D4 (R-982): root SSH from the LAN by key only — the bundle's sshd drop-in, try-reload-or-restart, an sshd -T read-back reported when not in force, a reload in undo (the reviewed v2 patch); unreleased

CHANGELOG.md

@@ -1,4 +1,64 @@
-## Unreleased (2026-10-21) — every guest may swap as much as its RAM (R-1192, the 8 GB freeze) — COMMITTED, NOT RELEASED (the release is the operator's word)
+## Unreleased (2026-10-22/23 night) — the tunnel heals itself after a clock that ran ahead (D30, R-1204) — COMMITTED, NOT RELEASED
+
+- **D30 (operator 2026-10-22: the agent makes a new key and registers it on the existing peer path).** When the latest
+  handshake stays stamped in the future for 15 minutes (the R-1204 sign: ep0 keeps the future timestamp and refuses
+  every newer handshake from that key), the agent makes a new WireGuard key pair, keeps the old private key as
+  `wg/private.key.prev` (0600 — the escrow may hold it), and registers the new public key through `POST /hosts/<id>/wg`.
+  The hub re-keys the peer IN PLACE (same /32, generation bump) and its full-list push to ep0 drops the old key and adds
+  the new one — nothing new runs on ep0. A new key is a new peer for ep0, with no stored timestamp, so the next
+  handshake is accepted. At most once an hour; not while the tunnel unit is down; never while a re-register is already
+  in flight. A failed registration is retried by the existing re-key-in-place path. Logs carry public keys only.
+  Tests `TestD30_*` (4), red-proved. A host-loss DR that installs the escrowed (older) key registers it again, and the
+  hub re-keys in place back to it — the same path.
+- **Review of the night's own code (felhom.eu `REPORT-night-2026-10-23.md`, N6, N7).** The rotation never leaves the box
+  without a readable key: the new key is written and fsynced to a temp file, the current key gets its kept name by a
+  hard link, then the temp file is renamed OVER `private.key` and the directory fsynced (a power cut or a kill between
+  two renames used to leave no key, or an empty one). `private.key.prev` keeps the FIRST old key (the escrow may hold it);
+  later ones are `private.key.prev.<unix>`, the newest three kept. The once-an-hour bound is saved in `wg/last-rekey`, so
+  an agent restart does not reset it; a start or a last re-key dated AFTER now (a clock that jumped back) is dropped,
+  never a block until that date (the commit's own security review). Tests `TestD30_TwoRotationsKeepTheFirstOldKey`,
+  `TestD30_ALastReKeyFromTheFutureDoesNotBlock`,
+  `TestD30_TheHourBoundSurvivesARestart`, red-proved. **Live (felhom.eu `audits/night-2026-10-23/P2-D30/`):** the D30
+  re-key ran on a test box (before these two changes): clock corrected → 15 min → new key registered → the box switched
+  at its next desired-state fetch → a handshake with the new key.
+- **D4 (operator ruling 2026-10-22, R-982) — root SSH from the LAN by key only, on `main` now (2026-10-23 day brief).** The
+  config bundle carries `/etc/ssh/sshd_config.d/10-felhom-root-key-only.conf` (`PermitRootLogin prohibit-password`;
+  content check: exactly that line, `sshd -t -f`). After an install that wrote it: `sshd -t` (the whole config), then
+  `systemctl try-reload-or-restart ssh` (a stopped or socket-activated sshd no longer refuses the bundle), then `sshd -T`
+  is read back and a drop-in that is NOT in force (no Include, an earlier drop-in, a Match block) is said loudly and
+  reported as `sshd_dropin_not_in_force` — never a refusal; an undone bundle reloads sshd again. The console and the
+  web page keep the root password; felhom-sshd (8822) is not touched. Tests `RootKeyOnly` (6), red-proved; the
+  installer's uninstall removes the file (felhom.eu installer 1.36.0). Reviewed 2026-10-23 night (A1–A7).
+- **Known gap, unchanged (filed):** after a reboot the kernel forgets the future stamp (latest handshake 0), so neither
+  this re-key nor the hub's alarm sees a box whose clock was corrected and which then restarted (R-1223).
+
+## Unreleased (2026-10-22 night) — the tunnel's future-stamped handshake is reported (R-1204) — COMMITTED, NOT RELEASED (no agent release tonight); root SSH by key only (R-982, D4) is a READY PATCH, not on main
+
+- **R-982 / D4 — a ready patch, NOT on main.** Built and proven the same night (felhom.eu
+  `audits/night-2026-10-22/P2-D4/`): a bundle drop-in `/etc/ssh/sshd_config.d/10-felhom-root-key-only.conf`
+  (`PermitRootLogin prohibit-password`), a `sshd` content check (exactly `prohibit-password`; `sshd -t -f`), and after
+  an install that wrote it `sshd -t` + `systemctl reload ssh`; tests `RootKeyOnly` (3), red-proved. Live on a fresh
+  nested box from ISO 1.30.0: root password over SSH refused, root key works, the console and the web page still take
+  the password. It was committed (`a0c88e5`) and moved back out (`7651461`): the installer's uninstall must remove every bundle file (felhom.eu `scripts/test_hostinstall.py`), the bundle half reaches a box only with an agent release, and the installer half only with a new `installer-v…` tag (R-110 — a push to `main` alone publishes nothing) — both forbidden tonight. *(Corrected the same night: the first reason written here, „a push of `felhom-host-install.sh` publishes the installer", was wrong — the website serves `/scripts/` from the tag `installer-v1.35.0`, read live in `manifests/webpage.yaml` and the running Deployment.)* Both halves are patches: `felhom-agent-bundle-D4.patch` and `felhom.eu-installer-D4.patch` in that folder; apply them together with the agent release and the next installer tag.
+- **R-1204 — `wireguard.handshake_future_s`.** A box that ran once with its clock ahead keeps a handshake stamped in the
+  future; ep0 refuses every newer one, and `last_handshake_age_s` (clamped at 0) read „just now" for ever. The heartbeat
+  now carries how many seconds the handshake lies ahead (> 60 s only); the age keeps its clamp. The hub alarms on it
+  (felhom.eu hub `wg_tunnel_stale`). Test `TestR1204_AFutureHandshakeIsReported`, red-proved.
+
+## v0.162.0 — every guest may swap as much as its RAM (R-1192, the 8 GB freeze); the host's swap is reported and checked; no false „operator access degraded" on a fresh box (R-1194) (2026-10-22) — RELEASED on the operator's yes; the vouch is the operator's
+
+Released 2026-10-22 07:40 UTC (operator yes, the morning answers) with `scripts/release-agent.sh` from a clean clone at
+`b310773`: binary sha256 `5fd7a23bfe319cb521c4bc399612d5fb3413f1e695f79bc663c386f69c757928` (the same bytes as the
+night's candidate), config bundle sha256 `ac772967fd4669045e837a70bf5acca239c58d55f7f00212e472a8facd60b5a5`, tag
+`v0.162.0`; no `configs/` change since v0.161.0. Delivered by one signed `agent_update` job per box to demo-hp, Tester 1
+and demo-felhom (07:49–07:58 UTC): each `signed op COMPLETED`, `capabilities self-check ok=76 total=76`, `update
+committed`, then `guest-swap: raised` for its 9201 (512 MB → its RAM). Evidence felhom.eu
+`documentation/audits/morning-2026-10-22/release/04-agent-delivery.txt`. **Found at once:** demo-hp (host swap 8191 MB,
+guest swap 25898 MB) and demo-felhom (8191 MB vs 12288 MB) logged the host-swap WARN and the hub mailed
+`host_swap_short` — the check compares the host's swap with the guests' whole swap allowance, which a guest larger
+than the installer's 8 GB host swap always exceeds (felhom.eu register R-1216). Soak (night of 2026-10-21, 8 GB box):
+11 h, no freeze, the host's swap peaked at 2.7 GB used.
+
 
