A server created through the panel never had RCON. CreateServer built a
MinecraftServerSpec without a Rcon block at all, so the field took its zero value
and every downstream consumer read Enabled=false. Nothing failed loudly: the
operator skips the probe when RCON is off and marks the server Ready on pod
readiness alone, so the panel showed "运行中" for a server the control plane could
not talk to. Everything that rides the write channel (spec §8 写=RCON) was dead —
the online-player list returned nothing because Status.Players is only ever
sampled by the probe, and console writes answered 503 ErrConsoleUnavailable
because internal/api/console.go refuses when Enabled is false.
The whole RCON machinery already existed — builders gate the service port,
container port, preStop save-and-stop hook and the RCON_* env on Spec.Rcon,
the reconciler probes and reports, console.go dials, the NetworkPolicy opens
25575 to {api, operator}. The only thing missing was that nobody ever turned it
on or created a password. This wires the three layers that were absent.
Provisioning lives in the operator, not in felis-api. felis-api holds secrets:get
and not create, and giving it create solely to mint a password it immediately
stops caring about (console.go re-reads the Secret at command time) would widen
the API's powers for nothing. The operator already reads every Secret in the
namespace, so adding create there grants no read it did not have. It also makes
provisioning declarative: a Secret deleted by hand comes back on the next pass, a
controller reference garbage-collects it with the server so no delete path has to
remember it, and a server that predates RCON only needs spec.rcon filled in for
the password to appear. The name comes from naming.RconSecretName so felis-api,
`felis setup` and the operator cannot drift apart on it.
RCON is enabled per system service rather than by default, because enabling it on
a backend that serves no RCON listener is destructive rather than merely useless:
the operator gates readiness on the probe, so such a server never leaves Starting
and is eventually marked Failed. The login limbo is exactly that backend
(LOOHP/Limbo has no RCON) and it is the front door, so it stays off; the lobby
runs Paper and is administered through the panel like any other server, so it is
on.
Paper only reads RCON settings from server.properties, so the operator's injected
RCON_PASSWORD did nothing on its own — felis-lobby's entrypoint now writes the
three keys on every boot. Rewriting them each time makes the copy in the world
volume derived state rather than the source of truth, so an owner who edits them
through the panel's file editor cannot lock the control plane out of their own
server. Without a password it sets enable-rcon=false and warns rather than
refusing to start: unlike the forwarding secret, a missing RCON password degrades
the server rather than making it unsafe.
That password landing in server.properties is a §286 exposure (RCON 密码绝不下发
前端), since server.properties is readable through the file editor. It is redacted
on read rather than the file being denied outright the way config/paper-global.yml
is: the forwarding secret is cluster-wide material that merely happens to sit in
the volume, whereas server.properties is the single most-edited config an owner
has, and hiding one line should not cost them MOTD, difficulty and view-distance.
The write path is deliberately left alone — the boot-time rewrite restores the
real value, which is what makes redacting rather than denying safe here.
Also guards idle auto-stop on Rcon.Enabled. Status.Players is only meaningful
when the probe ran; with RCON off it keeps its zero value, which that branch would
have read as "empty" and used to stop a server full of people. AutoStopEnabled is
not currently settable through any path, so this is a latent footgun rather than a
live bug, but it is one line and the alternative is discovering it in production.
Checks: the operator provisions a missing Secret with a 32-hex-char password and a
controller reference, and does not rotate an existing one; idle auto-stop stays
inert without RCON; the editor redacts rcon.password from the world root's
server.properties while leaving the rest of the file (and a plugin's own nested
copy) intact; login has RCON off and lobby has it on with the shared secret name;
CreateServer sets the block. That last one departs from K8sCluster being
integration-tested against a live cluster: this defect was a struct literal
missing a field, it shipped, and a fake client is enough to pin a struct literal.
Existing servers are NOT migrated by this change — CreateServer only covers new
ones and ensureSystemServers is create-if-absent, so a `felis setup` re-run will
not touch an existing lobby. A deployed install additionally needs the
felis-lobby image rebuilt and re-imported for the entrypoint change, and its pods
recreated, before the RCON keys reach server.properties.
Give an owner a way to repair the one failure no other endpoint covers: a
server that will not boot because a single line of server.properties or a
plugin's YAML is wrong. Until now that needed a human with cluster access.
felis-api cannot touch a world in-process — the world PVC is ReadWriteOnce
and its lifecycle belongs to the operator's StatefulSet — so the work runs
as a one-shot Job, and the server must be stopped first because a running
one holds the volume. That is the same constraint that shapes restore and
backup, and the handlers enforce the stopped gate the same way.
What is different is that the caller wants the OUTPUT, not just the side
effect. The Job prints its result to stdout and felis-api reads it back
through the pods/log subresource, which needs no permission felis-api does
not already hold: jobs:create, pods:list, pods/log:get. No pods/exec, no
pods/portforward, not even pods:get. The price is latency — every operation
is a Pod schedule — which is why this is a repair tool and not a file
manager.
Containment is structural, not textual. Every filesystem access goes through
os.Root, the stdlib's escape-proof directory handle, which resolves each
component against the open root descriptor and refuses "..", absolute paths,
and symlinks leading outside. The string-prefix check used elsewhere is not
reused here: it validates a path as text and then opens it as a path, and a
world directory holds attacker-influenced content, so a symlink swapped in
between those two steps is a live threat rather than a theoretical one.
os.Root has no such window because the check and the open are one operation.
The Job's isolation is a strict subset of a restore Pod's: the weak
felis-restore SA with its token auto-mount disabled, exactly one volume (the
world PVC, mounted read-only for list and read so two of the three
operations cannot mutate anything), no Secret, no ConfigMap, no database
URL, non-root with an fsGroup matching the operator's so a written file is
readable by the server that later mounts it, and backoffLimit 0 so a failed
write is never silently retried as a second write.
Two limits on the surface are worth stating plainly, because the mount is
the server's whole working directory rather than a config subtree:
* A write accepts arbitrary bytes at any path, so an owner can place a
loadable plugin jar. This is deliberate — it is what a hosting panel's
file manager does, scoped to a server the caller already owns and
already drives through /command — but it is the one owner-tier route
that lands executable code in a backend pod, since images are
admin-only and modpack submissions need an admin verdict.
* config/paper-global.yml is refused on read. felis-lobby's entrypoint
writes FELIS_FORWARDING_SECRET into it on every boot, and that value is
identical on every backend, so reading it from a server you own would
hand you the handshake key for everyone else's. It is the only path in
the mount that is not the caller's own data, and therefore the only
denial. The comparison is on the cleaned path, or ./config/... would
walk straight through it.
Writing that file is still allowed: it leaks nothing, and the entrypoint
rewrites it whole on every boot regardless.
The write body's content field is a *[]byte rather than a []byte for the
reason permissionRequest.Value is a *bool — a plain slice makes absent,
null, and empty indistinguishable, so a body of {} would decode to nil and
truncate the target to zero bytes while answering 200, destroying the very
config the caller opened the editor to repair.
Lemon-miaow
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