Class: Bolt::Transport::SSH::Connection

Inherits:
Bolt::Transport::Sudoable::Connection show all
Defined in:
lib/bolt/transport/ssh/connection.rb

Constant Summary collapse

PAGEANT_NAME = 
"Pageant\0".encode(Encoding::UTF_16LE)

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Bolt::Transport::Sudoable::Connection

#build_sudoable_command_str, #inject_interpreter, #make_executable, #make_tempdir, #prepend_sudo_success, #run_as, #running_as, #with_tempdir, #write_executable

Constructor Details

#initialize(target, transport_logger) ⇒ Connection

Returns a new instance of Connection.

Raises:



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# File 'lib/bolt/transport/ssh/connection.rb', line 17

def initialize(target, transport_logger)
  # lazy-load expensive gem code
  require 'net/ssh'
  require 'net/ssh/proxy/jump'

  raise Bolt::ValidationError, "Target #{target.name} does not have a host" unless target.host
  @sudo_id = SecureRandom.uuid

  @target = target
  @load_config = target.options['load-config']

  ssh_config = @load_config ? Net::SSH::Config.for(target.host) : {}
  @user = @target.user || ssh_config[:user] || Etc.getlogin
  @run_as = nil
  @strict_host_key_checking = ssh_config[:strict_host_key_checking]

  @logger = Logging.logger[@target.host]
  @transport_logger = transport_logger

  if target.options['private-key']&.instance_of?(String)
    begin
      Bolt::Util.validate_file('ssh key', target.options['private-key'])
    rescue Bolt::FileError => e
      @logger.warn(e.msg)
    end
  end
end

Instance Attribute Details

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# File 'lib/bolt/transport/ssh/connection.rb', line 14

def logger
  @logger
end

#run_as=(value) ⇒ Object (writeonly)

Sets the attribute run_as

Parameters:

  • value —

    the value to set the attribute run_as to.



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# File 'lib/bolt/transport/ssh/connection.rb', line 15

def run_as=(value)
  @run_as = value
end

#target ⇒ Object (readonly)

Returns the value of attribute target.



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# File 'lib/bolt/transport/ssh/connection.rb', line 14

def target
  @target
end

#user ⇒ Object (readonly)

Returns the value of attribute user.



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# File 'lib/bolt/transport/ssh/connection.rb', line 14

def user
  @user
end

Instance Method Details

#connect ⇒ Object 



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# File 'lib/bolt/transport/ssh/connection.rb', line 47

def connect
  options = {
    logger: @transport_logger,
    non_interactive: true
  }

  if (key = target.options['private-key'])
    if key.instance_of?(String)
      options[:keys] = key
    else
      options[:key_data] = [key['key-data']]
    end
  end

  options[:port] = target.port if target.port
  options[:password] = target.password if target.password
  # Support both net-ssh 4 and 5. We use 5 in packaging, but Beaker pins to 4 so we
  # want the gem to be compatible with version 4.
  options[:verify_host_key] = if target.options['host-key-check'].nil?
                                # Fall back to SSH behavior. This variable will only be set in net-ssh 5.3+.
                                if @strict_host_key_checking.nil? || @strict_host_key_checking
                                  net_ssh_verifier(:always)
                                else
                                  # SSH's behavior with StrictHostKeyChecking=no: adds new keys to known_hosts.
                                  # If known_hosts points to /dev/null, then equivalent to :never where it
                                  # accepts any key beacuse they're all new.
                                  net_ssh_verifier(:accept_new_or_tunnel_local)
                                end
                              elsif target.options['host-key-check']
                                net_ssh_verifier(:always)
                              else
                                net_ssh_verifier(:never)
                              end
  options[:timeout] = target.options['connect-timeout'] if target.options['connect-timeout']

  options[:proxy] = Net::SSH::Proxy::Jump.new(target.options['proxyjump']) if target.options['proxyjump']