 The freeze of the rehearsal's first afternoon, reproduced and measured on demo-hp (felhom.eu
 `audits/fixes-2026-10-21/P4-freeze/`): Proxmox gives an LXC a 512 MB swap cap when nothing sets `swap`, and the agent

CONTEXT.md

@@ -1,5 +1,13 @@
 # CONTEXT — felhom-agent working state
 
+> **2026-10-22/23 night — D30 on `main` (`ae69ad4`), unreleased; the D4 patches v2 ready.** Operator ruling D30
+> (2026-10-22): a handshake stamped in the future for 15 min → a new WG key pair (`wgtunnel/rekey.go`; old key kept as
+> `wg/private.key.prev`), registered on `POST /hosts/<id>/wg` (the hub re-keys in place; its full-list push swaps the
+> key on ep0). Live on a test box (felhom.eu `audits/night-2026-10-23/P2-D30/`): with ep0 free to start a handshake the
+> tunnel heals by itself (no re-key, correct); with ep0's starts dropped it stays dead and the agent re-keyed at 15 min.
+> The interface switches at the next desired-state fetch. Gap: a reboot forgets the future stamp (R-1223). The D4 bundle
+> patch v2 (`P3-review/felhom-agent-bundle-D4-v2.patch`): `try-reload-or-restart`, an `sshd -T` read-back reported as
+> `sshd_dropin_not_in_force`, a reload in undo. Next agent release = D30 + D4 v2 + R-1204's field, the operator vouches.
 > **2026-10-20 — v0.161.0 RELEASED (operator yes), NOT VOUCHED; on demo-hp, Tester 1, demo-felhom** (signed jobs, all
 > committed, 76/76). R-921 `host_busy` (proven live on demo-hp during a press), R-1070 the tunnel `absent` state (9202's
 > real Docker 29 answer is the fixture row), R-1010 the janitor's one `force=1`. Vouch: version 0.161.0, sha256

REPORT.md

@@ -1,18 +1,23 @@
-# REPORT — agent, the night of 2026-10-21: the host's swap is reported; no false emergency-door alarm on a new box — COMMITTED, NOT RELEASED
+# REPORT — night 2026-10-22 → 23: D30 on `main`, the D4 patches v2, nothing released
 
-**Brief:** the unattended night brief of 2026-10-21 (Parts 1, 2, 5). Architecture: felhom.eu `03-host-agent.md` §9 (the
-new swap paragraph). Both join the swap fix (`286a7e3`) in the coming 0.162.0 — the operator's release and vouch (D26 = A).
+**What:** the night brief's agent parts. No release, no vouch. Design read: `03-host-agent.md` (the tunnel, the key, the
+bundle), `06-offsite-connectivity.md` (the full-list push to ep0).
 
-- **Host swap (R-1192 follow-up), `0da792e`:** the host report carries `host.host_swap_mb` (Proxmox node status = the
-  kernel's SwapTotal) and `host.guest_swap_mb` (the guests' `swap` sum; each guest spec `swap_bytes`); one WARN when the
-  first is below the second, one INFO when covered again; `GET /guest/memory` carries both for the controller's install
-  page. The agent never creates host swap (register R-1207). Proven live on the soak box: the hub stored
-  `host_swap_mb 7935, guest_swap_mb 4096`.
-- **R-1194, `0da792e`:** no OOB stanza until the felhom-sshd loop's first pass has run — the first report on a fresh box
-  read a config not yet rendered and the hub mailed `oob_degraded` (reproduced 2026-10-21 20:34 CEST on a fresh install).
-- **The swap fix itself** ran as a hand-placed fixture on the 8 GB soak box: guest swap 512 → 4096 MB one minute after
-  start; the 2-hour household load answered every probe (felhom.eu `audits/night-2026-10-21/P1-soak/`).
-- Release candidate built from a clean clone at `0da792e` with the release flags, version `0.162.0`:
-  sha256 `5fd7a23bfe319cb521c4bc399612d5fb3413f1e695f79bc663c386f69c757928` (not published).
-- Tests (red-proved): `TestR1192_HostReportCarriesSwapAndWarnsOnce`, `TestR1192_GuestMemoryCarriesHostAndGuestSwap`,
-  `TestR1194_NoOOBStanzaBeforeTheFirstPass`. CI job 2176 green.
+- **D30** (`ae69ad4`, hardened `39fb9cb`, `b9b831f`): a handshake stamped in the future for 15 min → a new key pair,
+  registered on `POST /hosts/<id>/wg` (the hub re-keys in place; its full-list push swaps the key on ep0 — nothing new
+  on ep0). The key file is replaced by an fsynced rename over it (never missing or empty); the first old key stays
+  `private.key.prev`, later ones dated (3 kept); the once-an-hour bound survives a restart; a wait stamp dated after now
+  is dropped. Tests `TestD30_*` (7), each red-proved.
+- **Live** (felhom.eu `audits/night-2026-10-23/P2-D30/`, test box Tester4-16fdef, fixture `ae69ad4`): with ep0 free to
+  start a handshake, a 2-hour clock jump healed by itself and no re-key ran (correct); with ep0's starts dropped on the
+  box, the tunnel stayed dead, the agent re-keyed at 15 min, the hub took the key (`existed=false generation=3
+  sync=ok`), the box switched at its next desired-state fetch and shook hands with the new key.
+- **D4 patches v2** (felhom.eu `audits/night-2026-10-23/P3-review/`), after a fresh review (A1–A7): `try-reload-or-restart`,
+  an `sshd -T` read-back reported as `sshd_dropin_not_in_force`, a reload in undo, the right citation; installer: a warning
+  when the reload fails. RootKeyOnly 6/6 (two new, red-proved); installer tests 40/40 with the patch. Both apply to
+  tonight's mains. Live by hand on the test box: root password SSH refused, key works, web password 200.
+- **Gap filed:** a reboot after the clock was corrected forgets the future stamp (felhom.eu R-1223).
+
+CI by commit: `ae69ad4` 2229, `39fb9cb` 2235 green; `b9b831f` and this docs commit: see felhom.eu
+`REPORT-night-2026-10-23.md`. Fixture names on the test box: `0.163.0-night.1` (= `ae69ad4`), then `0.162.99`
+(= `b9b831f`; a plain number, because the controller cannot compare a pre-release string — the off-site unlock refused).

