Second bench defect after removing the distro 20-chrony-dhcp clobberer
(secure-ntp-5a3eaed, comet-beacon-54): the dispatcher wrote the correct
`server ntp.fleet.lab iburst nts` line, but chrony loaded ZERO sources --
`chronyc reload sources` returned 200 OK yet authdata/sources stayed empty.
Root cause (AVC): chronyd_t was DENIED read on the .sources files because they and
/run/chrony-dhcp itself were labeled generic var_run_t; chronyd_t may only read its
own chronyd_var_run_t. The dispatcher's `mkdir -p` creates the dir as var_run_t and
files inherit it. The distro 20-chrony-dhcp we removed had been restorecon-ing them
to the readable label, so removing it exposed a latent labelling gap.
Stock RHEL policy already maps /run/chrony-dhcp -> chronyd_var_run_t (a restorecon
relabels it and chrony immediately reaches NTS Cook 8). Fix: ship
/etc/tmpfiles.d/chrony-dhcp.conf so systemd-tmpfiles pre-creates the dir with that
fcontext at sysinit, before any NM event -- the dispatcher's files then inherit
chronyd_var_run_t and chronyd can read them. No SELinux allow rules needed
(bench-verified: after the fix a real NM event wrote the source as chronyd_var_run_t,
no AVC, authdata -> NTS Cook 8). Applies in both secure_ntp modes.
Also: the dispatcher now skips `lo` -- it was writing a spurious lo.sources
duplicate of the same server (the distro script had skipped loopback).
BENCH-VERIFY on the next clean build: a normal boot leaves the source file labeled
chronyd_var_run_t (ls -Z), no lo.sources, and authdata reaches NTS/cookies>0 with no
manual step.
NTS was inactive on the clean-build deploy (secure-ntp-d1621e9, comet-beacon-54):
chronyc authdata showed a plain IP source in Mode '-', Cook 0, with no NTS-KE
attempt at all -- chrony was on plain NTP.
Root cause: NetworkManager runs dispatcher scripts from BOTH
/etc/NetworkManager/dispatcher.d and /usr/lib/NetworkManager/dispatcher.d, merged
and sorted by filename. The chrony RPM ships
/usr/lib/NetworkManager/dispatcher.d/20-chrony-dhcp, which writes the DHCP
option-42 server to the SAME /run/chrony-dhcp/<iface>.sources file our
10-chrony-dhcp-ntp uses. Sorting after 10-, it ran last and overwrote our
`server ntp.fleet.lab iburst nts` line with `server 192.168.50.10 iburst`, then
reloaded chrony -- last writer wins on the shared filename, silently defeating
authenticated time.
Isolation proof: removing the distro script + hand-writing the NTS source brought
NTS up immediately (ntp.fleet.lab NTS, Cook 8, zero NAKs), confirming the host
image, the fleet-signed NTS-KE cert, DNS, and tcp/4460 were all already correct --
the collision was the sole defect.
Fix: the provisioner removes /usr/lib/NetworkManager/dispatcher.d/20-chrony-dhcp
at build (our dispatcher supersedes it in both modes); 20-chrony-onoffline is left
in place (harmless). Documents the finding in the dispatcher header,
docs/secure-ntp-design.md, and the CLAUDE.md secure_ntp note. BENCH-VERIFY on the
next clean build: a normal boot reaches NTS/cookies>0 with no manual step.
NTS proven end-to-end on comet-beacon-54 (chronyc authdata cookies > 0); these
close the gaps the bench found so a clean build/serving run reaches that state
without manual patching:
- dispatcher (10-chrony-dhcp-ntp): fall back to resolv.conf search/domain when NM
doesn't export DHCP4_DOMAIN_NAME on the firing event, so the NTS source is
written reliably at boot (tonight it needed a manual dispatcher run).
