go-http-peering/cmd/keygen/util.go

package main

import (
	"bytes"
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"io/ioutil"
	"os"
	"syscall"

	"forge.cadoles.com/Cadoles/go-http-peering/crypto"
	"github.com/pkg/errors"

	"golang.org/x/crypto/ssh/terminal"
)

func getPassphrase() ([]byte, error) {
	passphrase, exists := os.LookupEnv("KEY_PASSPHRASE")
	if exists {
		return []byte(passphrase), nil
	}
	return askPassphrase()
}

func askPassphrase() ([]byte, error) {
	fmt.Print("Passphrase: ")
	passphrase, err := terminal.ReadPassword(syscall.Stdin)
	if err != nil {
		return nil, errors.WithStack(err)
	}
	fmt.Println()

	fmt.Print("Confirm passphrase: ")
	passphraseConfirmation, err := terminal.ReadPassword(syscall.Stdin)
	if err != nil {
		return nil, errors.WithStack(err)
	}
	fmt.Println()

	if !bytes.Equal(passphrase, passphraseConfirmation) {
		return nil, errors.New("passphrases does not match")
	}

	return passphrase, nil
}

func privateKeyToEncryptedPEM(key *rsa.PrivateKey, passphrase []byte) ([]byte, error) {
	if passphrase == nil {
		return nil, errors.New("passphrase cannot be empty")
	}

	// Convert it to pem
	block := &pem.Block{
		Type:  "RSA PRIVATE KEY",
		Bytes: x509.MarshalPKCS1PrivateKey(key),
	}

	block, err := x509.EncryptPEMBlock(rand.Reader, block.Type, block.Bytes, passphrase, x509.PEMCipherAES256)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return pem.EncodeToMemory(block), nil
}

func loadPrivateKey() (*rsa.PrivateKey, error) {
	if keyFile == "" {
		return nil, errors.New("you must specify a key file to load")
	}
	pem, err := ioutil.ReadFile(keyFile)
	if err != nil {
		return nil, errors.WithStack(err)
	}
	passphrase, err := getPassphrase()
	if err != nil {
		return nil, errors.WithStack(err)
	}
	privateKey, err := crypto.DecodePEMEncryptedPrivateKey(pem, passphrase)
	if err != nil {
		return nil, errors.WithStack(err)
	}
	return privateKey, nil
}

func handleError(err error) {
	if !debug {
		fmt.Printf("%+v\n", errors.WithStack(err))
	} else {
		panic(fmt.Sprintf("%+v", errors.WithStack(err)))
	}
	os.Exit(1)
}