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# frozen_string_literal: true
require 'resolv'
require 'ipaddress'
module Gitlab
class UrlBlocker
BlockedUrlError = Class.new(StandardError)
class << self
def validate!(url, ports: [], protocols: [], allow_localhost: false, allow_local_network: true, ascii_only: false, enforce_user: false)
return true if url.nil?
# Param url can be a string, URI or Addressable::URI
uri = parse_url(url)
# Allow imports from the GitLab instance itself but only from the configured ports
return true if internal?(uri)
port = uri.port || uri.default_port
validate_protocol!(uri.scheme, protocols)
validate_port!(port, ports) if ports.any?
validate_user!(uri.user) if enforce_user
validate_hostname!(uri.hostname)
validate_unicode_restriction!(uri) if ascii_only
begin
addrs_info = Addrinfo.getaddrinfo(uri.hostname, port, nil, :STREAM).map do |addr|
addr.ipv6_v4mapped? ? addr.ipv6_to_ipv4 : addr
end
rescue SocketError
return true
end
validate_localhost!(addrs_info) unless allow_localhost
validate_loopback!(addrs_info) unless allow_localhost
validate_local_network!(addrs_info) unless allow_local_network
validate_link_local!(addrs_info) unless allow_local_network
true
end
def blocked_url?(*args)
validate!(*args)
false
rescue BlockedUrlError
true
end
private
def parse_url(url)
raise Addressable::URI::InvalidURIError if multiline?(url)
Addressable::URI.parse(url)
rescue Addressable::URI::InvalidURIError, URI::InvalidURIError
raise BlockedUrlError, 'URI is invalid'
end
def multiline?(url)
CGI.unescape(url.to_s) =~ /\n|\r/
end
def validate_port!(port, ports)
return if port.blank?
# Only ports under 1024 are restricted
return if port >= 1024
return if ports.include?(port)
raise BlockedUrlError, "Only allowed ports are #{ports.join(', ')}, and any over 1024"
end
def validate_protocol!(protocol, protocols)
if protocol.blank? || (protocols.any? && !protocols.include?(protocol))
raise BlockedUrlError, "Only allowed protocols are #{protocols.join(', ')}"
end
end
def validate_user!(value)
return if value.blank?
return if value =~ /\A\p{Alnum}/
raise BlockedUrlError, "Username needs to start with an alphanumeric character"
end
def validate_hostname!(value)
return if value.blank?
return if IPAddress.valid?(value)
return if value =~ /\A\p{Alnum}/
raise BlockedUrlError, "Hostname or IP address invalid"
end
def validate_unicode_restriction!(uri)
return if uri.to_s.ascii_only?
raise BlockedUrlError, "URI must be ascii only #{uri.to_s.dump}"
end
def validate_localhost!(addrs_info)
local_ips = ["::", "0.0.0.0"]
local_ips.concat(Socket.ip_address_list.map(&:ip_address))
return if (local_ips & addrs_info.map(&:ip_address)).empty?
raise BlockedUrlError, "Requests to localhost are not allowed"
end
def validate_loopback!(addrs_info)
return unless addrs_info.any? { |addr| addr.ipv4_loopback? || addr.ipv6_loopback? }
raise BlockedUrlError, "Requests to loopback addresses are not allowed"
end
def validate_local_network!(addrs_info)
return unless addrs_info.any? { |addr| addr.ipv4_private? || addr.ipv6_sitelocal? || addr.ipv6_unique_local? }
raise BlockedUrlError, "Requests to the local network are not allowed"
end
def validate_link_local!(addrs_info)
netmask = IPAddr.new('169.254.0.0/16')
return unless addrs_info.any? { |addr| addr.ipv6_linklocal? || netmask.include?(addr.ip_address) }
raise BlockedUrlError, "Requests to the link local network are not allowed"
end
def internal?(uri)
internal_web?(uri) || internal_shell?(uri)
end
def internal_web?(uri)
uri.scheme == config.gitlab.protocol &&
uri.hostname == config.gitlab.host &&
(uri.port.blank? || uri.port == config.gitlab.port)
end
def internal_shell?(uri)
uri.scheme == 'ssh' &&
uri.hostname == config.gitlab_shell.ssh_host &&
(uri.port.blank? || uri.port == config.gitlab_shell.ssh_port)
end
def config
Gitlab.config
end
end
end
end
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