Merge pull request #35593 from madhusudancs/federation-kubefed-init-certutil-triple

Automatic merge from submit-queue

Implement package `triple` with utilities to generate certificate-key pairs for CA, server and clients.

Please review only the last commit here. This is based on PRs #35592 which will be reviewed independently.

Design Doc: PR #34484

cc @kubernetes/sig-cluster-federation @quinton-hoole @mwielgus

pkg/util/cert/triple/BUILD

@@ -0,0 +1,18 @@
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_binary",
+    "go_library",
+    "go_test",
+    "cgo_library",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = ["triple.go"],
+    tags = ["automanaged"],
+    deps = ["//pkg/util/cert:go_default_library"],
+)

pkg/util/cert/triple/triple.go

@@ -0,0 +1,113 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package triple generates key-certificate pairs for the
+// triple (CA, Server, Client).
+package triple
+
+import (
+	"crypto/rsa"
+	"crypto/x509"
+	"fmt"
+	"net"
+
+	certutil "k8s.io/kubernetes/pkg/util/cert"
+)
+
+type KeyPair struct {
+	Key  *rsa.PrivateKey
+	Cert *x509.Certificate
+}
+
+func NewCA(name string) (*KeyPair, error) {
+	key, err := certutil.NewPrivateKey()
+	if err != nil {
+		return nil, fmt.Errorf("unable to create a private key for a new CA: %v", err)
+	}
+
+	config := certutil.Config{
+		CommonName: name,
+	}
+
+	cert, err := certutil.NewSelfSignedCACert(config, key)
+	if err != nil {
+		return nil, fmt.Errorf("unable to create a self-signed certificate for a new CA: %v", err)
+	}
+
+	return &KeyPair{
+		Key:  key,
+		Cert: cert,
+	}, nil
+}
+
+func NewServerKeyPair(ca *KeyPair, commonName, svcName, svcNamespace, dnsDomain string, ips, hostnames []string) (*KeyPair, error) {
+	key, err := certutil.NewPrivateKey()
+	if err != nil {
+		return nil, fmt.Errorf("unable to create a server private key: %v", err)
+	}
+
+	namespacedName := fmt.Sprintf("%s.%s", svcName, svcNamespace)
+	internalAPIServerFQDN := []string{
+		svcName,
+		namespacedName,
+		fmt.Sprintf("%s.svc", namespacedName),
+		fmt.Sprintf("%s.svc.%s", namespacedName, dnsDomain),
+	}
+
+	altNames := certutil.AltNames{}
+	for _, ipStr := range ips {
+		ip := net.ParseIP(ipStr)
+		if ip != nil {
+			altNames.IPs = append(altNames.IPs, ip)
+		}
+	}
+	altNames.DNSNames = append(altNames.DNSNames, hostnames...)
+	altNames.DNSNames = append(altNames.DNSNames, internalAPIServerFQDN...)
+
+	config := certutil.Config{
+		CommonName: commonName,
+		AltNames:   altNames,
+	}
+	cert, err := certutil.NewSignedCert(config, key, ca.Cert, ca.Key)
+	if err != nil {
+		return nil, fmt.Errorf("unable to sign the server certificate: %v", err)
+	}
+
+	return &KeyPair{
+		Key:  key,
+		Cert: cert,
+	}, nil
+}
+
+func NewClientKeyPair(ca *KeyPair, commonName string) (*KeyPair, error) {
+	key, err := certutil.NewPrivateKey()
+	if err != nil {
+		return nil, fmt.Errorf("unable to create a client private key: %v", err)
+	}
+
+	config := certutil.Config{
+		CommonName: commonName,
+	}
+	cert, err := certutil.NewSignedCert(config, key, ca.Cert, ca.Key)
+	if err != nil {
+		return nil, fmt.Errorf("unable to sign the client certificate: %v", err)
+	}
+
+	return &KeyPair{
+		Key:  key,
+		Cert: cert,
+	}, nil
+}