Add WebAuthn as an alternative 2FA method (#14466)

* feat: add possibility of adding WebAuthn security keys to use as 2FA

This adds a basic UI for enabling WebAuthn 2FA. We did a little refactor
to the Settings page for editing the 2FA methods – now it will list the
methods that are available to the user (TOTP and WebAuthn) and from
there they'll be able to add or remove any of them.
Also, it's worth mentioning that for enabling WebAuthn it's required to
have TOTP enabled, so the first time that you go to the 2FA Settings
page, you'll be asked to set it up.
This work was inspired by the one donde by Github in their platform, and
despite it could be approached in different ways, we decided to go with
this one given that we feel that this gives a great UX.

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* feat: add request for WebAuthn as second factor at login if enabled

This commits adds the feature for using WebAuthn as a second factor for
login when enabled.
If users have WebAuthn enabled, now a page requesting for the use of a
WebAuthn credential for log in will appear, although a link redirecting
to the old page for logging in using a two-factor code will also be
present.

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* feat: add possibility of deleting WebAuthn Credentials

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* feat: disable WebAuthn when an Admin disables 2FA for a user

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* feat: remove ability to disable TOTP leaving only WebAuthn as 2FA

Following examples form other platforms like Github, we decided to make
Webauthn 2FA secondary to 2FA with TOTP, so that we removed the
possibility of removing TOTP authentication only, leaving users with
just WEbAuthn as 2FA. Instead, users will have to click on 'Disable 2FA'
in order to remove second factor auth.
The reason for WebAuthn being secondary to TOPT is that in that way,
users will still be able to log in using their code from their phone's
application if they don't have their security keys with them – or maybe
even lost them.

* We had to change a little the flow for setting up TOTP, given that now
  it's possible to setting up again if you already had TOTP, in order to
  let users modify their authenticator app – given that now it's not
  possible for them to disable TOTP and set it up again with another
  authenticator app.
  So, basically, now instead of storing the new `otp_secret` in the
  user, we store it in the session until the process of set up is
  finished.
  This was because, as it was before, when users clicked on 'Edit' in
  the new two-factor methods lists page, but then went back without
  finishing the flow, their `otp_secret` had been changed therefore
  invalidating their previous authenticator app, making them unable to
  log in again using TOTP.

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

* refactor: fix eslint errors

The PR build was failing given that linting returning some errors.
This commit attempts to fix them.

* refactor: normalize i18n translations

The build was failing given that i18n translations files were not
normalized.
This commits fixes that.

* refactor: avoid having the webauthn gem locked to a specific version

* refactor: use symbols for routes without '/'

* refactor: avoid sending webauthn disabled email when 2FA is disabled

When an admins disable 2FA for users, we were sending two mails
to them, one notifying that 2FA was disabled and the other to notify
that WebAuthn was disabled.
As the second one is redundant since the first email includes it, we can
remove it and send just one email to users.

