diff options
Diffstat (limited to 'actionpack/lib/action_dispatch/http/content_security_policy.rb')
| -rw-r--r-- | actionpack/lib/action_dispatch/http/content_security_policy.rb | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/actionpack/lib/action_dispatch/http/content_security_policy.rb b/actionpack/lib/action_dispatch/http/content_security_policy.rb new file mode 100644 index 0000000000..d10d4faf3d --- /dev/null +++ b/actionpack/lib/action_dispatch/http/content_security_policy.rb @@ -0,0 +1,233 @@ +# frozen_string_literal: true + +module ActionDispatch #:nodoc: + class ContentSecurityPolicy + class Middleware + CONTENT_TYPE = "Content-Type".freeze + POLICY = "Content-Security-Policy".freeze + POLICY_REPORT_ONLY = "Content-Security-Policy-Report-Only".freeze + + def initialize(app) + @app = app + end + + 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 + headers[header_name(request)] = policy.build(request.controller_instance) + end + + response + end + + private + + def html_response?(headers) + if content_type = headers[CONTENT_TYPE] + content_type =~ /html/ + end + end + + def header_name(request) + if request.content_security_policy_report_only + POLICY_REPORT_ONLY + else + POLICY + end + end + + def policy_present?(headers) + headers[POLICY] || headers[POLICY_REPORT_ONLY] + end + end + + module Request + POLICY = "action_dispatch.content_security_policy".freeze + POLICY_REPORT_ONLY = "action_dispatch.content_security_policy_report_only".freeze + + def content_security_policy + get_header(POLICY) + end + + def content_security_policy=(policy) + set_header(POLICY, policy) + end + + def content_security_policy_report_only + get_header(POLICY_REPORT_ONLY) + end + + def content_security_policy_report_only=(value) + set_header(POLICY_REPORT_ONLY, value) + end + end + + MAPPINGS = { + self: "'self'", + unsafe_eval: "'unsafe-eval'", + unsafe_inline: "'unsafe-inline'", + none: "'none'", + http: "http:", + https: "https:", + data: "data:", + mediastream: "mediastream:", + blob: "blob:", + filesystem: "filesystem:", + report_sample: "'report-sample'", + strict_dynamic: "'strict-dynamic'" + }.freeze + + DIRECTIVES = { + base_uri: "base-uri", + child_src: "child-src", + connect_src: "connect-src", + default_src: "default-src", + font_src: "font-src", + form_action: "form-action", + frame_ancestors: "frame-ancestors", + frame_src: "frame-src", + img_src: "img-src", + manifest_src: "manifest-src", + media_src: "media-src", + object_src: "object-src", + script_src: "script-src", + style_src: "style-src", + worker_src: "worker-src" + }.freeze + + private_constant :MAPPINGS, :DIRECTIVES + + attr_reader :directives + + def initialize + @directives = {} + yield self if block_given? + end + + def initialize_copy(other) + @directives = copy_directives(other.directives) + end + + DIRECTIVES.each do |name, directive| + define_method(name) do |*sources| + if sources.first + @directives[directive] = apply_mappings(sources) + else + @directives.delete(directive) + end + end + end + + def block_all_mixed_content(enabled = true) + if enabled + @directives["block-all-mixed-content"] = true + else + @directives.delete("block-all-mixed-content") + end + end + + def plugin_types(*types) + if types.first + @directives["plugin-types"] = types + else + @directives.delete("plugin-types") + end + end + + def report_uri(uri) + @directives["report-uri"] = [uri] + end + + def require_sri_for(*types) + if types.first + @directives["require-sri-for"] = types + else + @directives.delete("require-sri-for") + end + end + + def sandbox(*values) + if values.empty? + @directives["sandbox"] = true + elsif values.first + @directives["sandbox"] = values + else + @directives.delete("sandbox") + end + end + + def upgrade_insecure_requests(enabled = true) + if enabled + @directives["upgrade-insecure-requests"] = true + else + @directives.delete("upgrade-insecure-requests") + end + end + + def build(context = nil) + build_directives(context).compact.join("; ") + ";" + end + + private + def copy_directives(directives) + directives.transform_values { |sources| sources.map(&:dup) } + end + + def apply_mappings(sources) + sources.map do |source| + case source + when Symbol + apply_mapping(source) + when String, Proc + source + else + raise ArgumentError, "Invalid content security policy source: #{source.inspect}" + end + end + end + + def apply_mapping(source) + MAPPINGS.fetch(source) do + raise ArgumentError, "Unknown content security policy source mapping: #{source.inspect}" + end + end + + def build_directives(context) + @directives.map do |directive, sources| + if sources.is_a?(Array) + "#{directive} #{build_directive(sources, context).join(' ')}" + elsif sources + directive + else + nil + end + end + end + + def build_directive(sources, context) + sources.map { |source| resolve_source(source, context) } + end + + def resolve_source(source, context) + case source + when String + source + when Symbol + source.to_s + when Proc + if context.nil? + raise RuntimeError, "Missing context for the dynamic content security policy source: #{source.inspect}" + else + context.instance_exec(&source) + end + else + raise RuntimeError, "Unexpected content security policy source: #{source.inspect}" + end + end + end +end |