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Commit 5348e683 authored by Kevin Han's avatar Kevin Han
Browse files

Lock before checking if user state is null 

If a user is removed between the user state null check and the lock, it
is possible to run into a NPE. We fix this by putting the entire user
state check inside the lock.

Bug: 211906910
Test: builds
Change-Id: I1f5f4d05f7d21db1af08e4d8cbaa48f41470dee0
parent 65094b9d

services/core/java/com/android/server/apphibernation/AppHibernationService.java

+17 −9
Original line number Diff line number Diff line
@@ -223,10 +223,10 @@ public final class AppHibernationService extends SystemService { 
                android.Manifest.permission.MANAGE_APP_HIBERNATION,

                "Caller does not have MANAGE_APP_HIBERNATION permission.");

        userId = handleIncomingUser(userId, methodName);

        synchronized (mLock) {

            if (!checkUserStatesExist(userId, methodName)) {

                return false;

            }

        synchronized (mLock) {

            final Map<String, UserLevelState> packageStates = mUserStates.get(userId);

            final UserLevelState pkgState = packageStates.get(packageName);

            if (pkgState == null) {
@@ -278,10 +278,10 @@ public final class AppHibernationService extends SystemService { 
                android.Manifest.permission.MANAGE_APP_HIBERNATION,

                "Caller does not have MANAGE_APP_HIBERNATION permission.");

        final int realUserId = handleIncomingUser(userId, methodName);

        synchronized (mLock) {

            if (!checkUserStatesExist(realUserId, methodName)) {

                return;

            }

        synchronized (mLock) {

            final Map<String, UserLevelState> packageStates = mUserStates.get(realUserId);

            final UserLevelState pkgState = packageStates.get(packageName);

            if (pkgState == null) {
@@ -365,10 +365,10 @@ public final class AppHibernationService extends SystemService { 
                android.Manifest.permission.MANAGE_APP_HIBERNATION,

                "Caller does not have MANAGE_APP_HIBERNATION permission.");

        userId = handleIncomingUser(userId, methodName);

        synchronized (mLock) {

            if (!checkUserStatesExist(userId, methodName)) {

                return hibernatingPackages;

            }

        synchronized (mLock) {

            Map<String, UserLevelState> userStates = mUserStates.get(userId);

            for (UserLevelState state : userStates.values()) {

                if (state.hibernated) {
@@ -658,6 +658,14 @@ public final class AppHibernationService extends SystemService { 
        }

    }



    /**

     * Check that user states exist.

     *

     * @param userId user to check

     * @param methodName method name that is calling. Used for logging purposes.

     * @return true if user states exist

     */

    @GuardedBy("mLock")

    private boolean checkUserStatesExist(int userId, String methodName) {

        if (!mUserManager.isUserUnlockingOrUnlocked(userId)) {

            Slog.e(TAG, String.format(