The Interface tab carried data-demo-lock as a whole, which greyed out the
sidebar layout breakpoint along with the toast settings. The breakpoint is
localStorage — per browser, invisible to every other visitor — so it belongs
with theme, notification permission and the quick-access bar, all of which
were already allowed. The toast settings are server-side and shared, so the
lock moves onto the uiSettingsForm that owns them.
Audited every other locked region against the localStorage key list: this was
the only per-browser control caught by a lock. Notifications, theme, FAB
placement/size/position and the sidebar breakpoint are now the complete set of
preferences a demo visitor may change.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
mc-webui has no login, which is fine on a LAN and not fine once the
address is handed to testers: they assume the node is theirs and rename
it, and the console is right there for anyone curious enough to type
into it.
MC_DEMO=true refuses everything that reconfigures the radio, destroys
data, reaches other people's repeaters, rebuilds the containers,
publishes to an external broker, or hands out a secret. Reading and
sending messages keep working, so the instance is still worth visiting.
The guard is default-deny: an api_bp.before_request hook refuses every
non-GET unless it is on a short allowlist, so an endpoint added later is
locked without touching this module. That mattered — six mutating
endpoints already had no frontend caller and would never have made a
hand-written blacklist. A small read denylist covers the GETs that leak
(repeater passwords, backup download, capture download, /api/logs),
which the write guard never sees.
Two paths bypass the HTTP layer and are closed separately: the console
is a Socket.IO event, not a route, so it is checked against a read-only
command set; the log viewer is refused at the connect handshake.
Access is kept two ways. MC_DEMO_TRUSTED_NETS unlocks by CIDR, and
MC_DEMO_UNLOCK_CODE unlocks by a code typed once in Settings and held in
an HMAC cookie for 30 days — stateless, and deliberately not Flask's
session, whose SECRET_KEY is a hardcoded public constant.
The trap the network list walks into: published through a tunnel, every
visitor arrives from the tunnel's address, and if the tunnel runs on the
LAN then trusting the LAN unlocks the instance for the whole internet.
An address arriving with a proxy header is therefore not matched unless
MC_TRUST_PROXY is on, and startup logs report the resulting shape.
Frontend is advisory only: demo-lock.js loads from _head_i18n.html so it
reaches all eight entry points including the six iframes, greys out
[data-demo-lock] rather than hiding it (the instance exists to show the
app off), re-applies via MutationObserver for JS-rendered buttons, and
turns any 403 demo_locked into a toast.
Verified on the local container: the rename, reboot, updater, vacuum,
cleanup and the leaky GETs all 403; sending, read markers and ordinary
reads pass; `set name` is refused over the console socket while `infos`
still answers; unlock/lock round-trips. 86 new unit tests, en/pl at 100%.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
