hww: distinguish devices based on "soft device id" (not just labels)

fixes #5759

electrum/base_wizard.py

@@ -438,6 +438,7 @@ class BaseWizard(Logger):
             if not client: raise Exception("failed to find client for device id")
             root_fingerprint = client.request_root_fingerprint_from_device()
             label = client.label()  # use this as device_info.label might be outdated!
+            soft_device_id = client.get_soft_device_id()  # use this as device_info.device_id might be outdated!
         except ScriptTypeNotSupported:
             raise  # this is handled in derivation_dialog
         except BaseException as e:
@@ -451,6 +452,7 @@ class BaseWizard(Logger):
             'root_fingerprint': root_fingerprint,
             'xpub': xpub,
             'label': label,
+            'soft_device_id': soft_device_id,
         }
         k = hardware_keystore(d)
         self.on_keystore(k)
@@ -612,7 +614,7 @@ class BaseWizard(Logger):
         if os.path.exists(path):
             raise Exception('file already exists at path')
         if not self.pw_args:
-            return
+            return  # FIXME
         pw_args = self.pw_args
         self.pw_args = None  # clean-up so that it can get GC-ed
         storage = WalletStorage(path)

electrum/keystore.py

@@ -724,6 +724,7 @@ class Hardware_KeyStore(Xpub, KeyStore):
         # device reconnects
         self.xpub = d.get('xpub')
         self.label = d.get('label')
+        self.soft_device_id = d.get('soft_device_id')  # type: Optional[str]
         self.handler = None  # type: Optional[HardwareHandlerBase]
         run_hook('init_keystore', self)
 
@@ -747,6 +748,7 @@ class Hardware_KeyStore(Xpub, KeyStore):
             'derivation': self.get_derivation_prefix(),
             'root_fingerprint': self.get_root_fingerprint(),
             'label':self.label,
+            'soft_device_id': self.soft_device_id,
         }
 
     def unpaired(self):
@@ -788,6 +790,9 @@ class Hardware_KeyStore(Xpub, KeyStore):
         if self.label != client.label():
             self.label = client.label()
             self.is_requesting_to_be_rewritten_to_wallet_file = True
+        if self.soft_device_id != client.get_soft_device_id():
+            self.soft_device_id = client.get_soft_device_id()
+            self.is_requesting_to_be_rewritten_to_wallet_file = True
 
 
 KeyStoreWithMPK = Union[KeyStore, MasterPublicKeyMixin]  # intersection really...

electrum/plugin.py

@@ -306,6 +306,7 @@ class DeviceInfo(NamedTuple):
     initialized: Optional[bool] = None
     exception: Optional[Exception] = None
     plugin_name: Optional[str] = None  # manufacturer, e.g. "trezor"
+    soft_device_id: Optional[str] = None  # if available, used to distinguish same-type hw devices
 
 
 class HardwarePluginToScan(NamedTuple):
@@ -548,7 +549,8 @@ class DeviceMgr(ThreadJob):
             infos.append(DeviceInfo(device=device,
                                     label=client.label(),
                                     initialized=client.is_initialized(),
-                                    plugin_name=plugin.name))
+                                    plugin_name=plugin.name,
+                                    soft_device_id=client.get_soft_device_id()))
 
         return infos
 
@@ -575,6 +577,11 @@ class DeviceMgr(ThreadJob):
             devices = None
         if len(infos) == 1:
             return infos[0]
+        # select device by id
+        if keystore.soft_device_id:
+            for info in infos:
+                if info.soft_device_id == keystore.soft_device_id:
+                    return info
         # select device by label automatically;
         # but only if not a placeholder label and only if there is no collision
         device_labels = [info.label for info in infos]
@@ -583,7 +590,7 @@ class DeviceMgr(ThreadJob):
             for info in infos:
                 if info.label == keystore.label:
                     return info
-        # ask user to select device
+        # ask user to select device manually
         msg = _("Please select which {} device to use:").format(plugin.device)
         descriptions = ["{label} ({init}, {transport})"
                         .format(label=info.label or _("An unnamed {}").format(info.plugin_name),
@@ -594,8 +601,9 @@ class DeviceMgr(ThreadJob):
         if c is None:
             raise UserCancelled()
         info = infos[c]
-        # save new label
+        # save new label / soft_device_id
         keystore.set_label(info.label)
+        keystore.soft_device_id = info.soft_device_id
         wallet = handler.get_wallet()
         if wallet is not None:
             wallet.save_keystore()

