forked from sassoftware/relic
/
x509cmd.go
340 lines (319 loc) · 10.7 KB
/
x509cmd.go
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//
// Copyright (c) SAS Institute Inc.
//
// 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 x509tools
import (
"bytes"
"crypto"
"crypto/rand"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"errors"
"fmt"
"io"
"math/big"
"os"
"strings"
"time"
"github.com/spf13/cobra"
"golang.org/x/crypto/ssh/terminal"
)
var (
ArgCountry string
ArgOrganization string
ArgOrganizationalUnit string
ArgLocality string
ArgProvince string
ArgCommonName string
ArgDNSNames string
ArgEmailNames string
ArgKeyUsage string
ArgExpireDays uint
ArgCertAuthority bool
ArgSerial string
ArgInteractive bool
ArgRSAPSS bool
)
// Add flags associated with X509 requests to the given command
func AddRequestFlags(cmd *cobra.Command) {
cmd.Flags().StringVar(&ArgCountry, "countryName", "", "Subject name")
cmd.Flags().StringVar(&ArgProvince, "stateOrProvinceName", "", "Subject name")
cmd.Flags().StringVar(&ArgLocality, "localityName", "", "Subject name")
cmd.Flags().StringVar(&ArgOrganization, "organizationName", "", "Subject name")
cmd.Flags().StringVar(&ArgOrganizationalUnit, "organizationalUnitName", "", "Subject name")
cmd.Flags().StringVarP(&ArgCommonName, "commonName", "n", "", "Subject commonName")
cmd.Flags().StringVar(&ArgDNSNames, "alternate-dns", "", "DNS subject alternate name (comma or space separated)")
cmd.Flags().StringVar(&ArgEmailNames, "alternate-email", "", "Email subject alternate name (comma or space separated)")
cmd.Flags().BoolVarP(&ArgInteractive, "interactive", "i", false, "Prompt before signing certificate")
cmd.Flags().BoolVar(&ArgRSAPSS, "rsa-pss", false, "Use RSA-PSS signature")
}
// Add flags associated with X509 certificate creation to the given command
func AddCertFlags(cmd *cobra.Command) {
AddRequestFlags(cmd)
cmd.Flags().BoolVar(&ArgCertAuthority, "cert-authority", false, "If this certificate is an authority")
cmd.Flags().StringVarP(&ArgKeyUsage, "key-usage", "U", "", "Key usage, one of: serverAuth clientAuth codeSigning emailProtection keyCertSign")
cmd.Flags().UintVarP(&ArgExpireDays, "expire-days", "e", 36523, "Number of days before certificate expires")
cmd.Flags().StringVar(&ArgSerial, "serial", "", "Set the serial number of the certificate. Random if not specified.")
}
// Split a space- and/or comma-seperated string
func splitAndTrim(s string) []string {
if s == "" {
return nil
}
s = strings.Replace(s, ",", " ", -1)
pieces := strings.Split(s, " ")
ret := make([]string, 0, len(pieces))
for _, p := range pieces {
p = strings.Trim(p, " ")
if p != "" {
ret = append(ret, p)
}
}
return ret
}
// Build a subject name from command-line arguments
func subjName() (name pkix.Name) {
if ArgCountry != "" {
name.Country = []string{ArgCountry}
}
if ArgProvince != "" {
name.Province = []string{ArgProvince}
}
if ArgLocality != "" {
name.Locality = []string{ArgLocality}
}
if ArgOrganization != "" {
name.Organization = []string{ArgOrganization}
}
if ArgOrganizationalUnit != "" {
name.OrganizationalUnit = []string{ArgOrganizationalUnit}
}
name.CommonName = ArgCommonName
return
}
// Set both basic and extended key usage
func setUsage(template *x509.Certificate) error {
usage := x509.KeyUsageDigitalSignature
