Security: Enable Content Security Policy

config/initializers/content_security_policy.rb

@@ -5,23 +5,29 @@
 # For further information see the following documentation
 # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
 
-# Rails.application.configure do
-#   config.content_security_policy do |policy|
-#     policy.default_src :self, :https
-#     policy.font_src    :self, :https, :data
-#     policy.img_src     :self, :https, :data
-#     policy.object_src  :none
-#     policy.script_src  :self, :https
-#     policy.style_src   :self, :https
-#     # Specify URI for violation reports
-#     # policy.report_uri "/csp-violation-report-endpoint"
-#   end
-#
-#   # Generate session nonces for permitted importmap and inline scripts
-#   config.content_security_policy_nonce_generator = ->(request) { request.session.id.to_s }
-#   config.content_security_policy_nonce_directives = %w(script-src)
-#
-#   # Report CSP violations to a specified URI. See:
-#   # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy-Report-Only
-#   # config.content_security_policy_report_only = true
-# end
+Rails.application.configure do
+  config.content_security_policy do |policy|
+    policy.default_src :self
+    policy.font_src    :self, "https://fonts.gstatic.com", :data
+    policy.img_src     :self, :https, :data, :blob
+    policy.object_src  :none
+    policy.script_src  :self, :strict_dynamic
+    policy.style_src   :self, "https://fonts.googleapis.com", :unsafe_inline
+    policy.connect_src :self, :https
+    policy.frame_src   :self, "https://tally.so"
+    policy.base_uri    :self
+    policy.form_action :self
+
+    # Specify URI for violation reports
+    # policy.report_uri "/csp-violation-report-endpoint"
+  end
+
+  # Generate session nonces for permitted importmap and inline scripts
+  # Required for Turbo/Stimulus and importmap-rails
+  config.content_security_policy_nonce_generator = ->(request) { request.session.id.to_s }
+  config.content_security_policy_nonce_directives = %w[script-src]
+
+  # Report CSP violations to a specified URI. See:
+  # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy-Report-Only
+  # config.content_security_policy_report_only = true
+end