Class: Pwnlib::Tubes::Tube

Inherits:
Object
  • Object
show all
Includes:
Context, Logger
Defined in:
lib/pwnlib/tubes/tube.rb

Overview

Things common to all tubes (sockets, tty, …)

Direct Known Subclasses

Process, SerialTube, Sock

Constant Summary collapse

BUFSIZE =

Receive 4096 bytes each time.

4096

Instance Method Summary collapse

Constructor Details

#initialize(timeout: nil) ⇒ Tube

Instantiate a Pwnlib::Tubes::Tube object.

Parameters:

  • timeout (Float) (defaults to: nil) —

    Any positive floating number, indicates timeout in seconds. Using context.timeout if timeout equals to nil.


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# File 'lib/pwnlib/tubes/tube.rb', line 43

def initialize(timeout: nil)
  @timer = Timer.new(timeout)
  @buffer = Buffer.new
end

Instance Method Details

#gets(sep = context.newline, drop: false, timeout: nil) ⇒ String

Receives the next “line” from the tube; lines are separated by sep. The difference with IO#gets is using context.newline as default newline.

Examples:

Sock.new('127.0.0.1', 1337).gets
#=> "This is line one\n"

Sock.new('127.0.0.1', 1337).gets(drop: true)
#=> "This is line one"

Sock.new('127.0.0.1', 1337).gets 'line'
#=> "This is line"

Sock.new('127.0.0.1', 1337).gets ''
#=> "This is line"

Sock.new('127.0.0.1', 1337).gets(4)
#=> "This"

Parameters:

  • sep (String, Integer) (defaults to: context.newline) —

    If String is given, use sep as the separator. If Integer is given, receive exactly sep bytes.

  • drop (Boolean) (defaults to: false) —

    Whether drop the ending.

  • timeout (Float) (defaults to: nil) —

    Any positive floating number, indicates timeout in seconds. Using context.timeout if timeout equals to nil.

Returns:

  • (String) —

    The next "line".

Raises:


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# File 'lib/pwnlib/tubes/tube.rb', line 250

def gets(sep = context.newline, drop: false, timeout: nil)
  case sep
  when Integer
    recvn(sep, timeout: timeout)
  when String
    recvuntil(sep, drop: drop, timeout: timeout)
  else
    raise ArgumentError, 'only Integer and String are supported'
  end
end

#interact ⇒ Object

Does simultaneous reading and writing to the tube. In principle this just connects the tube to standard in and standard out.


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# File 'lib/pwnlib/tubes/tube.rb', line 357

def interact
  log.info('Switching to interactive mode')
  $stdout.write(@buffer.get)
  until io_out.closed?
    rs, = IO.select([$stdin, io_out])
    if rs.include?($stdin)
      s = $stdin.readpartial(BUFSIZE)
      write(s)
    end
    if rs.include?(io_out)
      s = recv
      $stdout.write(s)
    end
  end
rescue ::Pwnlib::Errors::EndOfTubeError
  log.info('Got EOF in interactive mode')
end

#puts(*objs) ⇒ Integer

Sends the given object(s). The difference with IO#puts is using context.newline as default newline.

Examples:

s.puts
puts client.recv
#
#=> nil

s.puts('shik', "hao\n", 123)
puts client.recv
# shik
# hao
# 123
#=> nil

s.puts(["darkhh\n\n", 'wei shi', 360])
puts client.recv
# darkhh
#
# wei shi
# 360
#=> nil

Parameters:

  • objs (Array<Object>) —

    The objects to be sent.

Returns:

  • (Integer) —

    Returns the number of bytes had been sent.


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# File 'lib/pwnlib/tubes/tube.rb', line 343

def puts(*objs)
  return write(context.newline) if objs.empty?

  objs = *objs.flatten
  s = +''
  objs.map(&:to_s).each do |elem|
    s << elem
    s << context.newline unless elem.end_with?(context.newline)
  end
  write(s)
end

#recv(num_bytes = nil, timeout: nil) ⇒ String Also known as: read

Receives up to num_bytes bytes of data from the tube, and returns as soon as any quantity of data is available.

