1 files changed, 196 insertions, 0 deletions
diff --git a/cmd/cert.go b/cmd/cert.go
new file mode 100644
index 00000000..bf83af38
--- /dev/null
+++ b/cmd/cert.go
@@ -0,0 +1,196 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Copyright 2014 The Gogs Authors. All rights reserved.
+// Copyright 2016 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cmd
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"log"
+	"math/big"
+	"net"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/urfave/cli/v2"
+)
+
+// CmdCert represents the available cert sub-command.
+var CmdCert = &cli.Command{
+	Name:  "cert",
+	Usage: "Generate self-signed certificate",
+	Description: `Generate a self-signed X.509 certificate for a TLS server.
+Outputs to 'cert.pem' and 'key.pem' and will overwrite existing files.`,
+	Action: runCert,
+	Flags: []cli.Flag{
+		&cli.StringFlag{
+			Name:  "host",
+			Value: "",
+			Usage: "Comma-separated hostnames and IPs to generate a certificate for",
+		},
+		&cli.StringFlag{
+			Name:  "ecdsa-curve",
+			Value: "",
+			Usage: "ECDSA curve to use to generate a key. Valid values are P224, P256, P384, P521",
+		},
+		&cli.IntFlag{
+			Name:  "rsa-bits",
+			Value: 3072,
+			Usage: "Size of RSA key to generate. Ignored if --ecdsa-curve is set",
+		},
+		&cli.StringFlag{
+			Name:  "start-date",
+			Value: "",
+			Usage: "Creation date formatted as Jan 1 15:04:05 2011",
+		},
+		&cli.DurationFlag{
+			Name:  "duration",
+			Value: 365 * 24 * time.Hour,
+			Usage: "Duration that certificate is valid for",
+		},
+		&cli.BoolFlag{
+			Name:  "ca",
+			Usage: "whether this cert should be its own Certificate Authority",
+		},
+	},
+}
+
+func publicKey(priv any) any {
+	switch k := priv.(type) {
+	case *rsa.PrivateKey:
+		return &k.PublicKey
+	case *ecdsa.PrivateKey:
+		return &k.PublicKey
+	default:
+		return nil
+	}
+}
+
+func pemBlockForKey(priv any) *pem.Block {
+	switch k := priv.(type) {
+	case *rsa.PrivateKey:
+		return &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(k)}
+	case *ecdsa.PrivateKey:
+		b, err := x509.MarshalECPrivateKey(k)
+		if err != nil {
+			log.Fatalf("Unable to marshal ECDSA private key: %v", err)
+		}
+		return &pem.Block{Type: "EC PRIVATE KEY", Bytes: b}
+	default:
+		return nil
+	}
+}
+
+func runCert(c *cli.Context) error {
+	if err := argsSet(c, "host"); err != nil {
+		return err
+	}
+
+	var priv any
+	var err error
+	switch c.String("ecdsa-curve") {
+	case "":
+		priv, err = rsa.GenerateKey(rand.Reader, c.Int("rsa-bits"))
+	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", c.String("ecdsa-curve"))
+	}
+	if err != nil {
+		log.Fatalf("Failed to generate private key: %v", err)
+	}
+
+	var notBefore time.Time
+	if startDate := c.String("start-date"); startDate != "" {
+		notBefore, err = time.Parse("Jan 2 15:04:05 2006", startDate)
+		if err != nil {
+			log.Fatalf("Failed to parse creation date: %v", err)
+		}
+	} else {
+		notBefore = time.Now()
+	}
+
+	notAfter := notBefore.Add(c.Duration("duration"))
+
+	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"},
+			CommonName:   "Forgejo",
+		},
+		NotBefore: notBefore,
+		NotAfter:  notAfter,
+
+		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+		BasicConstraintsValid: true,
+	}
+
+	hosts := strings.Split(c.String("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 c.Bool("ca") {
+		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)
+	}
+	err = pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
+	if err != nil {
+		log.Fatalf("Failed to encode certificate: %v", err)
+	}
+	err = certOut.Close()
+	if err != nil {
+		log.Fatalf("Failed to write cert: %v", err)
+	}
+	log.Println("Written cert.pem")
+
+	keyOut, err := os.OpenFile("key.pem", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0o600)
+	if err != nil {
+		log.Fatalf("Failed to open key.pem for writing: %v", err)
+	}
+	err = pem.Encode(keyOut, pemBlockForKey(priv))
+	if err != nil {
+		log.Fatalf("Failed to encode key: %v", err)
+	}
+	err = keyOut.Close()
+	if err != nil {
+		log.Fatalf("Failed to write key: %v", err)
+	}
+	log.Println("Written key.pem")
+	return nil
+}