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Diffstat (limited to 'accounts/usbwallet/ledger.go')
| -rw-r--r-- | accounts/usbwallet/ledger.go | 465 |
1 files changed, 465 insertions, 0 deletions
diff --git a/accounts/usbwallet/ledger.go b/accounts/usbwallet/ledger.go new file mode 100644 index 0000000..528e8da --- /dev/null +++ b/accounts/usbwallet/ledger.go @@ -0,0 +1,465 @@ +// Copyright 2017 The go-ethereum Authors +// This file is part of the go-ethereum library. +// +// The go-ethereum library is free software: you can redistribute it and/or modify +// it under the terms of the GNU Lesser General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// The go-ethereum library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public License +// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. + +// This file contains the implementation for interacting with the Ledger hardware +// wallets. The wire protocol spec can be found in the Ledger Blue GitHub repo: +// https://raw.githubusercontent.com/LedgerHQ/blue-app-eth/master/doc/ethapp.asc + +package usbwallet + +import ( + "encoding/binary" + "encoding/hex" + "errors" + "fmt" + "io" + "math/big" + + "github.com/ava-labs/coreth/accounts" + "github.com/ava-labs/coreth/core/types" + "github.com/ava-labs/go-ethereum/common" + "github.com/ava-labs/go-ethereum/common/hexutil" + "github.com/ava-labs/go-ethereum/crypto" + "github.com/ava-labs/go-ethereum/log" + "github.com/ava-labs/go-ethereum/rlp" +) + +// ledgerOpcode is an enumeration encoding the supported Ledger opcodes. +type ledgerOpcode byte + +// ledgerParam1 is an enumeration encoding the supported Ledger parameters for +// specific opcodes. The same parameter values may be reused between opcodes. +type ledgerParam1 byte + +// ledgerParam2 is an enumeration encoding the supported Ledger parameters for +// specific opcodes. The same parameter values may be reused between opcodes. +type ledgerParam2 byte + +const ( + ledgerOpRetrieveAddress ledgerOpcode = 0x02 // Returns the public key and Ethereum address for a given BIP 32 path + ledgerOpSignTransaction ledgerOpcode = 0x04 // Signs an Ethereum transaction after having the user validate the parameters + ledgerOpGetConfiguration ledgerOpcode = 0x06 // Returns specific wallet application configuration + + ledgerP1DirectlyFetchAddress ledgerParam1 = 0x00 // Return address directly from the wallet + ledgerP1InitTransactionData ledgerParam1 = 0x00 // First transaction data block for signing + ledgerP1ContTransactionData ledgerParam1 = 0x80 // Subsequent transaction data block for signing + ledgerP2DiscardAddressChainCode ledgerParam2 = 0x00 // Do not return the chain code along with the address +) + +// errLedgerReplyInvalidHeader is the error message returned by a Ledger data exchange +// if the device replies with a mismatching header. This usually means the device +// is in browser mode. +var errLedgerReplyInvalidHeader = errors.New("ledger: invalid reply header") + +// errLedgerInvalidVersionReply is the error message returned by a Ledger version retrieval +// when a response does arrive, but it does not contain the expected data. +var errLedgerInvalidVersionReply = errors.New("ledger: invalid version reply") + +// ledgerDriver implements the communication with a Ledger hardware wallet. +type ledgerDriver struct { + device io.ReadWriter // USB device connection to communicate through + version [3]byte // Current version of the Ledger firmware (zero if app is offline) + browser bool // Flag whether the Ledger is in browser mode (reply channel mismatch) + failure error // Any failure that would make the device unusable + log log.Logger // Contextual logger to tag the ledger with its id +} + +// newLedgerDriver creates a new instance of a Ledger USB protocol driver. +func newLedgerDriver(logger log.Logger) driver { + return &ledgerDriver{ + log: logger, + } +} + +// Status implements usbwallet.driver, returning various states the Ledger can +// currently be in. +func (w *ledgerDriver) Status() (string, error) { + if w.failure != nil { + return fmt.Sprintf("Failed: %v", w.failure), w.failure + } + if w.browser { + return "Ethereum app in browser mode", w.failure + } + if w.offline() { + return "Ethereum app offline", w.failure + } + return fmt.Sprintf("Ethereum app v%d.%d.