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Diffstat (limited to 'accounts/scwallet/wallet.go')
| -rw-r--r-- | accounts/scwallet/wallet.go | 1082 |
1 files changed, 1082 insertions, 0 deletions
diff --git a/accounts/scwallet/wallet.go b/accounts/scwallet/wallet.go new file mode 100644 index 0000000..f72e685 --- /dev/null +++ b/accounts/scwallet/wallet.go @@ -0,0 +1,1082 @@ +// Copyright 2018 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/>. + +package scwallet + +import ( + "bytes" + "context" + "crypto/hmac" + "crypto/sha256" + "crypto/sha512" + "encoding/asn1" + "encoding/binary" + "errors" + "fmt" + "math/big" + "regexp" + "sort" + "strings" + "sync" + "time" + + "github.com/ava-labs/coreth/accounts" + "github.com/ava-labs/coreth/core/types" + ethereum "github.com/ava-labs/go-ethereum" + "github.com/ava-labs/go-ethereum/common" + "github.com/ava-labs/go-ethereum/crypto" + "github.com/ava-labs/go-ethereum/log" + pcsc "github.com/gballet/go-libpcsclite" + "github.com/status-im/keycard-go/derivationpath" +) + +// ErrPairingPasswordNeeded is returned if opening the smart card requires pairing with a pairing +// password. In this case, the calling application should request user input to enter +// the pairing password and send it back. +var ErrPairingPasswordNeeded = errors.New("smartcard: pairing password needed") + +// ErrPINNeeded is returned if opening the smart card requires a PIN code. In +// this case, the calling application should request user input to enter the PIN +// and send it back. +var ErrPINNeeded = errors.New("smartcard: pin needed") + +// ErrPINUnblockNeeded is returned if opening the smart card requires a PIN code, +// but all PIN attempts have already been exhausted. In this case the calling +// application should request user input for the PUK and a new PIN code to set +// fo the card. +var ErrPINUnblockNeeded = errors.New("smartcard: pin unblock needed") + +// ErrAlreadyOpen is returned if the smart card is attempted to be opened, but +// there is already a paired and unlocked session. +var ErrAlreadyOpen = errors.New("smartcard: already open") + +// ErrPubkeyMismatch is returned if the public key recovered from a signature +// does not match the one expected by the user. +var ErrPubkeyMismatch = errors.New("smartcard: recovered public key mismatch") + +var ( + appletAID = []byte{0xA0, 0x00, 0x00, 0x08, 0x04, 0x00, 0x01, 0x01, 0x01} + // DerivationSignatureHash is used to derive the public key from the signature of this hash + DerivationSignatureHash = sha256.Sum256(common.Hash{}.Bytes()) +) + +// List of APDU command-related constants +const ( + claISO7816 = 0 + claSCWallet = 0x80 + + insSelect = 0xA4 + insGetResponse = 0xC0 + sw1GetResponse = 0x61 + sw1Ok = 0x90 + + insVerifyPin = 0x20 + insUnblockPin = 0x22 + insExportKey = 0xC2 + insSign = 0xC0 + insLoadKey = 0xD0 + insDeriveKey = 0xD1 + insStatus = 0xF2 +) + +// List of ADPU command parameters +const ( + P1DeriveKeyFromMaster = uint8(0x00) + P1DeriveKeyFromParent = uint8(0x01) + P1DeriveKeyFromCurrent = uint8(0x10) + statusP1WalletStatus = uint8(0x00) + statusP1Path = uint8(0x01) + signP1PrecomputedHash = uint8(0x01) + signP2OnlyBlock = uint8(0x81) + exportP1Any = uint8(0x00) + exportP2Pubkey = uint8(0x01) +) + +// Minimum time to wait between self derivation attempts, even it the user is +// requesting accounts like crazy. +const selfDeriveThrottling = time.Second + +// Wallet represents a smartcard wallet instance. +type Wallet struct { + Hub *Hub // A handle to the Hub that instantiated this wallet. + PublicKey []byte // The wallet's public key (used for communication and identification, not signing!) + + lock sync.Mutex // Lock that gates access to struct fields and communication with the card + card *pcsc.Card // A handle to the smartcard interface for the wallet. + session *Session // The secure communication session with the card + log log.Logger // Contextual logger to tag the base with its id + + deriveNextPaths []accounts.DerivationPath // Next derivation paths for account auto-discovery (multiple bases supported) + deriveNextAddrs []common.Address // Next derived account addresses for auto-discovery (multiple bases supported) + deriveChain