func GenerateCertifcate(pkiroot, name string, template *x509.Certificate) error {
// TODO(jclerc): check that pki has been init
var crtPath string
privateKeyPath := filepath.Join(pkiroot, "private", name+".key")
if name == "ca" {
crtPath = filepath.Join(pkiroot, name+".crt")
} else {
crtPath = filepath.Join(pkiroot, "issued", name+".crt")
}
var caCrt *x509.Certificate
var caKey *rsa.PrivateKey
if _, err := os.Stat(privateKeyPath); err == nil {
return fmt.Errorf("a key pair for %v already exists", name)
}
privateKey, err := GeneratePrivateKey(privateKeyPath)
if err != nil {
return fmt.Errorf("generate private key: %v", err)
}
publicKeyBytes, err := asn1.Marshal(*privateKey.Public().(*rsa.PublicKey))
if err != nil {
return fmt.Errorf("marshal public key: %v", err)
}
subjectKeyId := sha1.Sum(publicKeyBytes)
template.SubjectKeyId = subjectKeyId[:]
template.NotBefore = time.Now()
template.SignatureAlgorithm = x509.SHA256WithRSA
if template.IsCA {
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
return fmt.Errorf("failed to generate ca serial number: %s", err)
}
template.SerialNumber = serialNumber
template.KeyUsage = x509.KeyUsageCertSign | x509.KeyUsageCRLSign
template.BasicConstraintsValid = true
template.Issuer = template.Subject
template.AuthorityKeyId = template.SubjectKeyId
caCrt = template
caKey = privateKey
} else {
template.KeyUsage = x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment
serialNumber, err := NextNumber(pkiroot, "serial")
if err != nil {
return fmt.Errorf("get next serial: %v", err)
}
template.SerialNumber = serialNumber
caCrt, caKey, err = GetCA(pkiroot)
if err != nil {
return fmt.Errorf("get ca: %v", err)
}
}
crt, err := x509.CreateCertificate(rand.Reader, template, caCrt, privateKey.Public(), caKey)
if err != nil {
return fmt.Errorf("create certificate: %v", err)
}
crtFile, err := os.Create(crtPath)
if err != nil {
return fmt.Errorf("create %v: %v", crtPath, err)
}
defer crtFile.Close()
err = pem.Encode(crtFile, &pem.Block{
Type: "CERTIFICATE",
Bytes: crt,
})
if err != nil {
return fmt.Errorf("pem encode crt: %v", err)
}
// I do not think we have to write the ca.crt in the index
if !template.IsCA {
WriteIndex(pkiroot, name, template)
if err != nil {
return fmt.Errorf("write index: %v", err)
}
}
return nil
}