feat(chart): add an egress NetworkPolicy - #51
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The renamed Argo app reads env/prod.yaml only, and the hub-prod app is gone. This file is dead.
DNS plus public HTTP/HTTPS only; every private range is excluded. The app fetches MCP servers at a URL supplied by the request, so without this a crafted server_url reaches internal services. Ingress restriction is gated off for now and its allow-list comes from the deployment layer.
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What
Adds a NetworkPolicy to the chart, enabled in prod. It is egress-only in this PR: DNS plus public HTTP/HTTPS, and nothing else. Every private range is excluded, so the app can no longer open connections to anything on the internal network.
Why
The app is a server-side fetcher: it connects to the upstream router and to MCP servers whose URL comes from the request (
server_urlin the request schema). Today the pod has unrestricted egress, so a craftedserver_urlcan reach internal services (databases, caches, the Kubernetes API). This policy removes that reachability at the network layer, independently of any application-side validation.Observed egress over a 2-hour window was public 443 only, which this policy allows (80 is allowed too, since MCP endpoints in the wild are not always TLS).
Notes
networkPolicy.ingress.enabled: false). It comes in a follow-up, after a canary on another app, because a wrong load-balancer range would black-hole traffic. The allow-list itself is supplied by the deployment layer, never committed here.enabledis a values flag, so rollback is a one-line revert.exceptblocks are the standard RFC1918 + link-local ranges; the link-local one also covers the instance metadata endpoint (defense in depth — the nodes already run with a metadata hop limit of 1).