ethereum.ChainStateReader // Blockchain state reader to discover used account with + deriveReq chan chan struct{} // Channel to request a self-derivation on + deriveQuit chan chan error // Channel to terminate the self-deriver with +} + +// NewWallet constructs and returns a new Wallet instance. +func NewWallet(hub *Hub, card *pcsc.Card) *Wallet { + wallet := &Wallet{ + Hub: hub, + card: card, + } + return wallet +} + +// transmit sends an APDU to the smartcard and receives and decodes the response. +// It automatically handles requests by the card to fetch the return data separately, +// and returns an error if the response status code is not success. +func transmit(card *pcsc.Card, command *commandAPDU) (*responseAPDU, error) { + data, err := command.serialize() + if err != nil { + return nil, err + } + + responseData, _, err := card.Transmit(data) + if err != nil { + return nil, err + } + + response := new(responseAPDU) + if err = response.deserialize(responseData); err != nil { + return nil, err + } + + // Are we being asked to fetch the response separately? + if response.Sw1 == sw1GetResponse && (command.Cla != claISO7816 || command.Ins != insGetResponse) { + return transmit(card, &commandAPDU{ + Cla: claISO7816, + Ins: insGetResponse, + P1: 0, + P2: 0, + Data: nil, + Le: response.Sw2, + }) + } + + if response.Sw1 != sw1Ok { + return nil, fmt.Errorf("Unexpected insecure response status Cla=0x%x, Ins=0x%x, Sw=0x%x%x", command.Cla, command.Ins, response.Sw1, response.Sw2) + } + + return response, nil +} + +// applicationInfo encodes information about the smartcard application - its +// instance UID and public key. +type applicationInfo struct { + InstanceUID []byte `asn1:"tag:15"` + PublicKey []byte `asn1:"tag:0"` +} + +// connect connects to the wallet application and establishes a secure channel with it. +// must be called before any other interaction with the wallet. +func (w *Wallet) connect() error { + w.lock.Lock() + defer w.lock.Unlock() + + appinfo, err := w.doselect() + if err != nil { + return err + } + + channel, err := NewSecureChannelSession(w.card, appinfo.PublicKey) + if err != nil { + return err + } + + w.PublicKey = appinfo.PublicKey + w.log = log.New("url", w.URL()) + w.session = &Session{ + Wallet: w, + Channel: channel, + } + return nil +} + +// doselect is an internal (unlocked) function to send a SELECT APDU to the card. +func (w *Wallet) doselect() (*applicationInfo, error) { + response, err := transmit(w.card, &commandAPDU{ + Cla: claISO7816, + Ins: insSelect, + P1: 4, + P2: 0, + Data: appletAID, + }) + if err != nil { + return nil, err + } + + appinfo := new(applicationInfo) + if _, err := asn1.UnmarshalWithParams(response.Data, appinfo, "tag:4"); err != nil { + return nil, err + } + return appinfo, nil +} + +// ping checks the card's status and returns an error if unsuccessful. +func (w *Wallet) ping() error { + w.lock.Lock() + defer w.lock.Unlock() + + // We can't ping if not paired + if !w.session.paired() { + return nil + } + if _, err := w.session.walletStatus(); err != nil { + return err + } + return nil +} + +// release releases any resources held by an open wallet instance. +func (w *Wallet) release() error { + if w.session != nil { + return w.session.release() + } + return nil +} + +// pair is an internal (unlocked) function for establishing a new pairing +// with the wallet. +func (w *Wallet) pair(puk []byte) error { + if w.session.paired() { + return fmt.Errorf("Wallet already paired") + } + pairing, err := w.session.pair(puk) + if err != nil { + return err + } + if err = w.Hub.setPairing(w, &pairing); err != nil { + return err + } + return w.session.authenticate(pairing) +} + +// Unpair deletes an existing wallet pairing. +func (w *Wallet) Unpair(pin []byte) error { + w.lock.Lock() + defer w.lock.Unlock() + + if !w.session.paired() { + return fmt.Errorf("wallet %x not paired", w.PublicKey) + } + if err := w.session.verifyPin(pin); err != nil { + return fmt.Errorf("failed to verify pin: %s", err) + } + if err := w.session.unpair(); err != nil { + return fmt.Errorf("failed to unpair: %s", err) + } + if err := w.Hub.setPairing(w, nil); err != nil { + return err + } + return nil +} + +// URL retrieves the canonical path