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// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Most of this code is copied from:
// src/chrome/browser/policy/asynchronous_policy_loader.{h,cc}
#include "remoting/host/policy_watcher.h"
#include <memory>
#include <utility>
#include "base/compiler_specific.h"
#include "base/files/file_path.h"
#include "base/functional/bind.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/notimplemented.h"
#include "base/task/single_thread_task_runner.h"
#include "base/values.h"
#include "build/branding_buildflags.h"
#include "build/build_config.h"
#include "components/policy/core/common/async_policy_loader.h"
#include "components/policy/core/common/async_policy_provider.h"
#include "components/policy/core/common/policy_namespace.h"
#include "components/policy/core/common/policy_service_impl.h"
#include "components/policy/core/common/schema.h"
#include "components/policy/core/common/schema_registry.h"
#include "components/policy/policy_constants.h"
#include "remoting/base/port_range.h"
#if !defined(NDEBUG)
#include "base/json/json_reader.h"
#endif
#if BUILDFLAG(IS_WIN)
#include "components/policy/core/common/policy_loader_win.h"
#elif BUILDFLAG(IS_APPLE)
#include "base/apple/foundation_util.h"
#include "base/strings/sys_string_conversions.h"
#include "components/policy/core/common/policy_loader_mac.h"
#include "components/policy/core/common/preferences_mac.h"
#elif BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
#include "components/policy/core/common/config_dir_policy_loader.h"
#include "components/policy/core/common/policy_paths.h" // nogncheck
#endif
namespace remoting {
namespace key = ::policy::key;
namespace {
#if BUILDFLAG(IS_WIN)
#if BUILDFLAG(GOOGLE_CHROME_BRANDING)
constexpr wchar_t kChromePolicyKey[] = L"SOFTWARE\\Policies\\Google\\Chrome";
#else
constexpr wchar_t kChromePolicyKey[] = L"SOFTWARE\\Policies\\Chromium";
#endif // BUILDFLAG(GOOGLE_CHROME_BRANDING)
#endif // BUILDFLAG(IS_WIN)
// Copies all policy values from one dictionary to another, using values from
// |default_values| if they are not set in |from|.
base::Value::Dict CopyValuesAndAddDefaults(
const base::Value::Dict& from,
const base::Value::Dict& default_values) {
base::Value::Dict to(default_values.Clone());
for (auto i : default_values) {
// If the policy isn't in |from|, use the default.
const base::Value* value = from.FindByDottedPath(i.first);
if (!value) {
continue;
}
CHECK(value->type() == i.second.type() || value->is_none() ||
i.second.is_none());
to.Set(i.first, value->Clone());
}
return to;
}
policy::PolicyNamespace GetPolicyNamespace() {
return policy::PolicyNamespace(policy::POLICY_DOMAIN_CHROME, std::string());
}
std::unique_ptr<policy::SchemaRegistry> CreateSchemaRegistry() {
// TODO(lukasza): Schema below should ideally only cover Chromoting-specific
// policies (expecting perf and maintanability improvement, but no functional
// impact).
policy::Schema schema = policy::Schema::Wrap(policy::GetChromeSchemaData());
auto schema_registry = std::make_unique<policy::SchemaRegistry>();
schema_registry->RegisterComponent(GetPolicyNamespace(), schema);
return schema_registry;
}
base::Value::Dict CopyChromotingPoliciesIntoDictionary(
const policy::PolicyMap& current) {
const char kPolicyNameSubstring[] = "RemoteAccessHost";
const char kClassManagementEnabled[] = "ClassManagementEnabled";
base::Value::Dict policy_dict;
for (const auto& entry : current) {
const std::string& key = entry.first;
// |value_unsafe| is used due to multiple policy types being handled.
const base::Value* value = entry.second.value_unsafe();
// Copying only Chromoting-specific policies helps avoid false alarms
// raised by NormalizePolicies below (such alarms shutdown the host).
// A special exception is the ClassManagementEnabled policy. This is used
// by education to allow teacher/student view-only CRD connections.
