[Multi-user] Disable backup by default in non-system users (bdb8848a) · Commits · e / os / android_frameworks_base

cmds/bmgr/src/com/android/commands/bmgr/Bmgr.java

+39 −7

Original line number	Diff line number	Diff line
		@@ -102,7 +102,17 @@ public class Bmgr {
		String op = nextArg();
		Slog.v(TAG, "Running " + op + " for user:" + userId);

		if (!isBmgrActive(userId)) {
		if (mBmgr == null) {
		System.err.println(BMGR_NOT_RUNNING_ERR);
		return;
		}

		if ("activate".equals(op)) {
		doActivateService(userId);
		return;
		}

		if (!isBackupActive(userId)) {
		return;
		}

		@@ -175,12 +185,7 @@ public class Bmgr {
		showUsage();
		}

		boolean isBmgrActive(@UserIdInt int userId) {
		if (mBmgr == null) {
		System.err.println(BMGR_NOT_RUNNING_ERR);
		return false;
		}

		boolean isBackupActive(@UserIdInt int userId) {
		try {
		if (!mBmgr.isBackupServiceActive(userId)) {
		System.err.println(BMGR_NOT_RUNNING_ERR);
		@@ -845,6 +850,27 @@ public class Bmgr {
		}
		}

		private void doActivateService(int userId) {
		String arg = nextArg();
		if (arg == null) {
		showUsage();
		return;
		}

		try {
		boolean activate = Boolean.parseBoolean(arg);
		mBmgr.setBackupServiceActive(userId, activate);
		System.out.println(
		"Backup service now "
		+ (activate ? "activated" : "deactivated")
		+ " for user "
		+ userId);
		} catch (RemoteException e) {
		System.err.println(e.toString());
		System.err.println(BMGR_NOT_RUNNING_ERR);
		}
		}

		private String nextArg() {
		if (mNextArg >= mArgs.length) {
		return null;
		@@ -880,6 +906,7 @@ public class Bmgr {
		System.err.println(" bmgr backupnow [--monitor\|--monitor-verbose] --all\|PACKAGE...");
		System.err.println(" bmgr cancel backups");
		System.err.println(" bmgr init TRANSPORT...");
		System.err.println(" bmgr activate BOOL");
		System.err.println("");
		System.err.println("The '--user' option specifies the user on which the operation is run.");
		System.err.println("It must be the first argument before the operation.");
		@@ -946,6 +973,11 @@ public class Bmgr {
		System.err.println("");
		System.err.println("The 'init' command initializes the given transports, wiping all data");
		System.err.println("from their backing data stores.");
		System.err.println("");
		System.err.println("The 'activate' command activates or deactivates the backup service.");
		System.err.println("If the argument is 'true' it will be activated, otherwise it will be");
		System.err.println("deactivated. When deactivated, the service will not be running and no");
		System.err.println("operations can be performed until activation.");
		}

		private static class BackupMonitor extends IBackupManagerMonitor.Stub {

services/backup/java/com/android/server/backup/Trampoline.java

+127 −68

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@ package com.android.server.backup;

		import static com.android.server.backup.BackupManagerService.TAG;

		import android.Manifest;
		import android.annotation.Nullable;
		import android.annotation.UserIdInt;
		import android.app.admin.DevicePolicyManager;
		@@ -41,9 +42,10 @@ import android.os.RemoteException;
		import android.os.SystemProperties;
		import android.os.Trace;
		import android.os.UserHandle;
		import android.provider.Settings;
		import android.os.UserManager;
		import android.util.Slog;

		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.util.DumpUtils;

		import java.io.File;
		@@ -75,19 +77,25 @@ import java.io.PrintWriter;
		* system user is unlocked before any other users.
		*/
		public class Trampoline extends IBackupManager.Stub {
		// When this file is present, the backup service is inactive.
		/**
		* Name of file that disables the backup service. If this file exists, then backup is disabled
		* for all users.
		*/
		private static final String BACKUP_SUPPRESS_FILENAME = "backup-suppress";

		/**
		* Name of file for non-system users that enables the backup service for the user. Backup is
		* disabled by default in non-system users.
		*/
		private static final String BACKUP_ACTIVATED_FILENAME = "backup-activated";

		// Product-level suppression of backup/restore.
		private static final String BACKUP_DISABLE_PROPERTY = "ro.backup.disable";

		private static final String BACKUP_THREAD = "backup";