var extended []x509.ExtKeyUsage
switch strings.ToLower(ArgKeyUsage) {
case "serverauth":
usage |= x509.KeyUsageKeyEncipherment | x509.KeyUsageKeyAgreement
extended = append(extended, x509.ExtKeyUsageServerAuth)
case "clientauth":
usage |= x509.KeyUsageKeyEncipherment | x509.KeyUsageKeyAgreement
extended = append(extended, x509.ExtKeyUsageClientAuth)
case "codesigning":
extended = append(extended, x509.ExtKeyUsageCodeSigning)
case "emailprotection":
usage |= x509.KeyUsageContentCommitment | x509.KeyUsageKeyEncipherment | x509.KeyUsageKeyAgreement
extended = append(extended, x509.ExtKeyUsageEmailProtection)
case "keycertsign":
usage |= x509.KeyUsageCertSign | x509.KeyUsageCRLSign
case "":
return nil
default:
return errors.New("invalid key-usage")
}
template.KeyUsage = usage
template.ExtKeyUsage = extended
return nil
}
func fillCertFields(template *x509.Certificate, subjectPub, issuerPub crypto.PublicKey) error {
if ArgSerial != "" {
serial, ok := new(big.Int).SetString(ArgSerial, 0)
if !ok {
return errors.New("invalid serial number, must be decimal or hexadecimal format")
}
template.SerialNumber = serial
} else if template.SerialNumber == nil {
template.SerialNumber = MakeSerial()
if template.SerialNumber == nil {
return errors.New("Failed to generate a serial number")
}
}
if ArgCommonName != "" {
template.Subject = subjName()
}
if ArgDNSNames != "" {
template.DNSNames = splitAndTrim(ArgDNSNames)
}
if ArgEmailNames != "" {
template.EmailAddresses = splitAndTrim(ArgEmailNames)
}
template.SignatureAlgorithm = X509SignatureAlgorithm(issuerPub)
template.NotBefore = time.Now().Add(time.Hour * -24)
template.NotAfter = time.Now().Add(time.Hour * 24 * time.Duration(ArgExpireDays))
template.IsCA = ArgCertAuthority
template.BasicConstraintsValid = true
ski, err := SubjectKeyID(subjectPub)
if err != nil {
return err
}
template.SubjectKeyId = ski
return setUsage(template)
}
func toPemString(der []byte, pemType string) string {
block := &pem.Block{Type: pemType, Bytes: der}
return string(pem.EncodeToMemory(block))
}
// Make a X509 certificate request using command-line arguments and return the
// PEM string
func MakeRequest(rand io.Reader, key crypto.Signer) (string, error) {
var template x509.CertificateRequest
template.Subject = subjName()
template.DNSNames = splitAndTrim(ArgDNSNames)
template.EmailAddresses = splitAndTrim(ArgEmailNames)
template.SignatureAlgorithm = X509SignatureAlgorithm(key.Public())
csr, err := x509.CreateCertificateRequest(rand, &template, key)
if err != nil {
return "", err
}
return toPemString(csr, "CERTIFICATE REQUEST"), nil
}
// Make a self-signed X509 certificate using command-line arguments and return
// the PEM string
func MakeCertificate(rand io.Reader, key crypto.Signer) (string, error) {
var template x509.Certificate
if err := fillCertFields(&template, key.Public(), key.Public()); err != nil {
return "", err
}
template.Issuer = template.Subject
cert, err := confirmAndCreate(&template, &template, key.Public(), key)
if err != nil {
return "", err
}
return toPemString(cert, "CERTIFICATE"), nil
}
// SignCSR takes a PKCS#10 signing request in PEM or DER format as input and
// produces a signed certificate in PEM format. Any command-line flags set will
// override the CSR contents.
