CB-633: constrain a member's environment with a real allow-list (memberCredentials.policy) #147

Merged
ltms merged 2 commits from worker/cb-633-env-allowlist-31c312-8 into main 2026-08-23 08:22:06 +02:00

2 Commits

Author SHA1 Message Date
Dai Ha 6f968d59a4 CB-633 round 2: the scrub ran on macOS and did nothing on Linux
CI / build (pull_request) Failing after 1m8s
CI / contract (pull_request) Successful in 1m10s
Six review findings, from the peer lead `vms` and a reviewer worker. The first
one is a real defect that would have shipped as a dead control.

1. The scrub only ran in a login shell. It lived in the generated `.zlogin`,
   and zsh reads `.zlogin` only for a login shell. herdr does not open the same
   kind of shell everywhere: measured on herdr 0.8.0, a macOS pane runs `-zsh`
   (login) while a Linux pane runs a plain `/usr/bin/zsh`. So on the vhost this
   was being built for, `.zlogin` never ran and every member kept the whole
   secret store, in silence.

   The scrub body now lives in a generated `scrub.zsh` that BOTH `.zshrc` and
   `.zlogin` source, each after sourcing its own `$HOME` counterpart. Linux
   runs the first, macOS runs both, and the second pass is not merely harmless
   -- it re-scrubs anything the operator's `~/.zlogin` exported after `~/.zshrc`
   had finished. Re-running is idempotent.

2. `INFRASTRUCTURE_PASSTHROUGH` listed names that are not infrastructure:
   ANTHROPIC_AUTH_TOKEN, GITEA_TOKEN, GITEA_HOST, ANTHROPIC_BASE_URL,
   ANTHROPIC_MODEL, CLAUDE_CONFIG_DIR, OPENCODE_CONFIG, BRIDGED_MEMBER. I read
   each injection point and confirmed every one of them reaches `launch.env()`
   only when actually injected, so `allowed.addAll(launch.env().keySet())`
   already covers the legitimate case. As static entries they were pure leak
   surface: a host that happened to export ANTHROPIC_AUTH_TOKEN would have had
   it passed straight through.

3. A missing `scrub-report.txt` at teardown was logged at debug. The report is
   the only evidence the scrub ran at all. Its absence has an innocent reading
   and a serious one, and we cannot tell them apart from the daemon -- so it is
   now a WARN that says exactly that. Logging it at debug is how a control that
   quietly stopped working stays unnoticed.

4. Nothing tested that the control was wired in. Deleting the single
   `applyEnvironmentAllowListPolicy(cfg, launch)` line left all 896 tests green
   while turning the feature completely off -- the CB-586/CB-611 shape again.
   `HerdrPeerLauncherAllowListWiringTest` starts a real spawn and asserts on the
   env that reached herdr. Mutation-checked: unwiring that line fails it.

5. `EnvAllowListScrubTest` now also runs `zsh -i` with no `-l`, which is the
   Linux pane shape, so finding 1 is tested from a Mac. Mutation-checked:
   putting the scrub back in `.zlogin` alone fails that test alone, while the
   login-shell test still passes -- which is exactly the blind spot that let
   the bug through.

6. Two ZDOTDIR leaks closed. A failed spawn has no pane id, so its directory
   was never keyed for teardown; it is now removed on the way out. And
   `deleteOnExit` covers a clean shutdown and nothing else, so `generate` now
   reaps sibling directories older than 24h left by a killed daemon.

Also: `policy:` is lowercased with Locale.ROOT, and the `.zlogin`-only claim is
corrected in fleetd.example.yaml, FleetConfig and HerdrPeerLauncher.

901 tests, 0 failures, `mvn clean install` green.
2026-08-23 08:17:52 +02:00
Dai Ha d432df8e5c CB-633: memberCredentials policy=allow-list — derived ZDOTDIR env scrub
CI / build (pull_request) Failing after 1m4s
CI / contract (pull_request) Successful in 1m19s
Move member environment control out of the pane-creation env overlay
(defeated by any file the login shell sources) into a per-spawn ZDOTDIR
directory whose .zlogin runs LAST, after the operator's whole chain, and
blanks every exported variable not on an allow-list DERIVED from what the
launcher itself injects (profiles' tokenEnv/gitTokenEnv/gitHostEnv/env
keys + an infrastructure set) — never hand-typed.

- memberCredentials.policy: allow-list (deny-by-default/deny-list stay
  default and unchanged); known:/allow: become reporting only under it.
- memberCredentials.sshAuthSock knob, blocked by default; allowing it is
  an explicit decision (operator ssh-agent handle).
- Non-zsh login shell: loud WARN, protection off, fallback to the old
  enumerated-name overlay.
- Scrub writes an 'allowed N of M' denominator report, read at teardown;
  credential-shaped blanked names go to WARN (names only, never values).
- Equality test against a real login zsh from a clean parent: surviving
  non-empty exports EQUAL baseline ∩ derived allow-list.
2026-08-23 07:43:38 +02:00