Lint-only fix; no behavior change. ecdsa.PublicKey embeds elliptic.Curve,
so Params() resolves through the embedded field directly. The original
k.Curve.Params() form was correct but flagged by staticcheck QF1008
('could remove embedded field Curve from selector').
Caught by CI #320 (golangci-lint step) after the merge of 68856cb went
green on local 'go vet + go test'. Same class of incident as the
Bundle 9 ST1018 issue documented in CLAUDE.md::Operating Rules — the
'pre-commit verification gate' rule (run make verify, which includes
staticcheck) is the existing defense; the sandbox didn't have
golangci-lint pre-installed which is why this slipped past local
verification.
This is a load-bearing internal refactor with no user-visible behavior
change. The new internal/crypto/signer package abstracts CA private-key
signing behind a Signer interface (embeds stdlib crypto.Signer + adds
Algorithm()). The local issuer now consumes this interface; the
historical c.caKey crypto.Signer field is renamed c.caSigner signer.Signer.
What landed:
* internal/crypto/signer/ — new stdlib-only package
- Signer interface: crypto.Signer + Algorithm()
- Algorithm enum: RSA-2048, RSA-3072, RSA-4096, ECDSA-P256, ECDSA-P384
- Driver interface: Load / Generate / Name
- FileDriver: production driver, wraps file-on-disk PEM, hooks for
DirHardener + Marshaler so the local package can inject Bundle 9
keystore.ensureKeyDirSecure + keymem.marshalPrivateKeyAndZeroize
- MemoryDriver: in-memory test driver; safe for concurrent use
- parse.go: ParsePrivateKey moved here from local.go (PKCS#1, SEC 1, PKCS#8)
- 91.6% coverage (gate ≥85)
* internal/connector/issuer/local/local.go — refactor
- Rename c.caKey crypto.Signer → c.caSigner signer.Signer
- Rewire 4 signing call sites: leaf cert (line ~613), CRL (~849),
OCSP response (~887), CA bootstrap (~482) — all access the
interface; the bootstrap also switches to interface-level
Public() + Signer
- Wrap freshly-generated and freshly-loaded keys; reject Ed25519
and other unsupported algorithms at load time (was silently
accepted before, would have failed at first sign)
- Delete the duplicated parsePrivateKey helper (single source of
truth now lives in the signer package)
- Update the L-014 threat-model comment block (lines 1-29) with a
forward-reference paragraph: file-on-disk caveats apply only to
FileDriver-backed signers; alternative drivers close that leg
- Coverage 86.7 → 86.5 (above CI floor of 86); the 0.2pp drop is
mechanical from deleting parsePrivateKey, partially recovered by
a new test pinning the Wrap error path
* internal/crypto/signer/equivalence_test.go — Phase 3 safety net
- RSA byte-strict equality for leaf certs / CRLs / OCSP responses
(PKCS#1 v1.5 is deterministic)
- ECDSA TBS-strict equality (signature differs because of random k)
- Both signatures independently validate against the CA
- Negative sentinel proves the equivalence checker isn't trivially-
passing
* docs/architecture.md — new 'CA Signing Abstraction' section under
Security Model, with ASCII diagram of FileDriver / MemoryDriver /
future PKCS11Driver / future CloudKMSDriver
* Test file mechanical edits (only):
- bundle9_coverage_test.go: parsePrivateKey → signer.ParsePrivateKey
(function moved, not behavior changed)
- local_test.go: append one targeted test
(TestSubCA_LoadCAFromDisk_RejectsUnsupportedKeyAlgorithm) that
pins the new Wrap error path I introduced — recovers coverage
cost of the deletion above
What did NOT change (verified empty diffs):
* api/openapi.yaml
* migrations/
* internal/connector/issuer/interface.go
* go.mod / go.sum (no new dependencies; stdlib only)
This refactor is the prerequisite for three downstream items:
- PKCS#11/HSM driver (V3-Pro)
- CRL/OCSP responder (V2)
- SSH CA lifecycle (V2)
Each of those adds a new signing call site. Doing the abstraction now
costs once; deferring would cost three times.
Shankar