105 lines
3.7 KiB
Ruby
105 lines
3.7 KiB
Ruby
#!/usr/bin/ruby
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# shikata ga nai implementation using poly block generation
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require 'rex'
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require 'rex/poly'
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raw_length = 8
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raw_buf = "\xcc\xcc\xcc\xcc"
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raw_buf = "\xdd\xdd\xdd\xdd"
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def fpu_instructions
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fpus = []
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0xe8.upto(0xee) { |x| fpus << "\xd9" + x.chr }
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0xc0.upto(0xcf) { |x| fpus << "\xd9" + x.chr }
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0xc0.upto(0xdf) { |x| fpus << "\xda" + x.chr }
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0xc0.upto(0xdf) { |x| fpus << "\xdb" + x.chr }
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0xc0.upto(0xc7) { |x| fpus << "\xdd" + x.chr }
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fpus << "\xd9\xd0"
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fpus << "\xd9\xe1"
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fpus << "\xdb\xe1"
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fpus << "\xd9\xf6"
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fpus << "\xd9\xf7"
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fpus << "\xd9\xe5"
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fpus
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end
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# Declare logical registers
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count_reg = Rex::Poly::LogicalRegister::X86.new('count', 'ecx')
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addr_reg = Rex::Poly::LogicalRegister::X86.new('addr')
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key_reg = Rex::Poly::LogicalRegister::X86.new('key')
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# Declare individual blocks
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endb = Rex::Poly::SymbolicBlock::End.new
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fpu = Rex::Poly::LogicalBlock.new('fpu',
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*fpu_instructions)
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fnstenv = Rex::Poly::LogicalBlock.new('fnstenv',
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"\xd9\x74\x24\xf4")
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popeip = Rex::Poly::LogicalBlock.new('popeip',
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Proc.new { |b| (0x58 + b.regnum_of(addr_reg)).chr })
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clear_register = Rex::Poly::LogicalBlock.new('clear_register',
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"\x31\xc9",
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"\x29\xc9",
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"\x33\xc9",
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"\x2b\xc9")
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init_counter = Rex::Poly::LogicalBlock.new('init_counter')
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if (raw_length <= 255)
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init_counter.add_perm("\xb1" + [ raw_length ].pack('C'))
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else
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init_counter.add_perm("\x66\xb9" + [ raw_length ].pack('v'))
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end
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init_key = Rex::Poly::LogicalBlock.new('init_key',
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Proc.new { |b| (0xb8 + b.regnum_of(key_reg)).chr + 'XORK'})
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loop_block = Rex::Poly::LogicalBlock.new('loop_block')
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xor = Proc.new { |b| "\x31" + (0x40 + b.regnum_of(addr_reg) + (8 * b.regnum_of(key_reg))).chr }
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xor1 = Proc.new { |b| xor.call(b) + [ (b.offset_of(endb) - b.offset_of(fpu) - 4) ].pack('c') }
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xor2 = Proc.new { |b| xor.call(b) + [ (b.offset_of(endb) - b.offset_of(fpu) - 8) ].pack('c') }
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add = Proc.new { |b| "\x03" + (0x40 + b.regnum_of(addr_reg) + (8 * b.regnum_of(key_reg))).chr }
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add1 = Proc.new { |b| add.call(b) + [ (b.offset_of(endb) - b.offset_of(fpu) - 4) ].pack('c') }
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add2 = Proc.new { |b| add.call(b) + [ (b.offset_of(endb) - b.offset_of(fpu) - 8) ].pack('c') }
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sub4 = Proc.new { |b| "\x83" + (0xe8 + b.regnum_of(addr_reg)).chr + "\xfc" }
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add4 = Proc.new { |b| "\x83" + (0xc0 + b.regnum_of(addr_reg)).chr + "\x04" }
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#xor = Proc.new { |b| "\x31" + (0x40 + b.regnum_of(addr_reg) + (8 * b.regnum_of(key_reg))).chr }
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#xor1 = Proc.new { |b| xor.call(b) + (b.offset_of(endb) - b.offset_of(fpu) - 4).chr }
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#xor2 = Proc.new { |b| xor.call(b) + (b.offset_of(endb) - b.offset_of(fpu) - 8).chr }
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#add = Proc.new { |b| "\x03" + (0x40 + b.regnum_of(addr_reg) + (8 * b.regnum_of(key_reg))).chr }
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#add1 = Proc.new { |b| add.call(b) + (b.offset_of(endb) - b.offset_of(fpu) - 4).chr }
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#add2 = Proc.new { |b| add.call(b) + (b.offset_of(endb) - b.offset_of(fpu) - 8).chr }
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#sub4 = Proc.new { |b| "\x83" + (0xe8 + b.regnum_of(addr_reg)).chr + "\xfc" }
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#add4 = Proc.new { |b| "\x83" + (0xc0 + b.regnum_of(addr_reg)).chr + "\x04" }
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loop_block.add_perm(
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Proc.new { |b| xor1.call(b) + add1.call(b) + sub4.call(b) },
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Proc.new { |b| xor1.call(b) + sub4.call(b) + add2.call(b) },
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Proc.new { |b| sub4.call(b) + xor2.call(b) + add2.call(b) },
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Proc.new { |b| xor1.call(b) + add1.call(b) + add4.call(b) },
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Proc.new { |b| xor1.call(b) + add4.call(b) + add2.call(b) },
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Proc.new { |b| add4.call(b) + xor2.call(b) + add2.call(b) })
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loop_inst = Rex::Poly::LogicalBlock.new('loop_inst',
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"\xe2\xf5")
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# Define block dependencies
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fnstenv.depends_on(fpu)
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popeip.depends_on(fnstenv)
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init_counter.depends_on(clear_register)
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loop_block.depends_on(popeip, init_counter, init_key)
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loop_inst.depends_on(loop_block)
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# Generate a permutation
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puts loop_inst.generate([
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Rex::Arch::X86::ESP,
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Rex::Arch::X86::ECX ])
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