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HeliosDB HeliosProxy

Demo 8 — `trust_root` config knob

Demo 8 — trust_root config knob

Module brief: §Module 8

UVP

One TOML knob — [plugins].trust_root — flips the proxy from permissive (load any .wasm) to enforced (only signed plugins from the trust root). Same binary; deploy to dev or prod with different config.

Use cases

  • Dev → prod promotion. Local dev box has trust_root unset; CI pipeline sets it to a sealed key directory; same binary, same config layout.
  • Compliance gate. SOC 2 evidence is “this prod proxy started with trust_root configured.” Operators can grep proxy.toml to prove it.

What this demo shows

Two proxy.toml files in this directory:

  • proxy.permissive.toml — no trust_root. Loads anything.
  • proxy.enforced.toml — trust_root = "/etc/helios/keys". Only loads signed plugins.
Terminal window
# Permissive: drop in an unsigned cost-governor.wasm; loads.
docker compose --env-file=permissive.env up -d
docker compose logs proxy | grep "loaded plugin"
# → INFO loaded plugin helios-plugin-cost-governor v0.1.0


# Enforced: same .wasm without a signature → refuses to load.
docker compose down
docker compose --env-file=enforced.env up -d
docker compose logs proxy | grep -i "signature"
# → WARN plugin cost-governor.wasm requires a sidecar .sig file
#        (trust root active)


# Sign it + restart → loads.
openssl pkeyutl -sign -inkey keys/signing.pem -rawin \
  -in plugins/cost-governor.wasm | base64 -w 0 > plugins/cost-governor.sig
docker compose restart proxy
docker compose logs proxy | grep "signed_by"
# → INFO plugin signature verified, signed_by=release-key

Implementation pointer

  • TOML field: src/config.rs::PluginToml.trust_root: Option<String>
  • Runtime config: src/plugins/config.rs::PluginRuntimeConfig.trust_root: Option<PathBuf>
  • Activation: src/plugins/mod.rs::PluginManager::load_plugin reads runtime.config().trust_root and conditionally attaches the SignatureVerifier.

HeliosDB compatibility

Backend-agnostic.