ensure wallet file access, fix #4507

gui/kivy/main_window.py

@@ -509,6 +509,9 @@ class ElectrumWindow(App):
             return
         wallet = self.daemon.load_wallet(path, None)
         if wallet:
+            if not wallet.storage.file_writable():
+                self.show_error(_("Wallet file not writable"))
+                return
             if wallet.has_password():
                 self.password_dialog(wallet, _('Enter PIN code'), lambda x: self.load_wallet(wallet), self.stop)
             else:

gui/kivy/uix/dialogs/wallets.py

@@ -61,5 +61,9 @@ class WalletDialog(Factory.Popup):
         d.open()
 
     def open_wallet(self, app):
-        app.load_wallet_by_name(self.ids.wallet_selector.selection[0])
+        path = self.ids.wallet_selector.selection[0]
+        if not os.access(path, os.W_OK) or not os.access(path, os.R_OK):
+            app.show_error(_("Wallet file not writable"))
+            return
+        app.load_wallet_by_name(path)
 

gui/qt/__init__.py

@@ -204,6 +204,8 @@ class ElectrumGui:
         opens the wallet and creates a new window for it'''
         try:
             wallet = self.daemon.load_wallet(path, None)
+            if wallet and not wallet.storage.file_writable():
+                raise Exception(_("Wallet file not writable"))
         except BaseException as e:
             traceback.print_exc(file=sys.stdout)
             d = QMessageBox(QMessageBox.Warning, _('Error'),

lib/base_wizard.py

@@ -91,6 +91,9 @@ class BaseWizard(object):
         self.run(action, *args)
 
     def new(self):
+        if not self.storage.file_writable():
+            self.show_error(_("Wallet file not writable"))
+            return
         name = os.path.basename(self.storage.path)
         title = _("Create") + ' ' + name
         message = '\n'.join([

lib/storage.py

@@ -165,6 +165,15 @@ class WalletStorage(PrintError):
     def file_exists(self):
         return self.path and os.path.exists(self.path)
 
+    def file_writable(self):
+        if not self.file_exists():
+            if not os.access(os.path.dirname(self.path), os.W_OK):
+                return False
+        else:
+            if not os.access(self.path, os.W_OK):
+                return False
+        return True
+
     @staticmethod
     def get_eckey_from_password(password):
         secret = pbkdf2.PBKDF2(password, '', iterations=1024, macmodule=hmac, digestmodule=hashlib.sha512).read(64)