electrum/plugins/hw_wallet/plugin.py

@@ -167,7 +167,7 @@ class HW_PluginBase(BasePlugin):
 class HardwareClientBase:
 
     plugin: 'HW_PluginBase'
-    handler: Optional['HardwareHandlerBase']
+    handler = None  # type: Optional['HardwareHandlerBase']
 
     def is_pairable(self) -> bool:
         raise NotImplementedError()
@@ -191,6 +191,16 @@ class HardwareClientBase:
         """
         raise NotImplementedError()
 
+    def get_soft_device_id(self) -> Optional[str]:
+        """An id-like string that is used to distinguish devices programmatically.
+        This is a long term id for the device, that does not change between reconnects.
+        This method should not prompt the user, i.e. no user interaction, as it is used
+        during USB device enumeration (called for each unpaired device).
+        Stored in the wallet file.
+        """
+        # This functionality is optional. If not implemented just return None:
+        return None
+
     def has_usable_connection_with_device(self) -> bool:
         raise NotImplementedError()
 

electrum/plugins/keepkey/clientbase.py

@@ -119,6 +119,9 @@ class KeepKeyClientBase(HardwareClientBase, GuiMixin, Logger):
     def label(self):
         return self.features.label
 
+    def get_soft_device_id(self):
+        return self.features.device_id
+
     def is_initialized(self):
         return self.features.initialized
 

electrum/plugins/ledger/ledger.py

@@ -66,6 +66,7 @@ class Ledger_Client(HardwareClientBase):
         self.dongleObject = btchip(hidDevice)
         self.preflightDone = False
         self._is_hw1 = is_hw1
+        self._soft_device_id = None
 
     def is_pairable(self):
         return True
@@ -82,6 +83,14 @@ class Ledger_Client(HardwareClientBase):
     def label(self):
         return ""
 
+    def get_soft_device_id(self):
+        if self._soft_device_id is None:
+            # modern ledger can provide xpub without user interaction
+            # (hw1 would prompt for PIN)
+            if not self.is_hw1():
+                self._soft_device_id = self.request_root_fingerprint_from_device()
+        return self._soft_device_id
+
     def is_hw1(self) -> bool:
         return self._is_hw1
 
@@ -176,7 +185,8 @@ class Ledger_Client(HardwareClientBase):
                     # Acquire the new client on the next run
                 else:
                     raise e
-            if self.has_detached_pin_support(self.dongleObject) and not self.is_pin_validated(self.dongleObject) and (self.handler is not None):
+            if self.has_detached_pin_support(self.dongleObject) and not self.is_pin_validated(self.dongleObject):
+                assert self.handler, "no handler for client"
                 remaining_attempts = self.dongleObject.getVerifyPinRemainingAttempts()
                 if remaining_attempts != 1:
                     msg = "Enter your Ledger PIN - remaining attempts : " + str(remaining_attempts)

electrum/plugins/safe_t/clientbase.py

@@ -121,6 +121,9 @@ class SafeTClientBase(HardwareClientBase, GuiMixin, Logger):
     def label(self):
         return self.features.label
 
+    def get_soft_device_id(self):
+        return self.features.device_id
+
     def is_initialized(self):
         return self.features.initialized
 

electrum/plugins/trezor/clientbase.py

@@ -98,6 +98,9 @@ class TrezorClientBase(HardwareClientBase, Logger):
     def label(self):
         return self.features.label
 
+    def get_soft_device_id(self):
+        return self.features.device_id
+
     def is_initialized(self):
         return self.features.initialized