felis nano serves the same hasJoined handler as felis api, but behind
nanoStubRepo, which implements only the bar-list lookup and embeds a nil
Repo for everything else. Only the full-api path was tested, against a
complete fake store, so a second store call added to handleHasJoined
would pass CI and panic on every nano login. The loopback default of
-listen, the one thing keeping nano from being an open auth relay, was
not pinned either.
The default moves into a nanoDefaultListen constant, and two tests
cover the path. One serves a login through api.HasJoinedHandler with
nanoStubRepo and a fake identity source and expects the profile back.
The other requires the default to parse as a loopback IP. Taking the
bar-list method off the stub makes the first panic on the nil Repo;
defaulting to 0.0.0.0:8081 or :8081 fails the second.
LoadNano filled in [server] listen = "0.0.0.0:8080" when it was unset,
and a test pinned that value, but felis nano never reads it: it binds
the -listen flag, which the installer sets from FELIS_NANO_LISTEN. An
operator moving nano off loopback by writing [server] listen in its
config got connection refused from the proxy and no hint that the key
did nothing.
LoadNano no longer sets the default, and nano prints a line naming the
ignored value and the address it actually binds whenever the key is
set. It is a warning rather than a load error so a full felis.toml
copied onto a nano host keeps starting. The assertion that pinned the
unused default is removed along with it.
The new test runs cmdNano against a config that sets [server] listen
and one that does not, with an unbindable -listen so it returns after
loading. The first must warn and the second must not; with the old
default restored, the second prints a warning about 0.0.0.0:8080.
The installer and the config template tell the operator to run
systemctl restart felis-nano after editing the source list. nano had no
signal handling, so SIGTERM killed it mid-request: a login waiting on an
upstream had its connection reset, and Velocity disconnected that
player with "authentication servers are down". felis api already drains
on shutdown; nano did not.
nano now listens itself, serves until SIGINT or SIGTERM, then shuts the
server down gracefully with a 30-second limit. That outlasts the source
scan of any realistic list, at five seconds per source, and stays well
inside systemd's default 90-second stop timeout.
The new test holds a request inside the handler, cancels the serve
context, and checks that serveNano is still running 200 ms later, that
the held request then gets its answer, and that serveNano returns 0.
Replacing the graceful shutdown with Close fails it.
felis nano logged every request with the raw RequestURI and %s. That
text is the caller's: a right-to-left override reordered the line as
displayed, an invalid UTF-8 byte made journald store the entry as a
binary blob that journalctl -f shows as "[N blob data]", and a query
near net/http's one-megabyte limit became a one-megabyte log line.
The URI is now capped at 256 bytes, several times a real hasJoined
query, and printed with %q, so control, bidi and invalid bytes appear
escaped. The handler assembly moved into nanoHandler so the logged
handler can be tested on its own; cmdNano serves it unchanged.
The new test sends a query carrying U+202E, a 0x9b byte and 4 KiB of
padding, and expects a valid UTF-8 line with the override escaped and
no more than twice the cap. Restoring the old unquoted line fails it.
Seventeen comments opened with a tag naming the tool that wrote them.
The tag goes and each comment keeps its reasoning, now starting as a
plain sentence. None of the reasoning changes.
The AGENTS.md note in .gitignore drops the story of how the file got
into the tree and keeps the one fact a reader needs: its advice to run
go fmt is destructive on this CRLF working tree.
Comments only; no code, build or test changes.
nano.go's package comment told the reader that `felis setup --nano` installs the
multiplexer as a service. No such flag has ever existed -- `felis setup` defines
only -config and -dev -- so anyone following the comment gets "flag provided but
not defined: -nano" and exit 2.
Adding the flag was the obvious reading, and it is the wrong one. setup does not
install anything selectively: it re-images the host by running the full bootstrap
TUI, and no install-mode parameter is threaded anywhere -- nothing in Go reads or
writes FELIS_INSTALL_MODE, which is a shell variable bootstrap.sh consumes on its
own. So `--nano` could only mean one of two things. Re-run the installer in nano
mode, which is what pointing at the installer already does. Or convert a
provisioned full host into a nano one, which means tearing down k3s, Postgres and
the proxy -- an uninstall, not a flag.
setup's --dev already settled this shape once. It looked like a channel selector,
silently installed release, and the fix was to refuse it and name the installer
rather than pretend to choose. The same answer applies here, so the comment now
names the real entry point -- the installer's `[2] Felis-nano` prompt, or
FELIS_INSTALL_MODE=nano -- and records why there is no flag, so the next reader
does not reopen it.
No refusing --nano flag is added: --dev exists because it used to be a silent
no-op that people passed, and nothing has ever accepted --nano, so flag's own
"not defined" error is already the correct and clearer failure.
d417efc got this backwards, in both the code comment and the installer summary.
