packer-cn/communicator/ssh/keychain.go

82 lines
1.9 KiB
Go

package ssh
import (
"code.google.com/p/gosshold/ssh"
"crypto"
"crypto/dsa"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"errors"
"io"
)
// SimpleKeychain makes it easy to use private keys in order to connect
// via SSH, since the interface exposed by Go isn't the easiest to use
// right away.
type SimpleKeychain struct {
keys []interface{}
}
// AddPEMKey adds a simple PEM encoded private key to the keychain.
func (k *SimpleKeychain) AddPEMKey(key string) (err error) {
block, _ := pem.Decode([]byte(key))
if block == nil {
return errors.New("no block in key")
}
var rsakey interface{}
rsakey, err = x509.ParsePKCS1PrivateKey(block.Bytes)
if err != nil {
rsakey, err = x509.ParsePKCS8PrivateKey(block.Bytes)
}
if err != nil {
return
}
k.keys = append(k.keys, rsakey)
return
}
// AddPEMKeyPassword adds a PEM encoded private key that is protected by
// a password to the keychain.
func (k *SimpleKeychain) AddPEMKeyPassword(key string, password string) (err error) {
block, _ := pem.Decode([]byte(key))
bytes, _ := x509.DecryptPEMBlock(block, []byte(password))
rsakey, err := x509.ParsePKCS1PrivateKey(bytes)
if err != nil {
return
}
k.keys = append(k.keys, rsakey)
return
}
// Key method for ssh.ClientKeyring interface
func (k *SimpleKeychain) Key(i int) (ssh.PublicKey, error) {
if i < 0 || i >= len(k.keys) {
return nil, nil
}
switch key := k.keys[i].(type) {
case *rsa.PrivateKey:
return ssh.NewPublicKey(&key.PublicKey)
case *dsa.PrivateKey:
return ssh.NewPublicKey(&key.PublicKey)
}
panic("unknown key type")
}
// Sign method for ssh.ClientKeyring interface
func (k *SimpleKeychain) Sign(i int, rand io.Reader, data []byte) (sig []byte, err error) {
hashFunc := crypto.SHA1
h := hashFunc.New()
h.Write(data)
digest := h.Sum(nil)
switch key := k.keys[i].(type) {
case *rsa.PrivateKey:
return rsa.SignPKCS1v15(rand, key, hashFunc, digest)
}
return nil, errors.New("ssh: unknown key type")
}