certificates/cmd/step-pkcs11-init/main.go
Mariano Cano 23b8f45b37 Address gosec warnings
Most if not all false positives
2022-08-18 17:46:20 -07:00

550 lines
15 KiB
Go

package main
import (
"context"
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/sha1" // nolint:gosec // used to create the Subject Key Identifier by RFC 5280
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"flag"
"fmt"
"math/big"
"os"
"runtime"
"time"
"github.com/pkg/errors"
"go.step.sm/cli-utils/fileutil"
"go.step.sm/cli-utils/ui"
"go.step.sm/crypto/kms"
"go.step.sm/crypto/kms/apiv1"
"go.step.sm/crypto/kms/uri"
"go.step.sm/crypto/pemutil"
// Enable pkcs11.
_ "go.step.sm/crypto/kms/pkcs11"
)
// Config is a mapping of the cli flags.
type Config struct {
KMS string
GenerateRoot bool
RootObject string
RootKeyObject string
RootSubject string
RootPath string
CrtObject string
CrtPath string
CrtKeyObject string
CrtSubject string
CrtKeyPath string
SSHHostKeyObject string
SSHUserKeyObject string
RootFile string
KeyFile string
Pin string
PinFile string
NoCerts bool
EnableSSH bool
Force bool
Extractable bool
}
// Validate checks the flags in the config.
func (c *Config) Validate() error {
switch {
case c.KMS == "":
return errors.New("flag `--kms` is required")
case c.CrtPath == "":
return errors.New("flag `--crt-cert-path` is required")
case c.RootFile != "" && c.KeyFile == "":
return errors.New("flag `--root-cert-file` requires flag `--root-key-file`")
case c.KeyFile != "" && c.RootFile == "":
return errors.New("flag `--root-key-file` requires flag `--root-cert-file`")
case c.RootFile == "" && c.RootObject == "":
return errors.New("one of flag `--root-cert-file` or `--root-cert-obj` is required")
case c.KeyFile == "" && c.RootKeyObject == "":
return errors.New("one of flag `--root-key-file` or `--root-key-obj` is required")
case c.CrtKeyPath == "" && c.CrtKeyObject == "":
return errors.New("one of flag `--crt-key-path` or `--crt-key-obj` is required")
case c.RootFile == "" && c.GenerateRoot && c.RootKeyObject == "":
return errors.New("flag `--root-gen` requires flag `--root-key-obj`")
case c.RootFile == "" && c.GenerateRoot && c.RootPath == "":
return errors.New("flag `--root-gen` requires `--root-cert-path`")
case c.Pin != "" && c.PinFile != "":
return errors.New("Only set one of pin and pin-file")
default:
if c.RootFile != "" {
c.GenerateRoot = false
c.RootObject = ""
c.RootKeyObject = ""
}
if c.CrtKeyPath != "" {
c.CrtObject = ""
c.CrtKeyObject = ""
}
if !c.EnableSSH {
c.SSHHostKeyObject = ""
c.SSHUserKeyObject = ""
}
return nil
}
}
func main() {
var kmsuri string
switch runtime.GOOS {
case "darwin":
kmsuri = "pkcs11:module-path=/usr/local/lib/pkcs11/yubihsm_pkcs11.dylib;token=YubiHSM"
case "linux":
kmsuri = "pkcs11:module-path=/usr/lib/x86_64-linux-gnu/pkcs11/yubihsm_pkcs11.so;token=YubiHSM"
case "windows":
if home, err := os.UserHomeDir(); err == nil {
kmsuri = "pkcs11:module-path=" + home + "\\yubihsm2-sdk\\bin\\yubihsm_pkcs11.dll" + ";token=YubiHSM"
}
}
var c Config
flag.StringVar(&c.KMS, "kms", kmsuri, "PKCS #11 URI with the module-path and token to connect to the module.")
flag.StringVar(&c.Pin, "pin", "", "PKCS #11 PIN")
flag.StringVar(&c.PinFile, "pin-file", "", "PKCS #11 PIN File")
// Option 1: Generate new root
flag.BoolVar(&c.GenerateRoot, "root-gen", true, "Enable the generation of a root key.")
flag.StringVar(&c.RootSubject, "root-name", "PKCS #11 Smallstep Root", "Subject and Issuer of the root certificate.")
flag.StringVar(&c.RootObject, "root-cert-obj", "pkcs11:id=7330;object=root-cert", "PKCS #11 URI with object id and label to store the root certificate.")
flag.StringVar(&c.RootKeyObject, "root-key-obj", "pkcs11:id=7330;object=root-key", "PKCS #11 URI with object id and label to store the root key.")
