Display and revoke active sessions

23 files changed, 642 insertions, 47 deletions

diff --git a/Gemfile b/Gemfile
index caeaae96164..a68b044b39e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -184,6 +184,9 @@ gem 're2', '~> 1.1.1'
 
 gem 'version_sorter', '~> 2.1.0'
 
+# User agent parsing
+gem 'device_detector'
+
 # Cache
 gem 'redis-rails', '~> 5.0.2'
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 9b2c47587ee..f11df6a283e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -161,6 +161,7 @@ GEM
       activerecord (>= 3.2.0, < 5.1)
     descendants_tracker (0.0.4)
       thread_safe (~> 0.3, >= 0.3.1)
+    device_detector (1.0.0)
     devise (4.2.0)
       bcrypt (~> 3.0)
       orm_adapter (~> 0.1)
@@ -1026,6 +1027,7 @@ DEPENDENCIES
   database_cleaner (~> 1.5.0)
   deckar01-task_list (= 2.0.0)
   default_value_for (~> 3.0.0)
+  device_detector
   devise (~> 4.2)
   devise-two-factor (~> 3.0.0)
   diffy (~> 3.1.0)
diff --git a/app/assets/stylesheets/framework/common.scss b/app/assets/stylesheets/framework/common.scss
index e058a0b35b7..2faea55a5f5 100644
--- a/app/assets/stylesheets/framework/common.scss
+++ b/app/assets/stylesheets/framework/common.scss
@@ -452,6 +452,7 @@ img.emoji {
 
 /** COMMON CLASSES **/
 .prepend-top-0 { margin-top: 0; }
+.prepend-top-2 { margin-top: 2px; }
 .prepend-top-5 { margin-top: 5px; }
 .prepend-top-8 { margin-top: $grid-size; }
 .prepend-top-10 { margin-top: 10px; }
diff --git a/app/assets/stylesheets/framework/images.scss b/app/assets/stylesheets/framework/images.scss
index 62a0fba3da3..ab3cceceae9 100644
--- a/app/assets/stylesheets/framework/images.scss
+++ b/app/assets/stylesheets/framework/images.scss
@@ -39,35 +39,10 @@
 svg {
   fill: currentColor;
 