configs/felhom-os-apply

@@ -165,7 +165,8 @@ KERNEL_ACTIVE = ("staged", "oneshot", "judging", "reverting")
 #   dest: (source file under configs/, mode, check, policy)
 # check:  the content check BEFORE anything is written (R18): sudoers → visudo -cf; sh / bash → -n; python → compile;
 #         unit → a [Unit]/[Service]/[Timer] section; unit-nort → that, and never RuntimeDirectory= (the G1 incident);
-#         agent-unit → User=felhom-agent; dropin → a [Unit] section (SF-3); nft → nft -c -f; plain → none.
+#         agent-unit → User=felhom-agent; dropin → a [Unit] section (SF-3); nft → nft -c -f; plain → none;
+#         sshd → `sshd -t -f` on the snippet alone (R-982).
 # policy: replace → always written when it differs; if-absent → only when the box has none (a setting the operator may
 #         have tuned); oob → only on a box with the OOB belt (/etc/felhom-sshd exists — the installer's --no-oob leaves none).
 # Order matters: the sudoers files come LAST, so a referenced wrapper is in place before the line that allows it.
@@ -184,6 +185,9 @@ BUNDLE_KEEP = 3
 BUNDLE_MAX_BYTES = 4 * 1024 * 1024
 BUNDLE_RE = re.compile(r"^bundle-[0-9]+\.[0-9]+\.[0-9]+(-[0-9A-Za-z.]+)?\.json$")
 OOB_DIR = "/etc/felhom-sshd"
+# R-982: the host's own sshd drop-in (after_install reloads sshd for it; undo reloads after putting it back).
+SSHD_DROPIN = "/etc/ssh/sshd_config.d/10-felhom-root-key-only.conf"
+
 BUNDLE_FILES = [
     ("/usr/local/sbin/felhom-mkfs-guarded", "felhom-mkfs-guarded.sh", 0o755, "bash", "replace"),
     ("/usr/local/sbin/felhom-selfupdate-guarded", "felhom-selfupdate-guarded", 0o755, "sh", "replace"),
@@ -221,6 +225,9 @@ BUNDLE_FILES = [
     ("/etc/systemd/system/felhom-sshd.service", "felhom-sshd.service", 0o644, "unit-nort", "oob"),
     ("/etc/felhom-oob.nft", "felhom-oob.nft", 0o644, "nft", "oob"),
     ("/etc/systemd/system/felhom-oob-nft.service", "felhom-oob-nft.service", 0o644, "unit", "oob"),
+    # R-982, operator ruling D4 (2026-10-22): the host's own sshd (port 22, the LAN): root by key only. The console
+    # password stays; felhom-sshd (the operator's door) reads nothing from sshd_config.d. Reloaded in after_install.
+    ("/etc/ssh/sshd_config.d/10-felhom-root-key-only.conf", "felhom-root-ssh-key-only.conf", 0o644, "sshd", "replace"),
     ("/etc/sudoers.d/felhom-op", "felhom-op.sudoers", 0o440, "sudoers", "oob"),
     ("/etc/sudoers.d/felhom-agent", "felhom-agent.sudoers", 0o440, "sudoers", "replace"),
 ]
@@ -434,7 +441,8 @@ class Runner:
     def check_content(self, kind, data):
         """Run an external syntax check on a root-only temp copy. Returns (rc, message)."""
         import tempfile
-        cmd = {"sudoers": ["visudo", "-cf"], "sh": ["sh", "-n"], "bash": ["bash", "-n"], "nft": ["nft", "-c", "-f"]}[kind]
+        cmd = {"sudoers": ["visudo", "-cf"], "sh": ["sh", "-n"], "bash": ["bash", "-n"], "nft": ["nft", "-c", "-f"],
+               "sshd": ["/usr/sbin/sshd", "-t", "-f"]}[kind]
         with tempfile.TemporaryDirectory(prefix="felhom-bundle-") as d:
             p = os.path.join(d, "f")
             with open(p, "wb") as f:
@@ -1864,6 +1872,7 @@ class Bundle:
     def __init__(self, apply):
         self.a, self.r = apply, apply.r
         self.report = apply.report
+        self.sshd_dropin_not_in_force = False
 
     # ---------- reading and checking ----------
     def load_file(self, path):
@@ -1932,10 +1941,17 @@ class Bundle:
             text = content.decode("utf-8")
         except UnicodeDecodeError:
             raise Refused("R18", f"{dest} is not UTF-8 text")
-        if check in ("sudoers", "sh", "bash", "nft"):
+        if check in ("sudoers", "sh", "bash", "nft", "sshd"):
             rc, msg = self.r.check_content(check, content)
             if rc != 0:
                 raise Refused("R18", f"{dest} fails its {check} check: {msg}")
+        if check == "sshd":
+            # R-982: the drop-in's PermitRootLogin must be exactly `prohibit-password`. `no` would also shut the root key
+            # out (Proxmox's own node-to-node SSH and the LAN key route), `yes` would undo the ruling — both refused.
+            # Only that line is pinned: the file is signed like every bundle file (review A7).
+            vals = re.findall(r"^\s*PermitRootLogin\s+(\S+)\s*$", text, re.M | re.I)
+            if vals != ["prohibit-password"]:
+                raise Refused("R18", f"{dest} must set exactly `PermitRootLogin prohibit-password` (found {vals})")
         elif check == "python":
             try:
                 compile(text, dest, "exec")
@@ -2044,6 +2060,8 @@ class Bundle:
             self.report["failed"] = {"rc": 3, "step": "bundle", "reason": reason[:300]}
             return 3
         rep["signers_created"] = False
+        if self.sshd_dropin_not_in_force:
+            rep["sshd_dropin_not_in_force"] = True  # R-982 A2: written and reloaded, but sshd -T shows root passwords allowed
         if bootstrap and not self.r.lexists(TRUST_SIGNERS):
             self.r.put_file(TRUST_SIGNERS, pinned_signers_line().encode(), 0o644)
             rep["signers_created"] = True
@@ -2073,6 +2091,23 @@ class Bundle:
                       "enable the crash guard")
         if "/etc/systemd/system/felhom-mgmt-watchdog.timer" in dests:
             self.must(["systemctl", "enable", "--now", "felhom-mgmt-watchdog.timer"], "enable the mgmt watchdog timer")
+        # R-982: the host's sshd takes the root-key-only drop-in. The WHOLE config is tested first (a failure is a
+        # refusal, and the bundle undo puts the old files back); `try-reload-or-restart` keeps every open session and
+        # does nothing on a box whose ssh.service is not running (a socket-activated or stopped sshd reads the file
+        # at its next start) — a failure there must not freeze the bundle route (review 2026-10-22 night, A1).
+        # felhom-sshd is not touched. Then the POSITIVE check: sshd's own effective view for root. A box whose
+        # sshd_config has no Include of sshd_config.d, an earlier drop-in or a Match block can keep the password route
+        # — that is said loudly in the log and the report, never silently recorded as done (A2).
+        if SSHD_DROPIN in written:
+            self.must(["/usr/sbin/sshd", "-t"], "sshd -t (the host's whole sshd config)")
+            self.must(["systemctl", "try-reload-or-restart", "ssh"], "systemctl try-reload-or-restart ssh")
+            rc, out, err = self.r.host(["/usr/sbin/sshd", "-T", "-C", "user=root,host=felhom-check,addr=192.0.2.1"], 60)
+            eff = re.findall(r"^permitrootlogin\s+(\S+)", out, re.M | re.I)
+            if rc != 0 or eff != ["without-password"]:
+                self.r.log(f"os-apply: BUNDLE WARNING the root-key-only drop-in is NOT in force: sshd -T says "
+                           f"permitrootlogin={eff or '?'} (rc={rc}) — check sshd_config's Include, an earlier drop-in "
+                           f"or a Match block (R-982)")
+                self.sshd_dropin_not_in_force = True
 
