# component_architecture_concelier.md — **Stella Ops Concelier** (2025Q4)

> **Scope.** Implementation‑ready architecture for **Concelier**: the vulnerability ingest/normalize/merge/export subsystem that produces deterministic advisory data for the Scanner + Policy + Excititor pipeline. Covers domain model, connectors, merge rules, storage schema, exports, APIs, performance, security, and test matrices.

---

## 0) Mission & boundaries

**Mission.** Acquire authoritative **vulnerability advisories** (vendor PSIRTs, distros, OSS ecosystems, CERTs), normalize them into a **canonical model**, reconcile aliases and version ranges, and export **deterministic artifacts** (JSON, Trivy DB) for fast backend joins.

**Boundaries.**

* Concelier **does not** sign with private keys. When attestation is required, the export artifact is handed to the **Signer**/**Attestor** pipeline (out‑of‑process).
* Concelier **does not** decide PASS/FAIL; it provides data to the **Policy** engine.
* Online operation is **allowlist‑only**; air‑gapped deployments use the **Offline Kit**.

---

## 1) Topology & processes

**Process shape:** single ASP.NET Core service `StellaOps.Concelier.WebService` hosting:

* **Scheduler** with distributed locks (Mongo backed).
* **Connectors** (fetch/parse/map).
* **Merger** (canonical record assembly + precedence).
* **Exporters** (JSON, Trivy DB).
* **Minimal REST** for health/status/trigger/export.

**Scale:** HA by running N replicas; **locks** prevent overlapping jobs per source/exporter.

---

## 2) Canonical domain model

> Stored in MongoDB (database `concelier`), serialized with a **canonical JSON** writer (stable order, camelCase, normalized timestamps).

### 2.1 Core entities

**Advisory**

```
advisoryId          // internal GUID
advisoryKey         // stable string key (e.g., CVE-2025-12345 or vendor ID)
title               // short title (best-of from sources)
summary             // normalized summary (English; i18n optional)
published           // earliest source timestamp
modified            // latest source timestamp
severity            // normalized {none, low, medium, high, critical}
cvss                // {v2?, v3?, v4?} objects (vector, baseScore, severity, source)
exploitKnown        // bool (e.g., KEV/active exploitation flags)
references[]        // typed links (advisory, kb, patch, vendor, exploit, blog)
sources[]           // provenance for traceability (doc digests, URIs)
```

**Alias**

```
advisoryId
scheme              // CVE, GHSA, RHSA, DSA, USN, MSRC, etc.
value               // e.g., "CVE-2025-12345"
```

**Affected**

```
advisoryId
productKey          // canonical product identity (see 2.2)
rangeKind           // semver | evr | nvra | apk | rpm | deb | generic | exact
introduced?         // string (format depends on rangeKind)
fixed?              // string (format depends on rangeKind)
lastKnownSafe?      // optional explicit safe floor
arch?               // arch or platform qualifier if source declares (x86_64, aarch64)
distro?             // distro qualifier when applicable (rhel:9, debian:12, alpine:3.19)
ecosystem?          // npm|pypi|maven|nuget|golang|…
notes?              // normalized notes per source
```

**Reference**

```
advisoryId
url
kind                // advisory | patch | kb | exploit | mitigation | blog | cvrf | csaf
sourceTag           // e.g., vendor/redhat, distro/debian, oss/ghsa
```

**MergeEvent**

```
advisoryKey
beforeHash          // canonical JSON hash before merge
afterHash           // canonical JSON hash after merge
mergedAt
inputs[]            // source doc digests that contributed
```

**ExportState**

```
exportKind          // json | trivydb
baseExportId?       // last full baseline
baseDigest?         // digest of last full baseline
lastFullDigest?     // digest of last full export
lastDeltaDigest?    // digest of last delta export
cursor              // per-kind incremental cursor
files[]             // last manifest snapshot (path → sha256)
```

### 2.2 Product identity (`productKey`)

* **Primary:** `purl` (Package URL).
* **OS packages:** RPM (NEVRA→purl:rpm), DEB (dpkg→purl:deb), APK (apk→purl:alpine), with **EVR/NVRA** preserved.
* **Secondary:** `cpe` retained for compatibility; advisory records may carry both.
* **Image/platform:** `oci:<registry>/<repo>@<digest>` for image‑level advisories (rare).
* **Unmappable:** if a source is non‑deterministic, keep native string under `productKey="native:<provider>:<id>"` and mark **non‑joinable**.