-  &.s8 {
-    @include svg-size(8px);
-  }
-
-  &.s12 {
-    @include svg-size(12px);
-  }
-
-  &.s16 {
-    @include svg-size(16px);
-  }
-
-  &.s18 {
-    @include svg-size(18px);
-  }
-
-  &.s24 {
-    @include svg-size(24px);
-  }
-
-  &.s32 {
-    @include svg-size(32px);
-  }
-
-  &.s48 {
-    @include svg-size(48px);
-  }
-
-  &.s72 {
-    @include svg-size(72px);
+  $svg-sizes: 8 12 16 18 24 32 48 72;
+  @each $svg-size in $svg-sizes {
+    &.s#{$svg-size} {
+      @include svg-size(#{$svg-size}px);
+    }
   }
 }
diff --git a/app/controllers/profiles/active_sessions_controller.rb b/app/controllers/profiles/active_sessions_controller.rb
new file mode 100644
index 00000000000..f0cdc228366
--- /dev/null
+++ b/app/controllers/profiles/active_sessions_controller.rb
@@ -0,0 +1,14 @@
+class Profiles::ActiveSessionsController < Profiles::ApplicationController
+  def index
+    @sessions = ActiveSession.list(current_user)
+  end
+
+  def destroy
+    ActiveSession.destroy(current_user, params[:id])
+
+    respond_to do |format|
+      format.html { redirect_to profile_active_sessions_url, status: 302 }
+      format.js { head :ok }
+    end
+  end
+end
diff --git a/app/helpers/active_sessions_helper.rb b/app/helpers/active_sessions_helper.rb
new file mode 100644
index 00000000000..97b6dac67c5
--- /dev/null
+++ b/app/helpers/active_sessions_helper.rb
@@ -0,0 +1,23 @@
+module ActiveSessionsHelper
+  # Maps a device type as defined in `ActiveSession` to an svg icon name and
+  # outputs the icon html.
+  #
+  # see `DeviceDetector::Device::DEVICE_NAMES` about the available device types
+  def active_session_device_type_icon(active_session)
+    icon_name =
+      case active_session.device_type
+      when 'smartphone', 'feature phone', 'phablet'
+        'mobile'
+      when 'tablet'
+        'tablet'
+      when 'tv', 'smart display', 'camera', 'portable media player', 'console'
+        'media'
+      when 'car browser'
+        'car'
+      else
+        'monitor-o'
+      end
+
+    sprite_icon(icon_name, size: 16, css_class: 'prepend-top-2')
+  end
+end
diff --git a/app/models/active_session.rb b/app/models/active_session.rb
new file mode 100644
index 00000000000..b4a86dbb331
--- /dev/null
+++ b/app/models/active_session.rb
@@ -0,0 +1,110 @@
+class ActiveSession
+  include ActiveModel::Model
+
+  attr_accessor :created_at, :updated_at,
+    :session_id, :ip_address,
+    :browser, :os, :device_name, :device_type
+
+  def current?(session)
+    return false if session_id.nil? || session.id.nil?
+
+    session_id == session.id
+  end
+
+  def human_device_type
+    device_type&.titleize
+  end
+
+  def self.set(user, request)
+    Gitlab::Redis::SharedState.with do |redis|
+      session_id = request.session.id
+      client = DeviceDetector.new(request.user_agent)
+      timestamp = Time.current
+
+      active_user_session = new(
+        ip_address: request.ip,
+        browser: client.name,
+        os: client.os_name,
+        device_name: client.device_name,
+        device_type: client.device_type,
+        created_at: user.current_sign_in_at || timestamp,
+        updated_at: timestamp,
+        session_id: session_id
+      )
+
+      redis.pipelined do
+        redis.setex(
+          key_name(user.id, session_id),
+          Settings.gitlab['session_expire_delay'] * 60,
+          Marshal.dump(active_user_session)
+        )
+
+        redis.sadd(
+          lookup_key_name(user.id),
+          session_id
+        )
+      end
+    end
+  end
+
+  def self.list(user)
+    Gitlab::Redis::SharedState.with do |redis|
+      cleaned_up_lookup_entries(redis, user.id).map do |entry|
+        # rubocop:disable Security/MarshalLoad
+        Marshal.load(entry)
+        # rubocop:enable Security/MarshalLoad
+      end
+    end
+  end
+
+  def self.destroy(user, session_id)
+    Gitlab::Redis::SharedState.with do |redis|
+      redis.srem(lookup_key_name(user.id), session_id)
+
+      deleted_keys = redis.del(key_name(user.id, session_id))
+
+      # only allow deleting the devise session if we could actually find a
+      # related active session. this prevents another user from deleting
+      # someone else's session.
+      if deleted_keys > 0
+        redis.del("#{Gitlab::Redis::SharedState::SESSION_NAMESPACE}:#{session_id}")
+      end
+    end
+  end
+
+  def self.cleanup(user)
+    Gitlab::Redis::SharedState.with do |redis|
+      cleaned_up_lookup_entries(redis, user.id)
+    end
+  end
+
+  def self.key_name(user_id, session_id = '*')
+    "#{Gitlab::Redis::SharedState::USER_SESSIONS_NAMESPACE}:#{user_id}:#{session_id}"
+  end
+
+  def self.lookup_key_name(user_id)
