Merge pull request #486 from github/kyfast-add-trusted-types

Add trusted-types and require-trusted-types-for CSP Directive

Author: KyFaSt

lib/secure_headers/headers/content_security_policy.rb

@@ -53,7 +53,9 @@ 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
+        when :source_list,
+             :require_sri_for_list, # require_sri is a simple set of strings that don't need to deal with symbol casing
+             :require_trusted_types_for_list
           build_source_list_directive(directive_name)
         when :boolean
           symbol_to_hyphen_case(directive_name) if @config.directive_value(directive_name)

lib/secure_headers/headers/content_security_policy_config.rb

@@ -35,6 +35,7 @@ def initialize(hash)
       @report_only = nil
       @report_uri = nil
       @require_sri_for = nil
+      @require_trusted_types_for = nil
       @sandbox = nil
       @script_nonce = nil
       @script_src = nil
@@ -44,6 +45,7 @@ def initialize(hash)
       @style_src = nil
       @style_src_elem = nil
       @style_src_attr = nil
+      @trusted_types = nil
       @worker_src = nil
       @upgrade_insecure_requests = nil
       @disable_nonce_backwards_compatibility = nil

lib/secure_headers/headers/policy_management.rb

@@ -98,7 +98,19 @@ def self.included(base)
       STYLE_SRC_ATTR
     ].flatten.freeze
 
-    ALL_DIRECTIVES = (DIRECTIVES_1_0 + DIRECTIVES_2_0 + DIRECTIVES_3_0).uniq.sort
+    # Experimental directives - these vary greatly in support
+    # See MDN for details.
+    # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/trusted-types
+    TRUSTED_TYPES = :trusted_types
+    # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/require-trusted-types-for
+    REQUIRE_TRUSTED_TYPES_FOR = :require_trusted_types_for
+
+    DIRECTIVES_EXPERIMENTAL = [
+      TRUSTED_TYPES,
+      REQUIRE_TRUSTED_TYPES_FOR,
+    ].flatten.freeze
+
+    ALL_DIRECTIVES = (DIRECTIVES_1_0 + DIRECTIVES_2_0 + DIRECTIVES_3_0 + DIRECTIVES_EXPERIMENTAL).uniq.sort
 
     # Think of default-src and report-uri as the beginning and end respectively,
     # everything else is in between.
@@ -121,6 +133,7 @@ def self.included(base)
       OBJECT_SRC                => :source_list,
       PLUGIN_TYPES              => :media_type_list,
       REQUIRE_SRI_FOR           => :require_sri_for_list,
+      REQUIRE_TRUSTED_TYPES_FOR => :require_trusted_types_for_list,
       REPORT_URI                => :source_list,
       PREFETCH_SRC              => :source_list,
       SANDBOX                   => :sandbox_list,
@@ -130,6 +143,7 @@ def self.included(base)
       STYLE_SRC                 => :source_list,
       STYLE_SRC_ELEM            => :source_list,
       STYLE_SRC_ATTR            => :source_list,
+      TRUSTED_TYPES             => :source_list,
       WORKER_SRC                => :source_list,
       UPGRADE_INSECURE_REQUESTS => :boolean,
     }.freeze
@@ -175,6 +189,7 @@ def self.included(base)
     ].freeze
 
     REQUIRE_SRI_FOR_VALUES = Set.new(%w(script style))
+    REQUIRE_TRUSTED_TYPES_FOR_VALUES = Set.new(%w(script))
 
     module ClassMethods
       # Public: generate a header name, value array that is user-agent-aware.
@@ -270,7 +285,8 @@ def list_directive?(directive)
         source_list?(directive) ||
           sandbox_list?(directive) ||
           media_type_list?(directive) ||
-          require_sri_for_list?(directive)
+          require_sri_for_list?(directive) ||
+          require_trusted_types_for_list?(directive)
       end
 
       # For each directive in additions that does not exist in the original config,
@@ -308,6 +324,10 @@ def require_sri_for_list?(directive)
         DIRECTIVE_VALUE_TYPES[directive] == :require_sri_for_list
       end
 