- STIG vs secure_ntp (P2, security): STIG's chronyd_specify_remote_server re-injects
an UNAUTHENTICATED 'server 0.us.pool.ntp.mil maxpoll 16' AFTER the secure_ntp
chrony step commented servers out -> a silent fallback that defeats NTS's
DoS-only guarantee (host not fail-closed). Unselect chronyd_specify_remote_server
+ chronyd_or_ntpd_set_maxpoll in diskless-tailoring.xml, and re-strip any
server/pool in 2c-STIG-postfix when secure_ntp=true. Documented: stig-deviations #17.
- nts-cert.sh (P3): the container's chrony user (non-root) can't read a 0640
host-owned key -> NTS-KE TLS aborts ('non-properly terminated'). chown the key to
the ntp container's chrony uid + keep 0640 (0644 works but chrony warns
world-readable); 0644 fallback if the uid can't be found.
Bench-verified 2026-07-11; docs updated in docs/ssh-host-certificate-design.md's
sibling secure-ntp-design.md flow. F-03/P-18 stays open until a clean build shows
chrony.conf has no plain server and authdata cookies>0 as the only source.
First trim build confirmed firmware 678 MB -> 147 MB, but the initramfs came
out 97 MB and is now kernel-MODULE-bound, not firmware: --no-hostonly +
plymouth's drm dep instmods every GPU driver (amdgpu.ko etc.) though the fleet
is i915-only.
- omit_drivers += amdgpu radeon nouveau (90-diskless.conf): drop the discrete-GPU
kmods (amdgpu.ko is the biggest single module in the initramfs); keep i915 +
virtio-gpu/bochs for the splash. Shrinks the initramfs/UKI pulled over PXE on
every boot.
- Firmware keep-list tightened: drop mellanox/ (mlxsw_spectrum SWITCH-ASIC blobs,
not NIC fw — mlx5 NIC fw is on-card) and narrow intel/ to just ice (drop
ish/sof/ibt sensor-hub/audio/bluetooth, none loaded at boot per the audit).
- Add an 'initramfs largest files' diagnostic (sort lsinitrd.txt by size) so the
next build shows what dominates the .img.
BENCH-VERIFY: kiosk still renders on the 820 (i915 kept); watch the new initramfs
largest-files log line for the post-omit size.
Bench (Proxmox vTPM, host cygnus-cruiser-99) confirmed via tpm2_readpublic that
0x81010001 — the handle our design used for the fleet signing key — is the
TCG-standard RSA Endorsement Key slot: the object there is the swtpm-provisioned
EK (restricted|decrypt|adminwithpolicy, RSA-2048/AES128CFB, canonical EK
authPolicy 837197…, EK cert at NV 0x1c00002). Most firmware/swtpm TPMs occupy
that slot, so EnsureKey could never create our key there — it errored reading
the EK as ECC and enrolment died before the CSR/POST.
Move the fleet signing key to 0x81000100, a non-reserved owner persistent
handle (clear of EK 0x81010001/2 and SRK 0x81000001/2). Threaded through:
- fleet-enrol -handle default + new rd.dot1x.handle= cmdline knob (baked by
extract-artifacts.sh, overridable via SMBIOS)
- files/etc/dot1x/wpa_supplicant-dot1x.conf private_key handle
- the dracut hook, bench tpm-provision.sh / tpm-selftest.sh
- CLAUDE.md invariant #1 + design/SSP docs + TODO #11
NV index 0x01800001 (owner range) is unchanged.
EnsureKey hardening: refuse to evict any restricted-decrypt object (EK/SRK) as
a safety net — never clobber the TPM endorsement/storage identity (also
protects the future EK/AK attestation path). Still self-heals a genuine stale
signing key. New regression TestEnsureKeyRefusesToEvictProtectedKey; the
stale-key regression and handle constants moved to 0x81000100.
Design note records the IDevID (0x81020001) option for the later EK/AK
attestation work. Follow-up items logged: content-aware NV presence check
(verify the cert chains to the fleet CA, so leftover/foreign NV can't suppress
enrolment) and a de-enrol/TPM-reset procedure.
Audiobuzz