Investigate StrictModes dial-in denial on container 646

- No hatch user exists; dial-in identity is root (pubkey-only)
- Root auth path is StrictModes-clean; /home/hatch not consulted
- Empirical: root dial-in on VM:2226 SUCCEEDED with /home/hatch
  still group-writable -- neither chmod g-w nor StrictModes no needed
- Flagged: super@bl key only in /home/hatch/.ssh (never read by sshd)

Fixes #215

bin/verify-node-ssh.sh

@@ -0,0 +1,60 @@
+#!/bin/bash
+# verify-node-ssh.sh — verify container SSH dial-in readiness across fleet nodes.
+# Checks from the VM: reverse-tunnel listeners + SSH auth for each node port.
+#
+# Port map (docs/OPERATOR-DRIVE-RUNBOOK.md):
+#   muse-main 2224 | muse 2225 | 646 2226 | pip 2227 | opm 2228 | def 2229 | dev 2230
+#
+# What it checks per node:
+#   1. Reverse-tunnel listener on 127.0.0.1:<port> (dark node = no listener)
+#   2. SSH dial-in with BatchMode (auth failure = authorized_keys perms/key issue)
+#
+# Common root causes (see #211):
+#   - sshd requires non-group-writable authorized_keys (must be 600)
+#   - stale /run/nologin blocks logins
+#   - missing id_frontdoor keys on dark nodes
+#
+# Usage: run on the VM (super@34.139.37.135), or via:
+#   ssh-vm.sh "bash -s" < verify-node-ssh.sh
+set -u
+
+# node:port pairs to check
+NODES="muse:2225 646:2226 pip:2227 def:2229 dev:2230 muse-main:2224 opm:2228"
+
+fail=0
+for pair in $NODES; do
+    node="${pair%%:*}"
+    port="${pair##*:}"
+
+    # 1. listener check
+    if ss -tln 2>/dev/null | grep -q "127.0.0.1:${port} "; then
+        listener="LISTEN"
+    else
+        listener="DARK (no listener)"
+    fi
+
+    # 2. auth check (only if listening)
+    if [ "$listener" = "LISTEN" ]; then
+        out=$(timeout 15 ssh -o StrictHostKeyChecking=no -o BatchMode=yes \
+            -o ConnectTimeout=10 -p "$port" hatch@127.0.0.1 'echo OK' 2>&1)
+        case "$out" in
+            OK)            auth="OK" ;;
+            *"Permission denied"*) auth="AUTH-FAIL (check authorized_keys perms/keys)" ;;
+            *"Connection refused"*) auth="REFUSED (tunnel died after listen check)" ;;
+            *)             auth="OTHER: $(echo "$out" | head -1 | cut -c1-60)" ;;
+        esac
+    else
+        auth="SKIP"
+    fi
+
+    printf '%-10s port %-5s listener: %-22s auth: %s\n' "$node" "$port" "$listener" "$auth"
+    [ "$listener" = "DARK (no listener)" ] && fail=1
+    case "$auth" in AUTH-FAIL*) fail=1 ;; esac
+done
+
+if [ "$fail" -eq 0 ]; then
+    echo "ALL NODES REACHABLE"
+else
+    echo "ISSUES FOUND (see above)"
+fi
+exit "$fail"

