Revert "Revert "Skip restore of read-only directories"" (9e7c309c) · Commits · e / os / android_frameworks_base

services/backup/java/com/android/server/backup/restore/FullRestoreEngine.java

+65 −0

Original line number	Diff line number	Diff line
		@@ -25,8 +25,10 @@ import static com.android.server.backup.UserBackupManagerService.OP_TYPE_RESTORE
		import static com.android.server.backup.UserBackupManagerService.SHARED_BACKUP_AGENT_PACKAGE;
		import static com.android.server.backup.internal.BackupHandler.MSG_RESTORE_OPERATION_TIMEOUT;

		import android.annotation.NonNull;
		import android.app.ApplicationThreadConstants;
		import android.app.IBackupAgent;
		import android.app.backup.BackupAgent;
		import android.app.backup.BackupManager;
		import android.app.backup.FullBackup;
		import android.app.backup.IBackupManagerMonitor;
		@@ -39,10 +41,12 @@ import android.content.pm.Signature;
		import android.os.ParcelFileDescriptor;
		import android.os.RemoteException;
		import android.provider.Settings;
		import android.system.OsConstants;
		import android.text.TextUtils;
		import android.util.Slog;

		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.annotations.VisibleForTesting;
		import com.android.server.LocalServices;
		import com.android.server.backup.BackupAgentTimeoutParameters;
		import com.android.server.backup.BackupRestoreTask;
		@@ -56,6 +60,7 @@ import com.android.server.backup.utils.FullBackupRestoreObserverUtils;
		import com.android.server.backup.utils.RestoreUtils;
		import com.android.server.backup.utils.TarBackupReader;

		import java.io.File;
		import java.io.FileOutputStream;
		import java.io.IOException;
		import java.io.InputStream;
		@@ -132,6 +137,7 @@ public class FullRestoreEngine extends RestoreEngine {
		@GuardedBy("mPipesLock")
		private boolean mPipesClosed;
		private final BackupEligibilityRules mBackupEligibilityRules;
		private FileMetadata mReadOnlyParent = null;

		public FullRestoreEngine(UserBackupManagerService backupManagerService,
		BackupRestoreTask monitorTask, IFullBackupRestoreObserver observer,
		@@ -154,6 +160,21 @@ public class FullRestoreEngine extends RestoreEngine {
		mBackupEligibilityRules = backupEligibilityRules;
		}

		@VisibleForTesting
		FullRestoreEngine() {
		mIsAdbRestore = false;
		mAllowApks = false;
		mEphemeralOpToken = 0;
		mUserId = 0;
		mBackupEligibilityRules = null;
		mAgentTimeoutParameters = null;
		mBuffer = null;
		mBackupManagerService = null;
		mMonitor = null;
		mMonitorTask = null;
		mOnlyPackage = null;
		}

		public IBackupAgent getAgent() {
		return mAgent;
		}
		@@ -393,6 +414,11 @@ public class FullRestoreEngine extends RestoreEngine {
		okay = false;
		}

		if (shouldSkipReadOnlyDir(info)) {
		// b/194894879: We don't support restore of read-only dirs.
		okay = false;
		}

		// At this point we have an agent ready to handle the full
		// restore data as well as a pipe for sending data to
		// that agent. Tell the agent to start reading from the
		@@ -569,6 +595,45 @@ public class FullRestoreEngine extends RestoreEngine {
		return (info != null);
		}

		boolean shouldSkipReadOnlyDir(FileMetadata info) {
		if (isValidParent(mReadOnlyParent, info)) {
		// This file has a read-only parent directory, we shouldn't
		// restore it.
		return true;
		} else {
		// We're now in a different branch of the file tree, update the parent
		// value.
		if (isReadOnlyDir(info)) {
		// Current directory is read-only. Remember it so that we can skip all
		// of its contents.
		mReadOnlyParent = info;
		Slog.w(TAG, "Skipping restore of " + info.path + " and its contents as "
		+ "read-only dirs are currently not supported.");
		return true;
		} else {
		mReadOnlyParent = null;
		}
		}

		return false;
		}

		private static boolean isValidParent(FileMetadata parentDir, @NonNull FileMetadata childDir) {
		return parentDir != null
		&& childDir.packageName.equals(parentDir.packageName)
		&& childDir.domain.equals(parentDir.domain)
		&& childDir.path.startsWith(getPathWithTrailingSeparator(parentDir.path));
		}

		private static String getPathWithTrailingSeparator(String path) {
		return path.endsWith(File.separator) ? path : path + File.separator;
		}

		private static boolean isReadOnlyDir(FileMetadata file) {
		// Check if owner has 'write' bit in the file's mode value (see 'man -7 inode' for details).
		return file.type == BackupAgent.TYPE_DIRECTORY && (file.mode & OsConstants.S_IWUSR) == 0;
		}

		private void setUpPipes() throws IOException {
		synchronized (mPipesLock) {
		mPipes = ParcelFileDescriptor.createPipe();

services/tests/servicestests/src/com/android/server/backup/restore/FullRestoreEngineTest.java

