git.stella-ops.org/docs/modules/attestor/repro-bundle-profile.md

Repro Bundle Profile (SLSA v1 + in-toto + DSSE)

Status

• Planned contract (gap-closure track).
• Implementation sprint: docs/implplan/SPRINT_20260209_001_DOCS_repro_bundle_gap_closure.md.

Purpose

• Define the minimum reproducibility evidence required for release promotion.
• Standardize canonicalization rules so rebuild and verification outcomes are deterministic.
• Preserve online and offline parity for transparency verification workflows.

Required bundle contents (per artifact)

1. build_provenance.json with SLSA v1 predicate fields:
   • builder.id and builder.version
   • source binding (invocation and commit)
   • materials[] with pinned digests
   • canonicalized build command representation
   • pinned toolchain digest (@sha256:...)
2. in_toto.link mapping materials to products with deterministic digests.
3. DSSE signatures/envelopes for provenance and link payloads.
4. Transparency evidence:
   • Online mode: Rekor entry metadata.
   • Offline mode: local checkpoint/tile bundle and verification metadata, including Rekor leaf hash (leafHash), path hashes, and checkpoint root.

Canonicalization policy (fail-closed)

• Paths and filenames must be Unicode NFC.
• JSON payloads must be canonicalized with sorted keys and deterministic encoding.
• PURLs/material references must be pinned, digest-backed, and deterministically ordered.
• Archive outputs must use deterministic metadata/order:
  • fixed timestamps (policy default: zero epoch)
  • stable uid/gid and owner names
  • fixed mode policy
• Line endings must be normalized (policy default: LF).
• Build environments must pin deterministic settings:
  • LC_ALL=C
  • TZ=UTC
  • stable source date epoch
• Toolchains must be digest-pinned; mutable tags are non-compliant in strict mode.

Verification modes

Online mode

• Verify DSSE signatures.
• Verify SLSA/in-toto policy compliance.
• Verify Rekor inclusion against trusted log/checkpoint state.

Offline mode

• Verify DSSE signatures with bundled trust roots/keys.
• Verify bundled inclusion proof data cryptographically (leaf hash + Merkle path + checkpoint root) without network.
• Missing/invalid proof material is fail-closed by default.
• If break-glass verification is allowed, it must be explicitly configured and recorded in evidence with machine-readable marker(s).

Promotion gate contract

• Promotion must block when any required repro evidence is missing or invalid.
• Promotion must block when canonicalization policy fails.
• Promotion must block when toolchain digest pinning is absent.
• Gate output must include stable rejection codes and references to failed evidence files for replay.

Component ownership map

• Attestor: strict predicate validation, DSSE handling, Rekor verification (online/offline).
• ReleaseOrchestrator: fail-closed promotion gate enforcement and policy simulation.
• EvidenceLocker: storage/export contracts for repro-bundle artifacts and offline verification packs.
• Provenance: provenance model extensions and deterministic serialization support.
• devops: deterministic build/container/pipeline defaults and toolchain pinning.

Test expectations

• Deterministic fixtures for valid and invalid bundles.
• Unit + integration coverage for canonicalization policy and strict validation.
• End-to-end coverage for online and offline promotion checks.
• Negative tests for each fail-closed rule.