add ability to use timestamp server

app/controllers/timestamp_server_controller.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+class TimestampServerController < ApplicationController
+  before_action :build_encrypted_config
+  authorize_resource :encrypted_config
+
+  def create
+    return head :not_found if Docuseal.multitenant?
+
+    test_timeserver_url(@encrypted_config.value) if @encrypted_config.value.present?
+
+    if @encrypted_config.value.present? ? @encrypted_config.save : @encrypted_config.delete
+      redirect_back fallback_location: settings_notifications_path, notice: 'Changes have been saved'
+    else
+      redirect_back fallback_location: settings_notifications_path, alert: 'Unable to save'
+    end
+  rescue HexaPDF::Error, SocketError, Submissions::TimestampHandler::TimestampError
+    redirect_back fallback_location: settings_notifications_path, alert: 'Invalid Timeserver'
+  end
+
+  private
+
+  def test_timeserver_url(url)
+    pdf = HexaPDF::Document.new
+    pdf.pages.add
+
+    pkcs = Accounts.load_signing_pkcs(current_account)
+
+    pdf.sign(StringIO.new,
+             reason: 'Test',
+             certificate: pkcs.certificate,
+             key: pkcs.key,
+             certificate_chain: pkcs.ca_certs || [],
+             timestamp_handler: Submissions::TimestampHandler.new(tsa_url: url))
+  end
+
+  def load_encrypted_config
+    @encrypted_config
+  end
+
+  def build_encrypted_config
+    @encrypted_config =
+      EncryptedConfig.find_or_initialize_by(account: current_account,
+                                            key: EncryptedConfig::TIMESTAMP_SERVER_URL_KEY)
+
+    @encrypted_config.assign_attributes(encrypted_config_params)
+  end
+
+  def encrypted_config_params
+    params.require(:encrypted_config).permit(:value)
+  end
+end

app/models/encrypted_config.rb

@@ -25,6 +25,7 @@ class EncryptedConfig < ApplicationRecord
     FILES_STORAGE_KEY = 'active_storage',
     EMAIL_SMTP_KEY = 'action_mailer_smtp',
     ESIGN_CERTS_KEY = 'esign_certs',
+    TIMESTAMP_SERVER_URL_KEY = 'timestamp_server_url',
     APP_URL_KEY = 'app_url',
     WEBHOOK_URL_KEY = 'webhook_url'
   ].freeze

app/views/esign_settings/show.html.erb

@@ -97,5 +97,31 @@
         </tbody>
       </table>
     </div>
+    <% encrypted_config = EncryptedConfig.find_or_initialize_by(account: current_account, key: EncryptedConfig::TIMESTAMP_SERVER_URL_KEY) %>
+    <% if !Docuseal.multitenant? && can?(:manage, encrypted_config) %>
+      <div class="flex-grow max-w-xl">
+        <div class="flex justify-between items-end mb-4 mt-8">
+          <h2 class="text-3xl font-bold">Timestamp Server</h2>
+        </div>
+        <%= form_for encrypted_config, url: timestamp_server_index_path, method: :post, html: { autocomplete: 'off', class: 'space-y-4' } do |f| %>
+          <div class="form-control">
+            <%= f.label :value, class: 'label' do %>
+              <span class="flex items-center space-x-1">
+                <span>
+                  Timeserver URL
+                </span>
+                <span class="tooltip" data-tip="URL of the trusted timeserver to be used to generate timestamp signatures.">
+                  <%= svg_icon('info_circle', class: 'w-4 h-4') %>
+                </span>
+              </span>
+            <% end %>
+            <%= f.url_field :value, autocomplete: 'off', class: 'base-input', placeholder: 'URL (optional)' %>
+          </div>
+          <div class="form-control pt-2">
+            <%= f.button button_title(title: 'Save', disabled_with: 'Updating'), class: 'base-button' %>
+          </div>
+        <% end %>
+      <% end %>
+    </div>
   </div>
 </div>

config/routes.rb

@@ -50,6 +50,7 @@ Rails.application.routes.draw do
   resources :verify_pdf_signature, only: %i[create]
   resource :mfa_setup, only: %i[show new edit create destroy], controller: 'mfa_setup'
   resources :account_configs, only: %i[create]
+  resources :timestamp_server, only: %i[create]
   resources :dashboard, only: %i[index]
   resources :setup, only: %i[index create]
   resource :newsletter, only: %i[show update]

lib/accounts.rb

@@ -71,6 +71,14 @@ module Accounts
     end
   end
 
+  def load_timeserver_url(account)
+    if Docuseal.multitenant?
+      Docuseal::TIMESERVER_URL
+    else
+      EncryptedConfig.find_by(account:, key: EncryptedConfig::TIMESTAMP_SERVER_URL_KEY)&.value
+    end.presence
+  end
+
   def can_send_emails?(_account)
     return true if Docuseal.multitenant?
     return true if ENV['SMTP_ADDRESS'].present?

lib/docuseal.rb

@@ -28,6 +28,7 @@ module Docuseal
             end
 
   CERTS = JSON.parse(ENV.fetch('CERTS', '{}'))
+  TIMESERVER_URL = ENV.fetch('TIMESERVER_URL', nil)
 
