confidential-attestation

ugallu-confidential-attestation answers “is this node what it claims to be?” - a per-node DaemonSet generates a hardware-rooted quote, the controller verifies it against a configured policy, and the result is sealed by the attestor for downstream consumption.

Per-node dispatch

Unlike the other ugallu operators, this one runs without leader election because each node must reconcile runs targeted at itself. The reconciler filters cluster-wide on spec.targetNodeName == os.Getenv("NODE_NAME") and skips everything else - so 100 nodes producing 100 quotes is 100 independent reconciles, no coordination.

Backends

Backend	What it produces
tpm	TPM 2.0 quote over PCR 0–7 using go-tpm-tools client.AttestationKeyECC. The quote includes the TPM-signed PCR digest + nonce.
sev-snp	AMD SEV-SNP attestation report from /dev/sev-guest. Used on confidential VMs.
tdx	Intel TDX attestation report from /dev/tdx-guest. Used on TDX-enabled hosts.

Missing or unreadable devices fail the run with a structured reason

• there is no fallback to a software-emulated quote.

Verification policy

ConfidentialAttestationRun.spec.policy declares the expected PCR values / SEV-SNP IDBlock / TDX MRTD. The controller compares the quote against the policy and emits:

• AttestationVerified (Compliance class) on match
• AttestationFailed (Detection class, severity=critical) on mismatch or device error

Example

apiVersion: security.ugallu.io/v1alpha1
kind: ConfidentialAttestationRun
metadata: { name: bootcheck-node1, namespace: ugallu-system }
spec:
  backend: tpm
  targetNodeName: node1.example.internal
  policy:
    tpm:
      pcrs:
        "0": "ab12...c3"
        "7": "ee45...77"
  timeout: 30s

Internals

State machine

ConfidentialAttestationRun.status.phase: “ (Pending) -> Running -> Succeeded | Failed. No finalizer. Per-node scoping: a DaemonSet pod skips the run if run.Spec.TargetNodeName != os.Getenv("NODE_NAME") - so 100 nodes producing 100 quotes is 100 independent reconciles.

Reconcile loop

on each ConfidentialAttestationRun event:
  run := Get(req)
  if run.Spec.TargetNodeName != myNodeName: return  # not for me
  if run.Status.Phase in {Succeeded, Failed}: return
  if run.Status.Phase == "":
    patch Status.Phase=Running, StartTime=now
    emitSE(AttestationStarted, info)
    return Requeue
  attester := attesterFor(run.Spec.Backend)   # tpm | sev-snp | tdx
  outcome  := attester.Attest(ctx, run.Spec.Nonce, run.Spec.Policy)
  upsert ConfidentialAttestationResult (Verdict, Quote, Measurements)
  patch Status.Phase = (outcome.Verdict==Verified ? Succeeded : Failed)
  emitSE(AttestationVerified | AttestationFailed)

Error recovery

Restart mid-attestation: new pod re-Gets the CR (Phase=Running) and re-calls Attest(). Re-running with the same nonce is deterministic against the hardware - the quote bytes will match the earlier (lost) one. Result CR Create returns AlreadyExists on retry; the controller falls back to Update on the result and re-patches verdict. No leader election: each DaemonSet pod owns its own reconciles, no coordination needed.

Crash recovery scenario

Pod killed after Attest() returns but before the Result CR is written: the new pod re-Gets the run, re-runs Attest() (idempotent against the same nonce), creates the Result CR. The hardware never produces conflicting quotes for the same nonce, so the second run agrees with the first.

Edge cases

• Indeterminate verdicts (e.g. policy says expected PCR but the verifier can’t read the device) are emitted as AttestationVerified at info severity with notes in verifier.notes; the run is still Succeeded so dashboards see a result.
• Software-emulated quotes are not allowed. Missing or unreadable hardware devices fail the run with a structured reason; there is no fallback.
• Per-node DaemonSet runs in ugallu-system-privileged with priorityClassName: system-node-critical to survive node pressure.

Full RBAC (ClusterRole)

rules:
  - apiGroups: [security.ugallu.io]
    resources:
      - confidentialattestationruns
      - confidentialattestationruns/status
      - confidentialattestationresults
      - confidentialattestationresults/status
    verbs: [get, list, watch, create, update, patch]
  - apiGroups: [security.ugallu.io]
    resources: [securityevents]
    verbs: [create]
  - apiGroups: [""]
    resources: [events]
    verbs: [create, patch]

No leases (no leader election).

CRDs owned

• ConfidentialAttestationRun
  • per-run, per-node.
• ConfidentialAttestationResult
  • quote bytes + verifier verdict.

Key flags

--cluster-id, --cluster-name, --node-name (defaults to NODE_NAME env), --tpm-device, --sev-snp-device, --tdx-device.

Deployment

DaemonSet in ugallu-system-privileged, priorityClassName=system-node-critical, leader election off. Mounts the hardware device hostPaths read-only. Each pod reconciles only its own node’s runs.