metasploit-framework/lib/rex/post/meterpreter/packet.rb

# -*- coding: binary -*-

module Rex
module Post
module Meterpreter

#
# Constants
#
PACKET_TYPE_REQUEST         = 0
PACKET_TYPE_RESPONSE        = 1
PACKET_TYPE_PLAIN_REQUEST   = 10
PACKET_TYPE_PLAIN_RESPONSE  = 11

#
# TLV Meta Types
#
TLV_META_TYPE_NONE          = 0
TLV_META_TYPE_STRING        = (1 << 16)
TLV_META_TYPE_UINT          = (1 << 17)
TLV_META_TYPE_RAW           = (1 << 18)
TLV_META_TYPE_BOOL          = (1 << 19)
TLV_META_TYPE_QWORD         = (1 << 20)
TLV_META_TYPE_COMPRESSED    = (1 << 29)
TLV_META_TYPE_GROUP         = (1 << 30)
TLV_META_TYPE_COMPLEX       = (1 << 31)

# Exclude compressed from the mask since other meta types (e.g. RAW) can also
# be compressed
TLV_META_MASK = (
  TLV_META_TYPE_STRING |
  TLV_META_TYPE_UINT |
  TLV_META_TYPE_RAW |
  TLV_META_TYPE_BOOL |
  TLV_META_TYPE_QWORD |
  TLV_META_TYPE_GROUP |
  TLV_META_TYPE_COMPLEX
)

#
# TLV base starting points
#
TLV_RESERVED                = 0
TLV_EXTENSIONS              = 20000
TLV_USER                    = 40000
TLV_TEMP                    = 60000

#
# TLV Specific Types
#
TLV_TYPE_ANY                = TLV_META_TYPE_NONE   |   0
TLV_TYPE_METHOD             = TLV_META_TYPE_STRING |   1
TLV_TYPE_REQUEST_ID         = TLV_META_TYPE_STRING |   2
TLV_TYPE_EXCEPTION          = TLV_META_TYPE_GROUP  |   3
TLV_TYPE_RESULT             = TLV_META_TYPE_UINT   |   4


TLV_TYPE_STRING             = TLV_META_TYPE_STRING |  10
TLV_TYPE_UINT               = TLV_META_TYPE_UINT   |  11
TLV_TYPE_BOOL               = TLV_META_TYPE_BOOL   |  12

TLV_TYPE_LENGTH             = TLV_META_TYPE_UINT   |  25
TLV_TYPE_DATA               = TLV_META_TYPE_RAW    |  26
TLV_TYPE_FLAGS              = TLV_META_TYPE_UINT   |  27

TLV_TYPE_CHANNEL_ID         = TLV_META_TYPE_UINT   |  50
TLV_TYPE_CHANNEL_TYPE       = TLV_META_TYPE_STRING |  51
TLV_TYPE_CHANNEL_DATA       = TLV_META_TYPE_RAW    |  52
TLV_TYPE_CHANNEL_DATA_GROUP = TLV_META_TYPE_GROUP  |  53
TLV_TYPE_CHANNEL_CLASS      = TLV_META_TYPE_UINT   |  54
TLV_TYPE_CHANNEL_PARENTID   = TLV_META_TYPE_UINT   |  55

TLV_TYPE_SEEK_WHENCE        = TLV_META_TYPE_UINT   |  70
TLV_TYPE_SEEK_OFFSET        = TLV_META_TYPE_UINT   |  71
TLV_TYPE_SEEK_POS           = TLV_META_TYPE_UINT   |  72

TLV_TYPE_EXCEPTION_CODE     = TLV_META_TYPE_UINT   | 300
TLV_TYPE_EXCEPTION_STRING   = TLV_META_TYPE_STRING | 301

TLV_TYPE_LIBRARY_PATH       = TLV_META_TYPE_STRING | 400
TLV_TYPE_TARGET_PATH        = TLV_META_TYPE_STRING | 401
TLV_TYPE_MIGRATE_PID        = TLV_META_TYPE_UINT   | 402
TLV_TYPE_MIGRATE_LEN        = TLV_META_TYPE_UINT   | 403
TLV_TYPE_MIGRATE_PAYLOAD    = TLV_META_TYPE_STRING | 404
TLV_TYPE_MIGRATE_ARCH       = TLV_META_TYPE_UINT   | 405

