Add support for navigate-to, prefetch-src, and require-sri-for

Fixes github/secure_headers#387
Fixes github/secure_headers#388
Fixes github/secure_headers#264

lib/secure_headers/headers/content_security_policy.rb

@@ -51,14 +51,14 @@ def value
     def build_value
       directives.map do |directive_name|
         case DIRECTIVE_VALUE_TYPES[directive_name]
+        when :source_list, :require_sri_for_list # require_sri is a simple set of strings that don't need to deal with symbol casing
+          build_source_list_directive(directive_name)
         when :boolean
           symbol_to_hyphen_case(directive_name) if @config.directive_value(directive_name)
         when :sandbox_list
           build_sandbox_list_directive(directive_name)
         when :media_type_list
           build_media_type_list_directive(directive_name)
-        when :source_list
-          build_source_list_directive(directive_name)
         end
       end.compact.join("; ")
     end

lib/secure_headers/headers/content_security_policy_config.rb

@@ -27,11 +27,14 @@ def initialize(hash)
       @img_src = nil
       @manifest_src = nil
       @media_src = nil
+      @navigate_to = nil
       @object_src = nil
       @plugin_types = nil
+      @prefetch_src = nil
       @preserve_schemes = nil
       @report_only = nil
       @report_uri = nil
+      @require_sri_for = nil
       @sandbox = nil
       @script_nonce = nil
       @script_src = nil

lib/secure_headers/headers/policy_management.rb

@@ -1,4 +1,7 @@
 # frozen_string_literal: true
+
+require "set"
+
 module SecureHeaders
   module PolicyManagement
     def self.included(base)
@@ -70,13 +73,19 @@ def self.included(base)
     # https://w3c.github.io/webappsec/specs/CSP2/
     BLOCK_ALL_MIXED_CONTENT = :block_all_mixed_content
     MANIFEST_SRC = :manifest_src
+    NAVIGATE_TO = :navigate_to
+    PREFETCH_SRC = :prefetch_src
+    REQUIRE_SRI_FOR = :require_sri_for
     UPGRADE_INSECURE_REQUESTS = :upgrade_insecure_requests
     WORKER_SRC = :worker_src
 
     DIRECTIVES_3_0 = [
       DIRECTIVES_2_0,
       BLOCK_ALL_MIXED_CONTENT,
       MANIFEST_SRC,
+      NAVIGATE_TO,
+      PREFETCH_SRC,
+      REQUIRE_SRI_FOR,
       WORKER_SRC,
       UPGRADE_INSECURE_REQUESTS
     ].flatten.freeze
@@ -100,14 +109,17 @@ def self.included(base)
       IMG_SRC                   => :source_list,
       MANIFEST_SRC              => :source_list,
       MEDIA_SRC                 => :source_list,
+      NAVIGATE_TO               => :source_list,
       OBJECT_SRC                => :source_list,
       PLUGIN_TYPES              => :media_type_list,
+      REQUIRE_SRI_FOR           => :require_sri_for_list,
       REPORT_URI                => :source_list,
+      PREFETCH_SRC              => :source_list,
       SANDBOX                   => :sandbox_list,
       SCRIPT_SRC                => :source_list,
       STYLE_SRC                 => :source_list,
       WORKER_SRC                => :source_list,
-      UPGRADE_INSECURE_REQUESTS => :boolean
+      UPGRADE_INSECURE_REQUESTS => :boolean,
     }.freeze
 
     # These are directives that don't have use a source list, and hence do not
@@ -122,7 +134,8 @@ def self.included(base)
       BASE_URI,
       FORM_ACTION,
       FRAME_ANCESTORS,
-      REPORT_URI
+      NAVIGATE_TO,
+      REPORT_URI,
     ]
 
     FETCH_SOURCES = ALL_DIRECTIVES - NON_FETCH_SOURCES - NON_SOURCE_LIST_SOURCES
@@ -148,6 +161,8 @@ def self.included(base)
       :style_nonce
     ].freeze
 
+    REQUIRE_SRI_FOR_VALUES = Set.new(%w(script style))
+
     module ClassMethods
       # Public: generate a header name, value array that is user-agent-aware.
       #
@@ -241,7 +256,8 @@ def merge_policy_additions(original, additions)
       def list_directive?(directive)
         source_list?(directive) ||
           sandbox_list?(directive) ||
-          media_type_list?(directive)
+          media_type_list?(directive) ||
+          require_sri_for_list?(directive)
       end
 
       # For each directive in additions that does not exist in the original config,
@@ -274,11 +290,17 @@ def media_type_list?(directive)
         DIRECTIVE_VALUE_TYPES[directive] == :media_type_list
       end
 