* refactor: avoid creating new env variable for webauthn_origin config

* refactor: improve flash error messages for webauthn pages

Co-authored-by: Facundo Padula <facundo.padula@cedarcode.com>

1 files changed, 374 insertions, 0 deletions

diff --git a/spec/controllers/settings/two_factor_authentication/webauthn_credentials_controller_spec.rb b/spec/controllers/settings/two_factor_authentication/webauthn_credentials_controller_spec.rb
new file mode 100644
index 000000000..fe53b4dfc
--- /dev/null
+++ b/spec/controllers/settings/two_factor_authentication/webauthn_credentials_controller_spec.rb
@@ -0,0 +1,374 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require 'webauthn/fake_client'
+
+describe Settings::TwoFactorAuthentication::WebauthnCredentialsController do
+  render_views
+
+  let(:user) { Fabricate(:user) }
+  let(:domain) { "#{Rails.configuration.x.use_https ? 'https' : 'http' }://#{Rails.configuration.x.web_domain}" }
+  let(:fake_client) { WebAuthn::FakeClient.new(domain) }
+
+  def add_webauthn_credential(user)
+    Fabricate(:webauthn_credential, user_id: user.id, nickname: 'USB Key')
+  end
+
+  describe 'GET #new' do
+    context 'when signed in' do
+      before do
+        sign_in user, scope: :user
+      end
+
+      context 'when user has otp enabled' do
+        before do
+          user.update(otp_required_for_login: true)
+        end
+
+        it 'returns http success' do
+          get :new
+
+          expect(response).to have_http_status(200)
+        end
+      end
+
+      context 'when user does not have otp enabled' do
+        before do
+          user.update(otp_required_for_login: false)
+        end
+
+        it 'requires otp enabled first' do
+          get :new
+
+          expect(response).to redirect_to settings_two_factor_authentication_methods_path
+          expect(flash[:error]).to be_present
+        end
+      end
+    end
+  end
+
+  describe 'GET #index' do
+    context 'when signed in' do
+      before do
+        sign_in user, scope: :user
+      end
+
+      context 'when user has otp enabled' do
+        before do
+          user.update(otp_required_for_login: true)
+        end
+
+        context 'when user has webauthn enabled' do
+          before do
+            user.update(webauthn_id: WebAuthn.generate_user_id)
+            add_webauthn_credential(user)
+          end
+
+          it 'returns http success' do
+            get :index
+
+            expect(response).to have_http_status(200)
+          end
+        end
+
+        context 'when user does not has webauthn enabled' do
+          it 'redirects to 2FA methods list page' do
+            get :index
+
+            expect(response).to redirect_to settings_two_factor_authentication_methods_path
+            expect(flash[:error]).to be_present
+          end
+        end
+      end
+
+      context 'when user does not have otp enabled' do
+        before do
+          user.update(otp_required_for_login: false)
+        end
+
+        it 'requires otp enabled first' do
+          get :index
+
+          expect(response).to redirect_to settings_two_factor_authentication_methods_path
+          expect(flash[:error]).to be_present
+        end
+      end
+    end
+
+    context 'when not signed in' do
+      it 'redirects to login' do
+        delete :index
+
+        expect(response).to redirect_to new_user_session_path
+      end
+    end
+  end
+
+  describe 'GET /options #options' do
+    context 'when signed in' do
+      before do
+        sign_in user, scope: :user
+      end
+
+      context 'when user has otp enabled' do
+        before do
+          user.update(otp_required_for_login: true)
+        end
+
+        context 'when user has webauthn enabled' do
+          before do
+            user.update(webauthn_id: WebAuthn.generate_user_id)
+            add_webauthn_credential(user)
+          end
+
+          it 'returns http success' do
+            get :options
+
+            expect(response).to have_http_status(200)
+          end
+
+          it 'stores the challenge on the session' do
+            get :options
+
+            expect(@controller.session[:webauthn_challenge]).to be_present
+          end
+
+          it 'does not change webauthn_id' do
+            expect { get :options }.to_not change { user.webauthn_id }
+          end
+
+          it "includes existing credentials in list of excluded credentials" do
+            get :options
+
+            excluded_credentials_ids = JSON.parse(response.body)['excludeCredentials'].map { |credential| credential['id'] }
+            expect(excluded_credentials_ids).to match_array(user.webauthn_credentials.pluck(:external_id))
+          end
+        end
+
+        context 'when user does not have webauthn enabled' do
+          it 'returns http success' do
+            get :options
+
+            expect(response).to have_http_status(200)
+          end
+
+          it 'stores the challenge on the session' do
+            get :options
+
+            expect(@controller.session[:webauthn_challenge]).to be_present
+          end
+
+          it 'sets user webauthn_id' do
+            get :options
+
+            expect(user.reload.webauthn_id).to be_present
+          end
+        end
+      end
+
+      context 'when user has not enabled otp' do
+        before do
+          user.update(otp_required_for_login: false)
+        end
+
+        it 'requires otp enabled first' do
+          get :options
+
+          expect(response).to redirect_to settings_two_factor_authentication_methods_path
+          expect(flash[:error]).to be_present
+        end
+      end
+    end
+
+    context 'when not signed in' do
+      it 'redirects to login' do
+        get :options
+
+        expect(response).to redirect_to new_user_session_path
+      end
+    end
+  end
+
+  describe 'POST #create' do
+    let(:nickname) { 'SecurityKeyNickname' }
+
+    let(:challenge) do
+      WebAuthn::Credential.options_for_create(