TLV_TYPE_CIPHER_NAME        = TLV_META_TYPE_STRING | 500
TLV_TYPE_CIPHER_PARAMETERS  = TLV_META_TYPE_GROUP  | 501

#
# Core flags
#
LOAD_LIBRARY_FLAG_ON_DISK   = (1 << 0)
LOAD_LIBRARY_FLAG_EXTENSION = (1 << 1)
LOAD_LIBRARY_FLAG_LOCAL     = (1 << 2)

###
#
# Base TLV (Type-Length-Value) class
#
###
class Tlv
  attr_accessor :type, :value, :compress

  ##
  #
  # Constructor
  #
  ##

  #
  # Returns an instance of a TLV.
  #
  def initialize(type, value = nil, compress=false)
    @type     = type
    @compress = compress

    if (value != nil)
      if (type & TLV_META_TYPE_STRING == TLV_META_TYPE_STRING)
        if (value.kind_of?(Fixnum))
          @value = value.to_s
        else
          @value = value.dup
        end
      else
        @value = value
      end
    end
  end

  def inspect
    utype = type ^ TLV_META_TYPE_COMPRESSED
    group = false
    meta = case (utype & TLV_META_MASK)
      when TLV_META_TYPE_STRING; "STRING"
      when TLV_META_TYPE_UINT; "INT"
      when TLV_META_TYPE_RAW; "RAW"
      when TLV_META_TYPE_BOOL; "BOOL"
      when TLV_META_TYPE_QWORD; "QWORD"
      when TLV_META_TYPE_GROUP; group=true; "GROUP"
      when TLV_META_TYPE_COMPLEX; "COMPLEX"
      else; 'unknown-meta-type'
      end
    stype = case type
      when PACKET_TYPE_REQUEST; "Request"
      when PACKET_TYPE_RESPONSE; "Response"
      when TLV_TYPE_REQUEST_ID; "REQUEST-ID"
      when TLV_TYPE_METHOD; "METHOD"
      when TLV_TYPE_RESULT; "RESULT"
      when TLV_TYPE_EXCEPTION; "EXCEPTION"
      when TLV_TYPE_STRING; "STRING"
      when TLV_TYPE_UINT; "UINT"
      when TLV_TYPE_BOOL; "BOOL"

      when TLV_TYPE_LENGTH; "LENGTH"
      when TLV_TYPE_DATA; "DATA"
      when TLV_TYPE_FLAGS; "FLAGS"

      when TLV_TYPE_CHANNEL_ID; "CHANNEL-ID"
      when TLV_TYPE_CHANNEL_TYPE; "CHANNEL-TYPE"
      when TLV_TYPE_CHANNEL_DATA; "CHANNEL-DATA"
      when TLV_TYPE_CHANNEL_DATA_GROUP; "CHANNEL-DATA-GROUP"
      when TLV_TYPE_CHANNEL_CLASS; "CHANNEL-CLASS"
      when TLV_TYPE_CHANNEL_PARENTID; "CHANNEL-PARENTID"

      when TLV_TYPE_SEEK_WHENCE; "SEEK-WHENCE"
      when TLV_TYPE_SEEK_OFFSET; "SEEK-OFFSET"
      when TLV_TYPE_SEEK_POS; "SEEK-POS"

      when TLV_TYPE_EXCEPTION_CODE; "EXCEPTION-CODE"
      when TLV_TYPE_EXCEPTION_STRING; "EXCEPTION-STRING"

      when TLV_TYPE_LIBRARY_PATH; "LIBRARY-PATH"
      when TLV_TYPE_TARGET_PATH; "TARGET-PATH"
      when TLV_TYPE_MIGRATE_PID; "MIGRATE-PID"
      when TLV_TYPE_MIGRATE_LEN; "MIGRATE-LEN"
      when TLV_TYPE_MIGRATE_PAYLOAD; "MIGRATE-PAYLOAD"
      when TLV_TYPE_MIGRATE_ARCH; "MIGRATE-ARCH"

