gitlab-org--gitlab-foss/lib/gitlab/utils/sanitize_node_link.rb

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# frozen_string_literal: true
require_dependency 'gitlab/utils'
module Gitlab
module Utils
module SanitizeNodeLink
UNSAFE_PROTOCOLS = %w(data javascript vbscript).freeze
ATTRS_TO_SANITIZE = %w(href src data-src).freeze
def remove_unsafe_links(env, remove_invalid_links: true)
node = env[:node]
sanitize_node(node: node, remove_invalid_links: remove_invalid_links)
# HTML entities such as <video></video> have scannable attrs in
# children elements, which also need to be sanitized.
#
node.children.each do |child_node|
sanitize_node(node: child_node, remove_invalid_links: remove_invalid_links)
end
end
# Remove all invalid scheme characters before checking against the
# list of unsafe protocols.
#
# See https://tools.ietf.org/html/rfc3986#section-3.1
#
def safe_protocol?(scheme)
return false unless scheme
scheme = scheme
.strip
.downcase
.gsub(/[^A-Za-z\+\.\-]+/, '')
UNSAFE_PROTOCOLS.none?(scheme)
end
private
def sanitize_node(node:, remove_invalid_links: true)
ATTRS_TO_SANITIZE.each do |attr|
next unless node.has_attribute?(attr)
begin
node[attr] = node[attr].strip
uri = Addressable::URI.parse(node[attr])
next unless uri.scheme
next if safe_protocol?(uri.scheme)
node.remove_attribute(attr)
rescue Addressable::URI::InvalidURIError
node.remove_attribute(attr) if remove_invalid_links
end
end
end
end
end
end