text: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "extensions/utility/unpacker.h"
  
  #include <set>
  
  #include "base/files/file_enumerator.h"
  #include "base/files/file_util.h"
  #include "base/files/scoped_temp_dir.h"
  #include "base/i18n/rtl.h"
  #include "base/json/json_file_value_serializer.h"
  #include "base/numerics/safe_conversions.h"
  #include "base/strings/string_util.h"
  #include "base/strings/utf_string_conversions.h"
  #include "base/threading/thread.h"
  #include "base/values.h"
  #include "content/public/child/image_decoder_utils.h"
  #include "content/public/common/common_param_traits.h"
  #include "extensions/common/constants.h"
  #include "extensions/common/extension.h"
  #include "extensions/common/extension_l10n_util.h"
  #include "extensions/common/extension_utility_messages.h"
  #include "extensions/common/extensions_client.h"
  #include "extensions/common/file_util.h"
  #include "extensions/common/manifest.h"
  #include "extensions/common/manifest_constants.h"
  #include "extensions/common/manifest_handlers/default_locale_handler.h"
  #include "extensions/strings/grit/extensions_strings.h"
  #include "ipc/ipc_message_utils.h"
  #include "net/base/file_stream.h"
  #include "third_party/skia/include/core/SkBitmap.h"
  #include "third_party/zlib/google/zip.h"
  #include "ui/base/l10n/l10n_util.h"
  #include "ui/gfx/geometry/size.h"
  
  namespace extensions {
  
  namespace {
  
  namespace errors = manifest_errors;
  namespace keys = manifest_keys;
  
  // A limit to stop us passing dangerously large canvases to the browser.
  const int kMaxImageCanvas = 4096 * 4096;
  
  SkBitmap DecodeImage(const base::FilePath& path) {
    // Read the file from disk.
    std::string file_contents;
    if (!base::PathExists(path) ||
        !base::ReadFileToString(path, &file_contents)) {
      return SkBitmap();
    }
  
    // Decode the image using WebKit's image decoder.
    const unsigned char* data =
        reinterpret_cast<const unsigned char*>(file_contents.data());
    SkBitmap bitmap =
        content::DecodeImage(data, gfx::Size(), file_contents.length());
    if (bitmap.computeSize64() > kMaxImageCanvas)
      return SkBitmap();
    return bitmap;
  }
  
  bool PathContainsParentDirectory(const base::FilePath& path) {
    const base::FilePath::StringType kSeparators(base::FilePath::kSeparators);
    const base::FilePath::StringType kParentDirectory(
        base::FilePath::kParentDirectory);
    const size_t npos = base::FilePath::StringType::npos;
    const base::FilePath::StringType& value = path.value();
  
    for (size_t i = 0; i < value.length();) {
      i = value.find(kParentDirectory, i);
      if (i != npos) {
        if ((i == 0 || kSeparators.find(value[i - 1]) == npos) &&
            (i + 1 < value.length() || kSeparators.find(value[i + 1]) == npos)) {
          return true;
        }
        ++i;
      }
    }
  
    return false;
  }
  
  bool WritePickle(const IPC::Message& pickle, const base::FilePath& dest_path) {
    int size = base::checked_cast<int>(pickle.size());
    const char* data = static_cast<const char*>(pickle.data());
    int bytes_written = base::WriteFile(dest_path, data, size);
    return (bytes_written == size);
  }
  
  }  // namespace
  
  struct Unpacker::InternalData {
    DecodedImages decoded_images;
  };
  
  Unpacker::Unpacker(const base::FilePath& extension_path,
                     const std::string& extension_id,
                     Manifest::Location location,
                     int creation_flags)
      : extension_path_(extension_path),
        extension_id_(extension_id),
        location_(location),
        creation_flags_(creation_flags) {
    internal_data_.reset(new InternalData());
  }
  
  Unpacker::~Unpacker() {
  }
  
  base::DictionaryValue* Unpacker::ReadManifest() {
    base::FilePath manifest_path = temp_install_dir_.Append(kManifestFilename);
    if (!base::PathExists(manifest_path)) {
      SetError(errors::kInvalidManifest);
      return NULL;
    }
  
    JSONFileValueSerializer serializer(manifest_path);
    std::string error;
    scoped_ptr<base::Value> root(serializer.Deserialize(NULL, &error));
    if (!root.get()) {
      SetError(error);
      return NULL;
    }
  
    if (!root->IsType(base::Value::TYPE_DICTIONARY)) {
      SetError(errors::kInvalidManifest);
      return NULL;
    }
  
    return static_cast<base::DictionaryValue*>(root.release());
  }
  
  bool Unpacker::ReadAllMessageCatalogs(const std::string& default_locale) {
    base::FilePath locales_path = temp_install_dir_.Append(kLocaleFolder);
  
    // Not all folders under _locales have to be valid locales.
    base::FileEnumerator locales(locales_path, false,
                                 base::FileEnumerator::DIRECTORIES);
  
    std::set<std::string> all_locales;
    extension_l10n_util::GetAllLocales(&all_locales);
    base::FilePath locale_path;
    while (!(locale_path = locales.Next()).empty()) {
      if (extension_l10n_util::ShouldSkipValidation(locales_path, locale_path,
                                                    all_locales))
        continue;
  
      base::FilePath messages_path = locale_path.Append(kMessagesFilename);
  
      if (!ReadMessageCatalog(messages_path))
        return false;
    }
  
    return true;
  }
  
  bool Unpacker::Run() {
    DVLOG(1) << "Installing extension " << extension_path_.value();
  
