Implement OpenID Connect identity provider

23 files changed, 388 insertions, 9 deletions

diff --git a/Gemfile b/Gemfile
index 4ac5a0ccfc1..b66cd38b4dc 100644
--- a/Gemfile
+++ b/Gemfile
@@ -20,6 +20,7 @@ gem 'rugged', '~> 0.24.0'
 # Authentication libraries
 gem 'devise',                 '~> 4.2'
 gem 'doorkeeper',             '~> 4.2.0'
+gem 'doorkeeper-openid_connect', '~> 1.1.0'
 gem 'omniauth',               '~> 1.4.2'
 gem 'omniauth-auth0',         '~> 1.4.1'
 gem 'omniauth-azure-oauth2',  '~> 0.0.6'
diff --git a/Gemfile.lock b/Gemfile.lock
index d4131a3dede..62388628eaa 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -78,6 +78,7 @@ GEM
     better_errors (1.0.1)
       coderay (>= 1.0.0)
       erubis (>= 2.6.6)
+    bindata (2.3.5)
     binding_of_caller (0.7.2)
       debug_inspector (>= 0.0.1)
     bootstrap-sass (3.3.6)
@@ -167,6 +168,9 @@ GEM
       unf (>= 0.0.5, < 1.0.0)
     doorkeeper (4.2.0)
       railties (>= 4.2)
+    doorkeeper-openid_connect (1.1.2)
+      doorkeeper (~> 4.0)
+      json-jwt (~> 1.6)
     dropzonejs-rails (0.7.2)
       rails (> 3.1)
     email_reply_trimmer (0.1.6)
@@ -376,6 +380,12 @@ GEM
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
     json (1.8.6)
+    json-jwt (1.7.1)
+      activesupport
+      bindata
+      multi_json (>= 1.3)
+      securecompare
+      url_safe_base64
     json-schema (2.6.2)
       addressable (~> 2.3.8)
     jwt (1.5.6)
@@ -684,6 +694,7 @@ GEM
     scss_lint (0.47.1)
       rake (>= 0.9, < 11)
       sass (~> 3.4.15)
+    securecompare (1.0.0)
     seed-fu (2.3.6)
       activerecord (>= 3.1)
       activesupport (>= 3.1)
@@ -789,6 +800,7 @@ GEM
       get_process_mem (~> 0)
       unicorn (>= 4, < 6)
     uniform_notifier (1.10.0)
+    url_safe_base64 (0.2.2)
     validates_hostname (1.0.6)
       activerecord (>= 3.0)
       activesupport (>= 3.0)
@@ -866,6 +878,7 @@ DEPENDENCIES
   devise-two-factor (~> 3.0.0)
   diffy (~> 3.1.0)
   doorkeeper (~> 4.2.0)
+  doorkeeper-openid_connect (~> 1.1.0)
   dropzonejs-rails (~> 0.7.1)
   email_reply_trimmer (~> 0.1)
   email_spec (~> 1.6.0)
diff --git a/app/models/oauth_access_grant.rb b/app/models/oauth_access_grant.rb
new file mode 100644
index 00000000000..3a997406565
--- /dev/null
+++ b/app/models/oauth_access_grant.rb
@@ -0,0 +1,4 @@
+class OauthAccessGrant < Doorkeeper::AccessGrant
+  belongs_to :resource_owner, class_name: 'User'
+  belongs_to :application, class_name: 'Doorkeeper::Application'
+end
diff --git a/app/models/oauth_access_token.rb b/app/models/oauth_access_token.rb
index 116fb71ac08..b85f5dbaf2e 100644
--- a/app/models/oauth_access_token.rb
+++ b/app/models/oauth_access_token.rb
@@ -1,4 +1,4 @@
-class OauthAccessToken < ActiveRecord::Base
+class OauthAccessToken < Doorkeeper::AccessToken
   belongs_to :resource_owner, class_name: 'User'
   belongs_to :application, class_name: 'Doorkeeper::Application'
 end
diff --git a/app/views/doorkeeper/authorizations/new.html.haml b/app/views/doorkeeper/authorizations/new.html.haml
index a196561f381..82aa51f9778 100644
--- a/app/views/doorkeeper/authorizations/new.html.haml
+++ b/app/views/doorkeeper/authorizations/new.html.haml
@@ -27,6 +27,7 @@
       = hidden_field_tag :state, @pre_auth.state
       = hidden_field_tag :response_type, @pre_auth.response_type
       = hidden_field_tag :scope, @pre_auth.scope
+      = hidden_field_tag :nonce, @pre_auth.nonce
       = submit_tag "Authorize", class: "btn btn-success wide pull-left"
     = form_tag oauth_authorization_path, method: :delete do
       = hidden_field_tag :client_id, @pre_auth.client.uid
@@ -34,4 +35,5 @@
       = hidden_field_tag :state, @pre_auth.state
       = hidden_field_tag :response_type, @pre_auth.response_type
       = hidden_field_tag :scope, @pre_auth.scope
+      = hidden_field_tag :nonce, @pre_auth.nonce
       = submit_tag "Deny", class: "btn btn-danger prepend-left-10"
diff --git a/changelogs/unreleased/feature-openid-connect.yml b/changelogs/unreleased/feature-openid-connect.yml
new file mode 100644
index 00000000000..e84eb7aff86
--- /dev/null
+++ b/changelogs/unreleased/feature-openid-connect.yml
@@ -0,0 +1,4 @@
+---
+title: Implement OpenID Connect identity provider
+merge_request: 8018
+author: Markus Koller
diff --git a/config/initializers/doorkeeper.rb b/config/initializers/doorkeeper.rb
index 88cd0f5f652..52551a5d5eb 100644
--- a/config/initializers/doorkeeper.rb
+++ b/config/initializers/doorkeeper.rb
@@ -8,7 +8,12 @@ Doorkeeper.configure do
     # Put your resource owner authentication logic here.
     # Ensure user is redirected to redirect_uri after login
     session[:user_return_to] = request.fullpath
-    current_user || redirect_to(new_user_session_url)
+    if current_user
+      current_user
+    else
+      redirect_to(new_user_session_url)
+      nil
+    end
   end
 
