1 files changed, 116 insertions, 0 deletions
diff --git a/actionview/lib/action_view/helpers/sanitize_helper/sanitizers.rb b/actionview/lib/action_view/helpers/sanitize_helper/sanitizers.rb
new file mode 100644
index 0000000000..74be525581
--- /dev/null
+++ b/actionview/lib/action_view/helpers/sanitize_helper/sanitizers.rb
@@ -0,0 +1,116 @@
+require 'active_support/core_ext/class/attribute'
+require 'active_support/deprecation'
+require 'loofah'
+
+module ActionView
+
+  class FullSanitizer
+    def sanitize(html, options = {})
+      Loofah.fragment(html).text
+    end
+  end
+
+  class LinkSanitizer
+    def initialize
+      @link_scrubber = Loofah::Scrubber.new do |node|
+        next unless node.name == 'a'
+        node.before node.children
+        node.remove
+      end
+    end
+
+    def sanitize(html, options = {})
+      Loofah.scrub_fragment(html, @link_scrubber).to_s
+    end
+  end
+
+  class WhiteListSanitizer
+    def sanitize(html, options = {})
+      return nil unless html
+      validate_options(options)
+
+      loofah_fragment = Loofah.fragment(html)
+      loofah_fragment.scrub!(:strip)
+      loofah_fragment.xpath("./form").each { |form| form.remove }
+      loofah_fragment.to_s
+    end
+
+    def sanitize_css(style_string)
+      Loofah::HTML5::Scrub.scrub_css style_string
+    end
+
+    def protocol_separator
+      ActiveSupport::Deprecation.warn('protocol_separator has been deprecated and has no effect.')
+    end
+
+    def protocol_separator=(value)
+      ActiveSupport::Deprecation.warn('protocol_separator= has been deprecated and has no effect.')
+    end
+
+    def bad_tags
+      ActiveSupport::Deprecation.warn('bad_tags has been deprecated and has no effect.')
+    end
+
+    class << self
+      def protocol_separator
+        ActiveSupport::Deprecation.warn('protocol_separator has been deprecated and has no effect.')
+      end
+
+      def protocol_separator=(value)
+        ActiveSupport::Deprecation.warn('protocol_separator= has been deprecated and has no effect.')
+      end
+
+      def bad_tags
+        ActiveSupport::Deprecation.warn('The bad_tags class attribute has been deprecated and has no effect. You can still affect the tags being sanitized using bad_tags= which changes the allowed_tags.')
+      end
+
+      def bad_tags=(tags)
+        allowed_tags.replace(allowed_tags - tags)
+      end
+    end
+
+    [:uri_attributes, :allowed_attributes,
+    :allowed_tags, :allowed_protocols, :allowed_css_properties,
+    :allowed_css_keywords, :shorthand_css_properties].each do |attr|
+      class_attribute attr, :instance_writer => false
+
+      define_method "#{self}.update_#{attr}" do |arg|
+        attr.merge arg
+      end
+    end
+
+    # Constants are from Loofahs source at lib/loofah/html5/whitelist.rb
+    self.uri_attributes = Loofah::HTML5::WhiteList::ATTR_VAL_IS_URI
+
+    self.allowed_tags = Loofah::HTML5::WhiteList::ALLOWED_ELEMENTS
+
+    self.bad_tags = Set.new %w(script)
+
+    self.allowed_attributes = Loofah::HTML5::WhiteList::ALLOWED_ATTRIBUTES
+
+    self.allowed_css_properties = Loofah::HTML5::WhiteList::ALLOWED_CSS_PROPERTIES
+
+    self.allowed_css_keywords = Loofah::HTML5::WhiteList::ALLOWED_CSS_KEYWORDS
+
+    self.shorthand_css_properties = Loofah::HTML5::WhiteList::SHORTHAND_CSS_PROPERTIES
+
+    self.allowed_protocols = Loofah::HTML5::WhiteList::ALLOWED_PROTOCOLS
+
+    protected
+      def validate_options(options)
+        if options[:tags] && !options[:tags].is_a?(Enumerable)
+          raise ArgumentError, "You should pass :tags as an Enumerable"
+        end
+
+        if options[:attributes] && !options[:attributes].is_a?(Enumerable)
+          raise ArgumentError, "You should pass :attributes as an Enumerable"
+        end
+      end
+
+      def contains_bad_protocols?(attr_name, value)
+        protocol_separator = ':'
+        self.uri_attributes.include?(attr_name) &&
+        (value =~ /(^[^\/:]*):|(&#0*58)|(&#x70)|(&#x0*3a)|(%|&#37;)3A/i && !self.allowed_protocols.include?(value.split(protocol_separator).first.downcase.strip))
+      end
+  end
+end