4 Commits
Author SHA1 Message Date
octoturge b4948076a0 Trade the gateway token for an edge JWT on every connection
Windows discovery tool / windows (push) Successful in 1m24s
The proxy put its configured gateway_token straight into the upgrade's
Authorization header, but the backend only accepts a one-hour edge JWT
(scope "edge") there, minted by POST /auth/edge-token from the farm's edge
proxy token. Nothing in the proxy ever made that call, so a gateway
configured with the token the console hands out could not connect at all,
and one given a hand-minted JWT (which is what every test did) would have
been locked out an hour later on its first reconnect.

Each connection attempt now starts by trading gateway_token for a fresh JWT,
at an address derived from the socket URL so there is one to configure. A
401 is reported as what it means (token rotated or wrong), since retrying
will not fix it. Config's Debug no longer prints the token.

tests/uplink_late_result.rs now plays the cloud's exchange endpoint and
asserts the socket opens with the minted JWT, not the configured token.
.env.example and continuum.example.toml say what the token is.
2026-10-29 15:10:27 +00:00
octoturge c6cf9bcb5e Report discovered printers to the cloud, off by default
The gateway could already find printers; only a human reading a terminal
could see the result. So adding a printer in the web console still began with
walking to a machine to read its IP address off the screen.

Now a background task scans on a timer and sends a `discovered_printers`
frame. It cannot finish the job - the credential is on that screen and no
probe can read it - but it removes the address, the serial and the guesswork
about which vendor the thing is.

OFF by default, which is the load-bearing part of this commit. A /24 sweep is
254 TLS handshakes and up to three HTTP requests per host, and nothing
watching can tell that from a port scan; on a corporate network, being
indistinguishable from a port scan is itself the problem. A gateway that did
this by default would scan networks its operator never meant to point it at,
and the first they would hear of it is from their own security team. So:

- `discovery.enabled` is false unless set, per gateway, in that gateway's own
  config. The cloud cannot switch it on. A setting whose whole purpose is to
  bound what this process does to the local network has to be decided where
  that network is understood, which is not in a data centre.
- `subnets` is explicit, never derived from this host's interfaces, so a
  second NIC, a VPN or a container bridge cannot widen the sweep. Anything
  wider than a /24 is still refused, now at config-import time rather than
  when the timer first fires.
- A flag that is neither `true` nor `false` is an error, not a shrug. The two
  readings of a typo are not equally safe.
- Naming a subnet without setting `enabled` scans nothing - the safe reading
  of an incomplete instruction - and `enabled` with nowhere to look is
  refused as the mistake it is.
- The env var can switch it *off* over a file that enables it, which is the
  direction that has to work: a Proxy Box's config is signed in the cloud, so
  an operator who finds their gateway probing cannot just edit it.

What a scheduled scan will not do, unlike the example CLI: send `M115`.
Opening a serial port toggles DTR, which reboots an Arduino-based board and
ruins a print in progress. The example can do it behind
`--yes-reset-the-printer` because a human is standing there; a timer has
nobody to ask, so it does not get the option and reads sysfs instead.

Two things that took more care than expected:

`Scan::looked()`. An empty report means "this gateway looked and its network
has no unconfigured printers", so sending one after every probe failed would
state something untrue about the farm. A partial failure is still evidence,
though - withholding a good sweep because a container can never bind SSDP
would suppress it forever - so the test is "did anything succeed", not "did
everything".

`fleet::configured()` reads the fleet file at parse level rather than through
`load`, because the entry it most needs to recognise is the one `load`
refuses: a printer discovery suggested, pasted in, with the access code not
yet typed in. Re-offering that printer as a fresh find is noise at the one
moment the operator is mid-way through adding it.

Verified against the real LAN: a sweep found both printers by TLS certificate
with correct serials and no credentials, and the frame it produced validates
against the backend's EdgeClientMessageSchema. The `wire` subcommand on the
example prints exactly that frame, and the capture is pinned as a backend
fixture. SSDP remains untestable here - this container is a router hop from
the printers and multicast does not cross one.
2026-10-19 08:21:30 +00:00
octoturge 1cd8ce25c3 Authenticate config bundles: Ed25519, per-box identity, no plaintext
The hash in a bundle only proved it was undamaged. Anyone who could write
the stick could write both files, so a Proxy Box would install a config
handed to it by whoever got physical access - including a config pointing the
box at a different cloud.

Encryption alone does not fix that either. While plaintext was accepted an
attacker simply did not encrypt, and the box took it. So a Box now refuses
plaintext outright, and the bundle carries a signature.

A third entry, `config.toml.sig`: strict TOML with `box_id`, `config_version`
and a raw Ed25519 signature. What is signed is `signed_message()` - a domain
tag, the length-prefixed box id, the version big-endian, then the raw
`config.toml` bytes. Raw bytes rather than the archive, so the signature is
independent of ZIP framing, compression, entry order and encryption. The box
id and version are inside the signed message rather than beside it, so
neither can be edited without breaking it, and the length prefix stops a
byte-shifting collision between the id and the config.

Past decryption the order is hash, signature, box id, version, then parse and
validate. The claims in the `.sig` are attacker-controlled text until the
signature over them verifies, so nothing is concluded from them before then -
and nothing about this box's identity is revealed before then either, which
is why unsigned junk cannot be used to probe which box it is talking to.

