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Commit eea8d3eb authored by Alan Stokes's avatar Alan Stokes
Browse files

Tighten rules for blocking activity starts. 

This means we now block various cases where we failed to before,
including where an app launches an activity shortly after the home
button has been pressed, e.g. from within onPause() - either
immediately or after some blocking call.

Details:
- We no longer use process state at all, since a process may remain
  top for a time after the user has switched away and its
  windows have ceased to be visible.
- We no longer allow a start if callerApp.hasForegroundActivities(),
  because we are checking for windows visible to the user and an
  activity may be considered foreground even when it doesn't have such
  windows.
- Windows are only considered visible if isNowVisible() is true,
  rather than isVisible().

Bug: 128688247
Test: atest BackgroundActivityLaunchTest RootWindowContainerTests \
 WmTests:ActivityStarterTests \
 CtsActivityManagerDeviceTestCases:ActivityStarterTests
Test: Manual verification with self-restarting test app
Change-Id: I9863d8637661f15828ced435ff23812a4beef78d
parent bb8b7e57

services/core/java/com/android/server/wm/ActivityStarter.java

+5 −10
Original line number Diff line number Diff line
@@ -937,7 +937,7 @@ class ActivityStarter { 
                || callingUid == Process.NFC_UID) {

            return false;

        }

        // don't abort if the callingUid is in the foreground or is a persistent system process

        // don't abort if the callingUid has a visible window or is a persistent system process

        final int callingUidProcState = mService.getUidState(callingUid);

        final boolean callingUidHasAnyVisibleWindow =

                mService.mWindowManager.mRoot.isAnyNonToastWindowVisibleForUid(callingUid);
@@ -946,7 +946,7 @@ class ActivityStarter { 
                || callingUidProcState == ActivityManager.PROCESS_STATE_BOUND_TOP;

        final boolean isCallingUidPersistentSystemProcess = (callingUid == Process.SYSTEM_UID)

                || callingUidProcState <= ActivityManager.PROCESS_STATE_PERSISTENT_UI;

        if (isCallingUidForeground || isCallingUidPersistentSystemProcess) {

        if (callingUidHasAnyVisibleWindow || isCallingUidPersistentSystemProcess) {

            return false;

        }

        // take realCallingUid into consideration
@@ -965,8 +965,8 @@ class ActivityStarter { 
                : (realCallingUid == Process.SYSTEM_UID)

                        || realCallingUidProcState <= ActivityManager.PROCESS_STATE_PERSISTENT_UI;

        if (realCallingUid != callingUid) {

            // don't abort if the realCallingUid is in the foreground and callingUid isn't

            if (isRealCallingUidForeground) {

            // don't abort if the realCallingUid has a visible window

            if (realCallingUidHasAnyVisibleWindow) {

                return false;

            }

            // if the realCallingUid is a persistent system process, abort if the IntentSender
@@ -988,10 +988,6 @@ class ActivityStarter { 
            callerApp = mService.getProcessController(realCallingPid, realCallingUid);

        }

        if (callerApp != null) {

            // don't abort if the callerApp has any visible activity

            if (callerApp.hasForegroundActivities()) {

                return false;

            }

            // don't abort if the callerApp is instrumenting with background activity starts privs

            if (callerApp.isInstrumentingWithBackgroundActivityStartPrivileges()) {

                return false;
@@ -1061,8 +1057,7 @@ class ActivityStarter { 
        final ArraySet<Integer> boundClientUids = callerApp.getBoundClientUids();

        for (int i = boundClientUids.size() - 1; i >= 0; --i) {

            final int uid = boundClientUids.valueAt(i);

            if (mService.mWindowManager.mRoot.isAnyNonToastWindowVisibleForUid(uid)

                    || mService.getUidState(uid) == ActivityManager.PROCESS_STATE_TOP) {

            if (mService.isUidForeground(uid)) {

                return true;

            }

        }

services/core/java/com/android/server/wm/ActivityTaskManagerInternal.java

+1 −1
Original line number Diff line number Diff line
@@ -503,7 +503,7 @@ public abstract class ActivityTaskManagerInternal { 
    public abstract ActivityManager.TaskSnapshot getTaskSnapshot(int taskId,

            boolean reducedResolution);



    /** Returns true if uid has a visible window or its process is in a top state. */

    /** Returns true if uid is considered foreground for activity start purposes. */

    public abstract boolean isUidForeground(int uid);



    /**

services/core/java/com/android/server/wm/ActivityTaskManagerService.java

+2 −2
Original line number Diff line number Diff line
@@ -5872,8 +5872,8 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub { 
    }



    boolean isUidForeground(int uid) {

        return (getUidState(uid) == ActivityManager.PROCESS_STATE_TOP)

                || mWindowManager.mRoot.isAnyNonToastWindowVisibleForUid(uid);

        // A uid is considered to be foreground if it has a visible non-toast window.

        return mWindowManager.mRoot.isAnyNonToastWindowVisibleForUid(uid);

    }



    boolean isDeviceOwner(int uid) {

services/core/java/com/android/server/wm/RootWindowContainer.java

+4 −3
Original line number Diff line number Diff line
@@ -314,9 +314,10 @@ class RootWindowContainer extends WindowContainer<DisplayContent> 
     * Returns true if the callingUid has any non-toast window currently visible to the user.