%d online", w.version[0], w.version[1], w.version[2]), w.failure +} + +// offline returns whether the wallet and the Ethereum app is offline or not. +// +// The method assumes that the state lock is held! +func (w *ledgerDriver) offline() bool { + return w.version == [3]byte{0, 0, 0} +} + +// Open implements usbwallet.driver, attempting to initialize the connection to the +// Ledger hardware wallet. The Ledger does not require a user passphrase, so that +// parameter is silently discarded. +func (w *ledgerDriver) Open(device io.ReadWriter, passphrase string) error { + w.device, w.failure = device, nil + + _, err := w.ledgerDerive(accounts.DefaultBaseDerivationPath) + if err != nil { + // Ethereum app is not running or in browser mode, nothing more to do, return + if err == errLedgerReplyInvalidHeader { + w.browser = true + } + return nil + } + // Try to resolve the Ethereum app's version, will fail prior to v1.0.2 + if w.version, err = w.ledgerVersion(); err != nil { + w.version = [3]byte{1, 0, 0} // Assume worst case, can't verify if v1.0.0 or v1.0.1 + } + return nil +} + +// Close implements usbwallet.driver, cleaning up and metadata maintained within +// the Ledger driver. +func (w *ledgerDriver) Close() error { + w.browser, w.version = false, [3]byte{} + return nil +} + +// Heartbeat implements usbwallet.driver, performing a sanity check against the +// Ledger to see if it's still online. +func (w *ledgerDriver) Heartbeat() error { + if _, err := w.ledgerVersion(); err != nil && err != errLedgerInvalidVersionReply { + w.failure = err + return err + } + return nil +} + +// Derive implements usbwallet.driver, sending a derivation request to the Ledger +// and returning the Ethereum address located on that derivation path. +func (w *ledgerDriver) Derive(path accounts.DerivationPath) (common.Address, error) { + return w.ledgerDerive(path) +} + +// SignTx implements usbwallet.driver, sending the transaction to the Ledger and +// waiting for the user to confirm or deny the transaction. +// +// Note, if the version of the Ethereum application running on the Ledger wallet is +// too old to sign EIP-155 transactions, but such is requested nonetheless, an error +// will be returned opposed to silently signing in Homestead mode. +func (w *ledgerDriver) SignTx(path accounts.DerivationPath, tx *types.Transaction, chainID *big.Int) (common.Address, *types.Transaction, error) { + // If the Ethereum app doesn't run, abort + if w.offline() { + return common.Address{}, nil, accounts.ErrWalletClosed + } + // Ensure the wallet is capable of signing the given transaction + if chainID != nil && w.version[0] <= 1 && w.version[1] <= 0 && w.version[2] <= 2 { + return common.Address{}, nil, fmt.Errorf("Ledger v%d.%d.%d doesn't support signing this transaction, please update to v1.0.3 at least", w.version[0], w.version[1], w.version[2]) + } + // All infos gathered and metadata checks out, request signing + return w.ledgerSign(path, tx, chainID) +} + +// ledgerVersion retrieves the current version of the Ethereum wallet app running +// on the Ledger wallet. +// +// The version retrieval protocol is defined as follows: +// +// CLA | INS | P1 | P2 | Lc | Le +// ----+-----+----+----+----+--- +// E0 | 06 | 00 | 00 | 00 | 04 +// +// With no input data, and the output data being: +// +// Description | Length +// ---------------------------------------------------+-------- +// Flags 01: arbitrary data signature enabled by user | 1 byte +// Application major version | 1 byte +// Application minor version | 1 byte +// Application patch version | 1 byte +func (w *ledgerDriver) ledgerVersion() ([3]byte, error) { + // Send the request and wait for the response + reply, err := w.ledgerExchange(ledgerOpGetConfiguration, 0, 0, nil) + if err != nil { + return [3]byte{}, err + } + if len(reply) != 4 { + return [3]byte{}, errLedgerInvalidVersionReply + } + // Cache the version for future reference + var version [3]byte + copy(version[:], reply[1:]) + return version, nil +} + +// ledgerDerive retrieves the currently active Ethereum address from a Ledger +// wallet at the specified derivation path. +// +// The address derivation protocol is defined as follows: +// +// CLA | INS | P1 | P2 | Lc | Le +// ----+-----+----+----+-----+--- +// E0 | 02 | 00 return address +// 01 display address and confirm before returning +// | 00: do not return