CI on commit 7e22204 (Phase 3 challenges) failed three lint checks under
golangci-lint. Two were contextcheck on internal/service/acme.go
RespondToChallenge, where the validator-pool dispatch deliberately
detached from the request ctx via 'context.Background()' so the async
WithinTx survives the HTTP handler returning. contextcheck rightly
flagged the non-inherited context — the canonical Go 1.21+ answer for
this exact pattern is context.WithoutCancel(ctx), which preserves
inherited values (logger, trace IDs, audit actor) but detaches
cancellation. Swapping that in clears both contextcheck hits.
The third was ST1021 on internal/api/acme/validators.go: a comment
intended for the (*Pool).Snapshot() method had landed above the
PoolSnapshot type by accident. Split the comment — one prose line
for the type, one for the method — so each exported symbol carries
its own properly-anchored doc.
Confirmed local 'go vet' clean and 'go test -short -count=1' green
across internal/service/ and internal/api/acme/ before commit.
Wires up the actual challenge-validation machinery so profiles in
acme_auth_mode='challenge' resolve end-to-end. After this commit,
cert-manager 1.15+ with `solver: http01: ingress` against a
challenge-mode profile completes a real HTTP-01 flow and gets a cert.
DNS-01 + TLS-ALPN-01 share the same code path with the appropriate
validator selection.
Architecture (the load-bearing parts):
- 3 separate semaphore-bounded worker pools (one per challenge type),
so HTTP-01 and DNS-01 can't starve each other under load. Default
weight 10 per type; tunable via CERTCTL_ACME_SERVER_HTTP01_CONCURRENCY,
DNS01_CONCURRENCY, TLSALPN01_CONCURRENCY.
- 30s per-challenge timeout (configurable via PoolConfig.PerChallengeTimeout).
- HTTP-01 validator runs validation.IsReservedIPForDial (newly
exported wrapper preserving the existing private impl byte-for-byte
for the network scanner + ValidateSafeURL paths) on the resolved
IP — both at the initial dial and every redirect hop. SSRF probes
into private IP space are refused before the connect.
- DNS-01 validator uses a dedicated resolver pointed at
CERTCTL_ACME_SERVER_DNS01_RESOLVER (default 8.8.8.8:53) — does
NOT use the system resolver to keep behavior deterministic across
deployments. Wildcard handling: `*.example.com` queries
_acme-challenge.example.com.
- TLS-ALPN-01 validator (RFC 8737) connects with ALPN `acme-tls/1`,
inspects the id-pe-acmeIdentifier extension (OID 1.3.6.1.5.5.7.1.31),
asserts the ASN.1 OCTET STRING value equals SHA-256 of the key
authorization. Cert chain is intentionally NOT validated
(InsecureSkipVerify=true is correct per RFC 8737 — the proof is
in the extension, not the chain). Documented in docs/tls.md L-001
table + the //nolint:gosec comment carries the justification.
SSRF guard: same posture as HTTP-01.
- Validation is asynchronous: handler accepts the POST and returns
200 immediately with status=processing; the worker-pool fires a
callback that updates challenge → authz → order in a fresh
background-context WithinTx. The order auto-promotes to `ready`
when ALL authzs become valid; auto-fails to `invalid` when ANY
authz becomes invalid.
What ships:
- internal/api/acme/challenge.go: KeyAuthorization (RFC 8555 §8.1) +
DNS01TXTRecordValue (§8.4) + TLSALPN01ExtensionValue (RFC 8737 §3)
helpers; IDPEAcmeIdentifierOID; ChallengeProblemFromError mapper
(4-way: connection / dns / tls / incorrectResponse); 9 sentinel
errors covering every named failure mode.
- internal/api/acme/validators.go: ChallengeValidator interface;
Pool dispatcher with 3 semaphores + per-type in-flight + peak
gauges; HTTP01Validator + DNS01Validator + TLSALPN01Validator
implementations; Drain method called from cmd/server/main.go's
shutdown sequence.
- internal/api/acme/validators_test.go: KeyAuthorization round-trip,
DNS01 / TLS-ALPN-01 helper tests, SSRF rejection, bounded-
concurrency saturation test (peak-in-flight ≤ cap), type-isolation
test (HTTP-01 saturation doesn't block DNS-01), UnknownType test,
7-case ChallengeProblemFromError mapping.
- internal/repository/postgres/acme.go: GetChallengeByID +
UpdateChallengeWithTx + UpdateAuthzStatusWithTx.
- internal/service/acme.go: SetValidatorPool wires the *acme.Pool;
RespondToChallenge dispatches with account-ownership assertion +
KeyAuthorization computation + processing-status transition (atomic
+ audit); recordChallengeOutcome callback persists the final
challenge + cascading authz + order-promote/-fail in one WithinTx +
audit row. 4 new metrics.
- internal/api/handler/acme.go: Challenge handler; round-trips
account.JWKPEM through ParseJWKFromPEM to recover the *jose.JSONWebKey
the validator pool needs.
- internal/api/router/router.go + openapi_parity_test.go +
api/openapi-handler-exceptions.yaml: 2 new routes (per-profile +
shorthand for challenge/{chall_id}) with parity exceptions.
- cmd/server/main.go: constructs the Pool at startup with the
per-type concurrency caps from cfg.ACMEServer; ACMEService.ValidatorPool()
accessor exposed for the shutdown drain sequence.
- internal/validation/ssrf.go: exported IsReservedIPForDial wrapper
(private impl unchanged; network scanner + ValidateSafeURL paths
byte-identical with prior behavior).
- docs/tls.md: L-001 InsecureSkipVerify table extended with the
TLS-ALPN-01 validator justification (RFC 8737 §3).
- docs/acme-server.md: phase status updated; endpoints table grows
the challenge row; phases-cross-reference flips Phase 3 → live.
Tests:
- 80%+ coverage on the new files.
- BoundedConcurrency test: 10 challenges submitted against an
HTTP-01 pool of weight 3; observed peak-in-flight ≤ 3, all 10
eventually complete, post-Drain in-flight returns to 0.
- TypeIsolation test: HTTP-01 saturation does NOT block a DNS-01
submission; DNS-01 callback fires within 2s.
- SSRF rejection test: a Validate against `localhost` is refused
before the dial (ErrChallengeReservedIP or ErrChallengeConnection).
Engineering history: cowork/WORKSPACE-CHANGELOG.md "ACME-Server-3".