// Option 2: Read root from disk and sign intermediate
flag.StringVar(&c.RootFile, "root-cert-file", "", "Path to the root certificate to use.")
flag.StringVar(&c.KeyFile, "root-key-file", "", "Path to the root key to use.")
// Option 3: Generate certificate signing request
flag.StringVar(&c.CrtSubject, "crt-name", "PKCS #11 Smallstep Intermediate", "Subject of the intermediate certificate.")
flag.StringVar(&c.CrtObject, "crt-cert-obj", "pkcs11:id=7331;object=intermediate-cert", "PKCS #11 URI with object id and label to store the intermediate certificate.")
flag.StringVar(&c.CrtKeyObject, "crt-key-obj", "pkcs11:id=7331;object=intermediate-key", "PKCS #11 URI with object id and label to store the intermediate certificate.")
// SSH certificates
flag.BoolVar(&c.EnableSSH, "ssh", false, "Enable the creation of ssh keys.")
flag.StringVar(&c.SSHHostKeyObject, "ssh-host-key", "pkcs11:id=7332;object=ssh-host-key", "PKCS #11 URI with object id and label to store the key used to sign SSH host certificates.")
flag.StringVar(&c.SSHUserKeyObject, "ssh-user-key", "pkcs11:id=7333;object=ssh-user-key", "PKCS #11 URI with object id and label to store the key used to sign SSH user certificates.")
// Output files
flag.StringVar(&c.RootPath, "root-cert-path", "root_ca.crt", "Location to write the root certificate.")
flag.StringVar(&c.CrtPath, "crt-cert-path", "intermediate_ca.crt", "Location to write the intermediate certificate.")
flag.StringVar(&c.CrtKeyPath, "crt-key-path", "", "Location to write the intermediate private key.")
// Others
flag.BoolVar(&c.NoCerts, "no-certs", false, "Do not store certificates in the module.")
flag.BoolVar(&c.Force, "force", false, "Force the delete of previous keys.")
flag.BoolVar(&c.Extractable, "extractable", false, "Allow export of private keys under wrap.")
flag.Usage = usage
flag.Parse()
if err := c.Validate(); err != nil {
fatal(err)
}
u, err := uri.ParseWithScheme("pkcs11", c.KMS)
if err != nil {
fatal(err)
}
// Initialize windows terminal
ui.Init()
switch {
case u.Get("pin-value") != "":
case u.Get("pin-source") != "":
case c.Pin != "":
case c.PinFile != "":
content, err := os.ReadFile(c.PinFile)
if err != nil {
fatal(err)
}
c.Pin = string(content)
default:
pin, err := ui.PromptPassword("What is the PKCS#11 PIN?")
if err != nil {
fatal(err)
}
c.Pin = string(pin)
}
k, err := kms.New(context.Background(), apiv1.Options{
Type: apiv1.PKCS11,
URI: c.KMS,
Pin: c.Pin,
})
if err != nil {
fatal(err)
}
defer func() {
_ = k.Close()
}()
// Check if the slots are empty, fail if they are not
certUris := []string{
c.RootObject, c.CrtObject,
}
keyUris := []string{
c.RootKeyObject, c.CrtKeyObject,
c.SSHHostKeyObject, c.SSHUserKeyObject,
}
if !c.Force {
for _, u := range certUris {
if u != "" && !c.NoCerts {
checkObject(k, u)
checkCertificate(k, u)
}
}
for _, u := range keyUris {
if u != "" {
checkObject(k, u)
}
}
} else {
deleter, ok := k.(interface {
DeleteKey(uri string) error
DeleteCertificate(uri string) error
})
if ok {
for _, u := range certUris {
if u != "" && !c.NoCerts {
// Some HSMs like Nitrokey will overwrite the key with the
// certificate label.
if err := deleter.DeleteKey(u); err != nil {
fatalClose(err, k)
}
if err := deleter.DeleteCertificate(u); err != nil {
fatalClose(err, k)
}
}
}
for _, u := range keyUris {
if u != "" {
if err := deleter.DeleteKey(u); err != nil {
fatalClose(err, k)
}
}
}
}
}
if err := createPKI(k, c); err != nil {
fatalClose(err, k)
}
// Reset windows terminal
ui.Reset()
}
func fatal(err error) {
if os.Getenv("STEPDEBUG") == "1" {
fmt.Fprintf(os.Stderr, "%+v\n", err)
} else {
fmt.Fprintln(os.Stderr, err)
}
ui.Reset()
os.Exit(1)
}
func fatalClose(err error, k kms.KeyManager) {
_ = k.Close()
fatal(err)
}
func usage() {
fmt.Fprintln(os.Stderr, "Usage: step-pkcs11-init")
fmt.Fprintln(os.Stderr, `
The step-pkcs11-init command initializes a public key infrastructure (PKI)
to be used by step-ca.
