DEV: Remove unsafe-eval from development CSP (#8569)

- Refactor source_url to avoid using eval in development
- Precompile handlebars in development
- Include template compilers when running qunit
- Remove unsafe-eval in development CSP
- Include unsafe-eval only for qunit routes in development

app/assets/javascripts/template_include.js

@@ -0,0 +1 @@
+//= require handlebars.runtime

app/assets/javascripts/template_include.js.erb

@@ -1,8 +0,0 @@
-<%
-if Rails.env.development? || Rails.env.test?
-  require_asset ("handlebars.js")
-  require_asset ("ember-template-compiler.js")
-else
-  require_asset ("handlebars.runtime.js")
-end
-%>

config/environments/development.rb

@@ -30,7 +30,7 @@ Discourse::Application.configure do
   config.active_record.migration_error = :page_load
   config.watchable_dirs['lib'] = [:rb]
 
-  config.handlebars.precompile = false
+  config.handlebars.precompile = true
 
   # we recommend you use mailcatcher https://github.com/sj26/mailcatcher
   config.action_mailer.smtp_settings = { address: "localhost", port: 1025 }

config/initializers/010-discourse_iife.rb

@@ -5,7 +5,7 @@ require 'discourse_iife'
 Rails.application.config.assets.configure do |env|
   env.register_preprocessor('application/javascript', DiscourseIIFE)
 
-  unless Rails.env.production? || ENV["DISABLE_EVAL"]
+  unless Rails.env.production?
     require 'source_url'
     env.register_postprocessor('application/javascript', SourceURL)
   end

lib/content_security_policy.rb

@@ -4,8 +4,8 @@ require 'content_security_policy/extension'
 
 class ContentSecurityPolicy
   class << self
-    def policy(theme_ids = [])
-      new.build(theme_ids)
+    def policy(theme_ids = [], path_info: "/")
+      new.build(theme_ids, path_info: path_info)
     end
 
     def base_url
@@ -14,12 +14,13 @@ class ContentSecurityPolicy
     attr_writer :base_url
   end
 
-  def build(theme_ids)
+  def build(theme_ids, path_info: "/")
     builder = Builder.new
 
     Extension.theme_extensions(theme_ids).each { |extension| builder << extension }
     Extension.plugin_extensions.each { |extension| builder << extension }
     builder << Extension.site_setting_extension
+    builder << Extension.path_specific_extension(path_info)
 
     builder.build
   end

lib/content_security_policy/default.rb

@@ -51,7 +51,6 @@ class ContentSecurityPolicy
         "#{base_url}/mini-profiler-resources/",
         *script_assets
       ].tap do |sources|
-        sources << :unsafe_eval if Rails.env.development? # TODO Remove this when we stop using `eval` in development mode
         sources << 'https://www.google-analytics.com/analytics.js' if SiteSetting.ga_universal_tracking_code.present?
         sources << 'https://www.googletagmanager.com/gtm.js' if SiteSetting.gtm_container_id.present?
       end

lib/content_security_policy/extension.rb

@@ -7,6 +7,13 @@ class ContentSecurityPolicy
       { script_src: SiteSetting.content_security_policy_script_src.split('|') }
     end
 
+    def path_specific_extension(path_info)
+      {}.tap do |obj|
+        for_qunit_route = !Rails.env.production? && ["/qunit", "/wizard/qunit"].include?(path_info)
+        obj[:script_src] = :unsafe_eval if for_qunit_route
+      end
+    end
+
     def plugin_extensions
       [].tap do |extensions|
         Discourse.plugins.each do |plugin|

lib/content_security_policy/middleware.rb

@@ -15,8 +15,9 @@ class ContentSecurityPolicy
       ContentSecurityPolicy.base_url = request.host_with_port if Rails.env.development?
 
       theme_ids = env[:resolved_theme_ids]
-      headers['Content-Security-Policy'] = policy(theme_ids) if SiteSetting.content_security_policy
-      headers['Content-Security-Policy-Report-Only'] = policy(theme_ids) if SiteSetting.content_security_policy_report_only
+
+      headers['Content-Security-Policy'] = policy(theme_ids, path_info: env["PATH_INFO"]) if SiteSetting.content_security_policy
+      headers['Content-Security-Policy-Report-Only'] = policy(theme_ids, path_info: env["PATH_INFO"]) if SiteSetting.content_security_policy_report_only
 
       response
     end

lib/source_url.rb

@@ -16,10 +16,9 @@ class SourceURL < Tilt::Template
   end
 
   def evaluate(scope, locals, &block)
-    code = +"eval("
-    code << data.inspect
-    code << " + \"\\n//# sourceURL=#{scope.logical_path}\""
-    code << ");\n"
+    code = +"\n//# BEGIN sourceURL=#{scope.logical_path}\n"
+    code << data
+    code << "\n//# END sourceURL=#{scope.logical_path}\n"
     code
   end
 end

spec/lib/content_security_policy_spec.rb

@@ -123,6 +123,12 @@ describe ContentSecurityPolicy do
     Discourse.plugins.pop
   end
 
+  it 'only includes unsafe-inline for qunit paths' do
+    expect(parse(policy(path_info: "/qunit"))['script-src']).to include("'unsafe-eval'")
+    expect(parse(policy(path_info: "/wizard/qunit"))['script-src']).to include("'unsafe-eval'")
+    expect(parse(policy(path_info: "/"))['script-src']).to_not include("'unsafe-eval'")
+  end
+
   context "with a theme" do
     let!(:theme) {
       Fabricate(:theme).tap do |t|
@@ -174,7 +180,7 @@ describe ContentSecurityPolicy do
     end.to_h
   end
 
-  def policy(theme_ids = [])
-    ContentSecurityPolicy.policy(theme_ids)
+  def policy(theme_ids = [], path_info: "/")
+    ContentSecurityPolicy.policy(theme_ids, path_info: path_info)
   end
 end

test/javascripts/test_helper.js

@@ -3,9 +3,7 @@
 //= require env
 //= require jquery.debug
 //= require jquery.ui.widget
-//= require handlebars
 //= require ember.debug
-//= require ember-template-compiler
 //= require message-bus
 //= require qunit/qunit/qunit
 //= require ember-qunit
@@ -26,6 +24,11 @@
 //= require application
 //= require admin
 
+// These are not loaded in prod or development
+// But we need them for testing handlebars templates in qunit
+//= require handlebars
+//= require ember-template-compiler
+
 //= require sinon/pkg/sinon
 
 //= require helpers/assertions