app/lib/request.rb

   1 # frozen_string_literal: true
   2
   3 require 'ipaddr'
   4 require 'socket'
   5 require 'resolv'
   6
   7 # Monkey-patch the HTTP.rb timeout class to avoid using a timeout block
   8 # around the Socket#open method, since we use our own timeout blocks inside
   9 # that method
  10 class HTTP::Timeout::PerOperation
  11   def connect(socket_class, host, port, nodelay = false)
  12     @socket = socket_class.open(host, port)
  13     @socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1) if nodelay
  14   end
  15 end
  16
  17 class Request
  18   REQUEST_TARGET = '(request-target)'
  19
  20   # We enforce a 5s timeout on DNS resolving, 5s timeout on socket opening
  21   # and 5s timeout on the TLS handshake, meaning the worst case should take
  22   # about 15s in total
  23   TIMEOUT = { connect: 5, read: 10, write: 10 }.freeze
  24
  25   include RoutingHelper
  26
  27   def initialize(verb, url, **options)
  28     raise ArgumentError if url.blank?
  29
  30     @verb        = verb
  31     @url         = Addressable::URI.parse(url).normalize
  32     @http_client = options.delete(:http_client)
  33     @options     = options.merge(socket_class: use_proxy? ? ProxySocket : Socket)
  34     @options     = @options.merge(Rails.configuration.x.http_client_proxy) if use_proxy?
  35     @headers     = {}
  36
  37     raise Mastodon::HostValidationError, 'Instance does not support hidden service connections' if block_hidden_service?
  38
  39     set_common_headers!
  40     set_digest! if options.key?(:body)
  41   end
  42
  43   def on_behalf_of(account, key_id_format = :uri, sign_with: nil)
  44     raise ArgumentError, 'account must not be nil' if account.nil?
  45
  46     @account       = account
  47     @keypair       = sign_with.present? ? OpenSSL::PKey::RSA.new(sign_with) : @account.keypair
  48     @key_id_format = key_id_format
  49
  50     self
  51   end
  52
  53   def add_headers(new_headers)
  54     @headers.merge!(new_headers)
  55     self
  56   end
  57
  58   def perform
  59     begin
  60       response = http_client.public_send(@verb, @url.to_s, @options.merge(headers: headers))
  61     rescue => e
  62       raise e.class, "#{e.message} on #{@url}", e.backtrace[0]
  63     end
  64
  65     begin
  66       response = response.extend(ClientLimit)
  67
  68       # If we are using a persistent connection, we have to
  69       # read every response to be able to move forward at all.
  70       # However, simply calling #to_s or #flush may not be safe,
  71       # as the response body, if malicious, could be too big
  72       # for our memory. So we use the #body_with_limit method
  73       response.body_with_limit if http_client.persistent?
  74
  75       yield response if block_given?
  76     rescue => e
  77       raise e.class, e.message, e.backtrace[0]
  78     ensure
  79       http_client.close unless http_client.persistent?
  80     end
  81   end
  82
  83   def headers
  84     (@account ? @headers.merge('Signature' => signature) : @headers).without(REQUEST_TARGET)
  85   end
  86
  87   class << self
  88     def valid_url?(url)
  89       begin
  90         parsed_url = Addressable::URI.parse(url)
  91       rescue Addressable::URI::InvalidURIError
  92         return false
  93       end
  94
  95       %w(http https).include?(parsed_url.scheme) && parsed_url.host.present?
  96     end
  97
  98     def http_client
  99       HTTP.use(:auto_inflate).timeout(TIMEOUT.dup).follow(max_hops: 2)
 100     end
 101   end
 102
 103   private
 104
 105   def set_common_headers!
 106     @headers[REQUEST_TARGET]    = "#{@verb} #{@url.path}"
 107     @headers['User-Agent']      = Mastodon::Version.user_agent
 108     @headers['Host']            = @url.host
 109     @headers['Date']            = Time.now.utc.httpdate
 110     @headers['Accept-Encoding'] = 'gzip' if @verb != :head
 111   end
 112
 113   def set_digest!
