Add method to renew the identity.

ca/identity/identity.go

@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"encoding/pem"
 	"io/ioutil"
+	"net/http"
 	"os"
 	"path/filepath"
 	"strings"
@@ -191,6 +192,62 @@ func (i *Identity) TLSCertificate() (tls.Certificate, error) {
 	}
 }
 
+// Renewer is that interface that a renew client must implement.
+type Renewer interface {
+	GetRootCAs() *x509.CertPool
+	Renew(tr http.RoundTripper) (*api.SignResponse, error)
+}
+
+// Renew renews the current identity certificate using a client with a renew
+// method.
+func (i *Identity) Renew(client Renewer) error {
+	switch i.Kind() {
+	case Disabled:
+		return nil
+	case MutualTLS:
+		cert, err := i.TLSCertificate()
+		if err != nil {
+			return err
+		}
+
+		tr := http.DefaultTransport.(*http.Transport).Clone()
+		tr.TLSClientConfig = &tls.Config{
+			Certificates:             []tls.Certificate{cert},
+			RootCAs:                  client.GetRootCAs(),
+			PreferServerCipherSuites: true,
+		}
+
+		sign, err := client.Renew(tr)
+		if err != nil {
+			return err
+		}
+
+		if sign.CertChainPEM == nil || len(sign.CertChainPEM) == 0 {
+			sign.CertChainPEM = []api.Certificate{sign.ServerPEM, sign.CaPEM}
+		}
+
+		// Write certificate
+		buf := new(bytes.Buffer)
+		for _, crt := range sign.CertChainPEM {
+			block := &pem.Block{
+				Type:  "CERTIFICATE",
+				Bytes: crt.Raw,
+			}
+			if err := pem.Encode(buf, block); err != nil {
+				return errors.Wrap(err, "error encoding identity certificate")
+			}
+		}
+		certFilename := filepath.Join(identityDir, "identity.crt")
+		if err := ioutil.WriteFile(certFilename, buf.Bytes(), 0600); err != nil {
+			return errors.Wrap(err, "error writing identity certificate")
+		}
+
+		return nil
+	default:
+		return errors.Errorf("unsupported identity type %s", i.Type)
+	}
+}
+
 func fileExists(filename string) error {
 	info, err := os.Stat(filename)
 	if err != nil {

ca/identity/identity_test.go

@@ -3,15 +3,17 @@ package identity
 import (
 	"crypto"
 	"crypto/tls"
+	"crypto/x509"
+	"fmt"
 	"io/ioutil"
+	"net/http"
 	"os"
 	"path/filepath"
 	"reflect"
 	"testing"
 
-	"github.com/smallstep/cli/crypto/pemutil"
-
 	"github.com/smallstep/certificates/api"
+	"github.com/smallstep/cli/crypto/pemutil"
 )
 
 func TestLoadDefaultIdentity(t *testing.T) {
@@ -252,3 +254,97 @@ func TestWriteDefaultIdentity(t *testing.T) {
 		})
 	}
 }
+
+type renewer struct {
+	pool *x509.CertPool
+	sign *api.SignResponse
+	err  error
+}
+
+func (r *renewer) GetRootCAs() *x509.CertPool {
+	return r.pool
+}
+
+func (r *renewer) Renew(tr http.RoundTripper) (*api.SignResponse, error) {
+	return r.sign, r.err
+}
+
+func TestIdentity_Renew(t *testing.T) {
+	tmpDir, err := ioutil.TempDir(os.TempDir(), "go-tests")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	oldIdentityDir := identityDir
+	defer func() {
+		identityDir = oldIdentityDir
+		os.RemoveAll(tmpDir)
+	}()
+
+	certs, err := pemutil.ReadCertificateBundle("testdata/identity/identity.crt")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ok := &renewer{
+		sign: &api.SignResponse{
+			ServerPEM: api.Certificate{Certificate: certs[0]},
+			CaPEM:     api.Certificate{Certificate: certs[1]},
+			CertChainPEM: []api.Certificate{
+				{Certificate: certs[0]},
+				{Certificate: certs[1]},
+			},
+		},
+	}
+
+	okOld := &renewer{
+		sign: &api.SignResponse{
+			ServerPEM: api.Certificate{Certificate: certs[0]},
+			CaPEM:     api.Certificate{Certificate: certs[1]},
+		},
+	}
+
+	fail := &renewer{
+		err: fmt.Errorf("an error"),
+	}
+
+	type fields struct {
+		Type        string
+		Certificate string
+		Key         string
+	}
+	type args struct {
+		client Renewer
+	}
+	tests := []struct {
+		name    string
+		prepare func()
+		fields  fields
+		args    args
+		wantErr bool
+	}{
+		{"ok", func() {}, fields{"mTLS", "testdata/identity/identity.crt", "testdata/identity/identity_key"}, args{ok}, false},
+		{"ok old", func() {}, fields{"mTLS", "testdata/identity/identity.crt", "testdata/identity/identity_key"}, args{okOld}, false},
+		{"ok disabled", func() {}, fields{}, args{nil}, false},
+		{"fail type", func() {}, fields{"foo", "testdata/identity/identity.crt", "testdata/identity/identity_key"}, args{ok}, true},
+		{"fail renew", func() {}, fields{"mTLS", "testdata/identity/identity.crt", "testdata/identity/identity_key"}, args{fail}, true},
+		{"fail certificate", func() {}, fields{"mTLS", "testdata/certs/server.crt", "testdata/identity/identity_key"}, args{ok}, true},
+		{"fail write identity", func() {
+			identityDir = filepath.Join(tmpDir, "bad-dir")
+			os.MkdirAll(identityDir, 0600)
+		}, fields{"mTLS", "testdata/identity/identity.crt", "testdata/identity/identity_key"}, args{ok}, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tt.prepare()
+			i := &Identity{
+				Type:        tt.fields.Type,
+				Certificate: tt.fields.Certificate,
+				Key:         tt.fields.Key,
+			}
+			if err := i.Renew(tt.args.client); (err != nil) != tt.wantErr {
+				t.Errorf("Identity.Renew() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}