thanhnvandClaude Opus 4.8
62004c8725
evidence-pack.sh {pack|verify-pack} assembles a per-run proof pack from REAL
on-disk logs (summaries only — no raw secret/PII copied; decision-log passes the
data-exfil guard or the pack aborts). Produces the standard set: run-summary,
h1..h7 reports, redteam-result, benign-fp-report, artifact-manifest, decision-log,
plus a signed manifest head (evidence-pack.sig).
Tamper-evident: verify-pack recomputes every file hash vs artifact-manifest.json
(any change fails) and verifies the RSA signature over manifest-head.txt (a
manifest re-forge fails without the off-repo key).
Certified run: run-summary.certified is true ONLY when required gates pass
(H4 exercised, H5 audit chain valid, H5 telemetry verified, no unresolved cost
spike, benign-FP within budget) and none was silently skipped — missing evidence
records an honest reason and does NOT certify.
CLI mapping: `casan pack <id>` -> evidence-pack.sh pack; `casan verify-pack <id>`
-> evidence-pack.sh verify-pack. phase3-evidence-pack-tests.sh covers it.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
74 lines
2.5 KiB
Python
Executable File
74 lines
2.5 KiB
Python
Executable File
#!/usr/bin/env python3
|
|
"""CASAN Plan-09 — Evidence Pack verifier (MVP).
|
|
|
|
Recomputes the hash of every file in a pack and compares it to the stored
|
|
artifact-manifest.json. Any change to any packed file flips a hash and fails
|
|
verification. (The bash wrapper additionally verifies the RSA signature over
|
|
manifest-head.txt, which stops an attacker who rewrites the manifest too.)
|
|
|
|
Argv: <pack_dir>
|
|
Exit: 0 intact, 1 tamper detected / manifest missing.
|
|
"""
|
|
import hashlib
|
|
import json
|
|
import os
|
|
import sys
|
|
|
|
|
|
def main():
|
|
pack_dir = sys.argv[1]
|
|
manifest_path = os.path.join(pack_dir, "artifact-manifest.json")
|
|
if not os.path.isfile(manifest_path):
|
|
sys.stderr.write("EVIDENCE_PACK_NO_MANIFEST\n")
|
|
return 1
|
|
try:
|
|
manifest = json.load(open(manifest_path, encoding="utf-8"))
|
|
except ValueError:
|
|
sys.stderr.write("EVIDENCE_PACK_MANIFEST_CORRUPT\n")
|
|
return 1
|
|
|
|
stored = manifest.get("files", {})
|
|
mismatches = []
|
|
|
|
# Every file recorded in the manifest must still hash to the same value.
|
|
for fn, want in stored.items():
|
|
path = os.path.join(pack_dir, fn)
|
|
if not os.path.isfile(path):
|
|
mismatches.append(f"{fn}:missing")
|
|
continue
|
|
with open(path, "rb") as f:
|
|
got = hashlib.sha256(f.read()).hexdigest()
|
|
if got != want:
|
|
mismatches.append(f"{fn}:hash_changed")
|
|
|
|
# A new unmanifested file (except sig/head) is also tampering.
|
|
for fn in os.listdir(pack_dir):
|
|
if fn in ("artifact-manifest.json", "evidence-pack.sig", "manifest-head.txt"):
|
|
continue
|
|
if os.path.isfile(os.path.join(pack_dir, fn)) and fn not in stored:
|
|
mismatches.append(f"{fn}:unexpected_file")
|
|
|
|
# The stored manifest_head must match the recomputed head of `stored`.
|
|
canonical = json.dumps(stored, sort_keys=True, separators=(",", ":"))
|
|
head_now = hashlib.sha256(canonical.encode()).hexdigest()
|
|
if head_now != manifest.get("manifest_head"):
|
|
mismatches.append("manifest_head:mismatch")
|
|
|
|
if mismatches:
|
|
sys.stderr.write("EVIDENCE_PACK_TAMPERED " + " ".join(mismatches) + "\n")
|
|
return 1
|
|
|
|
cert = "unknown"
|
|
rs = os.path.join(pack_dir, "run-summary.json")
|
|
if os.path.isfile(rs):
|
|
try:
|
|
cert = str(json.load(open(rs, encoding="utf-8")).get("certified"))
|
|
except ValueError:
|
|
pass
|
|
print(f"EVIDENCE_PACK_INTACT files={len(stored)} certified={cert} head={head_now}")
|
|
return 0
|
|
|
|
|
|
if __name__ == "__main__":
|
|
sys.exit(main())
|