     def must(self, argv, what):
         rc, out, err = self.r.host(argv, 120)
@@ -2133,6 +2168,9 @@ class Bundle:
                 self.r.log(f"os-apply: BUNDLE UNDO could not restore {dest}: {e}")
         if any(d.startswith("/etc/systemd/system/") for d in back):
             self.r.host(["systemctl", "daemon-reload"], 120)
+        if SSHD_DROPIN in back:
+            # A3: after_install may already have reloaded sshd with the drop-in; the restored state takes effect now.
+            self.r.host(["systemctl", "try-reload-or-restart", "ssh"], 120)
         rc, _, _ = self.r.host(["visudo", "-c"], 60)
         self.r.log(f"os-apply: BUNDLE UNDO restored={len(back)} visudo-after={'ok' if rc == 0 else 'FAILED'}")
         return back

configs/felhom-root-ssh-key-only.conf

@@ -0,0 +1,7 @@
+# MANAGED BY FELHOM (the agent's config bundle) — R-982, operator ruling D4 (2026-10-22).
+# The Proxmox host's OWN sshd — the listener the household network reaches on port 22: root logs in with a KEY only.
+# The root password still works on the console (the break-glass password: felhom.eu runbooks/break-glass.md). The
+# operator's door (felhom-sshd, port 8822, /etc/felhom-sshd/sshd_config) is a separate daemon whose config includes
+# nothing from here, so it is not changed. Debian's sshd_config reads this folder BEFORE its own settings, and for
+# sshd the first value wins; the bundle checks the effective value with `sshd -T` after the reload.
+PermitRootLogin prohibit-password

configs/test_felhom_config_bundle.py

@@ -429,6 +429,90 @@ class SelfCheckUndo(unittest.TestCase):
         self.assert_restored(box, before, rep)
 
 
+
+class RootKeyOnly(unittest.TestCase):
+    """R-982, operator ruling D4 (2026-10-22): the bundle gives the host's own sshd a root-key-only drop-in, tests the
+    whole config and reloads sshd — only when the file was written; a drop-in that says anything but
+    `prohibit-password` is refused before anything is written.
+    RED-PROOF: with the after_install block removed, test_fresh_box_takes_the_dropin_and_reloads fails (no reload);
+    with the content rule removed, test_a_dropin_that_says_yes_or_no_is_refused fails — seen failing 2026-10-22."""
+    DEST = "/etc/ssh/sshd_config.d/10-felhom-root-key-only.conf"
+
+    def test_fresh_box_takes_the_dropin_and_reloads(self):
+        data, sha = real_bundle()
+        box = Box(data, signed_job(sha))
+        rc, rep = run(box)
+        self.assertEqual(rc, 0, rep)
+        self.assertIn(b"PermitRootLogin prohibit-password", box.files[self.DEST])
+        self.assertEqual(box.modes[self.DEST], 0o644)
+        self.assertIn(["/usr/sbin/sshd", "-t"], box.calls)
+        self.assertIn(["systemctl", "try-reload-or-restart", "ssh"], box.calls)
+        self.assertLess(box.calls.index(["/usr/sbin/sshd", "-t"]), box.calls.index(["systemctl", "try-reload-or-restart", "ssh"]))
+        self.assertFalse(any("felhom-sshd" in " ".join(c) for c in box.calls), "the operator's door must not be touched")
+
+    def test_an_unchanged_dropin_is_not_reloaded(self):
+        data, sha = real_bundle()
+        box = Box(data, signed_job(sha))
+        box.put(self.DEST, (REPO / "configs" / "felhom-root-ssh-key-only.conf").read_bytes(), 0o644)
+        rc, rep = run(box)
+        self.assertEqual(rc, 0, rep)
+        self.assertNotIn(["systemctl", "try-reload-or-restart", "ssh"], box.calls)
+
+    def test_a_dropin_that_says_yes_or_no_is_refused(self):
+        for bad in (b"PermitRootLogin yes\n", b"PermitRootLogin no\n", b"# nothing\n",
+                    b"PermitRootLogin prohibit-password\nPermitRootLogin yes\n"):
+            def edit(files, bad=bad):
+                for e in files:
+                    if e["path"] == self.DEST:
+                        e["content_b64"] = base64.b64encode(bad).decode()
+            data, sha = edited_bundle(edit)
+            box = Box(data, signed_job(sha))
+            rc, rep = run(box)
+            self.assertNotEqual(rc, 0, bad)
+            self.assertNotIn(self.DEST, box.files, bad)
+
+    # Review 2026-10-22 night. A2: the effective value is read back with `sshd -T`; a drop-in that is not in force is
+    # said in the log and the report (not refused — a refusal would freeze the bundle route). A3: a bundle undone
+    # after the reload reloads sshd again with the old state. RED-PROOF: with the sshd -T check removed,
+    # test_a_dropin_not_in_force_is_reported fails; with the undo reload removed, test_an_undone_bundle_reloads_sshd
+    # fails — seen failing 2026-10-22 night.
+    def _sshd_T(self, box, value):
+        orig = box.host
+        def host(argv, timeout=600, stdin=None):
+            if argv[:2] == ["/usr/sbin/sshd", "-T"]:
+                box.calls.append(argv)
+                return 0, f"port 22\npermitrootlogin {value}\npasswordauthentication yes\n", ""
+            return orig(argv, timeout, stdin)
+        box.host = host
+
+    def test_the_effective_value_is_checked(self):
+        data, sha = real_bundle()
+        box = Box(data, signed_job(sha))
+        self._sshd_T(box, "without-password")
+        rc, rep = run(box)
+        self.assertEqual(rc, 0, rep)
+        self.assertTrue(any(c[:2] == ["/usr/sbin/sshd", "-T"] for c in box.calls))
+        self.assertNotIn("sshd_dropin_not_in_force", rep["bundle"])
+
+    def test_a_dropin_not_in_force_is_reported(self):
+        data, sha = real_bundle()
+        box = Box(data, signed_job(sha))
+        self._sshd_T(box, "yes")   # e.g. no Include of sshd_config.d
+        rc, rep = run(box)
+        self.assertEqual(rc, 0, rep)
+        self.assertTrue(rep["bundle"].get("sshd_dropin_not_in_force"), rep)
+        self.assertTrue(any("NOT in force" in l for l in box.logs), box.logs)
+
+    def test_an_undone_bundle_reloads_sshd(self):
+        data, sha = real_bundle()
+        box = Box(data, signed_job(sha))
+        box.visudo_fail = True     # the self-check fails AFTER the install → undo
+        rc, rep = run(box)
+        self.assertEqual(rc, 3, rep)
+        self.assertNotIn(self.DEST, box.files)
+        reloads = [i for i, c in enumerate(box.calls) if c == ["systemctl", "try-reload-or-restart", "ssh"]]
+        self.assertEqual(len(reloads), 2, box.calls)   # after_install, then the undo
+
 class TrustBootstrap(unittest.TestCase):
     def test_missing_signers_verifies_against_the_pinned_key_and_creates_it(self):
         data, sha = real_bundle()

