git.stella-ops.org/docs/provenance/inline-dsse.md

Inline DSSE Provenance

Status: Draft – aligns with the November 2025 advisory “store DSSE attestation refs inline on every SBOM/VEX event node.”
Owners: Authority Guild · Feedser Guild · Platform Guild · Docs Guild.

This document defines how Stella Ops records provenance for SBOM, VEX, scan, and derived events: every event node in the Mongo event graph includes DSSE + Rekor references and verification metadata so audits and replay become first-class queries.

---

1. Event patch (Mongo schema)

{
  "_id": "evt_...",
  "kind": "SBOM|VEX|SCAN|INGEST|DERIVED",
  "subject": {
    "purl": "pkg:nuget/example@1.2.3",
    "digest": { "sha256": "..." },
    "version": "1.2.3"
  },
  "provenance": {
    "dsse": {
      "envelopeDigest": "sha256:...",
      "payloadType": "application/vnd.in-toto+json",
      "key": {
        "keyId": "cosign:SHA256-PKIX:ABC...",
        "issuer": "fulcio",
        "algo": "ECDSA"
      },
      "rekor": {
        "logIndex": 1234567,
        "uuid": "b3f0...",
        "integratedTime": 1731081600,
        "mirrorSeq": 987654   // optional
      },
      "chain": [
        { "type": "build", "id": "att:build#...", "digest": "sha256:..." },
        { "type": "sbom",  "id": "att:sbom#...",  "digest": "sha256:..." }
      ]
    }
  },
  "trust": {
    "verified": true,
    "verifier": "Authority@stella",
    "witnesses": 1,
    "policyScore": 0.92
  },
  "ts": "2025-11-11T12:00:00Z"
}

Key fields

Field	Description
provenance.dsse.envelopeDigest	SHA-256 of the DSSE envelope (not payload).
provenance.dsse.payloadType	Usually application/vnd.in-toto+json.
provenance.dsse.key	Key fingerprint / issuer / algorithm.
provenance.dsse.rekor	Rekor transparency log metadata (index, UUID, integrated time).
provenance.dsse.chain	Optional chain of dependent attestations (build → sbom → scan).
trust.*	Result of local verification (DSSE signature, Rekor proof, policy).

---

2. Write path (ingest flow)

1. Obtain provenance metadata for each attested artifact (build, SBOM, VEX, scan). The CI script (scripts/publish_attestation_with_provenance.sh) captures envelopeDigest, Rekor logIndex/uuid, and key info.
2. Authority/Feedser verify the DSSE + Rekor proof (local cosign/rekor libs or the Signer service) and set trust.verified = true, trust.verifier = "Authority@stella", trust.witnesses = 1.
3. Attach the provenance block before appending the event to Mongo, using StellaOps.Provenance.Mongo helpers.
4. Backfill historical events by resolving known subjects → attestation digests and running an update script.

2.1 Supplying metadata from Concelier statements

Concelier ingestion jobs can now inline provenance when they create advisory statements. Add an AdvisoryProvenance entry with kind = "dsse" (or dsse-metadata / attestation-dsse) and set value to the same JSON emitted by the CI snippet. AdvisoryEventLog and AdvisoryMergeService automatically parse that entry, hydrate AdvisoryStatementInput.Provenance/Trust, and persist the metadata alongside the statement.

{
  "source": "attestor",
  "kind": "dsse",
  "value": "{ \"dsse\": { \"envelopeDigest\": \"sha256:…\", \"payloadType\": \"application/vnd.in-toto+json\" }, \"trust\": { \"verified\": true, \"verifier\": \"Authority@stella\" } }",
  "recordedAt": "2025-11-10T00:00:00Z"
}

Providing the metadata during ingestion keeps new statements self-contained and reduces the surface that the /events/statements/{statementId}/provenance endpoint needs to backfill later.

Reference helper: src/__Libraries/StellaOps.Provenance.Mongo/ProvenanceMongoExtensions.cs.

