aicr-managing-openvex

Managing .openvex.json

.openvex.json carries per-CVE reachability evidence used to suppress vulnerability findings in the aiperf-bench container image. The file is consumed by the Weekly Image Vulnerability Scan workflow (.github/workflows/vuln-scan-images.yaml) via the vex: input on anchore/scan-action@v7.4.0, which passes it to grype as --vex .openvex.json.

It is also the source for the OpenVEX attestation each release publishes on every platform manifest. .github/actions/sbom-and-attest validates this file, then runs tools/openvex-bind to rewrite each statement's bare pkg:oci/<image> products to pkg:oci/<image>@sha256:<platform-digest> and signs that projection. Edit this file only: the published document is generated, never committed. Three consequences for edits here: a statement whose product PURL does not name a released image is silently dropped from every projection; statuses, justifications and impact statements are published verbatim to a public registry, signed, on every released image; and document-level tooling is not published at all, because the projection replaces it with an identifier of the generator (invariant 5).

This skill exists because the file has non-obvious invariants — most notably the product-PURL matching rule — and getting them wrong silently no-ops every statement in the document.

When to use

• A Weekly Image Vulnerability Scan run reports HIGH+ CVE(s) on the aiperf-bench image and a maintainer needs to add a suppression after verifying reachability.
• A maintainer bumps the aiperf pin (AIPERF_VERSION in validators/performance/aiperf-bench.Dockerfile) or its dependency pins, fixing a CVE that was previously suppressed → the entry must be removed.
• A maintainer audits the file before a release to drop stale entries.
• The scan workflow shows non-zero HIGH+ counts but VEX is "supposed to cover them" — typically a PURL or vulnerability-ID mismatch.

Non-negotiable invariants

These are the rules that, when violated, cause silent suppression failures. Verify each one before claiming a statement is correctly applied.

1. products[].purl must equal the grype image PURL

Grype derives the OCI image PURL from the registry repository basename, not from org.opencontainers.image.title. For the aiperf-bench image:

• CI scans ghcr.io/nvidia/aicr-validators/aiperf-bench:<tag> → grype PURL pkg:oci/aiperf-bench.
• A local build tagged aicr-aiperf-bench:test (matching the title label) → grype PURL pkg:oci/aicr-aiperf-bench.

Every statement in this repo therefore carries both product entries:

"products": [
  { "@id": "pkg:oci/aicr-aiperf-bench", "identifiers": { "purl": "pkg:oci/aicr-aiperf-bench" } },
  { 

If you add a statement, include both. If you rename the image or add a new image to the VEX scope, derive the new PURL by repeating the local reproduction below and checking .source.target.userInput against the generated PURL — do not guess from labels.

2. vulnerability.name must equal grype's primary ID

Grype emits a single primary ID per match (the .vulnerability.id field of .matches[]). For ecosystem advisories with both a GHSA and a CVE, the primary ID is usually the GHSA; the CVE shows up only as a relatedVulnerabilities[].id alias. OpenVEX matching is by exact name — a CVE in the VEX file will not match a GHSA primary ID even though they describe the same advisory.

Use the ID that appears in the HIGH+: line of the scan artifact / Slack notification (which prints <pkg> <primary-id> (<aliases>)), or extract it directly from the JSON:

3. Justifications must use the OpenVEX v0.2.0 enum

Allowed values for not_affected status:

• component_not_present — package isn't in the image at all.
• vulnerable_code_not_present — package is in the image but the specific vulnerable symbol/file/build is absent (e.g., conditionally compiled out, removed in the shipped version).
• vulnerable_code_not_in_execute_path — code exists but the workload never invokes it.
• vulnerable_code_cannot_be_controlled_by_adversary — code is reachable but inputs are not attacker-influenced.
• inline_mitigations_already_exist — runtime hardening (seccomp, caps drop, etc.) blocks the trigger.

vulnerable_code_not_in_execute_path is the most common choice for this image; vulnerable_code_not_present is used when the symbol is conditionally compiled out (e.g., Windows-only APIs in a Linux glibc).

