class X86Translator(Translator):
"""x86 to IR Translator."""
def __init__(self, architecture_mode):
super(X86Translator, self).__init__()
# Set *Architecture Mode*. The translation of each instruction
# into the REIL language is based on this.
self._arch_mode = architecture_mode
# An instance of *ArchitectureInformation*.
self._arch_info = X86ArchitectureInformation(architecture_mode)
# An instance of a *VariableNamer*. This is used so all the
# temporary REIL registers are unique.
self._ir_name_generator = VariableNamer("t", separator="")
self._builder = ReilBuilder()
self._flags = {
"af": ReilRegisterOperand("af", 1),
"cf": ReilRegisterOperand("cf", 1),
"df": ReilRegisterOperand("df", 1),
"of": ReilRegisterOperand("of", 1),
"pf": ReilRegisterOperand("pf", 1),
"sf": ReilRegisterOperand("sf", 1),
"zf": ReilRegisterOperand("zf", 1),
}
if self._arch_mode == ARCH_X86_MODE_32:
self._sp = ReilRegisterOperand("esp", 32)
self._bp = ReilRegisterOperand("ebp", 32)
self._ip = ReilRegisterOperand("eip", 32)
self._ws = ReilImmediateOperand(4, 32) # word size
elif self._arch_mode == ARCH_X86_MODE_64:
self._sp = ReilRegisterOperand("rsp", 64)
self._bp = ReilRegisterOperand("rbp", 64)
self._ip = ReilRegisterOperand("rip", 64)
self._ws = ReilImmediateOperand(8, 64) # word size
def translate(self, instruction):
"""Return IR representation of an instruction.
"""
try:
trans_instrs = self.__translate(instruction)
except NotImplementedError:
unkn_instr = self._builder.gen_unkn()
unkn_instr.address = instruction.address << 8 | (0x0 & 0xff)
trans_instrs = [unkn_instr]
self.__log_not_supported_instruction(instruction)
except:
self.__log_translation_exception(instruction)
raise
return trans_instrs
def reset(self):
"""Restart IR register name generator.
"""
self._ir_name_generator.reset()
def __translate(self, instruction):
"""Translate a x86 instruction into REIL language.
:param instruction: a x86 instruction
:type instruction: X86Instruction
"""
# Retrieve translation function.
mnemonic = instruction.mnemonic
# Check whether it refers to the strings instruction or the sse instruction.
if instruction.mnemonic in ["movsd"]:
if instruction.bytes[0] not in ["\xa4", "\xa5"]:
mnemonic += "_sse"
# Translate instruction.
if mnemonic in translators.dispatcher:
tb = X86TranslationBuilder(self._ir_name_generator,
self._arch_mode)
translators.dispatcher[mnemonic](self, tb, instruction)
else:
raise NotImplementedError("Instruction Not Implemented")
return tb.instanciate(instruction.address)
def __log_not_supported_instruction(self, instruction):
bytes_str = " ".join("%02x" % ord(b) for b in instruction.bytes)
logger.info("Instruction not supported: %s (%s [%s])",
instruction.mnemonic, instruction, bytes_str)
def __log_translation_exception(self, instruction):
bytes_str = " ".join("%02x" % ord(b) for b in instruction.bytes)
logger.error("Failed to translate x86 to REIL: %s (%s)",
instruction,
bytes_str,
exc_info=True)
# Flag translation.
# ======================================================================== #
def _update_af(self, tb, oprnd0, oprnd1, result):
assert oprnd0.size == oprnd1.size
tmp0 = tb.temporal(8)
tmp1 = tb.temporal(8)
tmp2 = tb.temporal(8)
tmp3 = tb.temporal(8)
tmp4 = tb.temporal(8)
tmp5 = tb.temporal(8)
tmp6 = tb.temporal(8)
imm4 = tb.immediate(4, 8)
immn4 = tb.immediate(-4, 8)
af = self._flags["af"]
