gitlab-ce/lib/api/validations/validators/file_path.rb

41 lines
1.6 KiB
Ruby

# frozen_string_literal: true
module API
module Validations
module Validators
class FilePath < Grape::Validations::Validators::Base
def validate_param!(attr_name, params)
options = @option.is_a?(Hash) ? @option : {}
path_allowlist = options.fetch(:allowlist, [])
allow_initial_path_separator = options.fetch(:allow_initial_path_separator, false)
path = params[attr_name]
if allow_initial_path_separator
decoded_path = ::Gitlab::Utils.decode_path(path)
path_was_encoded = decoded_path != path
if path_was_encoded && decoded_path.start_with?('/')
# NOTE: This validation assumes downstream code will NOT decode the path again
# after validation. If any component calls CGI.unescape() or similar decoding methods
# on the validated path, it could bypass security checks. The path should be used
# as-is after validation to maintain security guarantees.
segments = decoded_path.split('/')
if segments.length > 1 && segments[0].empty?
first_dir = "/#{segments[1]}"
path_allowlist << first_dir unless first_dir == '/'
end
end
end
Gitlab::PathTraversal.check_allowed_absolute_path_and_path_traversal!(path, path_allowlist)
rescue StandardError
raise Grape::Exceptions::Validation.new(
params: [@scope.full_name(attr_name)],
message: "should be a valid file path"
)
end
end
end
end
end