4. impact_statement must cite concrete evidence

Every statement requires a substantive impact_statement — not a hand-wave. Reviewers and downstream consumers (auditors, customers reading SBOMs) read this. Cite at least one of:

• Specific grep against aiperf source that returns zero hits, with the pattern shown (e.g., grep -rn -E '^(import|from) (gzip|lzma|bz2)').
• Specific file path in the image / aiperf source that proves a feature is gated off (e.g., aiperf/plot/dashboard/server.py is only reached via the aiperf plot subcommand).
• Specific Dockerfile clauses that establish the hardening claim (USER, capabilities, base-image choice).
• Upstream advisory text that limits the trigger to a config we don't use.

See existing statements for the expected density; CI does not enforce this but reviewers will.

5. Document-level fields are short metadata, not prose

OpenVEX v0.2.0 defines exactly nine document-level fields: @context, @id, author, role, timestamp, last_updated, version, tooling and statements. Each is short, structured metadata -- an IRI, an author or role string, an RFC 3339 timestamp, an integer, a generator identifier -- and statements is the only one that carries substance. None of them is a free-form prose field, and there is no notes or changelog field.

So anything not scoped to a single CVE has no home in the document at all: what a revision changed and how it was verified goes in that revision's PR description, and work that is not finished yet goes in vex-state.yaml (see Carried state below).

tooling is where this went wrong. Each revision appended its own rationale to it because it was the only free-form string available, and it reached 8,010 bytes. Since v0.21.0 every release signs it onto all seven images, six of which project to zero statements, so the field was publishing one image's dependency triage as a claim about the others (NVIDIA/aicr#2706). Two mechanisms now stop a repeat, and both are load-bearing rather than advisory:

• tools/openvex-bind replaces tooling with a fixed identifier of itself in every projection, so a committed value cannot be published.
• .github/actions/sbom-and-attest/openvex-guard.sh rejects any document-level string over 256 bytes, in both source and projection mode. A tooling that regrows fails the release, and TestReleaseOpenVEXValidation in tests/releasepolicy fails the PR first.

Per-statement version and last_updated are deliberately unused too. version numbers a statement's own revisions, not the document revision it was introduced at, so either reading is a field no consumer reads and the next editor has to remember. last_updated would always equal the document timestamp, because the stale audit below re-verifies every statement on every edit.

Where rationale goes

The PR description is the record of a revision, not a copy of one: it is reviewable, linkable, carries the scan-run references, and needs no maintenance afterwards. Do not restate it in the document, and do not open a changelog file for it.

vex-state.yaml is the opposite thing, and the distinction is what keeps both small. It holds unfinished work, not history, and every entry states what would invalidate it so it can be deleted when that happens. The next section is its contract.

Carried state (vex-state.yaml)

Some of this work does not finish inside one session. A statement's real confirmation is a CI run that has not happened yet; a bump you checked and found unavailable will be worth re-checking only when upstream moves; a decision not to suppress something is invisible to whoever reads the document next. None of that fits in a VEX statement, and writing it into the document is what grew tooling to 8,010 bytes.

.agents/skills/aicr-managing-openvex/vex-state.yaml carries it instead. Read it first, update it last, on every invocation:

1. At the start, work through deferred_verifications. For each, run the check it names. If it passes, delete the entry and say so in the PR description. If it fails, that failure is the finding you are now triaging, ahead of whatever brought you here.
2. Before triaging a new finding, check known_negatives. If the bump you are about to evaluate is already recorded as unavailable and nothing named in invalidated_by has happened, do not re-derive it.
3. Before deleting or adding a statement, check deliberate_exclusions. A finding that is deliberately unsuppressed must stay unsuppressed until its invalidated_by condition fires.
4. At the end, add entries for anything you could not finish: a check that needs a later run, a negative you would hate to redo, a decision not to act. Every entry names what would invalidate it. If you cannot name that, the note belongs in the PR description instead.