   resource_owner_from_credentials do |routes|
diff --git a/config/initializers/doorkeeper_openid_connect.rb b/config/initializers/doorkeeper_openid_connect.rb
new file mode 100644
index 00000000000..700ca25b884
--- /dev/null
+++ b/config/initializers/doorkeeper_openid_connect.rb
@@ -0,0 +1,36 @@
+Doorkeeper::OpenidConnect.configure do
+  issuer Gitlab.config.gitlab.url
+
+  jws_private_key Rails.application.secrets.jws_private_key
+
+  resource_owner_from_access_token do |access_token|
+    User.active.find_by(id: access_token.resource_owner_id)
+  end
+
+  auth_time_from_resource_owner do |user|
+    user.current_sign_in_at
+  end
+
+  reauthenticate_resource_owner do |user, return_to|
+    store_location_for user, return_to
+    sign_out user
+    redirect_to new_user_session_url
+  end
+
+  subject do |user|
+    # hash the user's ID with the Rails secret_key_base to avoid revealing it
+    Digest::SHA256.hexdigest "#{user.id}-#{Rails.application.secrets.secret_key_base}"
+  end
+
+  claims do
+    with_options scope: :openid do |o|
+      o.claim(:name)           { |user| user.name }
+      o.claim(:nickname)       { |user| user.username }
+      o.claim(:email)          { |user| user.public_email  }
+      o.claim(:email_verified) { |user| true if user.public_email? }
+      o.claim(:website)        { |user| user.full_website_url if user.website_url? }
+      o.claim(:profile)        { |user| Rails.application.routes.url_helpers.user_url user }
+      o.claim(:picture)        { |user| user.avatar_url }
+    end
+  end
+end
diff --git a/config/initializers/secret_token.rb b/config/initializers/secret_token.rb
index 291fa6c0abc..f9c1d2165d3 100644
--- a/config/initializers/secret_token.rb
+++ b/config/initializers/secret_token.rb
@@ -24,7 +24,8 @@ def create_tokens
   defaults = {
     secret_key_base: file_secret_key || generate_new_secure_token,
     otp_key_base: env_secret_key || file_secret_key || generate_new_secure_token,
-    db_key_base: generate_new_secure_token
+    db_key_base: generate_new_secure_token,
+    jws_private_key: generate_new_rsa_private_key
   }
 
   missing_secrets = set_missing_keys(defaults)
@@ -41,6 +42,10 @@ def generate_new_secure_token
   SecureRandom.hex(64)
 end
 
