Add policy that forces SAML users to log in online periodically

chrome/browser/chromeos/login/saml/saml_offline_signin_limiter.cc

+// Copyright 2014 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/browser/chromeos/login/saml/saml_offline_signin_limiter.h"
+
+#include <string>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/prefs/pref_service.h"
+#include "base/time/clock.h"
+#include "base/time/time.h"
+#include "chrome/browser/chromeos/login/user_manager.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/common/pref_names.h"
+#include "components/user_prefs/pref_registry_syncable.h"
+
+namespace chromeos {
+
+namespace {
+
+const int kDefaultSAMLOfflineSigninTimeLimit = 14 * 24 * 60 * 60;  // 14 days.
+
+}  // namespace
+
+// static
+void SAMLOfflineSigninLimiter::RegisterProfilePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterIntegerPref(
+      prefs::kSAMLOfflineSigninTimeLimit,
+      kDefaultSAMLOfflineSigninTimeLimit,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+  registry->RegisterInt64Pref(
+      prefs::kSAMLLastGAIASignInTime,
+      0,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+}
+
+void SAMLOfflineSigninLimiter::SignedIn(UserContext::AuthFlow auth_flow) {
+  PrefService* prefs = profile_->GetPrefs();
+  const User* user = UserManager::Get()->GetUserByProfile(profile_);
+  if (!user) {
+    NOTREACHED();
+    return;
+  }
+  const std::string& user_id = user->email();
+
+  if (auth_flow == UserContext::AUTH_FLOW_GAIA_WITHOUT_SAML) {
+    // The user went through online authentication and GAIA did not redirect to
+    // a SAML IdP. No limit applies in this case. Clear the time of last login
+    // with SAML and the flag enforcing online login, then return.
+    prefs->ClearPref(prefs::kSAMLLastGAIASignInTime);
+    UserManager::Get()->SaveForceOnlineSignin(user_id, false);
+    return;
+  }
+
+  if (auth_flow == UserContext::AUTH_FLOW_GAIA_WITH_SAML) {
+    // The user went through online authentication and GAIA did redirect to a
+    // SAML IdP. Update the time of last login with SAML and clear the flag
+    // enforcing online login. The flag will be set again when the limit
+    // expires. If the limit already expired (e.g. because it was set to zero),
+    // the flag will be set again immediately.
+    UserManager::Get()->SaveForceOnlineSignin(user_id, false);
+    prefs->SetInt64(prefs::kSAMLLastGAIASignInTime,
+                    clock_->Now().ToInternalValue());
+  }
+
+  // Start listening for pref changes.
+  pref_change_registrar_.Init(prefs);
+  pref_change_registrar_.Add(prefs::kSAMLOfflineSigninTimeLimit,
+                             base::Bind(&SAMLOfflineSigninLimiter::UpdateLimit,
+                                        base::Unretained(this)));
+
+  // Arm the |offline_signin_limit_timer_| if a limit is in force.
+  UpdateLimit();
+}
+
+void SAMLOfflineSigninLimiter::Shutdown() {
+  pref_change_registrar_.RemoveAll();
+  offline_signin_limit_timer_.reset();
+}
+
+SAMLOfflineSigninLimiter::SAMLOfflineSigninLimiter(Profile* profile,
+                                                   base::Clock* clock)
+    : profile_(profile),
+      clock_(clock ? clock : &default_clock_) {
+}
+
+SAMLOfflineSigninLimiter::~SAMLOfflineSigninLimiter() {
+}
+
+void SAMLOfflineSigninLimiter::UpdateLimit() {
+  // Stop the |offline_signin_limit_timer_|.
+  offline_signin_limit_timer_.reset();
+
+  PrefService* prefs = pref_change_registrar_.prefs();
+  const base::TimeDelta offline_signin_time_limit =
+      base::TimeDelta::FromSeconds(
+          prefs->GetInteger(prefs::kSAMLOfflineSigninTimeLimit));
+  base::Time last_gaia_signin_time = base::Time::FromInternalValue(
+      prefs->GetInt64(prefs::kSAMLLastGAIASignInTime));
+  if (offline_signin_time_limit < base::TimeDelta() ||
+      last_gaia_signin_time.is_null()) {
+    // If no limit is in force, return.
+    return;
+  }
+
+  const base::Time now = clock_->Now();
+  if (last_gaia_signin_time > now) {
+    // If the time of last login with SAML lies in the future, set it to the
+    // current time.
+    NOTREACHED();
+    last_gaia_signin_time = now;
+    prefs->SetInt64(prefs::kSAMLLastGAIASignInTime, now.ToInternalValue());
+  }
+
+  const base::TimeDelta time_since_last_gaia_signin =
+      now - last_gaia_signin_time;
+  if (time_since_last_gaia_signin >= offline_signin_time_limit) {
+    // If the limit already expired, set the flag enforcing online login
+    // immediately and return.
+    ForceOnlineLogin();
+    return;
+  }
+
+  // Arm |offline_signin_limit_timer_| so that it sets the flag enforcing online
+  // login when the limit expires.
+  offline_signin_limit_timer_.reset(
+      new base::OneShotTimer<SAMLOfflineSigninLimiter>);
+  offline_signin_limit_timer_->Start(
+      FROM_HERE,
+      offline_signin_time_limit - time_since_last_gaia_signin,
+      this,
+      &SAMLOfflineSigninLimiter::ForceOnlineLogin);
+}
+
+void SAMLOfflineSigninLimiter::ForceOnlineLogin() {
+  User* user = UserManager::Get()->GetUserByProfile(profile_);
+  if (!user) {
+    NOTREACHED();
+    return;
+  }
+
+  UserManager::Get()->SaveForceOnlineSignin(user->email(), true);
+  offline_signin_limit_timer_.reset();
+}
+
+}  // namespace chromeos