// TODO(lukasza): Removing this somewhat brittle filtering will be possible
// after having separate, Chromoting-specific schema.
if ((key.find(kPolicyNameSubstring) != std::string::npos) ||
(key == kClassManagementEnabled)) {
policy_dict.Set(key, value->Clone());
}
}
return policy_dict;
}
// Takes a dictionary containing only 1) recognized policy names and 2)
// well-typed policy values and further verifies policy contents.
bool VerifyWellformedness(const base::Value::Dict& changed_policies) {
// Verify UdpPortRange policy.
const std::string* udp_port_range_string =
changed_policies.FindString(policy::key::kRemoteAccessHostUdpPortRange);
PortRange udp_port_range;
if (udp_port_range_string) {
if (!PortRange::Parse(*udp_port_range_string, &udp_port_range)) {
return false;
}
}
// Report that all the policies were well-formed.
return true;
}
} // namespace
void PolicyWatcher::StartWatching(
const PolicyUpdatedCallback& policy_updated_callback,
const PolicyErrorCallback& policy_error_callback) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
DCHECK(!policy_updated_callback.is_null());
DCHECK(!policy_error_callback.is_null());
DCHECK(policy_updated_callback_.is_null());
policy_updated_callback_ = policy_updated_callback;
policy_error_callback_ = policy_error_callback;
// Listen for future policy changes.
policy_service_->AddObserver(policy::POLICY_DOMAIN_CHROME, this);
// Process current policy state.
if (policy_service_->IsInitializationComplete(policy::POLICY_DOMAIN_CHROME)) {
OnPolicyServiceInitialized(policy::POLICY_DOMAIN_CHROME);
}
}
base::Value::Dict PolicyWatcher::GetEffectivePolicies() {
return effective_policies_.Clone();
}
base::Value::Dict PolicyWatcher::GetPlatformPolicies() {
return platform_policies_.Clone();
}
base::Value::Dict PolicyWatcher::GetDefaultPolicies() {
base::Value::Dict result;
result.Set(key::kRemoteAccessHostFirewallTraversal, true);
result.Set(key::kRemoteAccessHostClientDomainList, base::Value::List());
result.Set(key::kRemoteAccessHostDomainList, base::Value::List());
result.Set(key::kRemoteAccessHostAllowRelayedConnection, true);
result.Set(key::kRemoteAccessHostUdpPortRange, "");
result.Set(key::kRemoteAccessHostClipboardSizeBytes, -1);
result.Set(key::kRemoteAccessHostAllowRemoteSupportConnections, true);
#if BUILDFLAG(IS_CHROMEOS)
result.Set(key::kRemoteAccessHostAllowEnterpriseRemoteSupportConnections,
true);
result.Set(key::kRemoteAccessHostAllowEnterpriseFileTransfer, false);
result.Set(key::kClassManagementEnabled, "disabled");
#endif
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_MAC)
result.Set(key::kRemoteAccessHostMatchUsername, false);
#endif
#if !BUILDFLAG(IS_CHROMEOS)
result.Set(key::kRemoteAccessHostRequireCurtain, false);
result.Set(key::kRemoteAccessHostAllowClientPairing, true);
result.Set(key::kRemoteAccessHostAllowGnubbyAuth, true);
result.Set(key::kRemoteAccessHostAllowFileTransfer, true);
result.Set(key::kRemoteAccessHostAllowUrlForwarding, true);
result.Set(key::kRemoteAccessHostEnableUserInterface, true);
result.Set(key::kRemoteAccessHostAllowRemoteAccessConnections, true);
result.Set(key::kRemoteAccessHostMaximumSessionDurationMinutes, 0);
result.Set(key::kRemoteAccessHostAllowPinAuthentication, base::Value());
#endif
#if BUILDFLAG(IS_WIN)
result.Set(key::kRemoteAccessHostAllowUiAccessForRemoteAssistance, false);
#endif
return result;
}
void PolicyWatcher::SignalPolicyError() {
effective_policies_.clear();
platform_policies_.clear();
policy_error_callback_.Run();
}
PolicyWatcher::PolicyWatcher(
policy::PolicyService* policy_service,
std::unique_ptr<policy::PolicyService> owned_policy_service,
std::unique_ptr<policy::ConfigurationPolicyProvider> owned_policy_provider,
std::unique_ptr<policy::SchemaRegistry> owned_schema_registry)
: default_values_(GetDefaultPolicies()),
owned_schema_registry_(std::move(owned_schema_registry)),
owned_policy_provider_(std::move(owned_policy_provider)),
owned_policy_service_(std::move(owned_policy_service)),
policy_service_(policy_service) {
DCHECK(policy_service_);
DCHECK(owned_schema_registry_);
}
PolicyWatcher::~PolicyWatcher() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
// Stop observing |policy_service_| if StartWatching() has been called.
if (!policy_updated_callback_.is_null()) {
policy_service_->RemoveObserver(policy::POLICY_DOMAIN_CHROME, this);
}
if (owned_policy_provider_) {
owned_policy_provider_->Shutdown();
}
}
const policy::Schema* PolicyWatcher::GetPolicySchema() const {
return owned_schema_registry_->schema_map()->GetSchema(GetPolicyNamespace());
}
bool PolicyWatcher::NormalizePolicies(base::Value* policy_dict) {
// Allowing unrecognized policy names allows presence of
// 1) comments (i.e. JSON of the form: { "_comment": "blah", ... }),
// 2) policies intended for future/newer versions of the host,
// 3) policies not supported on all OS-s (i.e. RemoteAccessHostMatchUsername
// is not supported on Windows and therefore policy_templates.json omits
// schema for this policy on this particular platform).
