accounts: eip-712 signing for ledger (#22378)

* accounts: eip-712 signing for ledger

* address review comments

accounts/usbwallet/wallet.go

@@ -67,6 +67,8 @@ type driver interface {
 	// SignTx sends the transaction to the USB device and waits for the user to confirm
 	// or deny the transaction.
 	SignTx(path accounts.DerivationPath, tx *types.Transaction, chainID *big.Int) (common.Address, *types.Transaction, error)
+
+	SignTypedMessage(path accounts.DerivationPath, messageHash []byte, domainHash []byte) ([]byte, error)
 }
 
 // wallet represents the common functionality shared by all USB hardware
@@ -524,7 +526,46 @@ func (w *wallet) signHash(account accounts.Account, hash []byte) ([]byte, error)
 
 // SignData signs keccak256(data). The mimetype parameter describes the type of data being signed
 func (w *wallet) SignData(account accounts.Account, mimeType string, data []byte) ([]byte, error) {
-	return w.signHash(account, crypto.Keccak256(data))
+
+	// Unless we are doing 712 signing, simply dispatch to signHash
+	if !(mimeType == accounts.MimetypeTypedData && len(data) == 66 && data[0] == 0x19 && data[1] == 0x01) {
+		return w.signHash(account, crypto.Keccak256(data))
+	}
+
+	// dispatch to 712 signing if the mimetype is TypedData and the format matches
+	w.stateLock.RLock() // Comms have own mutex, this is for the state fields
+	defer w.stateLock.RUnlock()
+
+	// If the wallet is closed, abort
+	if w.device == nil {
+		return nil, accounts.ErrWalletClosed
+	}
+	// Make sure the requested account is contained within
+	path, ok := w.paths[account.Address]
+	if !ok {
+		return nil, accounts.ErrUnknownAccount
+	}
+	// All infos gathered and metadata checks out, request signing
+	<-w.commsLock
+	defer func() { w.commsLock <- struct{}{} }()
+
+	// Ensure the device isn't screwed with while user confirmation is pending
+	// TODO(karalabe): remove if hotplug lands on Windows
+	w.hub.commsLock.Lock()
+	w.hub.commsPend++
+	w.hub.commsLock.Unlock()
+
+	defer func() {
+		w.hub.commsLock.Lock()
+		w.hub.commsPend--
+		w.hub.commsLock.Unlock()
+	}()
+	// Sign the transaction
+	signature, err := w.driver.SignTypedMessage(path, data[2:34], data[34:66])
+	if err != nil {
+		return nil, err
+	}
+	return signature, nil
 }
 
 // SignDataWithPassphrase implements accounts.Wallet, attempting to sign the given