func (crtkit *CertKit) GenerateServer(subject pkix.Name, host, email string, NotBefore ...time.Time) error {
var e error
var derBytes []byte
var notBefore time.Time
priv, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
return errors.New(fmt.Sprintf("failed to generate private key: %s", err))
}
if len(NotBefore) > 0 {
notBefore = NotBefore[0]
} else {
notBefore = time.Now()
}
serialNumber, err := rand.Int(rand.Reader, new(big.Int).Lsh(big.NewInt(1), 128))
if err != nil {
return errors.New(fmt.Sprintf("failed to generate serial number: %s", err))
}
if host == "" {
host, _ = os.Hostname()
}
Goose.Generator.Logf(6, "Certificate authority used: %#v", crtkit.CACert)
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: subject,
IsCA: false,
NotBefore: notBefore,
NotAfter: notBefore.Add(365 * 24 * time.Hour),
DNSNames: []string{host, strings.Split(host, ".")[0]},
AuthorityKeyId: crtkit.CACert.SubjectKeyId,
KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageContentCommitment,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageClientAuth},
BasicConstraintsValid: true,
}
Goose.Generator.Logf(4, "X509 Template: %#v", template)
if crtkit.CACert.CRLDistributionPoints != nil {
template.CRLDistributionPoints = crtkit.CACert.CRLDistributionPoints
} else {
Goose.Generator.Logf(1, "Certificate authority without CRL distribution points")
}
crtkit.ServerKey = priv
crtkit.ServerCert = &template
derBytes, e = x509.CreateCertificate(rand.Reader, &template, crtkit.CACert, &priv.PublicKey, crtkit.CAKey)
if e != nil {
return errors.New(fmt.Sprintf("Failed to create certificate: %s", e))
}
Goose.Generator.Logf(4, "DER Certificate: %s", derBytes)
crtkit.ServerCertPem = pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
crtkit.ServerKeyPem = pem.EncodeToMemory(&pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(priv)})
Goose.Generator.Logf(4, "PEM Certificate: %s", crtkit.ServerCertPem)
return nil
}
func (s *Signer) sign(template *x509.Certificate, profile *config.SigningProfile) (cert []byte, err error) {
var distPoints = template.CRLDistributionPoints
err = signer.FillTemplate(template, s.policy.Default, profile)
if distPoints != nil && len(distPoints) > 0 {
template.CRLDistributionPoints = distPoints
}
if err != nil {
return
}
var initRoot bool
if s.ca == nil {
if !template.IsCA {
err = cferr.New(cferr.PolicyError, cferr.InvalidRequest)
return
}
template.DNSNames = nil
template.EmailAddresses = nil
s.ca = template
initRoot = true
} else if template.IsCA {
template.DNSNames = nil
template.EmailAddresses = nil
}
derBytes, err := x509.CreateCertificate(rand.Reader, template, s.ca, template.PublicKey, s.priv)
if err != nil {
return nil, cferr.Wrap(cferr.CertificateError, cferr.Unknown, err)
}
if initRoot {
s.ca, err = x509.ParseCertificate(derBytes)
if err != nil {
return nil, cferr.Wrap(cferr.CertificateError, cferr.ParseFailed, err)
}
}
cert = pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
log.Infof("signed certificate with serial number %d", template.SerialNumber)
return
}
// FillTemplate is a utility function that tries to load as much of
// the certificate template as possible from the profiles and current
// template. It fills in the key uses, expiration, revocation URLs
// and SKI.
func FillTemplate(template *x509.Certificate, defaultProfile, profile *config.SigningProfile) error {
ski, err := ComputeSKI(template)
var (
eku []x509.ExtKeyUsage
ku x509.KeyUsage
backdate time.Duration
expiry time.Duration
notBefore time.Time
notAfter time.Time
crlURL, ocspURL string
)
// The third value returned from Usages is a list of unknown key usages.