0 → 100644

+150 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2022 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package com.android.server.backup.restore;

		import static com.google.common.truth.Truth.assertWithMessage;

		import android.app.backup.BackupAgent;
		import android.platform.test.annotations.Presubmit;
		import android.system.OsConstants;

		import androidx.test.runner.AndroidJUnit4;

		import com.android.server.backup.FileMetadata;

		import org.junit.Before;
		import org.junit.Test;
		import org.junit.runner.RunWith;

		@Presubmit
		@RunWith(AndroidJUnit4.class)
		public class FullRestoreEngineTest {
		private static final String DEFAULT_PACKAGE_NAME = "package";
		private static final String DEFAULT_DOMAIN_NAME = "domain";
		private static final String NEW_PACKAGE_NAME = "new_package";
		private static final String NEW_DOMAIN_NAME = "new_domain";

		private FullRestoreEngine mRestoreEngine;

		@Before
		public void setUp() {
		mRestoreEngine = new FullRestoreEngine();
		}

		@Test
		public void shouldSkipReadOnlyDir_skipsAllReadonlyDirsAndTheirChildren() {
		// Create the file tree.
		TestFile[] testFiles = new TestFile[] {
		TestFile.dir("root"),
		TestFile.file("root/auth_token"),
		TestFile.dir("root/media"),
		TestFile.file("root/media/picture1.png"),
		TestFile.file("root/push_token.txt"),
		TestFile.dir("root/read-only-dir-1").markReadOnly().expectSkipped(),
		TestFile.dir("root/read-only-dir-1/writable-subdir").expectSkipped(),
		TestFile.file("root/read-only-dir-1/writable-subdir/writable-file").expectSkipped(),
		TestFile.dir("root/read-only-dir-1/writable-subdir/read-only-subdir-2")
		.markReadOnly().expectSkipped(),
		TestFile.file("root/read-only-dir-1/writable-file").expectSkipped(),
		TestFile.file("root/random-stuff.txt"),
		TestFile.dir("root/database"),
		TestFile.file("root/database/users.db"),
		TestFile.dir("root/read-only-dir-2").markReadOnly().expectSkipped(),
		TestFile.file("root/read-only-dir-2/writable-file-1").expectSkipped(),
		TestFile.file("root/read-only-dir-2/writable-file-2").expectSkipped(),
		};

		assertCorrectItemsAreSkipped(testFiles);
		}

		@Test
		public void shouldSkipReadOnlyDir_onlySkipsChildrenUnderTheSamePackage() {
		TestFile[] testFiles = new TestFile[]{
		TestFile.dir("read-only-dir").markReadOnly().expectSkipped(),
		TestFile.file("read-only-dir/file").expectSkipped(),
		TestFile.file("read-only-dir/file-from-different-package")
		.setPackage(NEW_PACKAGE_NAME),
		};

		assertCorrectItemsAreSkipped(testFiles);
		}

		@Test
		public void shouldSkipReadOnlyDir_onlySkipsChildrenUnderTheSameDomain() {
		TestFile[] testFiles = new TestFile[]{
		TestFile.dir("read-only-dir").markReadOnly().expectSkipped(),
		TestFile.file("read-only-dir/file").expectSkipped(),
		TestFile.file("read-only-dir/file-from-different-domain")
		.setDomain(NEW_DOMAIN_NAME),
		};

		assertCorrectItemsAreSkipped(testFiles);
		}

		private void assertCorrectItemsAreSkipped(TestFile[] testFiles) {
		// Verify all directories marked with .expectSkipped are skipped.
		for (TestFile testFile : testFiles) {
		boolean actualExcluded = mRestoreEngine.shouldSkipReadOnlyDir(testFile.mMetadata);
		boolean expectedExcluded = testFile.mShouldSkip;
		assertWithMessage(testFile.mMetadata.path).that(actualExcluded).isEqualTo(
		expectedExcluded);
		}
		}

		private static class TestFile {
		private final FileMetadata mMetadata;
		private boolean mShouldSkip;

		static TestFile dir(String path) {
		return new TestFile(path, BackupAgent.TYPE_DIRECTORY);
		}

		static TestFile file(String path) {
		return new TestFile(path, BackupAgent.TYPE_FILE);
		}

		TestFile markReadOnly() {
		mMetadata.mode = 0;
		return this;
		}

		TestFile expectSkipped() {
		mShouldSkip = true;
		return this;
		}

		TestFile setPackage(String packageName) {
		mMetadata.packageName = packageName;
		return this;
		}

		TestFile setDomain(String domain) {
		mMetadata.domain = domain;
		return this;
		}

		private TestFile(String path, int type) {
		FileMetadata metadata = new FileMetadata();
		metadata.path = path;
		metadata.type = type;
		metadata.packageName = DEFAULT_PACKAGE_NAME;
		metadata.domain = DEFAULT_DOMAIN_NAME;
		metadata.mode = OsConstants.S_IWUSR; // Mark as writable.
		mMetadata = metadata;
		}
		}
		}