Add genimportscript command

README.md

@@ -10,6 +10,7 @@
   + [dumpchannels](#dumpchannels)
   + [filterbackup](#filterbackup)
   + [fixoldbackup](#fixoldbackup)
+  + [genimportscript](#genimportscript)
   + [forceclose](#forceclose)
   + [rescueclosed](#rescueclosed)
   + [showrootkey](#showrootkey)
@@ -54,16 +55,17 @@ Help Options:
   -h, --help             Show this help message
 
 Available commands:
-  derivekey      Derive a key with a specific derivation path from the BIP32 HD root key.
+  derivekey        Derive a key with a specific derivation path from the BIP32 HD root key.
-  dumpbackup     Dump the content of a channel.backup file.
+  dumpbackup       Dump the content of a channel.backup file.
-  dumpchannels   Dump all channel information from lnd's channel database.
+  dumpchannels     Dump all channel information from lnd's channel database.
-  filterbackup   Filter an lnd channel.backup file and remove certain channels.
+  filterbackup     Filter an lnd channel.backup file and remove certain channels.
-  fixoldbackup   Fixes an old channel.backup file that is affected by the lnd issue #3881 (unable to derive shachain root key).
+  fixoldbackup     Fixes an old channel.backup file that is affected by the lnd issue #3881 (unable to derive shachain root key).
-  forceclose     Force-close the last state that is in the channel.db provided.
+  forceclose       Force-close the last state that is in the channel.db provided.
-  rescueclosed   Try finding the private keys for funds that are in outputs of remotely force-closed channels.
+  genimportscript  Generate a script containing the on-chain keys of an lnd wallet that can be imported into other software like bitcoind.
-  showrootkey    Extract and show the BIP32 HD root key from the 24 word lnd aezeed.
+  rescueclosed     Try finding the private keys for funds that are in outputs of remotely force-closed channels.
-  summary        Compile a summary about the current state of channels.
+  showrootkey      Extract and show the BIP32 HD root key from the 24 word lnd aezeed.
-  sweeptimelock  Sweep the force-closed state after the time lock has expired.
+  summary          Compile a summary about the current state of channels.
+  sweeptimelock    Sweep the force-closed state after the time lock has expired.
 ```
 
 ## Commands
@@ -213,6 +215,38 @@ chantools --fromsummary results/summary-xxxx-yyyy.json \
   --publish
 ```
 
+### genimportscript
+
+```text
+Usage:
+  chantools [OPTIONS] genimportscript [genimportscript-OPTIONS]
+
+[genimportscript command options]
+          --rootkey=        BIP32 HD root key to use. Leave empty to prompt for lnd 24 word aezeed.
+          --format=         The format of the generated import script. Currently supported are: bitcoin-cli, bitcoin-cli-watchonly.
+          --recoverywindow= The number of keys to scan per internal/external branch. The output will consist of double this amount of keys. (default 2500)
+          --rescanfrom=     The block number to rescan from. Will be set automatically from the wallet birthday if the lnd 24 word aezeed is entered. (default 500000)
+```
+
+Generates a script that contains all on-chain private (or public) keys derived
+from an lnd 24 word aezeed wallet. That script can then be imported into other
+software like bitcoind.
+
+The following script formats are currently supported:
+* `bitcoin-cli`: Creates a list of `bitcoin-cli importprivkey` commands that can
+  be used in combination with a `bitcoind` full node to recover the funds locked
+  in those private keys.
+* `bitcoin-cli-watchonly`: Does the same as `bitcoin-cli` but with the
+  `bitcoin-cli importpubkey` command. That means, only the public keys are 
+  imported into `bitcoind` to watch the UTXOs of those keys. The funds cannot be
+  spent that way as they are watch-only.
