v0.3.0 made the untrusted upload path unusable: measured on both doors, an
ordinary remote image fail_secure'd and an ordinary link/autolink/refdef
quarantined, so only documents without external references persisted.
Two independent defects compounded; neither fix works alone:
1. `markdown-image: HIGH` fired on any external image. The exfil primitive is a
URL that moves bytes outward, not an image. `is_ordinary_url` now grades on
shape - http(s)/protocol-relative, no query, no userinfo, no percent-escape,
no opaque host label or path segment -> LOW; anything data-carrying keeps the
carrier's severity. raw-html and data: URIs stay HIGH unconditionally.
Opacity reuses entropy's primitives; floors calibrated against real doc URLs
(worst legit token H=4.08, exfil segments 4.36-4.54) and frozen in
calibration.
2. The quarantine_default floor fired on ANY finding, a premise that broke when
every ordinary link became a finding. It now fires at MEDIUM+ - a no-op for
every detector that shipped before 0.3.0 (no LOW/INFO exists), which is what
makes this a patch rather than a minor.
The corpus blind spot that let this pass 522 green tests is closed: the FP
corpus carries realistic markdown and is asserted on the OUTPUT gate under
PRESET_USER_UPLOAD, with a counter-corpus of exfil-shaped URLs that must still
block. Beaconing and short opaque segments are conceded in LIMITATIONS and
asserted by the coverage matrix rather than papered over.
No new public API; no new preset (0.4.0 work); allow_reserved default unchanged.
Module 11's final deliverable (BRIEF §9, PLAN §132), built last. Exercises the
full public toolkit as a consumer would compose it — the _ingest helper doubles
as the README worked example.
- test_showcase: ONE poisoned artifact planting a vulnerability per detection
channel — 5 invisible carriers (zero-width/BIDI/unicode-tag/html-comment/
data-uri), injection across raw + homoglyph + rot13 + whole-string-base64
(decode-and-rescan) channels with DISTINCT lexicon ids so dedup won't merge
them, plus a credential the mock transform leaks into its output (LLM02). All
10 planted labels caught; disposition FAIL_SECURE; egress evidence never
carries the secret value; a clean document + clean transform WARNs (no FP).
- test_corpus: adversarial recall == 100% over the planted classes (a silent
drop is a regression), and a false-positive corpus of attack-resembling legit
content (injection vocabulary, secret-shaped placeholders/varrefs, high-entropy
checksums) that disposes WARN under a trusted source — most producing NO
finding (the suppression rules hold). One MEDIUM homoglyph case proves hard-fail
is an explicit opt-in: same finding WARNs trusted, QUARANTINEs under upload.
Secret fixtures assembled from fragments (gitleaks-safe); every payload verified
against the real detectors before assertion. 12 new tests; 201 green total.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HyRCQMocjZ6SmSQ6JidJ2k
