98 lines
2.7 KiB
Go
98 lines
2.7 KiB
Go
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package certificates
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import (
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"crypto/rand"
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"crypto/rsa"
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"crypto/x509"
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"crypto/x509/pkix"
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"encoding/pem"
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"fmt"
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"math/big"
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"net"
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"os"
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"strings"
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"time"
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)
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func GenerateKeyPair(host string) (*rsa.PrivateKey, []byte, error) {
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priv, err := rsa.GenerateKey(rand.Reader, 2048)
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if err != nil {
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return &rsa.PrivateKey{}, []byte{}, err
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}
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keyUsage := x509.KeyUsageDigitalSignature
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notBefore := time.Now()
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notAfter := notBefore.Add(time.Hour * 24 * 365 * 5) // five yearss
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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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return &rsa.PrivateKey{}, []byte{}, 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{"Castor Server"},
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},
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NotBefore: notBefore,
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NotAfter: notAfter,
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KeyUsage: keyUsage,
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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(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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bytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
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if err != nil {
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return &rsa.PrivateKey{}, []byte{}, err
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}
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return priv, bytes, nil
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}
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func TestCertificateExists(certname, keyname string) error {
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_, err := os.Stat(certname)
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if err != nil {
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return fmt.Errorf("Could not open %s; %w", certname, err)
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}
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_, err = os.Stat(keyname)
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if err != nil {
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return fmt.Errorf("Could not open %s; %w", keyname, err)
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}
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return nil
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}
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func WriteCertsToFile(certname, keyname string, cert []byte, privkey *rsa.PrivateKey) error {
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certOut, err := os.Create(certname)
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if err != nil {
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return fmt.Errorf("Failed to open %s for writing: %w", certname, err)
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}
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if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: cert}); err != nil {
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return fmt.Errorf("Failed to write data to %s: %w", certname, err)
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}
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if err := certOut.Close(); err != nil {
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return fmt.Errorf("Error closing %s: %w", certname, err)
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}
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keyOut, err := os.OpenFile(keyname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
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if err != nil {
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return fmt.Errorf("Failed to open %s for writing: %w", keyname, err)
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}
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privBytes, err := x509.MarshalPKCS8PrivateKey(privkey)
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if err != nil {
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return fmt.Errorf("Unable to marshal private key: %v", err)
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}
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if err := pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
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return fmt.Errorf("Failed to write data to %s: %v", keyname, err)
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}
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if err := keyOut.Close(); err != nil {
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return fmt.Errorf("Error closing %s: %v", keyname, err)
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}
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return nil
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}
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