Which error wins when a box cannot even open a bundle: a signature over the
plaintext is only checkable after decryption, so a box with the wrong key
cannot distinguish "meant for another box" from "forged". Wrong key wins.
Neither bundle installs either way, it is nearly always the true cause, and
calling something forged that we could not open would be an accusation we
cannot support.

Replay is enforced rather than documented away: `config_version` must not go
backwards, recorded in a sidecar beside the installed config. An equal
version is accepted on purpose, because the version is written before the
config, so a power cut between the two leaves "new version, old config" and
re-inserting the same stick repairs it. The other write order would leave a
replay window instead.

Both key sets are lists, so the cloud's signing key and a box's own key can
be rotated. `load_provisioning()` is the single seam where a box's identity
and keys come from; a TPM or secure element replaces that function and
nothing else. A missing file means unprovisioned, and the box then says
loudly what it cannot check - but an empty or malformed one is an error,
because quietly reading a broken key file as absent would turn a
provisioning mistake into a box that accepts unsigned bundles.

Not verified: interop with the real cloud signer. These tests prove the box
accepts what this code defines as correct, not that the cloud will produce
the same bytes - the message layout, the pure-Ed25519-no-prehash choice and
the `.sig` shape all need a cross-check against the configurator's own crypto
library once it exists. A compromised cloud signing key still breaks every
box trusting it; revocation is not built.
2026-10-19 08:08:27 +00:00
octoturge 64d46dbc49 Load proxy settings from a file, and import them from a pendrive
Everything came from CONTINUUM_* environment variables, which suits neither
shape the product ships in. A Proxy Box is an appliance whose settings
arrive on a USB stick; a proxy on someone's PC is a config file they edit.

Precedence is stated once, in config.rs: the file is the base, env overrides
it, defaults fill the rest. `Config::from_env` keeps its behaviour and the
struct is unchanged, so existing callers and tests are untouched. Layering
is `Config::layered(file, env_lookup)` with the environment injected as a
closure, so tests do not have to mutate process env to cover it.

The bootstrap is read from $CONTINUUM_BOOTSTRAP, then
/etc/continuum/bootstrap.toml, then nowhere - and nowhere means PC mode with
./continuum.toml, so an env-only deployment behaves exactly as before. The
working directory is deliberately not searched, and the bootstrap itself
must never come from a stick: it is what says whether sticks are trusted at
all.

Bundle format is continuum-config.zip holding config.toml and
config.toml.sha256. The hash is checked before the bytes are parsed - the
TOML parser should not be the first thing to read possibly-corrupt input -
and **the comments say plainly what that buys: corruption and change, not
forgery.** Anyone who can write the stick writes both files. It is an
integrity check under a recorded trust assumption, that physical access to
the box is trusted; a signature with the key in the box image is named as
the follow-up that would give authenticity. sha256 via openssl, already a
direct dependency, so no new crate and `cargo deny check licenses` still
passes.

The hazards of ingesting a file off removable media, all tested:

Zip-slip is refused on absolute paths, `..` components, backslash
separators, drive prefixes, NUL and non-UTF-8 names, and one bad entry
rejects the whole bundle rather than being skipped. The stronger guarantee
is structural though: entries are only ever read **by index, matched against
two literal names**, and no write path is ever derived from an archive name,
so a hole in the name check still writes nothing. A test confirms a bundle
carrying `../evil.toml` alongside a valid config writes nothing outside the
target and leaves the installed config alone.

Zip bombs are capped at 16 entries, 256 KiB per entry and a 1 MiB file on
the stick. Declared sizes are refused in a first pass that decompresses
nothing, and a bounded reader then caps actual output so a lying header
gains nothing.

Installing is atomic: temp file in the destination directory - not /tmp,
since rename is only atomic within a filesystem - created 0600 from the
first byte because the config holds the gateway token, fsync, rename, then a
best-effort directory fsync. A write that fails halfway leaves the previous
config intact and no temp file behind.

A bad stick never costs the box its config: a bad hash, bad TOML, an unsafe
entry or missing settings all return Rejected and are logged as keeping the
existing config. A correctly-hashed config is also validated **with no
environment at all**, so a stick cannot install something that parses now
and fails to start on the next boot - which would be a bricked box caused by
exactly the stick we were being careful about.

PC mode ignores pendrives twice over, by mode and by an emptied directory
list, because on a general-purpose machine importing settings from a USB
stick would be a way to change them behind the user's back.

A [network] block is parsed, validated and exposed, and stops there. main.rs
logs a warning that this build does not apply it, so a box given network
settings cannot look like it acted on them. Applying them needs root, is
specific to the appliance image, and a wrong write strands the box - it wants
its own decision, not a side effect of reading a file.

continuum.toml is gitignored, since it holds the gateway token.

Not done, and not claimed: no signature, so no authenticity. There is no real
pendrive here, so the removable-media path was tested with ordinary
directories standing in for mount points - real udisks/udev mounts, FAT
behaviour, a genuinely yanked stick and how promptly the 5s poll notices a
mount are all unproven. The watcher's install-then-exit flow, which relies
on a supervisor restarting the process, has no test and no supervisor exists
in this environment; a stick left permanently inserted reports Unchanged
rather than looping, because the hash matches. Env still overrides on a box,
so a box is only pendrive-only to the extent its environment is trusted -
bootstrap.rs says so.
2026-10-19 07:49:46 +00:00