auto strategy = policy::SCHEMA_ALLOW_UNKNOWN;
DCHECK(policy_dict->GetIfDict());
policy::PolicyErrorPath path;
std::string error;
bool changed = false;
const policy::Schema* schema = GetPolicySchema();
if (schema->Normalize(policy_dict, strategy, &path, &error, &changed)) {
if (changed) {
LOG(WARNING) << "Unknown (unrecognized or unsupported) policy at: "
<< policy::ErrorPathToString("toplevel", path) << ": "
<< error;
}
HandleDeprecatedPolicies(&policy_dict->GetDict());
return true;
} else {
LOG(ERROR) << "Invalid policy contents at: "
<< policy::ErrorPathToString("toplevel", path) << ": " << error;
return false;
}
}
void PolicyWatcher::HandleDeprecatedPolicies(base::Value::Dict* dict) {
// RemoteAccessHostDomain
if (dict->Find(policy::key::kRemoteAccessHostDomain)) {
if (!dict->Find(policy::key::kRemoteAccessHostDomainList)) {
const std::string* domain =
dict->FindString(policy::key::kRemoteAccessHostDomain);
if (domain && !domain->empty()) {
base::Value::List list;
list.Append(*domain);
dict->Set(policy::key::kRemoteAccessHostDomainList, std::move(list));
}
}
dict->Remove(policy::key::kRemoteAccessHostDomain);
}
// RemoteAccessHostClientDomain
if (const std::string* domain =
dict->FindString(policy::key::kRemoteAccessHostClientDomain)) {
if (!dict->Find(policy::key::kRemoteAccessHostClientDomainList)) {
if (!domain->empty()) {
base::Value::List list;
list.Append(*domain);
dict->Set(policy::key::kRemoteAccessHostClientDomainList,
std::move(list));
}
}
dict->Remove(policy::key::kRemoteAccessHostClientDomain);
}
}
base::Value::Dict PolicyWatcher::StoreNewAndReturnChangedPolicies(
base::Value::Dict new_policies) {
// Find the changed policies.
base::Value::Dict changed_policies;
for (auto iter : new_policies) {
base::Value* old_policy = effective_policies_.FindByDottedPath(iter.first);
if (!old_policy || *old_policy != iter.second) {
changed_policies.Set(iter.first, iter.second.Clone());
}
}
// Save the new policies.
std::swap(effective_policies_, new_policies);
return changed_policies;
}
void PolicyWatcher::OnPolicyUpdated(const policy::PolicyNamespace& ns,
const policy::PolicyMap& previous,
const policy::PolicyMap& current) {
base::Value new_policies(CopyChromotingPoliciesIntoDictionary(current));
// Check for mistyped values and get rid of unknown policies.
if (!NormalizePolicies(&new_policies)) {
SignalPolicyError();
return;
}
platform_policies_ = new_policies.GetDict().Clone();
// Use default values for any missing policies.
base::Value::Dict filled_policies =
CopyValuesAndAddDefaults(new_policies.GetDict(), default_values_);
// Limit reporting to only the policies that were changed.
base::Value::Dict changed_policies =
StoreNewAndReturnChangedPolicies(std::move(filled_policies));
if (changed_policies.empty()) {
return;
}
// Verify that we are calling the callback with valid policies.
if (!VerifyWellformedness(changed_policies)) {
SignalPolicyError();
return;
}
// Notify our client of the changed policies.