under which this wallet is reachable. It is +// user by upper layers to define a sorting order over all wallets from multiple +// backends. +func (w *Wallet) URL() accounts.URL { + return accounts.URL{ + Scheme: w.Hub.scheme, + Path: fmt.Sprintf("%x", w.PublicKey[1:5]), // Byte #0 isn't unique; 1:5 covers << 64K cards, bump to 1:9 for << 4M + } +} + +// Status returns a textual status to aid the user in the current state of the +// wallet. It also returns an error indicating any failure the wallet might have +// encountered. +func (w *Wallet) Status() (string, error) { + w.lock.Lock() + defer w.lock.Unlock() + + // If the card is not paired, we can only wait + if !w.session.paired() { + return "Unpaired, waiting for pairing password", nil + } + // Yay, we have an encrypted session, retrieve the actual status + status, err := w.session.walletStatus() + if err != nil { + return fmt.Sprintf("Failed: %v", err), err + } + switch { + case !w.session.verified && status.PinRetryCount == 0 && status.PukRetryCount == 0: + return fmt.Sprintf("Bricked, waiting for full wipe"), nil + case !w.session.verified && status.PinRetryCount == 0: + return fmt.Sprintf("Blocked, waiting for PUK (%d attempts left) and new PIN", status.PukRetryCount), nil + case !w.session.verified: + return fmt.Sprintf("Locked, waiting for PIN (%d attempts left)", status.PinRetryCount), nil + case !status.Initialized: + return fmt.Sprintf("Empty, waiting for initialization"), nil + default: + return fmt.Sprintf("Online"), nil + } +} + +// Open initializes access to a wallet instance. It is not meant to unlock or +// decrypt account keys, rather simply to establish a connection to hardware +// wallets and/or to access derivation seeds. +// +// The passphrase parameter may or may not be used by the implementation of a +// particular wallet instance. The reason there is no passwordless open method +// is to strive towards a uniform wallet handling, oblivious to the different +// backend providers. +// +// Please note, if you open a wallet, you must close it to release any allocated +// resources (especially important when working with hardware wallets). +func (w *Wallet) Open(passphrase string) error { + w.lock.Lock() + defer w.lock.Unlock() + + // If the session is already open, bail out + if w.session.verified { + return ErrAlreadyOpen + } + // If the smart card is not yet paired, attempt to do so either from a previous + // pairing key or form the supplied PUK code. + if !w.session.paired() { + // If a previous pairing exists, only ever try to use that + if pairing := w.Hub.pairing(w); pairing != nil { + if err := w.session.authenticate(*pairing); err != nil { + return fmt.Errorf("failed to authenticate card %x: %s", w.PublicKey[:4], err) + } + // Pairing still ok, fall through to PIN checks + } else { + // If no passphrase was supplied, request the PUK from the user + if passphrase == "" { + return ErrPairingPasswordNeeded + } + // Attempt to pair the smart card with the user supplied PUK + if err := w.pair([]byte(passphrase)); err != nil { + return err + } + // Pairing succeeded, fall through to PIN checks. This will of course fail, + // but we can't return ErrPINNeeded directly here becase we don't know whether + // a PIN check or a PIN reset is needed. + passphrase = "" + } + } + // The smart card was successfully paired, retrieve its status to check whether + // PIN verification or unblocking is needed. + status, err := w.session.walletStatus() + if err != nil { + return err + } + // Request the appropriate next authentication data, or use the one supplied + switch { + case passphrase == "" && status.PinRetryCount > 0: + return ErrPINNeeded + case passphrase == "": + return ErrPINUnblockNeeded + case status.PinRetryCount > 0: + if !regexp.MustCompile(`^[0-9]{6,}$`).MatchString(passphrase) { + w.log.Error("PIN needs to be at least 6 digits") + return ErrPINNeeded + } + if err := w.session.verifyPin([]byte(passphrase)); err != nil { + return err + } + default: + if !regexp.MustCompile(`^[0-9]{12,}$`).MatchString(passphrase) { + w.log.Error("PUK needs to be at least 12 digits") + return ErrPINUnblockNeeded + } + if err := w.session.unblockPin([]byte(passphrase)); err != nil { + return