+def generate_new_rsa_private_key
+  OpenSSL::PKey::RSA.new(2048).to_pem
+end
+
 def warn_missing_secret(secret)
   warn "Missing Rails.application.secrets.#{secret} for #{Rails.env} environment. The secret will be generated and stored in config/secrets.yml."
 end
diff --git a/config/locales/doorkeeper.en.yml b/config/locales/doorkeeper.en.yml
index 1d728282d90..14d49885fb3 100644
--- a/config/locales/doorkeeper.en.yml
+++ b/config/locales/doorkeeper.en.yml
@@ -60,6 +60,7 @@ en:
     scopes:
       api: Access your API
       read_user: Read user information
+      openid: Authenticate using OpenID Connect
 
     flash:
       applications:
diff --git a/config/routes.rb b/config/routes.rb
index 06293316937..1a851da6203 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -22,6 +22,8 @@ Rails.application.routes.draw do
                 authorizations: 'oauth/authorizations'
   end
 
+  use_doorkeeper_openid_connect
+
   # Autocomplete
   get '/autocomplete/users' => 'autocomplete#users'
   get '/autocomplete/users/:id' => 'autocomplete#user'
diff --git a/db/migrate/20161209165216_create_doorkeeper_openid_connect_tables.rb b/db/migrate/20161209165216_create_doorkeeper_openid_connect_tables.rb
new file mode 100644
index 00000000000..e63d5927f86
--- /dev/null
+++ b/db/migrate/20161209165216_create_doorkeeper_openid_connect_tables.rb
@@ -0,0 +1,37 @@
+class CreateDoorkeeperOpenidConnectTables < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    create_table :oauth_openid_requests do |t|
+      t.integer :access_grant_id, null: false
+      t.string :nonce, null: false
+    end
+
+    if Gitlab::Database.postgresql?
+      # add foreign key without validation to avoid downtime on PostgreSQL,
+      # also see db/post_migrate/20170209140523_validate_foreign_keys_on_oauth_openid_requests.rb
+      execute %q{
+        ALTER TABLE "oauth_openid_requests"
+          ADD CONSTRAINT "fk_oauth_openid_requests_oauth_access_grants_access_grant_id"
+          FOREIGN KEY ("access_grant_id")
+          REFERENCES "oauth_access_grants" ("id")
+          NOT VALID;
+      }
+    else
+      execute %q{
+        ALTER TABLE oauth_openid_requests
+          ADD CONSTRAINT fk_oauth_openid_requests_oauth_access_grants_access_grant_id
+          FOREIGN KEY (access_grant_id)
+          REFERENCES oauth_access_grants (id);
+      }
+    end
+  end
+
+  def down
+    drop_table :oauth_openid_requests
+  end
+end
diff --git a/db/post_migrate/20170209140523_validate_foreign_keys_on_oauth_openid_requests.rb b/db/post_migrate/20170209140523_validate_foreign_keys_on_oauth_openid_requests.rb
new file mode 100644
index 00000000000..e206f9af636
--- /dev/null
+++ b/db/post_migrate/20170209140523_validate_foreign_keys_on_oauth_openid_requests.rb
@@ -0,0 +1,20 @@
+class ValidateForeignKeysOnOauthOpenidRequests < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    if Gitlab::Database.postgresql?
+      execute %q{
+        ALTER TABLE "oauth_openid_requests"
+          VALIDATE CONSTRAINT "fk_oauth_openid_requests_oauth_access_grants_access_grant_id";
+      }
+    end
+  end
+
+  def down
+    # noop
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 624cf9432d0..8984ab3aac1 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -878,6 +878,11 @@ ActiveRecord::Schema.define(version: 20170306170512) do
   add_index "oauth_applications", ["owner_id", "owner_type"], name: "index_oauth_applications_on_owner_id_and_owner_type", using: :btree
   add_index "oauth_applications", ["uid"], name: "index_oauth_applications_on_uid", unique: true, using: :btree
 
