cmd/sign: make it possible to specify additional extended key usage

cmd/oid.go

@@ -0,0 +1,20 @@
+package cmd
+
+import (
+	"encoding/asn1"
+	"strconv"
+	"strings"
+)
+
+func parseOid(oid string) (asn1.ObjectIdentifier, error) {
+	result := make([]int, 0)
+	for _, part := range strings.Split(oid, ".") {
+		number, err := strconv.ParseInt(part, 10, 32)
+		if err != nil {
+			return asn1.ObjectIdentifier{}, err
+		}
+		result = append(result, int(number))
+	}
+
+	return asn1.ObjectIdentifier(result), nil
+}

cmd/oid_test.go

@@ -0,0 +1,22 @@
+package cmd
+
+import (
+	"encoding/asn1"
+	"testing"
+)
+
+func TestValidOid(t *testing.T) {
+	parsed, _ := parseOid("1.3.6.1.5.5.7.3.1")
+	expected := asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 3, 1}
+
+	if !parsed.Equal(expected) {
+		t.Fatalf("Parsed OID does not match expected (expected: %s, got %s)", expected, parsed)
+	}
+}
+
+func TestInvalidOid(t *testing.T) {
+	_, err := parseOid("not an OID")
+	if err == nil {
+		t.Fatalf("Expected error when parsing invalid OID")
+	}
+}

cmd/revoke_test.go

@@ -113,7 +113,7 @@ func setupCN(t *testing.T, dt depot.Depot) {
 		t.Fatalf("could not get cert: %v", err)
 	}
 
-	cnCert, err := pkix.CreateCertificateHost(caCert, key, csr, time.Now().Add(1*time.Hour))
+	cnCert, err := pkix.CreateCertificateHost(caCert, key, csr, time.Now().Add(1*time.Hour), nil)
 	if err != nil {
 		t.Fatalf("could not create cert host: %v", err)
 	}

cmd/sign.go

@@ -18,6 +18,7 @@
 package cmd
 
 import (
+	"encoding/asn1"
 	"fmt"
 	"os"
 	"strings"
@@ -67,6 +68,10 @@ func NewSignCommand() cli.Command {
 				Name:  "intermediate",
 				Usage: "Whether generated certificate should be a intermediate",
 			},
+			cli.StringFlag{
+				Name:  "extended-key-usage",
+				Usage: "OID of additional Extended Key Usage value to add to the certificate (example: 1.3.6.1.5.5.7.3.1)",
+			},
 		},
 		Action: newSignAction,
 	}
@@ -99,6 +104,17 @@ func newSignAction(c *cli.Context) {
 		os.Exit(1)
 	}
 
+	additionalExtendedKeyUsages := make([]asn1.ObjectIdentifier, 0)
+	additionalExtendedKeyUsage := c.String("extended-key-usage")
+	if additionalExtendedKeyUsage != "" {
+		oid, err := parseOid(additionalExtendedKeyUsage)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "Invalid OID value:", err)
+			os.Exit(1)
+		}
+		additionalExtendedKeyUsages = append(additionalExtendedKeyUsages, oid)
+	}
+
 	csr, err := getCertificateSigningRequest(c, d, formattedReqName)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "Get certificate request error:", err)
@@ -142,7 +158,7 @@ func newSignAction(c *cli.Context) {
 		fmt.Fprintln(os.Stderr, "Building intermediate")
 		crtOut, err = pkix.CreateIntermediateCertificateAuthority(crt, key, csr, expiresTime)
 	} else {
-		crtOut, err = pkix.CreateCertificateHost(crt, key, csr, expiresTime)
+		crtOut, err = pkix.CreateCertificateHost(crt, key, csr, expiresTime, additionalExtendedKeyUsages)
 	}
 
 	if err != nil {

pkix/cert_host.go

@@ -21,13 +21,14 @@ import (
 	"crypto/rand"
 	"crypto/x509"
 	"crypto/x509/pkix"
+	"encoding/asn1"
 	"math/big"
 	"time"
 )
 
 // CreateCertificateHost creates certificate for host.
 // The arguments include CA certificate, CA key, certificate request.
-func CreateCertificateHost(crtAuth *Certificate, keyAuth *Key, csr *CertificateSigningRequest, proposedExpiry time.Time) (*Certificate, error) {
+func CreateCertificateHost(crtAuth *Certificate, keyAuth *Key, csr *CertificateSigningRequest, proposedExpiry time.Time, extendedKeyUsages []asn1.ObjectIdentifier) (*Certificate, error) {
 	// Build CA based on RFC5280
 	hostTemplate := x509.Certificate{
 		// **SHOULD** be filled in a unique number
@@ -45,7 +46,7 @@ func CreateCertificateHost(crtAuth *Certificate, keyAuth *Key, csr *CertificateS
 			x509.ExtKeyUsageServerAuth,
 			x509.ExtKeyUsageClientAuth,
 		},
-		UnknownExtKeyUsage: nil,
+		UnknownExtKeyUsage: extendedKeyUsages,
 
 		BasicConstraintsValid: false,
 

pkix/cert_host_test.go

@@ -39,7 +39,7 @@ func TestCreateCertificateHost(t *testing.T) {
 		t.Fatal("Failed parsing certificate request from PEM:", err)
 	}
 
-	crt, err := CreateCertificateHost(crtAuth, key, csr, time.Now().AddDate(5000, 0, 0))
+	crt, err := CreateCertificateHost(crtAuth, key, csr, time.Now().AddDate(5000, 0, 0), nil)
 	if err != nil {
 		t.Fatal("Failed creating certificate for host:", err)
 	}