Module: Pwnlib::Shellcraft::Registers

Included in:
Generators::Helper::Runner
Defined in:
lib/pwnlib/shellcraft/registers.rb

Overview

Define register names and methods for shellcode generators.

Defined Under Namespace

Classes: Register

Constant Summary collapse

X86_BASEREGS = 
%w(ax cx dx bx sp bp si di ip).freeze
I386 = 
(X86_BASEREGS.map { |r| "e#{r}" } +
X86_BASEREGS +
%w(eflags cs ss ds es fs gs)).freeze
AMD64 = 
(X86_BASEREGS.map { |r| "r#{r}" } +
(8..15).map { |r| "r#{r}" } +
(8..15).map { |r| "r#{r}d" } +
I386).freeze
X86_ORDERED =

x86 registers in decreasing size

([
  %w(rax eax ax al),
  %w(rbx ebx bx bl),
  %w(rcx ecx cx cl),
  %w(rdx edx dx dl),
  %w(rdi edi di),
  %w(rsi esi si),
  %w(rbp ebp bp),
  %w(rsp esp sp)
] + (8..15).map { |r| ['', 'd', 'w', 'b'].map { |t| "r#{r}#{t}" } }).freeze
INTEL = 
(X86_ORDERED.each_with_object({}) do |row, obj|
  row.each_with_index do |reg, i|
    obj[reg] = Register.new(reg, 64 >> i)
  end
end).freeze

Class Method Summary collapse

Class Method Details

.bits_required(value) ⇒ Object 



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# File 'lib/pwnlib/shellcraft/registers.rb', line 135

def bits_required(value)
  bits = 0
  value = value.abs
  while value.positive?
    bits += 8
    value >>= 8
  end
  bits
end

.get_register(name) ⇒ Register?

Get a Register object by name.

Examples:

Registers.get_register('eax')
#=> Register(eax)
Registers.get_register(:ebx)
#=> Register(ebx)
Registers.get_register('xdd')
#=> nil

Parameters:

  • name (String, Symbol, Register) —

    The name of register. If name is already a Register object, name itself will be returned.

Returns:

  • (Register?) —

    Get the register with name name.



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# File 'lib/pwnlib/shellcraft/registers.rb', line 124

def get_register(name)
  return name if name.instance_of?(Register)
  return INTEL[name.to_s] if name.instance_of?(String) || name.instance_of?(Symbol)

  nil
end

.register?(obj) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pwnlib/shellcraft/registers.rb', line 131

def register?(obj)
  !get_register(obj).nil?
end

.registers ⇒ Object 



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# File 'lib/pwnlib/shellcraft/registers.rb', line 95

def registers
  {
    [32, 'i386', 'linux'] => ::Pwnlib::Shellcraft::Registers::I386,
    [64, 'amd64', 'linux'] => ::Pwnlib::Shellcraft::Registers::AMD64
  }[[context.bits, context.arch, context.os]]
end