+  create_table "oauth_openid_requests", force: :cascade do |t|
+    t.integer "access_grant_id", null: false
+    t.string "nonce", null: false
+  end
+
   create_table "pages_domains", force: :cascade do |t|
     t.integer "project_id"
     t.text "certificate"
@@ -1374,6 +1379,7 @@ ActiveRecord::Schema.define(version: 20170306170512) do
   add_foreign_key "merge_request_metrics", "merge_requests", on_delete: :cascade
   add_foreign_key "merge_requests_closing_issues", "issues", on_delete: :cascade
   add_foreign_key "merge_requests_closing_issues", "merge_requests", on_delete: :cascade
+  add_foreign_key "oauth_openid_requests", "oauth_access_grants", column: "access_grant_id", name: "fk_oauth_openid_requests_oauth_access_grants_access_grant_id"
   add_foreign_key "personal_access_tokens", "users"
   add_foreign_key "project_authorizations", "projects", on_delete: :cascade
   add_foreign_key "project_authorizations", "users", on_delete: :cascade
diff --git a/doc/integration/README.md b/doc/integration/README.md
index 22bdf33443d..e56e58498a6 100644
--- a/doc/integration/README.md
+++ b/doc/integration/README.md
@@ -12,6 +12,7 @@ See the documentation below for details on how to configure these services.
 - [SAML](saml.md) Configure GitLab as a SAML 2.0 Service Provider
 - [CAS](cas.md) Configure GitLab to sign in using CAS
 - [OAuth2 provider](oauth_provider.md) OAuth2 application creation
+- [OpenID Connect](openid_connect_provider.md) Use GitLab as an identity provider
 - [Gmail actions buttons](gmail_action_buttons_for_gitlab.md) Adds GitLab actions to messages
 - [reCAPTCHA](recaptcha.md) Configure GitLab to use Google reCAPTCHA for new users
 - [Akismet](akismet.md) Configure Akismet to stop spam
diff --git a/doc/integration/openid_connect_provider.md b/doc/integration/openid_connect_provider.md
new file mode 100644
index 00000000000..56f367d841e
--- /dev/null
+++ b/doc/integration/openid_connect_provider.md
@@ -0,0 +1,47 @@
+# GitLab as OpenID Connect identity provider
+
+This document is about using GitLab as an OpenID Connect identity provider
+to sign in to other services.
+
+## Introduction to OpenID Connect
+
+[OpenID Connect] \(OIC) is a simple identity layer on top of the
+OAuth 2.0 protocol. It allows clients to verify the identity of the end-user
+based on the authentication performed by GitLab, as well as to obtain
+basic profile information about the end-user in an interoperable and
+REST-like manner. OIC performs many of the same tasks as OpenID 2.0,
+but does so in a way that is API-friendly, and usable by native and
+mobile applications.
+
+On the client side, you can use [omniauth-openid-connect] for Rails
+applications, or any of the other available [client implementations].
+
+GitLab's implementation uses the [doorkeeper-openid_connect] gem, refer
+to its README for more details about which parts of the specifications
+are supported.
+
+## Enabling OpenID Connect for OAuth applications
+
+Refer to the [OAuth guide] for basic information on how to set up OAuth
+applications in GitLab. To enable OIC for an application, all you have to do
+is select the `openid` scope in the application settings.
+
+Currently the following user information is shared with clients:
+
+| Claim            | Type      | Description |
+|:-----------------|:----------|:------------|
+| `sub`            | `string`  | An opaque token that uniquely identifies the user
+| `auth_time`      | `integer` | The timestamp for the user's last authentication
+| `name`           | `string`  | The user's full name
+| `nickname`       | `string`  | The user's GitLab username
+| `email`          | `string`  | The user's public email address
+| `email_verified` | `boolean` | Whether the user's public email address was verified
+| `website`        | `string`  | URL for the user's website
+| `profile`        | `string`  | URL for the user's GitLab profile
+| `picture`        | `string`  | URL for the user's GitLab avatar
+
+[OpenID Connect]: http://openid.net/connect/ "OpenID Connect website"
+[doorkeeper-openid_connect]: https://github.com/doorkeeper-gem/doorkeeper-openid_connect "Doorkeeper::OpenidConnect website"
+[OAuth guide]: oauth_provider.md "GitLab as OAuth2 authentication service provider"
+[omniauth-openid-connect]: https://github.com/jjbohn/omniauth-openid-connect/ "OmniAuth::OpenIDConnect website"
+[client implementations]: http://openid.net/developers/libraries#connect "List of available client implementations"
diff --git a/lib/gitlab/auth.rb b/lib/gitlab/auth.rb
index 0a0bd0e781c..6166f8d0dd9 100644
--- a/lib/gitlab/auth.rb
+++ b/lib/gitlab/auth.rb
@@ -2,7 +2,7 @@ module Gitlab
   module Auth
     MissingPersonalTokenError = Class.new(StandardError)
 