This tool is experimental and in the future it will be integrated in step cli.
OPTIONS`)
fmt.Fprintln(os.Stderr)
flag.PrintDefaults()
fmt.Fprintf(os.Stderr, `
COPYRIGHT
(c) 2018-%d Smallstep Labs, Inc.
`, time.Now().Year())
os.Exit(1)
}
func checkCertificate(k kms.KeyManager, rawuri string) {
if cm, ok := k.(kms.CertificateManager); ok {
if _, err := cm.LoadCertificate(&apiv1.LoadCertificateRequest{
Name: rawuri,
}); err == nil {
fmt.Fprintf(os.Stderr, "⚠️ Your PKCS #11 module already has a certificate on %s.\n", rawuri)
fmt.Fprintln(os.Stderr, " If you want to delete it and start fresh, use `--force`.")
_ = k.Close()
os.Exit(1)
}
}
}
func checkObject(k kms.KeyManager, rawuri string) {
if _, err := k.GetPublicKey(&apiv1.GetPublicKeyRequest{
Name: rawuri,
}); err == nil {
fmt.Fprintf(os.Stderr, "⚠️ Your PKCS #11 module already has a key on %s.\n", rawuri)
fmt.Fprintln(os.Stderr, " If you want to delete it and start fresh, use `--force`.")
_ = k.Close()
os.Exit(1)
}
}
func createPKI(k kms.KeyManager, c Config) error {
var err error
ui.Println("Creating PKI ...")
now := time.Now()
// Root Certificate
var signer crypto.Signer
var root *x509.Certificate
switch {
case c.GenerateRoot:
resp, err := k.CreateKey(&apiv1.CreateKeyRequest{
Name: c.RootKeyObject,
SignatureAlgorithm: apiv1.ECDSAWithSHA256,
Extractable: c.Extractable,
})
if err != nil {
return err
}
signer, err = k.CreateSigner(&resp.CreateSignerRequest)
if err != nil {
return err
}
template := &x509.Certificate{
IsCA: true,
NotBefore: now,
NotAfter: now.Add(time.Hour * 24 * 365 * 10),
KeyUsage: x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
BasicConstraintsValid: true,
MaxPathLen: 1,
MaxPathLenZero: false,
Issuer: pkix.Name{CommonName: c.RootSubject},
Subject: pkix.Name{CommonName: c.RootSubject},
SerialNumber: mustSerialNumber(),
SubjectKeyId: mustSubjectKeyID(resp.PublicKey),
AuthorityKeyId: mustSubjectKeyID(resp.PublicKey),
}
b, err := x509.CreateCertificate(rand.Reader, template, template, resp.PublicKey, signer)
if err != nil {
return err
}
root, err = x509.ParseCertificate(b)
if err != nil {
return errors.Wrap(err, "error parsing root certificate")
}
if cm, ok := k.(kms.CertificateManager); ok && c.RootObject != "" && !c.NoCerts {
if err := cm.StoreCertificate(&apiv1.StoreCertificateRequest{
Name: c.RootObject,
Certificate: root,
Extractable: c.Extractable,
}); err != nil {
return err
}
} else {
c.RootObject = ""
}
if err := fileutil.WriteFile(c.RootPath, pem.EncodeToMemory(&pem.Block{
Type: "CERTIFICATE",
Bytes: b,
}), 0600); err != nil {
return err
}
ui.PrintSelected("Root Key", resp.Name)
ui.PrintSelected("Root Certificate", c.RootPath)
if c.RootObject != "" {
ui.PrintSelected("Root Certificate Object", c.RootObject)
}
case c.RootFile != "" && c.KeyFile != "": // Read Root From File
root, err = pemutil.ReadCertificate(c.RootFile)
if err != nil {
return err
}
key, err := pemutil.Read(c.KeyFile)
if err != nil {
return err
}
var ok bool
if signer, ok = key.(crypto.Signer); !ok {
return errors.Errorf("key type '%T' does not implement a signer", key)
}
}
// Intermediate Certificate
var keyName string
var publicKey crypto.PublicKey
var intSigner crypto.Signer
if c.CrtKeyPath != "" {
priv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
if err != nil {
return errors.Wrap(err, "error creating intermediate key")
}
pass, err := ui.PromptPasswordGenerate("What do you want your password to be? [leave empty and we'll generate one]",
