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Commit 2903f3d5 authored by Hani Kazmi's avatar Hani Kazmi Committed by Cherrypicker Worker
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Update ASM clear task to only conisder present DisplayArea 

If a task is not associated with a DisplayArea, that could throw a NPE.
We now exit early if that is the case.

Extrated the ASM logic to a separate method to make it easier to follow,
and minor updates to logging to match activity starts.

Bug: 270118065
Test: atest CtsAppTestCases
Change-Id: Iabd7c7c3ca503c354014e4fe73d449570cf4ceb5
(cherry picked from commit 6e9e524b)
Merged-In: Iabd7c7c3ca503c354014e4fe73d449570cf4ceb5
parent edb6afca

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

+3 −12
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ import static com.android.server.wm.ActivityTaskManagerService.ANIMATE; 
import static com.android.server.wm.ActivityTaskSupervisor.DEFER_RESUME;

import static com.android.server.wm.ActivityTaskSupervisor.ON_TOP;

import static com.android.server.wm.ActivityTaskSupervisor.PRESERVE_WINDOWS;

import static com.android.server.wm.ActivityTaskSupervisor.getApplicationLabel;

import static com.android.server.wm.BackgroundActivityStartController.BAL_ALLOW_ALLOWLISTED_COMPONENT;

import static com.android.server.wm.BackgroundActivityStartController.BAL_ALLOW_ALLOWLISTED_UID;

import static com.android.server.wm.BackgroundActivityStartController.BAL_ALLOW_DEFAULT;
@@ -2017,7 +2018,8 @@ class ActivityStarter { 
        if (ActivitySecurityModelFeatureFlags.shouldShowToast(mCallingUid)) {

            String toastText = ActivitySecurityModelFeatureFlags.DOC_LINK

                    + (blockActivityStartAndFeatureEnabled ? " blocked " : " would block ")

                    + getApplicationLabel(launchedFromPackageName);

                    + getApplicationLabel(mService.mContext.getPackageManager(),

                        launchedFromPackageName);

            UiThread.getHandler().post(() -> Toast.makeText(mService.mContext,

                    toastText, Toast.LENGTH_LONG).show());
@@ -2039,17 +2041,6 @@ class ActivityStarter { 
        return true;

    }



    private CharSequence getApplicationLabel(String packageName) {

        try {

            PackageManager packageManager = mService.mContext.getPackageManager();

            ApplicationInfo launchedFromPackageInfo = packageManager.getApplicationInfo(

                    packageName, PackageManager.ApplicationInfoFlags.of(0));

            return packageManager.getApplicationLabel(launchedFromPackageInfo);

        } catch (PackageManager.NameNotFoundException e) {

            return packageName;

        }

    }



    /** Only called when an activity launch may be blocked, which should happen very rarely */

    private void logDebugInfoForActivitySecurity(String action, ActivityRecord r, Task targetTask,

            ActivityRecord targetTopActivity, boolean blockActivityStartAndFeatureEnabled,

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

+106 −69
Original line number Diff line number Diff line
@@ -1635,20 +1635,50 @@ public class ActivityTaskSupervisor implements RecentTasks.Callbacks { 
            // Prevent recursion.

            return;

        }

        boolean shouldBlockActivitySwitchIfFeatureEnabled = false;

        boolean wouldBlockActivitySwitchIgnoringFlags = false;

        task.mTransitionController.requestCloseTransitionIfNeeded(task);

        task.mInRemoveTask = true;

        try {

            task.removeActivities(reason, false /* excludingTaskOverlay */);

            cleanUpRemovedTaskLocked(task, killProcess, removeFromRecents);

            mService.getLockTaskController().clearLockedTask(task);

            mService.getTaskChangeNotificationController().notifyTaskStackChanged();

            if (task.isPersistable) {

                mService.notifyTaskPersisterLocked(null, true);

            }

            checkActivitySecurityForTaskClear(callingUid, task, callerActivityClassName);

        } finally {

            task.mInRemoveTask = false;

        }

    }



    // TODO(b/263368846) Move to live with the rest of the ASM logic.

    /**

     * Returns home if the passed in callingUid is not top of the stack, rather than returning to

     * previous task.

     */

    private void checkActivitySecurityForTaskClear(int callingUid, Task task,

            String callerActivityClassName) {

        // We may have already checked that the callingUid has additional clearTask privileges, and

        // cleared the calling identify. If so, we infer we do not need further restrictions here.

