Add LoadOrGenClient to handle client cert generation

factory/cert_utils.go

@@ -40,6 +40,31 @@ func NewSelfSignedCACert(key crypto.Signer, cn string, org ...string) (*x509.Cer
 	return x509.ParseCertificate(certDERBytes)
 }
 
+func NewSignedClientCert(signer crypto.Signer, caCert *x509.Certificate, caKey crypto.Signer, cn string) (*x509.Certificate, error) {
+	serialNumber, err := rand.Int(rand.Reader, new(big.Int).SetInt64(math.MaxInt64))
+	if err != nil {
+		return nil, err
+	}
+
+	parent := x509.Certificate{
+		ExtKeyUsage:  []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
+		KeyUsage:     x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
+		NotAfter:     time.Now().Add(time.Hour * 24 * 365).UTC(),
+		NotBefore:    caCert.NotBefore,
+		SerialNumber: serialNumber,
+		Subject: pkix.Name{
+			CommonName: cn,
+		},
+	}
+
+	cert, err := x509.CreateCertificate(rand.Reader, &parent, caCert, signer.Public(), caKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return x509.ParseCertificate(cert)
+}
+
 func NewSignedCert(signer crypto.Signer, caCert *x509.Certificate, caKey crypto.Signer, cn string, orgs []string,
 	domains []string, ips []net.IP) (*x509.Certificate, error) {
 

storage/kubernetes/ca.go

@@ -19,6 +19,23 @@ func LoadOrGenCA(secrets v1controller.SecretClient, namespace, name string) (*x5
 	return factory.LoadCA(secret.Data[v1.TLSCertKey], secret.Data[v1.TLSPrivateKeyKey])
 }
 
+func LoadOrGenClient(secrets v1controller.SecretClient, namespace, name, cn string, ca *x509.Certificate, key crypto.Signer) (*x509.Certificate, crypto.Signer, error) {
+	secret, err := getClientSecret(secrets, namespace, name, cn, ca, key)
+	if err != nil {
+		return nil, nil, err
+	}
+	return factory.LoadCA(secret.Data[v1.TLSCertKey], secret.Data[v1.TLSPrivateKeyKey])
+}
+
+func getClientSecret(secrets v1controller.SecretClient, namespace, name, cn string, caCert *x509.Certificate, caKey crypto.Signer) (*v1.Secret, error) {
+	s, err := secrets.Get(namespace, name, metav1.GetOptions{})
+	if !errors.IsNotFound(err) {
+		return s, err
+	}
+
+	return createAndStoreClientCert(secrets, namespace, name, cn, caCert, caKey)
+}
+
 func getSecret(secrets v1controller.SecretClient, namespace, name string) (*v1.Secret, error) {
 	s, err := secrets.Get(namespace, name, metav1.GetOptions{})
 	if !errors.IsNotFound(err) {
@@ -28,6 +45,37 @@ func getSecret(secrets v1controller.SecretClient, namespace, name string) (*v1.S
 	return createAndStore(secrets, namespace, name)
 }
 
+func createAndStoreClientCert(secrets v1controller.SecretClient, namespace string, name, cn string, caCert *x509.Certificate, caKey crypto.Signer) (*v1.Secret, error) {
+	key, err := factory.NewPrivateKey()
+	if err != nil {
+		return nil, err
+	}
+
+	cert, err := factory.NewSignedClientCert(key, caCert, caKey, cn)
+	if err != nil {
+		return nil, err
+	}
+
+	certPem, keyPem, err := factory.Marshal(cert, key)
+	if err != nil {
+		return nil, err
+	}
+
+	secret := &v1.Secret{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      name,
+			Namespace: namespace,
+		},
+		Data: map[string][]byte{
+			v1.TLSCertKey:       certPem,
+			v1.TLSPrivateKeyKey: keyPem,
+		},
+		Type: v1.SecretTypeTLS,
+	}
+
+	return secrets.Create(secret)
+}
+
 func createAndStore(secrets v1controller.SecretClient, namespace string, name string) (*v1.Secret, error) {
 	ca, cert, err := factory.GenCA()
 	if err != nil {