Merge cherrypicks of ['googleplex-android-review.googlesource.com/29287881']... (a5fbddcb) · Commits · e / os / android_frameworks_base

packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java

+68 −11

Original line number	Diff line number	Diff line
		@@ -16,8 +16,6 @@

		package com.android.externalstorage;

		import static java.util.regex.Pattern.CASE_INSENSITIVE;

		import android.annotation.NonNull;
		import android.annotation.Nullable;
		import android.app.usage.StorageStatsManager;
		@@ -61,12 +59,15 @@ import java.io.FileDescriptor;
		import java.io.FileNotFoundException;
		import java.io.IOException;
		import java.io.PrintWriter;
		import java.nio.file.Files;
		import java.nio.file.Paths;
		import java.util.Arrays;
		import java.util.Collections;
		import java.util.List;
		import java.util.Locale;
		import java.util.Objects;
		import java.util.UUID;
		import java.util.regex.Pattern;
		import java.util.stream.Collectors;

		/**
		* Presents content of the shared (a.k.a. "external") storage.
		@@ -89,12 +90,9 @@ public class ExternalStorageProvider extends FileSystemProvider {
		private static final Uri BASE_URI =
		new Uri.Builder().scheme(ContentResolver.SCHEME_CONTENT).authority(AUTHORITY).build();

		/**
		* Regex for detecting {@code /Android/data/}, {@code /Android/obb/} and
		* {@code /Android/sandbox/} along with all their subdirectories and content.
		*/
		private static final Pattern PATTERN_RESTRICTED_ANDROID_SUBTREES =
		Pattern.compile("^Android/(?:data\|obb\|sandbox)(?:/.+)?", CASE_INSENSITIVE);
		private static final String PRIMARY_EMULATED_STORAGE_PATH = "/storage/emulated/";

		private static final String STORAGE_PATH = "/storage/";

		private static final String[] DEFAULT_ROOT_PROJECTION = new String[] {
		Root.COLUMN_ROOT_ID, Root.COLUMN_FLAGS, Root.COLUMN_ICON, Root.COLUMN_TITLE,
		@@ -308,10 +306,69 @@ public class ExternalStorageProvider extends FileSystemProvider {
		return false;
		}

		final String path = getPathFromDocId(documentId);
		return PATTERN_RESTRICTED_ANDROID_SUBTREES.matcher(path).matches();
		try {
		final RootInfo root = getRootFromDocId(documentId);
		final String canonicalPath = getPathFromDocId(documentId);
		return isRestrictedPath(root.rootId, canonicalPath);
		} catch (Exception e) {
		return true;
		}
		}

		/**
		* Based on the given root id and path, we restrict path access if file is Android/data or
		* Android/obb or Android/sandbox or one of their subdirectories.
		*
		* @param canonicalPath of the file
		* @return true if path is restricted
		*/
		private boolean isRestrictedPath(String rootId, String canonicalPath) {
		if (rootId == null \|\| canonicalPath == null) {
		return true;
		}

		final String rootPath;
		if (rootId.equalsIgnoreCase(ROOT_ID_PRIMARY_EMULATED)) {
		// Creates "/storage/emulated/<user-id>"
		rootPath = PRIMARY_EMULATED_STORAGE_PATH + UserHandle.myUserId();
		} else {
		// Creates "/storage/<volume-uuid>"
		rootPath = STORAGE_PATH + rootId;
		}
		List<java.nio.file.Path> restrictedPathList = Arrays.asList(
		Paths.get(rootPath, "Android", "data"),
		Paths.get(rootPath, "Android", "obb"),
		Paths.get(rootPath, "Android", "sandbox"));
		// We need to identify restricted parent paths which actually exist on the device
		List<java.nio.file.Path> validRestrictedPathsToCheck = restrictedPathList.stream().filter(
		Files::exists).collect(Collectors.toList());

		boolean isRestricted = false;
		java.nio.file.Path filePathToCheck = Paths.get(rootPath, canonicalPath);
		try {
		while (filePathToCheck != null) {
		for (java.nio.file.Path restrictedPath : validRestrictedPathsToCheck) {
		if (Files.isSameFile(restrictedPath, filePathToCheck)) {
		isRestricted = true;
		Log.v(TAG, "Restricting access for path: " + filePathToCheck);
		break;
		}
		}
		if (isRestricted) {
		break;
		}

		filePathToCheck = filePathToCheck.getParent();
		}
		} catch (Exception e) {
		Log.w(TAG, "Error in checking file equality check.", e);
		isRestricted = true;
		}

		return isRestricted;
		}


		/**
		* Check that the directory is the root of storage or blocked file from tree.
		* <p>