+
+Example command:
+
+```bash
+chantools genimportscript --format bitcoin-cli --recoverywindow 5000
+```
+
 ### rescueclosed
 
 ```text

cmd/chantools/derivekey.go

@@ -28,7 +28,7 @@ func (c *deriveKeyCommand) Execute(_ []string) error {
 		extendedKey, err = hdkeychain.NewKeyFromString(c.RootKey)
 
 	default:
-		extendedKey, err = rootKeyFromConsole()
+		extendedKey, _, err = rootKeyFromConsole()
 	}
 	if err != nil {
 		return fmt.Errorf("error reading root key: %v", err)

cmd/chantools/dumpbackup.go

@@ -30,7 +30,7 @@ func (c *dumpBackupCommand) Execute(_ []string) error {
 		extendedKey, err = hdkeychain.NewKeyFromString(c.RootKey)
 
 	default:
-		extendedKey, err = rootKeyFromConsole()
+		extendedKey, _, err = rootKeyFromConsole()
 	}
 	if err != nil {
 		return fmt.Errorf("error reading root key: %v", err)

cmd/chantools/filterbackup.go

@@ -32,7 +32,7 @@ func (c *filterBackupCommand) Execute(_ []string) error {
 		extendedKey, err = hdkeychain.NewKeyFromString(c.RootKey)
 
 	default:
-		extendedKey, err = rootKeyFromConsole()
+		extendedKey, _, err = rootKeyFromConsole()
 	}
 	if err != nil {
 		return fmt.Errorf("error reading root key: %v", err)

cmd/chantools/fixoldbackup.go

@@ -30,7 +30,7 @@ func (c *fixOldBackupCommand) Execute(_ []string) error {
 		extendedKey, err = hdkeychain.NewKeyFromString(c.RootKey)
 
 	default:
-		extendedKey, err = rootKeyFromConsole()
+		extendedKey, _, err = rootKeyFromConsole()
 	}
 	if err != nil {
 		return fmt.Errorf("error reading root key: %v", err)

cmd/chantools/forceclose.go

@@ -36,7 +36,7 @@ func (c *forceCloseCommand) Execute(_ []string) error {
 		extendedKey, err = hdkeychain.NewKeyFromString(c.RootKey)
 
 	default:
-		extendedKey, err = rootKeyFromConsole()
+		extendedKey, _, err = rootKeyFromConsole()
 	}
 	if err != nil {
 		return fmt.Errorf("error reading root key: %v", err)

cmd/chantools/genimportscript.go

@@ -0,0 +1,159 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcutil"
+	"github.com/btcsuite/btcutil/hdkeychain"
+	"github.com/guggero/chantools/btc"
+)
+
+const (
+	defaultRecoveryWindow = 2500
+	defaultRescanFrom     = 500000
+)
+
+type genImportScriptCommand struct {
+	RootKey        string `long:"rootkey" description:"BIP32 HD root key to use. Leave empty to prompt for lnd 24 word aezeed."`
+	Format         string `long:"format" description:"The format of the generated import script. Currently supported are: bitcoin-cli, bitcoin-cli-watchonly."`
+	RecoveryWindow uint32 `long:"recoverywindow" description:"The number of keys to scan per internal/external branch. The output will consist of double this amount of keys. (default 2500)"`
+	RescanFrom     uint32 `long:"rescanfrom" description:"The block number to rescan from. Will be set automatically from the wallet birthday if the lnd 24 word aezeed is entered. (default 500000)"`
+}
+
+func (c *genImportScriptCommand) Execute(_ []string) error {
+	var (
+		extendedKey *hdkeychain.ExtendedKey
+		err         error
+		birthday    time.Time
+	)
+
+	// Check that root key is valid or fall back to console input.
+	switch {
+	case c.RootKey != "":
+		extendedKey, err = hdkeychain.NewKeyFromString(c.RootKey)
+		if err != nil {
+			return fmt.Errorf("error reading root key: %v", err)
+		}
+
+	default:
+		extendedKey, birthday, err = rootKeyFromConsole()
+		if err != nil {
+			return fmt.Errorf("error reading root key: %v", err)
+		}
+		// The btcwallet gives the birthday a slack of 48 hours, let's
+		// do the same.
+		c.RescanFrom = seedBirthdayToBlock(birthday.Add(-48 * time.Hour))
+	}
+
+	// Set default values.
+	if c.RecoveryWindow == 0 {
+		c.RecoveryWindow = defaultRecoveryWindow
+	}
+	if c.RescanFrom == 0 {
+		c.RescanFrom = defaultRescanFrom
+	}
+
+	// Determine the format.
+	printFn := printBitcoinCli
+	if c.Format == "bitcoin-cli-watchonly" {
+		printFn = printBitcoinCliWatchOnly
+	}
+
+	fmt.Println("# Paste the following lines into a command line window.")
