lourenco/mgmt
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

util: Add a TLS helper

Browse Source 
Make it easier to build TLS stuff in pure golang.
This commit is contained in:
James Shubin
2024-11-01 19:41:35 -04:00
parent e4f062b006
commit 3fb492f6aa
2 changed files with 227 additions and 169 deletions
Download Patch File Download Diff File Expand all files Collapse all files

172
examples/tls/tls.go
View File

@@ -3,166 +3,13 @@
package main
import (
"crypto/ecdsa"
"crypto/ed25519"
"crypto/elliptic"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"fmt"
"log"
"math/big"
"net"
"net/http"
"os"
"strings"
"time"
"github.com/purpleidea/mgmt/util"
)
// NewTLS builds a new TLS struct with some defaults.
func NewTLS() *TLS {
return &TLS{
ValidFor: 365 * 24 * time.Hour,
RsaBits: 2048,
}
}
// TLS handles all of the TLS building.
type TLS struct {
Host string // Comma-separated hostnames and IPs to generate a certificate for
ValidFrom string // Creation date formatted as Jan 1 15:04:05 2011
ValidFor time.Duration // Duration that certificate is valid for
IsCA bool // Whether this cert should be its own Certificate Authority
RsaBits int // Size of RSA key to generate. Ignored if EcdsaCurve is set
EcdsaCurve string // ECDSA curve to use to generate a key. Valid values are P224, P256 (recommended), P384, P521
Ed25519Key bool // Generate an Ed25519 key
}
// Generate writes out the two files. Usually keyPemFile is key.pem and
// certPemFile is cert.pem which go into http.ListenAndServeTLS.
func (obj *TLS) Generate(keyPemFile, certPemFile string) error {
if len(obj.Host) == 0 {
return fmt.Errorf("missing required Host parameter")
}
var priv any
var err error
switch obj.EcdsaCurve {
case "":
if obj.Ed25519Key {
_, priv, err = ed25519.GenerateKey(rand.Reader)
} else {
priv, err = rsa.GenerateKey(rand.Reader, obj.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:
return fmt.Errorf("unrecognized elliptic curve: %q", obj.EcdsaCurve)
}
if err != nil {
return fmt.Errorf("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(obj.ValidFrom) == 0 {
notBefore = time.Now()
} else {
notBefore, err = time.Parse("Jan 2 15:04:05 2006", obj.ValidFrom)
if err != nil {
return fmt.Errorf("failed to parse creation date: %v", err)
}
}
notAfter := notBefore.Add(obj.ValidFor)
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
return fmt.Errorf("failed to generate serial number: %v", err)
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Organization: []string{"Whatever Corp"}, // XXX: change me...
},
NotBefore: notBefore,
NotAfter: notAfter,
KeyUsage: keyUsage,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
}
hosts := strings.Split(obj.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 obj.IsCA {
template.IsCA = true
template.KeyUsage |= x509.KeyUsageCertSign
}
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
if err != nil {
return fmt.Errorf("failed to create certificate: %v", err)
}
certOut, err := os.Create(certPemFile)
if err != nil {
return fmt.Errorf("failed to open %s for writing: %v", certPemFile, err)
}
if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
return fmt.Errorf("failed to write data to %s: %v", certPemFile, err)
}
if err := certOut.Close(); err != nil {
return fmt.Errorf("error closing %s: %v", certPemFile, err)
}
log.Printf("wrote %s", certPemFile)
keyOut, err := os.OpenFile(keyPemFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
return fmt.Errorf("failed to open %s for writing: %v", keyPemFile, err)
}
privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
if err != nil {
return fmt.Errorf("unable to marshal private key: %v", err)
}
if err := pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
return fmt.Errorf("failed to write data to %s: %v", keyPemFile, err)
}
if err := keyOut.Close(); err != nil {
return fmt.Errorf("error closing %s: %v", keyPemFile, err)
}
log.Printf("wrote %s", keyPemFile)
return nil
}
// HelloServer is a simple handler.
func HelloServer(w http.ResponseWriter, req *http.Request) {
fmt.Printf("req: %+v\n", req)
@@ -170,23 +17,10 @@ func HelloServer(w http.ResponseWriter, req *http.Request) {
w.Write([]byte("This is hello world!\n"))
}
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() {
// wget --no-check-certificate https://127.0.0.1:1443/hello -O -
tls := NewTLS()
tls := util.NewTLS()
tls.Host = "localhost" // TODO: choose something
keyPemFile := "/tmp/key.pem"
certPemFile := "/tmp/cert.pem"

