* fix(security): mount host Docker socket only in aio (DooD) sandbox mode
The default Compose stack mounted /var/run/docker.sock read-write into the
root gateway container in every sandbox mode, including the default `local`
mode that never uses it -- an unnecessary host-escape surface (DooD =
root-equivalent host control). deploy.sh already gated the socket *check* on
sandbox_mode != local, but the Compose files mounted it unconditionally.
Move the socket mount to an opt-in docker/docker-compose.dood.yaml overlay
that deploy.sh / docker.sh append only when detect_sandbox_mode() returns
`aio`. Default (local) and provisioner/Kubernetes modes no longer expose the
host daemon. Tighten the socket existence check from != local to == aio.
Document the DooD threat model in SECURITY.md.
Reported by @greatmengqi.
* refactor(docker): address review on socket-hardening PR
- docker.sh: use absolute path for the dood overlay (match deploy.sh, drop cwd dependency)
- deploy.sh: drop now-dead DEER_FLOW_DOCKER_SOCKET exports in down/build paths
- docker-compose.yaml: fix stale header comment to point at the overlay
Addresses codex + reviewer feedback on #3517.
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Co-authored-by: Willem Jiang <willem.jiang@gmail.com>