# Extract lower byte.
tb.add(self._builder.gen_str(oprnd0, tmp0))
tb.add(self._builder.gen_str(oprnd1, tmp1))
# Zero-extend lower 4 bits.
tb.add(self._builder.gen_bsh(tmp0, imm4, tmp2))
tb.add(self._builder.gen_bsh(tmp2, immn4, tmp4))
tb.add(self._builder.gen_bsh(tmp1, imm4, tmp3))
tb.add(self._builder.gen_bsh(tmp3, immn4, tmp5))
# Add up.
tb.add(self._builder.gen_add(tmp4, tmp5, tmp6))
# Move bit 4 to AF flag.
tb.add(self._builder.gen_bsh(tmp6, immn4, af))
def _update_af_sub(self, tb, oprnd0, oprnd1, result):
assert oprnd0.size == oprnd1.size
tmp0 = tb.temporal(8)
tmp1 = tb.temporal(8)
tmp2 = tb.temporal(8)
tmp3 = tb.temporal(8)
tmp4 = tb.temporal(8)
tmp5 = tb.temporal(8)
tmp6 = tb.temporal(8)
imm4 = tb.immediate(4, 8)
immn4 = tb.immediate(-4, 8)
af = self._flags["af"]
# Extract lower byte.
tb.add(self._builder.gen_str(oprnd0, tmp0))
tb.add(self._builder.gen_str(oprnd1, tmp1))
# Zero-extend lower 4 bits.
tb.add(self._builder.gen_bsh(tmp0, imm4, tmp2))
tb.add(self._builder.gen_bsh(tmp2, immn4, tmp4))
tb.add(self._builder.gen_bsh(tmp1, imm4, tmp3))
tb.add(self._builder.gen_bsh(tmp3, immn4, tmp5))
# Subtract
tb.add(self._builder.gen_sub(tmp4, tmp5, tmp6))
# Move bit 4 to AF flag.
tb.add(self._builder.gen_bsh(tmp6, immn4, af))
def _update_pf(self, tb, oprnd0, oprnd1, result):
tmp0 = tb.temporal(result.size)
tmp1 = tb.temporal(result.size)
tmp2 = tb.temporal(result.size)
tmp3 = tb.temporal(result.size)
tmp4 = tb.temporal(result.size)
tmp5 = tb.temporal(result.size)
imm1 = tb.immediate(1, result.size)
immn1 = tb.immediate(-1, result.size)
immn2 = tb.immediate(-2, result.size)
immn4 = tb.immediate(-4, result.size)
pf = self._flags["pf"]
# tmp1 = result ^ (result >> 4)
tb.add(self._builder.gen_bsh(result, immn4, tmp0))
tb.add(self._builder.gen_xor(result, tmp0, tmp1))
# tmp3 = tmp1 ^ (tmp1 >> 2)
tb.add(self._builder.gen_bsh(tmp1, immn2, tmp2))
tb.add(self._builder.gen_xor(tmp2, tmp1, tmp3))
# tmp5 = tmp3 ^ (tmp3 >> 1)
tb.add(self._builder.gen_bsh(tmp3, immn1, tmp4))
tb.add(self._builder.gen_xor(tmp4, tmp3, tmp5))
# Invert and save result.
tb.add(self._builder.gen_xor(tmp5, imm1, pf))
def _update_sf(self, tb, oprnd0, oprnd1, result):
# Create temporal variables.
tmp0 = tb.temporal(result.size)
mask0 = tb.immediate(2**(oprnd0.size - 1), result.size)
shift0 = tb.immediate(-(oprnd0.size - 1), result.size)
sf = self._flags["sf"]
tb.add(self._builder.gen_and(result, mask0, tmp0)) # filter sign bit
tb.add(self._builder.gen_bsh(tmp0, shift0, sf)) # extract sign bit
def _update_of(self, tb, oprnd0, oprnd1, result):
assert oprnd0.size == oprnd1.size
of = self._flags["of"]
imm0 = tb.immediate(1, 1)
tmp0 = tb.temporal(1)
tmp1 = tb.temporal(1)
tmp2 = tb.temporal(1)
tmp3 = tb.temporal(1)