+    "#{Gitlab::Redis::SharedState::USER_SESSIONS_LOOKUP_NAMESPACE}:#{user_id}"
+  end
+
+  def self.cleaned_up_lookup_entries(redis, user_id)
+    lookup_key = lookup_key_name(user_id)
+
+    session_ids = redis.smembers(lookup_key)
+
+    entry_keys = session_ids.map { |session_id| key_name(user_id, session_id) }
+    return [] if entry_keys.empty?
+
+    entries = redis.mget(entry_keys)
+
+    session_ids_and_entries = session_ids.zip(entries)
+
+    # remove expired keys.
+    # only the single key entries are automatically expired by redis, the
+    # lookup entries in the set need to be removed manually.
+    session_ids_and_entries.reject { |_session_id, entry| entry }.each do |session_id, _entry|
+      redis.srem(lookup_key, session_id)
+    end
+
+    session_ids_and_entries.select { |_session_id, entry| entry }.map { |_session_id, entry| entry }
+  end
+end
diff --git a/app/views/layouts/nav/sidebar/_profile.html.haml b/app/views/layouts/nav/sidebar/_profile.html.haml
index c878fcf2808..6cbd163dd41 100644
--- a/app/views/layouts/nav/sidebar/_profile.html.haml
+++ b/app/views/layouts/nav/sidebar/_profile.html.haml
@@ -129,6 +129,17 @@
             = link_to profile_preferences_path do
               %strong.fly-out-top-item-name
                 #{ _('Preferences') }
+      = nav_link(controller: :active_sessions) do
+        = link_to profile_active_sessions_path do
+          .nav-icon-container
+            = sprite_icon('monitor-lines')
+          %span.nav-item-name
+            Active Sessions
+        %ul.sidebar-sub-level-items.is-fly-out-only
+          = nav_link(controller: :active_sessions, html_options: { class: "fly-out-top-item" } ) do
+            = link_to profile_active_sessions_path do
+              %strong.fly-out-top-item-name
+                #{ _('Active Sessions') }
       = nav_link(path: 'profiles#audit_log') do
         = link_to audit_log_profile_path do
           .nav-icon-container
diff --git a/app/views/profiles/active_sessions/_active_session.html.haml b/app/views/profiles/active_sessions/_active_session.html.haml
new file mode 100644
index 00000000000..d40b771f48b
--- /dev/null
+++ b/app/views/profiles/active_sessions/_active_session.html.haml
@@ -0,0 +1,31 @@
+- is_current_session = active_session.current?(session)
+
+%li
+  .pull-left.append-right-10{ data: { toggle: 'tooltip' }, title: active_session.human_device_type }
+    = active_session_device_type_icon(active_session)
+
+  .description.pull-left
+    %div
+      %strong= active_session.ip_address
+    - if is_current_session
+      %div This is your current session
+    - else
+      %div
+        Last accessed on
+        = l(active_session.updated_at, format: :short)
+
+    %div
+      %strong= active_session.browser
+      on
+      %strong= active_session.os
+
+    %div
+      %strong Signed in
+      on
+      = l(active_session.created_at, format: :short)
+
+  - unless is_current_session
+    .pull-right
+      = link_to profile_active_session_path(active_session.session_id), data: { confirm: 'Are you sure? The device will be signed out of GitLab.' }, method: :delete, class: "btn btn-danger prepend-left-10" do
+        %span.sr-only Revoke
+        Revoke
diff --git a/app/views/profiles/active_sessions/index.html.haml b/app/views/profiles/active_sessions/index.html.haml
new file mode 100644
index 00000000000..d0250bb4eab
--- /dev/null
+++ b/app/views/profiles/active_sessions/index.html.haml
@@ -0,0 +1,14 @@
+- page_title 'Active Sessions'
+- @content_class = "limit-container-width" unless fluid_layout
+
+.row.prepend-top-default
+  .col-lg-4.profile-settings-sidebar
+    %h4.prepend-top-0
+      = page_title
+    %p
+      This is a list of devices that have logged into your account. Revoke any sessions that you do not recognize.
+  .col-lg-8
+    .append-bottom-default
+
+      %ul.well-list
+        = render partial: 'profiles/active_sessions/active_session', collection: @sessions
diff --git a/changelogs/unreleased/feature-display-active-sessions.yml b/changelogs/unreleased/feature-display-active-sessions.yml
new file mode 100644
index 00000000000..14cfa66953e
--- /dev/null
+++ b/changelogs/unreleased/feature-display-active-sessions.yml
@@ -0,0 +1,5 @@
+---
+title: Display active sessions and allow the user to revoke any of it
+merge_request: 17867
+author: Alexis Reigel
+type: added
diff --git a/config/initializers/session_store.rb b/config/initializers/session_store.rb
index f2fde1e0048..da24881885e 100644
--- a/config/initializers/session_store.rb
+++ b/config/initializers/session_store.rb
@@ -15,19 +15,15 @@ cookie_key = if Rails.env.development?
                "_gitlab_session"
              end
 
