From db74e573d13a69601219f9e5b8b752bebc4669f6 Mon Sep 17 00:00:00 2001
From: Philipp Crocoll <philipp@crocoll.net>
Date: Sat, 2 Dec 2017 16:41:57 +0100
Subject: [PATCH] catch exception when decrypting key fails, fixes #50

---
 src/keepass2android/PasswordActivity.cs | 33 ++++++++++++++++++-------
 src/keepass2android/QuickUnlock.cs      | 15 +++++++----
 2 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/src/keepass2android/PasswordActivity.cs b/src/keepass2android/PasswordActivity.cs
index b48a03d2..04a38b97 100644
--- a/src/keepass2android/PasswordActivity.cs
+++ b/src/keepass2android/PasswordActivity.cs
@@ -1054,10 +1054,19 @@ namespace keepass2android
 			var btn = FindViewById<ImageButton>(Resource.Id.fingerprintbtn);
 
 			btn.SetImageResource(Resource.Drawable.ic_fingerprint_success);
-			
-			var masterPassword = _fingerprintDec.DecryptStored(Database.GetFingerprintPrefKey(_ioConnection));
-			_password = FindViewById<EditText>(Resource.Id.password_edit).Text = masterPassword;
 
+			try
+			{
+				var masterPassword = _fingerprintDec.DecryptStored(Database.GetFingerprintPrefKey(_ioConnection));
+				_password = FindViewById<EditText>(Resource.Id.password_edit).Text = masterPassword;
+
+			}
+			catch (Java.Security.GeneralSecurityException ex)
+			{
+				HandleFingerprintKeyInvalidated();
+				return;
+			}
+			
 			btn.PostDelayed(() =>
 			{
 				//re-init fingerprint unlock in case something goes wrong with opening the database 
@@ -1961,12 +1970,7 @@ namespace keepass2android
 				}
 				else
 				{
-					//key invalidated permanently
-					btn.SetImageResource(Resource.Drawable.ic_fingerprint_error);
-					btn.Tag = GetString(Resource.String.fingerprint_unlock_failed);
-					_fingerprintDec = null;
-
-					ClearFingerprintUnlockData();
+					HandleFingerprintKeyInvalidated();
 					return false;
 				}
 			}
@@ -1982,6 +1986,17 @@ namespace keepass2android
 				
 		}
 
+		private void HandleFingerprintKeyInvalidated()
+		{
+			var btn = FindViewById<ImageButton>(Resource.Id.fingerprintbtn);
+//key invalidated permanently
+			btn.SetImageResource(Resource.Drawable.ic_fingerprint_error);
+			btn.Tag = GetString(Resource.String.fingerprint_unlock_failed);
+			_fingerprintDec = null;
+
+			ClearFingerprintUnlockData();
+		}
+
 		private void InitializeOptionCheckboxes() {
 			CheckBox cbQuickUnlock = (CheckBox)FindViewById(Resource.Id.enable_quickunlock);
 			cbQuickUnlock.Checked = _prefs.GetBoolean(GetString(Resource.String.QuickUnlockDefaultEnabled_key), true);
diff --git a/src/keepass2android/QuickUnlock.cs b/src/keepass2android/QuickUnlock.cs
index 8ba3d556..b2ce30ea 100644
--- a/src/keepass2android/QuickUnlock.cs
+++ b/src/keepass2android/QuickUnlock.cs
@@ -285,11 +285,7 @@ namespace keepass2android
 				else
 				{
 					Kp2aLog.Log("failed to initialize fingerprint.");
-					//key invalidated permanently
-					btn.SetImageResource(Resource.Drawable.ic_fingerprint_error);
-					btn.Tag = GetString(Resource.String.fingerprint_unlock_failed);
-					_fingerprintIdentifier = null;
-
+					HandleFingerprintKeyInvalidated();
 				}
 			}
 			catch (Exception e)
@@ -304,6 +300,15 @@ namespace keepass2android
 
 		}
 
+		private void HandleFingerprintKeyInvalidated()
+		{
+			var btn = FindViewById<ImageButton>(Resource.Id.fingerprintbtn);
+//key invalidated permanently
+			btn.SetImageResource(Resource.Drawable.ic_fingerprint_error);
+			btn.Tag = GetString(Resource.String.fingerprint_unlock_failed);
+			_fingerprintIdentifier = null;
+		}
+
 		private void ClearFingerprintUnlockData()
 		{
 			ISharedPreferencesEditor edit = PreferenceManager.GetDefaultSharedPreferences(this).Edit();