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jakman85andClaude Opus 5 ab9ba32a76 feat(sec): bake conformance-clone so the init container has no injection surface

Closes half of the admission gap a sibling agent found in PR #13's policy: it pins
the MAIN container's `command` but never reads `initContainers`, so a Job from
`conformance-trigger` can carry an init container with `command: ["/bin/sh","-c"]`
and an arbitrary script, running as the privileged `conformance-runner` SA.
Reproduced by the policy's author: pass 3, fail 0 on a privileged alpine:latest
init container running `kubectl get secrets -A`.

The image now carries /usr/local/bin/conformance-clone, 0755 root:root, so uid
65532 cannot replace the one executable the policy will come to trust. Clone logic
taken from PR #20's `clone-suite-at-commit`, with both load-bearing properties
preserved: the SHA must match ^[0-9a-f]{40}$, and `rev-parse HEAD` is ASSERTED
equal to it after checkout, so an unrendered placeholder is a hard failure instead
of a silent run of the branch tip. No arguments are accepted.

DEVIATION FROM THE BRIEF, DELIBERATE: the repo URL and clone target are COMPILED
IN rather than read from the environment. I was asked to take SHA, repo URL and
target dir from env. The policy contains no `env`/`valueFrom`/`secretKeyRef` clause
at all -- so trusting CONFORMANCE_REPO_URL would move the injection one field over:
the trigger points it at a repo it controls, this fetches that, and ./run.sh from
the attacker's tree runs under the privileged SA. "No args" would not have stopped
it. The env vars are still read so the Job template stays self-documenting, but a
value disagreeing with the baked literal is a hard failure, never a redirect. The
SHA is the only genuinely trusted per-run input.

THIS IS HALF A FIX. What makes the fixed path REQUIRED rather than merely available
is a 4th policy rule demanding command: ["/usr/local/bin/conformance-clone"] with
no args on every initContainer. That edits the security boundary and belongs in its
own reviewed PR -- it is NOT here. Until it lands the hole is open, and the README,
the Containerfile and the script header all say so.

VERIFIED by running it (uid 65532, --read-only): root:root 755 and confirmed not
writable by the runner; seven negative cases each asserted to exit non-zero
(arguments, missing SHA, a branch name, an unrendered @@placeholder@@, HOME off the
workspace volume, a REDIRECTED repo URL, a clone target off the workspace volume);
and the positive case -- a real clone of this repo at a real 40-hex SHA with
rev-parse HEAD proven equal to it.

Two bugs of mine that only running it could find, both fixed: the workspace-path
guard matched /workspace/* and so rejected the image's own HOME=/workspace; and the
negative checks were pipelines, which under pipefail aborted the verify at the
first expected failure and silently skipped the other six. A verify that stops
early looks exactly like a verify that passed.

The anonymous-clone fallback is deliberate and logged: read access to this repo
needs no credential today, the integrity guarantee is the SHA assertion rather than
the credential, and requiring the Secret would make the script untestable without
one.

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

2026-09-29 22:49:34 -05:00

build-image.sh

feat(sec): bake conformance-clone so the init container has no injection surface

2026-09-29 22:49:34 -05:00

chainsaw-job.yaml

T-0.4 Chainsaw conformance harness + coverage + behavior scaffolds (R-TEST-01..06)

2026-08-16 00:08:32 -05:00

conformance-clone

feat(sec): bake conformance-clone so the init container has no injection surface

2026-09-29 22:49:34 -05:00

Containerfile

feat(sec): bake conformance-clone so the init container has no injection surface

2026-09-29 22:49:34 -05:00

kustomization.yaml

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

2026-09-29 03:22:41 -05:00

rbac.yaml

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

2026-09-29 03:22:41 -05:00

README.md

feat(sec): bake conformance-clone so the init container has no injection surface

2026-09-29 22:49:34 -05:00

README.md

In-cluster conformance Job (L2/L3)

STATUS NOTE (2026-09-29) — read before trusting the "Phase 0" framing below. This document speaks as though no cluster exists and the platform is scaffolding. A three-node k3s cluster has existed for weeks and Flux has been reconciling against it. Gitea is live, the Actions runner incluster-dind is online, and main is a protected branch. Where the text says "Phase 0", "stub", or "no cluster exists", read it as describing a live gap rather than an expected stage — most importantly, L2/L3 conformance still does not run in CI (vars.CLUSTER_AVAILABLE is unset), which is a real coverage hole, not a phase.