The lifecycle is the whole point. Entries are deleted when they resolve, not rewritten as history: a file that only ever grows is the failure this replaced. Evidence caveats ride on the entry they qualify. A deletion validated against a scan of the new base rather than against rebuilt bytes is a weaker claim than it looks, so it is recorded on the deferred verification that will settle it, and both go when the scan confirms.

Local reproduction (canonical)

The only way to be certain a statement applies is to run the same grype invocation CI runs and confirm the finding moves from .matches[] to .ignoredMatches[]. The recipe:

A new statement is correct only when step 4 returns [] for the vulnerability it targets and step 5 lists it under appliedIgnoreRules with namespace = "vex".

Shortcut: scan CI's exact images instead of building

The scan workflow builds and pushes every image with tag scan-<full-head-sha> before scanning. Those tags stay on GHCR, so you can scan the exact bytes CI scanned — all seven matrix images, not just aiperf-bench — without a local docker build:

Use this for triage and the stale audit (it covers aicr-gate and aicr, which have no local Dockerfile build path). Use the docker-build recipe above only when validating a Dockerfile change before it is pushed. Caveat: a local grype DB newer than this morning's CI run can surface advisories CI hasn't seen yet — treat those as incoming findings, not discrepancies.

Triage a new finding from the scan workflow

The weekly scan (Thursdays, 06:00 UTC) emits HIGH+ identifiers in the per-image artifact and Slack notification:

Before the per-ID work, clear vex-state.yaml: resolve any outstanding deferred_verifications and re-read the known_negatives and deliberate_exclusions that bear on this image.

For each ID:

1. Check upstream first. Read the GHSA / NVD page. If a fix has shipped in a version reachable from aiperf's pins, the right action is usually not a VEX entry — it's bumping the aiperf pin so the fix lands and the finding disappears. Bump AIPERF_VERSION in validators/performance/aiperf-bench.Dockerfile, verify with the local repro above, and skip the rest of this section.
2. If a bump isn't feasible, prove non-reachability. The work that must be visible in impact_statement:
   • Identify the vulnerable function / file in upstream source.
   • Check whether aiperf imports it (grep -rn patterns).
   • Check whether the workload (aiperf profile <text-llm> invoked by validators/performance/inference_perf_constraint.go) reaches the code path even transitively.
   • Note any base-image constraint (e.g., python:3.13-slim is Debian trixie / glibc / Linux only, so Windows-only and glibc-only-on-certain-locales conditions are inert).
3. Author the statement with both PURLs (see invariant 1), the correct primary ID (see invariant 2), a v0.2.0 justification (see invariant 3), and concrete evidence (see invariant 4).
4. Reproduce locally, confirm step-4 returns [] for the new ID.
5. Run the stale audit (next section) — every edit to the file MUST include it, so dead statements never accumulate alongside new ones.
6. Commit and dispatch the workflow to confirm CI matches local. Run gh workflow run "Weekly Image Vulnerability Scan" --repo NVIDIA/aicr --ref main, watch with gh run watch <id> --exit-status, inspect the aiperf-bench scan-result artifact.
7. Record what you could not confirm. Some checks are only possible after merge: the scan that runs against the rebuilt image, or the attestation the next release publishes. Do not assert them in prose anywhere; add a deferred_verifications entry to vex-state.yaml naming the check and how to run it, so the next invocation resolves and deletes it.

Stale audit (MANDATORY on every edit)

Statements rot: dependencies get upgraded past fixes, advisories get withdrawn, components leave the image. A stale statement is invisible — it applies to nothing, silently — so the audit runs on every change to the file, not just before releases. (The audit that introduced this rule found 12 dead statements out of 70.)

