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-rw-r--r--src/crypto/tls/generate_cert.go171
1 files changed, 171 insertions, 0 deletions
diff --git a/src/crypto/tls/generate_cert.go b/src/crypto/tls/generate_cert.go
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+++ b/src/crypto/tls/generate_cert.go
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+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build ignore
+
+// Generate a self-signed X.509 certificate for a TLS server. Outputs to
+// 'cert.pem' and 'key.pem' and will overwrite existing files.
+
+package main
+
+import (
+ "crypto/ecdsa"
+ "crypto/ed25519"
+ "crypto/elliptic"
+ "crypto/rand"
+ "crypto/rsa"
+ "crypto/x509"
+ "crypto/x509/pkix"
+ "encoding/pem"
+ "flag"
+ "log"
+ "math/big"
+ "net"
+ "os"
+ "strings"
+ "time"
+)
+
+var (
+ host = flag.String("host", "", "Comma-separated hostnames and IPs to generate a certificate for")
+ validFrom = flag.String("start-date", "", "Creation date formatted as Jan 1 15:04:05 2011")
+ validFor = flag.Duration("duration", 365*24*time.Hour, "Duration that certificate is valid for")
+ isCA = flag.Bool("ca", false, "whether this cert should be its own Certificate Authority")
+ rsaBits = flag.Int("rsa-bits", 2048, "Size of RSA key to generate. Ignored if --ecdsa-curve is set")
+ ecdsaCurve = flag.String("ecdsa-curve", "", "ECDSA curve to use to generate a key. Valid values are P224, P256 (recommended), P384, P521")
+ ed25519Key = flag.Bool("ed25519", false, "Generate an Ed25519 key")
+)
+
+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
+ }
+}
+
+func main() {
+ flag.Parse()
+
+ if len(*host) == 0 {
+ log.Fatalf("Missing required --host parameter")
+ }
+
+ var priv any
+ var err error
+ switch *ecdsaCurve {
+ case "":
+ if *ed25519Key {
+ _, priv, err = ed25519.GenerateKey(rand.Reader)
+ } else {
+ priv, err = rsa.GenerateKey(rand.Reader, *rsaBits)
+ }
+ case "P224":
+ priv, err = ecdsa.GenerateKey(elliptic.P224(), rand.Reader)
+ case "P256":
+ priv, err = ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+ case "P384":
+ priv, err = ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
+ case "P521":
+ priv, err = ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
+ default:
+ log.Fatalf("Unrecognized elliptic curve: %q", *ecdsaCurve)
+ }
+ if err != nil {
+ log.Fatalf("Failed to generate private key: %v", err)
+ }
+
+ // ECDSA, ED25519 and RSA subject keys should have the DigitalSignature
+ // KeyUsage bits set in the x509.Certificate template
+ keyUsage := x509.KeyUsageDigitalSignature
+ // Only RSA subject keys should have the KeyEncipherment KeyUsage bits set. In
+ // the context of TLS this KeyUsage is particular to RSA key exchange and
+ // authentication.
+ if _, isRSA := priv.(*rsa.PrivateKey); isRSA {
+ keyUsage |= x509.KeyUsageKeyEncipherment
+ }
+
+ var notBefore time.Time
+ if len(*validFrom) == 0 {
+ notBefore = time.Now()
+ } else {
+ notBefore, err = time.Parse("Jan 2 15:04:05 2006", *validFrom)
+ if err != nil {
+ log.Fatalf("Failed to parse creation date: %v", err)
+ }
+ }
+
+ notAfter := notBefore.Add(*validFor)
+
+ serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
+ serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
+ if err != nil {
+ log.Fatalf("Failed to generate serial number: %v", err)
+ }
+
+ template := x509.Certificate{
+ SerialNumber: serialNumber,
+ Subject: pkix.Name{
+ Organization: []string{"Acme Co"},
+ },
+ NotBefore: notBefore,
+ NotAfter: notAfter,
+
+ KeyUsage: keyUsage,
+ ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+ BasicConstraintsValid: true,
+ }
+
+ hosts := strings.Split(*host, ",")
+ for _, h := range hosts {
+ if ip := net.ParseIP(h); ip != nil {
+ template.IPAddresses = append(template.IPAddresses, ip)
+ } else {
+ template.DNSNames = append(template.DNSNames, h)
+ }
+ }
+
+ if *isCA {
+ template.IsCA = true
+ template.KeyUsage |= x509.KeyUsageCertSign
+ }
+
+ derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
+ if err != nil {
+ log.Fatalf("Failed to create certificate: %v", err)
+ }
+
+ certOut, err := os.Create("cert.pem")
+ if err != nil {
+ log.Fatalf("Failed to open cert.pem for writing: %v", err)
+ }
+ if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
+ log.Fatalf("Failed to write data to cert.pem: %v", err)
+ }
+ if err := certOut.Close(); err != nil {
+ log.Fatalf("Error closing cert.pem: %v", err)
+ }
+ log.Print("wrote cert.pem\n")
+
+ keyOut, err := os.OpenFile("key.pem", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+ if err != nil {
+ log.Fatalf("Failed to open key.pem for writing: %v", err)
+ }
+ privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
+ if err != nil {
+ log.Fatalf("Unable to marshal private key: %v", err)
+ }
+ if err := pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
+ log.Fatalf("Failed to write data to key.pem: %v", err)
+ }
+ if err := keyOut.Close(); err != nil {
+ log.Fatalf("Error closing key.pem: %v", err)
+ }
+ log.Print("wrote key.pem\n")
+}