157 lines
3.3 KiB
Go
157 lines
3.3 KiB
Go
package backend
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import (
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"archive/zip"
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"bytes"
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"context"
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"crypto/rsa"
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"crypto/x509"
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"encoding/pem"
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"errors"
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"fmt"
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"io"
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"os"
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"path/filepath"
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"github.com/wailsapp/wails/v2/pkg/runtime"
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)
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type Decryptor struct {
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ctx context.Context
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}
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func NewDecryptor() *Decryptor {
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return &Decryptor{}
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}
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func (d *Decryptor) OnStartup(ctx context.Context) {
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d.ctx = ctx
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fmt.Printf("ctx: %v\n", ctx)
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}
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func (d *Decryptor) SelectPrivateKeyFile() (string, error) {
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return runtime.OpenFileDialog(d.ctx, runtime.OpenDialogOptions{
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Title: "Select Private Key File",
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Filters: []runtime.FileFilter{
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{DisplayName: "PEM Files", Pattern: "*.pem"},
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},
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})
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}
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func (d *Decryptor) SelectEncryptedFile() (string, error) {
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return runtime.OpenFileDialog(d.ctx, runtime.OpenDialogOptions{
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Title: "Select Encrypted Zip File",
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Filters: []runtime.FileFilter{
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{DisplayName: "Encrypted Zip", Pattern: "*.zip"},
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},
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})
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}
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func (d *Decryptor) SelectOutputDirectory() (string, error) {
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return runtime.OpenDirectoryDialog(d.ctx, runtime.OpenDialogOptions{
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Title: "Select Output Directory",
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})
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}
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func (d *Decryptor) DecryptHybridZip(encryptedZipPath string, privKeyPath string, outputDir string) error {
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r, err := zip.OpenReader(encryptedZipPath)
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if err != nil {
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return err
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}
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defer r.Close()
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var encData, encKey []byte
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for _, f := range r.File {
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rc, _ := f.Open()
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data, _ := io.ReadAll(rc)
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rc.Close()
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fmt.Printf("f.Name: %v\n", f.Name)
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switch f.Name {
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case "encrypted_data.bin":
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encData = data
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case "encrypted_key.bin":
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encKey = data
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}
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}
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if encData == nil || encKey == nil {
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return errors.New("missing encrypted files")
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}
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privKey, err := loadPrivateKey(privKeyPath)
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if err != nil {
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return err
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}
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aesKey, err := rsa.DecryptPKCS1v15(rand.Reader, privKey, encKey)
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if err != nil {
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return err
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}
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zipData, err := decryptAES(encData, aesKey)
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if err != nil {
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return err
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}
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zipReader, err := zip.NewReader(bytes.NewReader(zipData), int64(len(zipData)))
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if err != nil {
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return err
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}
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var originalFolderName string
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for _, f := range zipReader.File {
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dirPath := filepath.Dir(f.Name)
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if len(dirPath) > 0 && originalFolderName == "" {
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originalFolderName = dirPath
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}
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}
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if originalFolderName == "" {
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return errors.New("failed to detect original folder name")
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}
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outputZip := filepath.Join(outputDir, originalFolderName+".zip")
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err = os.WriteFile(outputZip, zipData, 0644)
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if err != nil {
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return fmt.Errorf("failed to write decrypted zip file: %w", err)
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}
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return nil
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}
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func loadPrivateKey(path string) (*rsa.PrivateKey, error) {
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data, err := os.ReadFile(path)
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if err != nil {
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return nil, err
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}
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block, _ := pem.Decode(data)
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if block == nil || block.Type != "PRIVATE KEY" {
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return nil, errors.New("invalid private key format")
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}
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priv, err := x509.ParsePKCS8PrivateKey(block.Bytes)
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if err != nil {
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return nil, err
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}
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return priv.(*rsa.PrivateKey), nil
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}
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func decryptAES(cipherData, key []byte) ([]byte, error) {
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block, err := aes.NewCipher(key)
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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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nonceSize := gcm.NonceSize()
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if len(cipherData) < nonceSize {
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return nil, fmt.Errorf("cipher data too short")
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}
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nonce, cipherText := cipherData[:nonceSize], cipherData[nonceSize:]
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return gcm.Open(nil, nonce, cipherText, nil)
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}
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