This mismatch is not cosmetic. A month of "the gate enforces this" claims rested on documentation rather than measurement, and main was unprotected with zero runners registered the whole time. Query the live API before asserting platform state.

Per ADR-0011 and docs/14 "Where each layer runs": L0/L1 run in CI without a cluster, but L2 behavioral and L3 fault-injection run as an in-cluster Chainsaw Job on the dev/test cluster that CI triggers and waits for. CI holds no cluster credentials — the Job's own scoped ServiceAccount does (R-SEC-02).

Files

rbac.yaml — the conformance namespace, the conformance-runner ServiceAccount, and a least-privilege ClusterRole skeleton. Rules start empty and are added — each commented with the test/requirement that needs it — only as the matching fault-injection test lands. This is a privileged test identity: never reused by workloads, its own audit item.
chainsaw-job.yaml — the Job skeleton. Single entrypoint ./run.sh; CI sets args to --requirements <touched IDs> (merge gate) or --layer all --strict-coverage (phase exit). Its image: is STALE: it still names ghcr.io/kyverno/chainsaw:v0.2.12, which (a) cannot run ./run.sh at all and (b) is DENIED at admission. The trigger renders this template per run with CONFORMANCE_RUNNER_IMAGE injected (plan §3 item 4, T-6.1b); until that lands, treat the literal image: here as a placeholder, not a pin.
Containerfile — the conformance-runner image: bash + python3 + chainsaw + kubectl + git, non-root (numeric uid 65532) and working under a read-only root filesystem. This is what the Job actually needs; the stock chainsaw image carries none of it. Versions are --build-arg-injected from infra/devcontainer/versions.env — the single source of truth — so the chainsaw/kubectl in the runner are the same pins the toolbox gate uses. Read its header before changing the Job's args: run.sh runs the selected offline L0/L1 checks for any non-offline-only selection, and those need flux/promtool/kyverno/ kustomize, which this image deliberately omits. Use --layer l2 / --layer l3.
conformance-clone — the init container's only entrypoint, baked into the image at /usr/local/bin/conformance-clone (0755 root:root, so uid 65532 cannot replace it). Clones the impl repo at the commit under test: the SHA must match ^[0-9a-f]{40}$ and rev-parse HEAD is asserted equal to it afterwards, so an unrendered placeholder is a hard failure rather than a silent run of the branch tip. It takes no arguments, and the repository URL and clone target are compiled in — see its header for why the env vars are read but may not override them.

This file is half a fix. The admission policy pins the main container's command but never reads initContainers, so an init container with command: ["/bin/sh","-c"] and an arbitrary script is currently ADMITTED and runs as the privileged conformance-runner SA. What makes this file required rather than merely available is a 4th policy rule demanding command: ["/usr/local/bin/conformance-clone"] with no args. That rule belongs in its own reviewed PR against the boundary and is not in this branch.
build-image.sh — builds the above, verifies the toolchain by running it inside the image as uid 65532 with --read-only, and prints the digest. It never pushes: it prints the exact podman push --digestfile … command for the operator instead. See conformance/versions.env CONFORMANCE_RUNNER_IMAGE for the post-push pin. --verify-clone additionally has conformance-clone really clone this repo at a real SHA and asserts the checkout matches (opt-in, because it needs the Gitea host reachable — the default verify stays offline so an air-gapped build is fully checked, not half-checked).

Flow

CI (Gitea Actions, delivered in T-6.1b) creates a Job from chainsaw-job.yaml (via a trigger with narrow rights: create Job + read its logs/status — not a broad kubeconfig).
The Job clones/loads the impl repo at the commit under test into /workspace and runs ./run.sh under conformance-runner.
run.sh runs Chainsaw over the selected tests and writes report.junit.xml + coverage/ to the results volume (/workspace/conformance/_artifacts).
CI collects those artifacts (results volume or the terminating log stream, which echoes their paths) and enforces the merge / phase-exit gate on them.

Phase 0

No cluster exists, so nothing here is applied yet. These manifests are reconciled by Flux from Phase 1+ and first exercised when L2/L3 can run (T-3.0 onward). In Phase 0 the same run.sh runs in CI's no-cluster stage and emits a skipped JUnit + the coverage report.