      #when Extensions::Stdapi::TLV_TYPE_NETWORK_INTERFACE; 'network-interface'
      #when Extensions::Stdapi::TLV_TYPE_IP; 'ip-address'
      #when Extensions::Stdapi::TLV_TYPE_NETMASK; 'netmask'
      #when Extensions::Stdapi::TLV_TYPE_MAC_ADDRESS; 'mac-address'
      #when Extensions::Stdapi::TLV_TYPE_MAC_NAME; 'interface-name'
      #when Extensions::Stdapi::TLV_TYPE_IP6_SCOPE; 'address-scope'
      #when Extensions::Stdapi::TLV_TYPE_INTERFACE_MTU; 'interface-mtu'
      #when Extensions::Stdapi::TLV_TYPE_INTERFACE_FLAGS; 'interface-flags'
      #when Extensions::Stdapi::TLV_TYPE_INTERFACE_INDEX; 'interface-index'

      else; "unknown-#{type}"
      end
    val = value.inspect
    if val.length > 50
      val = val[0,50] + ' ..."'
    end
    group ||= (self.class.to_s =~ /Packet/)
    if group
      tlvs_inspect = "tlvs=[\n"
      @tlvs.each { |t|
        tlvs_inspect << "  #{t.inspect}\n"
      }
      tlvs_inspect << "]"
    else
      tlvs_inspect = "meta=#{meta.ljust 10} value=#{val}"
    end
    "#<#{self.class} type=#{stype.ljust 15} #{tlvs_inspect}>"
  end

  ##
  #
  # Conditionals
  #
  ##

  #
  # Checks to see if a TLVs meta type is equivalent to the meta type passed.
  #
  def meta_type?(meta)
    return (self.type & meta == meta)
  end

  #
  # Checks to see if the TLVs type is equivalent to the type passed.
  #
  def type?(type)
    return self.type == type
  end

  #
  # Checks to see if the TLVs value is equivalent to the value passed.
  #
  def value?(value)
    return self.value == value
  end

  ##
  #
  # Serializers
  #
  ##

  #
  # Converts the TLV to raw.
  #
  def to_r
    # Forcibly convert to ASCII-8BIT encoding
    raw = value.to_s.unpack("C*").pack("C*")

    if (self.type & TLV_META_TYPE_STRING == TLV_META_TYPE_STRING)
      raw += "\x00"
    elsif (self.type & TLV_META_TYPE_UINT == TLV_META_TYPE_UINT)
      raw = [value].pack("N")
    elsif (self.type & TLV_META_TYPE_QWORD == TLV_META_TYPE_QWORD)
      raw = [ self.htonq( value.to_i ) ].pack("Q")
    elsif (self.type & TLV_META_TYPE_BOOL == TLV_META_TYPE_BOOL)
      if (value == true)
        raw = [1].pack("c")
      else
        raw = [0].pack("c")
      end
    end

    # check if the tlv is to be compressed...
    if( @compress )
      raw_uncompressed = raw
      # compress the raw data
      raw_compressed = Rex::Text.zlib_deflate( raw_uncompressed )
      # check we have actually made the raw data smaller...
      # (small blobs often compress slightly larger then the origional)
      # if the compressed data is not smaller, we dont use the compressed data
      if( raw_compressed.length < raw_uncompressed.length )
        # if so, set the TLV's type to indicate compression is used
        self.type = self.type | TLV_META_TYPE_COMPRESSED
        # update the raw data with the uncompressed data length + compressed data
        # (we include the uncompressed data length as the C side will need to know this for decompression)
        raw = [ raw_uncompressed.length ].pack("N") + raw_compressed
      end
    end

    return [raw.length + 8, self.type].pack("NN") + raw
  end

  #
  # Translates the raw format of the TLV into a sanitize version.
  #
  def from_r(raw)
    self.value  = nil

    length, self.type = raw.unpack("NN");