---

3. CI/CD snippet

See scripts/publish_attestation_with_provenance.sh:

rekor-cli upload --rekor_server "$REKOR_URL" \
  --artifact "$ATTEST_PATH" --type dsse --format json > rekor-upload.json
LOG_INDEX=$(jq '.LogIndex' rekor-upload.json)
UUID=$(jq -r '.UUID' rekor-upload.json)
ENVELOPE_SHA256=$(sha256sum "$ATTEST_PATH" | awk '{print $1}')
cat > provenance-meta.json <<EOF
{
  "subject": { "imageRef": "$IMAGE_REF", "digest": { "sha256": "$IMAGE_DIGEST" } },
  "dsse": {
    "envelopeDigest": "sha256:$ENVELOPE_SHA256",
    "payloadType": "application/vnd.in-toto+json",
    "key": { "keyId": "$KEY_ID", "issuer": "$KEY_ISSUER", "algo": "$KEY_ALGO" },
    "rekor": { "logIndex": $LOG_INDEX, "uuid": "$UUID", "integratedTime": $(jq '.IntegratedTime' rekor-upload.json) }
  }
}
EOF

Feedser ingests this JSON and maps it to DsseProvenance + TrustInfo.

---

4. Mongo indexes

Create indexes to keep provenance queries fast (mongosh):

db.events.createIndex(
  { "subject.digest.sha256": 1, "kind": 1, "provenance.dsse.rekor.logIndex": 1 },
  { name: "events_by_subject_kind_provenance" }
);

db.events.createIndex(
  { "kind": 1, "trust.verified": 1, "provenance.dsse.rekor.logIndex": 1 },
  { name: "events_unproven_by_kind" }
);

db.events.createIndex(
  { "provenance.dsse.rekor.logIndex": 1 },
  { name: "events_by_rekor_logindex" }
);

Corresponding C# helper: MongoIndexes.EnsureEventIndexesAsync.

---

5. Query recipes

• All proven VEX for an image digest:

db.events.find({
  kind: "VEX",
  "subject.digest.sha256": "<digest>",
  "provenance.dsse.rekor.logIndex": { $exists: true },
  "trust.verified": true
})

• Compliance gap (unverified data used for decisions):

db.events.aggregate([
  { $match: { kind: { $in: ["VEX","SBOM","SCAN"] } } },
  { $match: {
      $or: [
        { "trust.verified": { $ne: true } },
        { "provenance.dsse.rekor.logIndex": { $exists: false } }
      ]
    }
  },
  { $group: { _id: "$kind", count: { $sum: 1 } } }
])

• Replay slice: filter for events where provenance.dsse.chain covers build → sbom → scan and export referenced attestation digests.

---

6. Policy gates

Examples:

rules:
  - id: GATE-PROVEN-VEX
    when:
      all:
        - kind: "VEX"
        - trust.verified: true
        - key.keyId in VendorAllowlist
        - rekor.integratedTime <= releaseFreeze
    then:
      decision: ALLOW

  - id: BLOCK-UNPROVEN
    when:
      any:
        - trust.verified != true
        - provenance.dsse.rekor.logIndex missing
    then:
      decision: FAIL
      reason: "Unproven evidence influences decision; require Rekor-backed attestation."

---

7. UI nudges

• Provenance chip on findings/events: Verified • Rekor#1234567 • KeyID:cosign:... (click → inclusion proof & DSSE preview).
• Facet filter: Provenance = Verified / Missing / Key-Policy-Mismatch.

---

8. Implementation tasks

Task ID	Scope
PROV-INLINE-401-028	Extend Authority/Feedser write-paths to attach provenance.dsse + trust blocks using StellaOps.Provenance.Mongo.
PROV-BACKFILL-401-029	Backfill historical events with DSSE/Rekor refs based on existing attestation digests.
PROV-INDEX-401-030	Create Mongo indexes and expose helper queries for audits.

Keep this document updated when new attestation types or mirror/witness policies land.

---

9. Feedser API for provenance updates

Feedser exposes a lightweight endpoint for attaching provenance after an event is recorded:

POST /events/statements/{statementId}/provenance
Headers: X-Stella-Tenant, Authorization (if Authority is enabled)
Body: { "dsse": { ... }, "trust": { ... } }

The body matches the JSON emitted by publish_attestation_with_provenance.sh. Feedser validates the payload, ensures trust.verified = true, and then calls AttachStatementProvenanceAsync so the DSSE metadata lands inline on the target statement. Clients receive HTTP 202 on success, 400 on malformed input, and 404 if the statement id is unknown.