packer-cn/builder/googlecompute/private_key.go

43 lines
1.1 KiB
Go

package googlecompute
import (
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"io/ioutil"
)
// processPrivateKeyFile takes a private key file and an optional passphrase
// and decodes it to a byte slice.
func processPrivateKeyFile(privateKeyFile, passphrase string) ([]byte, error) {
rawPrivateKeyBytes, err := ioutil.ReadFile(privateKeyFile)
if err != nil {
return nil, fmt.Errorf("Failed loading private key file: %s", err)
}
PEMBlock, _ := pem.Decode(rawPrivateKeyBytes)
if PEMBlock == nil {
return nil, fmt.Errorf("%s does not contain a vaild private key", privateKeyFile)
}
if x509.IsEncryptedPEMBlock(PEMBlock) {
if passphrase == "" {
return nil, errors.New("a passphrase must be specified when using an encrypted private key")
}
decryptedPrivateKeyBytes, err := x509.DecryptPEMBlock(PEMBlock, []byte(passphrase))
if err != nil {
return nil, fmt.Errorf("Failed decrypting private key: %s", err)
}
b := &pem.Block{
Type: "RSA PRIVATE KEY",
Bytes: decryptedPrivateKeyBytes,
}
return pem.EncodeToMemory(b), nil
}
return rawPrivateKeyBytes, nil
}