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3 Commits
Author SHA1 Message Date
KRATOS fbbfdbf3f2 Harden background daemon: stdout integrity, lifecycle, and single-instance lock (#274)
* harden background daemon: stdout integrity, lifecycle, single-instance lock

Deep review of internal/daemon (worker pool, launcher, control server,
session fan-out, single-instance lock) found and fixes a stdout-integrity
bug plus several lifecycle/locking hazards. Each fix has a regression test;
the daemon suite passes under -race.

Worker stdout integrity
- Replace the capped bufio.Scanner (64 KiB) on a worker's stdout with an
  uncapped bufio.Reader: a legitimately large stream-json line from our own
  trusted worker is no longer silently dropped (the 1 MiB cap belongs to
  untrusted network frames, not this local pipe).
- Surface a stdout read error as a run failure instead of swallowing it as a
  clean success, and kill the worker first so it can't block writing to the
  now-unread pipe and hang Wait.

Control-server lifecycle
- Track open connections and close them on Shutdown so a single idle/hostile
  client can no longer wedge drain (and SIGTERM cleanup) forever.
- Guard the listener with a mutex and re-check the shutdown signal after bind
  so a shutdown requested in the bind window is not lost.
- Honor shutdown during buffered-history replay too.

Session fan-out
- A slow subscriber that drops live lines now receives a namespaced gap
  notice when its channel drains, instead of silently losing output.
- Hold the session lock across the (non-blocking) broadcast sends to close a
  latent send-on-closed-channel panic when a subscriber cancels mid-send.

Single-instance lock
- Reclaim a stale lock with an atomic rename-with-verify instead of a blind
  remove, so two instances starting at once cannot both reclaim and end up
  both holding the lock; a holder that reacquires in the gap is restored.

Client + pool
- Bound the control handshake with an I/O deadline so a peer that never
  replies can't wedge Dial/NewClientConn.
- Key the active-worker map by a monotonic id rather than PID (the OS reuses
  PIDs the instant a worker exits).
- Group-terminate on context cancel so a stuck worker's children are not
  orphaned.

* daemon: add -race regression test for the Session.Line lock-hold invariant

Session.Line holds s.mu across its non-blocking subscriber sends so cancel()/
finish() cannot close a subscriber channel mid-send (send-on-closed-channel
panic). That invariant had no concurrency test. Add one that drives Line
concurrently with Subscribe/cancel and finish; it panics with a data race if
the lock-hold is reverted and passes with it (verified both ways under -race).
2026-06-20 22:21:28 +05:30
KRATOS f857c4afb4 feat(daemon): TLS remote bridge — authenticated network access to the daemon (#211)
* feat(daemon): TLS remote bridge — authenticated network access to the daemon

Add internal/daemon/remote: an OPT-IN, TLS-only network bridge on top of the
local daemon. A remote client drives the SAME SessionManager/Pool over the
network behind bearer-token auth, reusing the daemon's framing and dispatch
unchanged. The local Unix-socket daemon stays the default and is unchanged.

- Bridge: per accepted TLS connection, authenticate THEN hand to the daemon's
  control dispatch via the new Server.ServeConn seam — a remote session runs
  under the same sandbox/risk model as a local one (never bypasses it).
- Authenticator + TokenAuthenticator: constant-time bearer-token check, token
  from $ZERO_DAEMON_REMOTE_TOKEN or a file; optional attestation hook (no-op
  default). Auth happens before any control frame; failure closes the connection
  after a small backoff; tokens are never logged.
- RemoteClient (DialRemote): verified TLS dial (never InsecureSkipVerify) + auth
  handshake, then the existing daemon.Client via the new NewClientConn seam, so
  remote and local share one protocol.
- Fail-closed: TLS mandatory (refuses without cert/key), a configurable
  min-protocol-version floor, the 1 MiB frame cap reused, and a bounded
  concurrent-connection cap that refuses overflow.
- CLI: `zero daemon serve-remote --addr --tls-cert --tls-key`; `run`/`attach`
  gain `--remote <addr> [--token --ca-cert --server-name]`.

Daemon seams added (additive, behavior unchanged): Server.ServeConn,
NewClientConn. SessionLink (event POST) and git-bundle repo transfer are
documented follow-ups.

Tests cover auth accept/reject (env + file), TLS-required, cert verification,
version floor, run/status/attach round-trip, re-attach resumption, connection
cap, and ListenAndServeTLS/Close. Gates: gofmt / vet / build (host+linux+
windows) / test -race / staticcheck (no new) / govulncheck (0) / deadcode
(no new) all pass.

* swarm: de-flake TestMailboxConcurrentSends on Windows CI

The 200-way concurrent-send stress test inherited from the swarm package timed
out on Windows CI (103/200 sends hit the 10s lock timeout): the lock's 20ms
retry sleep starves waiters when Windows file ops are slow under heavy
contention. Shorten the retry to 2ms (a freed lock is re-acquired promptly) and
raise the test's lock timeout to 60s so a legitimately-slow CI never times a send
out. Passes repeatedly under -race. (CI de-flake of a test that surfaced on
#210's Windows smoke; functionally unrelated to the OAuth changes.)