// This should be used when validating the profile at load, and isn't used
// here.
ku, eku, _ = profile.Usages()
if profile.IssuerURL == nil {
profile.IssuerURL = defaultProfile.IssuerURL
}
if ku == 0 && len(eku) == 0 {
return cferr.New(cferr.PolicyError, cferr.NoKeyUsages)
}
if expiry = profile.Expiry; expiry == 0 {
expiry = defaultProfile.Expiry
}
if crlURL = profile.CRL; crlURL == "" {
crlURL = defaultProfile.CRL
}
if ocspURL = profile.OCSP; ocspURL == "" {
ocspURL = defaultProfile.OCSP
}
if backdate = profile.Backdate; backdate == 0 {
backdate = -5 * time.Minute
} else {
backdate = -1 * profile.Backdate
}
if !profile.NotBefore.IsZero() {
notBefore = profile.NotBefore.UTC()
} else {
notBefore = time.Now().Round(time.Minute).Add(backdate).UTC()
}
if !profile.NotAfter.IsZero() {
notAfter = profile.NotAfter.UTC()
} else {
notAfter = notBefore.Add(expiry).UTC()
}
template.NotBefore = notBefore
template.NotAfter = notAfter
template.KeyUsage = ku
template.ExtKeyUsage = eku
template.BasicConstraintsValid = true
template.IsCA = profile.CA
template.SubjectKeyId = ski
if ocspURL != "" {
template.OCSPServer = []string{ocspURL}
}
if crlURL != "" {
template.CRLDistributionPoints = []string{crlURL}
}
if len(profile.IssuerURL) != 0 {
template.IssuingCertificateURL = profile.IssuerURL
}
if len(profile.Policies) != 0 {
err = addPolicies(template, profile.Policies)
if err != nil {
return cferr.Wrap(cferr.PolicyError, cferr.InvalidPolicy, err)
}
}
if profile.OCSPNoCheck {
ocspNoCheckExtension := pkix.Extension{
Id: asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 48, 1, 5},
Critical: false,
Value: []byte{0x05, 0x00},
}
template.ExtraExtensions = append(template.ExtraExtensions, ocspNoCheckExtension)
}
return nil
}
func (s *Signer) sign(template *x509.Certificate, profile *config.SigningProfile) (cert []byte, err error) {
pub := template.PublicKey
encodedpub, err := x509.MarshalPKIXPublicKey(pub)
if err != nil {
return
}
pubhash := sha1.New()
pubhash.Write(encodedpub)
if profile == nil {
profile = s.Policy.Default
}
var (
eku []x509.ExtKeyUsage
ku x509.KeyUsage
expiry time.Duration
crlURL, ocspURL string
)
// The third value returned from Usages is a list of unknown key usages.
// This should be used when validating the profile at load, and isn't used
// here.
ku, eku, _ = profile.Usages()
expiry = profile.Expiry
if profile.IssuerURL == nil {
profile.IssuerURL = s.Policy.Default.IssuerURL
}
if ku == 0 && len(eku) == 0 {
err = cferr.New(cferr.PolicyError, cferr.NoKeyUsages, errors.New("no key usage available"))
return
}
if expiry == 0 {
expiry = s.Policy.Default.Expiry
}
if crlURL = profile.CRL; crlURL == "" {
crlURL = s.Policy.Default.CRL
}
if ocspURL = profile.OCSP; ocspURL == "" {
ocspURL = s.Policy.Default.OCSP
}
now := time.Now()
serialNumber, err := rand.Int(rand.Reader, new(big.Int).SetInt64(math.MaxInt64))
if err != nil {
err = cferr.New(cferr.CertificateError, cferr.Unknown, err)
}
template.SerialNumber = serialNumber
template.NotBefore = now.Add(-5 * time.Minute).UTC()
template.NotAfter = now.Add(expiry).UTC()
template.KeyUsage = ku
template.ExtKeyUsage = eku
template.BasicConstraintsValid = true
template.IsCA = profile.CA
template.SubjectKeyId = pubhash.Sum(nil)
if ocspURL != "" {
template.OCSPServer = []string{ocspURL}
}
if crlURL != "" {
template.CRLDistributionPoints = []string{crlURL}
}
if len(profile.IssuerURL) != 0 {
template.IssuingCertificateURL = profile.IssuerURL
}
var initRoot bool
if s.CA == nil {
if !template.IsCA {
err = cferr.New(cferr.PolicyError, cferr.InvalidRequest, nil)
return
}
template.DNSNames = nil
s.CA = template
initRoot = true
template.MaxPathLen = 2
} else if template.IsCA {
template.MaxPathLen = 1
template.DNSNames = nil
}
derBytes, err := x509.CreateCertificate(rand.Reader, template, s.CA, pub, s.Priv)
if err != nil {
return
}
if initRoot {
s.CA, err = x509.ParseCertificate(derBytes)
if err != nil {
err = cferr.New(cferr.CertificateError, cferr.ParseFailed, err)
return
}
}
cert = pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
return
}
// Sign signs a new certificate based on the PEM-encoded client
// certificate or certificate request with the signing profile,
// specified by profileName.