+      def require_sri_for_list?(directive)
+        DIRECTIVE_VALUE_TYPES[directive] == :require_sri_for_list
+      end
+
       # Private: Validates that the configuration has a valid type, or that it is a valid
       # source expression.
       def validate_directive!(directive, value)
         ensure_valid_directive!(directive)
         case ContentSecurityPolicy::DIRECTIVE_VALUE_TYPES[directive]
+        when :source_list
+          validate_source_expression!(directive, value)
         when :boolean
           unless boolean?(value)
             raise ContentSecurityPolicyConfigError.new("#{directive} must be a boolean. Found #{value.class} value")
@@ -287,8 +309,8 @@ def validate_directive!(directive, value)
           validate_sandbox_expression!(directive, value)
         when :media_type_list
           validate_media_type_expression!(directive, value)
-        when :source_list
-          validate_source_expression!(directive, value)
+        when :require_sri_for_list
+          validate_require_sri_source_expression!(directive, value)
         else
           raise ContentSecurityPolicyConfigError.new("Unknown directive #{directive}")
         end
@@ -323,6 +345,16 @@ def validate_media_type_expression!(directive, media_type_expression)
         end
       end
 
+      # Private: validates that a require sri for expression:
+      # 1. is an array of strings
+      # 2. is a subset of ["string", "style"]
+      def validate_require_sri_source_expression!(directive, require_sri_for_expression)
+        ensure_array_of_strings!(directive, require_sri_for_expression)
+        unless require_sri_for_expression.to_set.subset?(REQUIRE_SRI_FOR_VALUES)
+          raise ContentSecurityPolicyConfigError.new(%(require-sri for must be a subset of #{REQUIRE_SRI_FOR_VALUES.to_a} but was #{require_sri_for_expression}))
+        end
+      end
+
       # Private: validates that a source expression:
       # 1. is an array of strings
       # 2. does not contain any deprecated, now invalid values (inline, eval, self, none)

spec/lib/secure_headers/headers/content_security_policy_spec.rb

@@ -116,6 +116,31 @@ module SecureHeaders
         ContentSecurityPolicy.new(default_src: %w('self'), frame_src: %w('self')).value
       end
 
+      it "allows script as a require-sri-src" do
+        csp = ContentSecurityPolicy.new(default_src: %w('self'), require_sri_for: %w(script))
+        expect(csp.value).to eq("default-src 'self'; require-sri-for script")
+      end
+
+      it "allows style as a require-sri-src" do
+        csp = ContentSecurityPolicy.new(default_src: %w('self'), require_sri_for: %w(style))
+        expect(csp.value).to eq("default-src 'self'; require-sri-for style")
+      end
+
+      it "allows script and style as a require-sri-src" do
+        csp = ContentSecurityPolicy.new(default_src: %w('self'), require_sri_for: %w(script style))
+        expect(csp.value).to eq("default-src 'self'; require-sri-for script style")
+      end
+
+      it "includes prefetch-src" do
+        csp = ContentSecurityPolicy.new(default_src: %w('self'), prefetch_src: %w(foo.com))
+        expect(csp.value).to eq("default-src 'self'; prefetch-src foo.com")
+      end
+
+      it "includes navigate-to" do
+        csp = ContentSecurityPolicy.new(default_src: %w('self'), navigate_to: %w(foo.com))
+        expect(csp.value).to eq("default-src 'self'; navigate-to foo.com")
+      end
+
       it "supports strict-dynamic" do
         csp = ContentSecurityPolicy.new({default_src: %w('self'), script_src: [ContentSecurityPolicy::STRICT_DYNAMIC], script_nonce: 123456})
         expect(csp.value).to eq("default-src 'self'; script-src 'strict-dynamic' 'nonce-123456' 'unsafe-inline'")

spec/lib/secure_headers/headers/policy_management_spec.rb

@@ -28,24 +28,29 @@ module SecureHeaders
 
           # directive values: these values will directly translate into source directives
           default_src: %w(https: 'self'),
-          frame_src: %w('self' *.twimg.com itunes.apple.com),
-          child_src: %w('self' *.twimg.com itunes.apple.com),
+
+          base_uri: %w('self'),
+          block_all_mixed_content: true, # see [http://www.w3.org/TR/mixed-content/](http://www.w3.org/TR/mixed-content/)
           connect_src: %w(wss:),
+          child_src: %w('self' *.twimg.com itunes.apple.com),
           font_src: %w('self' data:),
+          form_action: %w('self' github.com),
+          frame_ancestors: %w('none'),
+          frame_src: %w('self' *.twimg.com itunes.apple.com),
           img_src: %w(mycdn.com data:),
           manifest_src: %w(manifest.com),
           media_src: %w(utoob.com),
+          navigate_to: %w(netscape.com),
           object_src: %w('self'),
+          plugin_types: %w(application/x-shockwave-flash),
+          prefetch_src: %w(fetch.com),
+          require_sri_for: %w(script style),
           script_src: %w('self'),
           style_src: %w('unsafe-inline'),
-          worker_src: %w(worker.com),
-          base_uri: %w('self'),
-          form_action: %w('self' github.com),
-          frame_ancestors: %w('none'),
-          plugin_types: %w(application/x-shockwave-flash),
-          block_all_mixed_content: true, # see [http://www.w3.org/TR/mixed-content/](http://www.w3.org/TR/mixed-content/)
           upgrade_insecure_requests: true, # see https://www.w3.org/TR/upgrade-insecure-requests/
-          report_uri: %w(https://example.com/uri-directive)
+          worker_src: %w(worker.com),
+
+          report_uri: %w(https://example.com/uri-directive),
         }
 
         ContentSecurityPolicy.validate_config!(ContentSecurityPolicyConfig.new(config))