* remote: address CodeRabbit re-review (TLS dial + Close idempotency)

- client: replace the deprecated, non-cancellation-aware tls.DialWithDialer with
  a context-aware tls.Dialer.DialContext (resolves the golangci-lint noctx CI
  blocker; the context bounds the dial + TLS handshake).
- bridge: Close now clears b.listener under the lock, so a repeat Close is a
  no-op instead of returning a closed-listener error (matches its doc). Test
  asserts a double Close succeeds.

Gates: gofmt/vet/build(host+linux+windows)/test -race/staticcheck(no new)/
govulncheck(0)/deadcode(no new) all pass.
2026-06-15 18:48:07 +05:30
KRATOS 135e3c5657 feat(daemon): zero daemon — worker pool + session supervisor over a local control socket (#203)
* feat(daemon): add `zero daemon` — worker pool + session supervisor over a local control socket

Adds internal/daemon + `zero daemon start|stop|status|run|attach`: a long-running
local service that supervises a pool of headless `zero exec` workers and routes
multiple agent sessions to them over an owner-only Unix-domain control socket.
Additive — interactive and one-shot exec are unchanged.

Reuses zero's building blocks:
- internal/background: ConfigureChildProcessGroup (process-group setup) +
  TerminateProcess (cross-platform terminate) for worker kill/drain. The pool
  does its own os/exec and uses background only for those helpers.
- internal/streamjson: the worker speaks stream-json on stdout; the daemon
  forwards those lines to clients.
- internal/cli exec: a worker is `zero exec --output-format stream-json`.

Pieces (reimplemented in Go from a reference daemon):
- protocol.go: framed control codec — 4-byte BE length + 1 kind byte, 1 MiB cap,
  JSON control messages, version negotiation.
- pool.go + backoff.go: bounded worker pool — at-least-once dispatch with
  exponential backoff+jitter retry capped by MaxAttempts, EXIT_TEMPFAIL(75)/
  EXIT_PERMANENT(76) handling, graceful drain + kill-timeout. zero's exec is
  one-shot, so workers are on-demand (one session per worker = the lease), not
  warm long-lived slots (a persistent worker mode is a follow-up).
- session.go: SessionManager — sessionID->worker routing, lease (one active
  request per worker), queue when the pool is full, per-session output buffer for
  attach + metrics.
- server.go + lock.go + socket.go + paths.go: single-instance PID-file lock with
  stale-lock (dead-PID) recovery, status file, owner-only socket, accept loop;
  cleans up lock/socket/status on exit.
- launcher.go: production worker launcher. client.go: control-socket client.

Security model:
- Control socket is LOCAL-ONLY (AF_UNIX loopback file, never a TCP port) and
  owner-only: socket 0600 + parent dir 0700 on POSIX (Windows relies on the
  per-user profile ACL; a dedicated pipe ACL is a follow-up).
- Workers stay sandboxed: the launcher SCRUBS the sandbox re-entrancy markers
  (ZERO_SANDBOXED / ZERO_SANDBOX_BACKEND) from each worker's env so the worker
  re-establishes its OWN sandbox instead of inheriting a pass-through plan, while
  propagating the rest of the policy config/env. The daemon never bypasses the
  sandbox.
- Control frames over the 1 MiB cap are rejected before allocation.

Robustness: a crashed worker never takes down the daemon (backoff+jitter retry,
MaxAttempts cap, EXIT_PERMANENT stops retry); drain gives a grace window then
force-kills stragglers; a stale lock from an unclean exit is reclaimed.

Out of scope (follow-up): remote session-linking; warm pre-spawned persistent
workers; Windows named-pipe ACL.

Tests: protocol round-trip + oversize/unknown-kind rejection; backoff bounds;
pool spawn/retry-backoff/permanent/cap/queue/drain; session lease/route/queue/
attach; lock single-instance + stale recovery; launcher env-scrub (incl. an
end-to-end check that the spawned worker process receives scrubbed env); server
e2e start->run->stream-json->status->attach->stop with a fake worker; CLI
usage/validation/not-running paths. Live-verified start/status/stop (0600 socket,
0700 dir, file cleanup). Platform files behind explicit //go:build tags.

* daemon: address review — help listing, extra-arg rejection, lock write error, bounded sessions

- cli/app.go: list `daemon` in `zero --help` so the command is discoverable.
- cli/daemon: `stop`/`status` reject extra arguments; `attach` rejects more than
  one session id (fail fast on typos instead of silently ignoring tokens).
- daemon/lock: check the PID fmt.Fprintf error — a partial/failed write would
  leave a malformed lock file that another process reads as stale and wrongly
  reclaims, breaking the single-instance guarantee; on write failure remove the
  file and return the error.
- daemon/session: bound the registry with MaxSessions (default 256) — evict the
  oldest FINISHED sessions once past the cap so a long-running daemon doesn't
  accumulate sessions without limit; running/queued sessions are never evicted, so
  attach-after-finish for recent sessions is preserved.

Tests: CLI extra-arg rejection; finished-over-cap eviction + running-never-evicted.
Gates: gofmt, vet, build, test (incl -race), staticcheck (no new), govulncheck (0),
deadcode (no new), GOOS=linux+windows cross-compile.
2026-06-14 22:16:37 +05:30