Make sure that external callers cannot pass in the confirm bypass extra

Security fix for vulnerability where an app could launch into the screen lock
change dialog without first confirming the existing password/pattern.

Also, make sure that the fragments are launched with the correct corresponding
activity.

Bug: 9858403
Change-Id: I0f2c00a44abeb624c6fba0497bf6036a6f1a4564

src/com/android/settings/ChooseLockPattern.java

@@ -308,6 +308,9 @@ public class ChooseLockPattern extends PreferenceActivity {
         public void onCreate(Bundle savedInstanceState) {
             super.onCreate(savedInstanceState);
             mChooseLockSettingsHelper = new ChooseLockSettingsHelper(getActivity());
+            if (!(getActivity() instanceof ChooseLockPattern)) {
+                throw new SecurityException("Fragment contained in wrong activity");
+            }
         }
 
         @Override
@@ -338,7 +341,7 @@ public class ChooseLockPattern extends PreferenceActivity {
             topLayout.setDefaultTouchRecepient(mLockPatternView);
 
             final boolean confirmCredentials = getActivity().getIntent()
-                    .getBooleanExtra("confirm_credentials", false);
+                    .getBooleanExtra("confirm_credentials", true);
 
             if (savedInstanceState == null) {
                 if (confirmCredentials) {