138 lines
3.3 KiB
Go
138 lines
3.3 KiB
Go
package certs
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import (
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"crypto/ecdsa"
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"crypto/ed25519"
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"crypto/elliptic"
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"crypto/rand"
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"crypto/rsa"
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"crypto/tls"
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"crypto/x509"
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"crypto/x509/pkix"
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"encoding/pem"
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"log"
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"math/big"
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"net"
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"strings"
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"time"
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)
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// GenerateCertificate basic struct
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type GenerateCertificate struct {
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Organization string
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Host string
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ValidFrom string
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ValidFor time.Duration
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IsCA bool
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RSABits int
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EcdsaCurve string
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Ed25519Key bool
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}
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func (gc *GenerateCertificate) publicKey(priv interface{}) interface{} {
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switch k := priv.(type) {
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case *rsa.PrivateKey:
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return &k.PublicKey
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case *ecdsa.PrivateKey:
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return &k.PublicKey
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case ed25519.PrivateKey:
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return k.Public().(ed25519.PublicKey)
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default:
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return nil
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}
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}
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// GenerateTLSConfig create a TLS Config
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func (gc *GenerateCertificate) GenerateTLSConfig() (*tls.Config, error) {
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var priv interface{}
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var err error
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switch gc.EcdsaCurve {
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case "":
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if gc.Ed25519Key {
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_, priv, err = ed25519.GenerateKey(rand.Reader)
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} else {
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priv, err = rsa.GenerateKey(rand.Reader, gc.RSABits)
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}
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case "P224":
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priv, err = ecdsa.GenerateKey(elliptic.P224(), rand.Reader)
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case "P256":
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priv, err = ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
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case "P384":
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priv, err = ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
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case "P521":
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priv, err = ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
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default:
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log.Fatalf("Unrecognized elliptic curve: %q", gc.EcdsaCurve)
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return nil, err
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}
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if err != nil {
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log.Fatalf("Failed to generate private key: %v", err)
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return nil, err
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}
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var notBefore time.Time
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if len(gc.ValidFrom) == 0 {
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notBefore = time.Now()
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} else {
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notBefore, err = time.Parse("Jan 2 15:04:05 2006", gc.ValidFrom)
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if err != nil {
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log.Fatalf("Failed to parse creation date: %v", err)
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return nil, err
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}
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}
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notAfter := notBefore.Add(gc.ValidFor)
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serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
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serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
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if err != nil {
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log.Fatalf("Failed to generate serial number: %v", err)
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return nil, err
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}
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template := x509.Certificate{
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SerialNumber: serialNumber,
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Subject: pkix.Name{
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Organization: []string{gc.Organization},
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},
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NotBefore: notBefore,
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NotAfter: notAfter,
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KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
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ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
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BasicConstraintsValid: true,
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}
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hosts := strings.Split(gc.Host, ",")
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for _, h := range hosts {
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if ip := net.ParseIP(h); ip != nil {
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template.IPAddresses = append(template.IPAddresses, ip)
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} else {
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template.DNSNames = append(template.DNSNames, h)
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}
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}
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if gc.IsCA {
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template.IsCA = true
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template.KeyUsage |= x509.KeyUsageCertSign
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}
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derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, gc.publicKey(priv), priv)
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if err != nil {
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log.Fatalf("Failed to create certificate: %v", err)
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return nil, err
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}
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privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
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if err != nil {
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log.Fatalf("Unable to marshal private key: %v", err)
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return nil, err
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}
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keyPEM := pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: privBytes})
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certPEM := pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
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tlsCert, err := tls.X509KeyPair(certPEM, keyPEM)
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return &tls.Config{Certificates: []tls.Certificate{tlsCert}}, nil
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}
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