-if Rails.env.test?
-  Gitlab::Application.config.session_store :cookie_store, key: "_gitlab_session"
-else
-  sessions_config = Gitlab::Redis::SharedState.params
-  sessions_config[:namespace] = Gitlab::Redis::SharedState::SESSION_NAMESPACE
+sessions_config = Gitlab::Redis::SharedState.params
+sessions_config[:namespace] = Gitlab::Redis::SharedState::SESSION_NAMESPACE
 
-  Gitlab::Application.config.session_store(
-    :redis_store, # Using the cookie_store would enable session replay attacks.
-    servers: sessions_config,
-    key: cookie_key,
-    secure: Gitlab.config.gitlab.https,
-    httponly: true,
-    expires_in: Settings.gitlab['session_expire_delay'] * 60,
-    path: Rails.application.config.relative_url_root.nil? ? '/' : Gitlab::Application.config.relative_url_root
-  )
-end
+Gitlab::Application.config.session_store(
+  :redis_store, # Using the cookie_store would enable session replay attacks.
+  servers: sessions_config,
+  key: cookie_key,
+  secure: Gitlab.config.gitlab.https,
+  httponly: true,
+  expires_in: Settings.gitlab['session_expire_delay'] * 60,
+  path: Rails.application.config.relative_url_root.nil? ? '/' : Gitlab::Application.config.relative_url_root
+)
diff --git a/config/initializers/warden.rb b/config/initializers/warden.rb
index ee034d21eae..bf079f8e1a7 100644
--- a/config/initializers/warden.rb
+++ b/config/initializers/warden.rb
@@ -6,4 +6,16 @@ Rails.application.configure do |config|
   Warden::Manager.before_failure do |env, opts|
     Gitlab::Auth::BlockedUserTracker.log_if_user_blocked(env)
   end
+
+  Warden::Manager.after_authentication do |user, auth, opts|
+    ActiveSession.cleanup(user)
+  end
+
+  Warden::Manager.after_set_user only: :fetch do |user, auth, opts|
+    ActiveSession.set(user, auth.request)
+  end
+
+  Warden::Manager.before_logout do |user, auth, opts|
+    ActiveSession.destroy(user || auth.user, auth.request.session.id)
+  end
 end
diff --git a/config/routes/profile.rb b/config/routes/profile.rb
index bcfc17a5f66..a9ba5ac2c0b 100644
--- a/config/routes/profile.rb
+++ b/config/routes/profile.rb
@@ -30,6 +30,7 @@ resource :profile, only: [:show, :update] do
         put :revoke
       end
     end
+    resources :active_sessions, only: [:index, :destroy]
     resources :emails, only: [:index, :create, :destroy] do
       member do
         put :resend_confirmation_instructions
diff --git a/doc/development/fe_guide/icons.md b/doc/development/fe_guide/icons.md
index b288ee95722..b469a9c6aef 100644
--- a/doc/development/fe_guide/icons.md
+++ b/doc/development/fe_guide/icons.md
@@ -49,7 +49,7 @@ Please use the following function inside JS to render an icon :
 
 All Icons and Illustrations are managed in the [gitlab-svgs](https://gitlab.com/gitlab-org/gitlab-svgs) repository which is added as a dev-dependency.
 
-To upgrade to a new SVG Sprite version run `yarn upgrade @gitlab-org/gitlab-svgs` and then run `yarn run svg`. This task will copy the svg sprite and all illustrations in the correct folders. The updated files should be tracked in Git as those are referenced.
+To upgrade to a new SVG Sprite version run `yarn upgrade @gitlab-org/gitlab-svgs`.
 
 # SVG Illustrations
 
diff --git a/doc/user/profile/active_sessions.md b/doc/user/profile/active_sessions.md
new file mode 100644
index 00000000000..5119c0e30d0
--- /dev/null
+++ b/doc/user/profile/active_sessions.md
@@ -0,0 +1,20 @@
+# Active Sessions
+
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17867)
+>   in GitLab 10.8.
+
+GitLab lists all devices that have logged into your account. This allows you to
+review the sessions and revoke any of it that you don't recognize.
+
+## Listing all active sessions
+
+1. On the upper right corner, click on your avatar and go to your **Settings**.
+1. Navigate to the **Active Sessions** tab.
+
+![Active sessions list](img/active_sessions_list.png)
+
+## Revoking a session
+
+1. Navigate to your [profile's](#profile-settings) **Settings > Active Sessions**.
+1. Click on **Revoke** besides a session. The current session cannot be
+   revoked, as this would sign you out of GitLab.
diff --git a/doc/user/profile/img/active_sessions_list.png b/doc/user/profile/img/active_sessions_list.png
new file mode 100644
index 00000000000..76a52220bcd
--- /dev/null
+++ b/doc/user/profile/img/active_sessions_list.png
diff --git a/doc/user/profile/index.md b/doc/user/profile/index.md
index ab16f8d14c1..91cdef8d1dd 100644
--- a/doc/user/profile/index.md
+++ b/doc/user/profile/index.md
@@ -39,6 +39,7 @@ From there, you can:
 - Manage [SSH keys](../../ssh/README.md#ssh) to access your account via SSH
 - Manage your [preferences](preferences.md#syntax-highlighting-theme)
 to customize your own GitLab experience
+- [View your active sessions](active_sessions.md) and revoke any of them if necessary
 - Access your audit log, a security log of important events involving your account
 