internal/hub/report.go

@@ -292,7 +292,11 @@ type WireguardStatus struct {
 	Registered        bool   `json:"registered"` // the registration marker exists
 	Active            bool   `json:"active"`     // wg-quick@wg-felhom is-active
 	LastHandshakeAgeS *int64 `json:"last_handshake_age_s,omitempty"`
-	AssignedIP        string `json:"assigned_ip,omitempty"` // from the marker, e.g. "10.77.0.2/32"
+	// HandshakeFutureS (R-1204): seconds the latest handshake lies in the FUTURE by this box's clock — set (> 0) only
+	// then. A box that ran once with its clock ahead keeps a handshake stamped in the future; WireGuard on ep0 then
+	// refuses every newer handshake, and LastHandshakeAgeS (clamped at 0) reads „just now" for ever. The hub alarms on it.
+	HandshakeFutureS *int64 `json:"handshake_future_s,omitempty"`
+	AssignedIP       string `json:"assigned_ip,omitempty"` // from the marker, e.g. "10.77.0.2/32"
 }
 
 // SystemInfo is the `system` stanza (see HostReport.System).

internal/wgtunnel/manager.go

@@ -99,6 +99,7 @@ type Manager struct {
 	resolver  Resolver
 
 	staleAfter time.Duration // handshake-age threshold for the re-resolve watchdog (doc 06 §4.2)
+	rekeyAfter time.Duration // D30: how long a future-stamped handshake stays before the re-key (rekey.go)
 
 	mu              sync.Mutex
 	nextRegAt       time.Time
@@ -111,6 +112,10 @@ type Manager struct {
 	resolveFailLogged bool       // DNS-failure log throttle (reset on the next success)
 	staleSameIPLogged bool       // "stale but IP unchanged" log throttle (endpoint-down, not re-IP)
 
+	// D30 (rekey.go): when the latest handshake was first seen stamped in the future, and the last re-key.
+	futureSince time.Time
+	lastRekey   time.Time
+
 	// conv is the CACHED tunnel-convergence snapshot (v0.90.0, R-28 fast-tick source), refreshed at
 	// the end of every Apply (the tunnel's own cadence) so the fast-tick reads it WITHOUT execing
 	// `wg`/`systemctl` per tick. wgBlockDesired = a wireguard block for THIS key is desired;
@@ -156,6 +161,7 @@ func NewManager(runner proxmox.Runner, registrar Registrar, stateDir string, log
 		now:        time.Now,
 		resolver:   netResolver{},
 		staleAfter: 180 * time.Second,
+		rekeyAfter: rekeyAfterDefault,
 	}
 }
 
@@ -600,6 +606,10 @@ func (m *Manager) Watchdog(ctx context.Context, fetched bool, block *hub.WireWir
 	if !fetched || block == nil || !m.lastResolvedIP.IsValid() {
 		return // nothing applied to watch, or no desired block
 	}
+	// D30: a handshake stamped in the future that stays → a new key on the existing peer path (rekey.go).
+	if m.clockAheadRekeyLocked(ctx, block) {
+		return
+	}
 	if !m.handshakeStaleLocked(ctx) {
 		return // healthy → no DNS, no action (the load-bearing negative)
 	}
@@ -661,6 +671,9 @@ func (m *Manager) Status(ctx context.Context) *hub.WireguardStatus {
 			if age, ok := parseHandshakeAge(string(out), m.now()); ok {
 				st.LastHandshakeAgeS = &age
 			}
+			if fut, ok := handshakeFuture(string(out), m.now()); ok {
+				st.HandshakeFutureS = &fut
+			}
 		}
 	}
 	if st.Pubkey == "" && !st.Registered && !st.Active {
@@ -669,6 +682,28 @@ func (m *Manager) Status(ctx context.Context) *hub.WireguardStatus {
 	return st
 }
 
+// handshakeFuture (R-1204) reports how many seconds the latest handshake lies in the future, ok only when it does
+// (by more than a minute — clock jitter is not the case). parseHandshakeAge clamps that case to 0 („just now"), which
+// is what made a box whose clock had run ahead look healthy while ep0 refused its tunnel. Pinned by
+// TestR1204_AFutureHandshakeIsReported.
+func handshakeFuture(out string, now time.Time) (int64, bool) {
+	for _, line := range strings.Split(strings.TrimSpace(out), "\n") {
+		f := strings.Fields(line)
+		if len(f) != 2 {
+			continue
+		}
+		epoch, err := strconv.ParseInt(f[1], 10, 64)
+		if err != nil || epoch <= 0 {
+			continue
+		}
+		if fut := epoch - now.Unix(); fut > 60 {
+			return fut, true
+		}
+		return 0, false
+	}
+	return 0, false
+}
+
 // parseHandshakeAge parses `wg show <if> latest-handshakes` output ("<peer-pub>\t<epoch>").
 // epoch 0 = no handshake yet → not ok (nil in the report; nil ≠ 0).
 func parseHandshakeAge(out string, now time.Time) (int64, bool) {