 114     @headers['Digest'] = "SHA-256=#{Digest::SHA256.base64digest(@options[:body])}"
 115   end
 116
 117   def signature
 118     algorithm = 'rsa-sha256'
 119     signature = Base64.strict_encode64(@keypair.sign(OpenSSL::Digest::SHA256.new, signed_string))
 120
 121     "keyId=\"#{key_id}\",algorithm=\"#{algorithm}\",headers=\"#{signed_headers.keys.join(' ').downcase}\",signature=\"#{signature}\""
 122   end
 123
 124   def signed_string
 125     signed_headers.map { |key, value| "#{key.downcase}: #{value}" }.join("\n")
 126   end
 127
 128   def signed_headers
 129     @headers.without('User-Agent', 'Accept-Encoding')
 130   end
 131
 132   def key_id
 133     case @key_id_format
 134     when :acct
 135       @account.to_webfinger_s
 136     when :uri
 137       [ActivityPub::TagManager.instance.uri_for(@account), '#main-key'].join
 138     end
 139   end
 140
 141   def http_client
 142     @http_client ||= Request.http_client
 143   end
 144
 145   def use_proxy?
 146     Rails.configuration.x.http_client_proxy.present?
 147   end
 148
 149   def block_hidden_service?
 150     !Rails.configuration.x.access_to_hidden_service && /\.(onion|i2p)$/.match(@url.host)
 151   end
 152
 153   module ClientLimit
 154     def body_with_limit(limit = 1.megabyte)
 155       raise Mastodon::LengthValidationError if content_length.present? && content_length > limit
 156
 157       if charset.nil?
 158         encoding = Encoding::BINARY
 159       else
 160         begin
 161           encoding = Encoding.find(charset)
 162         rescue ArgumentError
 163           encoding = Encoding::BINARY
 164         end
 165       end
 166
 167       contents = String.new(encoding: encoding)
 168
 169       while (chunk = readpartial)
 170         contents << chunk
 171         chunk.clear
 172
 173         raise Mastodon::LengthValidationError if contents.bytesize > limit
 174       end
 175
 176       contents
 177     end
 178   end
 179
 180   class Socket < TCPSocket
 181     class << self
 182       def open(host, *args)
 183         outer_e = nil
 184         port    = args.first
 185
 186         addresses = []
 187         begin
 188           addresses = [IPAddr.new(host)]
 189         rescue IPAddr::InvalidAddressError
 190           Resolv::DNS.open do |dns|
 191             dns.timeouts = 5
 192             addresses = dns.getaddresses(host).take(2)
 193           end
 194         end
 195
 196         socks = []
 197         addr_by_socket = {}
 198
 199         addresses.each do |address|
 200           begin
 201             check_private_address(address)
 202
 203             sock     = ::Socket.new(address.is_a?(Resolv::IPv6) ? ::Socket::AF_INET6 : ::Socket::AF_INET, ::Socket::SOCK_STREAM, 0)
 204             sockaddr = ::Socket.pack_sockaddr_in(port, address.to_s)
 205
 206             sock.setsockopt(::Socket::IPPROTO_TCP, ::Socket::TCP_NODELAY, 1)
 207
 208             sock.connect_nonblock(sockaddr)
 209
 210             # If that hasn't raised an exception, we somehow managed to connect
 211             # immediately, close pending sockets and return immediately
 212             socks.each(&:close)
 213             return sock
 214           rescue IO::WaitWritable
 215             socks << sock
 216             addr_by_socket[sock] = sockaddr
 217           rescue => e
 218             outer_e = e
 219           end
 220         end
 221
 222         until socks.empty?
 223           _, available_socks, = IO.select(nil, socks, nil, Request::TIMEOUT[:connect])
 224
 225           if available_socks.nil?
 226             socks.each(&:close)
 227             raise HTTP::TimeoutError, "Connect timed out after #{Request::TIMEOUT[:connect]} seconds"
 228           end
 229
 230           available_socks.each do |sock|
 231             socks.delete(sock)
 232
 233             begin
 234               sock.connect_nonblock(addr_by_socket[sock])
 235             rescue Errno::EISCONN
 236             rescue => e
 237               sock.close
 238               outer_e = e
 239               next
 240             end
 241
 242             socks.each(&:close)
 243             return sock
 244           end
 245         end
 246
 247         if outer_e
 248           raise outer_e
 249         else
 250           raise SocketError, "No address for #{host}"
 251         end
 252       end
 253
 254       alias new open
 255
 256       def check_private_address(address)
 257         raise Mastodon::HostValidationError if PrivateAddressCheck.private_address?(IPAddr.new(address.to_s))
 258       end
 259     end
 260   end
 261
 262   class ProxySocket < Socket
 263     class << self
 264       def check_private_address(_address)
 265         # Accept connections to private addresses as HTTP proxies will usually
 266         # be on local addresses
 267         nil
 268       end
 269     end
 270   end
 271
 272   private_constant :ClientLimit, :Socket, :ProxySocket
 273 end