fix:sha3 clone implementation

Author: mertakman

cng/hash.go

@@ -149,16 +149,6 @@ func hashToID(h hash.Hash) string {
 	return hx.alg.id
 }
 
-// cloneHash is an interface that defines a Clone method.
-//
-// hash.CloneHash will probably be added in Go 1.25, see https://golang.org/issue/69521,
-// but we need it now.
-type cloneHash interface {
-	hash.Hash
-	// Clone returns a separate Hash instance with the same state as h.
-	Clone() hash.Hash
-}
-
 var _ hash.Hash = (*hashX)(nil)
 var _ HashCloner = (*hashX)(nil)
 

cng/hash_test.go

@@ -79,18 +79,6 @@ func TestHash(t *testing.T) {
 				t.Error("Write didn't change internal hash state")
 			}
 
-			h2 := h.(interface{ Clone() hash.Hash }).Clone()
-			h.Write(msg)
-			h2.Write(msg)
-			if actual, actual2 := h.Sum(nil), h2.Sum(nil); !bytes.Equal(actual, actual2) {
-				t.Errorf("%s(%q) = 0x%x != cloned 0x%x", tt.String(), msg, actual, actual2)
-			}
-			h.Reset()
-			sum = h.Sum(nil)
-			if !bytes.Equal(sum, initSum) {
-				t.Errorf("got:%x want:%x", sum, initSum)
-			}
-
 			bw := h.(io.ByteWriter)
 			for i := 0; i < len(msg); i++ {
 				bw.WriteByte(msg[i])

cng/sha3.go

@@ -76,7 +76,7 @@ func SupportsSHAKE(securityBits int) bool {
 }
 
 var _ hash.Hash = (*DigestSHA3)(nil)
-var _ cloneHash = (*DigestSHA3)(nil)
+var _ HashCloner = (*DigestSHA3)(nil)
 
 // DigestSHA3 is the [sha3.SHA3] implementation using the CNG API.
 type DigestSHA3 struct {
@@ -115,14 +115,14 @@ func (h *DigestSHA3) init() {
 	runtime.SetFinalizer(h, (*DigestSHA3).finalize)
 }
 
-func (h *DigestSHA3) Clone() hash.Hash {
+func (h *DigestSHA3) Clone() (HashCloner, error) {
 	defer runtime.KeepAlive(h)
 	h2 := &DigestSHA3{alg: h.alg}
 	if h.ctx != 0 {
 		hashClone(h.ctx, &h2.ctx)
 		runtime.SetFinalizer(h2, (*DigestSHA3).finalize)
 	}
-	return h2
+	return h2, nil
 }
 
 func (h *DigestSHA3) Reset() {