 ## Changing your username
diff --git a/lib/gitlab/redis/shared_state.rb b/lib/gitlab/redis/shared_state.rb
index 10bec7a90da..e5a0fdae7ef 100644
--- a/lib/gitlab/redis/shared_state.rb
+++ b/lib/gitlab/redis/shared_state.rb
@@ -5,6 +5,8 @@ module Gitlab
   module Redis
     class SharedState < ::Gitlab::Redis::Wrapper
       SESSION_NAMESPACE = 'session:gitlab'.freeze
+      USER_SESSIONS_NAMESPACE = 'session:user:gitlab'.freeze
+      USER_SESSIONS_LOOKUP_NAMESPACE = 'session:lookup:user:gitlab'.freeze
       DEFAULT_REDIS_SHARED_STATE_URL = 'redis://localhost:6382'.freeze
       REDIS_SHARED_STATE_CONFIG_ENV_VAR_NAME = 'GITLAB_REDIS_SHARED_STATE_CONFIG_FILE'.freeze
 
diff --git a/spec/controllers/projects/clusters/gcp_controller_spec.rb b/spec/controllers/projects/clusters/gcp_controller_spec.rb
index e14ba29fa70..715bb9f5e52 100644
--- a/spec/controllers/projects/clusters/gcp_controller_spec.rb
+++ b/spec/controllers/projects/clusters/gcp_controller_spec.rb
@@ -142,7 +142,7 @@ describe Projects::Clusters::GcpController do
 
