Allow adding/removing of existing Content-Security-Policy and `Perm…

…issions-Policy` directives.

Previously, if you wanted to add/remove directives from either header, you had to redefine the defaults in the controller.

Now, you can adjust the policy directives without overwriting the global configuration.

actionpack/CHANGELOG.md

@@ -1,3 +1,11 @@
+*   Allow adding/removing of existing `Content-Security-Policy` and `Permissions-Policy` directives.
+
+    Previously, if you wanted to add/remove directives from either header, you had to redefine the defaults in the controller.
+
+    Now, you can adjust the policy directives without overwriting the global configuration.
+
+    *Alex Robbin*
+
 *   Include source location in routes extended view.
 
     ```bash

actionpack/lib/action_dispatch/http/content_security_policy.rb

@@ -190,6 +190,20 @@ def initialize_copy(other)
           @directives.delete(directive)
         end
       end
+
+      define_method("add_#{name}") do |*sources|
+        existing_sources = @directives.fetch(directive, [])
+
+        public_send(name, *(existing_sources + sources).uniq)
+      end
+
+      define_method("remove_#{name}") do |*sources|
+        existing_sources = @directives.fetch(directive, [])
+
+        sources.each { |source| existing_sources.delete(source) }
+
+        public_send(name, *(existing_sources - apply_mappings(sources)))
+      end
     end
 
     # Specify whether to prevent the user agent from loading any assets over

actionpack/lib/action_dispatch/http/permissions_policy.rb

@@ -133,6 +133,18 @@ def initialize_copy(other)
           @directives.delete(directive)
         end
       end
+
+      define_method("add_#{name}") do |*sources|
+        existing_sources = @directives.fetch(directive, [])
+
+        public_send(name, *(existing_sources + sources).uniq)
+      end
+
+      define_method("remove_#{name}") do |*sources|
+        existing_sources = @directives.fetch(directive, [])
+
+        public_send(name, *(existing_sources - apply_mappings(sources)))
+      end
     end
 
     %w[speaker vibrate vr].each do |directive|

actionpack/test/dispatch/content_security_policy_test.rb

@@ -247,6 +247,18 @@ def test_multiple_directives
     assert_equal "script-src 'self' https:; style-src 'self' https:", @policy.build
   end
 
+  def test_add_directives
+    @policy.script_src :self
+    @policy.add_script_src :https
+    assert_equal "script-src 'self' https:", @policy.build
+  end
+
+  def test_remove_directives
+    @policy.script_src :self, :https
+    @policy.remove_script_src :https
+    assert_equal "script-src 'self'", @policy.build
+  end
+
   def test_dynamic_directives
     request = ActionDispatch::Request.new("HTTP_HOST" => "www.example.com")
     controller = Struct.new(:request).new(request)

actionpack/test/dispatch/permissions_policy_test.rb

@@ -32,6 +32,18 @@ def test_multiple_directives_for_multiple_directives
     assert_equal "geolocation 'self' https://example.com; usb 'none' https://example.com", @policy.build
   end
 
+  def test_add_directives
+    @policy.geolocation :self
+    @policy.add_geolocation "https://example.com"
+    assert_equal "geolocation 'self' https://example.com", @policy.build
+  end
+
+  def test_remove_directives
+    @policy.geolocation :self, "https://example.com"
+    @policy.remove_geolocation "https://example.com"
+    assert_equal "geolocation 'self'", @policy.build
+  end
+
   def test_invalid_directive_source
     exception = assert_raises(ArgumentError) do
       @policy.geolocation [:non_existent]

railties/test/application/content_security_policy_test.rb

@@ -182,6 +182,70 @@ def index
       assert_policy "default-src https://example.com"
     end
 
+    test "add directives to content security policy in a controller" do
+      controller :pages, <<-RUBY
+        class PagesController < ApplicationController
+          content_security_policy do |p|
+            p.add_script_src "https://example.com"
+          end
+
+          def index
+            render html: "<h1>Welcome to Rails!</h1>"
+          end
+        end
+      RUBY
+
+      app_file "config/initializers/content_security_policy.rb", <<-RUBY
+        Rails.application.config.content_security_policy do |p|
+          p.default_src :self, :https
+          p.script_src :self
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          root to: "pages#index"
+        end
+      RUBY
+
+      app("development")
+
+      get "/"
+      assert_policy "default-src 'self' https:; script-src 'self' https://example.com"
+    end
+
+    test "remove directives to content security policy in a controller" do
+      controller :pages, <<-RUBY
+        class PagesController < ApplicationController
+          content_security_policy do |p|
+            p.remove_script_src "https://example.com"
+          end
+
+          def index
+            render html: "<h1>Welcome to Rails!</h1>"
+          end
+        end
+      RUBY
+
+      app_file "config/initializers/content_security_policy.rb", <<-RUBY
+        Rails.application.config.content_security_policy do |p|
+          p.default_src :self, :https
+          p.script_src 'https://example.com'
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          root to: "pages#index"
+        end
+      RUBY
+
+      app("development")
+
+      get "/"
+      assert_policy "default-src 'self' https:"
+    end
+
     test "override content security policy to report only in a controller" do
       controller :pages, <<-RUBY
         class PagesController < ApplicationController

railties/test/application/permissions_policy_test.rb

@@ -95,6 +95,68 @@ def index
       assert_policy "geolocation https://example.com"
     end
 
+    test "add directive to permissions policy in a controller" do
+      controller :pages, <<-RUBY
+        class PagesController < ApplicationController
+          permissions_policy do |p|
+            p.add_geolocation "https://example.com"
+          end
+
+          def index
+            render html: "<h1>Welcome to Rails!</h1>"
+          end
+        end
+      RUBY
+
+      app_file "config/initializers/permissions_policy.rb", <<-RUBY
+        Rails.application.config.permissions_policy do |p|
+          p.geolocation :self
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          root to: "pages#index"
+        end
+      RUBY
+
+      app("development")
+
+      get "/"
+      assert_policy "geolocation 'self' https://example.com"
+    end
+
+    test "remove directive from permissions policy in a controller" do
+      controller :pages, <<-RUBY
+        class PagesController < ApplicationController
+          permissions_policy do |p|
+            p.remove_geolocation "https://example.com"
+          end
+
+          def index
+            render html: "<h1>Welcome to Rails!</h1>"
+          end
+        end
+      RUBY
+
+      app_file "config/initializers/permissions_policy.rb", <<-RUBY
+        Rails.application.config.permissions_policy do |p|
+          p.geolocation :self, "https://example.com"
+        end
+      RUBY
+
+      app_file "config/routes.rb", <<-RUBY
+        Rails.application.routes.draw do
+          root to: "pages#index"
+        end
+      RUBY
+
+      app("development")
+
+      get "/"
+      assert_policy "geolocation 'self'"
+    end
+
     test "override permissions policy by unsetting a directive in a controller" do
       controller :pages, <<-RUBY
         class PagesController < ApplicationController