# Make sure HOME is set, regardless of OS, so that File.expand_path works # as expected with tilde characters. ENV['HOME'] ||= ENV['HOMEPATH'] ? "#{ENV['HOMEDRIVE']}#{ENV['HOMEPATH']}" : Dir.pwd require 'logger' require 'etc' require 'shellwords' require 'net/ssh/config' require 'net/ssh/errors' require 'net/ssh/loggable' require 'net/ssh/transport/session' require 'net/ssh/authentication/session' require 'net/ssh/connection/session' require 'net/ssh/prompt' module Net # Net::SSH is a library for interacting, programmatically, with remote # processes via the SSH2 protocol. Sessions are always initiated via # Net::SSH.start. From there, a program interacts with the new SSH session # via the convenience methods on Net::SSH::Connection::Session, by opening # and interacting with new channels (Net::SSH::Connection:Session#open_channel # and Net::SSH::Connection::Channel), or by forwarding local and/or # remote ports through the connection (Net::SSH::Service::Forward). # # The SSH protocol is very event-oriented. Requests are sent from the client # to the server, and are answered asynchronously. This gives great flexibility # (since clients can have multiple requests pending at a time), but it also # adds complexity. Net::SSH tries to manage this complexity by providing # some simpler methods of synchronous communication (see Net::SSH::Connection::Session#exec!). # # In general, though, and if you want to do anything more complicated than # simply executing commands and capturing their output, you'll need to use # channels (Net::SSH::Connection::Channel) to build state machines that are # executed while the event loop runs (Net::SSH::Connection::Session#loop). # # Net::SSH::Connection::Session and Net::SSH::Connection::Channel have more # information about this technique. # # = "Um, all I want to do is X, just show me how!" # # == X == "execute a command and capture the output" # # Net::SSH.start("host", "user", password: "password") do |ssh| # result = ssh.exec!("ls -l") # puts result # end # # == X == "forward connections on a local port to a remote host" # # Net::SSH.start("host", "user", password: "password") do |ssh| # ssh.forward.local(1234, "www.google.com", 80) # ssh.loop { true } # end # # == X == "forward connections on a remote port to the local host" # # Net::SSH.start("host", "user", password: "password") do |ssh| # ssh.forward.remote(80, "www.google.com", 1234) # ssh.loop { true } # end module SSH # This is the set of options that Net::SSH.start recognizes. See # Net::SSH.start for a description of each option. VALID_OPTIONS = %i[ auth_methods bind_address compression compression_level config encryption forward_agent hmac host_key remote_user keepalive keepalive_interval keepalive_maxcount kex keys key_data keycerts languages logger paranoid password port proxy rekey_blocks_limit rekey_limit rekey_packet_limit timeout verbose known_hosts global_known_hosts_file user_known_hosts_file host_key_alias host_name user properties passphrase keys_only max_pkt_size max_win_size send_env set_env use_agent number_of_password_prompts append_all_supported_algorithms non_interactive password_prompt agent_socket_factory minimum_dh_bits verify_host_key fingerprint_hash check_host_ip ] # The standard means of starting a new SSH connection. When used with a # block, the connection will be closed when the block terminates, otherwise # the connection will just be returned. The yielded (or returned) value # will be an instance of Net::SSH::Connection::Session (q.v.). (See also # Net::SSH::Connection::Channel and Net::SSH::Service::Forward.) # # Net::SSH.start("host", "user") do |ssh| # ssh.exec! "cp /some/file /another/location" # hostname = ssh.exec!("hostname") # # ssh.open_channel do |ch| # ch.exec "sudo -p 'sudo password: ' ls" do |ch, success| # abort "could not execute sudo ls" unless success # # ch.on_data do |ch, data| # print data # if data =~ /sudo password: / # ch.send_data("password\n") # end # end # end # end # # ssh.loop # end # # This method accepts the following options (all are optional): # # * :auth_methods => an array of authentication methods to try # * :bind_address => the IP address on the connecting machine to use in # establishing connection. (:bind_address is discarded if :proxy # is set.) # * :check_host_ip => Also ckeck IP address when connecting to remote host. # Defaults to +true+. # * :compression => the compression algorithm to use, or +true+ to use # whatever is supported. # * :compression_level => the compression level to use when sending data # * :config => set to +true+ to load the default OpenSSH config files # (~/.ssh/config, /etc/ssh_config), or to +false+ to not load them, or to # a file-name (or array of file-names) to load