		/** Values for setting {@link Settings.Global#BACKUP_MULTI_USER_ENABLED} */
		private static final int MULTI_USER_DISABLED = 0;
		private static final int MULTI_USER_ENABLED = 1;

		private final Context mContext;
		private final UserManager mUserManager;

		private final boolean mGlobalDisable;
		// Lock to write backup suppress files.
		@@ -104,20 +112,13 @@ public class Trampoline extends IBackupManager.Stub {
		mHandlerThread = new HandlerThread(BACKUP_THREAD, Process.THREAD_PRIORITY_BACKGROUND);
		mHandlerThread.start();
		mHandler = new Handler(mHandlerThread.getLooper());
		mUserManager = UserManager.get(context);
		}

		protected boolean isBackupDisabled() {
		return SystemProperties.getBoolean(BACKUP_DISABLE_PROPERTY, false);
		}

		private boolean isMultiUserEnabled() {
		return Settings.Global.getInt(
		mContext.getContentResolver(),
		Settings.Global.BACKUP_MULTI_USER_ENABLED,
		MULTI_USER_DISABLED)
		== MULTI_USER_ENABLED;
		}

		protected int binderGetCallingUserId() {
		return Binder.getCallingUserHandle().getIdentifier();
		}
		@@ -126,21 +127,65 @@ public class Trampoline extends IBackupManager.Stub {
		return Binder.getCallingUid();
		}

		protected File getSuppressFileForUser(int userId) {
		return new File(UserBackupManagerFiles.getBaseStateDir(userId),
		/** Stored in the system user's directory. */
		protected File getSuppressFileForSystemUser() {
		return new File(UserBackupManagerFiles.getBaseStateDir(UserHandle.USER_SYSTEM),
		BACKUP_SUPPRESS_FILENAME);
		}

		protected void createBackupSuppressFileForUser(int userId) throws IOException {
		synchronized (mStateLock) {
		getSuppressFileForUser(userId).getParentFile().mkdirs();
		getSuppressFileForUser(userId).createNewFile();
		/** Stored in the system user's directory and the file is indexed by the user it refers to. */
		protected File getActivatedFileForNonSystemUser(int userId) {
		return new File(UserBackupManagerFiles.getBaseStateDir(UserHandle.USER_SYSTEM),
		BACKUP_ACTIVATED_FILENAME + "-" + userId);
		}

		private void createFile(File file) throws IOException {
		if (file.exists()) {
		return;
		}

		file.getParentFile().mkdirs();
		if (!file.createNewFile()) {
		Slog.w(TAG, "Failed to create file " + file.getPath());
		}
		}

		private void deleteFile(File file) {
		if (!file.exists()) {
		return;
		}

		if (!file.delete()) {
		Slog.w(TAG, "Failed to delete file " + file.getPath());
		}
		}

		/**
		* Deactivates the backup service for user {@code userId}. If this is the system user, it
		* creates a suppress file which disables backup for all users. If this is a non-system user, it
		* only deactivates backup for that user by deleting its activate file.
		*/
		@GuardedBy("mStateLock")
		private void deactivateBackupForUserLocked(int userId) throws IOException {
		if (userId == UserHandle.USER_SYSTEM) {
		createFile(getSuppressFileForSystemUser());
		} else {
		deleteFile(getActivatedFileForNonSystemUser(userId));
		}
		}

		private void deleteBackupSuppressFileForUser(int userId) {
		if (!getSuppressFileForUser(userId).delete()) {
		Slog.w(TAG, "Failed deleting backup suppressed file for user: " + userId);
		/**
		* Enables the backup service for user {@code userId}. If this is the system user, it deletes
		* the suppress file. If this is a non-system user, it creates the user's activate file. Note,
		* deleting the suppress file does not automatically enable backup for non-system users, they
		* need their own activate file in order to participate in the service.
		*/
		@GuardedBy("mStateLock")
		private void activateBackupForUserLocked(int userId) throws IOException {
		if (userId == UserHandle.USER_SYSTEM) {
		deleteFile(getSuppressFileForSystemUser());
		} else {
		createFile(getActivatedFileForNonSystemUser(userId));
		}
		}

		@@ -148,24 +193,31 @@ public class Trampoline extends IBackupManager.Stub {
		// admin (device owner or profile owner).
		private boolean isUserReadyForBackup(int userId) {
		return mService != null && mService.getServiceUsers().get(userId) != null
		&& !isBackupSuppressedForUser(userId);
		&& isBackupActivatedForUser(userId);
		}

		private boolean isBackupSuppressedForUser(int userId) {
		// If backup is disabled for system user, it's disabled for all other users on device.
		if (getSuppressFileForUser(UserHandle.USER_SYSTEM).exists()) {
		return true;
		}
		if (userId != UserHandle.USER_SYSTEM) {
		return getSuppressFileForUser(userId).exists();
		}
		/**
		* Backup is activated for the system user if the suppress file does not exist. Backup is
		* activated for non-system users if the suppress file does not exist AND the user's activated
		* file exists.
		*/
		private boolean isBackupActivatedForUser(int userId) {
		if (getSuppressFileForSystemUser().exists()) {
		return false;
		}

		return userId == UserHandle.USER_SYSTEM
		\|\| getActivatedFileForNonSystemUser(userId).exists();
		}

		protected Context getContext() {
		return mContext;
		}

		protected UserManager getUserManager() {
		return mUserManager;
		}

		protected BackupManagerService createBackupManagerService() {
		return new BackupManagerService(mContext, this, mHandlerThread);
		}
		@@ -198,23 +250,17 @@ public class Trampoline extends IBackupManager.Stub {