# Extract sign bit.
oprnd0_sign = self._extract_sign_bit(tb, oprnd0)
oprnd1_sign = self._extract_sign_bit(tb, oprnd1)
result_sign = self._extract_bit(tb, result, oprnd0.size - 1)
# Compute OF.
tb.add(
self._builder.gen_xor(oprnd0_sign, oprnd1_sign,
tmp0)) # (sign bit oprnd0 ^ sign bit oprnd1)
tb.add(self._builder.gen_xor(
tmp0, imm0, tmp1)) # (sign bit oprnd0 ^ sign bit oprnd1 ^ 1)
tb.add(
self._builder.gen_xor(oprnd0_sign, result_sign,
tmp2)) # (sign bit oprnd0 ^ sign bit result)
tb.add(
self._builder.gen_and(tmp1, tmp2, tmp3)
) # (sign bit oprnd0 ^ sign bit oprnd1 ^ 1) & (sign bit oprnd0 ^ sign bit result)
# Save result.
tb.add(self._builder.gen_str(tmp3, of))
def _update_of_sub(self, tb, oprnd0, oprnd1, result):
assert oprnd0.size == oprnd1.size
of = self._flags["of"]
imm0 = tb.immediate(1, 1)
tmp0 = tb.temporal(1)
tmp1 = tb.temporal(1)
tmp2 = tb.temporal(1)
tmp3 = tb.temporal(1)
oprnd1_sign = tb.temporal(1)
# Extract sign bit.
oprnd0_sign = self._extract_sign_bit(tb, oprnd0)
oprnd1_sign_tmp = self._extract_sign_bit(tb, oprnd1)
result_sign = self._extract_bit(tb, result, oprnd0.size - 1)
# Invert sign bit of oprnd2.
tb.add(self._builder.gen_xor(oprnd1_sign_tmp, imm0, oprnd1_sign))
# Compute OF.
tb.add(
self._builder.gen_xor(oprnd0_sign, oprnd1_sign,
tmp0)) # (sign bit oprnd0 ^ sign bit oprnd1)
tb.add(self._builder.gen_xor(
tmp0, imm0, tmp1)) # (sign bit oprnd0 ^ sign bit oprnd1 ^ 1)
tb.add(
self._builder.gen_xor(oprnd0_sign, result_sign,
tmp2)) # (sign bit oprnd0 ^ sign bit result)
tb.add(
self._builder.gen_and(tmp1, tmp2, tmp3)
) # (sign bit oprnd0 ^ sign bit oprnd1 ^ 1) & (sign bit oprnd0 ^ sign bit result)
# Save result.
tb.add(self._builder.gen_str(tmp3, of))
def _update_cf(self, tb, oprnd0, oprnd1, result):
cf = self._flags["cf"]
imm0 = tb.immediate(2**oprnd0.size, result.size)
imm1 = tb.immediate(-oprnd0.size, result.size)
tmp0 = tb.temporal(result.size)
tb.add(self._builder.gen_and(result, imm0, tmp0)) # filter carry bit
tb.add(self._builder.gen_bsh(tmp0, imm1, cf))
def _update_zf(self, tb, oprnd0, oprnd1, result):
zf = self._flags["zf"]
imm0 = tb.immediate((2**oprnd0.size) - 1, result.size)
tmp0 = tb.temporal(oprnd0.size)
tb.add(self._builder.gen_and(result, imm0,
tmp0)) # filter low part of result
tb.add(self._builder.gen_bisz(tmp0, zf))
def _undefine_flag(self, tb, flag):
# NOTE: In every test I've made, each time a flag is leave
# undefined it is always set to 0.
imm = tb.immediate(0, flag.size)
tb.add(self._builder.gen_str(imm, flag))
def _clear_flag(self, tb, flag):
imm = tb.immediate(0, flag.size)
tb.add(self._builder.gen_str(imm, flag))
def _set_flag(self, tb, flag):
imm = tb.immediate(1, flag.size)
tb.add(self._builder.gen_str(imm, flag))