those specific configuration # files. Defaults to +true+. # * :encryption => the encryption cipher (or ciphers) to use # * :forward_agent => set to true if you want the SSH agent connection to # be forwarded # * :known_hosts => a custom object holding known hosts records. # It must implement #search_for and `add` in a similiar manner as KnownHosts. # * :global_known_hosts_file => the location of the global known hosts # file. Set to an array if you want to specify multiple global known # hosts files. Defaults to %w(/etc/ssh/ssh_known_hosts /etc/ssh/ssh_known_hosts2). # * :hmac => the hmac algorithm (or algorithms) to use # * :host_key => the host key algorithm (or algorithms) to use # * :host_key_alias => the host name to use when looking up or adding a # host to a known_hosts dictionary file # * :host_name => the real host name or IP to log into. This is used # instead of the +host+ parameter, and is primarily only useful when # specified in an SSH configuration file. It lets you specify an # "alias", similarly to adding an entry in /etc/hosts but without needing # to modify /etc/hosts. # * :keepalive => set to +true+ to send a keepalive packet to the SSH server # when there's no traffic between the SSH server and Net::SSH client for # the keepalive_interval seconds. Defaults to +false+. # * :keepalive_interval => the interval seconds for keepalive. # Defaults to +300+ seconds. # * :keepalive_maxcount => the maximun number of keepalive packet miss allowed. # Defaults to 3 # * :kex => the key exchange algorithm (or algorithms) to use # * :keys => an array of file names of private keys to use for publickey # and hostbased authentication # * :keycerts => an array of file names of key certificates to use # with publickey authentication # * :key_data => an array of strings, with each element of the array being # a raw private key in PEM format. # * :keys_only => set to +true+ to use only private keys from +keys+ and # +key_data+ parameters, even if ssh-agent offers more identities. This # option is intended for situations where ssh-agent offers many different # identites. # * :logger => the logger instance to use when logging # * :max_pkt_size => maximum size we tell the other side that is supported per # packet. Default is 0x8000 (32768 bytes). Increase to 0x10000 (65536 bytes) # for better performance if your SSH server supports it (most do). # * :max_win_size => maximum size we tell the other side that is supported for # the window. # * :non_interactive => set to true if your app is non interactive and prefers # authentication failure vs password prompt. Non-interactive applications # should set it to true to prefer failing a password/etc auth methods vs. # asking for password. # * :paranoid => deprecated alias for :verify_host_key # * :passphrase => the passphrase to use when loading a private key (default # is +nil+, for no passphrase) # * :password => the password to use to login # * :port => the port to use when connecting to the remote host # * :properties => a hash of key/value pairs to add to the new connection's # properties (see Net::SSH::Connection::Session#properties) # * :proxy => a proxy instance (see Proxy) to use when connecting # * :rekey_blocks_limit => the max number of blocks to process before rekeying # * :rekey_limit => the max number of bytes to process before rekeying # * :rekey_packet_limit => the max number of packets to process before rekeying # * :send_env => an array of local environment variable names to export to the # remote environment. Names may be given as String or Regexp. # * :set_env => a hash of environment variable names and values to set to the # remote environment. Override the ones if specified in +send_env+. # * :timeout => how long to wait for the initial connection to be made # * :user => the user name to log in as; this overrides the +user+ # parameter, and is primarily only useful when provided via an SSH # configuration file. # * :remote_user => used for substitution into the '%r' part of a ProxyCommand # * :user_known_hosts_file => the location of the user known hosts file. # Set to an array to specify multiple user known hosts files. # Defaults to %w(~/.ssh/known_hosts ~/.ssh/known_hosts2). # * :use_agent => Set false to disable the use of ssh-agent. Defaults to # true # * :verbose => how verbose to be (Logger verbosity constants, Logger::DEBUG # is very verbose, Logger::FATAL is all but silent). Logger::FATAL is the # default. The symbols :debug, :info, :warn, :error, and :fatal are also # supported and are translated to the corresponding Logger constant. # * :append_all_supported_algorithms => set to +true+ to append all supported # algorithms by net-ssh. Was the default behaviour until 2.10 # * :number_of_password_prompts => Number of prompts for the password # authentication method defaults to 3 set to 0 to disable prompt for # password auth method # * :password_prompt => a custom prompt object with ask method. See Net::SSH::Prompt # # * :agent_socket_factory => enables the user to pass a lambda/block that will serve as the socket factory # Net::SSH.start(host,user,agent_socket_factory: ->{ UNIXSocket.open('/foo/bar') }) # example: ->{ UNIXSocket.open('/foo/bar')} # * :verify_host_key => specify how strict host-key verification should be. # In order of increasing strictness: # * :never (very insecure) ::Net::SSH::Verifiers::Never # * :accept_new_or_local_tunnel (insecure) ::Net::SSH::Verifiers::AcceptNewOrLocalTunnel # * :accept_new (insecure) ::Net::SSH::Verifiers::AcceptNew # * :always (secure) ::Net::SSH::Verifiers::Always # You can also provide an own Object which responds to +verify+. The argument # given to +verify+ is a hash consisting of the +:key+, the +:key_blob+, # the +:fingerprint+ and the +:session+. Returning true accepts the host key, # returning false declines it and closes the connection. # * :fingerprint_hash => 'MD5' or 'SHA256', defaults to 'SHA256' # If +user+ parameter is nil it defaults to USER from ssh_config, or # local username def self.start(host, user = nil, options = {}, &block) invalid_options = options.keys - VALID_OPTIONS if invalid_options.any? raise ArgumentError, "invalid option(s): #{invalid_options.join(', ')}" end assign_defaults(options) _sanitize_options(options) options[:user] = user if user options = configuration_for(host, options.fetch(:config, true)).merge(options) host = options.fetch(:host_name, host) options[:check_host_ip] = true unless options.key?(:check_host_ip) if options[:non_interactive] options[:number_of_password_prompts] = 0 end _support_deprecated_option_paranoid(options) if options[:verbose] options[:logger].level = case options[:verbose] when Integer then options[:verbose] when :debug then Logger::DEBUG when :info then Logger::INFO when :warn then Logger::WARN when :error then Logger::ERROR when :fatal then Logger::FATAL else raise ArgumentError, "can't convert #{options[:verbose].inspect} to any of the Logger level constants" end end transport = Transport::Session.new(host, options) auth = Authentication::Session.new(transport, options) user = options.fetch(:user, user) || Etc.getpwuid.name if auth.authenticate("ssh-connection", user, options[:password]) connection = Connection::Session.new(transport, options) if block_given? begin yield connection ensure connection.close unless connection.closed? end else return connection end else transport.close raise AuthenticationFailed, "Authentication failed for user #{user}@#{host}" end end # Returns a hash of the configuration options for the given host, as read # from the SSH configuration file(s). If +use_ssh_config+ is true (the # default), this will load configuration from both ~/.ssh/config and # /etc/ssh_config. If +use_ssh_config+ is nil or false, nothing will be # loaded (and an empty hash returned). Otherwise, +use_ssh_config+ may # be a file name (or array of file names) of SSH configuration file(s) # to read. # # See Net::SSH::Config for the full description of all supported options. def self.configuration_for(host, use_ssh_config) files = case use_ssh_config when true then Net::SSH::Config.expandable_default_files when false, nil then return {} else Array(use_ssh_config) end Net::SSH::Config.for(host, files) end def self.assign_defaults(options) if !options[:logger] options[:logger] = Logger.new(STDERR) options[:logger].level = Logger::FATAL end options[:password_prompt] ||= Prompt.default(options) %i[password passphrase].each do |key| options.delete(key) if options.key?(key) && options[key].nil? end end def self._sanitize_options(options) invalid_option_values = [nil, [nil]] unless (options.values & invalid_option_values).empty? nil_options = options.select { |_k, v| invalid_option_values.include?(v) }.map(&:first) Kernel.warn "#{caller_locations(2, 1)[0]}: Passing nil, or [nil] to Net::SSH.start is deprecated for keys: #{nil_options.join(', ')}" end end private_class_method :_sanitize_options def self._support_deprecated_option_paranoid(options) if options.key?(:paranoid) Kernel.warn( ":paranoid is deprecated, please use :verify_host_key. Supported " \ "values are exactly the same, only the name of the option has changed." ) if options.key?(:verify_host_key) Kernel.warn( "Both :paranoid and :verify_host_key were specified. " \ ":verify_host_key takes precedence, :paranoid will be ignored." ) else options[:verify_host_key] = options.delete(:paranoid) end end end private_class_method :_support_deprecated_option_paranoid end end