the chain code +// | 01: return the chain code +// | var | 00 +// +// Where the input data is: +// +// Description | Length +// -------------------------------------------------+-------- +// Number of BIP 32 derivations to perform (max 10) | 1 byte +// First derivation index (big endian) | 4 bytes +// ... | 4 bytes +// Last derivation index (big endian) | 4 bytes +// +// And the output data is: +// +// Description | Length +// ------------------------+------------------- +// Public Key length | 1 byte +// Uncompressed Public Key | arbitrary +// Ethereum address length | 1 byte +// Ethereum address | 40 bytes hex ascii +// Chain code if requested | 32 bytes +func (w *ledgerDriver) ledgerDerive(derivationPath []uint32) (common.Address, error) { + // Flatten the derivation path into the Ledger request + path := make([]byte, 1+4*len(derivationPath)) + path[0] = byte(len(derivationPath)) + for i, component := range derivationPath { + binary.BigEndian.PutUint32(path[1+4*i:], component) + } + // Send the request and wait for the response + reply, err := w.ledgerExchange(ledgerOpRetrieveAddress, ledgerP1DirectlyFetchAddress, ledgerP2DiscardAddressChainCode, path) + if err != nil { + return common.Address{}, err + } + // Discard the public key, we don't need that for now + if len(reply) < 1 || len(reply) < 1+int(reply[0]) { + return common.Address{}, errors.New("reply lacks public key entry") + } + reply = reply[1+int(reply[0]):] + + // Extract the Ethereum hex address string + if len(reply) < 1 || len(reply) < 1+int(reply[0]) { + return common.Address{}, errors.New("reply lacks address entry") + } + hexstr := reply[1 : 1+int(reply[0])] + + // Decode the hex sting into an Ethereum address and return + var address common.Address + if _, err = hex.Decode(address[:], hexstr); err != nil { + return common.Address{}, err + } + return address, nil +} + +// ledgerSign sends the transaction to the Ledger wallet, and waits for the user +// to confirm or deny the transaction. +// +// The transaction signing protocol is defined as follows: +// +// CLA | INS | P1 | P2 | Lc | Le +// ----+-----+----+----+-----+--- +// E0 | 04 | 00: first transaction data block +// 80: subsequent transaction data block +// | 00 | variable | variable +// +// Where the input for the first transaction block (first 255 bytes) is: +// +// Description | Length +// -------------------------------------------------+---------- +// Number of BIP 32 derivations to perform (max 10) | 1 byte +// First derivation index (big endian) | 4 bytes +// ... | 4 bytes +// Last derivation index (big endian) | 4 bytes +// RLP transaction chunk | arbitrary +// +// And the input for subsequent transaction blocks (first 255 bytes) are: +// +// Description | Length +// ----------------------+---------- +// RLP transaction chunk | arbitrary +// +// And the output data is: +// +// Description | Length +// ------------+--------- +// signature V | 1 byte +// signature R | 32 bytes +// signature S | 32 bytes +func (w *ledgerDriver) ledgerSign(derivationPath []uint32, tx *types.Transaction, chainID *big.Int) (common.Address, *types.Transaction, error) { + // Flatten the derivation path into the Ledger request + path := make([]byte, 1+4*len(derivationPath)) + path[0] = byte(len(derivationPath)) + for i, component := range derivationPath { + binary.BigEndian.PutUint32(path[1+4*i:], component) + } + // Create the transaction RLP based on whether legacy or EIP155 signing was requested + var ( + txrlp []byte + err error + ) + if chainID == nil { + if txrlp, err = rlp.EncodeToBytes([]interface{}{tx.Nonce(), tx.GasPrice(), tx.Gas(), tx.To(), tx.Value(), tx.Data()}); err != nil { + return common.Address{}, nil, err + } + } else { + if txrlp, err = rlp.EncodeToBytes([]interface{}{tx.Nonce(), tx.GasPrice(), tx.Gas(), tx.To(), tx.Value(), tx.Data(), chainID, big.NewInt(0), big.NewInt(0)}); err != nil { + return common.Address{}, nil, err + } + } + payload := append(path, txrlp...) + + // Send the request and wait for the response + var ( + op = ledgerP1InitTransactionData + reply []byte + ) + for len(payload) > 0 { + // Calculate the size of the next data chunk + chunk := 255 + if chunk > len(payload) { + chunk = len(payload) + } + // Send the chunk over, ensuring it's processed correctly + reply, err = w.ledgerExchange(ledgerOpSignTransaction, op, 