Class: Msf::Sessions::WinrmCommandShell::WinRMStreamAdapter

Inherits:
Object
  • Object
show all
Defined in:
lib/msf/base/sessions/winrm_command_shell.rb

Overview

Abstract WinRM to look like a stream so CommandShell can be happy

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(shell, interactive_command_id, on_shell_ended) ⇒ WinRMStreamAdapter

Returns a new instance of WinRMStreamAdapter.

Parameters:

  • shell (Net::MsfWinRM::StdinShell)

    Shell for talking to the WinRM service

  • on_shell_ended (Method)

    Callback for when the background thread notices the shell has ended



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 17

def initialize(shell, interactive_command_id, on_shell_ended)
  # To buffer input received while a session is backgrounded, we stick responses in a list
  @buffer_mutex = Mutex.new
  @buffer = []
  @check_stdin_event = Rex::Sync::Event.new(false, true)
  @received_stdout_event = Rex::Sync::Event.new(false, true)
  self.interactive_command_id = interactive_command_id
  self.shell = shell
  self.on_shell_ended = on_shell_ended
end

Instance Attribute Details

#interactive_command_idObject

rubocop:enable Lint/SuppressedException



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 156

def interactive_command_id
  @interactive_command_id
end

#keep_alive_threadObject

rubocop:enable Lint/SuppressedException



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 156

def keep_alive_thread
  @keep_alive_thread
end

#on_shell_endedObject

rubocop:enable Lint/SuppressedException



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 156

def on_shell_ended
  @on_shell_ended
end

#shellObject

rubocop:enable Lint/SuppressedException



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 156

def shell
  @shell
end

Instance Method Details

#_get_once(length) ⇒ Object



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 74

def _get_once(length)
  result = ''
  @buffer_mutex.synchronize do
    result = @buffer.join('')
    @buffer = []
    if (length > -1) && (result.length > length)
      # Return up to length, and keep the rest in the buffer
      extra = result[length..-1]
      result = result[0, length]
      @buffer << extra
    end
  end
  result
end

#closeObject

Close the shell; cleanly terminating it on the server if possible

The shell may already be dead, or unreachable at this point, so do a best effort, and capture exceptions rubocop:disable Lint/SuppressedException



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 149

def close
  stop_keep_alive_loop
  shell.cleanup_command(interactive_command_id)
rescue WinRM::WinRMWSManFault
end

#get_once(length = -1,, timeout = 1) ⇒ Object

:category: Msf::Session::Provider::SingleCommandShell implementors

Read from the command shell.



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 51

def get_once(length = -1, timeout = 1)
  start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC, :millisecond)
  result = ''
  loop do
    result = _get_once(length)
    time = Process.clock_gettime(Process::CLOCK_MONOTONIC, :millisecond)
    elapsed = time - start_time
    time_remaining = timeout - elapsed
    break if (result != '' || time_remaining <= 0)

    # rubocop:disable Lint/SuppressedException
    begin
      # We didn't receive anything - let's wait for some more
      @received_stdout_event.wait(time_remaining)
    rescue TimeoutError
    end
    # rubocop:enable Lint/SuppressedException
    # If we didn't get anything, let's hurry the background thread along
    refresh_stdout unless result
  end
  result
end

#localinfoObject



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 32

def localinfo
  shell.transport.localinfo
end

#peerinfoObject



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 28

def peerinfo
  shell.transport.peerinfo
end

#refresh_stdoutObject

Trigger the background thread to go get more stdout



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 37

def refresh_stdout
  @check_stdin_event.set
end

#start_keep_alive_loop(framework) ⇒ Object

Start a background thread for regularly checking for stdout



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 90

def start_keep_alive_loop(framework)
  self.keep_alive_thread = framework.threads.spawn('WinRM-shell-keepalive', false, shell) do |_thr_shell|
    loop_delay = 0.5
    loop do
      tmp_buffer = []
      output_seen = false
      shell.read_stdout(interactive_command_id) do |stdout, stderr|
        if stdout || stderr
          output_seen = true
        end
        tmp_buffer << stdout if stdout
        tmp_buffer << stderr if stderr
      end
      @buffer_mutex.synchronize do
        @buffer.concat(tmp_buffer)
      end

      # If our last request received stdout, let's be ready for some more
      if output_seen
        @received_stdout_event.set
        loop_delay = 0.5
      else
        # Gradual backoff
        loop_delay *= 4
        loop_delay = [loop_delay, 30].min
      end

      # Wait loop_delay seconds, or until an interactive thread wakes us up
      begin
        @check_stdin_event.wait(loop_delay)
        # rubocop:disable Lint/SuppressedException
      rescue TimeoutError
      end
      # rubocop:enable Lint/SuppressedException
      Thread.pass
    rescue WinRM::WinRMWSManFault => e
      print_error(e.fault_description)
      on_shell_ended.call
    rescue EOFError
      # Shell has been terminated
      on_shell_ended.call
    rescue Rex::HostUnreachable => e
      on_shell_ended.call(e.message)
    rescue StandardError => e
      on_shell_ended.call(e.message)
    end
  end
end

#stop_keep_alive_loopObject

Stop the background thread



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 140

def stop_keep_alive_loop
  keep_alive_thread.kill
end

#write(buf) ⇒ Object



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# File 'lib/msf/base/sessions/winrm_command_shell.rb', line 41

def write(buf)
  shell.send_stdin(buf, interactive_command_id)
  refresh_stdout
end