Fix 5437700: Underlying backup method was exposed

At one point we added a timeout to the black box that covers the
underlying backup unlock method so if Face Unlock doesn't start or
crashes, the user will see the backup method rather than being stuck
looking at a black box.  However, when powering the phone on and off
quickly, the message to time out the black box could be received at
the wrong time, causing it to expose the underlying backup method
when it shouldn't.

This solution clears the existing SHOW/HIDE messages from the
handler's message queue before sending a new SHOW/HIDE message.  In
particular, it clears out a delayed HIDE message when a SHOW is sent
so the SHOW can't be undone by a pending delayed HIDE message.

Also, logging errors for a couple of exceptions instead of rethrowing
so we can gracefully go to the backup in these cases.

Patch set 2 fixes problem where rare exceptions could prevent ever
binding to the service again because mBoundToFaceLockService was still
true.

Change-Id: Ieb7b6723161070f509277f67dc9ef100cf7c1aa6

1 files changed, 54 insertions, 19 deletions

diff --git a/policy/src/com/android/internal/policy/impl/LockPatternKeyguardView.java b/policy/src/com/android/internal/policy/impl/LockPatternKeyguardView.java
index a010ba1..0c44e45 100644
--- a/policy/src/com/android/internal/policy/impl/LockPatternKeyguardView.java
+++ b/policy/src/com/android/internal/policy/impl/LockPatternKeyguardView.java
@@ -117,9 +117,14 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
     private final int MSG_SHOW_FACELOCK_AREA_VIEW = 0;
     private final int MSG_HIDE_FACELOCK_AREA_VIEW = 1;
 
-    // Long enough to stay black while dialer comes up
-    // Short enough to not be black if the user goes back immediately
-    private final int FACELOCK_VIEW_AREA_EMERGENCY_HIDE_TIMEOUT = 1000;
+    // Long enough to stay visible while dialer comes up
+    // Short enough to not be visible if the user goes back immediately
+    private final int FACELOCK_VIEW_AREA_EMERGENCY_DIALER_TIMEOUT = 1000;
+
+    // Long enough to stay visible while the service starts
+    // Short enough to not have to wait long for backup if service fails to start or crashes
+    // The service can take a couple of seconds to start on the first try after boot
+    private final int FACELOCK_VIEW_AREA_SERVICE_TIMEOUT = 3000;
 
     /**
      * The current {@link KeyguardScreen} will use this to communicate back to us.
@@ -328,9 +333,8 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
                 // FaceLock must be stopped if it is running when emergency call is pressed
                 stopAndUnbindFromFaceLock();
 
-                // Delay hiding FaceLock area so unlock doesn't display while dialer is coming up
-                mHandler.sendEmptyMessageDelayed(MSG_HIDE_FACELOCK_AREA_VIEW,
-                        FACELOCK_VIEW_AREA_EMERGENCY_HIDE_TIMEOUT);
+                // Continue showing FaceLock area until dialer comes up
+                showFaceLockAreaWithTimeout(FACELOCK_VIEW_AREA_EMERGENCY_DIALER_TIMEOUT);
 
                 pokeWakelock(EMERGENCY_CALL_TIMEOUT);
                 if (TelephonyManager.getDefault().getCallState()
@@ -529,11 +533,11 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
         if (mUpdateMonitor.getPhoneState() == TelephonyManager.CALL_STATE_IDLE
                 && transportInvisible) {
             bindToFaceLock();
-            //Eliminate the black background so that the lockpattern will be visible
-            //If FaceUnlock is cancelled
-            mHandler.sendEmptyMessageDelayed(MSG_HIDE_FACELOCK_AREA_VIEW, 4000);
+            // Show FaceLock area, but only for a little bit so lockpattern will become visible if
+            // FaceLock fails to start or crashes
+            showFaceLockAreaWithTimeout(FACELOCK_VIEW_AREA_SERVICE_TIMEOUT);
         } else {
-            mHandler.sendEmptyMessage(MSG_HIDE_FACELOCK_AREA_VIEW);
+            hideFaceLockArea();
         }
     }
 
@@ -563,7 +567,7 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
         }
         if(!hasWindowFocus) {
             stopAndUnbindFromFaceLock();
-            mHandler.sendEmptyMessage(MSG_HIDE_FACELOCK_AREA_VIEW);
+            hideFaceLockArea();
         } else if (runFaceLock) {
             //Don't activate facelock while the user is calling 911!
             if(mEmergencyCall) mEmergencyCall = false;
@@ -583,9 +587,9 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
 
         if (mLockPatternUtils.usingBiometricWeak() &&
                 mLockPatternUtils.isBiometricWeakInstalled()) {
-            mHandler.sendEmptyMessage(MSG_SHOW_FACELOCK_AREA_VIEW);
+            showFaceLockArea();
         } else {
-            mHandler.sendEmptyMessage(MSG_HIDE_FACELOCK_AREA_VIEW);
+            hideFaceLockArea();
         }
     }
 
