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// Copyright (c) 2009 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 "chrome/common/extensions/extension_unpacker.h"
#include "base/file_util.h"
#include "base/scoped_handle.h"
#include "base/scoped_temp_dir.h"
#include "base/string_util.h"
#include "base/thread.h"
#include "base/values.h"
#include "net/base/file_stream.h"
#include "chrome/common/common_param_traits.h"
#include "chrome/common/extensions/extension.h"
#include "chrome/common/extensions/extension_constants.h"
#include "chrome/common/json_value_serializer.h"
#include "chrome/common/notification_service.h"
#include "chrome/common/url_constants.h"
#include "chrome/common/zip.h"
#include "ipc/ipc_message_utils.h"
#include "third_party/skia/include/core/SkBitmap.h"
#include "webkit/glue/image_decoder.h"
namespace {
// The name of a temporary directory to install an extension into for
// validation before finalizing install.
const char kTempExtensionName[] = "TEMP_INSTALL";
// The file to write our decoded images to, relative to the extension_path.
const char kDecodedImagesFilename[] = "DECODED_IMAGES";
// Errors
const char* kCouldNotCreateDirectoryError =
"Could not create directory for unzipping.";
const char* kCouldNotDecodeImageError = "Could not decode theme image.";
const char* kCouldNotUnzipExtension = "Could not unzip extension.";
const char* kPathNamesMustBeAbsoluteOrLocalError =
"Path names must not be absolute or contain '..'.";
// A limit to stop us passing dangerously large canvases to the browser.
const int kMaxImageCanvas = 4096 * 4096;
} // namespace
static SkBitmap DecodeImage(const FilePath& path) {
// Read the file from disk.
std::string file_contents;
if (!file_util::PathExists(path) ||
!file_util::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());
webkit_glue::ImageDecoder decoder;
SkBitmap bitmap = decoder.Decode(data, file_contents.length());
Sk64 bitmap_size = bitmap.getSize64();
if (!bitmap_size.is32() || bitmap_size.get32() > kMaxImageCanvas)
return SkBitmap();
return bitmap;
}
static bool PathContainsParentDirectory(const FilePath& path) {
const FilePath::StringType kSeparators(FilePath::kSeparators);
const FilePath::StringType kParentDirectory(FilePath::kParentDirectory);
const size_t npos = FilePath::StringType::npos;
const 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;
}
DictionaryValue* ExtensionUnpacker::ReadManifest() {
FilePath manifest_path =
temp_install_dir_.AppendASCII(Extension::kManifestFilename);
if (!file_util::PathExists(manifest_path)) {
SetError(extension_manifest_errors::kInvalidManifest);
return NULL;
}
JSONFileValueSerializer serializer(manifest_path);
std::string error;
scoped_ptr<Value> root(serializer.Deserialize(&error));
if (!root.get()) {
SetError(error);
return NULL;
}
if (!root->IsType(Value::TYPE_DICTIONARY)) {
SetError(extension_manifest_errors::kInvalidManifest);
return NULL;
}
return static_cast<DictionaryValue*>(root.release());
}
bool ExtensionUnpacker::Run() {
LOG(INFO) << "Installing extension " << extension_path_.value();
// <profile>/Extensions/INSTALL_TEMP/<version>
temp_install_dir_ =
extension_path_.DirName().AppendASCII(kTempExtensionName);
if (!file_util::CreateDirectory(temp_install_dir_)) {
SetError(kCouldNotCreateDirectoryError);
return false;
}
if (!Unzip(extension_path_, temp_install_dir_)) {
SetError(kCouldNotUnzipExtension);
return false;
}
// Parse the manifest.
parsed_manifest_.reset(ReadManifest());
if (!parsed_manifest_.get())
return false; // Error was already reported.
// NOTE: Since the Unpacker doesn't have the extension's public_id, the
// InitFromValue is allowed to generate a temporary id for the extension.
// ANY CODE THAT FOLLOWS SHOULD NOT DEPEND ON THE CORRECT ID OF THIS
// EXTENSION.
Extension extension;
std::string error;
if (!extension.InitFromValue(*parsed_manifest_,
false,
&error)) {
SetError(error);
return false;
}
// Decode any images that the browser needs to display.
std::set<FilePath> image_paths = extension.GetBrowserImages();
for (std::set<FilePath>::iterator it = image_paths.begin();
it != image_paths.end(); ++it) {
if (!AddDecodedImage(*it))
return false; // Error was already reported.
}
return true;
}
bool ExtensionUnpacker::DumpImagesToFile() {
IPC::Message pickle; // We use a Message so we can use WriteParam.
IPC::WriteParam(&pickle, decoded_images_);
FilePath path = extension_path_.DirName().AppendASCII(kDecodedImagesFilename);
if (!file_util::WriteFile(path, static_cast<const char*>(pickle.data()),
pickle.size())) {
SetError("Could not write image data to disk.");
return false;
}
return true;
}
// static
bool ExtensionUnpacker::ReadImagesFromFile(const FilePath& extension_path,
DecodedImages* images) {
FilePath path = extension_path.AppendASCII(kDecodedImagesFilename);
std::string file_str;
if (!file_util::ReadFileToString(path, &file_str))
return false;
IPC::Message pickle(file_str.data(), file_str.size());
void* iter = NULL;
return IPC::ReadParam(&pickle, &iter, images);
}
bool ExtensionUnpacker::AddDecodedImage(const FilePath& path) {
// Make sure it's not referencing a file outside the extension's subdir.
if (path.IsAbsolute() || PathContainsParentDirectory(path)) {
SetError(kPathNamesMustBeAbsoluteOrLocalError);
return false;
}
SkBitmap image_bitmap = DecodeImage(temp_install_dir_.Append(path));
if (image_bitmap.isNull()) {
SetError(kCouldNotDecodeImageError);
return false;
}
decoded_images_.push_back(MakeTuple(image_bitmap, path));
return true;
}
void ExtensionUnpacker::SetError(const std::string &error) {
error_message_ = error;
}
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