+        user: { id: user.id, name: user.account.username, display_name: user.account.display_name }
+      ).challenge
+    end
+
+    let(:new_webauthn_credential) { fake_client.create(challenge: challenge) }
+
+    context 'when signed in' do
+      before do
+        sign_in user, scope: :user
+      end
+
+      context 'when user has enabled otp' do
+        before do
+          user.update(otp_required_for_login: true)
+        end
+
+        context 'when user has enabled webauthn' do
+          before do
+            user.update(webauthn_id: WebAuthn.generate_user_id)
+            add_webauthn_credential(user)
+          end
+
+          context 'when creation succeeds' do
+            it 'returns http success' do
+              @controller.session[:webauthn_challenge] = challenge
+
+              post :create, params: { credential: new_webauthn_credential, nickname: nickname }
+
+              expect(response).to have_http_status(200)
+            end
+
+            it 'adds a new credential to user credentials' do
+              @controller.session[:webauthn_challenge] = challenge
+
+              expect do
+                post :create, params: { credential: new_webauthn_credential, nickname: nickname }
+              end.to change { user.webauthn_credentials.count }.by(1)
+            end
+
+            it 'does not change webauthn_id' do
+              @controller.session[:webauthn_challenge] = challenge
+
+              expect do
+                post :create, params: { credential: new_webauthn_credential, nickname: nickname }
+              end.to_not change { user.webauthn_id }
+            end
+          end
+
+          context 'when the nickname is already used' do
+            it 'fails' do
+              @controller.session[:webauthn_challenge] = challenge
+
+              post :create, params: { credential: new_webauthn_credential, nickname: 'USB Key' }
+
+              expect(response).to have_http_status(500)
+              expect(flash[:error]).to be_present
+            end
+          end
+
+          context 'when the credential already exists' do
+            before do
+              user2 = Fabricate(:user)
+              public_key_credential = WebAuthn::Credential.from_create(new_webauthn_credential)
+              Fabricate(:webauthn_credential,
+                        user_id: user2.id,
+                        external_id: public_key_credential.id,
+                        public_key: public_key_credential.public_key)
+            end
+
+            it 'fails' do
+              @controller.session[:webauthn_challenge] = challenge
+
+              post :create, params: { credential: new_webauthn_credential, nickname: nickname }
+
+              expect(response).to have_http_status(500)
+              expect(flash[:error]).to be_present
+            end
+          end
+        end
+
+        context 'when user have not enabled webauthn' do
+          context 'creation succeeds' do
+            it 'creates a webauthn credential' do
+              @controller.session[:webauthn_challenge] = challenge
+
+              expect do
+                post :create, params: { credential: new_webauthn_credential, nickname: nickname }
+              end.to change { user.webauthn_credentials.count }.by(1)
+            end
+          end
+        end
+      end
+
+      context 'when user has not enabled otp' do
+        before do
+          user.update(otp_required_for_login: false)
+        end
+
+        it 'requires otp enabled first' do
+          post :create, params: { credential: new_webauthn_credential, nickname: nickname }
+
+          expect(response).to redirect_to settings_two_factor_authentication_methods_path
+          expect(flash[:error]).to be_present
+        end
+      end
+    end
+
+    context 'when not signed in' do
+      it 'redirects to login' do
+        post :create, params: { credential: new_webauthn_credential, nickname: nickname }
+
+        expect(response).to redirect_to new_user_session_path
+      end
+    end
+  end
+
+  describe 'DELETE #destroy' do
+    context 'when signed in' do
+      before do
+        sign_in user, scope: :user
+      end
+
+      context 'when user has otp enabled' do
+        before do
+          user.update(otp_required_for_login: true)
+        end
+
+        context 'when user has webauthn enabled' do
+          before do
+            user.update(webauthn_id: WebAuthn.generate_user_id)
+            add_webauthn_credential(user)
+          end
+
+          context 'when deletion succeeds' do
+            it 'redirects to 2FA methods list and shows flash success' do
+              delete :destroy, params: { id: user.webauthn_credentials.take.id }
+
+              expect(response).to redirect_to settings_two_factor_authentication_methods_path
+              expect(flash[:success]).to be_present
+            end
+
+            it 'deletes the credential' do
+              expect do
+                delete :destroy, params: { id: user.webauthn_credentials.take.id }
+              end.to change { user.webauthn_credentials.count }.by(-1)
+            end
+          end
+        end
+
+        context 'when user does not have webauthn enabled' do
+          it 'redirects to 2FA methods list and shows flash error' do
+            delete :destroy, params: { id: '1' }
+
+            expect(response).to redirect_to settings_two_factor_authentication_methods_path
+            expect(flash[:error]).to be_present
+          end
+        end
+      end
+
+      context 'when user does not have otp enabled' do
+        it 'requires otp enabled first' do
+          delete :destroy, params: { id: '1' }
+
+          expect(response).to redirect_to settings_two_factor_authentication_methods_path
+          expect(flash[:error]).to be_present
+        end
+      end
+    end
+
+    context 'when not signed in' do
+      it 'redirects to login' do
+        delete :destroy, params: { id: '1' }
+
+        expect(response).to redirect_to new_user_session_path
+      end
+    end
+  end
+end