Parameters:

  • num_bytes (Integer) (defaults to: nil) —

    The maximum number of bytes to receive.

  • timeout (Float) (defaults to: nil) —

    Any positive floating number, indicates timeout in seconds. Using context.timeout if timeout equals to nil.

Returns:

  • (String) —

    A string contains bytes received from the tube, or '' if a timeout occurred while waiting.

Raises:


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# File 'lib/pwnlib/tubes/tube.rb', line 61

def recv(num_bytes = nil, timeout: nil)
  return '' if @buffer.empty? && !fillbuffer(timeout: timeout)

  @buffer.get(num_bytes)
end

#recvall(timeout: nil) ⇒ String Also known as: readall

Receives data until reaching EOF or a timeout is occurred.

Parameters:

  • timeout (Float) (defaults to: nil) —

    Any positive floating number, indicates timeout in seconds. Using context.timeout if timeout equals to nil.

Returns:

  • (String) —

    Returns the data received.


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# File 'lib/pwnlib/tubes/tube.rb', line 280

def recvall(timeout: nil)
  recvn(1 << 63, timeout: timeout)
rescue ::Pwnlib::Errors::EndOfTubeError, ::Pwnlib::Errors::TimeoutError
  @buffer.get
end

#recvline(drop: false, timeout: nil) ⇒ String

Receives a single line from the tube. A “line” is any sequence of bytes terminated by the byte sequence set in context.newline, which defaults to “\n”.

Parameters:

  • drop (Boolean) (defaults to: false) —

    Whether drop the ending.

  • timeout (Float) (defaults to: nil) —

    Any positive floating number, indicates timeout in seconds. Using context.timeout if timeout equals to nil.

Returns:

  • (String) —

    All bytes received over the tube until the first newline is received. Optionally retains the ending.


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# File 'lib/pwnlib/tubes/tube.rb', line 215

def recvline(drop: false, timeout: nil)
  recvuntil(context.newline, drop: drop, timeout: timeout)
end

#recvn(num_bytes, timeout: nil) ⇒ String Also known as: readn

Receives exactly num_bytes bytes. If the request is not satisfied before timeout seconds pass, all data is buffered and an empty string '' is returned.

Parameters:

  • num_bytes (Integer) —

    The number of bytes to receive.

  • timeout (Float) (defaults to: nil) —

    Any positive floating number, indicates timeout in seconds. Using context.timeout if timeout equals to nil.

Returns:

  • (String) —

    A string contains bytes received from the tube, or '' if a timeout occurred while waiting.

Raises:


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# File 'lib/pwnlib/tubes/tube.rb', line 138

def recvn(num_bytes, timeout: nil)
  @timer.countdown(timeout) do
    fillbuffer while @timer.active? && @buffer.size < num_bytes
    @buffer.size >= num_bytes ? @buffer.get(num_bytes) : ''
  end
end

#recvpred(timeout: nil) {|data| ... } ⇒ String

Receives one byte at a time from the tube, until the predicate evaluates to true.

Parameters:

  • timeout (Float) (defaults to: nil) —

    Any positive floating number, indicates timeout in seconds. Using context.timeout if timeout equals to nil.

Yields:

  • A predicate to evaluate whether the data satisfy the condition.

Yield Parameters:

  • data (String) —

    A string data to be validated by the predicate.

Yield Returns:

  • (Boolean) —

    Whether the data satisfy the condition.

Returns:

  • (String) —

    A string contains bytes received from the tube, or '' if a timeout occurred while waiting.

Raises:


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# File 'lib/pwnlib/tubes/tube.rb', line 102

def recvpred(timeout: nil)
  raise ArgumentError, 'Need a block for recvpred' unless block_given?