internal/wgtunnel/manager_test.go

@@ -696,3 +696,31 @@ func TestInitialResolveFailureNoTeardown(t *testing.T) {
 		t.Errorf("did not recover after DNS returned: %v", rr.calls)
 	}
 }
+
+// R-1204: a box that ran once with its clock ahead keeps a handshake stamped in the FUTURE — ep0 then refuses every
+// newer one. The age stays clamped at 0 (unchanged contract), and the new field says how far ahead it lies; a
+// handshake in the past (or within a minute of now) never sets it.
+// RED-PROOF: with Status not setting HandshakeFutureS the first assertion fails — seen failing 2026-10-22.
+func TestR1204_AFutureHandshakeIsReported(t *testing.T) {
+	fh := &fakeHub{}
+	m, _, active, _ := testManager(t, fh)
+	ctx := context.Background()
+	m.Apply(ctx, false, nil)
+	*active = true
+	m.now = func() time.Time { return time.Unix(1783107115-2*24*3600, 0) } // the clock came back two days earlier
+	st := m.Status(ctx)
+	if st.HandshakeFutureS == nil || *st.HandshakeFutureS != 2*24*3600 {
+		t.Fatalf("handshake_future_s = %v, want %d", st.HandshakeFutureS, 2*24*3600)
+	}
+	if st.LastHandshakeAgeS == nil || *st.LastHandshakeAgeS != 0 {
+		t.Fatalf("the age stays clamped at 0: %v", st.LastHandshakeAgeS)
+	}
+	m.now = func() time.Time { return time.Unix(1783107115+100, 0) }
+	if st = m.Status(ctx); st.HandshakeFutureS != nil {
+		t.Fatalf("a past handshake must not set handshake_future_s: %v", *st.HandshakeFutureS)
+	}
+	m.now = func() time.Time { return time.Unix(1783107115-30, 0) } // 30 s of jitter is not the case
+	if st = m.Status(ctx); st.HandshakeFutureS != nil {
+		t.Fatalf("clock jitter must not set handshake_future_s")
+	}
+}

internal/wgtunnel/rekey.go

@@ -0,0 +1,189 @@
+package wgtunnel
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+
+	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
+)
+
+// D30 (operator 2026-10-22, R-1204): the tunnel heals itself after the box ran with its clock ahead.
+//
+// WireGuard refuses a handshake whose timestamp is not newer than the last one it accepted from that key (replay
+// protection). A box whose clock ran ahead handshook with a future timestamp; ep0 keeps it, and once the clock is
+// right again ep0 refuses every new handshake from that key — until the box's clock passes the stored stamp. The
+// sign on the box: its own latest handshake stays stamped in the future (R-1204's handshake_future_s).
+//
+// The repair: when that sign stays for rekeyAfter, the agent makes a NEW key pair and registers the new public key on
+// the existing path (POST /hosts/<id>/wg → the hub re-keys the peer IN PLACE: same /32, new key, generation bump,
+// and the wgsync push of the FULL peer list to ep0 drops the old key and adds the new one). A new key is a new peer
+// for ep0, with no stored timestamp — the next handshake is accepted. Nothing new runs on ep0.
+//
+// The previous private key is kept as private.key.prev (0600): the escrow ceremony may hold it (a host-loss DR that
+// installs it registers it again, and the hub re-keys in place back to it — the same path).
+// Pinned by TestD30_* (rekey_test.go).
+
+const (
+	// rekeyAfter: how long the latest handshake must stay in the future before the re-key. A working tunnel
+	// handshakes every two minutes, which ends the sign within minutes of the clock being right.
+	rekeyAfterDefault = 15 * time.Minute
+	// rekeyMinGap bounds the re-key to once an hour, whatever the clock does.
+	rekeyMinGap = time.Hour
+	prevKeyName = "private.key.prev"
+)
+
+// clockAheadRekeyLocked watches for a handshake stamped in the future and re-keys when it stays. It reports whether
+// it re-keyed (the caller then skips the rest of its tick). Caller holds m.mu.
+func (m *Manager) clockAheadRekeyLocked(ctx context.Context, block *hub.WireWireguard) bool {
+	if m.keyBroken || !m.isActive(ctx) {
+		m.futureSince = time.Time{}
+		return false
+	}
+	out, _, err := m.runner.Run(ctx, "wg", "show", Iface, "latest-handshakes")
+	if err != nil {
+		return false
+	}
+	now := m.now()
+	fut, ok := handshakeFuture(string(out), now)
+	if !ok {
+		if !m.futureSince.IsZero() {
+			m.logger.Info("wgtunnel: the handshake is no longer stamped in the future — no re-key needed")
+		}
+		m.futureSince = time.Time{}
+		return false
+	}
+	if m.futureSince.IsZero() {
+		m.futureSince = now
+		m.logger.Warn("wgtunnel: the latest handshake is stamped in the future — this box's clock ran ahead, and the endpoint refuses its newer handshakes; re-keying if it stays",
+			"future_s", fut, "rekey_after", m.rekeyAfter.String())
+		return false
+	}
+	// A clock that jumps backwards must not stretch either wait (commit security review 2026-10-23 night): a start or a
+	// last re-key stamped AFTER now is from a wrong clock and is dropped — this whole feature exists because clocks jump.
+	if now.Before(m.futureSince) {
+		m.futureSince = now
+	}
+	if now.Sub(m.futureSince) < m.rekeyAfter {
+		return false
+	}
+	if m.lastRekey.IsZero() {
+		m.lastRekey = m.loadLastRekey()
+	}
+	if now.Before(m.lastRekey) {
+		m.lastRekey = time.Time{}
+	}
+	if !m.lastRekey.IsZero() && now.Sub(m.lastRekey) < rekeyMinGap {
+		return false
+	}
+	pub, _, err := EnsureKey(m.stateDir)
+	if err != nil || block.Pubkey != pub {
+		return false // a re-register is already in flight, or the key is not readable — never re-key over that
+	}
+	newPub, err := rotateKey(m.stateDir)
+	if err != nil {
+		m.logger.Error("wgtunnel: re-key after a future handshake FAILED — the old key stays", "err", err)
+		m.lastRekey = now // not again before rekeyMinGap
+		m.saveLastRekey(now)
+		return false
+	}
+	m.lastRekey, m.futureSince = now, time.Time{}
+	m.saveLastRekey(now)
+	m.logger.Warn("wgtunnel: RE-KEYED after a handshake stamped in the future (D30) — registering the new key; the hub re-keys the peer in place and the endpoint takes the new key",
+		"old_pubkey", pub, "new_pubkey", newPub, "future_s", fut)
+	m.nextRegAt = time.Time{} // register now, not after an older backoff
+	m.registerLocked(ctx, newPub)
+	return true
+}
+
+// rotateKey makes a new key pair, never leaving the box without a readable key (review 2026-10-23 night, N6): the new
+// key is written and fsynced to a temp file; the current key gets a second name by a HARD LINK (the escrow may hold
+// it — `private.key.prev` keeps the first such key, later ones `private.key.prev.<unix>`, the newest three kept, N7);
+// then the temp file is renamed OVER the current name (atomic) and the directory fsynced. At every instant
+// `private.key` is a complete key. Returns the new PUBLIC key only.
+func rotateKey(stateDir string) (string, error) {
+	dir := filepath.Join(stateDir, "wg")
+	cur := filepath.Join(dir, keyFileName)
+	if _, err := os.Stat(cur); err != nil {
+		return "", fmt.Errorf("no current key: %w", err)
+	}
+	priv := make([]byte, 32)
+	if _, err := rand.Read(priv); err != nil {
+		return "", fmt.Errorf("entropy: %w", err)
+	}
+	clampPrivateKey(priv)
+	pub, err := derivePublic(priv)
+	if err != nil {
+		return "", err
+	}
+	tmp := filepath.Join(dir, keyFileName+".new")
+	f, err := os.OpenFile(tmp, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0o600)
+	if err != nil {
+		return "", fmt.Errorf("writing the new key: %w", err)
+	}
+	_, werr := f.Write([]byte(base64.StdEncoding.EncodeToString(priv) + "\n"))
+	serr := f.Sync()
+	cerr := f.Close()
+	if werr != nil || serr != nil || cerr != nil {
+		os.Remove(tmp)
+		return "", fmt.Errorf("writing the new key: %v %v %v", werr, serr, cerr)
+	}
+	prev := filepath.Join(dir, prevKeyName)
+	if _, err := os.Lstat(prev); err == nil {
+		prev = filepath.Join(dir, fmt.Sprintf("%s.%d", prevKeyName, rekeyNow().Unix()))
+	}
+	if err := os.Link(cur, prev); err != nil {
+		os.Remove(tmp)
+		return "", fmt.Errorf("keeping the old key: %w", err)
+	}
+	if err := os.Rename(tmp, cur); err != nil {
+		os.Remove(tmp)
+		return "", fmt.Errorf("installing the new key: %w", err)
+	}
+	if d, err := os.Open(dir); err == nil {
+		d.Sync()
+		d.Close()
+	}
+	prunePrevKeys(dir, 3)
+	return pub, nil
+}
+
+// rekeyNow is the clock for the kept-key names (a seam).
+var rekeyNow = time.Now
+
+// prunePrevKeys keeps the newest `keep` of the `private.key.prev.<unix>` files (`private.key.prev` itself always stays).
+func prunePrevKeys(dir string, keep int) {
+	m, _ := filepath.Glob(filepath.Join(dir, prevKeyName+".*"))
+	if len(m) <= keep {
+		return
+	}
+	sort.Strings(m) // the same digit count until 2286: lexical = time order
+	for _, p := range m[:len(m)-keep] {
+		os.Remove(p)
+	}
+}
+
+// lastRekeyFile records the last re-key's time across agent restarts (N7: the once-an-hour bound was in memory only).
+const lastRekeyFile = "last-rekey"
+
+func (m *Manager) loadLastRekey() time.Time {
+	b, err := os.ReadFile(filepath.Join(m.wgDir(), lastRekeyFile))
+	if err != nil {
+		return time.Time{}
+	}
+	var u int64
+	if _, err := fmt.Sscanf(strings.TrimSpace(string(b)), "%d", &u); err != nil {
+		return time.Time{}
+	}
+	return time.Unix(u, 0)
+}
+
+func (m *Manager) saveLastRekey(t time.Time) {
+	_ = os.WriteFile(filepath.Join(m.wgDir(), lastRekeyFile), []byte(fmt.Sprintf("%d\n", t.Unix())), 0o600)
+}

