102ed6e8ca
* Tighten allowed HTML in oEmbed-based preview cards * Sanitize preview cards at render time * Add `sandbox` attribute to preview card iframes
119 lines
2.8 KiB
Ruby
119 lines
2.8 KiB
Ruby
# frozen_string_literal: true
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class Sanitize
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module Config
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HTTP_PROTOCOLS = %w(
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http
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https
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).freeze
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LINK_PROTOCOLS = %w(
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http
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https
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dat
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dweb
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ipfs
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ipns
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ssb
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gopher
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xmpp
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magnet
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gemini
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).freeze
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CLASS_WHITELIST_TRANSFORMER = lambda do |env|
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node = env[:node]
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class_list = node['class']&.split(/[\t\n\f\r ]/)
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return unless class_list
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class_list.keep_if do |e|
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next true if /^(h|p|u|dt|e)-/.match?(e) # microformats classes
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next true if /^(mention|hashtag)$/.match?(e) # semantic classes
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next true if /^(ellipsis|invisible)$/.match?(e) # link formatting classes
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end
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node['class'] = class_list.join(' ')
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end
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UNSUPPORTED_HREF_TRANSFORMER = lambda do |env|
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return unless env[:node_name] == 'a'
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current_node = env[:node]
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scheme = begin
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if current_node['href'] =~ Sanitize::REGEX_PROTOCOL
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Regexp.last_match(1).downcase
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else
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:relative
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end
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end
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current_node.replace(current_node.text) unless LINK_PROTOCOLS.include?(scheme)
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end
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UNSUPPORTED_ELEMENTS_TRANSFORMER = lambda do |env|
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return unless %w(h1 h2 h3 h4 h5 h6 blockquote pre ul ol li).include?(env[:node_name])
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current_node = env[:node]
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case env[:node_name]
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when 'li'
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current_node.traverse do |node|
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next unless %w(p ul ol li).include?(node.name)
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node.add_next_sibling('<br>') if node.next_sibling
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node.replace(node.children) unless node.text?
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end
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else
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current_node.name = 'p'
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end
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end
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MASTODON_STRICT ||= freeze_config(
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elements: %w(p br span a),
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attributes: {
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'a' => %w(href rel class),
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'span' => %w(class),
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},
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add_attributes: {
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'a' => {
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'rel' => 'nofollow noopener noreferrer',
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'target' => '_blank',
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},
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},
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protocols: {},
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transformers: [
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CLASS_WHITELIST_TRANSFORMER,
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UNSUPPORTED_ELEMENTS_TRANSFORMER,
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UNSUPPORTED_HREF_TRANSFORMER,
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]
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)
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MASTODON_OEMBED ||= freeze_config(
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elements: %w(audio embed iframe source video),
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attributes: {
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'audio' => %w(controls),
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'embed' => %w(height src type width),
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'iframe' => %w(allowfullscreen frameborder height scrolling src width),
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'source' => %w(src type),
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'video' => %w(controls height loop width),
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},
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protocols: {
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'embed' => { 'src' => HTTP_PROTOCOLS },
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'iframe' => { 'src' => HTTP_PROTOCOLS },
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'source' => { 'src' => HTTP_PROTOCOLS },
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},
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add_attributes: {
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'iframe' => { 'sandbox' => 'allow-scripts allow-same-origin allow-popups allow-popups-to-escape-sandbox allow-forms' },
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}
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)
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end
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end
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