authentik/internal/crypto/generate.go

64 lines
1.7 KiB
Go

package crypto
import (
"crypto/rand"
"crypto/rsa"
"crypto/tls"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"math/big"
"time"
log "github.com/sirupsen/logrus"
)
// GenerateSelfSignedCert Generate a self-signed TLS Certificate, to be used as fallback
func GenerateSelfSignedCert() (tls.Certificate, error) {
priv, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
log.WithError(err).Warning("Failed to generate private key")
return tls.Certificate{}, err
}
keyUsage := x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment
notBefore := time.Now()
notAfter := notBefore.Add(365 * 24 * time.Hour)
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
log.WithError(err).Warning("Failed to generate serial number")
return tls.Certificate{}, err
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Organization: []string{"authentik"},
CommonName: "authentik default certificate",
},
NotBefore: notBefore,
NotAfter: notAfter,
KeyUsage: keyUsage,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
}
template.DNSNames = []string{"*"}
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
if err != nil {
log.Warning(err)
}
pemBytes := pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
if err != nil {
log.Warning(err)
}
privPemByes := pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: privBytes})
return tls.X509KeyPair(pemBytes, privPemByes)
}