require 'set' require 'active_support/core_ext/class/attribute' module HTML class Sanitizer def sanitize(text, options = {}) return text unless sanitizeable?(text) tokenize(text, options).join end def sanitizeable?(text) !(text.nil? || text.empty? || !text.index("<")) end protected def tokenize(text, options) tokenizer = HTML::Tokenizer.new(text) result = [] while token = tokenizer.next node = Node.parse(nil, 0, 0, token, false) process_node node, result, options end result end def process_node(node, result, options) result << node.to_s end end class FullSanitizer < Sanitizer def sanitize(text, options = {}) result = super # strip any comments, and if they have a newline at the end (ie. line with # only a comment) strip that too result = result.gsub(/[\n]?/m, "") if (result && result =~ /[\n]?/m) # Recurse - handle all dirty nested tags result == text ? result : sanitize(result, options) end def process_node(node, result, options) result << node.to_s if node.class == HTML::Text end end class LinkSanitizer < FullSanitizer cattr_accessor :included_tags, :instance_writer => false self.included_tags = Set.new(%w(a href)) def sanitizeable?(text) !(text.nil? || text.empty? || !((text.index(""))) end protected def process_node(node, result, options) result << node.to_s unless node.is_a?(HTML::Tag) && included_tags.include?(node.name) end end class WhiteListSanitizer < Sanitizer [:protocol_separator, :uri_attributes, :allowed_attributes, :allowed_tags, :allowed_protocols, :bad_tags, :allowed_css_properties, :allowed_css_keywords, :shorthand_css_properties].each do |attr| class_attribute attr, :instance_writer => false end # A regular expression of the valid characters used to separate protocols like # the ':' in 'http://foo.com' self.protocol_separator = /:|(�*58)|(p)|(%|%)3A/ # Specifies a Set of HTML attributes that can have URIs. self.uri_attributes = Set.new(%w(href src cite action longdesc xlink:href lowsrc)) # Specifies a Set of 'bad' tags that the #sanitize helper will remove completely, as opposed # to just escaping harmless tags like <font> self.bad_tags = Set.new(%w(script)) # Specifies the default Set of tags that the #sanitize helper will allow unscathed. self.allowed_tags = Set.new(%w(strong em b i p code pre tt samp kbd var sub sup dfn cite big small address hr br div span h1 h2 h3 h4 h5 h6 ul ol li dl dt dd abbr acronym a img blockquote del ins)) # Specifies the default Set of html attributes that the #sanitize helper will leave # in the allowed tag. self.allowed_attributes = Set.new(%w(href src width height alt cite datetime title class name xml:lang abbr)) # Specifies the default Set of acceptable css properties that #sanitize and #sanitize_css will accept. self.allowed_protocols = Set.new(%w(ed2k ftp http https irc mailto news gopher nntp telnet webcal xmpp callto feed svn urn aim rsync tag ssh sftp rtsp afs)) # Specifies the default Set of acceptable css keywords that #sanitize and #sanitize_css will accept. self.allowed_css_properties = Set.new(%w(azimuth background-color border-bottom-color border-collapse border-color border-left-color border-right-color border-top-color clear color cursor direction display elevation float font font-family font-size font-style font-variant font-weight height letter-spacing line-height overflow pause pause-after pause-before pitch pitch-range richness speak speak-header speak-numeral speak-punctuation speech-rate stress text-align text-decoration text-indent unicode-bidi vertical-align voice-family volume white-space width)) # Specifies the default Set of acceptable css keywords that #sanitize and #sanitize_css will accept. self.allowed_css_keywords = Set.new(%w(auto aqua black block blue bold both bottom brown center collapse dashed dotted fuchsia gray green !important italic left lime maroon medium none navy normal nowrap olive pointer purple red right solid silver teal top transparent underline white yellow)) # Specifies the default Set of allowed shorthand css properties for the #sanitize and #sanitize_css helpers. self.shorthand_css_properties = Set.new(%w(background border margin padding)) # Sanitizes a block of css code. Used by #sanitize when it comes across a style attribute def sanitize_css(style) # disallow urls style = style.to_s.gsub(/url\s*\(\s*[^\s)]+?\s*\)\s*/, ' ') # gauntlet if style !~ /^([:,;#%.\sa-zA-Z0-9!]|\w-\w|\'[\s\w]+\'|\"[\s\w]+\"|\([\d,\s]+\))*$/ || style !~ /^(\s*[-\w]+\s*:\s*[^:;]*(;|$)\s*)*$/ return '' end clean = [] style.scan(/([-\w]+)\s*:\s*([^:;]*)/) do |prop,val| if allowed_css_properties.include?(prop.downcase) clean << prop + ': ' + val + ';' elsif shorthand_css_properties.include?(prop.split('-')[0].downcase) unless val.split().any? do |keyword| !allowed_css_keywords.include?(keyword) && keyword !~ /^(#[0-9a-f]+|rgb\(\d+%?,\d*%?,?\d*%?\)?|\d{0,2}\.?\d{0,2}(cm|em|ex|in|mm|pc|pt|px|%|,|\))?)$/ end clean << prop + ': ' + val + ';' end end end clean.join(' ') end protected def tokenize(text, options) options[:parent] = [] options[:attributes] ||= allowed_attributes options[:tags] ||= allowed_tags super end def process_node(node, result, options) result << case node when HTML::Tag if node.closing == :close options[:parent].shift else options[:parent].unshift node.name end process_attributes_for node, options options[:tags].include?(node.name) ? node : nil else bad_tags.include?(options[:parent].first) ? nil : node.to_s.gsub(/