---

## 3) Source families & precedence

### 3.1 Families

* **Vendor PSIRTs**: Microsoft, Oracle, Cisco, Adobe, Apple, VMware, Chromium…
* **Linux distros**: Red Hat, SUSE, Ubuntu, Debian, Alpine…
* **OSS ecosystems**: OSV, GHSA (GitHub Security Advisories), PyPI, npm, Maven, NuGet, Go.
* **CERTs / national CSIRTs**: CISA (KEV, ICS), JVN, ACSC, CCCS, KISA, CERT‑FR/BUND, etc.

### 3.2 Precedence (when claims conflict)

1. **Vendor PSIRT** (authoritative for their product).
2. **Distro** (authoritative for packages they ship, including backports).
3. **Ecosystem** (OSV/GHSA) for library semantics.
4. **CERTs/aggregators** for enrichment (KEV/known exploited).

> Precedence affects **Affected** ranges and **fixed** info; **severity** is normalized to the **maximum** credible severity unless policy overrides. Conflicts are retained with **source provenance**.

---

## 4) Connectors & normalization

### 4.1 Connector contract

```csharp
public interface IFeedConnector {
  string SourceName { get; }
  Task FetchAsync(IServiceProvider sp, CancellationToken ct);   // -> document collection
  Task ParseAsync(IServiceProvider sp, CancellationToken ct);   // -> dto collection (validated)
  Task MapAsync(IServiceProvider sp, CancellationToken ct);     // -> advisory/alias/affected/reference
}
```

* **Fetch**: windowed (cursor), conditional GET (ETag/Last‑Modified), retry/backoff, rate limiting.
* **Parse**: schema validation (JSON Schema, XSD/CSAF), content type checks; write **DTO** with normalized casing.
* **Map**: build canonical records; all outputs carry **provenance** (doc digest, URI, anchors).

### 4.2 Version range normalization

* **SemVer** ecosystems (npm, pypi, maven, nuget, golang): normalize to `introduced`/`fixed` semver ranges (use `~`, `^`, `<`, `>=` canonicalized to intervals).
* **RPM EVR**: `epoch:version-release` with `rpmvercmp` semantics; store raw EVR strings and also **computed order keys** for query.
* **DEB**: dpkg version comparison semantics mirrored; store computed keys.
* **APK**: Alpine version semantics; compute order keys.
* **Generic**: if provider uses text, retain raw; do **not** invent ranges.

### 4.3 Severity & CVSS

* Normalize **CVSS v2/v3/v4** where available (vector, baseScore, severity).
* If multiple CVSS sources exist, track them all; **effective severity** defaults to **max** by policy (configurable).
* **ExploitKnown** toggled by KEV and equivalent sources; store **evidence** (source, date).

---

## 5) Merge engine

### 5.1 Keying & identity

* Identity graph: **CVE** is primary node; vendor/distro IDs resolved via **Alias** edges (from connectors and Concelier’s alias tables).
* `advisoryKey` is the canonical primary key (CVE if present, else vendor/distro key).

### 5.2 Merge algorithm (deterministic)

1. **Gather** all rows for `advisoryKey` (across sources).
2. **Select title/summary** by precedence source (vendor>distro>ecosystem>cert).
3. **Union aliases** (dedupe by scheme+value).
4. **Merge `Affected`** with rules:

   * Prefer **vendor** ranges for vendor products; prefer **distro** for **distro‑shipped** packages.
   * If both exist for same `productKey`, keep **both**; mark `sourceTag` and `precedence` so **Policy** can decide.
   * Never collapse range semantics across different families (e.g., rpm EVR vs semver).
5. **CVSS/severity**: record all CVSS sets; compute **effectiveSeverity** = max (unless policy override).
6. **References**: union with type precedence (advisory > patch > kb > exploit > blog); dedupe by URL; preserve `sourceTag`.
7. Produce **canonical JSON**; compute **afterHash**; store **MergeEvent** with inputs and hashes.

> The merge is **pure** given inputs. Any change in inputs or precedence matrices changes the **hash** predictably.

---

## 6) Storage schema (MongoDB)

**Collections & indexes**

* `source` `{_id, type, baseUrl, enabled, notes}`
* `source_state` `{sourceName(unique), enabled, cursor, lastSuccess, backoffUntil, paceOverrides}`
* `document` `{_id, sourceName, uri, fetchedAt, sha256, contentType, status, metadata, gridFsId?, etag?, lastModified?}`

  * Index: `{sourceName:1, uri:1}` unique, `{fetchedAt:-1}`
* `dto` `{_id, sourceName, documentId, schemaVer, payload, validatedAt}`

  * Index: `{sourceName:1, documentId:1}`
* `advisory` `{_id, advisoryKey, title, summary, published, modified, severity, cvss, exploitKnown, sources[]}`