  @timer.countdown(timeout) do
    data = +''
    begin
      until yield(data)
        return '' unless @timer.active?

        c = recv(1)

        return '' if c.empty?

        data << c
      end
      data.slice!(0..-1)
    ensure
      unrecv(data)
    end
  end
end

#recvregex(regex, timeout: nil) ⇒ String

Wrapper around recvpred, which will return when a regex matches the string in the buffer.

Parameters:

  • regex (Regexp) —

    A regex to match.

  • timeout (Float) (defaults to: nil) —

    Any positive floating number, indicates timeout in seconds. Using context.timeout if timeout equals to nil.

Returns:

  • (String) —

    A string contains bytes received from the tube, or '' if a timeout occurred while waiting.


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# File 'lib/pwnlib/tubes/tube.rb', line 270

def recvregex(regex, timeout: nil)
  recvpred(timeout: timeout) { |data| data =~ regex }
end

#recvuntil(delims, drop: false, timeout: nil) ⇒ String

Receives data until one of delims is encountered. If the request is not satisfied before timeout seconds pass, all data is buffered and an empty string is returned.

Parameters:

  • delims (Array<String>) —

    String of delimiters characters, or list of delimiter strings.

  • drop (Boolean) (defaults to: false) —

    Whether drop the ending.

  • timeout (Float) (defaults to: nil) —

    Any positive floating number, indicates timeout in seconds. Using context.timeout if timeout equals to nil.

Returns:

  • (String) —

    A string contains bytes, which ends string in delims, received from the tube.

Raises:

Difference with Python pwntools:

  • We return the string that ends the earliest, rather then starts the earliest, since the latter can't be done greedly. Still, it would be bad to call this for case with ambiguity.


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# File 'lib/pwnlib/tubes/tube.rb', line 163

def recvuntil(delims, drop: false, timeout: nil)
  delims = Array(delims)
  max_len = delims.map(&:size).max
  @timer.countdown(timeout) do
    data = Buffer.new
    matching = +''
    begin
      while @timer.active?
        s = recv(1)

        return '' if s.empty?

        matching << s

        sidx = matching.size
        match_len = 0
        delims.each do |d|
          idx = matching.index(d)
          next unless idx

          if idx + d.size <= sidx + match_len
            sidx = idx
            match_len = d.size
          end
        end

        if sidx < matching.size
          r = data.get + matching.slice!(0, sidx + match_len)
          r.slice!(-match_len..-1) if drop
          return r
        end

        data << matching.slice!(0...-max_len) if matching.size > max_len
      end
      ''
    ensure
      unrecv(matching)
      unrecv(data)
    end
  end
end

#send(data) ⇒ Integer Also known as: write

Sends data.

Parameters:

  • data (String) —

    The data string to be sent.

Returns:

  • (Integer) —

    Returns the number of bytes had been sent.


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# File 'lib/pwnlib/tubes/tube.rb', line 293

def send(data)
  data = data.to_s
  log.debug(format('Sent %#x bytes:', data.size))
  log.indented(::Pwnlib::Util::HexDump.hexdump(data), level: DEBUG)
  send_raw(data)
  data.size
end

#sendline(obj) ⇒ Integer

Sends the given object with context.newline.

Parameters:

  • obj (Object) —

    The object to be sent.

Returns:

  • (Integer) —

    Returns the number of bytes had been sent.


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# File 'lib/pwnlib/tubes/tube.rb', line 308

def sendline(obj)
  s = obj.to_s + context.newline
  write(s)
end

#unrecv(data) ⇒ Integer

Puts the specified data back at the beginning of the receive buffer.

Parameters:

  • data (String) —

    A string to put back.

Returns:

  • (Integer) —

    The length of the put back data.


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# File 'lib/pwnlib/tubes/tube.rb', line 75

def unrecv(data)
  @buffer.unget(data)
  data.size
end