Multi-factor authentication (#1817)

* Initial pass

* Tests for MFA and locale cleanup

* Brakeman

* Update two-factor authentication status styling

* Update app/models/user.rb

Co-authored-by: Zach Gollwitzer <zach@maybe.co>
Signed-off-by: Josh Pigford <josh@joshpigford.com>

* Refactor MFA verification and session handling in tests

---------

Signed-off-by: Josh Pigford <josh@joshpigford.com>
Co-authored-by: Zach Gollwitzer <zach@maybe.co>

app/controllers/mfa_controller.rb

@@ -0,0 +1,53 @@
+class MfaController < ApplicationController
+  layout :determine_layout
+  skip_authentication only: [ :verify, :verify_code ]
+
+  def new
+    redirect_to root_path if Current.user.otp_required?
+    Current.user.setup_mfa! unless Current.user.otp_secret.present?
+  end
+
+  def create
+    if Current.user.verify_otp?(params[:code])
+      Current.user.enable_mfa!
+      @backup_codes = Current.user.otp_backup_codes
+      render :backup_codes
+    else
+      Current.user.disable_mfa!
+      redirect_to new_mfa_path, alert: t(".invalid_code")
+    end
+  end
+
+  def verify
+    @user = User.find_by(id: session[:mfa_user_id])
+    redirect_to new_session_path unless @user
+  end
+
+  def verify_code
+    @user = User.find_by(id: session[:mfa_user_id])
+
+    if @user&.verify_otp?(params[:code])
+      session.delete(:mfa_user_id)
+      @session = create_session_for(@user)
+      redirect_to root_path
+    else
+      flash.now[:alert] = t(".invalid_code")
+      render :verify, status: :unprocessable_entity
+    end
+  end
+
+  def disable
+    Current.user.disable_mfa!
+    redirect_to settings_security_path, notice: t(".success")
+  end
+
+  private
+
+    def determine_layout
+      if action_name.in?(%w[verify verify_code])
+        "auth"
+      else
+        "with_sidebar"
+      end
+    end
+end

app/controllers/sessions_controller.rb

@@ -9,8 +9,13 @@ class SessionsController < ApplicationController
 
   def create
     if user = User.authenticate_by(email: params[:email], password: params[:password])
-      @session = create_session_for(user)
-      redirect_to root_path
+      if user.otp_required?
+        session[:mfa_user_id] = user.id
+        redirect_to verify_mfa_path
+      else
+        @session = create_session_for(user)
+        redirect_to root_path
+      end
     else
       flash.now[:alert] = t(".invalid_credentials")
       render :new, status: :unprocessable_entity

app/controllers/settings/securities_controller.rb

@@ -0,0 +1,4 @@
+class Settings::SecuritiesController < SettingsController
+  def show
+  end
+end

app/helpers/application_helper.rb

@@ -19,6 +19,10 @@ module ApplicationHelper
     content_for(:header_title) { page_title }
   end
 
+  def header_description(page_description)
+    content_for(:header_description) { page_description }
+  end
+
   def family_notifications_stream
     turbo_stream_from [ Current.family, :notifications ] if Current.family
   end

app/helpers/mfa_helper.rb

@@ -0,0 +1,20 @@
+module MfaHelper
+  def generate_mfa_qr_code(provisioning_uri)
+    qr_code = RQRCode::QRCode.new(provisioning_uri).as_svg(
+      color: "141414",
+      module_size: 4,
+      standalone: true,
+      use_path: true,
+      svg_attributes: {
+        width: "228",
+        height: "228",
+        viewBox: "0 0 57 57"
+      }
+    )
+
+    # Whitelist specific SVG attributes and elements that we know are safe
+    sanitize qr_code,
+      tags: %w[svg g path rect],
+      attributes: %w[viewBox height width fill stroke stroke-width d x y class]
+  end
+end