It claimed authlib appends /session/minecraft/hasJoined itself, so the property
should be given the base URL only. Velocity does not work that way, and a real
login says so: pointed at http://127.0.0.1:8081, a Mojang login arrives at nano
as
GET /?username=FLYEMOJ1&serverId=-23ae0b50...
with no path at all. Velocity appends the query string to the property verbatim
and issues the request itself; authlib is not in the loop. nano has no route on
/, so it answers 404 and Velocity kicks the player with authservers_down.
Velocity's own default for the property is the full URL,
https://sessionserver.mojang.com/session/minecraft/hasJoined, which is the same
thing said another way.
With the full endpoint URL the same account logs straight in, so both the
nano.go header and summary_nano now print
-Dmojang.sessionserver=http://127.0.0.1:8081/session/minecraft/hasJoined
and note that the flag belongs between `java` and `-jar`.
Verified against Velocity 3.5.1 + Paper 26.2 on the deploy host: a Mojang login
reaches the backend with its real Mojang UUID unchanged, and a LittleSkin login
under the same username reaches it as UUIDv3(felisAuthNS, "littleskin:"+id) --
two different players on the backend, which is the point.
Deploying `felis nano` to a real Rocky Linux 10 host surfaced four defects that
no local check could see. Fixed together because they all sit on the same path
from `curl|bash` to a running felis-nano.service.
* docker killed the nano install on EL10. `acquire_nano_binary` pulled in
docker purely to build the binary; on Rocky 10.2 the docker-ce el10 rpms
install but dockerd refuses to start, so the install died at
`systemctl enable --now docker`. nano needs one static binary, not an image,
so the docker dependency is gone: fetch_source -> install_go_toolchain
(pinned FELIS_GO_VERSION, default 1.26.4, amd64/arm64) -> build_nano_binary.
* the built binary could not be exec'd by systemd (203/EXEC). The Go linker
renames its output out of $TMPDIR, and a same-filesystem rename carries the
source SELinux label, so `go build -o /usr/local/bin/felis` produced a binary
labelled user_tmp_t rather than bin_t. root is unconfined and could run it by
hand, which is what made this look fine, but the DynamicUser service could
not. build_nano_binary now stages the output and installs it as a fresh file
so the policy type transition labels it bin_t, with restorecon as a belt.
* re-running the installer did not converge. `systemctl enable --now` is a
no-op on an already-active unit, so a rebuilt binary was installed while the
old process kept running. Now enable + restart.
* the Velocity wiring comment in cmd/felis/nano.go was wrong. authlib appends
/session/minecraft/hasJoined itself, so -Dmojang.sessionserver takes the base
URL only, as the installer has always printed.
Also bind to loopback by default. hasJoined is unauthenticated by protocol --
authlib speaks the vanilla sessionserver dialect and sends no token -- so a
public bind is an open auth relay: anyone can point their own proxy at it and
spend this host's egress IP on Mojang until Mojang rate-limits it and the
operator's own players stop getting in. It is not an identity bypass (a caller
still needs a serverId hash bound to their own server key, which the upstream
Yggdrasil validates), but it is someone else's traffic on your address.
FELIS_NANO_LISTEN and the -listen flag now default to 127.0.0.1:8081, which a
same-host Velocity reaches unchanged; serving an off-host proxy is an explicit
opt-in. configure_nano_firewall no longer opens a port for a loopback bind, and
summary_nano prints the real bind address plus the relay warning.
Verified on the target host: installs with no docker present, service active,
binary labelled bin_t, `ss` shows LISTEN 127.0.0.1:8081, an external request is
unreachable, and an in-host request returns 204 with the login logged.
BREAKING CHANGE: felis nano defaults to 127.0.0.1:8081 instead of 0.0.0.0:8081.
A Velocity proxy on another machine must now set FELIS_NANO_LISTEN (or -listen)
to a reachable address, and should allow that port only from the proxy's IP.
`felis nano` serves the vanilla sessionserver protocol
(GET /session/minecraft/hasJoined) as a federating multiplexer over
Mojang plus any number of third-party Yggdrasil roots, with no k3s,
Postgres, or panel — a MultiLogin-style auth front-end delivered as a
subcommand of the single felis binary rather than a separate build.
- config.LoadNano reads only [[auth_source]] blocks; it skips the
database.url / root_domain / archive requirements the full server
needs. Zero sources is valid (Mojang-only).
- Mojang is prepended in code (Identity:true), never from config, so it
is always the sole identity root. Third-party profiles are rewritten
to canonical = UUIDv3(felisAuthNS, tag+":"+nativeID).
- validateAuthSources rejects unknown keys, duplicate tags, and
scheme-less URLs — a malformed nano config fails loud at load.
- Reuses api.HasJoinedHandler with a stub Repo (no blacklist backend);
a rejected login is a 204, matching the vanilla sessionserver.
- nano.go binds the -listen flag and ignores [server] listen in config.
Verified on WSL (go1.26.4): go build/vet/test ./... green; a runtime
smoke against the template config returns 204 on a miss and logs
"Mojang + 0 third-party source(s)"; a duplicate-tag config exits
non-zero citing "unique".
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