Content-pattern scanning

Available since v1.3.0.

Push-level check applied against both the aggregate diff and every pushed commit’s message. Flags structured identifier content (national ID numbers, IBANs, credit card numbers, crypto wallet addresses, etc.) using fogwall’s built-in pattern bundles — distinct from secret scanning, which targets credential-shaped content (API keys, tokens). Every bundle here requires a structural checksum or Presidio-derived regex match, not free-text PII detection (names, addresses, emails) — that class needs NLP/NER to keep an acceptable false-positive rate, which is out of scope; see Design notes below.

WARN-only on the push path — a match is recorded as a WARN step for the reviewer to see, it never blocks the push. These patterns have a real false-positive rate (a bare regex match on a short numeric identifier can’t be fully disambiguated from unrelated numbers), and there’s currently no override path for a wrongly-blocked push. Since every push already requires a human reviewer to look at it, WARN gets the finding in front of them without the downside of blocking on a false positive.

Blocking on the SCM API path — that reasoning depends on the reviewer, and an SCM API entity has none: it is forwarded to the upstream or refused, with no held state to annotate. A warning recorded against a merge request description that is already published is not a control, so a match there refuses the request (REJECTED) the same way a blocked term or a detected secret does. See Content inspection.

Bundle content (regexes, context keywords, structural validators like Luhn/IBAN/Base58Check checksums) is hand-ported from data-privacy-stack/presidio (MIT licensed) where noted below — see PROVENANCE.md alongside the bundle resources in the fogwall source tree for exact provenance, including the small number of validators (US bank routing, Bitcoin SegWit/Taproot, Ethereum) that aren’t from Presidio. fogwall does not run Presidio itself; only the matching logic is translated to Java.

content-patterns:
  enabled: true
  bundles:
    - national-id-all-geos # every national-id-<cc> bundle below
    - generic-iban
    - generic-crypto-wallet
    # generic-credit-card and generic-us-bank-routing use a Luhn-strength (mod-10) checksum - noisier than the
    # above, so they're opt-in only; add them individually, or use the generic-all alias for all four generic
    # bundles at once.
  scan-diff: true # set false to skip scanning the push diff
  scan-commit-messages: true # set false to skip scanning commit messages
  scan-scm-api: true # set false to skip scanning SCM API titles, descriptions and comments

scan-diff/scan-commit-messages/scan-scm-api independently gate the three content sources - all default true, so selecting a bundle covers every surface it can appear on. An operator who considers commit messages low-risk (or wants to reduce push-summary noise) can disable that half without affecting diff scanning, and vice versa. This is distinct from disabling a bundle: the bundle selection still applies to whichever source(s) remain enabled.

Available bundles

Two tiers: national-id-<cc> bundles (ISO 3166-1 alpha-2 country codes) each cover a single country’s national-identity-registry number — not that country’s full PII catalog. generic-<type> bundles cover a data type that isn’t tied to a jurisdiction. Two group aliases are always available: national-id-all-geos (every national-id-* bundle) and generic-all (every generic-* bundle).

National ID bundles

Generic bundles

Design notes

Presidio’s recognizer catalog goes well beyond what fogwall ports: unstructured categories like names, physical addresses, phone numbers, and email addresses rely on Presidio’s NLP/NER pipeline to keep an acceptable false-positive rate, not a checksum. fogwall has no NLP pipeline (that’s the dependency this feature deliberately avoided — see PROVENANCE.md), so only checksum-or-strict-structural-regex data types are in scope. If a data type doesn’t have a real checksum, it isn’t a good fit for this WARN-only, regex-based mechanism.