metasploit-framework/lib/postgres/binary_reader.rb

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require 'postgres_msf'
require 'postgres/byteorder'
# Namespace for Metasploit branch.
module Msf
module Db
# This mixin solely depends on method read(n), which must be defined
# in the class/module where you mixin this module.
module BinaryReaderMixin
# == 8 bit
# no byteorder for 8 bit!
def read_word8
ru(1, 'C')
end
def read_int8
ru(1, 'c')
end
alias read_byte read_word8
# == 16 bit
# === Unsigned
def read_word16_native
ru(2, 'S')
end
def read_word16_little
ru(2, 'v')
end
def read_word16_big
ru(2, 'n')
end
# === Signed
def read_int16_native
ru(2, 's')
end
def read_int16_little
# swap bytes if native=big (but we want little)
ru_swap(2, 's', ByteOrder::Big)
end
def read_int16_big
# swap bytes if native=little (but we want big)
ru_swap(2, 's', ByteOrder::Little)
end
# == 32 bit
# === Unsigned
def read_word32_native
ru(4, 'L')
end
def read_word32_little
ru(4, 'V')
end
def read_word32_big
ru(4, 'N')
end
# === Signed
def read_int32_native
ru(4, 'l')
end
def read_int32_little
# swap bytes if native=big (but we want little)
ru_swap(4, 'l', ByteOrder::Big)
end
def read_int32_big
# swap bytes if native=little (but we want big)
ru_swap(4, 'l', ByteOrder::Little)
end
# == Aliases
alias read_uint8 read_word8
# add some short-cut functions
%w(word16 int16 word32 int32).each do |typ|
alias_method "read_#{typ}_network", "read_#{typ}_big"
end
{:word16 => :uint16, :word32 => :uint32}.each do |old, new|
['_native', '_little', '_big', '_network'].each do |bo|
alias_method "read_#{new}#{bo}", "read_#{old}#{bo}"
end
end
# read exactly n characters, otherwise raise an exception.
def readn(n)
str = read(n)
raise "couldn't read #{n} characters" if str.nil? or str.size != n
str
end
private
# shortcut method for readn+unpack
def ru(size, template)
readn(size).unpack(template).first
end
# same as method +ru+, but swap bytes if native byteorder == _byteorder_
def ru_swap(size, template, byteorder)
str = readn(size)
str.reverse! if ByteOrder.byteorder == byteorder
str.unpack(template).first
end
end
end
end