  # This option was to address discrepency betwen net-ssh host-key-check and ssh(1)
  # For the net-ssh 5.x series it defaults to true, in 6.x it will default to false, and will be removed in 7.x
  # https://github.com/net-ssh/net-ssh/pull/663#issuecomment-469979931
  options[:check_host_ip] = false if Net::SSH::VALID_OPTIONS.include?(:check_host_ip)

  if @load_config
    # Mirroring:
    # https://github.com/net-ssh/net-ssh/blob/master/lib/net/ssh/authentication/agent.rb#L80
    # https://github.com/net-ssh/net-ssh/blob/master/lib/net/ssh/authentication/pageant.rb#L403
    if defined?(UNIXSocket) && UNIXSocket
      if ENV['SSH_AUTH_SOCK'].to_s.empty?
        @logger.debug { "Disabling use_agent in net-ssh: ssh-agent is not available" }
        options[:use_agent] = false
      end
    elsif Bolt::Util.windows?
      require 'Win32API' # case matters in this require!
      # https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-findwindoww
      @find_window ||= Win32API.new('user32', 'FindWindowW', %w[P P], 'L')
      if @find_window.call(nil, PAGEANT_NAME).to_i == 0
        @logger.debug { "Disabling use_agent in net-ssh: pageant process not running" }
        options[:use_agent] = false
      end
    end
  else
    # Disable ssh config and ssh-agent if requested via load_config
    options[:config] = false
    options[:use_agent] = false
  end

  @session = Net::SSH.start(target.host, @user, options)
  @logger.debug { "Opened session" }
rescue Net::SSH::AuthenticationFailed => e
  raise Bolt::Node::ConnectError.new(
    e.message,
    'AUTH_ERROR'
  )
rescue Net::SSH::HostKeyError => e
  raise Bolt::Node::ConnectError.new(
    "Host key verification failed for #{target.uri}: #{e.message}",
    'HOST_KEY_ERROR'
  )
rescue Net::SSH::ConnectionTimeout
  raise Bolt::Node::ConnectError.new(
    "Timeout after #{target.options['connect-timeout']} seconds connecting to #{target.uri}",
    'CONNECT_ERROR'
  )
rescue StandardError => e
  raise Bolt::Node::ConnectError.new(
    "Failed to connect to #{target.uri}: #{e.message}",
    'CONNECT_ERROR'
  )
end

#copy_file(source, destination) ⇒ Object 



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# File 'lib/bolt/transport/ssh/connection.rb', line 263

def copy_file(source, destination)
  @session.scp.upload!(source, destination, recursive: true)
rescue StandardError => e
  raise Bolt::Node::FileError.new(e.message, 'WRITE_ERROR')
end

#disconnect ⇒ Object 



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# File 'lib/bolt/transport/ssh/connection.rb', line 137

def disconnect
  if @session && !@session.closed?
    begin
      Timeout.timeout(@target.options['disconnect-timeout']) { @session.close }
    rescue Timeout::Error
      @session.shutdown!
    end
    @logger.debug { "Closed session" }
  end
end

#execute(command, sudoable: false, **options) ⇒ Object 



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# File 'lib/bolt/transport/ssh/connection.rb', line 184

def execute(command, sudoable: false, **options)
  result_output = Bolt::Node::Output.new
  run_as = options[:run_as] || self.run_as
  escalate = sudoable && run_as && @user != run_as
  use_sudo = escalate && @target.options['run-as-command'].nil?

  command_str = inject_interpreter(options[:interpreter], command)

  if escalate
    if use_sudo
      sudo_flags = ["sudo", "-S", "-u", run_as, "-p", Sudoable.sudo_prompt]
      sudo_flags += ["-E"] if options[:environment]
      sudo_str = Shellwords.shelljoin(sudo_flags)
    else
      sudo_str = Shellwords.shelljoin(@target.options['run-as-command'] + [run_as])
    end
    command_str = build_sudoable_command_str(command_str, sudo_str, @sudo_id, options)
  end

  # Including the environment declarations in the shelljoin will escape
  # the = sign, so we have to handle them separately.
  if options[:environment]
    env_decls = options[:environment].map do |env, val|
      "#{env}=#{Shellwords.shellescape(val)}"
    end
    command_str = "#{env_decls.join(' ')} #{command_str}"
  end