cloud-uptime/uptime-watcher.sh

@@ -0,0 +1,130 @@
+#!/usr/bin/env bash
+# uptime-watcher.sh — simple hatch-hook watcher: spawn/rebuild from spec.
+#
+# Register as a hatch hook (id `uptime-watcher`, poll 120s, timeout 300s)
+# alongside tunnel-keeper. Each poll it guarantees the three things a
+# container rebuild destroys:
+#   1. provisioning  — runs recover-after-rebuild.sh on a fresh root fs
+#   2. supervisor    — respawns gcp-tunnel-up.sh if it died
+#   3. cron jobs     — reinstalls crontab from ~/workspace/cron/*.persist
+#
+# It also verifies the VM-side SSH forward answers a banner, and wakes the
+# operator (rate-limited, 30 min) only when something stays broken across
+# polls. Silent on success. Safe to run by hand or from cron too.
+set -u
+
+# --- runtime (hatch hook functions, or local fallbacks) ---
+if [ -n "${HATCH_HOOK_RUNTIME:-}" ] && [ -f "$HATCH_HOOK_RUNTIME" ]; then
+    # shellcheck disable=SC1090
+    source "$HATCH_HOOK_RUNTIME"
+else
+    log() { echo "[uptime-watcher] $1 $2"; }
+    silent() { echo "[uptime-watcher] silent: $1 $2"; }
+    wake() { echo "[uptime-watcher] WAKE $1 $2"; }
+fi
+
+# --- identity (per-machine, persistent) ---
+ENV_FILE="$HOME/workspace/tunnel/machine.env"
+# shellcheck disable=SC1090
+[ -f "$ENV_FILE" ] && . "$ENV_FILE"
+MACHINE="${MUSE_MACHINE:-unknown}"
+SSH_PORT="${SSH_PORT:-0}"
+TERM_PORT="${TERM_PORT:-0}"
+
+STATE_DIR="$HOME/hooks/state/uptime-watcher"
+BIN="$HOME/workspace/bin"
+RECOVER="$BIN/recover-after-rebuild.sh"
+SUPERVISOR="$BIN/gcp-tunnel-up.sh"
+CRON_RESTORE="$BIN/persistent-crontab.sh"
+SSH_KEY="$HOME/.ssh/vm_to_gcp"
+GCP_HOST="${FD_VM_HOST:-34.139.37.135}"
+GCP_USER="${FD_VM_USER:-super}"
+FAIL_COUNT="$STATE_DIR/consec_failures"
+LAST_WAKE="$STATE_DIR/last_wake_ts"
+
+mkdir -p "$STATE_DIR"
+exec 9>"$STATE_DIR/watcher.lock"
+flock -n 9 || { silent "previous poll still running" '{}'; exit 0; }
+read_int() { [ -f "$1" ] && tr -cd '0-9' < "$1" || echo 0; }
+
+actions=""
+fail=""
+
+# --- 1. fresh rebuild? provision ---
+if [ ! -f /etc/hatch-provisioned ]; then
+    if [ -x "$RECOVER" ]; then
+        if timeout 280 "$RECOVER" >"$STATE_DIR/recover-last.log" 2>&1; then
+            actions="${actions}provisioned "
+            log "recovery" '{"event":"provisioned_after_rebuild"}'
+        else
+            fail="recover_failed"
+        fi
+    else
+        fail="recover_missing"
+    fi
+fi
+
+# --- 2. supervisor alive? respawn ---
+if [ -z "$fail" ] && ! pgrep -f "workspace/bin/gcp-tunnel-up\.sh$" >/dev/null; then
+    if [ -x "$SUPERVISOR" ] && [ -f "$SSH_KEY" ]; then
+        setsid nohup "$SUPERVISOR" >/dev/null 2>&1 < /dev/null 9>&- &
+        disown 2>/dev/null || true
+        actions="${actions}supervisor-respawned "
+        log "supervisor" '{"event":"respawned"}'
+    else
+        fail="supervisor_unstartable"
+    fi
+fi
+
+# --- 3. cron jobs alive? restore from persistent spec ---
+if [ -z "$fail" ] && [ -x "$CRON_RESTORE" ]; then
+    if "$CRON_RESTORE" >"$STATE_DIR/cron-last.log" 2>&1; then
+        grep -q "reinstalled" "$STATE_DIR/cron-last.log" \
+            && actions="${actions}cron-restored "
+    else
+        fail="cron_restore_failed"
+    fi
+fi
+
+# --- 4. VM forward answers? (banner check, cheap) ---
+ssh_state="unknown"
+if [ -z "$fail" ] && [ "$SSH_PORT" != "0" ] && [ -f "$SSH_KEY" ] \
+   && pgrep -f "[s]sh.*${SSH_PORT}:localhost:22" >/dev/null; then
+    banner="$(timeout 12 ssh -i "$SSH_KEY" \
+        -o ProxyCommand="$BIN/ssh-via-proxy %h %p" \
+        -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null \
+        -o ConnectTimeout=8 -o BatchMode=yes \
+        "$GCP_USER@$GCP_HOST" \
+        "timeout 5 bash -c 'exec 3<>/dev/tcp/127.0.0.1/$SSH_PORT && head -c 4 <&3' 2>/dev/null" \
+        2>/dev/null || true)"
+    case "$banner" in
+        SSH-*) ssh_state="up" ;;
+        *) ssh_state="stale-forward"; fail="forward_dead" ;;
+    esac
+elif [ -z "$fail" ]; then
+    ssh_state="down"
+    fail="tunnel_down"
+fi
+
+payload="$(printf '{"machine":"%s","ssh":"%s","actions":"%s"}' \
+    "$MACHINE" "$ssh_state" "${actions:-none}")"
+
+# --- 5. silent ok, or rate-limited wake on persistent failure ---
+if [ -z "$fail" ]; then
+    printf 0 > "$FAIL_COUNT"
+    silent "uptime watcher poll ok" "$payload"
+    exit 0
+fi
+
+count=$(( $(read_int "$FAIL_COUNT") + 1 ))
+printf '%s' "$count" > "$FAIL_COUNT"
+log "failure" "{\"condition\":\"$fail\",\"consec\":\"$count\"}"
+if [ "$count" -ge 2 ]; then
+    now=$(date +%s); last=$(read_int "$LAST_WAKE")
+    if [ $(( now - last )) -ge 1800 ]; then
+        printf '%s' "$now" > "$LAST_WAKE"
+        wake "$fail" "$payload"
+        exit 0
+    fi
+fi
+silent "failure $fail ($count) — below wake threshold" "$payload"

