// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/extensions/external_registry_loader_win.h"
#include <memory>
#include <utility>
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/files/scoped_file.h"
#include "base/functional/bind.h"
#include "base/functional/callback.h"
#include "base/metrics/histogram_macros.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task/sequenced_task_runner.h"
#include "base/task/thread_pool.h"
#include "base/time/time.h"
#include "base/values.h"
#include "base/version.h"
#include "base/win/registry.h"
#include "chrome/browser/extensions/external_provider_impl.h"
#include "components/crx_file/id_util.h"
#include "content/public/browser/browser_task_traits.h"
#include "content/public/browser/browser_thread.h"
using content::BrowserThread;
namespace {
// The Registry subkey that contains information about external extensions.
const wchar_t kRegistryExtensions[] = L"Software\\Google\\Chrome\\Extensions";
// Registry value of the key that defines the installation parameter.
const wchar_t kRegistryExtensionInstallParam[] = L"install_parameter";
// Registry value of the key that defines the path to the .crx file.
const wchar_t kRegistryExtensionPath[] = L"path";
// Registry value of that key that defines the current version of the .crx file.
const wchar_t kRegistryExtensionVersion[] = L"version";
// Registry value of the key that defines an external update URL.
const wchar_t kRegistryExtensionUpdateUrl[] = L"update_url";
bool CanOpenFileForReading(const base::FilePath& path) {
// Note: Because this ScopedFILE is used on the stack and not passed around
// threads/sequences, this method doesn't require callers to run on tasks with
// BLOCK_SHUTDOWN. SKIP_ON_SHUTDOWN is enough and safe because it guarantees
// that if a task starts, it will always finish, and will block shutdown at
// that point.
base::ScopedFILE file_handle(base::OpenFile(path, "rb"));
return file_handle.get() != NULL;
}
std::string MakePrefName(const std::string& extension_id,
const std::string& pref_name) {
return base::StringPrintf("%s.%s", extension_id.c_str(), pref_name.c_str());
}
} // namespace
namespace extensions {
ExternalRegistryLoader::ExternalRegistryLoader()
: attempted_watching_registry_(false) {}
ExternalRegistryLoader::~ExternalRegistryLoader() {}
void ExternalRegistryLoader::StartLoading() {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
GetOrCreateTaskRunner()->PostTask(
FROM_HERE,
base::BindOnce(&ExternalRegistryLoader::LoadOnBlockingThread, this));
}
base::Value::Dict ExternalRegistryLoader::LoadPrefsOnBlockingThread() {
base::Value::Dict prefs;
// A map of IDs, to weed out duplicates between HKCU and HKLM.
std::set<std::wstring> keys;
base::win::RegistryKeyIterator iterator_machine_key(
HKEY_LOCAL_MACHINE,
kRegistryExtensions,
KEY_WOW64_32KEY);
for (; iterator_machine_key.Valid(); ++iterator_machine_key)
keys.insert(iterator_machine_key.Name());
base::win::RegistryKeyIterator iterator_user_key(
HKEY_CURRENT_USER, kRegistryExtensions);
for (; iterator_user_key.Valid(); ++iterator_user_key)
keys.insert(iterator_user_key.Name());
// Iterate over the keys found, first trying HKLM, then HKCU, as per Windows
// policy conventions. We only fall back to HKCU if the HKLM key cannot be
// opened, not if the data within the key is invalid, for example.
for (auto it = keys.begin(); it != keys.end(); ++it) {
base::win::RegKey key;
std::wstring key_path = kRegistryExtensions;
key_path.append(L"\\");
key_path.append(*it);
if (key.Open(HKEY_LOCAL_MACHINE,
key_path.c_str(),
KEY_READ | KEY_WOW64_32KEY) != ERROR_SUCCESS &&
key.Open(HKEY_CURRENT_USER, key_path.c_str(), KEY_READ) !=
ERROR_SUCCESS) {
LOG(ERROR) << "Unable to read registry key at path (HKLM & HKCU): "
<< key_path << ".";
continue;
}
std::string id = base::ToLowerASCII(base::WideToASCII(*it));
if (!crx_file::id_util::IdIsValid(id)) {
LOG(ERROR) << "Invalid id value " << id
<< " for key " << key_path << ".";
continue;
}
std::wstring extension_dist_id;
if (key.ReadValue(kRegistryExtensionInstallParam, &extension_dist_id) ==
ERROR_SUCCESS) {
prefs.SetByDottedPath(
MakePrefName(id, ExternalProviderImpl::kInstallParam),
base::WideToASCII(extension_dist_id));
}
// If there is an update URL present, copy it to prefs and ignore
// path and version keys for this entry.