  * Index: `{advisoryKey:1}` unique, `{modified:-1}`, `{severity:1}`, text index (title, summary)
* `alias` `{advisoryId, scheme, value}`

  * Index: `{scheme:1,value:1}`, `{advisoryId:1}`
* `affected` `{advisoryId, productKey, rangeKind, introduced?, fixed?, arch?, distro?, ecosystem?}`

  * Index: `{productKey:1}`, `{advisoryId:1}`, `{productKey:1, rangeKind:1}`
* `reference` `{advisoryId, url, kind, sourceTag}`

  * Index: `{advisoryId:1}`, `{kind:1}`
* `merge_event` `{advisoryKey, beforeHash, afterHash, mergedAt, inputs[]}`

  * Index: `{advisoryKey:1, mergedAt:-1}`
* `export_state` `{_id(exportKind), baseExportId?, baseDigest?, lastFullDigest?, lastDeltaDigest?, cursor, files[]}`
* `locks` `{_id(jobKey), holder, acquiredAt, heartbeatAt, leaseMs, ttlAt}` (TTL cleans dead locks)
* `jobs` `{_id, type, args, state, startedAt, heartbeatAt, endedAt, error}`

**GridFS buckets**: `fs.documents` for raw payloads.

---

## 7) Exporters

### 7.1 Deterministic JSON (vuln‑list style)

* Folder structure mirroring `/<scheme>/<first-two>/<rest>/…` with one JSON per advisory; deterministic ordering, stable timestamps, normalized whitespace.
* `manifest.json` lists all files with SHA‑256 and a top‑level **export digest**.

### 7.2 Trivy DB exporter

* Builds Bolt DB archives compatible with Trivy; supports **full** and **delta** modes.
* In delta, unchanged blobs are reused from the base; metadata captures:

  ```
  {
    "mode": "delta|full",
    "baseExportId": "...",
    "baseManifestDigest": "sha256:...",
    "changed": ["path1", "path2"],
    "removed": ["path3"]
  }
  ```
* Optional ORAS push (OCI layout) for registries.
* Offline kit bundles include Trivy DB + JSON tree + export manifest.

### 7.3 Hand‑off to Signer/Attestor (optional)

* On export completion, if `attest: true` is set in job args, Concelier **posts** the artifact metadata to **Signer**/**Attestor**; Concelier itself **does not** hold signing keys.
* Export record stores returned `{ uuid, index, url }` from **Rekor v2**.

---

## 8) REST APIs

All under `/api/v1/concelier`.

**Health & status**

```
GET  /healthz | /readyz
GET  /status                              → sources, last runs, export cursors
```

**Sources & jobs**

```
GET  /sources                              → list of configured sources
POST /sources/{name}/trigger               → { jobId }
POST /sources/{name}/pause | /resume       → toggle
GET  /jobs/{id}                            → job status
```

**Exports**

```
POST /exports/json   { full?:bool, force?:bool, attest?:bool } → { exportId, digest, rekor? }
POST /exports/trivy  { full?:bool, force?:bool, publish?:bool, attest?:bool } → { exportId, digest, rekor? }
GET  /exports/{id}   → export metadata (kind, digest, createdAt, rekor?)
```

**Search (operator debugging)**

```
GET  /advisories/{key}
GET  /advisories?scheme=CVE&value=CVE-2025-12345
GET  /affected?productKey=pkg:rpm/openssl&limit=100
```

**AuthN/Z:** Authority tokens (OpTok) with roles: `concelier.read`, `concelier.admin`, `concelier.export`.

---

## 9) Configuration (YAML)

```yaml
concelier:
  mongo: { uri: "mongodb://mongo/concelier" }
  s3:
    endpoint: "http://minio:9000"
    bucket: "stellaops-concelier"
  scheduler:
    windowSeconds: 30
    maxParallelSources: 4
  sources:
    - name: redhat
      kind: csaf
      baseUrl: https://access.redhat.com/security/data/csaf/v2/
      signature: { type: pgp, keys: [ "…redhat PGP…" ] }
      enabled: true
      windowDays: 7
    - name: suse
      kind: csaf
      baseUrl: https://ftp.suse.com/pub/projects/security/csaf/
      signature: { type: pgp, keys: [ "…suse PGP…" ] }
    - name: ubuntu
      kind: usn-json
      baseUrl: https://ubuntu.com/security/notices.json
      signature: { type: none }
    - name: osv
      kind: osv
      baseUrl: https://api.osv.dev/v1/
      signature: { type: none }
    - name: ghsa
      kind: ghsa
      baseUrl: https://api.github.com/graphql
      auth: { tokenRef: "env:GITHUB_TOKEN" }
  exporters:
    json:
      enabled: true
      output: s3://stellaops-concelier/json/
    trivy:
      enabled: true
      mode: full
      output: s3://stellaops-concelier/trivy/
      oras:
        enabled: false
        repo: ghcr.io/org/concelier
  precedence:
    vendorWinsOverDistro: true
    distroWinsOverOsv: true
  severity:
    policy: max    # or 'vendorPreferred' / 'distroPreferred'
```

