What the developer wrote
Authored by f321x
android: biometry: catch java import errors
Catch JavaError when trying to load the java classes of the biometry
module on startup. This can raise if the device is on an old API version
and the loaded java class depends on apis unknown to the os.
Fixes #10470
```
02-17 10:07:25.714 5254 5270 I python : 0.47 | E | __main__ | daemon.run_gui errored
02-17 10:07:25.714 5254 5270 I python : Traceback (most recent call last):
02-17 10:07:25.714 5254 5270 I python : File "app/main.py", line 514, in handle_cmd
02-17 10:07:25.714 5254 5270 I python : File "app/electrum/daemon.py", line 653, in run_gui
02-17 10:07:25.714 5254 5270 I python : File "app/electrum/gui/qml/__init__.py", line 38, in <module>
02-17 10:07:25.714 5254 5270 I python : File "app/electrum/gui/qml/qeapp.py", line 49, in <module>
02-17 10:07:25.714 5254 5270 I python : File "app/electrum/gui/qml/qebiometrics.py", line 33, in <module>
02-17 10:07:25.714 5254 5270 I python : File "jnius/reflect.py", line 243, in autoclass
02-17 10:07:25.714 5254 5270 I python : File "jnius/jnius_export_class.pxi", line 877, in jnius.jnius.JavaMethod.__call__
02-17 10:07:25.714 5254 5270 I python : File "jnius/jnius_export_class.pxi", line 964, in jnius.jnius.JavaMethod.call_method
02-17 10:07:25.714 5254 5270 I python : File "jnius/jnius_utils.pxi", line 79, in jnius.jnius.check_exception
02-17 10:07:25.714 5254 5270 I python : jnius.jnius.JavaException: JVM exception occurred: Failed resolution of: Landroid/hardware/biometrics/BiometricPrompt$AuthenticationResult; java.lang.NoClassDefFoundError
```
What changed, and why it matters
This commit fixes a crash in the Electrum Android app when it starts on older Android devices. The app was trying to load modern fingerprint/face-unlock Java classes that don't exist on old Android versions, causing an uncaught exception and preventing the app from opening. The fix catches that loading error and gracefully disables biometric features instead of crashing.
No immediate security action required; this is a robustness fix. Users on affected old Android devices should update to a release containing this commit. Consider adding a minimum Android API level check or feature flag to avoid similar import-time failures.
Security signals we found
Denial-of-service (app crash on startup) on older Android devices due to uncaught Java class-loading exception
Graceful degradation pattern: catch import-time platform-availability failure and disable feature
Evidence from the diff
In electrum/gui/qml/qebiometrics.py, autoclass() calls for Android biometric Java classes are now wrapped in a try/except catching jnius.JavaException. If loading fails (e.g., NoClassDefFoundError for android/hardware/biometrics/BiometricPrompt$AuthenticationResult on old API levels), the biometric helper variables remain None and isAvailable returns False. This prevents an unhandled exception during QML GUI module import at daemon startup.
Changed components
electrum/gui/qml/qebiometrics.pyAndroid QML GUI biometric authentication initializationInspect captured patch +10 / −7
diff --git a/electrum/gui/qml/qebiometrics.py b/electrum/gui/qml/qebiometrics.py
index 3d806a6..b2d896b 100644
--- a/electrum/gui/qml/qebiometrics.py
+++ b/electrum/gui/qml/qebiometrics.py
@@ -26,13 +26,16 @@ jIntent = None
jString = None
if 'ANDROID_DATA' in os.environ:
- from jnius import autoclass
+ from jnius import autoclass, JavaException
from android import activity
- jPythonActivity = autoclass('org.kivy.android.PythonActivity').mActivity
- jBiometricHelper = autoclass('org.electrum.biometry.BiometricHelper')
- jBiometricActivity = autoclass('org.electrum.biometry.BiometricActivity')
- jIntent = autoclass('android.content.Intent')
- jString = autoclass('java.lang.String')
+ try:
+ jPythonActivity = autoclass('org.kivy.android.PythonActivity').mActivity
+ jIntent = autoclass('android.content.Intent')
+ jString = autoclass('java.lang.String')
+ jBiometricActivity = autoclass('org.electrum.biometry.BiometricActivity')
+ jBiometricHelper = autoclass('org.electrum.biometry.BiometricHelper')
+ except JavaException as e:
+ _logger.error(f"Could not load Biometric java classes (maybe due to old api version): {e}")
class BiometricAction(str, Enum):
@@ -56,7 +59,7 @@ class QEBiometrics(AuthMixin, QObject):
@pyqtProperty(bool, constant=True)
def isAvailable(self) -> bool:
- if 'ANDROID_DATA' not in os.environ:
+ if 'ANDROID_DATA' not in os.environ or jBiometricHelper is None:
return False
try:
return jBiometricHelper.isAvailable(jPythonActivity)
Why this scored 23/100
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