Add Identity helpers.

ca/client.go

@@ -26,6 +26,7 @@ import (
 	"github.com/smallstep/certificates/authority"
 	"github.com/smallstep/certificates/authority/provisioner"
 	"github.com/smallstep/cli/config"
+	"github.com/smallstep/cli/crypto/keys"
 	"github.com/smallstep/cli/crypto/x509util"
 	"golang.org/x/net/http2"
 	"gopkg.in/square/go-jose.v2/jwt"
@@ -1033,6 +1034,44 @@ func CreateSignRequest(ott string) (*api.SignRequest, crypto.PrivateKey, error)
 	}, pk, nil
 }
 
+// CreateCertificateRequest creates a new CSR with the given common name and
+// SANs. If no san is provided the commonName will set also a SAN.
+func CreateCertificateRequest(commonName string, sans ...string) (*api.CertificateRequest, crypto.PrivateKey, error) {
+	key, err := keys.GenerateDefaultKey()
+	if err != nil {
+		return nil, nil, err
+	}
+	return createCertificateRequest(commonName, sans, key)
+}
+
+func createCertificateRequest(commonName string, sans []string, key crypto.PrivateKey) (*api.CertificateRequest, crypto.PrivateKey, error) {
+	if len(sans) == 0 {
+		sans = []string{commonName}
+	}
+	dnsNames, ips, emails := x509util.SplitSANs(sans)
+	template := &x509.CertificateRequest{
+		Subject: pkix.Name{
+			CommonName: commonName,
+		},
+		DNSNames:       dnsNames,
+		IPAddresses:    ips,
+		EmailAddresses: emails,
+	}
+	csr, err := x509.CreateCertificateRequest(rand.Reader, template, key)
+	if err != nil {
+		return nil, nil, err
+	}
+	cr, err := x509.ParseCertificateRequest(csr)
+	if err != nil {
+		return nil, nil, err
+	}
+	if err := cr.CheckSignature(); err != nil {
+		return nil, nil, err
+	}
+
+	return &api.CertificateRequest{CertificateRequest: cr}, key, nil
+}
+
 func getInsecureClient() *http.Client {
 	return &http.Client{
 		Transport: &http.Transport{

ca/identity.go

@@ -40,6 +40,21 @@ type Identity struct {
 	Key         string `json:"key"`
 }
 
+// NewIdentityRequest returns a new CSR to create the identity. If an identity
+// was already present it reuses the private key.
+func NewIdentityRequest(commonName string, sans ...string) (*api.CertificateRequest, crypto.PrivateKey, error) {
+	var identityKey crypto.PrivateKey
+	if i, err := LoadDefaultIdentity(); err == nil && i.Key != "" {
+		if k, err := pemutil.Read(i.Key); err == nil {
+			identityKey = k
+		}
+	}
+	if identityKey == nil {
+		return CreateCertificateRequest(commonName, sans...)
+	}
+	return createCertificateRequest(commonName, sans, identityKey)
+}
+
 // LoadDefaultIdentity loads the default identity.
 func LoadDefaultIdentity() (*Identity, error) {
 	b, err := ioutil.ReadFile(IdentityFile)