err + } + } + // Smart card paired and unlocked, initialize and register + w.deriveReq = make(chan chan struct{}) + w.deriveQuit = make(chan chan error) + + go w.selfDerive() + + // Notify anyone listening for wallet events that a new device is accessible + go w.Hub.updateFeed.Send(accounts.WalletEvent{Wallet: w, Kind: accounts.WalletOpened}) + + return nil +} + +// Close stops and closes the wallet, freeing any resources. +func (w *Wallet) Close() error { + // Ensure the wallet was opened + w.lock.Lock() + dQuit := w.deriveQuit + w.lock.Unlock() + + // Terminate the self-derivations + var derr error + if dQuit != nil { + errc := make(chan error) + dQuit <- errc + derr = <-errc // Save for later, we *must* close the USB + } + // Terminate the device connection + w.lock.Lock() + defer w.lock.Unlock() + + w.deriveQuit = nil + w.deriveReq = nil + + if err := w.release(); err != nil { + return err + } + return derr +} + +// selfDerive is an account derivation loop that upon request attempts to find +// new non-zero accounts. +func (w *Wallet) selfDerive() { + w.log.Debug("Smart card wallet self-derivation started") + defer w.log.Debug("Smart card wallet self-derivation stopped") + + // Execute self-derivations until termination or error + var ( + reqc chan struct{} + errc chan error + err error + ) + for errc == nil && err == nil { + // Wait until either derivation or termination is requested + select { + case errc = <-w.deriveQuit: + // Termination requested + continue + case reqc = <-w.deriveReq: + // Account discovery requested + } + // Derivation needs a chain and device access, skip if either unavailable + w.lock.Lock() + if w.session == nil || w.deriveChain == nil { + w.lock.Unlock() + reqc <- struct{}{} + continue + } + pairing := w.Hub.pairing(w) + + // Device lock obtained, derive the next batch of accounts + var ( + paths []accounts.DerivationPath + nextAcc accounts.Account + + nextPaths = append([]accounts.DerivationPath{}, w.deriveNextPaths...) + nextAddrs = append([]common.Address{}, w.deriveNextAddrs...) + + context = context.Background() + ) + for i := 0; i < len(nextAddrs); i++ { + for empty := false; !empty; { + // Retrieve the next derived Ethereum account + if nextAddrs[i] == (common.Address{}) { + if nextAcc, err = w.session.derive(nextPaths[i]); err != nil { + w.log.Warn("Smartcard wallet account derivation failed", "err", err) + break + } + nextAddrs[i] = nextAcc.Address + } + // Check the account's status against the current chain state + var ( + balance *big.Int + nonce uint64 + ) + balance, err = w.deriveChain.BalanceAt(context, nextAddrs[i], nil) + if err != nil { + w.log.Warn("Smartcard wallet balance retrieval failed", "err", err) + break + } + nonce, err = w.deriveChain.NonceAt(context, nextAddrs[i], nil) + if err != nil { + w.log.Warn("Smartcard wallet nonce retrieval failed", "err", err) + break + } + // If the next account is empty, stop self-derivation, but add for the last base path + if balance.Sign() == 0 && nonce == 0 { + empty = true + if i < len(nextAddrs)-1 { + break + } + } + // We've just self-derived a new account, start tracking it locally + path := make(accounts.DerivationPath, len(nextPaths[i])) + copy(path[:], nextPaths[i][:]) + paths = append(paths, path) + + // Display a log message to the user for new (or previously empty accounts) + if _, known := pairing.Accounts[nextAddrs[i]]; !known || !empty || nextAddrs[i] != w.deriveNextAddrs[i] { + w.log.Info("Smartcard wallet discovered new account", "address", nextAddrs[i], "path", path, "balance", balance, "nonce", nonce) + } + pairing.Accounts[nextAddrs[i]] = path + + // Fetch the next potential account + if !empty { + nextAddrs[i] = common.Address{} + nextPaths[i][len(nextPaths[i])-1]++ + } + } + } + // If there are new accounts, write them out + if len(paths) > 0 { + err = w.Hub.setPairing(w, pairing) + } + // Shift the self-derivation forward + w.deriveNextAddrs = nextAddrs + w.deriveNextPaths = nextPaths + + // Self derivation complete, release device lock + w.lock.Unlock() + + // Notify the user of termination and loop after a bit of time (to avoid trashing) + reqc <- struct{}{} + if err == nil { + select { + case errc = <-w.deriveQuit: + // Termination