package lnd import ( "bufio" "fmt" "os" "regexp" "strings" "syscall" "time" "github.com/btcsuite/btcd/btcutil/hdkeychain" "github.com/btcsuite/btcd/chaincfg" "github.com/lightningnetwork/lnd/aezeed" "golang.org/x/crypto/ssh/terminal" ) const ( MnemonicEnvName = "AEZEED_MNEMONIC" PassphraseEnvName = "AEZEED_PASSPHRASE" ) var ( numberDotsRegex = regexp.MustCompile(`[\d.\-\n\r\t]*`) multipleSpaces = regexp.MustCompile(" [ ]+") ) func ReadAezeed(params *chaincfg.Params) (*hdkeychain.ExtendedKey, time.Time, error) { // To automate things with chantools, we also offer reading the seed // from environment variables. mnemonicStr := strings.TrimSpace(os.Getenv(MnemonicEnvName)) // If nothing is set in the environment, read the seed from the // terminal. if mnemonicStr == "" { var err error // We'll now prompt the user to enter in their 24-word mnemonic. fmt.Printf("Input your 24-word mnemonic separated by spaces: ") reader := bufio.NewReader(os.Stdin) mnemonicStr, err = reader.ReadString('\n') if err != nil { return nil, time.Unix(0, 0), err } } // We'll trim off extra spaces, and ensure the mnemonic is all // lower case. mnemonicStr = strings.TrimSpace(mnemonicStr) mnemonicStr = strings.ToLower(mnemonicStr) // To allow the tool to also accept the copy/pasted version of the // backup text (which contains numbers and dots and multiple spaces), // we do some more cleanup with regex. mnemonicStr = numberDotsRegex.ReplaceAllString(mnemonicStr, "") mnemonicStr = multipleSpaces.ReplaceAllString(mnemonicStr, " ") mnemonicStr = strings.TrimSpace(mnemonicStr) cipherSeedMnemonic := strings.Split(mnemonicStr, " ") fmt.Println() if len(cipherSeedMnemonic) != 24 { return nil, time.Unix(0, 0), fmt.Errorf("wrong cipher seed "+ "mnemonic length: got %v words, expecting %v words", len(cipherSeedMnemonic), 24) } // Additionally, the user may have a passphrase, that will also need to // be provided so the daemon can properly decipher the cipher seed. // Try the environment variable first. passphrase := strings.TrimSpace(os.Getenv(PassphraseEnvName)) // Because we cannot differentiate between an empty and a non-existent // environment variable, we need a special character that indicates that // no passphrase should be used. We use a single dash (-) for that as // that would be too short for a passphrase anyway. var passphraseBytes []byte switch { // The user indicated in the environment variable that no passphrase // should be used. We don't set any value. case passphrase == "-": // The environment variable didn't contain anything, we'll read the // passphrase from the terminal. case passphrase == "": fmt.Printf("Input your cipher seed passphrase (press enter " + "if your seed doesn't have a passphrase): ") var err error passphraseBytes, err = terminal.ReadPassword( int(syscall.Stdin), //nolint ) if err != nil { return nil, time.Unix(0, 0), err } fmt.Println() // There was a password in the environment, just convert it to bytes. default: passphraseBytes = []byte(passphrase) } var mnemonic aezeed.Mnemonic copy(mnemonic[:], cipherSeedMnemonic) // If we're unable to map it back into the ciphertext, then either the // mnemonic is wrong, or the passphrase is wrong. cipherSeed, err := mnemonic.ToCipherSeed(passphraseBytes) if err != nil { return nil, time.Unix(0, 0), fmt.Errorf("failed to decrypt "+ "seed with passphrase: %w", err) } rootKey, err := hdkeychain.NewMaster(cipherSeed.Entropy[:], params) if err != nil { return nil, time.Unix(0, 0), fmt.Errorf("failed to derive " + "master extended key") } return rootKey, cipherSeed.BirthdayTime(), nil }