85 lines
1.8 KiB
Go
85 lines
1.8 KiB
Go
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package secret
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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/sha256"
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"encoding/base64"
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"errors"
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"fmt"
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"io"
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"strings"
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)
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var ErrEmpty = errors.New("secret is empty")
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type Box struct {
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gcm cipher.AEAD
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}
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func NewBox(keyMaterial string) (*Box, error) {
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if keyMaterial == "" {
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return nil, fmt.Errorf("encryption key material is required")
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}
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sum := sha256.Sum256([]byte(keyMaterial))
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block, err := aes.NewCipher(sum[:])
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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(block)
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if err != nil {
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return nil, err
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}
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return &Box{gcm: gcm}, nil
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}
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func (b *Box) Encrypt(plain string) (string, error) {
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if plain == "" {
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return "", ErrEmpty
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}
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nonce := make([]byte, b.gcm.NonceSize())
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return "", err
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}
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ciphertext := b.gcm.Seal(nonce, nonce, []byte(plain), nil)
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return base64.StdEncoding.EncodeToString(ciphertext), nil
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}
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func (b *Box) Decrypt(encoded string) (string, error) {
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if encoded == "" {
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return "", ErrEmpty
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}
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raw, err := base64.StdEncoding.DecodeString(encoded)
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if err != nil {
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return "", err
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}
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nonceSize := b.gcm.NonceSize()
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if len(raw) < nonceSize {
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return "", fmt.Errorf("invalid ciphertext")
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}
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nonce, ciphertext := raw[:nonceSize], raw[nonceSize:]
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plain, err := b.gcm.Open(nil, nonce, ciphertext, nil)
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if err != nil {
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return "", err
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}
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return string(plain), nil
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}
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func IsDecryptFailure(err error) bool {
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if err == nil {
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return false
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}
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return strings.Contains(err.Error(), "message authentication failed")
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}
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func DecryptHint(err error) error {
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if err == nil {
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return nil
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}
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if IsDecryptFailure(err) {
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return fmt.Errorf("DNS API 凭据无法解密，请在 DDNS 页面重新保存 API Token（服务加密密钥可能已变更）")
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}
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return err
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}
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