         context 'when google project billing is enabled' do
           before do
-            redis_double = double
+            redis_double = double.as_null_object
             allow(Gitlab::Redis::SharedState).to receive(:with).and_yield(redis_double)
             allow(redis_double).to receive(:get).with(CheckGcpProjectBillingWorker.redis_shared_state_key_for('token')).and_return('true')
           end
diff --git a/spec/features/profiles/active_sessions_spec.rb b/spec/features/profiles/active_sessions_spec.rb
new file mode 100644
index 00000000000..4045cfd21c4
--- /dev/null
+++ b/spec/features/profiles/active_sessions_spec.rb
@@ -0,0 +1,89 @@
+require 'rails_helper'
+
+feature 'Profile > Active Sessions', :clean_gitlab_redis_shared_state do
+  let(:user) do
+    create(:user).tap do |user|
+      user.current_sign_in_at = Time.current
+    end
+  end
+
+  around do |example|
+    Timecop.freeze(Time.zone.parse('2018-03-12 09:06')) do
+      example.run
+    end
+  end
+
+  scenario 'User sees their active sessions' do
+    Capybara::Session.new(:session1)
+    Capybara::Session.new(:session2)
+
+    # note: headers can only be set on the non-js (aka. rack-test) driver
+    using_session :session1 do
+      Capybara.page.driver.header(
+        'User-Agent',
+        'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:58.0) Gecko/20100101 Firefox/58.0'
+      )
+
+      gitlab_sign_in(user)
+    end
+
+    # set an additional session on another device
+    using_session :session2 do
+      Capybara.page.driver.header(
+        'User-Agent',
+        'Mozilla/5.0 (iPhone; CPU iPhone OS 8_1_3 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Mobile/12B466 [FBDV/iPhone7,2]'
+      )
+
+      gitlab_sign_in(user)
+    end
+
+    using_session :session1 do
+      visit profile_active_sessions_path
+
+      expect(page).to have_content(
+        '127.0.0.1 ' \
+        'This is your current session ' \
+        'Firefox on Ubuntu ' \
+        'Signed in on 12 Mar 09:06'
+      )
+
+      expect(page).to have_selector '[title="Desktop"]', count: 1
+
+      expect(page).to have_content(
+        '127.0.0.1 ' \
+        'Last accessed on 12 Mar 09:06 ' \
+        'Mobile Safari on iOS ' \
+        'Signed in on 12 Mar 09:06'
+      )
+
+      expect(page).to have_selector '[title="Smartphone"]', count: 1
+    end
+  end
+
+  scenario 'User can revoke a session', :js, :redis_session_store do
+    Capybara::Session.new(:session1)
+    Capybara::Session.new(:session2)
+
+    # set an additional session in another browser
+    using_session :session2 do
+      gitlab_sign_in(user)
+    end
+
+    using_session :session1 do
+      gitlab_sign_in(user)
+      visit profile_active_sessions_path
+
+      expect(page).to have_link('Revoke', count: 1)
+
+      accept_confirm { click_on 'Revoke' }
+
+      expect(page).not_to have_link('Revoke')
+    end
+
+    using_session :session2 do
+      visit profile_active_sessions_path
+
+      expect(page).to have_content('You need to sign in or sign up before continuing.')
+    end
+  end
+end
diff --git a/spec/features/users/active_sessions_spec.rb b/spec/features/users/active_sessions_spec.rb
new file mode 100644
index 00000000000..631d7e3bced
--- /dev/null
+++ b/spec/features/users/active_sessions_spec.rb
@@ -0,0 +1,69 @@
+require 'spec_helper'
+
+feature 'Active user sessions', :clean_gitlab_redis_shared_state do
+  scenario 'Successful login adds a new active user login' do
+    now = Time.zone.parse('2018-03-12 09:06')
+    Timecop.freeze(now) do
+      user = create(:user)
+      gitlab_sign_in(user)
+      expect(current_path).to eq root_path
+
+      sessions = ActiveSession.list(user)
+      expect(sessions.count).to eq 1
+
+      # refresh the current page updates the updated_at
+      Timecop.freeze(now + 1.minute) do
+        visit current_path
+
+        sessions = ActiveSession.list(user)
+        expect(sessions.first).to have_attributes(
+          created_at: Time.zone.parse('2018-03-12 09:06'),
+          updated_at: Time.zone.parse('2018-03-12 09:07')
+        )
+      end
+    end
+  end
+
+  scenario 'Successful login cleans up obsolete entries' do
+    user = create(:user)
+
+    Gitlab::Redis::SharedState.with do |redis|
+      redis.sadd("session:lookup:user:gitlab:#{user.id}", '59822c7d9fcdfa03725eff41782ad97d')
+    end
+
+    gitlab_sign_in(user)
+
+    Gitlab::Redis::SharedState.with do |redis|