policy_updated_callback_.Run(std::move(changed_policies));
}
void PolicyWatcher::OnPolicyServiceInitialized(policy::PolicyDomain domain) {
policy::PolicyNamespace ns = GetPolicyNamespace();
const policy::PolicyMap& current = policy_service_->GetPolicies(ns);
OnPolicyUpdated(ns, current, current);
#if BUILDFLAG(IS_WIN)
WatchForRegistryChanges();
#endif
}
std::unique_ptr<PolicyWatcher> PolicyWatcher::CreateFromPolicyLoader(
std::unique_ptr<policy::AsyncPolicyLoader> async_policy_loader) {
std::unique_ptr<policy::SchemaRegistry> schema_registry =
CreateSchemaRegistry();
auto policy_provider = std::make_unique<policy::AsyncPolicyProvider>(
schema_registry.get(), std::move(async_policy_loader));
policy_provider->Init(schema_registry.get());
policy::PolicyServiceImpl::Providers providers;
providers.push_back(policy_provider.get());
std::unique_ptr<policy::PolicyServiceImpl> policy_service =
std::make_unique<policy::PolicyServiceImpl>(std::move(providers));
policy::PolicyService* borrowed_policy_service = policy_service.get();
return base::WrapUnique(new PolicyWatcher(
borrowed_policy_service, std::move(policy_service),
std::move(policy_provider), std::move(schema_registry)));
}
std::unique_ptr<PolicyWatcher> PolicyWatcher::CreateWithPolicyService(
policy::PolicyService* policy_service) {
DCHECK(policy_service);
return base::WrapUnique(new PolicyWatcher(policy_service, nullptr, nullptr,
CreateSchemaRegistry()));
}
#if BUILDFLAG(IS_WIN)
void PolicyWatcher::WatchForRegistryChanges() {
if (!policy_key_.Valid()) {
auto open_result =
policy_key_.Open(HKEY_LOCAL_MACHINE, kChromePolicyKey, KEY_NOTIFY);
if (open_result != ERROR_SUCCESS) {
LOG(WARNING) << "Failed to open Chrome policy registry key due to error: "
<< open_result;
return;
}
}
// base::Unretained is sound as |policy_key_| is destroyed before we start
// tearing down the various policy service members. Once the PolicyService has
// finished refreshing the policy list, we need to set up our watcher again as
// it only fires once.
auto watch_result = policy_key_.StartWatching(
base::BindOnce(&policy::PolicyService::RefreshPolicies,
base::Unretained(policy_service_),
base::BindOnce(&PolicyWatcher::WatchForRegistryChanges,
base::Unretained(this)),
policy::PolicyFetchReason::kCrdHostPolicyWatcher));
if (!watch_result) {
LOG(WARNING) << "Failed to register for Chrome policy registry key changes";
policy_key_.Close();
}
}
#endif
std::unique_ptr<PolicyWatcher> PolicyWatcher::CreateWithTaskRunner(
const scoped_refptr<base::SingleThreadTaskRunner>& file_task_runner,
policy::ManagementService* management_service) {
// Create platform-specific PolicyLoader. Always read the Chrome policies
// (even on Chromium) so that policy enforcement can't be bypassed by running
// Chromium.
std::unique_ptr<policy::AsyncPolicyLoader> policy_loader;
#if BUILDFLAG(IS_WIN)
policy_loader = std::make_unique<policy::PolicyLoaderWin>(
file_task_runner, management_service, kChromePolicyKey);
#elif BUILDFLAG(IS_APPLE)
#if BUILDFLAG(GOOGLE_CHROME_BRANDING)
// Explicitly watch the "com.google.Chrome" bundle ID, no matter what this
// app's bundle ID actually is. All channels of Chrome should obey the same
// policies.
CFStringRef bundle_id = CFSTR("com.google.Chrome");
#else
base::apple::ScopedCFTypeRef<CFStringRef> bundle_id_scoper =
base::SysUTF8ToCFStringRef(base::apple::BaseBundleID());
CFStringRef bundle_id = bundle_id_scoper.get();
#endif // BUILDFLAG(GOOGLE_CHROME_BRANDING)
policy_loader = std::make_unique<policy::PolicyLoaderMac>(
file_task_runner,
policy::PolicyLoaderMac::GetManagedPolicyPath(bundle_id),
std::make_unique<MacPreferences>(), bundle_id);
#elif BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
policy_loader = std::make_unique<policy::ConfigDirPolicyLoader>(
file_task_runner, base::FilePath(policy::kPolicyPath),
policy::POLICY_SCOPE_MACHINE);
#elif BUILDFLAG(IS_ANDROID)
NOTIMPLEMENTED();
policy::PolicyServiceImpl::Providers providers;
std::unique_ptr<policy::PolicyService> owned_policy_service(
new policy::PolicyServiceImpl(providers));
return base::WrapUnique(new PolicyWatcher(owned_policy_service.get(),
std::move(owned_policy_service),
nullptr, CreateSchemaRegistry()));
#elif BUILDFLAG(IS_CHROMEOS)
NOTREACHED() << "CreateWithPolicyService() should be used on ChromeOS.";
#else
#error OS that is not yet supported by PolicyWatcher code.
#endif
return PolicyWatcher::CreateFromPolicyLoader(std::move(policy_loader));
}
std::unique_ptr<PolicyWatcher> PolicyWatcher::CreateFromPolicyLoaderForTesting(
std::unique_ptr<policy::AsyncPolicyLoader> async_policy_loader) {
return CreateFromPolicyLoader(std::move(async_policy_loader));
}
} // namespace remoting
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