requested, abort + case <-time.After(selfDeriveThrottling): + // Waited enough, willing to self-derive again + } + } + } + // In case of error, wait for termination + if err != nil { + w.log.Debug("Smartcard wallet self-derivation failed", "err", err) + errc = <-w.deriveQuit + } + errc <- err +} + +// Accounts retrieves the list of signing accounts the wallet is currently aware +// of. For hierarchical deterministic wallets, the list will not be exhaustive, +// rather only contain the accounts explicitly pinned during account derivation. +func (w *Wallet) Accounts() []accounts.Account { + // Attempt self-derivation if it's running + reqc := make(chan struct{}, 1) + select { + case w.deriveReq <- reqc: + // Self-derivation request accepted, wait for it + <-reqc + default: + // Self-derivation offline, throttled or busy, skip + } + + w.lock.Lock() + defer w.lock.Unlock() + + if pairing := w.Hub.pairing(w); pairing != nil { + ret := make([]accounts.Account, 0, len(pairing.Accounts)) + for address, path := range pairing.Accounts { + ret = append(ret, w.makeAccount(address, path)) + } + sort.Sort(accounts.AccountsByURL(ret)) + return ret + } + return nil +} + +func (w *Wallet) makeAccount(address common.Address, path accounts.DerivationPath) accounts.Account { + return accounts.Account{ + Address: address, + URL: accounts.URL{ + Scheme: w.Hub.scheme, + Path: fmt.Sprintf("%x/%s", w.PublicKey[1:3], path.String()), + }, + } +} + +// Contains returns whether an account is part of this particular wallet or not. +func (w *Wallet) Contains(account accounts.Account) bool { + if pairing := w.Hub.pairing(w); pairing != nil { + _, ok := pairing.Accounts[account.Address] + return ok + } + return false +} + +// Initialize installs a keypair generated from the provided key into the wallet. +func (w *Wallet) Initialize(seed []byte) error { + go w.selfDerive() + // DO NOT lock at this stage, as the initialize + // function relies on Status() + return w.session.initialize(seed) +} + +// Derive attempts to explicitly derive a hierarchical deterministic account at +// the specified derivation path. If requested, the derived account will be added +// to the wallet's tracked account list. +func (w *Wallet) Derive(path accounts.DerivationPath, pin bool) (accounts.Account, error) { + w.lock.Lock() + defer w.lock.Unlock() + + account, err := w.session.derive(path) + if err != nil { + return accounts.Account{}, err + } + + if pin { + pairing := w.Hub.pairing(w) + pairing.Accounts[account.Address] = path + if err := w.Hub.setPairing(w, pairing); err != nil { + return accounts.Account{}, err + } + } + + return account, nil +} + +// SelfDerive sets a base account derivation path from which the wallet attempts +// to discover non zero accounts and automatically add them to list of tracked +// accounts. +// +// Note, self derivaton will increment the last component of the specified path +// opposed to decending into a child path to allow discovering accounts starting +// from non zero components. +// +// Some hardware wallets switched derivation paths through their evolution, so +// this method supports providing multiple bases to discover old user accounts +// too. Only the last base will be used to derive the next empty account. +// +// You can disable automatic account discovery by calling SelfDerive with a nil +// chain state reader. +func (w *Wallet) SelfDerive(bases []accounts.DerivationPath, chain ethereum.ChainStateReader) { + w.lock.Lock() + defer w.lock.Unlock() + + w.deriveNextPaths = make([]accounts.DerivationPath, len(bases)) + for i, base := range bases { + w.deriveNextPaths[i] = make(accounts.DerivationPath, len(base)) + copy(w.deriveNextPaths[i][:], base[:]) + } + w.deriveNextAddrs = make([]common.Address, len(bases)) + w.deriveChain = chain +} + +// SignData requests the wallet to sign the hash of the given data. +// +// It looks up the account specified either solely via its address contained within, +// or optionally with the aid of any location metadata from the embedded URL field. +// +// If the wallet requires additional authentication to sign the request (e.g. +// a password to decrypt the account, or a PIN code o verify the transaction), +// an AuthNeededError