TA-REDTEAM-2026-005 Remediation Report

Summary

Status: Fixed Commit: ade6d6b Files changed: 8 (3 modified, 5 new)

Fixed Findings

ID	Severity	Status	Evidence
005-A	High	fixed	`verifyDownloadedCarBuffer()` enforces `actual_sha256 == expected_sha256` and `actual_size == expected_size` before any file write or manifest acceptance
005-B	Medium	fixed	Cache path validates via `verifyDownloadedCarBuffer()`; stale cache deleted with `fs.rmSync`; unique tmpdir via `mkdtempSync`; packaging uses `verifiedCarFiles` only
005-C	Medium	fixed	`backup-nft-cars.yml` has sender allowlist for `repository_dispatch` + actor allowlist for `workflow_dispatch`; unauthorized sender exits non-zero
005-D	Low/Medium	fixed	`MAX_CAR_BYTES` (500MB default) per-file cap; `MAX_TOTAL_BYTES` (10GB default) total cap; both expected and actual sizes checked

Implementation

Expected hash / size enforcement

helper: verifyDownloadedCarBuffer(txid, info, buf, source) — validates sha256 + size, returns verified manifest item
download path: calls verifyDownloadedCarBuffer before fs.writeFileSync
cached path: calls verifyDownloadedCarBuffer on cached buffer; deletes on mismatch and re-downloads
fail behavior: fail++, verified: false, failed items excluded from verifiedCarFiles

TMP/cache safety

tmp strategy: fs.mkdtempSync(path.join(os.tmpdir(), 'nft-cars-')) — unique per run; or explicit NFT_CARS_TMP_DIR cleaned on start
verifiedCarFiles packaging: only files that passed verification enter tar archives

Manifest

expected fields: expected_sha256, expected_size
actual fields: actual_sha256, actual_size
match fields: sha256_match, size_match, verified
aggregate checks: sha256_check, size_check, all_expected_sha256_matched, all_expected_size_matched, all_verified

repository_dispatch hardening

workflow: backup-nft-cars.yml
allowlist: thechurchofagi|github-actions[bot] for repository_dispatch; thechurchofagi for workflow_dispatch

Resource limits

per-file cap: MAX_CAR_BYTES (default 500MB, env-configurable)
total cap: MAX_TOTAL_BYTES (default 10GB, env-configurable)

Tests

python3 scripts/test_download_nft_cars_expected_integrity.py
python3 scripts/test_download_nft_cars_tmp_cache_safety.py
python3 scripts/test_download_nft_cars_manifest_expected_actual.py
python3 scripts/test_backup_nft_cars_dispatch_hardening.py
python3 scripts/test_download_nft_cars_size_limits.py

Results

DOWNLOAD_NFT_CARS_EXPECTED_INTEGRITY_OK
DOWNLOAD_NFT_CARS_TMP_CACHE_SAFETY_OK
DOWNLOAD_NFT_CARS_MANIFEST_EXPECTED_ACTUAL_OK
BACKUP_NFT_CARS_DISPATCH_HARDENING_OK
DOWNLOAD_NFT_CARS_SIZE_LIMITS_OK
DOWNLOAD_NFT_CARS_FAIL_CLOSED_OK
BACKUP_NFT_CARS_INPUT_SAFETY_OK
NODE_EXEC_NO_SHELL_INJECTION_OK
FULL_EVIDENCE_CHAIN_CLI_INJECTION_OK
ACTION_PINNING_OK
WORKFLOW_INPUT_SAFETY_OK
LARGE_ASSET_STORAGE_POLICY_OK
NO_FORBIDDEN_LARGE_PATHS_TRACKED_OK
RELEASE_ASSET_MANIFEST_OFFLINE_OK
node --check scripts/download-nft-cars.mjs — OK

Residual Risk

Size limits are env-configurable; operators should review defaults for their use case
workflow_dispatch actor allowlist is single-account; expand if more maintainers need access

Closure Recommendation

TA-REDTEAM-2026-005 can be closed. All four sub-findings (A/B/C/D) are addressed with code-level enforcement and test coverage integrated into CI.