+      def require_trusted_types_for_list?(directive)
+        DIRECTIVE_VALUE_TYPES[directive] == :require_trusted_types_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)
@@ -325,6 +345,8 @@ def validate_directive!(directive, value)
           validate_media_type_expression!(directive, value)
         when :require_sri_for_list
           validate_require_sri_source_expression!(directive, value)
+        when :require_trusted_types_for_list
+          validate_require_trusted_types_for_source_expression!(directive, value)
         else
           raise ContentSecurityPolicyConfigError.new("Unknown directive #{directive}")
         end
@@ -369,6 +391,16 @@ def validate_require_sri_source_expression!(directive, require_sri_for_expressio
         end
       end
 
+      # Private: validates that a require trusted types for expression:
+      # 1. is an array of strings
+      # 2. is a subset of ["script"]
+      def validate_require_trusted_types_for_source_expression!(directive, require_trusted_types_for_expression)
+        ensure_array_of_strings!(directive, require_trusted_types_for_expression)
+        unless require_trusted_types_for_expression.to_set.subset?(REQUIRE_TRUSTED_TYPES_FOR_VALUES)
+          raise ContentSecurityPolicyConfigError.new(%(require-trusted-types-for for must be a subset of #{REQUIRE_TRUSTED_TYPES_FOR_VALUES.to_a} but was #{require_trusted_types_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

@@ -146,6 +146,11 @@ module SecureHeaders
         expect(csp.value).to eq("default-src 'self'; require-sri-for script style")
       end
 
+      it "allows style as a require-trusted-types-for source" do
+        csp = ContentSecurityPolicy.new(default_src: %w('self'), require_trusted_types_for: %w(script))
+        expect(csp.value).to eq("default-src 'self'; require-trusted-types-for script")
+      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")
@@ -185,6 +190,21 @@ module SecureHeaders
         csp = ContentSecurityPolicy.new({style_src: %w('self'), style_src_attr: %w('self')})
         expect(csp.value).to eq("style-src 'self'; style-src-attr 'self'")
       end
+
+      it "supports trusted-types directive" do
+        csp = ContentSecurityPolicy.new({trusted_types: %w(blahblahpolicy)})
+        expect(csp.value).to eq("trusted-types blahblahpolicy")
+      end
+
+      it "supports trusted-types directive with 'none'" do
+        csp = ContentSecurityPolicy.new({trusted_types: %w(none)})
+        expect(csp.value).to eq("trusted-types none")
+      end
+
+      it "allows duplicate policy names in trusted-types directive" do
+        csp = ContentSecurityPolicy.new({trusted_types: %w(blahblahpolicy 'allow-duplicates')})
+        expect(csp.value).to eq("trusted-types blahblahpolicy 'allow-duplicates'")
+      end
     end
   end
 end

spec/lib/secure_headers/headers/policy_management_spec.rb

@@ -45,6 +45,7 @@ module SecureHeaders
           plugin_types: %w(application/x-shockwave-flash),
           prefetch_src: %w(fetch.com),
           require_sri_for: %w(script style),
+          require_trusted_types_for: %w(script),
           script_src: %w('self'),
           style_src: %w('unsafe-inline'),
           upgrade_insecure_requests: true, # see https://www.w3.org/TR/upgrade-insecure-requests/
@@ -53,6 +54,7 @@ module SecureHeaders
           script_src_attr: %w(example.com),
           style_src_elem: %w(example.com),
           style_src_attr: %w(example.com),
+          trusted_types: %w(abcpolicy),
 
           report_uri: %w(https://example.com/uri-directive),
         }
@@ -120,6 +122,12 @@ module SecureHeaders
         end.to raise_error(ContentSecurityPolicyConfigError)
       end
 
+      it "rejects style for trusted types" do
+        expect do
+          ContentSecurityPolicy.validate_config!(ContentSecurityPolicyConfig.new(default_opts.merge(style_src: %w('self'), require_trusted_types_for: %w(script style), trusted_types: %w(abcpolicy))))
+        end
+      end
+
       # this is mostly to ensure people don't use the antiquated shorthands common in other configs
       it "performs light validation on source lists" do
         expect do