    // <profile>/Extensions/CRX_INSTALL
    temp_install_dir_ = extension_path_.DirName().AppendASCII(kTempExtensionName);
  
    if (!base::CreateDirectory(temp_install_dir_)) {
      SetUTF16Error(l10n_util::GetStringFUTF16(
          IDS_EXTENSION_PACKAGE_DIRECTORY_ERROR,
          base::i18n::GetDisplayStringInLTRDirectionality(
              temp_install_dir_.LossyDisplayName())));
      return false;
    }
  
    if (!zip::Unzip(extension_path_, temp_install_dir_)) {
      SetUTF16Error(l10n_util::GetStringUTF16(IDS_EXTENSION_PACKAGE_UNZIP_ERROR));
      return false;
    }
  
    // Parse the manifest.
    parsed_manifest_.reset(ReadManifest());
    if (!parsed_manifest_.get())
      return false;  // Error was already reported.
  
    std::string error;
    scoped_refptr<Extension> extension(
        Extension::Create(temp_install_dir_, location_, *parsed_manifest_,
                          creation_flags_, extension_id_, &error));
    if (!extension.get()) {
      SetError(error);
      return false;
    }
  
    std::vector<InstallWarning> warnings;
    if (!file_util::ValidateExtension(extension.get(), &error, &warnings)) {
      SetError(error);
      return false;
    }
    extension->AddInstallWarnings(warnings);
  
    // Decode any images that the browser needs to display.
    std::set<base::FilePath> image_paths =
        ExtensionsClient::Get()->GetBrowserImagePaths(extension.get());
    for (std::set<base::FilePath>::iterator it = image_paths.begin();
         it != image_paths.end(); ++it) {
      if (!AddDecodedImage(*it))
        return false;  // Error was already reported.
    }
  
    // Parse all message catalogs (if any).
    parsed_catalogs_.reset(new base::DictionaryValue);
    if (!LocaleInfo::GetDefaultLocale(extension.get()).empty()) {
      if (!ReadAllMessageCatalogs(LocaleInfo::GetDefaultLocale(extension.get())))
        return false;  // Error was already reported.
    }
  
    return true;
  }
  
  bool Unpacker::DumpImagesToFile() {
    IPC::Message pickle;  // We use a Message so we can use WriteParam.
    IPC::WriteParam(&pickle, internal_data_->decoded_images);
  
    base::FilePath path =
        extension_path_.DirName().AppendASCII(kDecodedImagesFilename);
    if (!WritePickle(pickle, path)) {
      SetError("Could not write image data to disk.");
      return false;
    }
  
    return true;
  }
  
  bool Unpacker::DumpMessageCatalogsToFile() {
    IPC::Message pickle;
    IPC::WriteParam(&pickle, *parsed_catalogs_.get());
  
    base::FilePath path =
        extension_path_.DirName().AppendASCII(kDecodedMessageCatalogsFilename);
    if (!WritePickle(pickle, path)) {
      SetError("Could not write message catalogs to disk.");
      return false;
    }
  
    return true;
  }
  
  bool Unpacker::AddDecodedImage(const base::FilePath& path) {
    // Make sure it's not referencing a file outside the extension's subdir.
    if (path.IsAbsolute() || PathContainsParentDirectory(path)) {
      SetUTF16Error(l10n_util::GetStringFUTF16(
          IDS_EXTENSION_PACKAGE_IMAGE_PATH_ERROR,
          base::i18n::GetDisplayStringInLTRDirectionality(
              path.LossyDisplayName())));
      return false;
    }
  
    SkBitmap image_bitmap = DecodeImage(temp_install_dir_.Append(path));
    if (image_bitmap.isNull()) {
      SetUTF16Error(l10n_util::GetStringFUTF16(
          IDS_EXTENSION_PACKAGE_IMAGE_ERROR,
          base::i18n::GetDisplayStringInLTRDirectionality(
              path.BaseName().LossyDisplayName())));
      return false;
    }
  
    internal_data_->decoded_images.push_back(MakeTuple(image_bitmap, path));
    return true;
  }
  
  bool Unpacker::ReadMessageCatalog(const base::FilePath& message_path) {
    std::string error;
    JSONFileValueSerializer serializer(message_path);
    scoped_ptr<base::DictionaryValue> root(static_cast<base::DictionaryValue*>(
        serializer.Deserialize(NULL, &error)));
    if (!root.get()) {
      base::string16 messages_file = message_path.LossyDisplayName();
      if (error.empty()) {
        // If file is missing, Deserialize will fail with empty error.
        SetError(base::StringPrintf("%s %s", errors::kLocalesMessagesFileMissing,
                                    base::UTF16ToUTF8(messages_file).c_str()));
      } else {
        SetError(base::StringPrintf(
            "%s: %s", base::UTF16ToUTF8(messages_file).c_str(), error.c_str()));
      }
      return false;
    }
  
    base::FilePath relative_path;
    // message_path was created from temp_install_dir. This should never fail.
    if (!temp_install_dir_.AppendRelativePath(message_path, &relative_path)) {
      NOTREACHED();
      return false;
    }
  
    std::string dir_name = relative_path.DirName().MaybeAsASCII();
    if (dir_name.empty()) {
      NOTREACHED();
      return false;
    }
    parsed_catalogs_->Set(dir_name, root.release());
  
    return true;
  }
  
  void Unpacker::SetError(const std::string& error) {
    SetUTF16Error(base::UTF8ToUTF16(error));
  }
  
  void Unpacker::SetUTF16Error(const base::string16& error) {
    error_message_ = error;
  }
  
  }  // namespace extensions
  