0, payload[:chunk]) + if err != nil { + return common.Address{}, nil, err + } + // Shift the payload and ensure subsequent chunks are marked as such + payload = payload[chunk:] + op = ledgerP1ContTransactionData + } + // Extract the Ethereum signature and do a sanity validation + if len(reply) != crypto.SignatureLength { + return common.Address{}, nil, errors.New("reply lacks signature") + } + signature := append(reply[1:], reply[0]) + + // Create the correct signer and signature transform based on the chain ID + var signer types.Signer + if chainID == nil { + signer = new(types.HomesteadSigner) + } else { + signer = types.NewEIP155Signer(chainID) + signature[64] -= byte(chainID.Uint64()*2 + 35) + } + signed, err := tx.WithSignature(signer, signature) + if err != nil { + return common.Address{}, nil, err + } + sender, err := types.Sender(signer, signed) + if err != nil { + return common.Address{}, nil, err + } + return sender, signed, nil +} + +// ledgerExchange performs a data exchange with the Ledger wallet, sending it a +// message and retrieving the response. +// +// The common transport header is defined as follows: +// +// Description | Length +// --------------------------------------+---------- +// Communication channel ID (big endian) | 2 bytes +// Command tag | 1 byte +// Packet sequence index (big endian) | 2 bytes +// Payload | arbitrary +// +// The Communication channel ID allows commands multiplexing over the same +// physical link. It is not used for the time being, and should be set to 0101 +// to avoid compatibility issues with implementations ignoring a leading 00 byte. +// +// The Command tag describes the message content. Use TAG_APDU (0x05) for standard +// APDU payloads, or TAG_PING (0x02) for a simple link test. +// +// The Packet sequence index describes the current sequence for fragmented payloads. +// The first fragment index is 0x00. +// +// APDU Command payloads are encoded as follows: +// +// Description | Length +// ----------------------------------- +// APDU length (big endian) | 2 bytes +// APDU CLA | 1 byte +// APDU INS | 1 byte +// APDU P1 | 1 byte +// APDU P2 | 1 byte +// APDU length | 1 byte +// Optional APDU data | arbitrary +func (w *ledgerDriver) ledgerExchange(opcode ledgerOpcode, p1 ledgerParam1, p2 ledgerParam2, data []byte) ([]byte, error) { + // Construct the message payload, possibly split into multiple chunks + apdu := make([]byte, 2, 7+len(data)) + + binary.BigEndian.PutUint16(apdu, uint16(5+len(data))) + apdu = append(apdu, []byte{0xe0, byte(opcode), byte(p1), byte(p2), byte(len(data))}...) + apdu = append(apdu, data...) + + // Stream all the chunks to the device + header := []byte{0x01, 0x01, 0x05, 0x00, 0x00} // Channel ID and command tag appended + chunk := make([]byte, 64) + space := len(chunk) - len(header) + + for i := 0; len(apdu) > 0; i++ { + // Construct the new message to stream + chunk = append(chunk[:0], header...) + binary.BigEndian.PutUint16(chunk[3:], uint16(i)) + + if len(apdu) > space { + chunk = append(chunk, apdu[:space]...) + apdu = apdu[space:] + } else { + chunk = append(chunk, apdu...) + apdu = nil + } + // Send over to the device + w.log.Trace("Data chunk sent to the Ledger", "chunk", hexutil.Bytes(chunk)) + if _, err := w.device.Write(chunk); err != nil { + return nil, err + } + } + // Stream the reply back from the wallet in 64 byte chunks + var reply []byte + chunk = chunk[:64] // Yeah, we surely have enough space + for { + // Read the next chunk from the Ledger wallet + if _, err := io.ReadFull(w.device, chunk); err != nil { + return nil, err + } + w.log.Trace("Data chunk received from the Ledger", "chunk", hexutil.Bytes(chunk)) + + // Make sure the transport header matches + if chunk[0] != 0x01 || chunk[1] != 0x01 || chunk[2] != 0x05 { + return nil, errLedgerReplyInvalidHeader + } + // If it's the first chunk, retrieve the total message length + var payload []byte + + if chunk[3] == 0x00 && chunk[4] == 0x00 { + reply = make([]byte, 0, int(binary.BigEndian.Uint16(chunk[5:7]))) + payload = chunk[7:] + } else { + payload = chunk[5:] + } + // Append to the reply and stop when filled up + if left := cap(reply) - len(reply); left > len(payload) { + reply = append(reply, payload...) + } else { + reply = append(reply, payload[:left]...) + break + } + } + return reply[:len(reply)-2], nil +} |