Class: SshConnection

Inherits:
Object
  • Object
show all
Defined in:
lib/audit/lib/connection/ssh_connection.rb

Direct Known Subclasses

AmiConnection

Constant Summary collapse

@@logger = 
Logger.new(STDOUT)

Instance Method Summary collapse

Constructor Details

#initialize(parameters) ⇒ SshConnection

Returns a new instance of SshConnection.



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 9

def initialize(parameters)
	raise "Need parameter :connection_params" unless parameters[:connection_params]
	
	if parameters[:logger] then
		@@logger = parameters[:logger]
	end

	@parameters = parameters[:connection_params]
	@parameters[:user] = 'root' unless @parameters[:user]
	raise "No target host specified" unless @parameters[:host]
end

Instance Method Details

#<<(command) ⇒ Object 



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 73

def <<(command)
	exec(command)
end

#abort ⇒ Object

force the connection to close



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 241

def abort()
  if @ssh_session && !@ssh_session.closed? then
    #try to close connection gracefully
    @ssh_session.close
    # and if it won't, send out the hunter to bring in Snowwhite's heart after some time
    Thread.new do
      sleep 5
      @ssh_session.shutdown! unless @ssh_session.nil? || @ssh_session.closed?
    end
  end
end

#close ⇒ Object 



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 69

def close
	@ssh_session.close
end

#closed? ⇒ Boolean

if the connection is closed

Returns:

  • (Boolean) 


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# File 'lib/audit/lib/connection/ssh_connection.rb', line 222

def closed?
	return @ssh_session.nil? || @ssh_session.closed?
end

#copy_from_remote(remote_file, local_path) ⇒ Object

copy remote file to local path



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 175

def copy_from_remote(remote_file, local_path)
	begin
		@@logger.info { "Copying file from #{remote_file} to #{local_path}" }
		@ssh_session.scp.download!(remote_file, local_path)
		return true
	rescue => err
		@@logger.error { "SCP failed: #{err.message}" }
		@@logger.error { "\t #{err.backtrace}" }
	end
end

#copy_to_remote(local_file, remote_path) ⇒ Object

copy local file to remote path



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 170

def copy_to_remote(local_file, remote_path)
	@ssh_session.scp.upload! local_file, remote_path
end

#delete_remote(remote_file) ⇒ Object

delete remote file



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 196

def delete_remote(remote_file)
	exec("rm #{remote_file}")
end

#exec(command, stdin = nil) ⇒ Object

remote execute a command



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 78

def exec(command, stdin = nil)
  exit_status = 0 # define variable so that it will be available in the block at method scope
  @ssh_session.open_channel do |ch|
    @@logger.info("Executing command '#{command}'")
    ch.exec(command) do|ch, success|

             if success then
        @@logger.debug("Command sucessfully executed")
               ch.on_data() do|ch, data|
                 #process_stdout(data) unless data
                 @stdout_handler.call(data) unless @stdout_handler.nil? or data.nil?
               end
               ch.on_extended_data() do|ch, type, data|
                 @stderr_handler.call(data) unless @stderr_handler.nil? or data.nil?
               end
               ch.on_request "exit-status" do|ch, data|
                 exit_status = data.read_long unless data.nil?
               end
               ch.on_close do |ch|
                 @close_handler.call() unless @close_handler.nil?
               end
               ch.on_eof do |ch|
                 @close_handler.call() unless @close_handler.nil?
               end

               ch.send_data stdin if stdin
             else
        @@logger.debug("")
               exit_status = 127
             end
           end
    ch.wait
  end

  return exit_status
end

#exec_new(command, stdin = nil) ⇒ Object

XXX: new remote execute a command



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 116

def exec_new(command, stdin = nil)
  exit_status = 0 # define variable so that it will be available in the block at method scope
  channel = @ssh_session.open_channel do |ch|
    ch.exec(command) do|ch, success|

