webserver will now automatically create a certificate for itself if no certificates are defined.

internal/certificate/create-cert.go

@@ -0,0 +1,71 @@
+package certificate
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"math/big"
+	"strconv"
+	"time"
+)
+
+func CreateCert() ([]byte, []byte, []byte, error) {
+	serial, _ := strconv.ParseInt(time.Now().Format("20060102150405"), 10, 64)
+	ca := &x509.Certificate{
+		SerialNumber: big.NewInt(serial + 1),
+		Subject: pkix.Name{
+			Organization: []string{"Kubernetes Mutating Webserver"},
+			Country:      []string{"K8S"},
+			Province:     []string{"Cluster Service"},
+			Locality:     []string{"Cluster Local"},
+			//StreetAddress: []string{""},
+			//PostalCode:    []string{""},
+		},
+		NotBefore: time.Now(),
+		NotAfter:  time.Now().AddDate(1, 6, 0),
+		ExtKeyUsage: []x509.ExtKeyUsage{
+			x509.ExtKeyUsageClientAuth,
+			x509.ExtKeyUsageServerAuth,
+		},
+		DNSNames: []string{
+			"svc.cluster.local",
+			"*.svc.cluster.local",
+		},
+		SubjectKeyId:       []byte{1, 2, 3, 4, 6},
+		KeyUsage:           x509.KeyUsageDigitalSignature,
+		SignatureAlgorithm: x509.SHA384WithRSA,
+	}
+
+	keyPair, err := rsa.GenerateKey(rand.Reader, 4096)
+	if err != nil {
+		return []byte(""), []byte(""), []byte(""), err
+	}
+
+	certBytes, err := x509.CreateCertificate(rand.Reader, ca, ca, &keyPair.PublicKey, keyPair)
+	if err != nil {
+		return []byte(""), []byte(""), []byte(""), err
+	}
+
+	c := new(bytes.Buffer)
+	pem.Encode(c, &pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: certBytes,
+	})
+
+	k := new(bytes.Buffer)
+	pem.Encode(k, &pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: x509.MarshalPKCS1PrivateKey(keyPair),
+	})
+
+	p := new(bytes.Buffer)
+	pem.Encode(p, &pem.Block{
+		Type:  "PUBLIC KEY",
+		Bytes: x509.MarshalPKCS1PublicKey(&keyPair.PublicKey),
+	})
+
+	return c.Bytes(), k.Bytes(), p.Bytes(), nil
+}