     */

    boolean isAnyNonToastWindowVisibleForUid(int callingUid) {

        return forAllWindows(w -> {

            return w.getOwningUid() == callingUid && w.isVisible() && w.mAttrs.type != TYPE_TOAST;

        }, true /* traverseTopToBottom */);

        return forAllWindows(w ->

                        w.getOwningUid() == callingUid && w.mAttrs.type != TYPE_TOAST

                        && w.isVisibleNow(),

                true /* traverseTopToBottom */);

    }



    /**

services/tests/wmtests/src/com/android/server/wm/ActivityStarterTests.java

+16 −16
Original line number Diff line number Diff line
@@ -577,12 +577,27 @@ public class ActivityStarterTests extends ActivityTestsBase { 
                UNIMPORTANT_UID, false, PROCESS_STATE_TOP + 1,

                UNIMPORTANT_UID2, false, PROCESS_STATE_TOP + 1,

                false, false, false, false, false, false);

        runAndVerifyBackgroundActivityStartsSubtest(

                "disallowed_callingUidProcessStateTop_aborted", true,

                UNIMPORTANT_UID, false, PROCESS_STATE_TOP,

                UNIMPORTANT_UID2, false, PROCESS_STATE_TOP + 1,

                false, false, false, false, false, false);

        runAndVerifyBackgroundActivityStartsSubtest(

                "disallowed_realCallingUidProcessStateTop_aborted", true,

                UNIMPORTANT_UID, false, PROCESS_STATE_TOP + 1,

                UNIMPORTANT_UID2, false, PROCESS_STATE_TOP,

                false, false, false, false, false, false);

        runAndVerifyBackgroundActivityStartsSubtest(

                "disallowed_hasForegroundActivities_aborted", true,

                UNIMPORTANT_UID, false, PROCESS_STATE_TOP + 1,

                UNIMPORTANT_UID2, false, PROCESS_STATE_TOP + 1,

                true, false, false, false, false, false);

    }



    /**

     * This test ensures that supported usecases aren't aborted when background starts are

     * disallowed.

     * The scenarios each have only one condidion that makes them supported.

     * The scenarios each have only one condition that makes them supported.

     */

    @Test

    public void testBackgroundActivityStartsDisallowed_supportedStartsNotAborted() {
@@ -605,26 +620,11 @@ public class ActivityStarterTests extends ActivityTestsBase { 
                UNIMPORTANT_UID, true, PROCESS_STATE_TOP + 1,

                UNIMPORTANT_UID2, false, PROCESS_STATE_TOP + 1,

                false, false, false, false, false, false);

        runAndVerifyBackgroundActivityStartsSubtest(

                "disallowed_callingUidProcessStateTop_notAborted", false,

                UNIMPORTANT_UID, false, PROCESS_STATE_TOP,

                UNIMPORTANT_UID2, false, PROCESS_STATE_TOP + 1,

                false, false, false, false, false, false);

        runAndVerifyBackgroundActivityStartsSubtest(

                "disallowed_realCallingUidHasVisibleWindow_notAborted", false,

                UNIMPORTANT_UID, false, PROCESS_STATE_TOP + 1,

                UNIMPORTANT_UID2, true, PROCESS_STATE_TOP + 1,

                false, false, false, false, false, false);

        runAndVerifyBackgroundActivityStartsSubtest(

                "disallowed_realCallingUidProcessStateTop_notAborted", false,

                UNIMPORTANT_UID, false, PROCESS_STATE_TOP + 1,

                UNIMPORTANT_UID2, false, PROCESS_STATE_TOP,

                false, false, false, false, false, false);

        runAndVerifyBackgroundActivityStartsSubtest(

                "disallowed_hasForegroundActivities_notAborted", false,

                UNIMPORTANT_UID, false, PROCESS_STATE_TOP + 1,

                UNIMPORTANT_UID2, false, PROCESS_STATE_TOP + 1,

                true, false, false, false, false, false);

        runAndVerifyBackgroundActivityStartsSubtest(

                "disallowed_callerIsRecents_notAborted", false,

                UNIMPORTANT_UID, false, PROCESS_STATE_TOP + 1,