docs/213-ssh-perms-verification.md

@@ -0,0 +1,38 @@
+# Ticket #213 verification — SSH key perms and container dial-in (646)
+
+Date: 2026-10-09 ~22:50 UTC
+Operator: operator-646 (muse-646-patha)
+Branch: `dev/646/213-fix-ssh-perms`
+
+## 1. authorized_keys permissions (port 2226 dial-in)
+
+- `~/.ssh/authorized_keys` (`/home/hatch/.ssh/authorized_keys`):
+  - before: `600 root:root`
+  - ran `chmod 600 ~/.ssh/authorized_keys` per ticket
+  - after: `600 root:root` (no-op — already correct)
+- sshd's requirement (private key file must not be group/world-writable,
+  ideally 600) is satisfied. `~/.ssh` itself is `700`.
+
+## 2. Container sshd
+
+- `sshd` running (pid 2655, listener, 0 of 10-100 startups).
+- Listening on `0.0.0.0:22` and `[::]:22`.
+- `authorized_keys` holds 1 key:
+  - `ssh-ed25519 SHA256:UOeqKF5BehWNmEpBSk53Qhz0Jd9aQXbFO0VKe2AVo8c`
+    (comment `super@bl`) — dial-in identity belongs to super.
+
+## 3. Reverse tunnel (VM 2226 → container:22)
+
+- On VM 34.139.37.135 (as dev-operator-646): `127.0.0.1:2226` and
+  `[::1]:2226` are LISTENING — the reverse tunnel is up.
+- Bind is loopback-only (no GatewayPorts), so dial-in must originate
+  from the VM itself — expected for `ssh -R` forwards.
+
+## 4. Dial-in path verdict
+
+Container-side prerequisites are all green: perms 600, sshd listening,
+tunnel established, authorized key present. The final key-auth step can
+only be completed by the holder of the `super@bl` private key, so no
+full loopback auth was attempted from this operator identity.
+
+Fixes #213

