woodpecker/pkg/yaml/secure/secure.go
2015-08-18 23:59:30 -07:00

115 lines
2.5 KiB
Go

package secure
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/base64"
"fmt"
"io"
"github.com/drone/drone/Godeps/_workspace/src/gopkg.in/yaml.v2"
)
// Parse parses and returns the secure section of the
// yaml file as plaintext parameters.
func Parse(key, raw string) (map[string]string, error) {
params, err := parseSecure(raw)
if err != nil {
return nil, err
}
err = DecryptMap(key, params)
return params, err
}
// Encrypt encrypts a string to base64 crypto using AES.
func Encrypt(key, text string) (_ string, err error) {
plaintext := []byte(text)
block, err := aes.NewCipher(trimKey(key))
if err != nil {
return
}
ciphertext := make([]byte, aes.BlockSize+len(plaintext))
iv := ciphertext[:aes.BlockSize]
if _, err = io.ReadFull(rand.Reader, iv); err != nil {
return
}
stream := cipher.NewCFBEncrypter(block, iv)
stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintext)
return base64.URLEncoding.EncodeToString(ciphertext), nil
}
// Decrypt decrtyps from base64 to decrypted string.
func Decrypt(key, text string) (_ string, err error) {
ciphertext, err := base64.URLEncoding.DecodeString(text)
if err != nil {
return
}
block, err := aes.NewCipher(trimKey(key))
if err != nil {
return
}
if len(ciphertext) < aes.BlockSize {
err = fmt.Errorf("ciphertext too short")
return
}
iv := ciphertext[:aes.BlockSize]
ciphertext = ciphertext[aes.BlockSize:]
stream := cipher.NewCFBDecrypter(block, iv)
stream.XORKeyStream(ciphertext, ciphertext)
return fmt.Sprintf("%s", ciphertext), nil
}
// DecryptMap decrypts a map of named parameters
// from base64 to decrypted string.
func DecryptMap(key string, params map[string]string) error {
var err error
for name, value := range params {
params[name], err = Decrypt(key, value)
if err != nil {
return err
}
}
return nil
}
// EncryptMap encrypts encrypts a map of string parameters
// to base64 crypto using AES.
func EncryptMap(key string, params map[string]string) error {
var err error
for name, value := range params {
params[name], err = Encrypt(key, value)
if err != nil {
return err
}
}
return nil
}
// helper function that trims a key to a maximum
// of 32 bytes to match the expected AES block size.
func trimKey(key string) []byte {
b := []byte(key)
if len(b) > 32 {
b = b[:32]
}
return b
}
// helper function to parse the Secure data from
// the raw yaml file.
func parseSecure(raw string) (map[string]string, error) {
data := struct {
Secure map[string]string
}{}
err := yaml.Unmarshal([]byte(raw), &data)
return data.Secure, err
}