instance will be returned, containing infos for the user +// about which fields or actions are needed. The user may retry by providing +// the needed details via SignDataWithPassphrase, or by other means (e.g. unlock +// the account in a keystore). +func (w *Wallet) SignData(account accounts.Account, mimeType string, data []byte) ([]byte, error) { + return w.signHash(account, crypto.Keccak256(data)) +} + +func (w *Wallet) signHash(account accounts.Account, hash []byte) ([]byte, error) { + w.lock.Lock() + defer w.lock.Unlock() + + path, err := w.findAccountPath(account) + if err != nil { + return nil, err + } + + return w.session.sign(path, hash) +} + +// SignTx requests the wallet to sign the given transaction. +// +// It looks up the account specified either solely via its address contained within, +// or optionally with the aid of any location metadata from the embedded URL field. +// +// If the wallet requires additional authentication to sign the request (e.g. +// a password to decrypt the account, or a PIN code o verify the transaction), +// an AuthNeededError instance will be returned, containing infos for the user +// about which fields or actions are needed. The user may retry by providing +// the needed details via SignTxWithPassphrase, or by other means (e.g. unlock +// the account in a keystore). +func (w *Wallet) SignTx(account accounts.Account, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) { + signer := types.NewEIP155Signer(chainID) + hash := signer.Hash(tx) + sig, err := w.signHash(account, hash[:]) + if err != nil { + return nil, err + } + return tx.WithSignature(signer, sig) +} + +// SignDataWithPassphrase requests the wallet to sign the given hash with the +// given passphrase as extra authentication information. +// +// It looks up the account specified either solely via its address contained within, +// or optionally with the aid of any location metadata from the embedded URL field. +func (w *Wallet) SignDataWithPassphrase(account accounts.Account, passphrase, mimeType string, data []byte) ([]byte, error) { + return w.signHashWithPassphrase(account, passphrase, crypto.Keccak256(data)) +} + +func (w *Wallet) signHashWithPassphrase(account accounts.Account, passphrase string, hash []byte) ([]byte, error) { + if !w.session.verified { + if err := w.Open(passphrase); err != nil { + return nil, err + } + } + + return w.signHash(account, hash) +} + +// SignText requests the wallet to sign the hash of a given piece of data, prefixed +// by the Ethereum prefix scheme +// It looks up the account specified either solely via its address contained within, +// or optionally with the aid of any location metadata from the embedded URL field. +// +// If the wallet requires additional authentication to sign the request (e.g. +// a password to decrypt the account, or a PIN code o verify the transaction), +// an AuthNeededError instance will be returned, containing infos for the user +// about which fields or actions are needed. The user may retry by providing +// the needed details via SignHashWithPassphrase, or by other means (e.g. unlock +// the account in a keystore). +func (w *Wallet) SignText(account accounts.Account, text []byte) ([]byte, error) { + return w.signHash(account, accounts.TextHash(text)) +} + +// SignTextWithPassphrase implements accounts.Wallet, attempting to sign the +// given hash with the given account using passphrase as extra authentication +func (w *Wallet) SignTextWithPassphrase(account accounts.Account, passphrase string, text []byte) ([]byte, error) { + return w.signHashWithPassphrase(account, passphrase, crypto.Keccak256(accounts.TextHash(text))) +} + +// SignTxWithPassphrase requests the wallet to sign the given transaction, with the +// given passphrase as extra authentication information. +// +// It looks up the account specified either solely via its address contained within, +// or optionally with the aid of any location metadata from the embedded URL field. +func (w *Wallet) SignTxWithPassphrase(account accounts.Account, passphrase string, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) { + if !w.session.verified { + if err := w.Open(passphrase); err != nil { + return nil, err + } + } + return