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Commit 44e8debe authored by Felka Chang's avatar Felka Chang
Browse files

Prevent Idmapdaemon from failing set system property 

During the shutdown mode, system property is not allowed to be set.
To set system property is used by either starting or stopping
IdmapDaemon.

To start IdmapDaemon may be during the shutdown mode. In this
situation, it triggers NullPointerException because IdmapDaemon is
not started and mService is null. This patch handles this kind of
RuntimeException, logs the error and prevents NPE.

Test: TID="CtsAppSecurityHostTestCases"; \
    atest OverlayDeviceTests \
    OverlayHostTests \
    OverlayRemountedTest \
    ${TID}:android.appsecurity.cts.OverlayHostTest

Test: http://ab/I12600010009296086

Bug: 214011992
Bug: 212776174
Change-Id: I1820f00473be423d08738a6045925bb38a71d541
parent 35eef324

services/core/java/com/android/server/om/IdmapDaemon.java

+101 −18
Original line number Diff line number Diff line
@@ -37,13 +37,14 @@ import com.android.server.FgThread; 


import java.io.File;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

import java.util.concurrent.TimeoutException;

import java.util.concurrent.atomic.AtomicInteger;



/**

 * To prevent idmap2d from continuously running, the idmap daemon will terminate after 10

 * seconds without a transaction.

 * To prevent idmap2d from continuously running, the idmap daemon will terminate after 10 seconds

 * without a transaction.

 **/

class IdmapDaemon {

    // The amount of time in milliseconds to wait after a transaction to the idmap service is made
@@ -67,11 +68,14 @@ class IdmapDaemon { 
     * to the service is open.

     **/

    private class Connection implements AutoCloseable {

        @Nullable

        private final IIdmap2 mIdmap2;

        private boolean mOpened = true;



        private Connection() {

        private Connection(IIdmap2 idmap2) {

            synchronized (mIdmapToken) {

                mOpenedCount.incrementAndGet();

                mIdmap2 = idmap2;

            }

        }
@@ -102,6 +106,11 @@ class IdmapDaemon { 
                }, mIdmapToken, SERVICE_TIMEOUT_MS);

            }

        }



        @Nullable

        public IIdmap2 getIdmap2() {

            return mIdmap2;

        }

    }



    static IdmapDaemon getInstance() {
@@ -115,14 +124,29 @@ class IdmapDaemon { 
            @Nullable String overlayName, int policies, boolean enforce, int userId)

            throws TimeoutException, RemoteException {

        try (Connection c = connect()) {

            return mService.createIdmap(targetPath, overlayPath, TextUtils.emptyIfNull(overlayName),

            final IIdmap2 idmap2 = c.getIdmap2();

            if (idmap2 == null) {

                Slog.w(TAG, "idmap2d service is not ready for createIdmap(\"" + targetPath

                        + "\", \"" + overlayPath + "\", \"" + overlayName + "\", " + policies + ", "

                        + enforce + ", " + userId + ")");

                return null;

            }



            return idmap2.createIdmap(targetPath, overlayPath, TextUtils.emptyIfNull(overlayName),

                    policies, enforce, userId);

        }

    }



    boolean removeIdmap(String overlayPath, int userId) throws TimeoutException, RemoteException {

        try (Connection c = connect()) {

            return mService.removeIdmap(overlayPath, userId);

            final IIdmap2 idmap2 = c.getIdmap2();

            if (idmap2 == null) {

                Slog.w(TAG, "idmap2d service is not ready for removeIdmap(\"" + overlayPath

                        + "\", " + userId + ")");

                return false;

            }



            return idmap2.removeIdmap(overlayPath, userId);

        }

    }
@@ -130,14 +154,29 @@ class IdmapDaemon { 
            @Nullable String overlayName, int policies, boolean enforce, int userId)

            throws Exception {

        try (Connection c = connect()) {

            return mService.verifyIdmap(targetPath, overlayPath, TextUtils.emptyIfNull(overlayName),

            final IIdmap2 idmap2 = c.getIdmap2();

            if (idmap2 == null) {

                Slog.w(TAG, "idmap2d service is not ready for verifyIdmap(\"" + targetPath

                        + "\", \"" + overlayPath + "\", \"" + overlayName + "\", " + policies + ", "

                        + enforce + ", " + userId + ")");

                return false;

            }



            return idmap2.verifyIdmap(targetPath, overlayPath, TextUtils.emptyIfNull(overlayName),

                    policies, enforce, userId);

        }

    }



    boolean idmapExists(String overlayPath, int userId) {

        try (Connection c = connect()) {

            return new File(mService.getIdmapPath(overlayPath, userId)).isFile();

            final IIdmap2 idmap2 = c.getIdmap2();

            if (idmap2 == null) {

                Slog.w(TAG, "idmap2d service is not ready for idmapExists(\"" + overlayPath

                        + "\", " + userId + ")");

                return false;