+
+	// External branch first (m/84'/<coinType>'/0'/0/x).
+	for i := uint32(0); i < c.RecoveryWindow; i++ {
+		derivedKey, err := btc.DeriveChildren(extendedKey, []uint32{
+			btc.HardenedKeyStart + uint32(84),
+			btc.HardenedKeyStart + chainParams.HDCoinType,
+			btc.HardenedKeyStart + uint32(0),
+			0,
+			i,
+		})
+		if err != nil {
+			return err
+		}
+		err = printFn(derivedKey, 0, i)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Now the internal branch (m/84'/<coinType>'/0'/1/x).
+	for i := uint32(0); i < c.RecoveryWindow; i++ {
+		derivedKey, err := btc.DeriveChildren(extendedKey, []uint32{
+			btc.HardenedKeyStart + uint32(84),
+			btc.HardenedKeyStart + chainParams.HDCoinType,
+			btc.HardenedKeyStart + uint32(0),
+			1,
+			i,
+		})
+		if err != nil {
+			return err
+		}
+		err = printFn(derivedKey, 1, i)
+		if err != nil {
+			return err
+		}
+	}
+
+	fmt.Printf("bitcoin-cli rescanblockchain %d\n", c.RescanFrom)
+	return nil
+}
+
+func printBitcoinCli(derivedKey *hdkeychain.ExtendedKey, branch,
+	index uint32) error {
+
+	privKey, err := derivedKey.ECPrivKey()
+	if err != nil {
+		return fmt.Errorf("could not derive private key: %v",
+			err)
+	}
+	wif, err := btcutil.NewWIF(privKey, chainParams, true)
+	if err != nil {
+		return fmt.Errorf("could not encode WIF: %v", err)
+	}
+
+	fmt.Printf("bitcoin-cli importprivkey %s \"m/84'/%d'/0'/%d/%d/"+
+		"\" false\n", wif.String(), chainParams.HDCoinType, branch,
+		index)
+	return nil
+}
+
+func printBitcoinCliWatchOnly(derivedKey *hdkeychain.ExtendedKey, branch,
+	index uint32) error {
+
+	pubKey, err := derivedKey.ECPubKey()
+	if err != nil {
+		return fmt.Errorf("could not derive private key: %v",
+			err)
+	}
+
+	fmt.Printf("bitcoin-cli importpubkey %x \"m/84'/%d'/0'/%d/%d/"+
+		"\" false\n", pubKey.SerializeCompressed(),
+		chainParams.HDCoinType, branch, index)
+	return nil
+}
+
+func seedBirthdayToBlock(birthdayTimestamp time.Time) uint32 {
+	var genesisTimestamp time.Time
+	switch chainParams.Name {
+	case "mainnet":
+		genesisTimestamp =
+			chaincfg.MainNetParams.GenesisBlock.Header.Timestamp
+
+	case "testnet":
+		genesisTimestamp =
+			chaincfg.TestNet3Params.GenesisBlock.Header.Timestamp
+
+	default:
+		panic(fmt.Errorf("unimplemented network %v", chainParams.Name))
+	}
+
+	// With the timestamps retrieved, we can estimate a block height by
+	// taking the difference between them and dividing by the average block
+	// time (10 minutes).
