Implemented in this commit.
- 6.6: TLS terminates at the network edge (nginx/Caddy), not
       in-process. Daemons stay HTTP-only; internal traffic stays
       on private subnets per Decision 6.3.

Implementation:
- internal/shared/config.go: AuthConfig gains TokenEnv +
  SecondaryTokens fields. New resolveAuthFromEnv() called by
  LoadConfig fills Token from os.Getenv(TokenEnv) when Token is
  empty. TokenEnv defaults to "AUTH_TOKEN" so the happy path needs
  no TOML config.
- internal/shared/auth.go: RequireAuth pre-encodes Bearer headers
  for primary + every secondary token; per-request constant-time
  compare walks the slice. Fast path is 1 compare (primary).

Tests:
- TestLoadConfig_AuthTokenFromEnv (3 sub-tests): default env name,
  custom token_env, explicit Token wins over env.
- TestRequireAuth_SecondaryTokenAccepted: both primary + secondary
  tokens pass during rotation window.
- TestRequireAuth_SecondaryTokensOnly: only-secondary path works
  for the case where primary was just promoted-to-empty mid-rotation.

go test ./internal/shared all green; existing auth_test.go
unchanged (constant-time compare path preserved).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-30 17:51:14 -05:00
root
fa56134b90 ADR-003 wiring: Bearer token + IP allowlist middleware
Implements the auth posture from ADR-003 (commit 0d18ffa). Two
independent layers — Bearer token (constant-time compare via
crypto/subtle) and IP allowlist (CIDR set) — composed in shared.Run
so every binary inherits the same gate without per-binary wiring.

Together with the bind-gate from commit 6af0520, this mechanically
closes audit risks R-001 + R-007:
  - non-loopback bind without auth.token = startup refuse
  - non-loopback bind WITH auth.token + override env = allowed
  - loopback bind = all gates open (G0 dev unchanged)

internal/shared/auth.go (NEW)
  RequireAuth(cfg AuthConfig) returns chi-compatible middleware.
  Empty Token + empty AllowedIPs → pass-through (G0 dev mode).
  Token-only → 401 Bearer mismatch.
  AllowedIPs-only → 403 source IP not in CIDR set.
  Both → both gates apply.
  /health bypasses both layers (load-balancer / liveness probes
  shouldn't carry tokens).

  CIDR parsing pre-runs at boot; bare IP (no /N) treated as /32 (or
  /128 for IPv6). Invalid entries log warn and drop, fail-loud-but-
  not-fatal so a typo doesn't kill the binary.

  Token comparison: subtle.ConstantTimeCompare on the full
  "Bearer <token>" wire-format string. Length-mismatch returns 0
  (per stdlib spec), so wrong-length tokens reject without timing
  leak. Pre-encoded comparison slice stored in the middleware
  closure — one allocation per request.

  Source-IP extraction prefers net.SplitHostPort fallback to
  RemoteAddr-as-is for httptest compatibility. X-Forwarded-For
  support is a follow-up when a trusted proxy fronts the gateway
  (config knob TBD per ADR-003 §"Future").

internal/shared/server.go
  Run signature: gained AuthConfig parameter (4th arg).
  /health stays mounted on the outer router (public).
  Registered routes go inside chi.Group with RequireAuth applied —
  empty config = transparent group.
  Added requireAuthOnNonLoopback startup check: non-loopback bind
  with empty Token = refuse to start (cites R-001 + R-007 by name).

internal/shared/config.go
  AuthConfig type added with TOML tags. Fields: Token, AllowedIPs.
  Composed into Config under [auth].

cmd/<svc>/main.go × 7 (catalogd, embedd, gateway, ingestd, queryd,
storaged, vectord, mcpd is unaffected — stdio doesn't bind a port)
  Each call site adds cfg.Auth as the 4th arg to shared.Run. No
  other changes — middleware applies via shared.Run uniformly.

internal/shared/auth_test.go (12 test funcs)
  Empty config pass-through, missing-token 401, wrong-token 401,
  correct-token 200, raw-token-without-Bearer-prefix 401, /health
  always public, IP allowlist allow + reject, bare IP /32, both
  layers when both configured, invalid CIDR drop-with-warn, RemoteAddr
  shape extraction. The constant-time comparison is verified by
  inspection (comments in auth.go) plus the existence of the
  passthrough test (length-mismatch case).

Verified:
  go test -count=1 ./internal/shared/  — all green (was 21, now 33 funcs)
  just verify                            — vet + test + 9 smokes 33s
  just proof contract                    — 53/0/1 unchanged

Smokes + proof harness keep working without any token configuration:
default Auth is empty struct → middleware is no-op → existing tests
pass unchanged. To exercise the gate, operators set [auth].token in
lakehouse.toml (or, per the "future" note in the ADR, via env var).

Closes audit findings:
  R-001 HIGH — fully mechanically closed (was: partial via bind gate)
  R-007 MED  — fully mechanically closed (was: design-only ADR-003)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-29 07:11:34 -05:00