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mirror of https://github.com/guggero/chantools synced 2024-11-15 06:12:49 +00:00
chantools/lnd/aezeed.go
2021-01-01 13:02:16 +01:00

121 lines
3.6 KiB
Go

package lnd
import (
"bufio"
"fmt"
"os"
"regexp"
"strings"
"syscall"
"time"
"github.com/btcsuite/btcd/chaincfg"
"github.com/btcsuite/btcutil/hdkeychain"
"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: %v", 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
}