224
util/tls.go Normal file
View File

@@ -0,0 +1,224 @@
// Mgmt
// Copyright (C) 2013-2024+ James Shubin and the project contributors
// Written by James Shubin <james@shubin.ca> and the project contributors
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
//
// Additional permission under GNU GPL version 3 section 7
//
// If you modify this program, or any covered work, by linking or combining it
// with embedded mcl code and modules (and that the embedded mcl code and
// modules which link with this program, contain a copy of their source code in
// the authoritative form) containing parts covered by the terms of any other
// license, the licensors of this program grant you additional permission to
// convey the resulting work. Furthermore, the licensors of this program grant
// the original author, James Shubin, additional permission to update this
// additional permission if he deems it necessary to achieve the goals of this
// additional permission.
// Modified from: golang/src/crypto/tls/generate_cert.go
package util
import (
"crypto/ecdsa"
"crypto/ed25519"
"crypto/elliptic"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"fmt"
"log"
"math/big"
"net"
"os"
"strings"
"time"
)
// NewTLS builds a new TLS struct with some defaults.
func NewTLS() *TLS {
return &TLS{
ValidFor: 365 * 24 * time.Hour,
RsaBits: 2048,
Organization: "Example Corp",
}
}
// TLS handles all of the TLS building.
type TLS struct {
// Host is comma-separated hostnames and IPs to generate a certificate
// for.
Host string
// ValidFrom is the creation date formatted as Jan 1 15:04:05 2011.
ValidFrom string
// ValidFor is the duration that certificate is valid for.
ValidFor time.Duration
// IsCA is Whether this cert should be its own Certificate Authority.
IsCA bool
// RsaBits is the size of RSA key to generate. Ignored if EcdsaCurve is
// set.
RsaBits int
// EcdsaCurve is the ECDSA curve to use to generate a key. Valid values
// are P224, P256 (recommended), P384, P521.
EcdsaCurve string
// Ed25519Key is true to generate an Ed25519 key.
Ed25519Key bool
// Organization is the name of the organization to store in the cert.
Organization string
}
// Generate writes out the two files. Usually keyPemFile is key.pem and
// certPemFile is cert.pem which go into http.ListenAndServeTLS.
func (obj *TLS) Generate(keyPemFile, certPemFile string) error {
if len(obj.Host) == 0 {
return fmt.Errorf("missing required Host parameter")
}
var priv any
var err error
switch obj.EcdsaCurve {
case "":
if obj.Ed25519Key {
_, priv, err = ed25519.GenerateKey(rand.Reader)
} else {
priv, err = rsa.GenerateKey(rand.Reader, obj.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:
return fmt.Errorf("unrecognized elliptic curve: %q", obj.EcdsaCurve)
}
if err != nil {
return fmt.Errorf("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(obj.ValidFrom) == 0 {
notBefore = time.Now()
} else {
notBefore, err = time.Parse("Jan 2 15:04:05 2006", obj.ValidFrom)
if err != nil {
return fmt.Errorf("failed to parse creation date: %v", err)
}
}
notAfter := notBefore.Add(obj.ValidFor)
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
return fmt.Errorf("failed to generate serial number: %v", err)
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Organization: []string{obj.Organization},
},
NotBefore: notBefore,
NotAfter: notAfter,
KeyUsage: keyUsage,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
}
hosts := strings.Split(obj.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 obj.IsCA {
template.IsCA = true
template.KeyUsage |= x509.KeyUsageCertSign
}
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, obj.publicKey(priv), priv)
if err != nil {
return fmt.Errorf("failed to create certificate: %v", err)
}
certOut, err := os.Create(certPemFile)
if err != nil {
return fmt.Errorf("failed to open %s for writing: %v", certPemFile, err)
}
if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
return fmt.Errorf("failed to write data to %s: %v", certPemFile, err)
}
if err := certOut.Close(); err != nil {
return fmt.Errorf("error closing %s: %v", certPemFile, err)
}
log.Printf("wrote %s", certPemFile)
keyOut, err := os.OpenFile(keyPemFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
return fmt.Errorf("failed to open %s for writing: %v", keyPemFile, err)
}
privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
if err != nil {
return fmt.Errorf("unable to marshal private key: %v", err)
}
if err := pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
return fmt.Errorf("failed to write data to %s: %v", keyPemFile, err)
}
if err := keyOut.Close(); err != nil {
return fmt.Errorf("error closing %s: %v", keyPemFile, err)
}
log.Printf("wrote %s", keyPemFile)
return nil
}
func (obj *TLS) 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
}
}