app/helpers/settings_helper.rb

@@ -3,6 +3,7 @@ module SettingsHelper
     { name: I18n.t("settings.nav.profile_label"), path: :settings_profile_path },
     { name: I18n.t("settings.nav.preferences_label"), path: :settings_preferences_path },
     { name: I18n.t("settings.nav.self_hosting_label"), path: :settings_hosting_path, condition: :self_hosted? },
+    { name: I18n.t("settings.nav.security_label"), path: :settings_security_path },
     { name: I18n.t("settings.nav.billing_label"), path: :settings_billing_path },
     { name: I18n.t("settings.nav.accounts_label"), path: :accounts_path },
     { name: I18n.t("settings.nav.imports_label"), path: :imports_path },

app/models/user.rb

@@ -110,6 +110,41 @@ class User < ApplicationRecord
     end
   end
 
+  # MFA
+  def setup_mfa!
+    update!(
+      otp_secret: ROTP::Base32.random(32),
+      otp_required: false,
+      otp_backup_codes: []
+    )
+  end
+
+  def enable_mfa!
+    update!(
+      otp_required: true,
+      otp_backup_codes: generate_backup_codes
+    )
+  end
+
+  def disable_mfa!
+    update!(
+      otp_secret: nil,
+      otp_required: false,
+      otp_backup_codes: []
+    )
+  end
+
+  def verify_otp?(code)
+    return false if otp_secret.blank?
+    return true if verify_backup_code?(code)
+    totp.verify(code, drift_behind: 15)
+  end
+
+  def provisioning_uri
+    return nil unless otp_secret.present?
+    totp.provisioning_uri(email)
+  end
+
   private
     def ensure_valid_profile_image
       return unless profile_image.attached?
@@ -133,4 +168,26 @@ class User < ApplicationRecord
         errors.add(:profile_image, :invalid_file_size, max_megabytes: 10)
       end
     end
+
+    def totp
+      ROTP::TOTP.new(otp_secret, issuer: "Maybe Finance")
+    end
+
+    def verify_backup_code?(code)
+      return false if otp_backup_codes.blank?
+
+      # Find and remove the used backup code
+      if (index = otp_backup_codes.index(code))
+        remaining_codes = otp_backup_codes.dup
+        remaining_codes.delete_at(index)
+        update_column(:otp_backup_codes, remaining_codes)
+        true
+      else
+        false
+      end
+    end
+
+    def generate_backup_codes
+      8.times.map { SecureRandom.hex(4) }
+    end
 end

app/views/mfa/backup_codes.html.erb

@@ -0,0 +1,29 @@
+<%
+  header_title t(".title")
+  header_description t(".description")
+%>
+
+<% content_for :sidebar do %>
+  <%= render "settings/nav" %>
+<% end %>
+
+<div class="space-y-4">
+  <h1 class="text-gray-900 text-xl font-medium mb-4"><%= t(".page_title") %></h1>
+  <%= settings_section title: t(".backup_codes_title"), subtitle: t(".backup_codes_description") do %>
+    <div class="space-y-6">
+      <div class="grid grid-cols-2 gap-4">
+        <% @backup_codes.each do |code| %>
+          <div class="p-3 bg-gray-100 rounded-lg font-mono text-lg">
+            <%= code %>
+          </div>
+        <% end %>
+      </div>
+
+      <div class="mt-6">
+        <%= link_to t(".continue"), settings_security_path, class: "w-full btn btn--primary" %>
+      </div>
+    </div>
+  <% end %>
+
+  <%= settings_nav_footer %>
+</div> 

