Split self-signed cert and CA

staging/src/k8s.io/client-go/util/cert/cert.go

@@ -138,23 +138,50 @@ func MakeEllipticPrivateKeyPEM() ([]byte, error) {
 // Host may be an IP or a DNS name
 // You may also specify additional subject alt names (either ip or dns names) for the certificate
 func GenerateSelfSignedCertKey(host string, alternateIPs []net.IP, alternateDNS []string) ([]byte, []byte, error) {
+	caKey, err := rsa.GenerateKey(cryptorand.Reader, 2048)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	caTemplate := x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: fmt.Sprintf("%s-ca@%d", host, time.Now().Unix()),
+		},
+		NotBefore: time.Now(),
+		NotAfter:  time.Now().Add(time.Hour * 24 * 365),
+
+		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
+		BasicConstraintsValid: true,
+		IsCA: true,
+	}
+
+	caDERBytes, err := x509.CreateCertificate(cryptorand.Reader, &caTemplate, &caTemplate, &caKey.PublicKey, caKey)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	caCertificate, err := x509.ParseCertificate(caDERBytes)
+	if err != nil {
+		return nil, nil, err
+	}
+
 	priv, err := rsa.GenerateKey(cryptorand.Reader, 2048)
 	if err != nil {
 		return nil, nil, err
 	}
 
 	template := x509.Certificate{
-		SerialNumber: big.NewInt(1),
+		SerialNumber: big.NewInt(2),
 		Subject: pkix.Name{
 			CommonName: fmt.Sprintf("%s@%d", host, time.Now().Unix()),
 		},
 		NotBefore: time.Now(),
 		NotAfter:  time.Now().Add(time.Hour * 24 * 365),
 
-		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
+		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
 		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
 		BasicConstraintsValid: true,
-		IsCA: true,
 	}
 
 	if ip := net.ParseIP(host); ip != nil {
@@ -166,16 +193,19 @@ func GenerateSelfSignedCertKey(host string, alternateIPs []net.IP, alternateDNS
 	template.IPAddresses = append(template.IPAddresses, alternateIPs...)
 	template.DNSNames = append(template.DNSNames, alternateDNS...)
 
-	derBytes, err := x509.CreateCertificate(cryptorand.Reader, &template, &template, &priv.PublicKey, priv)
+	derBytes, err := x509.CreateCertificate(cryptorand.Reader, &template, caCertificate, &priv.PublicKey, caKey)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	// Generate cert
+	// Generate cert, followed by ca
 	certBuffer := bytes.Buffer{}
 	if err := pem.Encode(&certBuffer, &pem.Block{Type: CertificateBlockType, Bytes: derBytes}); err != nil {
 		return nil, nil, err
 	}
+	if err := pem.Encode(&certBuffer, &pem.Block{Type: CertificateBlockType, Bytes: caDERBytes}); err != nil {
+		return nil, nil, err
+	}
 
 	// Generate key
 	keyBuffer := bytes.Buffer{}