func (s *Signer) Sign(req signer.SignRequest) (cert []byte, err error) {
profile, err := signer.Profile(s, req.Profile)
if err != nil {
return
}
block, _ := pem.Decode([]byte(req.Request))
if block == nil {
return nil, cferr.New(cferr.CSRError, cferr.DecodeFailed)
}
if block.Type != "NEW CERTIFICATE REQUEST" && block.Type != "CERTIFICATE REQUEST" {
return nil, cferr.Wrap(cferr.CSRError,
cferr.BadRequest, errors.New("not a certificate or csr"))
}
csrTemplate, err := signer.ParseCertificateRequest(s, block.Bytes)
if err != nil {
return nil, err
}
// Copy out only the fields from the CSR authorized by policy.
safeTemplate := x509.Certificate{}
// If the profile contains no explicit whitelist, assume that all fields
// should be copied from the CSR.
if profile.CSRWhitelist == nil {
safeTemplate = *csrTemplate
} else {
if profile.CSRWhitelist.Subject {
safeTemplate.Subject = csrTemplate.Subject
}
if profile.CSRWhitelist.PublicKeyAlgorithm {
safeTemplate.PublicKeyAlgorithm = csrTemplate.PublicKeyAlgorithm
}
if profile.CSRWhitelist.PublicKey {
safeTemplate.PublicKey = csrTemplate.PublicKey
}
if profile.CSRWhitelist.SignatureAlgorithm {
safeTemplate.SignatureAlgorithm = csrTemplate.SignatureAlgorithm
}
if profile.CSRWhitelist.DNSNames {
safeTemplate.DNSNames = csrTemplate.DNSNames
}
if profile.CSRWhitelist.IPAddresses {
safeTemplate.IPAddresses = csrTemplate.IPAddresses
}
if profile.CSRWhitelist.EmailAddresses {
safeTemplate.EmailAddresses = csrTemplate.EmailAddresses
}
}
if req.CRLOverride != "" {
safeTemplate.CRLDistributionPoints = []string{req.CRLOverride}
}
if safeTemplate.IsCA {
if !profile.CA {
return nil, cferr.New(cferr.CertificateError, cferr.InvalidRequest)
}
if s.ca != nil && s.ca.MaxPathLen > 0 {
if safeTemplate.MaxPathLen >= s.ca.MaxPathLen {
// do not sign a cert with pathlen > current
return nil, cferr.New(cferr.CertificateError, cferr.InvalidRequest)
}
} else if s.ca != nil && s.ca.MaxPathLen == 0 && s.ca.MaxPathLenZero {
// signer has pathlen of 0, do not sign more intermediate CAs
return nil, cferr.New(cferr.CertificateError, cferr.InvalidRequest)
}
}
OverrideHosts(&safeTemplate, req.Hosts)
safeTemplate.Subject = PopulateSubjectFromCSR(req.Subject, safeTemplate.Subject)
// If there is a whitelist, ensure that both the Common Name and SAN DNSNames match
if profile.NameWhitelist != nil {
if safeTemplate.Subject.CommonName != "" {
if profile.NameWhitelist.Find([]byte(safeTemplate.Subject.CommonName)) == nil {
return nil, cferr.New(cferr.PolicyError, cferr.InvalidPolicy)
}
}
for _, name := range safeTemplate.DNSNames {
if profile.NameWhitelist.Find([]byte(name)) == nil {
return nil, cferr.New(cferr.PolicyError, cferr.InvalidPolicy)
}
}
for _, name := range safeTemplate.EmailAddresses {
if profile.NameWhitelist.Find([]byte(name)) == nil {
return nil, cferr.New(cferr.PolicyError, cferr.InvalidPolicy)
}
}
}
if profile.ClientProvidesSerialNumbers {
if req.Serial == nil {
return nil, cferr.New(cferr.CertificateError, cferr.MissingSerial)
}
safeTemplate.SerialNumber = req.Serial
} else {
// RFC 5280 4.1.2.2:
// Certificate users MUST be able to handle serialNumber
// values up to 20 octets. Conforming CAs MUST NOT use
// serialNumber values longer than 20 octets.
