Encode Content-Disposition filenames on send_data and send_file

2 files changed, 48 insertions, 4 deletions

diff --git a/actionpack/lib/action_controller/metal/data_streaming.rb b/actionpack/lib/action_controller/metal/data_streaming.rb
index 5a82ccf668..5140a667de 100644
--- a/actionpack/lib/action_controller/metal/data_streaming.rb
+++ b/actionpack/lib/action_controller/metal/data_streaming.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "action_controller/metal/exceptions"
+require "action_dispatch/http/content_disposition"
 
 module ActionController #:nodoc:
   # Methods for sending arbitrary data and for streaming files to the browser,
@@ -132,10 +133,8 @@ module ActionController #:nodoc:
         end
 
         disposition = options.fetch(:disposition, DEFAULT_SEND_FILE_DISPOSITION)
-        unless disposition.nil?
-          disposition  = disposition.to_s
-          disposition += %(; filename="#{options[:filename]}") if options[:filename]
-          headers["Content-Disposition"] = disposition
+        if disposition
+          headers["Content-Disposition"] = ActionDispatch::Http::ContentDisposition.format(disposition: disposition, filename: options[:filename])
         end
 
         headers["Content-Transfer-Encoding"] = "binary"
diff --git a/actionpack/lib/action_dispatch/http/content_disposition.rb b/actionpack/lib/action_dispatch/http/content_disposition.rb
new file mode 100644
index 0000000000..58164c1522
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/content_disposition.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module ActionDispatch
+  module Http
+    class ContentDisposition # :nodoc:
+      def self.format(disposition:, filename:)
+        new(disposition: disposition, filename: filename).to_s
+      end
+
+      attr_reader :disposition, :filename
+
+      def initialize(disposition:, filename:)
+        @disposition = disposition
+        @filename = filename
+      end
+
+      TRADITIONAL_ESCAPED_CHAR = /[^ A-Za-z0-9!#$+.^_`|~-]/
+
+      def ascii_filename
+        'filename="' + percent_escape(I18n.transliterate(filename), TRADITIONAL_ESCAPED_CHAR) + '"'
+      end
+
+      RFC_5987_ESCAPED_CHAR = /[^A-Za-z0-9!#$&+.^_`|~-]/
+
+      def utf8_filename
+        "filename*=UTF-8''" + percent_escape(filename, RFC_5987_ESCAPED_CHAR)
+      end
+
+      def to_s
+        if filename
+          "#{disposition}; #{ascii_filename}; #{utf8_filename}"
+        else
+          "#{disposition}"
+        end
+      end
+
+      private
+        def percent_escape(string, pattern)
+          string.gsub(pattern) do |char|
+            char.bytes.map { |byte| "%%%02X" % byte }.join
+          end
+        end
+    end
+  end
+end