            }



            return new File(idmap2.getIdmapPath(overlayPath, userId)).isFile();

        } catch (Exception e) {

            Slog.wtf(TAG, "failed to check if idmap exists for " + overlayPath, e);

            return false;
@@ -146,7 +185,13 @@ class IdmapDaemon { 


    FabricatedOverlayInfo createFabricatedOverlay(@NonNull FabricatedOverlayInternal overlay) {

        try (Connection c = connect()) {

            return mService.createFabricatedOverlay(overlay);

            final IIdmap2 idmap2 = c.getIdmap2();

            if (idmap2 == null) {

                Slog.w(TAG, "idmap2d service is not ready for createFabricatedOverlay()");

                return null;

            }



            return idmap2.createFabricatedOverlay(overlay);

        } catch (Exception e) {

            Slog.wtf(TAG, "failed to fabricate overlay " + overlay, e);

            return null;
@@ -155,7 +200,14 @@ class IdmapDaemon { 


    boolean deleteFabricatedOverlay(@NonNull String path) {

        try (Connection c = connect()) {

            return mService.deleteFabricatedOverlay(path);

            final IIdmap2 idmap2 = c.getIdmap2();

            if (idmap2 == null) {

                Slog.w(TAG, "idmap2d service is not ready for deleteFabricatedOverlay(\"" + path

                        + "\")");

                return false;

            }



            return idmap2.deleteFabricatedOverlay(path);

        } catch (Exception e) {

            Slog.wtf(TAG, "failed to delete fabricated overlay '" + path + "'", e);

            return false;
@@ -164,10 +216,18 @@ class IdmapDaemon { 


    synchronized List<FabricatedOverlayInfo> getFabricatedOverlayInfos() {

        final ArrayList<FabricatedOverlayInfo> allInfos = new ArrayList<>();

        try (Connection c = connect()) {

            mService.acquireFabricatedOverlayIterator();

        Connection c = null;

        try {

            c = connect();

            final IIdmap2 service = c.getIdmap2();

            if (service == null) {

                Slog.w(TAG, "idmap2d service is not ready for getFabricatedOverlayInfos()");

                return Collections.emptyList();

            }



            service.acquireFabricatedOverlayIterator();

            List<FabricatedOverlayInfo> infos;

            while (!(infos = mService.nextFabricatedOverlayInfos()).isEmpty()) {

            while (!(infos = service.nextFabricatedOverlayInfos()).isEmpty()) {

                allInfos.addAll(infos);

            }

            return allInfos;
@@ -175,17 +235,26 @@ class IdmapDaemon { 
            Slog.wtf(TAG, "failed to get all fabricated overlays", e);

        } finally {

            try {

                mService.releaseFabricatedOverlayIterator();

                if (c.getIdmap2() != null) {

                    c.getIdmap2().releaseFabricatedOverlayIterator();

                }

            } catch (RemoteException e) {

                // ignore

            }

            c.close();

        }

        return allInfos;

    }



    String dumpIdmap(@NonNull String overlayPath) {

        try (Connection c = connect()) {

            String dump = mService.dumpIdmap(overlayPath);

            final IIdmap2 service = c.getIdmap2();

            if (service == null) {

                final String dumpText = "idmap2d service is not ready for dumpIdmap()";

                Slog.w(TAG, dumpText);

                return dumpText;

            }

            String dump = service.dumpIdmap(overlayPath);

            return TextUtils.nullIfEmpty(dump);

        } catch (Exception e) {

            Slog.wtf(TAG, "failed to dump idmap", e);
@@ -193,8 +262,16 @@ class IdmapDaemon { 
        }

    }



    @Nullable

    private IBinder getIdmapService() throws TimeoutException, RemoteException {

        try {

            SystemService.start(IDMAP_DAEMON);

        } catch (RuntimeException e) {

            if (e.getMessage().contains("failed to set system property")) {

                Slog.w(TAG, "Failed to enable idmap2 daemon", e);

                return null;

            }

        }



        final long endMillis = SystemClock.elapsedRealtime() + SERVICE_CONNECT_TIMEOUT_MS;

        while (SystemClock.elapsedRealtime() <= endMillis) {
@@ -226,17 +303,23 @@ class IdmapDaemon { 
        }

    }



    @NonNull

    private Connection connect() throws TimeoutException, RemoteException {

        synchronized (mIdmapToken) {

            FgThread.getHandler().removeCallbacksAndMessages(mIdmapToken);

            if (mService != null) {

                // Not enough time has passed to stop the idmap service. Reuse the existing

                // interface.

                return new Connection();

                return new Connection(mService);

            }



            IBinder binder = getIdmapService();

            if (binder == null) {

                return new Connection(null);

            }



            mService = IIdmap2.Stub.asInterface(getIdmapService());

            return new Connection();

            mService = IIdmap2.Stub.asInterface(binder);

            return new Connection(mService);

        }

    }

}