std::wstring extension_update_url;
if (key.ReadValue(kRegistryExtensionUpdateUrl, &extension_update_url)
== ERROR_SUCCESS) {
prefs.SetByDottedPath(
MakePrefName(id, ExternalProviderImpl::kExternalUpdateUrl),
base::WideToASCII(extension_update_url));
continue;
}
std::wstring extension_path_str;
if (key.ReadValue(kRegistryExtensionPath, &extension_path_str)
!= ERROR_SUCCESS) {
// TODO(erikkay): find a way to get this into about:extensions
LOG(ERROR) << "Missing value " << kRegistryExtensionPath
<< " for key " << key_path << ".";
continue;
}
base::FilePath extension_path(extension_path_str);
if (!extension_path.IsAbsolute()) {
LOG(ERROR) << "File path " << extension_path_str
<< " needs to be absolute in key "
<< key_path;
continue;
}
if (!base::PathExists(extension_path)) {
LOG(ERROR) << "File " << extension_path_str
<< " for key " << key_path
<< " does not exist or is not readable.";
continue;
}
if (!CanOpenFileForReading(extension_path)) {
LOG(ERROR) << "File " << extension_path_str
<< " for key " << key_path << " can not be read. "
<< "Check that users who should have the extension "
<< "installed have permission to read it.";
continue;
}
std::wstring extension_version;
if (key.ReadValue(kRegistryExtensionVersion, &extension_version)
!= ERROR_SUCCESS) {
// TODO(erikkay): find a way to get this into about:extensions
LOG(ERROR) << "Missing value " << kRegistryExtensionVersion
<< " for key " << key_path << ".";
continue;
}
base::Version version(base::WideToASCII(extension_version));
if (!version.IsValid()) {
LOG(ERROR) << "Invalid version value " << extension_version
<< " for key " << key_path << ".";
continue;
}
prefs.SetByDottedPath(
MakePrefName(id, ExternalProviderImpl::kExternalVersion),
base::WideToASCII(extension_version));
prefs.SetByDottedPath(MakePrefName(id, ExternalProviderImpl::kExternalCrx),
base::AsString16(extension_path_str));
prefs.SetByDottedPath(
MakePrefName(id, ExternalProviderImpl::kMayBeUntrusted), true);
}
return prefs;
}
void ExternalRegistryLoader::LoadOnBlockingThread() {
DCHECK(task_runner_);
DCHECK(task_runner_->RunsTasksInCurrentSequence());
base::TimeTicks start_time = base::TimeTicks::Now();
base::Value::Dict prefs = LoadPrefsOnBlockingThread();
LOCAL_HISTOGRAM_TIMES("Extensions.ExternalRegistryLoaderWin",
base::TimeTicks::Now() - start_time);
content::GetUIThreadTaskRunner({})->PostTask(
FROM_HERE,
base::BindOnce(
&ExternalRegistryLoader::CompleteLoadAndStartWatchingRegistry, this,
std::move(prefs)));
}
void ExternalRegistryLoader::CompleteLoadAndStartWatchingRegistry(
base::Value::Dict prefs) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
LoadFinished(std::move(prefs));
// Attempt to watch registry if we haven't already.
if (attempted_watching_registry_)
return;
LONG result = ERROR_SUCCESS;
if ((result = hklm_key_.Create(HKEY_LOCAL_MACHINE, kRegistryExtensions,
KEY_NOTIFY | KEY_WOW64_32KEY)) ==
ERROR_SUCCESS) {
base::win::RegKey::ChangeCallback callback =
base::BindOnce(&ExternalRegistryLoader::OnRegistryKeyChanged,
base::Unretained(this), base::Unretained(&hklm_key_));
hklm_key_.StartWatching(std::move(callback));
} else {
LOG(WARNING) << "Error observing HKLM: " << result;
}
if ((result = hkcu_key_.Create(HKEY_CURRENT_USER, kRegistryExtensions,
KEY_NOTIFY)) == ERROR_SUCCESS) {
base::win::RegKey::ChangeCallback callback =
base::BindOnce(&ExternalRegistryLoader::OnRegistryKeyChanged,
base::Unretained(this), base::Unretained(&hkcu_key_));
hkcu_key_.StartWatching(std::move(callback));
} else {
LOG(WARNING) << "Error observing HKCU: " << result;
}
attempted_watching_registry_ = true;
}
void ExternalRegistryLoader::OnRegistryKeyChanged(base::win::RegKey* key) {
// |OnRegistryKeyChanged| is removed as an observer when the ChangeCallback is
// called, so we need to re-register.
key->StartWatching(
base::BindOnce(&ExternalRegistryLoader::OnRegistryKeyChanged,
base::Unretained(this), base::Unretained(key)));
GetOrCreateTaskRunner()->PostTask(
FROM_HERE,
base::BindOnce(&ExternalRegistryLoader::UpatePrefsOnBlockingThread,
this));
}
scoped_refptr<base::SequencedTaskRunner>
ExternalRegistryLoader::GetOrCreateTaskRunner() {
if (!task_runner_.get()) {
task_runner_ = base::ThreadPool::CreateSequencedTaskRunner(
{// Requires I/O for registry.
base::MayBlock(),
// Inherit priority.
base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN});
}
return task_runner_;
}
void ExternalRegistryLoader::UpatePrefsOnBlockingThread() {
DCHECK(task_runner_);
DCHECK(task_runner_->RunsTasksInCurrentSequence());
base::TimeTicks start_time = base::TimeTicks::Now();
base::Value::Dict prefs = LoadPrefsOnBlockingThread();
LOCAL_HISTOGRAM_TIMES("Extensions.ExternalRegistryLoaderWinUpdate",
base::TimeTicks::Now() - start_time);
content::GetUIThreadTaskRunner({})->PostTask(
FROM_HERE, base::BindOnce(&ExternalRegistryLoader::OnUpdated, this,
std::move(prefs)));
}
} // namespace extensions
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