func SignCSR(csrBytes []byte, rand io.Reader, key crypto.Signer, cacert *x509.Certificate, copyExtensions bool) (string, error) {
// parse and validate CSR
csrBytes, err := parseMaybePEM(csrBytes, "CERTIFICATE REQUEST")
if err != nil {
return "", err
}
csr, err := x509.ParseCertificateRequest(csrBytes)
if err != nil {
return "", fmt.Errorf("parsing CSR: %s", err)
}
if err := csr.CheckSignature(); err != nil {
return "", fmt.Errorf("validating CSR: %s", err)
}
// update fields
template := &x509.Certificate{Subject: csr.Subject}
if copyExtensions {
template.ExtraExtensions = csr.Extensions
template.DNSNames = csr.DNSNames
template.EmailAddresses = csr.EmailAddresses
template.IPAddresses = csr.IPAddresses
template.URIs = csr.URIs
}
if err := fillCertFields(template, csr.PublicKey, key.Public()); err != nil {
return "", err
}
certDer, err := confirmAndCreate(template, cacert, csr.PublicKey, key)
if err != nil {
return "", err
}
return toPemString(certDer, "CERTIFICATE"), nil
}
// CrossSign takes a certificate as input and re-signs it using the given key.
// Any command-line flags set will override the CSR contents.
func CrossSign(certBytes []byte, rand io.Reader, key crypto.Signer, cacert *x509.Certificate) (string, error) {
certBytes, err := parseMaybePEM(certBytes, "CERTIFICATE")
if err != nil {
return "", err
}
template, err := x509.ParseCertificate(certBytes)
if err != nil {
return "", fmt.Errorf("parsing certificate: %s", err)
}
if err := fillCertFields(template, template.PublicKey, key.Public()); err != nil {
return "", err
}
newCert, err := confirmAndCreate(template, cacert, template.PublicKey, key)
if err != nil {
return "", err
}
return toPemString(newCert, "CERTIFICATE"), nil
}
type fakeSigner struct{ pub crypto.PublicKey }
func (f fakeSigner) Public() crypto.PublicKey {
return f.pub
}
func (f fakeSigner) Sign(io.Reader, []byte, crypto.SignerOpts) ([]byte, error) {
return nil, nil
}
func confirmAndCreate(template, parent *x509.Certificate, pub crypto.PublicKey, priv crypto.PrivateKey) ([]byte, error) {
if ArgInteractive {
// call CreateCertificate with a fake signer to get what the final cert will look like
pub := priv.(crypto.Signer).Public()
der, err := x509.CreateCertificate(rand.Reader, template, parent, pub, fakeSigner{pub})
if err != nil {
return nil, err
}
cert, err := x509.ParseCertificate(der)
if err != nil {
return nil, err
}
fmt.Fprintln(os.Stderr, "Signing certificate:")
fmt.Fprintln(os.Stderr)
FprintCertificate(os.Stderr, cert)
fmt.Fprintln(os.Stderr)
if !promptYN("Sign this cert? [Y/n] ") {
fmt.Fprintln(os.Stderr, "operation canceled")
os.Exit(2)
}
}
return x509.CreateCertificate(rand.Reader, template, parent, pub, priv)
}
func promptYN(prompt string) bool {
fmt.Fprint(os.Stderr, prompt)
if !terminal.IsTerminal(0) {
fmt.Fprintln(os.Stderr, "input is not a terminal, assuming true")
return true
}
state, err := terminal.MakeRaw(0)
if err == nil {
defer fmt.Fprintln(os.Stderr)
defer terminal.Restore(0, state)
}
var d [1]byte
if _, err := os.Stdin.Read(d[:]); err != nil {
return false
}
if d[0] == 'Y' || d[0] == 'y' {
return true
}
return false
}
func parseMaybePEM(blob []byte, pemType string) ([]byte, error) {
if bytes.Contains(blob, []byte("-----BEGIN")) {
for {
var block *pem.Block
block, blob = pem.Decode(blob)
if block == nil {
break
} else if block.Type == pemType {
return block.Bytes, nil
}
}
} else if len(blob) > 0 && blob[0] == 0x30 {
return blob, nil
}
return nil, fmt.Errorf("expected a %s in PEM or DER format", strings.ToLower(pemType))
}