+      expect(redis.smembers("session:lookup:user:gitlab:#{user.id}")).not_to include '59822c7d9fcdfa03725eff41782ad97d'
+    end
+  end
+
+  scenario 'Sessionless login does not clean up obsolete entries' do
+    user = create(:user)
+    personal_access_token = create(:personal_access_token, user: user)
+
+    Gitlab::Redis::SharedState.with do |redis|
+      redis.sadd("session:lookup:user:gitlab:#{user.id}", '59822c7d9fcdfa03725eff41782ad97d')
+    end
+
+    visit user_path(user, :atom, private_token: personal_access_token.token)
+    expect(page.status_code).to eq 200
+
+    Gitlab::Redis::SharedState.with do |redis|
+      expect(redis.smembers("session:lookup:user:gitlab:#{user.id}")).to include '59822c7d9fcdfa03725eff41782ad97d'
+    end
+  end
+
+  scenario 'Logout deletes the active user login' do
+    user = create(:user)
+    gitlab_sign_in(user)
+    expect(current_path).to eq root_path
+
+    expect(ActiveSession.list(user).count).to eq 1
+
+    gitlab_sign_out
+    expect(current_path).to eq new_user_session_path
+
+    expect(ActiveSession.list(user)).to be_empty
+  end
+end
diff --git a/spec/models/active_session_spec.rb b/spec/models/active_session_spec.rb
new file mode 100644
index 00000000000..129b2f92683
--- /dev/null
+++ b/spec/models/active_session_spec.rb
@@ -0,0 +1,216 @@
+require 'rails_helper'
+
+RSpec.describe ActiveSession, :clean_gitlab_redis_shared_state do
+  let(:user) do
+    create(:user).tap do |user|
+      user.current_sign_in_at = Time.current
+    end
+  end
+
+  let(:session) { double(:session, id: '6919a6f1bb119dd7396fadc38fd18d0d') }
+
+  let(:request) do
+    double(:request, {
+      user_agent: 'Mozilla/5.0 (iPhone; CPU iPhone OS 8_1_3 like Mac OS X) AppleWebKit/600.1.4 ' \
+        '(KHTML, like Gecko) Mobile/12B466 [FBDV/iPhone7,2]',
+      ip: '127.0.0.1',
+      session: session
+    })
+  end
+
+  describe '#current?' do
+    it 'returns true if the active session matches the current session' do
+      active_session = ActiveSession.new(session_id: '6919a6f1bb119dd7396fadc38fd18d0d')
+
+      expect(active_session.current?(session)).to be true
+    end
+
+    it 'returns false if the active session does not match the current session' do
+      active_session = ActiveSession.new(session_id: '59822c7d9fcdfa03725eff41782ad97d')
+
+      expect(active_session.current?(session)).to be false
+    end
+
+    it 'returns false if the session id is nil' do
+      active_session = ActiveSession.new(session_id: nil)
+      session = double(:session, id: nil)
+
+      expect(active_session.current?(session)).to be false
+    end
+  end
+
+  describe '.list' do
+    it 'returns all sessions by user' do
+      Gitlab::Redis::SharedState.with do |redis|
+        redis.set("session:user:gitlab:#{user.id}:6919a6f1bb119dd7396fadc38fd18d0d", Marshal.dump({ session_id: 'a' }))
+        redis.set("session:user:gitlab:#{user.id}:59822c7d9fcdfa03725eff41782ad97d", Marshal.dump({ session_id: 'b' }))
+        redis.set("session:user:gitlab:9999:5c8611e4f9c69645ad1a1492f4131358", '')
+
+        redis.sadd(
+          "session:lookup:user:gitlab:#{user.id}",
+          %w[
+            6919a6f1bb119dd7396fadc38fd18d0d
+            59822c7d9fcdfa03725eff41782ad97d
+          ]
+        )
+      end
+
+      expect(ActiveSession.list(user)).to match_array [{ session_id: 'a' }, { session_id: 'b' }]
+    end
+
+    it 'does not return obsolete entries and cleans them up' do
+      Gitlab::Redis::SharedState.with do |redis|
+        redis.set("session:user:gitlab:#{user.id}:6919a6f1bb119dd7396fadc38fd18d0d", Marshal.dump({ session_id: 'a' }))
+
+        redis.sadd(
+          "session:lookup:user:gitlab:#{user.id}",
+          %w[
+            6919a6f1bb119dd7396fadc38fd18d0d
+            59822c7d9fcdfa03725eff41782ad97d
+          ]
+        )
+      end
+
+      expect(ActiveSession.list(user)).to eq [{ session_id: 'a' }]
+
+      Gitlab::Redis::SharedState.with do |redis|
+        expect(redis.sscan_each("session:lookup:user:gitlab:#{user.id}").to_a).to eq ['6919a6f1bb119dd7396fadc38fd18d0d']
+      end
+    end
+
+    it 'returns an empty array if the use does not have any active session' do
+      expect(ActiveSession.list(user)).to eq []
+    end
+  end
+
+  describe '.set' do
+    it 'sets a new redis entry for the user session and a lookup entry' do
+      ActiveSession.set(user, request)
+
+      Gitlab::Redis::SharedState.with do |redis|
+        expect(redis.scan_each.to_a).to match_array [
