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