From bb54d71a33a41a3621a952dee7455bfc04b48db1 Mon Sep 17 00:00:00 2001
From: Xiaozhen Lin <xiaozhenl@google.com>
Date: Thu, 27 Apr 2023 23:07:02 +0000
Subject: [PATCH] Password clearing in Settings App

Pixel Imprint will call onDestroy() whenever its menu is invisible.
(https://cs.android.com/android/platform/superproject/+/master:packages/apps/Settings/src/com/android/settings/biometrics/fingerprint/FingerprintSettings.java;l=639?q=packages%2Fapps%2FSettings%2Fsrc%2Fcom%2Fandroid%2Fsettings%2Fbiometrics%2Ffingerprint%2FFingerprintSettings.java&ss=android)
However, Screen lock should have the same behavior as Pixel Imprint but
it doesn't.
onDestroy() for Screen lock should be called whenever we exit the menu
or the menu becomes invisible. Otherwise, the password may be leaked to
RAM unexpectedly in some situations.

Bug: 233373529
Bug: 278488549
Bug: 278530059
Test: manual
Change-Id: Ib11af7073aa1c49096a66c9f5a462e7caf18df5e
---
 .../settings/password/ChooseLockGeneric.java        | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/com/android/settings/password/ChooseLockGeneric.java b/src/com/android/settings/password/ChooseLockGeneric.java
index e35b0d82181..0bf13b15c0c 100644
--- a/src/com/android/settings/password/ChooseLockGeneric.java
+++ b/src/com/android/settings/password/ChooseLockGeneric.java
@@ -853,6 +853,19 @@ public class ChooseLockGeneric extends SettingsActivity {
             return intent;
         }
 
+        @Override
+        public void onStop() {
+            super.onStop();
+            // hasCredential checks to see if user chooses a password for screen lock. If the
+            // screen lock is None or Swipe, we do not want to call getActivity().finish().
+            // Otherwise, bugs would be caused. (e.g. b/278488549, b/278530059)
+            final boolean hasCredential = mLockPatternUtils.isSecure(mUserId);
+            if (!getActivity().isChangingConfigurations()
+                    && !mWaitingForConfirmation && hasCredential) {
+                getActivity().finish();
+            }
+        }
+
         @Override
         public void onDestroy() {
             super.onDestroy();