+	return uint32(birthdayTimestamp.Sub(genesisTimestamp).Seconds() / 600)
+}

cmd/chantools/main.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"strings"
 	"syscall"
+	"time"
 
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcutil/hdkeychain"
@@ -95,13 +96,18 @@ func runCommandParser() error {
 			"from the BIP32 HD root key.", "", &deriveKeyCommand{},
 	)
 	_, _ = parser.AddCommand(
-		"filterbackup", "Filter an lnd channel.backup file and " +
+		"filterbackup", "Filter an lnd channel.backup file and "+
 			"remove certain channels.", "", &filterBackupCommand{},
 	)
 	_, _ = parser.AddCommand(
-		"fixoldbackup", "Fixes an old channel.backup file that is " +
+		"fixoldbackup", "Fixes an old channel.backup file that is "+
-			"affected by the lnd issue #3881 (unable to derive " +
+			"affected by the lnd issue #3881 (unable to derive "+
 			"shachain root key).", "", &fixOldBackupCommand{})
+	_, _ = parser.AddCommand(
+		"genimportscript", "Generate a script containing the on-chain "+
+			"keys of an lnd wallet that can be imported into "+
+			"other software like bitcoind.", "",
+		&genImportScriptCommand{})
 
 	_, err := parser.Parse()
 	return err
@@ -158,13 +164,13 @@ func readInput(input string) ([]byte, error) {
 	return ioutil.ReadFile(input)
 }
 
-func rootKeyFromConsole() (*hdkeychain.ExtendedKey, error) {
+func rootKeyFromConsole() (*hdkeychain.ExtendedKey, time.Time, 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, err
+		return nil, time.Unix(0, 0), err
 	}
 
 	// We'll trim off extra spaces, and ensure the mnemonic is all
@@ -177,8 +183,8 @@ func rootKeyFromConsole() (*hdkeychain.ExtendedKey, error) {
 	fmt.Println()
 
 	if len(cipherSeedMnemonic) != 24 {
-		return nil, fmt.Errorf("wrong cipher seed mnemonic "+
+		return nil, time.Unix(0, 0), fmt.Errorf("wrong cipher seed "+
-			"length: got %v words, expecting %v words",
+			"mnemonic length: got %v words, expecting %v words",
 			len(cipherSeedMnemonic), 24)
 	}
 
@@ -189,7 +195,7 @@ func rootKeyFromConsole() (*hdkeychain.ExtendedKey, error) {
 		"your seed doesn't have a passphrase): ")
 	passphrase, err := terminal.ReadPassword(syscall.Stdin)
 	if err != nil {
-		return nil, err
+		return nil, time.Unix(0, 0), err
 	}
 
 	var mnemonic aezeed.Mnemonic
@@ -199,14 +205,15 @@ func rootKeyFromConsole() (*hdkeychain.ExtendedKey, error) {
 	// mnemonic is wrong, or the passphrase is wrong.
 	cipherSeed, err := mnemonic.ToCipherSeed(passphrase)
 	if err != nil {
-		return nil, fmt.Errorf("failed to decrypt seed with passphrase"+
+		return nil, time.Unix(0, 0), fmt.Errorf("failed to decrypt "+
-			": %v", err)
+			"seed with passphrase: %v", err)
 	}
 	rootKey, err := hdkeychain.NewMaster(cipherSeed.Entropy[:], chainParams)
 	if err != nil {
-		return nil, fmt.Errorf("failed to derive master extended key")
+		return nil, time.Unix(0, 0), fmt.Errorf("failed to derive " +
+			"master extended key")
 	}
-	return rootKey, nil
+	return rootKey, cipherSeed.BirthdayTime(), nil
 }
 
 func setupChainParams(cfg *config) {

cmd/chantools/rescueclosed.go

@@ -48,7 +48,7 @@ func (c *rescueClosedCommand) Execute(_ []string) error {
 		extendedKey, err = hdkeychain.NewKeyFromString(c.RootKey)
 
 	default:
-		extendedKey, err = rootKeyFromConsole()
+		extendedKey, _, err = rootKeyFromConsole()
 	}
 	if err != nil {
 		return fmt.Errorf("error reading root key: %v", err)

cmd/chantools/showrootkey.go

@@ -7,7 +7,7 @@ import (
 type showRootKeyCommand struct{}
 
 func (c *showRootKeyCommand) Execute(_ []string) error {
-	rootKey, err := rootKeyFromConsole()
+	rootKey, _, err := rootKeyFromConsole()
 	if err != nil {
 		return fmt.Errorf("failed to read root key from console: %v",
 			err)

cmd/chantools/sweeptimelock.go

@@ -38,7 +38,7 @@ func (c *sweepTimeLockCommand) Execute(_ []string) error {
 		extendedKey, err = hdkeychain.NewKeyFromString(c.RootKey)
 
 	default:
-		extendedKey, err = rootKeyFromConsole()
+		extendedKey, _, err = rootKeyFromConsole()
 	}
 	if err != nil {
 		return fmt.Errorf("error reading root key: %v", err)

dump/dump.go

@@ -3,10 +3,10 @@ package dump
 import (
 	"encoding/hex"
 	"fmt"
-	"github.com/btcsuite/btcd/chaincfg"
 	"net"
 
 	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/chanbackup"