gitlab-org--gitlab-foss/lib/banzai/filter/base_sanitization_filter.rb

70 lines
2.2 KiB
Ruby

# frozen_string_literal: true
module Banzai
module Filter
# Sanitize HTML produced by markup languages (Markdown, AsciiDoc...).
# Specific rules are implemented in dedicated filters:
#
# - Banzai::Filter::SanitizationFilter (Markdown)
# - Banzai::Filter::AsciiDocSanitizationFilter (AsciiDoc/Asciidoctor)
# - Banzai::Filter::BroadcastMessageSanitizationFilter (Markdown with styled links and line breaks)
#
# Extends HTML::Pipeline::SanitizationFilter with common rules.
class BaseSanitizationFilter < HTML::Pipeline::SanitizationFilter
include Gitlab::Utils::StrongMemoize
extend Gitlab::Utils::SanitizeNodeLink
UNSAFE_PROTOCOLS = %w(data javascript vbscript).freeze
def whitelist
strong_memoize(:whitelist) do
whitelist = super.deep_dup
# Allow span elements
whitelist[:elements].push('span')
# Allow data-math-style attribute in order to support LaTeX formatting
whitelist[:attributes]['code'] = %w(data-math-style)
whitelist[:attributes]['pre'] = %w(data-math-style)
# Allow html5 details/summary elements
whitelist[:elements].push('details')
whitelist[:elements].push('summary')
# Allow abbr elements with title attribute
whitelist[:elements].push('abbr')
whitelist[:attributes]['abbr'] = %w(title)
# Disallow `name` attribute globally, allow on `a`
whitelist[:attributes][:all].delete('name')
whitelist[:attributes]['a'].push('name')
# Allow any protocol in `a` elements
# and then remove links with unsafe protocols
whitelist[:protocols].delete('a')
whitelist[:transformers].push(self.class.method(:remove_unsafe_links))
# Remove `rel` attribute from `a` elements
whitelist[:transformers].push(self.class.remove_rel)
customize_whitelist(whitelist)
end
end
def customize_whitelist(whitelist)
raise NotImplementedError
end
class << self
def remove_rel
lambda do |env|
if env[:node_name] == 'a'
env[:node].remove_attribute('rel')
end
end
end
end
end
end
end