        // TODO(b/263368846) Move to live with the rest of the ASM logic.

        if (callingUid != SYSTEM_UID) {

            Pair<Boolean, Boolean> pair = doesTopActivityMatchingUidExistForAsm(task,

                    callingUid,

                    null);

            shouldBlockActivitySwitchIfFeatureEnabled = !pair.first;

            wouldBlockActivitySwitchIgnoringFlags = !pair.second;

            if (wouldBlockActivitySwitchIgnoringFlags) {

                ActivityRecord topActivity =  task.getActivity(ar ->

                        !ar.finishing && !ar.isAlwaysOnTop());

        if (callingUid == SYSTEM_UID) {

            return;

        }



        TaskDisplayArea displayArea = task.getTaskDisplayArea();

        if (displayArea == null) {

            // If there is no associated display area, we can not return home.

            return;

        }



        Pair<Boolean, Boolean> pair = doesTopActivityMatchingUidExistForAsm(task, callingUid, null);

        boolean shouldBlockActivitySwitchIfFeatureEnabled = !pair.first;

        boolean wouldBlockActivitySwitchIgnoringFlags = !pair.second;



        if (!wouldBlockActivitySwitchIgnoringFlags) {

            return;

        }



        ActivityRecord topActivity = task.getActivity(ar -> !ar.finishing && !ar.isAlwaysOnTop());

        FrameworkStatsLog.write(FrameworkStatsLog.ACTIVITY_ACTION_BLOCKED,

                /* caller_uid */

                callingUid,
@@ -1677,47 +1707,44 @@ public class ActivityTaskSupervisor implements RecentTasks.Callbacks { 
                /* bal_code */

                -1

        );

            }

        }

        task.mTransitionController.requestCloseTransitionIfNeeded(task);

        task.mInRemoveTask = true;

        try {

            task.removeActivities(reason, false /* excludingTaskOverlay */);

            cleanUpRemovedTaskLocked(task, killProcess, removeFromRecents);

            mService.getLockTaskController().clearLockedTask(task);

            mService.getTaskChangeNotificationController().notifyTaskStackChanged();

            if (task.isPersistable) {

                mService.notifyTaskPersisterLocked(null, true);

            }

            if (wouldBlockActivitySwitchIgnoringFlags) {



        boolean restrictActivitySwitch = ActivitySecurityModelFeatureFlags

                .shouldRestrictActivitySwitch(callingUid)

                && shouldBlockActivitySwitchIfFeatureEnabled;



        PackageManager pm = mService.mContext.getPackageManager();

        String callingPackage = pm.getNameForUid(callingUid);

        final CharSequence callingLabel;

        if (callingPackage == null) {

            callingPackage = String.valueOf(callingUid);

            callingLabel = callingPackage;

        } else {

            callingLabel = getApplicationLabel(pm, callingPackage);

        }



        if (ActivitySecurityModelFeatureFlags.shouldShowToast(callingUid)) {

                    UiThread.getHandler().post(() -> Toast.makeText(mService.mContext,

                            (restrictActivitySwitch

                                    ? "Returning home due to "

                                    : "Would return home due to ")

                                    + ActivitySecurityModelFeatureFlags.DOC_LINK,

                            Toast.LENGTH_LONG).show());

            Toast toast = Toast.makeText(mService.mContext,

                    (ActivitySecurityModelFeatureFlags.DOC_LINK

                            + (restrictActivitySwitch

                            ? "returned home due to "

                            : "would return home due to ")

                            + callingLabel),

                    Toast.LENGTH_LONG);

            UiThread.getHandler().post(toast::show);

        }



        // If the activity switch should be restricted, return home rather than the

        // previously top task, to prevent users from being confused which app they're

        // viewing

        if (restrictActivitySwitch) {

                    Slog.w(TAG, "[ASM] Return to home as source uid: " + callingUid

            Slog.w(TAG, "[ASM] Return to home as source: " + callingPackage

                    + " is not on top of task t: " + task);

                    task.getTaskDisplayArea().moveHomeActivityToTop("taskRemoved");

            displayArea.moveHomeActivityToTop("taskRemoved");

        } else {

                    Slog.i(TAG, "[ASM] Would return to home as source uid: " + callingUid

            Slog.i(TAG, "[ASM] Would return to home as source: " + callingPackage

                    + " is not on top of task t: " + task);

        }

    }

        } finally {

            task.mInRemoveTask = false;

        }

    }



    /**

     *  For the purpose of ASM, ‘Top UID” for a task is defined as an activity UID
@@ -1779,6 +1806,16 @@ public class ActivityTaskSupervisor implements RecentTasks.Callbacks { 
        return topActivity.allowCrossUidActivitySwitchFromBelow(uid);

    }



    static CharSequence getApplicationLabel(PackageManager pm, String packageName) {

        try {

            ApplicationInfo launchedFromPackageInfo = pm.getApplicationInfo(

                    packageName, PackageManager.ApplicationInfoFlags.of(0));

            return pm.getApplicationLabel(launchedFromPackageInfo);

        } catch (PackageManager.NameNotFoundException e) {

            return packageName;

        }

    }



    void cleanUpRemovedTaskLocked(Task task, boolean killProcess, boolean removeFromRecents) {

        if (removeFromRecents) {

            mRecentTasks.remove(task);