arcast/pkg/selfsigned/cert.go

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package selfsigned
import (
"bytes"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/elliptic"
"crypto/rand"
"crypto/rsa"
"crypto/tls"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"math/big"
"net"
"time"
"forge.cadoles.com/arcad/arcast/pkg/network"
"github.com/pkg/errors"
)
func NewLANKeyPair() ([]byte, []byte, error) {
hosts, err := network.GetLANIPv4Addrs()
if err != nil {
return nil, nil, errors.WithStack(err)
}
hosts = append(hosts, "127.0.0.1")
rawCert, rawKey, err := NewCertKeyPair(hosts...)
if err != nil {
return nil, nil, errors.WithStack(err)
}
return rawCert, rawKey, nil
}
func NewLANCert() (*tls.Certificate, error) {
rawCert, rawKey, err := NewLANKeyPair()
if err != nil {
return nil, errors.WithStack(err)
}
cert, err := tls.X509KeyPair(rawCert, rawKey)
if err != nil {
return nil, errors.WithStack(err)
}
return &cert, nil
}
func NewCertKeyPair(hosts ...string) ([]byte, []byte, error) {
priv, err := ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
if err != nil {
return nil, nil, errors.WithStack(err)
}
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
return nil, nil, errors.WithStack(err)
}
keyUsage := x509.KeyUsageDigitalSignature
notBefore := time.Now()
notAfter := notBefore.Add(365 * 24 * time.Hour)
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Organization: []string{"Arcast Org"},
},
NotBefore: notBefore,
NotAfter: notAfter,
KeyUsage: keyUsage,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
}
for _, h := range hosts {
if ip := net.ParseIP(h); ip != nil {
template.IPAddresses = append(template.IPAddresses, ip)
} else {
template.DNSNames = append(template.DNSNames, h)
}
}
template.IsCA = true
template.KeyUsage |= x509.KeyUsageCertSign
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
if err != nil {
return nil, nil, errors.WithStack(err)
}
var cert bytes.Buffer
if err := pem.Encode(&cert, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
return nil, nil, errors.WithStack(err)
}
var key bytes.Buffer
privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
if err != nil {
return nil, nil, errors.WithStack(err)
}
if err := pem.Encode(&key, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
return nil, nil, errors.WithStack(err)
}
return cert.Bytes(), key.Bytes(), nil
}
func publicKey(priv any) any {
switch k := priv.(type) {
case *rsa.PrivateKey:
return &k.PublicKey
case *ecdsa.PrivateKey:
return &k.PublicKey
case ed25519.PrivateKey:
return k.Public().(ed25519.PublicKey)
default:
return nil
}
}