Generate content security policy for non-HTML responses

actionpack/CHANGELOG.md

@@ -1,3 +1,6 @@
+*   Allow Content Security Policy DSL to generate for API responses.
+    *Tim Wade*
+
 *   Fix `authenticate_with_http_basic` to allow for missing password.
 
     Before Rails 7.0 it was possible to handle basic authentication with only a username.

actionpack/lib/action_dispatch/http/content_security_policy.rb

@@ -35,7 +35,6 @@ def call(env)
         request = ActionDispatch::Request.new env
         _, headers, _ = response = @app.call(env)
 
-        return response unless html_response?(headers)
         return response if policy_present?(headers)
 
         if policy = request.content_security_policy
@@ -49,12 +48,6 @@ def call(env)
       end
 
       private
-        def html_response?(headers)
-          if content_type = headers[CONTENT_TYPE]
-            /html/.match?(content_type)
-          end
-        end
-
         def header_name(request)
           if request.content_security_policy_report_only
             POLICY_REPORT_ONLY

actionpack/test/dispatch/content_security_policy_test.rb

@@ -403,6 +403,11 @@ class PolicyController < ActionController::Base
 
     content_security_policy_report_only only: :report_only
 
+    content_security_policy only: :api do |p|
+      p.default_src :none
+      p.frame_ancestors :none
+    end
+
     def index
       head :ok
     end
@@ -431,6 +436,10 @@ def no_policy
       head :ok
     end
 
+    def api
+      render json: {}
+    end
+
     private
       def condition?
         params[:condition] == "true"
@@ -447,6 +456,7 @@ def condition?
       get "/script-src", to: "policy#script_src"
       get "/style-src", to: "policy#style_src"
       get "/no-policy", to: "policy#no_policy"
+      get "/api", to: "policy#api"
     end
   end
 
@@ -518,6 +528,11 @@ def test_generates_no_content_security_policy
     assert_nil response.headers["Content-Security-Policy-Report-Only"]
   end
 
+  def test_generates_api_security_policy
+    get "/api"
+    assert_policy "default-src 'none'; frame-ancestors 'none'"
+  end
+
   private
     def assert_policy(expected, report_only: false)
       assert_response :success