+          "session:user:gitlab:#{user.id}:6919a6f1bb119dd7396fadc38fd18d0d",
+          "session:lookup:user:gitlab:#{user.id}"
+        ]
+      end
+    end
+
+    it 'adds timestamps and information from the request' do
+      Timecop.freeze(Time.zone.parse('2018-03-12 09:06')) do
+        ActiveSession.set(user, request)
+
+        session = ActiveSession.list(user)
+
+        expect(session.count).to eq 1
+        expect(session.first).to have_attributes(
+          ip_address: '127.0.0.1',
+          browser: 'Mobile Safari',
+          os: 'iOS',
+          device_name: 'iPhone 6',
+          device_type: 'smartphone',
+          created_at: Time.zone.parse('2018-03-12 09:06'),
+          updated_at: Time.zone.parse('2018-03-12 09:06'),
+          session_id: '6919a6f1bb119dd7396fadc38fd18d0d'
+        )
+      end
+    end
+
+    it 'keeps the created_at from the login on consecutive requests' do
+      now = Time.zone.parse('2018-03-12 09:06')
+
+      Timecop.freeze(now) do
+        ActiveSession.set(user, request)
+
+        Timecop.freeze(now + 1.minute) do
+          ActiveSession.set(user, request)
+
+          session = ActiveSession.list(user)
+
+          expect(session.first).to have_attributes(
+            created_at: Time.zone.parse('2018-03-12 09:06'),
+            updated_at: Time.zone.parse('2018-03-12 09:07')
+          )
+        end
+      end
+    end
+  end
+
+  describe '.destroy' do
+    it 'removes the entry associated with the currently killed user session' do
+      Gitlab::Redis::SharedState.with do |redis|
+        redis.set("session:user:gitlab:#{user.id}:6919a6f1bb119dd7396fadc38fd18d0d", '')
+        redis.set("session:user:gitlab:#{user.id}:59822c7d9fcdfa03725eff41782ad97d", '')
+        redis.set("session:user:gitlab:9999:5c8611e4f9c69645ad1a1492f4131358", '')
+      end
+
+      ActiveSession.destroy(user, request.session.id)
+
+      Gitlab::Redis::SharedState.with do |redis|
+        expect(redis.scan_each(match: "session:user:gitlab:*")).to match_array [
+          "session:user:gitlab:#{user.id}:59822c7d9fcdfa03725eff41782ad97d",
+          "session:user:gitlab:9999:5c8611e4f9c69645ad1a1492f4131358"
+        ]
+      end
+    end
+
+    it 'removes the lookup entry' do
+      Gitlab::Redis::SharedState.with do |redis|
+        redis.set("session:user:gitlab:#{user.id}:6919a6f1bb119dd7396fadc38fd18d0d", '')
+        redis.sadd("session:lookup:user:gitlab:#{user.id}", '6919a6f1bb119dd7396fadc38fd18d0d')
+      end
+
+      ActiveSession.destroy(user, request.session.id)
+
+      Gitlab::Redis::SharedState.with do |redis|
+        expect(redis.scan_each(match: "session:lookup:user:gitlab:#{user.id}").to_a).to be_empty
+      end
+    end
+
+    it 'removes the devise session' do
+      Gitlab::Redis::SharedState.with do |redis|
+        redis.set("session:user:gitlab:#{user.id}:6919a6f1bb119dd7396fadc38fd18d0d", '')
+        redis.set("session:gitlab:6919a6f1bb119dd7396fadc38fd18d0d", '')
+      end
+
+      ActiveSession.destroy(user, request.session.id)
+
+      Gitlab::Redis::SharedState.with do |redis|
+        expect(redis.scan_each(match: "session:gitlab:*").to_a).to be_empty
+      end
+    end
+
+    it 'does not remove the devise session if the active session could not be found' do
+      Gitlab::Redis::SharedState.with do |redis|
+        redis.set("session:gitlab:6919a6f1bb119dd7396fadc38fd18d0d", '')
+      end
+
+      other_user = create(:user)
+
+      ActiveSession.destroy(other_user, request.session.id)
+
+      Gitlab::Redis::SharedState.with do |redis|
+        expect(redis.scan_each(match: "session:gitlab:*").to_a).not_to be_empty
+      end
+    end
+  end
+
+  describe '.cleanup' do
+    it 'removes obsolete lookup entries' do
+      Gitlab::Redis::SharedState.with do |redis|
+        redis.set("session:user:gitlab:#{user.id}:6919a6f1bb119dd7396fadc38fd18d0d", '')
+        redis.sadd("session:lookup:user:gitlab:#{user.id}", '6919a6f1bb119dd7396fadc38fd18d0d')
+        redis.sadd("session:lookup:user:gitlab:#{user.id}", '59822c7d9fcdfa03725eff41782ad97d')
+      end
+
+      ActiveSession.cleanup(user)
+
+      Gitlab::Redis::SharedState.with do |redis|
+        expect(redis.smembers("session:lookup:user:gitlab:#{user.id}")).to eq ['6919a6f1bb119dd7396fadc38fd18d0d']
+      end
+    end
+
+    it 'does not bail if there are no lookup entries' do
+      ActiveSession.cleanup(user)
+    end
+  end
+end