-    SCOPES = [:api, :read_user].freeze
+    SCOPES = [:api, :read_user, :openid, :profile, :email].freeze
     DEFAULT_SCOPES = [:api].freeze
     OPTIONAL_SCOPES = SCOPES - DEFAULT_SCOPES
 
diff --git a/spec/factories/oauth_access_grants.rb b/spec/factories/oauth_access_grants.rb
new file mode 100644
index 00000000000..543b3e99274
--- /dev/null
+++ b/spec/factories/oauth_access_grants.rb
@@ -0,0 +1,11 @@
+FactoryGirl.define do
+  factory :oauth_access_grant do
+    resource_owner_id { create(:user).id }
+    application
+    token { Doorkeeper::OAuth::Helpers::UniqueToken.generate }
+    expires_in 2.hours
+
+    redirect_uri { application.redirect_uri }
+    scopes { application.scopes }
+  end
+end
diff --git a/spec/factories/oauth_access_tokens.rb b/spec/factories/oauth_access_tokens.rb
index ccf02d0719b..a46bc1d8ce8 100644
--- a/spec/factories/oauth_access_tokens.rb
+++ b/spec/factories/oauth_access_tokens.rb
@@ -2,6 +2,7 @@ FactoryGirl.define do
   factory :oauth_access_token do
     resource_owner
     application
-    token '123456'
+    token { Doorkeeper::OAuth::Helpers::UniqueToken.generate }
+    scopes { application.scopes }
   end
 end
diff --git a/spec/factories/oauth_applications.rb b/spec/factories/oauth_applications.rb
index d116a573830..86cdc208268 100644
--- a/spec/factories/oauth_applications.rb
+++ b/spec/factories/oauth_applications.rb
@@ -1,7 +1,7 @@
 FactoryGirl.define do
   factory :oauth_application, class: 'Doorkeeper::Application', aliases: [:application] do
     name { FFaker::Name.name }
-    uid { FFaker::Name.name }
+    uid { Doorkeeper::OAuth::Helpers::UniqueToken.generate }
     redirect_uri { FFaker::Internet.uri('http') }
     owner
     owner_type 'User'
diff --git a/spec/initializers/secret_token_spec.rb b/spec/initializers/secret_token_spec.rb
index ad7f032d1e5..65c97da2efd 100644
--- a/spec/initializers/secret_token_spec.rb
+++ b/spec/initializers/secret_token_spec.rb
@@ -6,6 +6,9 @@ describe 'create_tokens', lib: true do
 
   let(:secrets) { ActiveSupport::OrderedOptions.new }
 
+  HEX_KEY = /\h{128}/
+  RSA_KEY = /\A-----BEGIN RSA PRIVATE KEY-----\n.+\n-----END RSA PRIVATE KEY-----\n\Z/m
+
   before do
     allow(File).to receive(:write)
     allow(File).to receive(:delete)
@@ -15,7 +18,7 @@ describe 'create_tokens', lib: true do
     allow(self).to receive(:exit)
   end
 
-  context 'setting secret_key_base and otp_key_base' do
+  context 'setting secret keys' do
     context 'when none of the secrets exist' do
       before do
         stub_env('SECRET_KEY_BASE', nil)
@@ -24,19 +27,29 @@ describe 'create_tokens', lib: true do
         allow(self).to receive(:warn_missing_secret)
       end
 
-      it 'generates different secrets for secret_key_base, otp_key_base, and db_key_base' do
+      it 'generates different hashes for secret_key_base, otp_key_base, and db_key_base' do
         create_tokens
 
         keys = secrets.values_at(:secret_key_base, :otp_key_base, :db_key_base)
 
         expect(keys.uniq).to eq(keys)
-        expect(keys.map(&:length)).to all(eq(128))
+        expect(keys).to all(match(HEX_KEY))
+      end
+
+      it 'generates an RSA key for jws_private_key' do
+        create_tokens
+
+        keys = secrets.values_at(:jws_private_key)
+
+        expect(keys.uniq).to eq(keys)
+        expect(keys).to all(match(RSA_KEY))
       end
 