app/views/mfa/new.html.erb

@@ -0,0 +1,45 @@
+<%
+  header_title t(".title")
+  header_description t(".description")
+%>
+
+<% content_for :sidebar do %>
+  <%= render "settings/nav" %>
+<% end %>
+
+<div class="space-y-4">
+  <h1 class="text-gray-900 text-xl font-medium mb-4"><%= t(".page_title") %></h1>
+  <%= settings_section title: t(".scan_title"), subtitle: t(".scan_description") do %>
+    <div class="space-y-6">
+      <div>
+        <%= generate_mfa_qr_code(Current.user.provisioning_uri) %>
+      </div>
+
+      <div>
+        <h3 class="text-lg font-medium leading-6 text-gray-900"><%= t(".verify_title") %></h3>
+        <div class="mt-2 text-sm text-gray-500">
+          <p><%= t(".verify_description") %></p>
+        </div>
+      </div>
+
+      <%= styled_form_with url: mfa_path, method: :post, class: "mt-5", data: { turbo: false } do |f| %>
+        <div>
+          <%= f.text_field :code,
+            required: true,
+            autofocus: true,
+            autocomplete: "one-time-code",
+            inputmode: "numeric",
+            pattern: "[0-9]*",
+            label: t(".code_label"),
+            placeholder: t(".code_placeholder") %>
+
+          <div class="flex justify-end mt-4">
+            <%= f.submit t(".verify_button"), class: "bg-gray-900 hover:bg-gray-700 cursor-pointer text-white rounded-lg px-3 py-2" %>
+          </div>
+        </div>
+      <% end %>
+    </div>
+  <% end %>
+
+  <%= settings_nav_footer %>
+</div>

app/views/mfa/verify.html.erb

@@ -0,0 +1,14 @@
+<%
+  header_title t(".title")
+  header_description t(".description")
+%>
+
+<%= styled_form_with url: verify_mfa_path, method: :post, class: "space-y-4" do |form| %>
+  <%= form.text_field :code,
+    required: true,
+    autofocus: true,
+    autocomplete: "one-time-code",
+    label: t(".page_title") %>
+
+  <%= form.submit t(".verify_button") %>
+<% end %>

app/views/settings/_nav.html.erb

@@ -21,6 +21,9 @@
         <li>
           <%= sidebar_link_to t(".preferences_label"), settings_preferences_path, icon: "bolt" %>
         </li>
+        <li>
+          <%= sidebar_link_to t(".security_label"), settings_security_path, icon: "shield-check" %>
+        </li>
         <% if self_hosted? %>
           <li>
             <%= sidebar_link_to t(".self_hosting_label"), settings_hosting_path, icon: "database" %>

app/views/settings/securities/show.html.erb

@@ -0,0 +1,45 @@
+<% content_for :sidebar do %>
+  <%= render "settings/nav" %>
+<% end %>
+
+<div class="space-y-4">
+  <h1 class="text-gray-900 text-xl font-medium mb-4"><%= t(".page_title") %></h1>
+  <%= settings_section title: t(".mfa_title"), subtitle: t(".mfa_description") do %>
+    <div class="space-y-4">
+      <div class="p-3 shadow-xs bg-white border border-alpha-black-200 rounded-lg flex justify-between items-center">
+        <div class="flex items-center gap-3">
+          <div class="w-9 h-9 rounded-full bg-gray-25 flex justify-center items-center">
+            <%= lucide_icon "shield-check", class: "w-5 h-5 text-gray-500" %>
+          </div>
+
+          <div class="text-sm space-y-1">
+            <% if Current.user.otp_required? %>
+              <p class="text-gray-900">Two-factor authentication is <span class="font-medium text-green-600">enabled</span></p>
+              <p class="text-gray-500">Your account is protected with an additional layer of security.</p>
+            <% else %>
+              <p class="text-gray-900">Two-factor authentication is <span class="font-medium text-red-600">disabled</span></p>
+              <p class="text-gray-500">Enable 2FA to add an extra layer of security to your account.</p>
+            <% end %>
+          </div>
+        </div>
+
+        <% if Current.user.otp_required? %>
+          <%= button_to t(".disable_mfa"), disable_mfa_path, 
+            method: :delete,
+            class: "btn btn--secondary flex items-center gap-1",
+            data: { turbo_confirm: {
+              title: t(".disable_mfa_confirm"),
+              body: t(".disable_mfa_confirm"),
+              accept: t(".disable_mfa"),
+              acceptClass: "w-full bg-red-500 text-white rounded-xl text-center p-[10px] border mb-2"
+            } } %>
+        <% else %>
+          <%= link_to t(".enable_mfa"), new_mfa_path,
+            class: "btn btn--primary flex items-center gap-1" %>
+        <% end %>
+      </div>
+    </div>
+  <% end %>
+
+  <%= settings_nav_footer %>
+</div>