VeillaxandClaude Sonnet 5.5
64101e00d2
CI / test (push) Successful in 1m20s
Moved out of Hammerhead's internal package so Sandbar can use it too. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
88 lines
2.4 KiB
Go
88 lines
2.4 KiB
Go
// Package secretbox encrypts small secrets (tokens, passwords, private keys)
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// before they are written to the database, using AES-256-GCM.
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//
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// Sealed values look like "enc1:<base64>". Opening a value that isn't sealed
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// returns it unchanged, so data written before encryption was turned on is
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// still readable and gets sealed the next time it is saved.
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package secretbox
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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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"encoding/hex"
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"errors"
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"strings"
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)
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const prefix = "enc1:"
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type Box struct{ aead cipher.AEAD }
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// GenerateKey returns a new random key in the form New accepts.
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func GenerateKey() string {
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b := make([]byte, 32)
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rand.Read(b)
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return base64.StdEncoding.EncodeToString(b)
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}
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// New builds a Box from a key given as base64 or hex of 32 bytes. Any other
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// text is treated as a passphrase and stretched with SHA-256.
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func New(key string) (*Box, error) {
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key = strings.TrimSpace(key)
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if key == "" {
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return nil, errors.New("empty key")
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}
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raw := decodeKey(key)
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block, err := aes.NewCipher(raw)
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if err != nil {
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return nil, err
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}
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aead, 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{aead: aead}, nil
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}
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func decodeKey(key string) []byte {
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if b, err := base64.StdEncoding.DecodeString(key); err == nil && len(b) == 32 {
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return b
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}
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if b, err := hex.DecodeString(key); err == nil && len(b) == 32 {
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return b
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}
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sum := sha256.Sum256([]byte(key))
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return sum[:]
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}
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// Seal encrypts s. The empty string stays empty so unset secrets stay visibly unset.
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func (b *Box) Seal(s string) string {
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if s == "" || strings.HasPrefix(s, prefix) {
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return s
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}
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nonce := make([]byte, b.aead.NonceSize())
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rand.Read(nonce)
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return prefix + base64.StdEncoding.EncodeToString(b.aead.Seal(nonce, nonce, []byte(s), nil))
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}
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// Open decrypts a sealed value. A wrong key or damaged data is an error, so a
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// bad key can never silently turn secrets into garbage.
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func (b *Box) Open(s string) (string, error) {
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if !strings.HasPrefix(s, prefix) {
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return s, nil
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}
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raw, err := base64.StdEncoding.DecodeString(s[len(prefix):])
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if err != nil || len(raw) < b.aead.NonceSize() {
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return "", errors.New("damaged secret")
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}
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n := b.aead.NonceSize()
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plain, err := b.aead.Open(nil, raw[:n], raw[n:], nil)
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if err != nil {
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return "", errors.New("can't decrypt a stored secret: is HAMMERHEAD_MASTER_KEY the key it was saved with?")
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}
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return string(plain), nil
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}
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