       it 'warns about the secrets to add to secrets.yml' do
         expect(self).to receive(:warn_missing_secret).with('secret_key_base')
         expect(self).to receive(:warn_missing_secret).with('otp_key_base')
         expect(self).to receive(:warn_missing_secret).with('db_key_base')
+        expect(self).to receive(:warn_missing_secret).with('jws_private_key')
 
         create_tokens
       end
@@ -48,6 +61,7 @@ describe 'create_tokens', lib: true do
           expect(new_secrets['secret_key_base']).to eq(secrets.secret_key_base)
           expect(new_secrets['otp_key_base']).to eq(secrets.otp_key_base)
           expect(new_secrets['db_key_base']).to eq(secrets.db_key_base)
+          expect(new_secrets['jws_private_key']).to eq(secrets.jws_private_key)
         end
 
         create_tokens
@@ -63,6 +77,7 @@ describe 'create_tokens', lib: true do
     context 'when the other secrets all exist' do
       before do
         secrets.db_key_base = 'db_key_base'
+        secrets.jws_private_key = 'jws_private_key'
 
         allow(File).to receive(:exist?).with('.secret').and_return(true)
         allow(File).to receive(:read).with('.secret').and_return('file_key')
@@ -73,6 +88,7 @@ describe 'create_tokens', lib: true do
           stub_env('SECRET_KEY_BASE', 'env_key')
           secrets.secret_key_base = 'secret_key_base'
           secrets.otp_key_base = 'otp_key_base'
+          secrets.jws_private_key = 'jws_private_key'
         end
 
         it 'does not issue a warning' do
@@ -98,6 +114,7 @@ describe 'create_tokens', lib: true do
         before do
           secrets.secret_key_base = 'secret_key_base'
           secrets.otp_key_base = 'otp_key_base'
+          secrets.jws_private_key = 'jws_private_key'
         end
 
         it 'does not write any files' do
@@ -112,6 +129,7 @@ describe 'create_tokens', lib: true do
           expect(secrets.secret_key_base).to eq('secret_key_base')
           expect(secrets.otp_key_base).to eq('otp_key_base')
           expect(secrets.db_key_base).to eq('db_key_base')
+          expect(secrets.jws_private_key).to eq('jws_private_key')
         end
 
         it 'deletes the .secret file' do
@@ -135,6 +153,7 @@ describe 'create_tokens', lib: true do
             expect(new_secrets['secret_key_base']).to eq('file_key')
             expect(new_secrets['otp_key_base']).to eq('file_key')
             expect(new_secrets['db_key_base']).to eq('db_key_base')
+            expect(new_secrets['jws_private_key']).to eq('jws_private_key')
           end
 