  @logger.debug { "Executing: #{command_str}" }

  session_channel = @session.open_channel do |channel|
    # Request a pseudo tty
    channel.request_pty if target.options['tty']

    channel.exec(command_str) do |_, success|
      unless success
        raise Bolt::Node::ConnectError.new(
          "Could not execute command: #{command_str.inspect}",
          'EXEC_ERROR'
        )
      end

      channel.on_data do |_, data|
        unless use_sudo && handled_sudo(channel, data, options[:stdin])
          result_output.stdout << data
        end
        @logger.debug { "stdout: #{data.strip}" }
      end

      channel.on_extended_data do |_, _, data|
        unless use_sudo && handled_sudo(channel, data, options[:stdin])
          result_output.stderr << data
        end
        @logger.debug { "stderr: #{data.strip}" }
      end

      channel.on_request("exit-status") do |_, data|
        result_output.exit_code = data.read_long
      end
      # A wrapper is used to direct stdin when elevating privilage or using tty
      if options[:stdin] && !use_sudo && !options[:wrapper]
        channel.send_data(options[:stdin])
        channel.eof!
      end
    end
  end
  session_channel.wait

  if result_output.exit_code == 0
    @logger.debug { "Command returned successfully" }
  else
    @logger.info { "Command failed with exit code #{result_output.exit_code}" }
  end
  result_output
rescue StandardError
  @logger.debug { "Command aborted" }
  raise
end

#handled_sudo(channel, data, stdin) ⇒ Object 



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# File 'lib/bolt/transport/ssh/connection.rb', line 148

def handled_sudo(channel, data, stdin)
  if data.lines.include?(Sudoable.sudo_prompt)
    if target.options['sudo-password']
      channel.send_data("#{target.options['sudo-password']}\n")
      channel.wait
      return true
    else
      # Cancel the sudo prompt to prevent later commands getting stuck
      channel.close
      raise Bolt::Node::EscalateError.new(
        "Sudo password for user #{@user} was not provided for #{target.uri}",
        'NO_PASSWORD'
      )
    end
  elsif data =~ /^#{@sudo_id}/
    if stdin
      channel.send_data(stdin)
      channel.eof!
    end
    return true
  elsif data =~ /^#{@user} is not in the sudoers file\./
    @logger.debug { data }
    raise Bolt::Node::EscalateError.new(
      "User #{@user} does not have sudo permission on #{target.uri}",
      'SUDO_DENIED'
    )
  elsif data =~ /^Sorry, try again\./
    @logger.debug { data }
    raise Bolt::Node::EscalateError.new(
      "Sudo password for user #{@user} not recognized on #{target.uri}",
      'BAD_PASSWORD'
    )
  end
  false
end

#net_ssh_verifier(verifier) ⇒ Object

This handles renaming Net::SSH verifiers between version 4.x and 5.x of the gem



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# File 'lib/bolt/transport/ssh/connection.rb', line 278

def net_ssh_verifier(verifier)
  case verifier
  when :always
    if defined?(Net::SSH::Verifiers::Always)
      Net::SSH::Verifiers::Always.new
    else
      Net::SSH::Verifiers::Secure.new
    end
  when :never
    if defined?(Net::SSH::Verifiers::Never)
      Net::SSH::Verifiers::Never.new
    else
      Net::SSH::Verifiers::Null.new
    end
  when :accept_new_or_tunnel_local
    if defined?(Net::SSH::Verifiers::AcceptNewOrLocalTunnel)
      Net::SSH::Verifiers::AcceptNewOrLocalTunnel.new
    else
      Net::SSH::Verifiers::Lenient.new
    end
  end
end

#write_executable_from_content(dest, content, filename) ⇒ Object 



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# File 'lib/bolt/transport/ssh/connection.rb', line 269

def write_executable_from_content(dest, content, filename)
  remote_path = File.join(dest.to_s, filename)
  @session.scp.upload!(StringIO.new(content), remote_path)
  make_executable(remote_path)
  remote_path
end