@@ -652,7 +656,7 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
         if (DEBUG) Log.d(TAG, "phone state: " + phoneState);
         if(phoneState == TelephonyManager.CALL_STATE_RINGING) {
             stopAndUnbindFromFaceLock();
-            mHandler.sendEmptyMessage(MSG_HIDE_FACELOCK_AREA_VIEW);
+            hideFaceLockArea();
         }
     }
 
@@ -1085,6 +1089,32 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
         return true;
     }
 
+    // Removes show and hide messages from the message queue
+    private void removeFaceLockAreaDisplayMessages() {
+        mHandler.removeMessages(MSG_SHOW_FACELOCK_AREA_VIEW);
+        mHandler.removeMessages(MSG_HIDE_FACELOCK_AREA_VIEW);
+    }
+
+    // Shows the FaceLock area immediately
+    private void showFaceLockArea() {
+        // Remove messages to prevent a delayed hide message from undo-ing the show
+        removeFaceLockAreaDisplayMessages();
+        mHandler.sendEmptyMessage(MSG_SHOW_FACELOCK_AREA_VIEW);
+    }
+
+    // Hides the FaceLock area immediately
+    private void hideFaceLockArea() {
+        // Remove messages to prevent a delayed show message from undo-ing the hide
+        removeFaceLockAreaDisplayMessages();
+        mHandler.sendEmptyMessage(MSG_HIDE_FACELOCK_AREA_VIEW);
+    }
+
+    // Shows the FaceLock area for a period of time
+    private void showFaceLockAreaWithTimeout(long timeoutMillis) {
+        showFaceLockArea();
+        mHandler.sendEmptyMessageDelayed(MSG_HIDE_FACELOCK_AREA_VIEW, timeoutMillis);
+    }
+
     // Binds to FaceLock service, but does not tell it to start
     public void bindToFaceLock() {
         if (mLockPatternUtils.usingBiometricWeak() &&
@@ -1130,7 +1160,10 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
             try {
                 mFaceLockService.registerCallback(mFaceLockCallback);
             } catch (RemoteException e) {
-                throw new RuntimeException("Remote exception");
+                Log.e(TAG, "Caught exception connecting to FaceLock: " + e.toString());
+                mFaceLockService = null;
+                mBoundToFaceLockService = false;
+                return;
             }
 
             if (mFaceLockAreaView != null) {
@@ -1147,6 +1180,7 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
                 mFaceLockService = null;
                 mFaceLockServiceRunning = false;
             }
+            mBoundToFaceLockService = false;
             Log.w(TAG, "Unexpected disconnect from FaceLock service");
         }
     };
@@ -1162,7 +1196,8 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
                     try {
                         mFaceLockService.startUi(windowToken, x, y, h, w);
                     } catch (RemoteException e) {
-                        throw new RuntimeException("Remote exception");
+                        Log.e(TAG, "Caught exception starting FaceLock: " + e.toString());
+                        return;
                     }
                     mFaceLockServiceRunning = true;
                 } else {
@@ -1186,7 +1221,7 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
                         if (DEBUG) Log.d(TAG, "Stopping FaceLock");
                         mFaceLockService.stopUi();
                     } catch (RemoteException e) {
-                        throw new RuntimeException("Remote exception");
+                        Log.e(TAG, "Caught exception stopping FaceLock: " + e.toString());
                     }
                     mFaceLockServiceRunning = false;
                 }
@@ -1201,7 +1236,7 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
         @Override
         public void unlock() {
             if (DEBUG) Log.d(TAG, "FaceLock unlock()");
-            mHandler.sendEmptyMessage(MSG_SHOW_FACELOCK_AREA_VIEW); // Keep fallback covered
+            showFaceLockArea(); // Keep fallback covered
             stopFaceLock();
 
             mKeyguardScreenCallback.keyguardDone(true);
@@ -1213,7 +1248,7 @@ public class LockPatternKeyguardView extends KeyguardViewBase implements Handler
         @Override
         public void cancel() {
             if (DEBUG) Log.d(TAG, "FaceLock cancel()");
-            mHandler.sendEmptyMessage(MSG_HIDE_FACELOCK_AREA_VIEW); // Expose fallback
+            hideFaceLockArea(); // Expose fallback
             stopFaceLock();
         }