           create_tokens
diff --git a/spec/requests/openid_connect_spec.rb b/spec/requests/openid_connect_spec.rb
new file mode 100644
index 00000000000..5206634bca5
--- /dev/null
+++ b/spec/requests/openid_connect_spec.rb
@@ -0,0 +1,134 @@
+require 'spec_helper'
+
+describe 'OpenID Connect requests' do
+  include ApiHelpers
+
+  let(:user) { create :user }
+  let(:access_grant) { create :oauth_access_grant, application: application, resource_owner_id: user.id }
+  let(:access_token) { create :oauth_access_token, application: application, resource_owner_id: user.id }
+
+  def request_access_token
+    login_as user
+
+    post '/oauth/token',
+      grant_type: 'authorization_code',
+      code: access_grant.token,
+      redirect_uri: application.redirect_uri,
+      client_id: application.uid,
+      client_secret: application.secret
+  end
+
+  def request_user_info
+    get '/oauth/userinfo', nil, 'Authorization' => "Bearer #{access_token.token}"
+  end
+
+  def hashed_subject
+    Digest::SHA256.hexdigest("#{user.id}-#{Rails.application.secrets.secret_key_base}")
+  end
+
+  context 'Application without OpenID scope' do
+    let(:application) { create :oauth_application, scopes: 'api' }
+
+    it 'token response does not include an ID token' do
+      request_access_token
+
+      expect(json_response).to include 'access_token'
+      expect(json_response).not_to include 'id_token'
+    end
+
+    it 'userinfo response is unauthorized' do
+      request_user_info
+
+      expect(response).to have_http_status 403
+      expect(response.body).to be_blank
+    end
+  end
+
+  context 'Application with OpenID scope' do
+    let(:application) { create :oauth_application, scopes: 'openid' }
+
+    it 'token response includes an ID token' do
+      request_access_token
+
+      expect(json_response).to include 'id_token'
+    end
+
+    context 'UserInfo payload' do
+      let(:user) do
+        create(
+          :user,
+          name: 'Alice',
+          username: 'alice',
+          emails: [private_email, public_email],
+          email: private_email.email,
+          public_email: public_email.email,
+          website_url: 'https://example.com',
+          avatar: fixture_file_upload(Rails.root + "spec/fixtures/dk.png"),
+        )
+      end
+
+      let(:public_email) { build :email, email: 'public@example.com' }
+      let(:private_email) { build :email, email: 'private@example.com' }
+
+      it 'includes all user information' do
+        request_user_info
+
+        expect(json_response).to eq({
+          'sub'            => hashed_subject,
+          'name'           => 'Alice',
+          'nickname'       => 'alice',
+          'email'          => 'public@example.com',
+          'email_verified' => true,
+          'website'        => 'https://example.com',
+          'profile'        => 'http://localhost/alice',
+          'picture'        => "http://localhost/uploads/user/avatar/#{user.id}/dk.png",
+        })
+      end
+    end
+
+    context 'ID token payload' do
+      before do
+        request_access_token
+        @payload = JSON::JWT.decode(json_response['id_token'], :skip_verification)
+      end
+
+      it 'includes the Gitlab root URL' do
+        expect(@payload['iss']).to eq Gitlab.config.gitlab.url
+      end
+
+      it 'includes the hashed user ID' do
+        expect(@payload['sub']).to eq hashed_subject
+      end
+
+      it 'includes the time of the last authentication' do
+        expect(@payload['auth_time']).to eq user.current_sign_in_at.to_i
+      end
+
+      it 'does not include any unknown properties' do
+        expect(@payload.keys).to eq %w[iss sub aud exp iat auth_time]
+      end
+    end
+
+    context 'when user is blocked' do
+      it 'returns authentication error' do
+        access_grant
+        user.block
+
+        expect do
+          request_access_token
+        end.to throw_symbol :warden
+      end
+    end
+
+    context 'when user is ldap_blocked' do
+      it 'returns authentication error' do
+        access_grant
+        user.ldap_block
+
+        expect do
+          request_access_token
+        end.to throw_symbol :warden
+      end
+    end
+  end
+end
diff --git a/spec/routing/openid_connect_spec.rb b/spec/routing/openid_connect_spec.rb
new file mode 100644
index 00000000000..2c3bc08f1a1
--- /dev/null
+++ b/spec/routing/openid_connect_spec.rb
@@ -0,0 +1,30 @@
+require 'spec_helper'
+
+# oauth_discovery_keys      GET /oauth/discovery/keys(.:format)             doorkeeper/openid_connect/discovery#keys
+# oauth_discovery_provider  GET /.well-known/openid-configuration(.:format) doorkeeper/openid_connect/discovery#provider
+# oauth_discovery_webfinger GET /.well-known/webfinger(.:format)            doorkeeper/openid_connect/discovery#webfinger
+describe Doorkeeper::OpenidConnect::DiscoveryController, 'routing' do
+  it "to #provider" do
+    expect(get('/.well-known/openid-configuration')).to route_to('doorkeeper/openid_connect/discovery#provider')
+  end
+
+  it "to #webfinger" do
+    expect(get('/.well-known/webfinger')).to route_to('doorkeeper/openid_connect/discovery#webfinger')
+  end
+
+  it "to #keys" do
+    expect(get('/oauth/discovery/keys')).to route_to('doorkeeper/openid_connect/discovery#keys')
+  end
+end
+
+# oauth_userinfo GET  /oauth/userinfo(.:format) doorkeeper/openid_connect/userinfo#show
+#                POST /oauth/userinfo(.:format) doorkeeper/openid_connect/userinfo#show
+describe Doorkeeper::OpenidConnect::UserinfoController, 'routing' do
+  it "to #show" do
+    expect(get('/oauth/userinfo')).to route_to('doorkeeper/openid_connect/userinfo#show')
+  end
+
+  it "to #show" do
+    expect(post('/oauth/userinfo')).to route_to('doorkeeper/openid_connect/userinfo#show')
+  end
+end