Scan every image the document has product entries for (currently aiperf-bench alone; the aicr-gate and aicr statements were retired at revisions 12 and earlier) using the scan-<sha> shortcut above, then diff declared statements against applied rules:

For each candidate, classify before deleting — three distinct cases:

1. Gone entirely (grep <id> /tmp/scan-<image>.json → 0 hits, including aliases): the finding no longer exists (package upgraded past the fix, advisory withdrawn). Delete.
2. Present but ignored by fix-state: wont-fix (appears in .ignoredMatches[] with appliedIgnoreRules[].namespace == ""): --only-fixed already hides it, so the VEX statement never applies. Delete — do not keep it "just in case": if the distro ships a fix, the weekly image rebuild absorbs it automatically, and until it does the finding must surface rather than be pre-suppressed (a fix that becomes reachable means bump, not VEX).
3. Present in .matches[] under a different primary ID (a CVE statement while grype emits the GHSA, or vice versa): NOT stale — a name mismatch. Fix vulnerability.name per invariant 2.

After deleting, re-run the scans for all covered images and confirm the vex-suppressed counts still match the latest CI run for the statements that remain (deleting must be count-neutral).

The workflow counts suppressed rows, not statements: a statement whose CVE matches two packages counts twice. Revision 14's 18 statements produced 25 rows (7 openssl CVEs on both libssl3t64 and openssl-provider-fips, plus 11 single-row pillow/aiohttp GHSAs); revision 15's 11 statements produce 11. Predict the row count before reading the scan, or a correct run looks like a discrepancy.

Bump the document version and refresh timestamp in the same edit, and write what changed, what it retired, and how you verified it into the PR description (invariant 5). That is the record: nothing about the revision goes into the document itself.

Anti-patterns

• Using pkg:oci/<image-title> when CI scans pkg:oci/<repo-basename>. The label has no effect on grype's image PURL. Always include the registry-basename form.
• Using a CVE ID in vulnerability.name when grype emits a GHSA primary. The two names are NOT interchangeable for OpenVEX matching.
• Suppressing a CVE the dependency upgrade would have fixed. VEX is for findings that cannot be remediated by upgrading; if the fixed version is reachable, bump the pin instead.
• Boilerplate impact_statement ("not exploitable", "low risk"). Cite the specific code path, file, or upstream language that supports the claim. Reviewers will reject thin justifications.
• Forgetting to refresh timestamp and version at the document level when materially changing statements. Bump version on each substantive edit and update timestamp (or Reviewed: notes) so downstream consumers can detect drift.
• Adding a statement without local reproduction. A statement that fails to apply is invisible — there is no warning, no failure, no log line. The only signal is that the CVE keeps appearing in scans. Always run the local repro before committing.
• Appending this revision's narrative to tooling, or to any other document-level field. tooling names what generated the document; it is not a changelog. Appending to it is how it reached 8,010 bytes of prose that every release signs onto every image. Per-CVE reasoning goes in the statement, unfinished work in vex-state.yaml, and everything else in the PR description. The guard now rejects the attempt, but the point is that there was always a better place for it.
• Dropping an evidence caveat because the statement it qualified is being deleted. "Validated against the base image, not a rebuild" is a limitation on the claim. Record it on the vex-state.yaml entry for the scan that will settle it, and in the PR description that performs the deletion.
• Leaving a resolved entry in vex-state.yaml "for the record". A confirmed verification is finished; the record is the PR that confirmed it. Entries that are never removed are exactly how tooling grew.

Quick reference

• Workflow: .github/workflows/vuln-scan-images.yaml
• VEX document: .openvex.json
• Carried state (deferred checks, known negatives, exclusions): .agents/skills/aicr-managing-openvex/vex-state.yaml
• Release publication: .github/actions/sbom-and-attest/action.yml + tools/openvex-bind (digest binding, tooling normalization) + .github/actions/sbom-and-attest/openvex-guard.sh (contract and size bound)
• Grype config (excludes for source scans only): .grype.yaml
• Image source: validators/performance/aiperf-bench.Dockerfile
• aiperf pin: AIPERF_VERSION ARG in that Dockerfile
• Grype version pin (read from scan-action): GrypeVersion.js at the pinned scan-action SHA in the workflow
• Workflow output format (per image, in scan-N artifact):

  <short-name>: N critical, N high, N medium, N low, N negligible (N VEX-suppressed)
    HIGH+: <pkg> <primary-id> (<aliases>), ...