		/**
		* Called from {@link BackupManagerService.Lifecycle} when a user {@code userId} is unlocked.
		* Starts the backup service for this user if it's the system user or if the service supports
		* multi-user. Offloads work onto the handler thread {@link #mHandlerThread} to keep unlock time
		* low.
		* Starts the backup service for this user if backup is active for this user. Offloads work onto
		* the handler thread {@link #mHandlerThread} to keep unlock time low.
		*/
		void unlockUser(int userId) {
		if (userId != UserHandle.USER_SYSTEM && !isMultiUserEnabled()) {
		Slog.i(TAG, "Multi-user disabled, cannot start service for user: " + userId);
		return;
		}

		postToHandler(() -> startServiceForUser(userId));
		}

		private void startServiceForUser(int userId) {
		// We know that the user is unlocked here because it is called from setBackupServiceActive
		// and unlockUser which have these guarantees. So we can check if the file exists.
		if (mService != null && !isBackupSuppressedForUser(userId)) {
		if (mService != null && isBackupActivatedForUser(userId)) {
		Slog.i(TAG, "Starting service for user: " + userId);
		mService.startServiceForUser(userId);
		}
		@@ -225,11 +271,6 @@ public class Trampoline extends IBackupManager.Stub {
		* Offloads work onto the handler thread {@link #mHandlerThread} to keep stopping time low.
		*/
		void stopUser(int userId) {
		if (userId != UserHandle.USER_SYSTEM && !isMultiUserEnabled()) {
		Slog.i(TAG, "Multi-user disabled, cannot stop service for user: " + userId);
		return;
		}

		postToHandler(
		() -> {
		if (mService != null) {
		@@ -240,30 +281,39 @@ public class Trampoline extends IBackupManager.Stub {
		}

		/**
		* Only privileged callers should be changing the backup state. This method only acts on {@link
		* UserHandle#USER_SYSTEM} and is a no-op if passed non-system users. Deactivating backup in the
		* system user also deactivates backup in all users.
		*
		* This call will only work if the calling {@code userID} is unlocked.
		* The system user and managed profiles can only be acted on by callers in the system or root
		* processes. Other users can be acted on by callers who have both android.permission.BACKUP and
		* android.permission.INTERACT_ACROSS_USERS_FULL permissions.
		*/
		public void setBackupServiceActive(int userId, boolean makeActive) {
		private void enforcePermissionsOnUser(int userId) throws SecurityException {
		boolean isRestrictedUser =
		userId == UserHandle.USER_SYSTEM
		\|\| getUserManager().getUserInfo(userId).isManagedProfile();

		if (isRestrictedUser) {
		int caller = binderGetCallingUid();
		if (caller != Process.SYSTEM_UID && caller != Process.ROOT_UID) {
		throw new SecurityException("No permission to configure backup activity");
		}

		if (mGlobalDisable) {
		Slog.i(TAG, "Backup service not supported");
		return;
		} else {
		mContext.enforceCallingOrSelfPermission(
		Manifest.permission.BACKUP, "No permission to configure backup activity");
		mContext.enforceCallingOrSelfPermission(
		Manifest.permission.INTERACT_ACROSS_USERS_FULL,
		"No permission to configure backup activity");
		}

		if (userId != UserHandle.USER_SYSTEM) {
		Slog.i(TAG, "Cannot set backup service activity for non-system user: " + userId);
		return;
		}

		if (makeActive == isBackupServiceActive(userId)) {
		Slog.i(TAG, "No change in backup service activity");
		/**
		* Only privileged callers should be changing the backup state. Deactivating backup in the
		* system user also deactivates backup in all users. We are not guaranteed that {@code userId}
		* is unlocked at this point yet, so handle both cases.
		*/
		public void setBackupServiceActive(int userId, boolean makeActive) {
		enforcePermissionsOnUser(userId);

		if (mGlobalDisable) {
		Slog.i(TAG, "Backup service not supported");
		return;
		}

		@@ -273,12 +323,21 @@ public class Trampoline extends IBackupManager.Stub {
		if (mService == null) {
		mService = createBackupManagerService();
		}
		deleteBackupSuppressFileForUser(userId);
		try {
		activateBackupForUserLocked(userId);
		} catch (IOException e) {
		Slog.e(TAG, "Unable to persist backup service activity");
		}

		// If the user is unlocked, we can start the backup service for it. Otherwise we
		// will start the service when the user is unlocked as part of its unlock callback.
		if (getUserManager().isUserUnlocked(userId)) {
		startServiceForUser(userId);
		}
		} else {
		try {
		//TODO(b/121198006): what if this throws an exception?
		createBackupSuppressFileForUser(userId);
		deactivateBackupForUserLocked(userId);
		} catch (IOException e) {
		Slog.e(TAG, "Unable to persist backup service inactivity");
		}

services/tests/servicestests/src/com/android/server/backup/TrampolineTest.java

+165 −125

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