---

## 10) Security & compliance

* **Outbound allowlist** per connector (domains, protocols); proxy support; TLS pinning where possible.
* **Signature verification** for raw docs (PGP/cosign/x509) with results stored in `document.metadata.sig`. Docs failing verification may still be ingested but flagged; **merge** can down‑weight or ignore them by config.
* **No secrets in logs**; auth material via `env:` or mounted files; HTTP redaction of `Authorization` headers.
* **Multi‑tenant**: per‑tenant DBs or prefixes; per‑tenant S3 prefixes; tenant‑scoped API tokens.
* **Determinism**: canonical JSON writer; export digests stable across runs given same inputs.

---

## 11) Performance targets & scale

* **Ingest**: ≥ 5k documents/min on 4 cores (CSAF/OpenVEX/JSON).
* **Normalize/map**: ≥ 50k `Affected` rows/min on 4 cores.
* **Merge**: ≤ 10 ms P95 per advisory at steady‑state updates.
* **Export**: 1M advisories JSON in ≤ 90 s (streamed, zstd), Trivy DB in ≤ 60 s on 8 cores.
* **Memory**: hard cap per job; chunked streaming writers; backpressure to avoid GC spikes.

**Scale pattern**: add Concelier replicas; Mongo scaling via indices and read/write concerns; GridFS only for oversized docs.

---

## 12) Observability

* **Metrics**

  * `concelier.fetch.docs_total{source}`
  * `concelier.fetch.bytes_total{source}`
  * `concelier.parse.failures_total{source}`
  * `concelier.map.affected_total{source}`
  * `concelier.merge.changed_total`
  * `concelier.export.bytes{kind}`
  * `concelier.export.duration_seconds{kind}`
* **Tracing** around fetch/parse/map/merge/export.
* **Logs**: structured with `source`, `uri`, `docDigest`, `advisoryKey`, `exportId`.

---

## 13) Testing matrix

* **Connectors:** fixture suites for each provider/format (happy path; malformed; signature fail).
* **Version semantics:** EVR vs dpkg vs semver edge cases (epoch bumps, tilde versions, pre‑releases).
* **Merge:** conflicting sources (vendor vs distro vs OSV); verify precedence & dual retention.
* **Export determinism:** byte‑for‑byte stable outputs across runs; digest equality.
* **Performance:** soak tests with 1M advisories; cap memory; verify backpressure.
* **API:** pagination, filters, RBAC, error envelopes (RFC 7807).
* **Offline kit:** bundle build & import correctness.

---

## 14) Failure modes & recovery

* **Source outages:** scheduler backs off with exponential delay; `source_state.backoffUntil`; alerts on staleness.
* **Schema drifts:** parse stage marks DTO invalid; job fails with clear diagnostics; connector version flags track supported schema ranges.
* **Partial exports:** exporters write to temp prefix; **manifest commit** is atomic; only then move to final prefix and update `export_state`.
* **Resume:** all stages idempotent; `source_state.cursor` supports window resume.

---

## 15) Operator runbook (quick)

* **Trigger all sources:** `POST /api/v1/concelier/sources/*/trigger`
* **Force full export JSON:** `POST /api/v1/concelier/exports/json { "full": true, "force": true }`
* **Force Trivy DB delta publish:** `POST /api/v1/concelier/exports/trivy { "full": false, "publish": true }`
* **Inspect advisory:** `GET /api/v1/concelier/advisories?scheme=CVE&value=CVE-2025-12345`
* **Pause noisy source:** `POST /api/v1/concelier/sources/osv/pause`

---

## 16) Rollout plan

1. **MVP**: Red Hat (CSAF), SUSE (CSAF), Ubuntu (USN JSON), OSV; JSON export.
2. **Add**: GHSA GraphQL, Debian (DSA HTML/JSON), Alpine secdb; Trivy DB export.
3. **Attestation hand‑off**: integrate with **Signer/Attestor** (optional).
4. **Scale & diagnostics**: provider dashboards, staleness alerts, export cache reuse.
5. **Offline kit**: end‑to‑end verified bundles for air‑gap.