internal/wgtunnel/rekey_test.go

@@ -0,0 +1,227 @@
+package wgtunnel
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+// D30 (R-1204): a handshake stamped in the future that STAYS for rekeyAfter → a new key pair, registered on the
+// existing peer path (the hub re-keys in place; its full-list push to ep0 swaps the key). The fake `wg` reports a
+// handshake at 1783107115; a clock three hours behind that sees it three hours in the future.
+// RED-PROOF (2026-10-22 night): with the clockAheadRekeyLocked call removed from Watchdog,
+// TestD30_AFutureHandshakeThatStaysReKeys and …AFailedRegistration… fail (no new key, no registration); with the
+// rekeyAfter wait removed, …ThatStaysReKeys fails (a re-key at 10 min); with the isActive check removed,
+// TestD30_NoReKeyWhileTheTunnelIsDown fails.
+
+const hs = 1783107115
+
+func at(m *Manager, unix int64) { m.now = func() time.Time { return time.Unix(unix, 0) } }
+
+func readKey(t *testing.T, m *Manager, name string) string {
+	t.Helper()
+	b, err := os.ReadFile(filepath.Join(m.stateDir, "wg", name))
+	if err != nil {
+		t.Fatal(err)
+	}
+	return strings.TrimSpace(string(b))
+}
+
+func TestD30_AFutureHandshakeThatStaysReKeys(t *testing.T) {
+	fh := &fakeHub{}
+	m, _, active, logs := testManager(t, fh)
+	oldPub := establishWG(t, m, active)
+	oldPriv := readKey(t, m, keyFileName)
+	ctx := context.Background()
+	calls := fh.count()
+
+	t0 := int64(hs - 3*3600) // the clock is right again; the last handshake (made while it ran ahead) is 3 h ahead
+	at(m, t0)
+	m.Watchdog(ctx, true, testBlock(oldPub))
+	at(m, t0+10*60)
+	m.Watchdog(ctx, true, testBlock(oldPub))
+	if fh.count() != calls || localPub(t, m) != oldPub {
+		t.Fatal("no re-key before the future stamp has stayed rekeyAfter")
+	}
+	at(m, t0+16*60)
+	m.Watchdog(ctx, true, testBlock(oldPub))
+	newPub := localPub(t, m)
+	if newPub == oldPub {
+		t.Fatal("a future stamp that stayed 16 min must give a new key")
+	}
+	if fh.count() != calls+1 {
+		t.Fatalf("the new key must be registered on the existing peer path (RegisterWG calls %d → %d)", calls, fh.count())
+	}
+	if mk := m.loadMarker(); mk == nil || mk.Pubkey != newPub {
+		t.Fatalf("the registration marker must carry the new key: %+v", mk)
+	}
+	if readKey(t, m, prevKeyName) != oldPriv {
+		t.Fatal("the old private key must be kept as private.key.prev (the escrow may hold it)")
+	}
+	if strings.Contains(logs.String(), oldPriv) || strings.Contains(logs.String(), readKey(t, m, keyFileName)) {
+		t.Fatal("a private key reached the log")
+	}
+	// The served block still names the OLD key until the next fetch: no second re-key over that.
+	at(m, t0+17*60)
+	m.Watchdog(ctx, true, testBlock(oldPub))
+	if localPub(t, m) != newPub {
+		t.Fatal("a second re-key ran before the hub served the new key")
+	}
+	// The hub serves the new key → the tunnel is applied with the NEW private key.
+	m.Apply(ctx, true, testBlock(newPub))
+	conf, err := os.ReadFile(m.stagedConfPath())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(string(conf), readKey(t, m, keyFileName)) || strings.Contains(string(conf), oldPriv) {
+		t.Fatal("the applied tunnel must use the new private key, not the old one")
+	}
+}
+
+func TestD30_AShortFutureSpellDoesNotReKey(t *testing.T) {
+	fh := &fakeHub{}
+	m, _, active, _ := testManager(t, fh)
+	pub := establishWG(t, m, active)
+	ctx := context.Background()
+	t0 := int64(hs - 3*3600)
+	at(m, t0)
+	m.Watchdog(ctx, true, testBlock(pub))
+	at(m, hs+100) // a handshake now lies in the past: the sign ended (a working tunnel)
+	m.Watchdog(ctx, true, testBlock(pub))
+	at(m, t0+20*60) // in the future again: a NEW window starts, it does not continue the old one
+	m.Watchdog(ctx, true, testBlock(pub))
+	if localPub(t, m) != pub {
+		t.Fatal("a future stamp that did not STAY for rekeyAfter must not re-key")
+	}
+}
+
+func TestD30_NoReKeyWhileTheTunnelIsDown(t *testing.T) {
+	fh := &fakeHub{}
+	m, _, active, _ := testManager(t, fh)
+	pub := establishWG(t, m, active)
+	*active = false
+	ctx := context.Background()
+	t0 := int64(hs - 3*3600)
+	for _, d := range []int64{0, 20 * 60, 40 * 60} {
+		at(m, t0+d)
+		m.Watchdog(ctx, true, testBlock(pub))
+	}
+	if localPub(t, m) != pub {
+		t.Fatal("no re-key while the tunnel unit is not active")
+	}
+}
+