   DEFAULT_URL_OPTIONS = {
     host: HOST,

lib/submissions/generate_audit_trail.rb

@@ -32,6 +32,7 @@ module Submissions
     def call(submission)
       account = submission.template.account
       pkcs = Accounts.load_signing_pkcs(account)
+      tsa_url = Accounts.load_timeserver_url(account)
       verify_url = Rails.application.routes.url_helpers.settings_esign_url(**Docuseal.default_url_options)
 
       composer = HexaPDF::Composer.new(skip_page_creation: true)
@@ -254,10 +255,16 @@ module Submissions
 
       composer.document.trailer.info[:Creator] = INFO_CREATOR
 
-      composer.document.sign(io, reason: SIGN_REASON,
+      sign_params = {
-                                 certificate: pkcs.certificate,
+        reason: SIGN_REASON,
-                                 key: pkcs.key,
+        certificate: pkcs.certificate,
-                                 certificate_chain: pkcs.ca_certs || [])
+        key: pkcs.key,
+        certificate_chain: pkcs.ca_certs || []
+      }
+
+      sign_params[:timestamp_handler] = Submissions::TimestampHandler.new(tsa_url:) if tsa_url
+
+      composer.document.sign(io, **sign_params)
 
       ActiveStorage::Attachment.create!(
         blob: ActiveStorage::Blob.create_and_upload!(

lib/submissions/generate_result_attachments.rb

@@ -29,6 +29,7 @@ module Submissions
 
       account = submitter.submission.template.account
       pkcs = Accounts.load_signing_pkcs(account)
+      tsa_url = Accounts.load_timeserver_url(account)
 
       pdfs_index = build_pdfs_index(submitter)
 
@@ -190,7 +191,9 @@ module Submissions
         submitter.submission.template_schema.map do |item|
           pdf = pdfs_index[item['attachment_uuid']]
 
-          attachment = save_signed_pdf(pdf:, submitter:, pkcs:, uuid: item['attachment_uuid'], name: item['name'])
+          attachment = save_signed_pdf(pdf:, submitter:, pkcs:, tsa_url:,
+                                       uuid: item['attachment_uuid'],
+                                       name: item['name'])
 
           image_pdfs << pdf if original_documents.find { |a| a.uuid == item['attachment_uuid'] }.image?
 
@@ -217,15 +220,21 @@ module Submissions
     end
     # rubocop:enable Metrics
 
-    def save_signed_pdf(pdf:, submitter:, pkcs:, uuid:, name:)
+    def save_signed_pdf(pdf:, submitter:, pkcs:, tsa_url:, uuid:, name:)
       io = StringIO.new
 
       pdf.trailer.info[:Creator] = info_creator
 
-      pdf.sign(io, reason: sign_reason(submitter.email),
+      sign_params = {
-                   certificate: pkcs.certificate,
+        reason: sign_reason(submitter.email),
-                   key: pkcs.key,
+        certificate: pkcs.certificate,
-                   certificate_chain: pkcs.ca_certs || [])
+        key: pkcs.key,
+        certificate_chain: pkcs.ca_certs || []
+      }
+
+      sign_params[:timestamp_handler] = Submissions::TimestampHandler.new(tsa_url:) if tsa_url
+
+      pdf.sign(io, **sign_params)
 
       ActiveStorage::Attachment.create!(
         uuid:,

lib/submissions/timestamp_handler.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+module Submissions
+  class TimestampHandler
+    HASH_ALGORITHM = 'SHA512'
+
+    TimestampError = Class.new(StandardError)
+
+    attr_reader :tsa_url
+
+    def initialize(tsa_url:)
+      @tsa_url = tsa_url
+    end
+
+    def finalize_objects(_signature_field, signature)
+      signature.document.version = '2.0'
+
+      signature[:Type] = :DocTimeStamp
+      signature[:Filter] = :'Adobe.PPKLite'
+      signature[:SubFilter] = :'ETSI.RFC3161'
+    end
+
+    def sign(io, byte_range)
+      digest = OpenSSL::Digest.new(HASH_ALGORITHM)
+
+      io.pos = byte_range[0]
+      digest << io.read(byte_range[1])
+      io.pos = byte_range[2]
+      digest << io.read(byte_range[3])
+
+      uri = Addressable::URI.parse(tsa_url)
+
+      conn = Faraday.new(uri.origin) do |c|
+        c.basic_auth(uri.user, uri.password) if uri.password.present?
+      end
+
+      response = conn.post(uri.path, build_payload(digest.digest),
+                           'content-type' => 'application/timestamp-query')
+
+      raise TimestampError if response.status != 200 || response.body.blank?
+
+      OpenSSL::Timestamp::Response.new(response.body).token.to_der
+    end
+
+    def build_payload(digest)
+      req = OpenSSL::Timestamp::Request.new
+      req.algorithm = HASH_ALGORITHM
+      req.message_imprint = digest
+
+      req.to_der
+    end
+  end
+end