Edge nodes are deployed to arbitrary locations by arbitrary people, so the
broker has to be reachable from the internet and secured on its own merits
rather than by a VPN.
Three defects made that impossible. The broker only had a plaintext 1883
listener; every node shared one drb-node password; and the ACL pattern used
%c, the client-supplied client id, so any holder of that shared password
could set client_id to another node and take over its namespace. The comment
claiming this cryptographically prevented cross-node access was wrong and is
gone.
Authentication now uses mosquitto 2.x's built-in dynamic-security plugin on
the stock eclipse-mosquitto image. c2-core administers it over the control
topic, creating each node's client on approval with username=<node_id> and
password=<its node_keys api_key>, attached to a role whose ACL is nodes/%u/#
against the authenticated username. One credential, one revocation point.
An HTTP-callback plugin was implemented first and rejected: that project is
archived upstream, which is not an acceptable dependency on an
internet-facing broker.
Because dynsec state is a second source of truth alongside Firestore,
approve/reissue/delete now write to the broker first and surface a 502
rather than drifting, and c2-core reconciles every approved node into dynsec
on startup.
Adds node self-enrollment (POST /nodes/enroll, GET /nodes/{id}/credentials)
so a new node can obtain its key over HTTPS without an operator handling
secrets by hand. Enrolling an already-approved node_id is refused on the
fleet token alone — otherwise a leaked token plus a guessable id would let
an attacker steal a live node's key before the real node asked for it.
Pickup secrets are stored hashed and returned once, and the endpoint is rate
limited per source IP.
Infrastructure: an 8883 TLS listener fed by Caddy's certificate via a
systemd path unit, a firewall rule for it, and Caddy now 404s /internal/*
so the api vhost cannot proxy internal routes.
Also fixes CORS, which allowed https://app.<domain> while the frontend is
served on the bare domain — every call from the portal would have failed —
and widens the vault gitignore to a glob, since ansible-vault leaves
backup siblings that the exact-name rule left committable.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
27 lines
1.4 KiB
Bash
27 lines
1.4 KiB
Bash
# Top-level docker-compose environment variables
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# Copy to .env and fill in values before running `docker compose up`
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# -----------------------------------------------------------------------
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# MQTT broker credentials
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# These are injected into the mosquitto container at startup to build the
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# password file. Use different values in production — do NOT reuse defaults.
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# -----------------------------------------------------------------------
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# C2-core service account (full broker access via the "c2core" dynsec role)
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MQTT_C2_USER=drb-c2-core
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MQTT_C2_PASS=change-me-c2
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# Seeds mosquitto's built-in dynamic-security plugin's one-time "admin"
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# bootstrap client on first boot (read directly by mosquitto, no entrypoint
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# scripting involved). Must be >=12 chars. c2-core needs this SAME value as
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# MQTT_DYNSEC_ADMIN_PASS in drb-c2-core/.env to log in as "admin" and
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# administer node credentials — see app/internal/dynsec.py.
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MOSQUITTO_DYNSEC_PASSWORD=change-me-dynsec-admin-min-12-chars
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# There is no shared node credential anymore. Each node authenticates as
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# username=<node_id>, password=<its node_keys.api_key> — checked by
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# mosquitto's dynamic-security plugin (not an HTTP backend — that was an
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# earlier, since-rejected design using the now-archived mosquitto-go-auth).
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# Nodes obtain that key via the enrollment flow — see ENROLLMENT_TOKEN in
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# drb-c2-core/.env.example.
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