Tailscale-style sidecar pattern: a FIPS container provides mesh
networking, and a companion app container shares its network namespace
via network_mode: service:fips.
Security model:
- iptables enforces strict isolation — the app container can only
communicate over the FIPS mesh (fd::/8 via fips0)
- No IPv4 access: eth0 restricted to FIPS UDP transport (port 2121)
- No IPv6 on eth0: ip6tables blocks all eth0 IPv6 traffic
- Only fips0 and loopback are reachable from the app container
The sidecar accepts peer configuration via environment variables
(FIPS_NSEC, FIPS_PEER_NPUB, FIPS_PEER_ADDR), so it can be pointed
at any FIPS node without config file generation.
Files:
- testing/sidecar/: Dockerfile, Dockerfile.app, docker-compose.yml,
entrypoint.sh, .env, resolv.conf, scripts/build.sh
- testing/sidecar/README.md: security model, quick-start, architecture,
DNS resolution, troubleshooting, production considerations
- testing/sidecar/scripts/test-sidecar.sh: 3-node chain integration
test verifying link establishment, multi-hop connectivity, and
network isolation on each app container
- .github/workflows/ci.yml: sidecar integration test matrix entry
Three-job pipeline:
- build: matrix over ubuntu/macos/windows, native cargo build per runner;
macOS and Windows are continue-on-error (best-effort). Uploads Linux
binary as artifact for downstream jobs.
- test: cargo test --all on ubuntu, gated on build succeeding.
- integration: parallel matrix of static-mesh, static-chain, and
chaos-smoke-10; runs only when build + test both pass. Static jobs
use docker compose + ping-test.sh; chaos job runs the stochastic
simulation via chaos.sh.
Johnathan Corgan
origami74@gmail.com