//
// If CFSSL is providing the serial numbers, it makes
// sense to use the max supported size.
serialNumber := make([]byte, 20)
_, err = io.ReadFull(rand.Reader, serialNumber)
if err != nil {
return nil, cferr.Wrap(cferr.CertificateError, cferr.Unknown, err)
}
// SetBytes interprets buf as the bytes of a big-endian
// unsigned integer. The leading byte should be masked
// off to ensure it isn't negative.
serialNumber[0] &= 0x7F
safeTemplate.SerialNumber = new(big.Int).SetBytes(serialNumber)
}
if len(req.Extensions) > 0 {
for _, ext := range req.Extensions {
oid := asn1.ObjectIdentifier(ext.ID)
if !profile.ExtensionWhitelist[oid.String()] {
return nil, cferr.New(cferr.CertificateError, cferr.InvalidRequest)
}
rawValue, err := hex.DecodeString(ext.Value)
if err != nil {
return nil, cferr.Wrap(cferr.CertificateError, cferr.InvalidRequest, err)
}
safeTemplate.ExtraExtensions = append(safeTemplate.ExtraExtensions, pkix.Extension{
Id: oid,
Critical: ext.Critical,
Value: rawValue,
})
}
}
var certTBS = safeTemplate
if len(profile.CTLogServers) > 0 {
// Add a poison extension which prevents validation
var poisonExtension = pkix.Extension{Id: signer.CTPoisonOID, Critical: true, Value: []byte{0x05, 0x00}}
var poisonedPreCert = certTBS
poisonedPreCert.ExtraExtensions = append(safeTemplate.ExtraExtensions, poisonExtension)
cert, err = s.sign(&poisonedPreCert, profile)
if err != nil {
return
}
derCert, _ := pem.Decode(cert)
prechain := []ct.ASN1Cert{derCert.Bytes, s.ca.Raw}
var sctList []ct.SignedCertificateTimestamp
for _, server := range profile.CTLogServers {
log.Infof("submitting poisoned precertificate to %s", server)
var ctclient = client.New(server)
var resp *ct.SignedCertificateTimestamp
resp, err = ctclient.AddPreChain(prechain)
if err != nil {
return nil, cferr.Wrap(cferr.CTError, cferr.PrecertSubmissionFailed, err)
}
sctList = append(sctList, *resp)
}
var serializedSCTList []byte
serializedSCTList, err = serializeSCTList(sctList)
if err != nil {
return nil, cferr.Wrap(cferr.CTError, cferr.Unknown, err)
}
// Serialize again as an octet string before embedding
serializedSCTList, err = asn1.Marshal(serializedSCTList)
if err != nil {
return nil, cferr.Wrap(cferr.CTError, cferr.Unknown, err)
}
var SCTListExtension = pkix.Extension{Id: signer.SCTListOID, Critical: false, Value: serializedSCTList}
certTBS.ExtraExtensions = append(certTBS.ExtraExtensions, SCTListExtension)
}
var signedCert []byte
signedCert, err = s.sign(&certTBS, profile)
if err != nil {
return nil, err
}
if s.dbAccessor != nil {
var certRecord = certdb.CertificateRecord{
Serial: certTBS.SerialNumber.String(),
// this relies on the specific behavior of x509.CreateCertificate
// which updates certTBS AuthorityKeyId from the signer's SubjectKeyId
AKI: hex.EncodeToString(certTBS.AuthorityKeyId),
CALabel: req.Label,
Status: "good",
Expiry: certTBS.NotAfter,
PEM: string(signedCert),
}
err = s.dbAccessor.InsertCertificate(certRecord)
if err != nil {
return nil, err
}
log.Debug("saved certificate with serial number ", certTBS.SerialNumber)
}
return signedCert, nil
}