ui.WithRichPrompt())
if err != nil {
return err
}
_, err = pemutil.Serialize(priv, pemutil.WithPassword(pass), pemutil.ToFile(c.CrtKeyPath, 0600))
if err != nil {
return err
}
publicKey = priv.Public()
intSigner = priv
} else {
resp, err := k.CreateKey(&apiv1.CreateKeyRequest{
Name: c.CrtKeyObject,
SignatureAlgorithm: apiv1.ECDSAWithSHA256,
Extractable: c.Extractable,
})
if err != nil {
return err
}
publicKey = resp.PublicKey
keyName = resp.Name
intSigner, err = k.CreateSigner(&resp.CreateSignerRequest)
if err != nil {
return err
}
}
if root != nil {
template := &x509.Certificate{
IsCA: true,
NotBefore: now,
NotAfter: now.Add(time.Hour * 24 * 365 * 10),
KeyUsage: x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
BasicConstraintsValid: true,
MaxPathLen: 0,
MaxPathLenZero: true,
Issuer: root.Subject,
Subject: pkix.Name{CommonName: c.CrtSubject},
SerialNumber: mustSerialNumber(),
SubjectKeyId: mustSubjectKeyID(publicKey),
}
b, err := x509.CreateCertificate(rand.Reader, template, root, publicKey, signer)
if err != nil {
return err
}
intermediate, err := x509.ParseCertificate(b)
if err != nil {
return errors.Wrap(err, "error parsing intermediate certificate")
}
if cm, ok := k.(kms.CertificateManager); ok && c.CrtObject != "" && !c.NoCerts {
if err := cm.StoreCertificate(&apiv1.StoreCertificateRequest{
Name: c.CrtObject,
Certificate: intermediate,
Extractable: c.Extractable,
}); err != nil {
return err
}
} else {
c.CrtObject = ""
}
if err := fileutil.WriteFile(c.CrtPath, pem.EncodeToMemory(&pem.Block{
Type: "CERTIFICATE",
Bytes: b,
}), 0600); err != nil {
return err
}
} else {
// No root available, generate CSR for external root.
csrTemplate := x509.CertificateRequest{
Subject: pkix.Name{CommonName: c.CrtSubject},
SignatureAlgorithm: x509.ECDSAWithSHA256,
}
// step: generate the csr request
csrCertificate, err := x509.CreateCertificateRequest(rand.Reader, &csrTemplate, intSigner)
if err != nil {
return err
}
if err := fileutil.WriteFile(c.CrtPath, pem.EncodeToMemory(&pem.Block{
Type: "CERTIFICATE REQUEST",
Bytes: csrCertificate,
}), 0600); err != nil {
return err
}
}
if c.CrtKeyPath != "" {
ui.PrintSelected("Intermediate Key", c.CrtKeyPath)
} else {
ui.PrintSelected("Intermediate Key", keyName)
}
if root != nil {
ui.PrintSelected("Intermediate Certificate", c.CrtPath)
if c.CrtObject != "" {
ui.PrintSelected("Intermediate Certificate Object", c.CrtObject)
}
} else {
ui.PrintSelected("Intermediate Certificate Request", c.CrtPath)
}
if c.SSHHostKeyObject != "" {
resp, err := k.CreateKey(&apiv1.CreateKeyRequest{
Name: c.SSHHostKeyObject,
SignatureAlgorithm: apiv1.ECDSAWithSHA256,
})
if err != nil {
return err
}
ui.PrintSelected("SSH Host Key", resp.Name)
}
if c.SSHUserKeyObject != "" {
resp, err := k.CreateKey(&apiv1.CreateKeyRequest{
Name: c.SSHUserKeyObject,
SignatureAlgorithm: apiv1.ECDSAWithSHA256,
})
if err != nil {
return err
}
ui.PrintSelected("SSH User Key", resp.Name)
}
return nil
}
func mustSerialNumber() *big.Int {
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
sn, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
panic(err)
}
return sn
}
func mustSubjectKeyID(key crypto.PublicKey) []byte {
b, err := x509.MarshalPKIXPublicKey(key)
if err != nil {
panic(err)
}
// nolint:gosec // used to create the Subject Key Identifier by RFC 5280
hash := sha1.Sum(b)
return hash[:]
}