mirror of
https://github.com/shankar0123/certctl.git
synced 2026-06-07 18:11:32 +00:00
shankar0123
43836aca7c
Sprint 6 closure of the audit's HIGH-severity COMP-001-HASH finding.
Pre-fix posture: migration 000018 installs a WORM trigger on
audit_events that blocks UPDATE / DELETE for the application role.
But the trigger header itself documents a compliance-superuser
bypass (backup restore, retention purges, breach recovery). Without
a hash chain, that role can rewrite any row's actor / action /
details / timestamp / event_category with no on-disk trace.
HIPAA §164.312(b), FedRAMP AU-9, NIST 800-53 AU-10 want tamper-
EVIDENCE, not just tamper-prevention. This commit ships the
evidence layer.
Wire shape:
migrations/000047_audit_events_hash_chain.up.sql
+ pgcrypto extension (digest function)
+ audit_chain_head: single-row sentinel table holding the most
recent row_hash; FOR UPDATE row-lock serialises chain writes
under concurrent INSERTs so two parallel writers can't read
the same prev_hash and produce a forked chain
+ audit_events: prev_hash + row_hash columns
+ audit_events_canonical_payload(): centralised hash input
builder. UTC + microsecond ISO-8601 keeps the hash session-
timezone-independent. All columns separated by '|' so a
concatenation-ambiguity exploit can't fabricate a collision
+ audit_events_compute_hash_chain(): BEFORE-INSERT trigger
function. Reads sentinel FOR UPDATE → computes
sha256(prev_hash || id || actor || actor_type || action ||
resource_type || resource_id || details::text ||
timestamp_utc_iso || event_category) → writes both columns +
advances the sentinel
+ backfill loop walks every existing row in (timestamp ASC, id
ASC) order; WORM trigger temporarily DISABLEd inside this
migration's transaction so backfill UPDATEs land cleanly,
ENABLEd before COMMIT
+ audit_events_verify_chain(): STABLE plpgsql verifier. Walks
the chain end-to-end and returns the first break:
(first_break_id TEXT, first_break_pos INT, row_count INT)
internal/repository/postgres/audit.go
+ AuditRepository.VerifyHashChain — calls the SQL function and
maps the OUT parameters to Go return values
internal/repository/interfaces.go
+ AuditRepository.VerifyHashChain in the contract; every
in-memory mock + stub picks up the no-op implementation
internal/scheduler/scheduler.go
+ AuditChainVerifier + AuditChainBreakRecorder interfaces
+ auditChainVerifyInterval (default 6h)
+ auditChainVerifyLoop: runs once on start + every tick;
atomic.Bool guard + 5-min per-tick context timeout match every
other GC loop's pattern
internal/service/audit_chain_metric.go
+ AuditChainCounter type with atomic counters. Sticky-first-
detection on (BrokenAtID, BrokenAtPos) so the actionable
alarm doesn't drift across walks. Snapshot() returns the
full state for the metrics handler
internal/api/handler/metrics.go
+ AuditChainCounterSnapshotter interface + Prometheus
exposition for four series:
certctl_audit_chain_break_detected_total counter (the alarm)
certctl_audit_chain_verify_total counter (walks done)
certctl_audit_chain_rows gauge (last walk size)
certctl_audit_chain_last_verified_at gauge (unix seconds)
internal/config/config.go
+ AuditChainConfig{ VerifyInterval } + CERTCTL_AUDIT_CHAIN_VERIFY_INTERVAL
cmd/server/main.go
+ wires AuditChainCounter into both the scheduler (recorder) +
metrics handler (snapshotter) — single instance shared so the
writer + reader are guaranteed to converge
internal/repository/postgres/audit_chain_test.go (NEW)
+ TestAuditEventsHashChain_FreshTable: empty walk → clean
+ TestAuditEventsHashChain_AppendLinksRows: three INSERTs
produce a strictly-linked chain; prev_hash on row 0 is NULL;
verifier walks clean over the 3 rows
+ TestAuditEventsHashChain_VerifierDetectsTampering: simulate
the compliance-superuser threat model (DISABLE WORM, UPDATE
a middle row, ENABLE WORM); verifier returns the tampered
row's id at position 1
docs/operator/audit-chain.md (NEW)
+ Layered-defenses explainer (WORM + hash chain). Verifier
function reference. Recommended Prometheus alert rule.
Performance scaling table (10k to 10M rows). Step-by-step
runbook for what to do when a break is detected. Operator
configuration table.
Test-stub additions for AuditRepository.VerifyHashChain:
internal/service/testutil_test.go — mockAuditRepo
internal/service/acme_test.go — fakeAuditRepo
internal/integration/lifecycle_test.go — mockAuditRepository
internal/api/handler/scep_intune_e2e_test.go — intuneE2EAuditRepo
Verified locally:
go vet ./... (clean)
gofmt -l internal/ cmd/ (clean)
go test -short -count=1 ./internal/scheduler/... ./internal/config/...
./internal/service/... ./internal/api/handler/... ./internal/repository/...
(all green)
Verified with testcontainers + postgres:16-alpine + the migration
runner (not gated under -short — requires docker):
go test -count=1 -run TestAuditEventsHashChain ./internal/repository/postgres/...
Closes COMP-001-HASH leg of Sprint 6. COMP-002-RETENTION lands in
the next commit (separate concern: federated-user PII retention).