           if success then
        @@logger.info("SshConnection: starts executing '#{command}'")
               ch.on_data() do|ch, data|
                 #process_stdout(data) unless data
                 @stdout_handler.call(data) unless @stdout_handler.nil? or data.nil?
               end
               ch.on_extended_data() do|ch, type, data|
                 @stderr_handler.call(data) unless @stderr_handler.nil? or data.nil?
               end
               ch.on_request "exit-status" do|ch, data|
                 exit_status = data.read_long unless data.nil?
          @@logger.info("SshConnection.on_request: process terminated with exit-status: #{exit_status}")
          if exit_status != 0
            @@logger.error("SshConnection.on_request: Remote command execution failed with code: #{exit_status}")
          end
               end
        ch.on_request "exit-signal" do |ch, data|
          @@logger.info("SshConnection.on_request: process terminated with exit-signal: #{data.read_string}")
        end
               ch.on_close do |ch|
          @@logger.info("SshConnection.on_close: remote end is closing!")
                 #@close_handler.call() unless @close_handler.nil?
               end
               ch.on_eof do |ch|
          @@logger.info("SshConnection.on_eof: remote end is done sending data")
                 #@close_handler.call() unless @close_handler.nil?
               end
        ch.on_open_failed do |ch, code, desc|
          @@logger.info("SshConnection.on_open_failed: code=#{code} desc=#{desc}")
        end
        ch.on_process do |ch|
          #@@logger.debug("SshConnection.on_process; send line-feed/sleep")
          ch.send_data("\n")
        end

               #ch.send_data stdin if stdin
           else
        @@logger.debug("SshConnection: the remote command could not be invoked!")
               exit_status = 127
             end
           end
    #ch.wait
  end
  channel.wait
  return exit_status
end

#move_from_remote(remote_file, local_path) ⇒ Object

copies remote file to local path and deletes remote file afterwards



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 201

def move_from_remote(remote_file, local_path)
	copy_from_remote(remote_file, local_path)
	delete_remote(remote_file)
end

#on_close(&block) ⇒ Object

hook a handler who is called on connection close



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 217

def on_close(&block)
	@close_handler = block
end

#on_stderr(&block) ⇒ Object

hook a handler who is called on text on stderr



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 212

def on_stderr(&block)
	@stderr_handler = block
end

#on_stdout(&block) ⇒ Object

hook a handler who is called on text on stdout.



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 207

def on_stdout(&block)
	@stdout_handler = block
end

#open(&block) ⇒ Object

open the ssh connection to the remote host



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 22

def open(&block)
	if @ssh_session && !@ssh_session.closed? then
		@@logger.warn("trying to open an already opened ssh connection")
		raise "trying to open an already opened ssh connection"
	end
	
	@@logger.info("opening ssh connection with parameters: " + @parameters.to_s)

	parameters = @parameters.clone()
	host = @parameters[:host]
	user = @parameters[:user]
	
	parameters.delete(:host)
	parameters.delete(:user)
	
	if @parameters[:keys] then
		@@logger.info("Starting SSH session with public key authentication")
	elsif @parameters[:key_data] then
		@@logger.info("Starting SSH session with public key authentication")
	elsif @parameters[:password] then
		@@logger.info("Starting SSH session with password authentication")
	else
		@@logger.error("No SSH authentication method found in parameters")
		raise "No authentication method found"
	end

	connected = false
	trials = 5
	while !connected and trials > 0
		begin
			@ssh_session = Net::SSH.start(host, user, parameters)
			connected = true
		rescue Exception => e
			@@logger.warn("connection attempt failed due to #{e.backtrace}")
		end
		trials -= 1
		if !connected
			sleep(20)
		end
	end

	if block then
		yield self
		close
	end
end

#to_hash ⇒ Object 



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 231

def to_hash()
  return {
    :type => :CONNECTION,
    :subtype => :ssh,
    :user => @parameters[:user],
    :host => @parameters[:host]
  }
end

#to_s ⇒ Object

return a string representation of the connection



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 227

def to_s()
  return "ssh:#{@parameters[:user]}@#{@parameters[:host]}"
end

#write_to_remote_file(string, remote_path) ⇒ Object

write a string to a remote file



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# File 'lib/audit/lib/connection/ssh_connection.rb', line 187

def write_to_remote_file(string, remote_path)
  #filename = "/tmp/" + Random.srand().to_s() + ".sh"
  filename = "/tmp/" + Kernel::srand().to_s() + ".sh"
  File.open(filename, 'w') {|f| f.write(string)}
  copy_to_remote(filename, remote_path)
  File.delete(filename)
end