Policy implementation for encryptfs to ext4 migration strategy

chrome/browser/chromeos/arc/arc_util.cc

Index: chrome/browser/chromeos/arc/arc_util.cc
diff --git a/chrome/browser/chromeos/arc/arc_util.cc b/chrome/browser/chromeos/arc/arc_util.cc
index 2930f79effc8b36e4756eb71ed5ed2b961b3747a..17383d8a614b342e856e4564f508cb11137f3566 100644
--- a/chrome/browser/chromeos/arc/arc_util.cc
+++ b/chrome/browser/chromeos/arc/arc_util.cc
@@ -9,18 +9,26 @@
 #include <set>
 
 #include "base/callback.h"
+#include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
+#include "base/optional.h"
 #include "base/sys_info.h"
 #include "base/task_scheduler/post_task.h"
 #include "base/threading/thread_restrictions.h"
+#include "base/values.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/browser_process_platform_part.h"
 #include "chrome/browser/chromeos/arc/arc_session_manager.h"
 #include "chrome/browser/chromeos/login/user_flow.h"
 #include "chrome/browser/chromeos/login/users/chrome_user_manager.h"
+#include "chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h"
+#include "chrome/browser/chromeos/policy/proto/chrome_device_policy.pb.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/pref_names.h"
+#include "chromeos/chromeos_switches.h"
 #include "components/arc/arc_util.h"
 #include "components/prefs/pref_service.h"
 #include "components/user_manager/known_user.h"
@@ -54,6 +62,11 @@ bool g_arc_blocked_due_to_incomaptible_filesystem_for_testing = false;
 base::LazyInstance<std::set<AccountId>>::DestructorAtExit
     g_known_compatible_users = LAZY_INSTANCE_INITIALIZER;
 
+// This flag is set the first time the check if migration to ext4 is allowed,
+// and remains unchanged after that.
+// TODO(igorcov): Remove this after migration. crbug.com/725493
+base::Optional<bool> g_is_arc_migration_allowed;
+
 // Returns whether ARC can run on the filesystem mounted at |path|.
 // This function should run only on threads where IO operations are allowed.
 bool IsArcCompatibleFilesystem(const base::FilePath& path) {
@@ -94,6 +107,33 @@ void StoreCompatibilityCheckResult(const AccountId& account_id,
   callback.Run();
 }
 
+bool IsArcMigrationAllowedInternal() {
+  // If the device is not managed, then the migration allowed.
+  if (!g_browser_process->platform_part()
+           ->browser_policy_connector_chromeos()
+           ->IsEnterpriseManaged()) {
+    return true;
+  }
+
+  const auto* const command_line = base::CommandLine::ForCurrentProcess();
+  // If the command line flag is missing, the migration for this type of
+  // device is allowed regardless of the policy data.
+  if (!command_line->HasSwitch(
+          chromeos::switches::kNeedArcMigrationPolicyCheck)) {
+    return true;
+  }
+
+  const PrefService* const pref_service =
+      user_manager::UserManager::Get()->GetLocalState();
+  const PrefService::Preference* const pref =
+      pref_service->FindPreference(prefs::kDeviceEcryptfsMigrationStrategy);
+
+  return pref && pref->GetValue() &&
+         pref->GetValue()->GetInt() ==
+             enterprise_management::DeviceEcryptfsMigrationStrategyProto::
+                 ALLOW_MIGRATION;
+}
+
 }  // namespace
 
 bool IsArcAllowedForProfile(const Profile* profile) {
@@ -143,6 +183,22 @@ bool IsArcAllowedForProfile(const Profile* profile) {
     return false;
   }
 
+  // If migration policy check is needed (specified by commandline flag), check
+  // the policy, which should be already available here. If policy says
+  // migration is not allowed, do not run ARC, regardless whether file system
+  // migration is actually needed. For example, even if file system is still
+  // ecryptfs and ARC version is M, or file system is already migrated into ext4
+  // crypt and ARC version is N or later, if policy says migration is not
+  // allowed, ARC will never run. Practically, in the former example case,
+  // --need-arc-migration-policy-check is not set, so this check passes and user
+  // can use ARC. In latter case, policy should say migration is allowed, so
+  // also user can use ARC then.
+  // TODO(igorcov): Remove this after migration. crbug.com/725493
+  if (!IsArcMigrationAllowed()) {
+    VLOG(1) << "ARC migration is not allowed by the policy.";

[bartfab (slow), 2017/06/13 09:56:01]

Nit: s/the //

[igorcov, 2017/06/16 11:13:04]

Done.

+    return false;
+  }
+
   // Do not run ARC instance when supervised user is being created.
   // Otherwise noisy notification may be displayed.
   chromeos::UserFlow* user_flow =
@@ -284,4 +340,14 @@ void UpdateArcFileSystemCompatibilityPrefIfNeeded(
       base::Bind(&StoreCompatibilityCheckResult, account_id, callback));
 }
 
+bool IsArcMigrationAllowed() {
+  if (!g_is_arc_migration_allowed.has_value())
+    g_is_arc_migration_allowed = IsArcMigrationAllowedInternal();
+  return g_is_arc_migration_allowed.value();
+}
+
+void ResetArcMigrationAllowedForTesting() {
+  g_is_arc_migration_allowed.reset();
+}
+
 }  // namespace arc