| /* |
| * Copyright (C) 2017 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 android.telephony.mbms; |
| |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| import android.content.ContentProvider; |
| import android.content.ContentResolver; |
| import android.content.ContentValues; |
| import android.content.Context; |
| import android.content.SharedPreferences; |
| import android.content.pm.PackageManager; |
| import android.content.pm.ProviderInfo; |
| import android.database.Cursor; |
| import android.net.Uri; |
| import android.os.Bundle; |
| import android.os.ParcelFileDescriptor; |
| |
| import java.io.File; |
| import java.io.FileNotFoundException; |
| import java.io.IOException; |
| import java.util.Objects; |
| |
| /** |
| * @hide |
| */ |
| public class MbmsTempFileProvider extends ContentProvider { |
| public static final String DEFAULT_TOP_LEVEL_TEMP_DIRECTORY = "androidMbmsTempFileRoot"; |
| public static final String TEMP_FILE_ROOT_PREF_FILE_NAME = "MbmsTempFileRootPrefs"; |
| public static final String TEMP_FILE_ROOT_PREF_NAME = "mbms_temp_file_root"; |
| |
| private String mAuthority; |
| private Context mContext; |
| |
| @Override |
| public boolean onCreate() { |
| return true; |
| } |
| |
| @Override |
| public Cursor query(@NonNull Uri uri, @Nullable String[] projection, |
| @Nullable String selection, @Nullable String[] selectionArgs, |
| @Nullable String sortOrder) { |
| throw new UnsupportedOperationException("No querying supported"); |
| } |
| |
| @Override |
| public String getType(@NonNull Uri uri) { |
| // EMBMS temp files can contain arbitrary content. |
| return "application/octet-stream"; |
| } |
| |
| @Override |
| public Uri insert(@NonNull Uri uri, @Nullable ContentValues values) { |
| throw new UnsupportedOperationException("No inserting supported"); |
| } |
| |
| @Override |
| public int delete(@NonNull Uri uri, @Nullable String selection, |
| @Nullable String[] selectionArgs) { |
| throw new UnsupportedOperationException("No deleting supported"); |
| } |
| |
| @Override |
| public int update(@NonNull Uri uri, @Nullable ContentValues values, @Nullable String |
| selection, @Nullable String[] selectionArgs) { |
| throw new UnsupportedOperationException("No updating supported"); |
| } |
| |
| @Override |
| public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException { |
| // ContentProvider has already checked granted permissions |
| final File file = getFileForUri(mContext, mAuthority, uri); |
| final int fileMode = ParcelFileDescriptor.parseMode(mode); |
| return ParcelFileDescriptor.open(file, fileMode); |
| } |
| |
| @Override |
| public void attachInfo(Context context, ProviderInfo info) { |
| super.attachInfo(context, info); |
| |
| // Sanity check our security |
| if (info.exported) { |
| throw new SecurityException("Provider must not be exported"); |
| } |
| if (!info.grantUriPermissions) { |
| throw new SecurityException("Provider must grant uri permissions"); |
| } |
| |
| mAuthority = info.authority; |
| mContext = context; |
| } |
| |
| public static Uri getUriForFile(Context context, String authority, File file) { |
| // Get the canonical path of the temp file |
| String filePath; |
| try { |
| filePath = file.getCanonicalPath(); |
| } catch (IOException e) { |
| throw new IllegalArgumentException("Could not get canonical path for file " + file); |
| } |
| |
| // Make sure the temp file is contained in the temp file directory as configured in the |
| // manifest |
| File tempFileDir = getEmbmsTempFileDir(context); |
| if (!MbmsUtils.isContainedIn(tempFileDir, file)) { |
| throw new IllegalArgumentException("File " + file + " is not contained in the temp " + |
| "file directory, which is " + tempFileDir); |
| } |
| |
| // Get the canonical path of the temp file directory |
| String tempFileDirPath; |
| try { |
| tempFileDirPath = tempFileDir.getCanonicalPath(); |
| } catch (IOException e) { |
| throw new RuntimeException( |
| "Could not get canonical path for temp file root dir " + tempFileDir); |
| } |
| |
| // Start at first char of path under temp file directory |
| String pathFragment; |
| if (tempFileDirPath.endsWith("/")) { |
| pathFragment = filePath.substring(tempFileDirPath.length()); |
| } else { |
| pathFragment = filePath.substring(tempFileDirPath.length() + 1); |
| } |
| |
| String encodedPath = Uri.encode(pathFragment); |
| return new Uri.Builder().scheme(ContentResolver.SCHEME_CONTENT) |
| .authority(authority).encodedPath(encodedPath).build(); |
| } |
| |
| public static File getFileForUri(Context context, String authority, Uri uri) |
| throws FileNotFoundException { |
| if (!ContentResolver.SCHEME_CONTENT.equals(uri.getScheme())) { |
| throw new IllegalArgumentException("Uri must have scheme content"); |
| } |
| if (!Objects.equals(authority, uri.getAuthority())) { |
| throw new IllegalArgumentException("Uri does not have a matching authority: " + |
| authority + ", " + uri.getAuthority()); |
| } |
| |
| String relPath = Uri.decode(uri.getEncodedPath()); |
| File file; |
| File tempFileDir; |
| |
| try { |
| tempFileDir = getEmbmsTempFileDir(context).getCanonicalFile(); |
| file = new File(tempFileDir, relPath).getCanonicalFile(); |
| } catch (IOException e) { |
| throw new FileNotFoundException("Could not resolve paths"); |
| } |
| |
| if (!file.getPath().startsWith(tempFileDir.getPath())) { |
| throw new SecurityException("Resolved path jumped beyond configured root"); |
| } |
| |
| return file; |
| } |
| |
| /** |
| * Returns a File for the directory used to store temp files for this app |
| */ |
| public static File getEmbmsTempFileDir(Context context) { |
| SharedPreferences prefs = context.getSharedPreferences(TEMP_FILE_ROOT_PREF_FILE_NAME, 0); |
| String storedTempFileRoot = prefs.getString(TEMP_FILE_ROOT_PREF_NAME, null); |
| try { |
| if (storedTempFileRoot != null) { |
| return new File(storedTempFileRoot).getCanonicalFile(); |
| } else { |
| return new File(context.getFilesDir(), DEFAULT_TOP_LEVEL_TEMP_DIRECTORY) |
| .getCanonicalFile(); |
| } |
| } catch (IOException e) { |
| throw new RuntimeException("Unable to canonicalize temp file root path " + e); |
| } |
| } |
| } |