    # check if the tlv value has been compressed...
    if( self.type & TLV_META_TYPE_COMPRESSED == TLV_META_TYPE_COMPRESSED )
      # set this TLV as using compression
      @compress = true
      # remove the TLV_META_TYPE_COMPRESSED flag from the tlv type to restore the
      # tlv type to its origional, allowing for transparent data compression.
      self.type = self.type ^ TLV_META_TYPE_COMPRESSED
      # decompress the compressed data (skipping the length and type DWORD's)
      raw_decompressed = Rex::Text.zlib_inflate( raw[8..length-1] )
      # update the length to reflect the decompressed data length (+8 for the length and type DWORD's)
      length = raw_decompressed.length + 8
      # update the raw buffer with the new length, decompressed data and updated type.
      raw = [length, self.type].pack("NN") + raw_decompressed
    end

    if (self.type & TLV_META_TYPE_STRING == TLV_META_TYPE_STRING)
      if (raw.length > 0)
        self.value = raw[8..length-2]
      else
        self.value = nil
      end
    elsif (self.type & TLV_META_TYPE_UINT == TLV_META_TYPE_UINT)
      self.value = raw.unpack("NNN")[2]
    elsif (self.type & TLV_META_TYPE_QWORD == TLV_META_TYPE_QWORD)
      self.value = raw.unpack("NNQ")[2]
      self.value = self.ntohq( self.value )
    elsif (self.type & TLV_META_TYPE_BOOL == TLV_META_TYPE_BOOL)
      self.value = raw.unpack("NNc")[2]

      if (self.value == 1)
        self.value = true
      else
        self.value = false
      end
    else
      self.value = raw[8..length-1]
    end

    return length;
  end

  protected

  def htonq( value )
    if( [1].pack( 's' ) == [1].pack( 'n' ) )
      return value
    end
    return [ value ].pack( 'Q' ).reverse.unpack( 'Q' ).first
  end

  def ntohq( value )
    return htonq( value )
  end

end

###
#
# Group TLVs contain zero or more TLVs
#
###
class GroupTlv < Tlv
  attr_accessor :tlvs

  ##
  #
  # Constructor
  #
  ##

  #
  # Initializes the group TLV container to the supplied type
  # and creates an empty TLV array.
  #
  def initialize(type)
    super(type)

    self.tlvs = [ ]
  end

  ##
  #
  # Group-based TLV accessors
  #
  ##

  #
  # Enumerates TLVs of the supplied type.
  #
  def each(type = TLV_TYPE_ANY, &block)
    get_tlvs(type).each(&block)
  end

  #
  # Synonym for each.
  #
  def each_tlv(type = TLV_TYPE_ANY, &block)
    each(type, &block)
  end

  #
  # Enumerates TLVs of a supplied type with indexes.
  #
  def each_with_index(type = TLV_TYPE_ANY, &block)
    get_tlvs(type).each_with_index(&block)
  end

  #
  # Synonym for each_with_index.
  #
  def each_tlv_with_index(type = TLV_TYPE_ANY, &block)
    each_with_index(type, block)
  end

  #
  # Returns an array of TLVs for the given type.
  #
  def get_tlvs(type)
    if (type == TLV_TYPE_ANY)
      return self.tlvs
    else
      type_tlvs = []

      self.tlvs.each() { |tlv|
        if (tlv.type?(type))
          type_tlvs << tlv
        end
      }

      return type_tlvs
    end
  end

  ##
  #
  # TLV management
  #
  ##

  #
  # Adds a TLV of a given type and value.
  #
  def add_tlv(type, value = nil, replace = false, compress=false)

    # If we should replace any TLVs with the same type...remove them first
    if (replace)
      each(type) { |tlv|
        if (tlv.type == type)
          self.tlvs.delete(tlv)
        end
      }
    end

    if (type & TLV_META_TYPE_GROUP == TLV_META_TYPE_GROUP)
      tlv = GroupTlv.new(type)
    else
      tlv = Tlv.new(type, value, compress)
    end

    self.tlvs << tlv

    return tlv
  end

  #
  # Adds zero or more TLVs to the packet.
  #
  def add_tlvs(tlvs)
    if (tlvs != nil)
      tlvs.each { |tlv|
        add_tlv(tlv['type'], tlv['value'])
      }
    end
  end

  #
  # Gets the first TLV of a given type.
  #
  def get_tlv(type, index = 0)
    type_tlvs = get_tlvs(type)

    if (type_tlvs.length > index)
      return type_tlvs[index]
    end

    return nil
  end

  #
  # Returns the value of a TLV if it exists, otherwise nil.
  #
  def get_tlv_value(type, index = 0)
    tlv = get_tlv(type, index)

    return (tlv != nil) ? tlv.value : nil
  end

  #
  # Returns an array of values for all tlvs of type type.
  #
  def get_tlv_values(type)
    get_tlvs(type).collect { |a| a.value }
  end

