Operator tool for the fix in a05956c4. GET /lnd-connect-info answered
unauthenticated callers with the LND ADMIN MACAROON, the TLS cert, the
gRPC/REST ports and the node's onion address. Every macaroon on an
affected node must be treated as known to an attacker.
Rotation removes the macaroon root key from macaroons.db plus the issued
macaroon files; LND mints a fresh root key on unlock, so every
previously issued macaroon — including any the attacker holds — stops
verifying. Coins live in wallet.db and channel state in channel.db, and
macaroons are bearer tokens rather than keys, so neither database is
touched, opened or moved.
Safety properties, in the order they matter:
- Detect-only by DEFAULT. --apply additionally requires --yes.
- An ORDERING GUARD refuses to rotate on a node whose binary lacks the
fix, because the new macaroon would leak through the same door within
seconds and the operator would believe they were safe. Overridable
only via an explicit --force-unpatched.
- It backs up the old material to a 0700 dir OUTSIDE the dir LND
rescans, verifies the backup file count matches, and refuses to delete
anything if it does not.
- It never reads, prints or copies a macaroon's CONTENT. Everything it
reports is a SHA-256 digest, so the material is proven changed without
disclosing it to the terminal or scrollback. lncli runs INSIDE the
container and reads the macaroon off its own disk, so the secret never
crosses into this script's output.
- It records the node identity pubkey and channel census BEFORE, and
aborts loudly if the identity or the OPEN channel total changed.
Two deliberate non-assertions, both of which would otherwise produce
frightening false alarms on a completely healthy rotation:
- wallet.db is NOT asserted byte-identical. btcwallet records chain sync
progress inside it, so it legitimately changes on every start.
- num_active_channels alone is NOT asserted. It counts channels whose
peer is currently online and so legitimately dips after any restart
while peers reconnect. The safety invariant is the ACTIVE+INACTIVE
total, which is what gets asserted; a changed active count is reported
as normal post-restart behaviour.
Enumeration runs under sudo rather than as a shell glob: the LND data
dir is 0700 owned by the container's mapped uid, so "$LND_DIR"/*.macaroon
does not expand in an unprivileged shell — it stays literal, which would
have made both the backup and the removal loop silent no-ops. Verified
on a live node: sudo find returns 9 files where the glob returns 0.
Exercised in detect mode against a real LND on a live node: correctly
reported the binary as unpatched, live-probed :18083 as LEAKING (200),
read both digests and the node identity, and exited 2 without changing
anything.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
