108 lines
2.6 KiB
Go
108 lines
2.6 KiB
Go
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package shopify
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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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"io"
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"strings"
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"github.com/descrybe/descrybe-v2/apps/api/internal/config"
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)
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const encPrefix = "enc:v1:"
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// DeriveKey builds a 32-byte AES key. Prefer explicitKey; fall back to hashed material.
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// In production, explicitKey is required; empty returns nil (fail closed).
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func DeriveKey(explicitKey, fallbackMaterial string) []byte {
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explicitKey = strings.TrimSpace(explicitKey)
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if explicitKey != "" {
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if b, err := decodeKeyMaterial(explicitKey); err == nil {
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return b
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}
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sum := sha256.Sum256([]byte(explicitKey))
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return sum[:]
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}
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if config.IsProductionEnv() {
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return nil
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}
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sum := sha256.Sum256([]byte("descrybe-shopify-v1|" + fallbackMaterial))
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return sum[:]
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}
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func decodeKeyMaterial(s string) ([]byte, error) {
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if b, err := base64.StdEncoding.DecodeString(s); err == nil && len(b) == 32 {
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return b, nil
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}
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if b, err := base64.RawStdEncoding.DecodeString(s); err == nil && len(b) == 32 {
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return b, nil
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}
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if b, err := hex.DecodeString(s); err == nil && len(b) == 32 {
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return b, nil
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}
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return nil, errors.New("invalid key material")
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}
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func EncryptSecret(key []byte, plaintext string) (string, error) {
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if plaintext == "" {
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return "", nil
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}
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if len(key) != 32 {
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return "", errors.New("encryption key must be 32 bytes")
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return "", 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 "", err
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}
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nonce := make([]byte, 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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sealed := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
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return encPrefix + base64.RawStdEncoding.EncodeToString(sealed), nil
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}
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func DecryptSecret(key []byte, stored string) (string, error) {
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if stored == "" {
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return "", nil
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}
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if !strings.HasPrefix(stored, encPrefix) {
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if config.IsProductionEnv() {
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return "", errors.New("plaintext secrets are not allowed when APP_ENV=production")
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}
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return stored, nil
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}
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if len(key) != 32 {
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return "", errors.New("encryption key must be 32 bytes")
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}
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raw, err := base64.RawStdEncoding.DecodeString(strings.TrimPrefix(stored, encPrefix))
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if err != nil {
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return "", err
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return "", 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 "", err
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}
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if len(raw) < gcm.NonceSize() {
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return "", errors.New("ciphertext too short")
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}
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nonce, ciphertext := raw[:gcm.NonceSize()], raw[gcm.NonceSize():]
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plain, err := 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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