docs/215-strictmodes-verification.md

@@ -0,0 +1,57 @@
+# Ticket #215 verification — SSH StrictModes on /home/hatch
+
+Date: 2026-10-09 ~23:00 UTC
+Operator: operator-646 (muse-646-patha)
+Branch: `dev/646/215-strictmodes-fix`
+
+## Ticket premise
+
+#215 claims OpenSSH StrictModes rejects public-key auth on port 2226
+"for user hatch" because `/home/hatch` is `drwxrws---` (group-writable
+setgid), and asks whether `chmod g-w /home/hatch` or `StrictModes no`
+permits dial-in.
+
+## Investigation
+
+1. **No `hatch` user exists.** `/etc/passwd` has only `root` plus system
+   `nologin` users. The only viable dial-in identity is `root`
+   (`PermitRootLogin without-password`, i.e. pubkey-only).
+2. **Effective sshd config** (`sshd -T`): `strictmodes yes`,
+   `authorizedkeysfile .ssh/authorized_keys .ssh/authorized_keys2`
+   (relative to the login user's passwd home — for root, `/root`).
+3. **Root's auth path is StrictModes-clean** and does not include
+   `/home/hatch`:
+   - `/` → `755 root:root`
+   - `/root` → `700 root:root`
+   - `/root/.ssh` → `700 root:root`
+   - `/root/.ssh/authorized_keys` → `600 root:root` (holds 646's
+     `id_ed25519.pub` + `id_frontdoor.pub`, installed by
+     `recover-after-rebuild.sh` §2 — by design)
+4. **Empirical dial-in test (the decisive check).** From the VM over the
+   live reverse tunnel, with `/home/hatch` still `2770` (group-writable):
+   `ssh -p 2226 root@127.0.0.1` with agent-forwarded `id_frontdoor`
+   → `DIALIN_OK`, `whoami` → `root`. Public-key dial-in on 2226
+   **works with zero changes**.
+
+## Verdict
+
+Neither proposed remediation is required or was applied:
+
+- `chmod g-w /home/hatch` — unnecessary for SSH (path not consulted);
+  would also alter the setgid shared-directory semantics for no benefit.
+- `StrictModes no` in sshd config — unnecessary, and would weaken
+  authentication security globally.
+
+The StrictModes denial described in #215 cannot occur for the actual
+login path. No sshd reload was needed (no config changed).
+
+## Adjacent real gap (flagged, not fixed — needs a decision)
+
+`super@bl`'s ed25519 key (`SHA256:UOeqKF5B…`) lives only in
+`/home/hatch/.ssh/authorized_keys`, which sshd **never reads** (no
+`hatch` user exists). If super needs 2226 dial-in, that key must be
+appended to `/root/.ssh/authorized_keys`. The recover script
+deliberately installs only 646's own keys there, so this is a
+provisioning decision for 646/super — left untouched.
+
+Fixes #215

tests/test_uptime_watcher.py

@@ -0,0 +1,37 @@
+import os
+import subprocess
+import tempfile
+import unittest
+
+REPO_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+SCRIPT_PATH = os.path.join(REPO_DIR, "cloud-uptime", "uptime-watcher.sh")
+
+class TestUptimeWatcher(unittest.TestCase):
+    def test_script_exists_and_executable(self):
+        self.assertTrue(os.path.exists(SCRIPT_PATH), f"Script missing: {SCRIPT_PATH}")
+        self.assertTrue(os.access(SCRIPT_PATH, os.X_OK), "Script not executable")
+
+    def test_bash_syntax_check(self):
+        proc = subprocess.run(["bash", "-n", SCRIPT_PATH], capture_output=True, text=True)
+        self.assertEqual(proc.returncode, 0, f"Bash syntax error: {proc.stderr}")
+
+    def test_watcher_execution_in_sandbox(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            hooks_state = os.path.join(tmpdir, "hooks", "state", "uptime-watcher")
+            os.makedirs(hooks_state, exist_ok=True)
+            ws_tunnel = os.path.join(tmpdir, "workspace", "tunnel")
+            os.makedirs(ws_tunnel, exist_ok=True)
+            
+            env_file = os.path.join(ws_tunnel, "machine.env")
+            with open(env_file, "w") as f:
+                f.write("MUSE_MACHINE=test-node\nSSH_PORT=2224\nTERM_PORT=7681\n")
+                
+            env = os.environ.copy()
+            env["HOME"] = tmpdir
+            # Running with dry environment should safely exit (fail count tracked)
+            proc = subprocess.run([SCRIPT_PATH], env=env, capture_output=True, text=True)
+            # The script exits 0 even on fail unless fatal crash, logging status
+            self.assertTrue(os.path.exists(os.path.join(hooks_state, "consec_failures")))
+
+if __name__ == "__main__":
+    unittest.main()