k3s/pkg/cluster/encrypt.go
Luther Monson 9a849b1bb7
[master] changing package to k3s-io (#4846)
* changing package to k3s-io

Signed-off-by: Luther Monson <luther.monson@gmail.com>

Co-authored-by: Derek Nola <derek.nola@suse.com>
2022-03-02 15:47:27 -08:00

87 lines
2.2 KiB
Go

package cluster
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"crypto/sha1"
"crypto/sha256"
"encoding/base64"
"encoding/hex"
"fmt"
"io"
"strings"
"github.com/k3s-io/k3s/pkg/token"
"golang.org/x/crypto/pbkdf2"
)
// storageKey returns the etcd key for storing bootstrap data for a given passphrase.
// The key is derived from the sha256 hash of the passphrase.
func storageKey(passphrase string) string {
return "/bootstrap/" + keyHash(passphrase)
}
// keyHash returns the first 12 characters of the sha256 sum of the passphrase.
func keyHash(passphrase string) string {
d := sha256.New()
d.Write([]byte(passphrase))
return hex.EncodeToString(d.Sum(nil)[:])[:12]
}
// encrypt encrypts a byte slice using aes+gcm with a pbkdf2 key derived from the passphrase and a random salt.
// It returns a byte slice containing the salt and base64-encoded ciphertext.
func encrypt(passphrase string, plaintext []byte) ([]byte, error) {
salt, err := token.Random(8)
if err != nil {
return nil, err
}
clearKey := pbkdf2.Key([]byte(passphrase), []byte(salt), 4096, 32, sha1.New)
key, err := aes.NewCipher(clearKey)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(key)
if err != nil {
return nil, err
}
nonce := make([]byte, gcm.NonceSize())
_, err = io.ReadFull(rand.Reader, nonce)
if err != nil {
return nil, err
}
sealed := gcm.Seal(nonce, nonce, plaintext, nil)
return []byte(salt + ":" + base64.StdEncoding.EncodeToString(sealed)), nil
}
// decrypt attempts to decrypt the byte slice using the supplied passphrase.
// The input byte slice should be the ciphertext output from the encrypt function.
func decrypt(passphrase string, ciphertext []byte) ([]byte, error) {
parts := strings.SplitN(string(ciphertext), ":", 2)
if len(parts) != 2 {
return nil, fmt.Errorf("invalid cipher text, not : delimited")
}
clearKey := pbkdf2.Key([]byte(passphrase), []byte(parts[0]), 4096, 32, sha1.New)
key, err := aes.NewCipher(clearKey)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(key)
if err != nil {
return nil, err
}
data, err := base64.StdEncoding.DecodeString(parts[1])
if err != nil {
return nil, err
}
return gcm.Open(nil, data[:gcm.NonceSize()], data[gcm.NonceSize():], nil)
}