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 NewLANCert() (*tls.Certificate, error) { hosts, err := network.GetLANIPv4Addrs() if err != nil { return nil, errors.WithStack(err) } hosts = append(hosts, "127.0.0.1") rawCert, rawKey, err := NewCertKeyPair(hosts...) 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 } }