  #
  # Checks to see if the container has a TLV of a given type.
  #
  def has_tlv?(type)
    return get_tlv(type) != nil
  end

  #
  # Zeros out the array of TLVs.
  #
  def reset
    self.tlvs = []
  end

  ##
  #
  # Serializers
  #
  ##

  #
  # Converts all of the TLVs in the TLV array to raw and prefixes them
  # with a container TLV of this instance's TLV type.
  #
  def to_r
    raw = ''

    self.each() { |tlv|
      raw << tlv.to_r
    }

    return [raw.length + 8, self.type].pack("NN") + raw
  end

  #
  # Converts the TLV group container from raw to all of the individual
  # TLVs.
  #
  def from_r(raw)
    offset = 8

    # Reset the TLVs array
    self.tlvs = []
    self.type = raw.unpack("NN")[1]

    # Enumerate all of the TLVs
    while (offset < raw.length-1)

      tlv = nil

      # Get the length and type
      length, type = raw[offset..offset+8].unpack("NN")

      if (type & TLV_META_TYPE_GROUP == TLV_META_TYPE_GROUP)
        tlv = GroupTlv.new(type)
      else
        tlv = Tlv.new(type)
      end

      tlv.from_r(raw[offset..offset+length])

      # Insert it into the list of TLVs
      tlvs << tlv

      # Move up
      offset += length
    end
  end

end

###
#
# The logical meterpreter packet class
#
###
class Packet < GroupTlv
  attr_accessor :created_at

  ##
  #
  # Factory
  #
  ##

  #
  # Creates a request with the supplied method.
  #
  def Packet.create_request(method = nil)
    return Packet.new(PACKET_TYPE_REQUEST, method)
  end

  #
  # Creates a response to a request if one is provided.
  #
  def Packet.create_response(request = nil)
    response_type = PACKET_TYPE_RESPONSE
    method = nil

    if (request)
      if (request.type?(PACKET_TYPE_PLAIN_REQUEST))
        response_type = PACKET_TYPE_PLAIN_RESPONSE
      end

      method = request.method
    end

    return Packet.new(response_type, method)
  end

  ##
  #
  # Constructor
  #
  ##

  #
  # Initializes the packet to the supplied packet type and method,
  # if any.  If the packet is a request, a request identifier is
  # created.
  #
  def initialize(type = nil, method = nil)
    super(type)

    if (method)
      self.method = method
    end

    self.created_at = ::Time.now

    # If it's a request, generate a random request identifier
    if ((type == PACKET_TYPE_REQUEST) ||
        (type == PACKET_TYPE_PLAIN_REQUEST))
      rid = ''

      32.times { |val| rid << rand(10).to_s }

      add_tlv(TLV_TYPE_REQUEST_ID, rid)
    end
  end

  ##
  #
  # Conditionals
  #
  ##

  #
  # Checks to see if the packet is a response.
  #
  def response?
    return ((self.type == PACKET_TYPE_RESPONSE) ||
            (self.type == PACKET_TYPE_PLAIN_RESPONSE))
  end

  ##
  #
  # Accessors
  #
  ##

  #
  # Checks to see if the packet's method is equal to the supplied method.
  #
  def method?(method)
    return (get_tlv_value(TLV_TYPE_METHOD) == method)
  end

  #
  # Sets the packet's method TLV to the method supplied.
  #
  def method=(method)
    add_tlv(TLV_TYPE_METHOD, method, true)
  end

  #
  # Returns the value of the packet's method TLV.
  #
  def method
    return get_tlv_value(TLV_TYPE_METHOD)
  end

  #
  # Checks to see if the packet's result value is equal to the supplied
  # result.
  #
  def result?(result)
    return (get_tlv_value(TLV_TYPE_RESULT) == result)
  end

  #
  # Sets the packet's result TLV.
  #
  def result=(result)
    add_tlv(TLV_TYPE_RESULT, result, true)
  end

  #
  # Gets the value of the packet's result TLV.
  #
  def result
    return get_tlv_value(TLV_TYPE_RESULT)
  end

  #
  # Gets the value of the packet's request identifier TLV.
  #
  def rid
    return get_tlv_value(TLV_TYPE_REQUEST_ID)
  end
end


end; end; end