Found while checking whether the /lnd-connect-info leak (a05956c4) was
also reachable over Tor. It was not — but only by accident, and the
accident was one app id away from failing.
auto_add_tor_service() creates a hidden service for a freshly installed
app, mapping onion:80 -> 127.0.0.1:<the app's host port>. It skips the
node's own service and is_protocol_service() — which names the DAEMONS
(bitcoin, bitcoin-knots, electrs, electrumx, lnd) but NOT their UI
sidecars. lnd-ui and bitcoin-ui are real, installable app ids
(apps/lnd-ui, apps/bitcoin-ui) whose host ports are 18083 and 8334:
exactly the two ports that served the admin macaroon and the
credential-injecting Bitcoin RPC proxy.
So nothing structural prevented either from acquiring a GLOBAL onion as
a silent side effect of being installed — re-exposing worldwide, and
persistently, what a05956c4 had just closed to mesh/LAN peers. Verified
on a live node that this has not fired (services.json maps lnd to 8080
and holds no *-ui entry, and the running torrc contains neither port),
so this closes a latent hole rather than an active one.
The gate gets its own named predicate rather than an addition to
is_protocol_service, because the two express different things:
is_protocol_service says "this speaks a wire protocol, not HTTP", while
never_auto_onioned says "this fronts the node's money and must not be
published unasked". Conflating them would have made the fix look like a
classification tweak.
This gates only the AUTOMATIC path. An operator who deliberately enables
Tor for one of these apps still can — that is an informed choice, not a
silent default. Both endpoints are session-gated at the backend as of
a05956c4 either way.
Compile-checked clean.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
