traefik/tls/generate/generate.go

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package generate
import (
"crypto/rand"
"crypto/rsa"
"crypto/sha256"
"crypto/tls"
"crypto/x509"
"crypto/x509/pkix"
"encoding/hex"
"encoding/pem"
"fmt"
"math/big"
"time"
)
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// DefaultDomain Traefik domain for the default certificate
const DefaultDomain = "TRAEFIK DEFAULT CERT"
// DefaultCertificate generates random TLS certificates
func DefaultCertificate() (*tls.Certificate, error) {
randomBytes := make([]byte, 100)
_, err := rand.Read(randomBytes)
if err != nil {
return nil, err
}
zBytes := sha256.Sum256(randomBytes)
z := hex.EncodeToString(zBytes[:sha256.Size])
domain := fmt.Sprintf("%s.%s.traefik.default", z[:32], z[32:])
certPEM, keyPEM, err := KeyPair(domain, time.Time{})
if err != nil {
return nil, err
}
certificate, err := tls.X509KeyPair(certPEM, keyPEM)
if err != nil {
return nil, err
}
return &certificate, nil
}
// KeyPair generates cert and key files
func KeyPair(domain string, expiration time.Time) ([]byte, []byte, error) {
rsaPrivKey, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
return nil, nil, err
}
keyPEM := pem.EncodeToMemory(&pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(rsaPrivKey)})
certPEM, err := PemCert(rsaPrivKey, domain, expiration)
if err != nil {
return nil, nil, err
}
return certPEM, keyPEM, nil
}
// PemCert generates PEM cert file
func PemCert(privKey *rsa.PrivateKey, domain string, expiration time.Time) ([]byte, error) {
derBytes, err := derCert(privKey, expiration, domain)
if err != nil {
return nil, err
}
return pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes}), nil
}
func derCert(privKey *rsa.PrivateKey, expiration time.Time, domain string) ([]byte, error) {
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
return nil, err
}
if expiration.IsZero() {
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expiration = time.Now().Add(365 * (24 * time.Hour))
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
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CommonName: DefaultDomain,
},
NotBefore: time.Now(),
NotAfter: expiration,
KeyUsage: x509.KeyUsageKeyEncipherment,
BasicConstraintsValid: true,
DNSNames: []string{domain},
}
return x509.CreateCertificate(rand.Reader, &template, &template, &privKey.PublicKey, privKey)
}