+func TestD30_AFailedRegistrationIsRetriedByTheExistingPath(t *testing.T) {
+	fh := &fakeHub{}
+	m, _, active, _ := testManager(t, fh)
+	oldPub := establishWG(t, m, active)
+	ctx := context.Background()
+	t0 := int64(hs - 3*3600)
+	at(m, t0)
+	m.Watchdog(ctx, true, testBlock(oldPub))
+	fh.mu.Lock()
+	fh.err = errors.New("hub down")
+	fh.mu.Unlock()
+	at(m, t0+16*60)
+	m.Watchdog(ctx, true, testBlock(oldPub))
+	newPub := localPub(t, m)
+	if newPub == oldPub {
+		t.Fatal("the key rotates before the registration")
+	}
+	if mk := m.loadMarker(); mk == nil || mk.Pubkey != oldPub {
+		t.Fatal("a failed registration leaves the marker on the old key")
+	}
+	fh.mu.Lock()
+	fh.err = nil
+	fh.mu.Unlock()
+	at(m, t0+30*60) // past the backoff: Apply sees the served (old) key ≠ the local key → re-key-in-place registers
+	m.Apply(ctx, true, testBlock(oldPub))
+	if mk := m.loadMarker(); mk == nil || mk.Pubkey != newPub {
+		t.Fatalf("the existing re-key-in-place path must register the new key: %+v", mk)
+	}
+}
+
+// Review 2026-10-23 night. N7: a second rotation keeps the FIRST old key as `private.key.prev` (the escrow may hold it)
+// and the later one beside it; N6: the current key is replaced by a rename OVER it, so `private.key` is never missing.
+// RED-PROOF: with the „prev exists → a dated name" branch removed, TwoRotations fails (the first key overwritten) —
+// seen failing 2026-10-23 night.
+func TestD30_TwoRotationsKeepTheFirstOldKey(t *testing.T) {
+	fh := &fakeHub{}
+	m, _, active, _ := testManager(t, fh)
+	establishWG(t, m, active)
+	first := readKey(t, m, keyFileName)
+	old := rekeyNow
+	defer func() { rekeyNow = old }()
+	rekeyNow = func() time.Time { return time.Unix(hs, 0) }
+	if _, err := rotateKey(m.stateDir); err != nil {
+		t.Fatal(err)
+	}
+	second := readKey(t, m, keyFileName)
+	rekeyNow = func() time.Time { return time.Unix(hs+7200, 0) }
+	if _, err := rotateKey(m.stateDir); err != nil {
+		t.Fatal(err)
+	}
+	if readKey(t, m, prevKeyName) != first {
+		t.Fatal("private.key.prev must keep the FIRST old key")
+	}
+	if readKey(t, m, fmt.Sprintf("%s.%d", prevKeyName, hs+7200)) != second {
+		t.Fatal("the second old key must be kept beside it")
+	}
+	if cur := readKey(t, m, keyFileName); cur == first || cur == second {
+		t.Fatal("the current key must be new")
+	}
+}
+
+// N7: the once-an-hour bound survives an agent restart (it was in memory only). RED-PROOF: with loadLastRekey removed
+// from clockAheadRekeyLocked, this fails — seen failing 2026-10-23 night.
+func TestD30_TheHourBoundSurvivesARestart(t *testing.T) {
+	fh := &fakeHub{}
+	m, rr, active, _ := testManager(t, fh)
+	pub := establishWG(t, m, active)
+	ctx := context.Background()
+	t0 := int64(hs - 3*3600)
+	at(m, t0)
+	m.Watchdog(ctx, true, testBlock(pub))
+	at(m, t0+16*60)
+	m.Watchdog(ctx, true, testBlock(pub))
+	newPub := localPub(t, m)
+	if newPub == pub {
+		t.Fatal("fixture: the first re-key must happen")
+	}
+	// The agent restarts: a NEW manager on the same state; the served block now names the new key; the sign is back.
+	m2 := NewManager(rr, fh, m.stateDir, m.logger)
+	m2.isActive, m2.wgPresent, m2.resolver = m.isActive, m.wgPresent, m.resolver
+	m2.Apply(ctx, true, testBlock(newPub))
+	at(m2, t0+20*60)
+	m2.Watchdog(ctx, true, testBlock(newPub))
+	at(m2, t0+40*60)
+	m2.Watchdog(ctx, true, testBlock(newPub))
+	if localPub(t, m2) != newPub {
+		t.Fatal("a restart must not reset the once-an-hour bound")
+	}
+	_ = active
+}
+
+// Commit security review 2026-10-23 night: a last re-key saved while the clock ran ahead (a later date than now) must
+// not block the next re-key until that date. RED-PROOF: with the „lastRekey after now → dropped" guard removed, this
+// fails — seen failing 2026-10-23 night.
+func TestD30_ALastReKeyFromTheFutureDoesNotBlock(t *testing.T) {
+	fh := &fakeHub{}
+	m, _, active, _ := testManager(t, fh)
+	pub := establishWG(t, m, active)
+	m.saveLastRekey(time.Unix(hs+2*365*86400, 0)) // written while the clock was two years ahead
+	ctx := context.Background()
+	t0 := int64(hs - 3*3600)
+	at(m, t0)
+	m.Watchdog(ctx, true, testBlock(pub))
+	at(m, t0+16*60)
+	m.Watchdog(ctx, true, testBlock(pub))
+	if localPub(t, m) == pub {
+		t.Fatal("a last re-key dated in the future must not block the re-key")
+	}
+}