w.SignTx(account, tx, chainID) +} + +// findAccountPath returns the derivation path for the provided account. +// It first checks for the address in the list of pinned accounts, and if it is +// not found, attempts to parse the derivation path from the account's URL. +func (w *Wallet) findAccountPath(account accounts.Account) (accounts.DerivationPath, error) { + pairing := w.Hub.pairing(w) + if path, ok := pairing.Accounts[account.Address]; ok { + return path, nil + } + + // Look for the path in the URL + if account.URL.Scheme != w.Hub.scheme { + return nil, fmt.Errorf("Scheme %s does not match wallet scheme %s", account.URL.Scheme, w.Hub.scheme) + } + + parts := strings.SplitN(account.URL.Path, "/", 2) + if len(parts) != 2 { + return nil, fmt.Errorf("Invalid URL format: %s", account.URL) + } + + if parts[0] != fmt.Sprintf("%x", w.PublicKey[1:3]) { + return nil, fmt.Errorf("URL %s is not for this wallet", account.URL) + } + + return accounts.ParseDerivationPath(parts[1]) +} + +// Session represents a secured communication session with the wallet. +type Session struct { + Wallet *Wallet // A handle to the wallet that opened the session + Channel *SecureChannelSession // A secure channel for encrypted messages + verified bool // Whether the pin has been verified in this session. +} + +// pair establishes a new pairing over this channel, using the provided secret. +func (s *Session) pair(secret []byte) (smartcardPairing, error) { + err := s.Channel.Pair(secret) + if err != nil { + return smartcardPairing{}, err + } + + return smartcardPairing{ + PublicKey: s.Wallet.PublicKey, + PairingIndex: s.Channel.PairingIndex, + PairingKey: s.Channel.PairingKey, + Accounts: make(map[common.Address]accounts.DerivationPath), + }, nil +} + +// unpair deletes an existing pairing. +func (s *Session) unpair() error { + if !s.verified { + return fmt.Errorf("Unpair requires that the PIN be verified") + } + return s.Channel.Unpair() +} + +// verifyPin unlocks a wallet with the provided pin. +func (s *Session) verifyPin(pin []byte) error { + if _, err := s.Channel.transmitEncrypted(claSCWallet, insVerifyPin, 0, 0, pin); err != nil { + return err + } + s.verified = true + return nil +} + +// unblockPin unblocks a wallet with the provided puk and resets the pin to the +// new one specified. +func (s *Session) unblockPin(pukpin []byte) error { + if _, err := s.Channel.transmitEncrypted(claSCWallet, insUnblockPin, 0, 0, pukpin); err != nil { + return err + } + s.verified = true + return nil +} + +// release releases resources associated with the channel. +func (s *Session) release() error { + return s.Wallet.card.Disconnect(pcsc.LeaveCard) +} + +// paired returns true if a valid pairing exists. +func (s *Session) paired() bool { + return s.Channel.PairingKey != nil +} + +// authenticate uses an existing pairing to establish a secure channel. +func (s *Session) authenticate(pairing smartcardPairing) error { + if !bytes.Equal(s.Wallet.PublicKey, pairing.PublicKey) { + return fmt.Errorf("Cannot pair using another wallet's pairing; %x != %x", s.Wallet.PublicKey, pairing.PublicKey) + } + s.Channel.PairingKey = pairing.PairingKey + s.Channel.PairingIndex = pairing.PairingIndex + return s.Channel.Open() +} + +// walletStatus describes a smartcard wallet's status information. +type walletStatus struct { + PinRetryCount int // Number of remaining PIN retries + PukRetryCount int // Number of remaining PUK retries + Initialized bool // Whether the card has been initialized with a private key +} + +// walletStatus fetches the wallet's status from the card. +func (s *Session) walletStatus() (*walletStatus, error) { + response, err := s.Channel.transmitEncrypted(claSCWallet, insStatus, statusP1WalletStatus, 0, nil) + if err != nil { + return nil, err + } + + status := new(walletStatus) + if _, err := asn1.UnmarshalWithParams(response.Data, status, "tag:3"); err != nil { + return nil, err + } + return status, nil +} + +// derivationPath fetches the wallet's current derivation path from the card. +func (s *Session) derivationPath() (accounts.DerivationPath, error) { + response, err := s.Channel.transmitEncrypted(claSCWallet, insStatus, statusP1Path, 0, nil) + if err != nil { + return nil, err + } + buf := bytes.NewReader(response.Data) + path := make(accounts.DerivationPath, len(response.Data)/4) + return path, binary.Read(buf, binary.BigEndian, &path) +} + +// initializeData contains data needed to initialize the smartcard wallet. +type initializeData struct { + PublicKey []byte `asn1:"tag:0"` + PrivateKey []byte `asn1:"tag:1"` + ChainCode []byte `asn1:"tag:2"` +} + +// initialize initializes the card with new key data. +func (s *Session) initialize(seed []byte) error { + // Check that the wallet isn't currently initialized, + // otherwise the key would be overwritten. + status, err := s.Wallet.Status() + if err != nil { + return err + } + if status == "Online" { + return fmt.Errorf("card is already initialized, cowardly refusing to proceed") + } + + s.Wallet.lock.Lock() + defer s.Wallet.lock.Unlock() + + // HMAC the seed to produce the private key and chain code + mac := hmac.New(sha512.New, []byte("Bitcoin seed")) + mac.Write(seed) + seed = mac.Sum(nil) + + key, err := crypto.ToECDSA(seed[:32]) + if err != nil { + return err + } + + id := initializeData{} + id.PublicKey = crypto.FromECDSAPub(&key.PublicKey) + id.PrivateKey = seed[:32] + id.ChainCode = seed[32:] + data, err := asn1.Marshal(id) + if err != nil { + return err + } + + // Nasty hack to force the top-level struct tag to be context-specific + data[0] = 0xA1 + + _, err = s.Channel.transmitEncrypted(claSCWallet, insLoadKey, 0x02, 0, data) + return err +} + +// derive derives a new HD key path on the card. +func (s *Session) derive(path accounts.DerivationPath) (accounts.Account, error) { + startingPoint, path, err := derivationpath.Decode(path.String()) + if err != nil { + return accounts.Account{}, err + } + + var p1 uint8 + switch startingPoint { + case derivationpath.StartingPointMaster: + p1 = P1DeriveKeyFromMaster + case derivationpath.StartingPointParent: + p1 = P1DeriveKeyFromParent + case derivationpath.StartingPointCurrent: + p1 = P1DeriveKeyFromCurrent + default: + return accounts.Account{}, fmt.Errorf("invalid startingPoint %d", startingPoint) + } + + data := new(bytes.Buffer) + for _, segment := range path { + if err := binary.Write(data, binary.BigEndian, segment); err != nil { + return accounts.Account{}, err + } + } + + _, err = s.Channel.transmitEncrypted(claSCWallet, insDeriveKey, p1, 0, data.Bytes()) + if err != nil { + return accounts.Account{}, err + } + + response, err := s.Channel.transmitEncrypted(claSCWallet, insSign, 0, 0, DerivationSignatureHash[:]) + if err != nil { + return accounts.Account{}, err + } + + sigdata := new(signatureData) + if _, err := asn1.UnmarshalWithParams(response.Data, sigdata, "tag:0"); err != nil { + return accounts.Account{}, err + } + rbytes, sbytes := sigdata.Signature.R.Bytes(), sigdata.Signature.S.Bytes() + sig := make([]byte, 65) + copy(sig[32-len(rbytes):32], rbytes) + copy(sig[64-len(sbytes):64], sbytes) + + if err := confirmPublicKey(sig, sigdata.PublicKey); err != nil { + return accounts.Account{}, err + } + pub, err := crypto.UnmarshalPubkey(sigdata.PublicKey) + if err != nil { + return accounts.Account{}, err + } + return s.Wallet.makeAccount(crypto.PubkeyToAddress(*pub), path), nil +} + +// keyExport contains information on an exported keypair. +type keyExport struct { + PublicKey []byte `asn1:"tag:0"` + PrivateKey []byte `asn1:"tag:1,optional"` +} + +// publicKey returns the public key for the current derivation path. +func (s *Session) publicKey() ([]byte, error) { + response, err := s.Channel.transmitEncrypted(claSCWallet, insExportKey, exportP1Any, exportP2Pubkey, nil) + if err != nil { + return nil, err + } + keys := new(keyExport) + if _, err := asn1.UnmarshalWithParams(response.Data, keys, "tag:1"); err != nil { + return nil, err + } + return keys.PublicKey, nil +} + +// signatureData contains information on a signature - the signature itself and +// the corresponding public key. +type signatureData struct { + PublicKey []byte `asn1:"tag:0"` + Signature struct { + R *big.Int + S *big.Int + } +} + +// sign asks the card to sign a message, and returns a valid signature after +// recovering the v value. +func (s *Session) sign(path accounts.DerivationPath, hash []byte) ([]byte, error) { + startTime := time.Now() |