# Helpers.
# ======================================================================== #
def _evaluate_a(self, tb):
# above (CF=0 and ZF=0).
return tb._and_regs(tb._negate_reg(self._flags["cf"]),
tb._negate_reg(self._flags["zf"]))
def _evaluate_ae(self, tb):
# above or equal (CF=0)
return tb._negate_reg(self._flags["cf"])
def _evaluate_b(self, tb):
# below (CF=1)
return self._flags["cf"]
def _evaluate_be(self, tb):
# below or equal (CF=1 or ZF=1)
return tb._or_regs(self._flags["cf"], self._flags["zf"])
def _evaluate_c(self, tb):
# carry (CF=1)
return self._flags["cf"]
def _evaluate_e(self, tb):
# equal (ZF=1)
return self._flags["zf"]
def _evaluate_g(self, tb):
# greater (ZF=0 and SF=OF)
return tb._and_regs(
tb._negate_reg(self._flags["zf"]),
tb._equal_regs(self._flags["sf"], self._flags["of"]))
def _evaluate_ge(self, tb):
# greater or equal (SF=OF)
return tb._equal_regs(self._flags["sf"], self._flags["of"])
def _evaluate_l(self, tb):
# less (SF != OF)
return tb._unequal_regs(self._flags["sf"], self._flags["of"])
def _evaluate_le(self, tb):
# less or equal (ZF=1 or SF != OF)
return tb._or_regs(
self._flags["zf"],
tb._unequal_regs(self._flags["sf"], self._flags["of"]))
def _evaluate_na(self, tb):
# not above (CF=1 or ZF=1).
return tb._or_regs(self._flags["cf"], self._flags["zf"])
def _evaluate_nae(self, tb):
# not above or equal (CF=1)
return self._flags["cf"]
def _evaluate_nb(self, tb):
# not below (CF=0)
return tb._negate_reg(self._flags["cf"])
def _evaluate_nbe(self, tb):
# not below or equal (CF=0 and ZF=0)
return tb._and_regs(tb._negate_reg(self._flags["cf"]),
tb._negate_reg(self._flags["zf"]))
def _evaluate_nc(self, tb):
# not carry (CF=0)
return tb._negate_reg(self._flags["cf"])
def _evaluate_ne(self, tb):
# not equal (ZF=0)
return tb._negate_reg(self._flags["zf"])
def _evaluate_ng(self, tb):
# not greater (ZF=1 or SF != OF)
return tb._or_regs(
self._flags["zf"],
tb._unequal_regs(self._flags["sf"], self._flags["of"]))
def _evaluate_nge(self, tb):
# not greater or equal (SF != OF)
return tb._unequal_regs(self._flags["sf"], self._flags["of"])
def _evaluate_nl(self, tb):
# not less (SF=OF)
return tb._equal_regs(self._flags["sf"], self._flags["of"])
def _evaluate_nle(self, tb):
# not less or equal (ZF=0 and SF=OF)
return tb._and_regs(
tb._negate_reg(self._flags["zf"]),
tb._equal_regs(self._flags["sf"], self._flags["of"]))
def _evaluate_no(self, tb):
# not overflow (OF=0)
return tb._negate_reg(self._flags["of"])
def _evaluate_np(self, tb):
# not parity (PF=0)
return tb._negate_reg(self._flags["pf"])
def _evaluate_ns(self, tb):
# not sign (SF=0)
return tb._negate_reg(self._flags["sf"])
def _evaluate_nz(self, tb):
# not zero (ZF=0)
return tb._negate_reg(self._flags["zf"])
def _evaluate_o(self, tb):
# overflow (OF=1)
return self._flags["of"]
def _evaluate_p(self, tb):
# parity (PF=1)
return self._flags["pf"]
def _evaluate_pe(self, tb):
# parity even (PF=1)
return self._flags["pf"]
def _evaluate_po(self, tb):
# parity odd (PF=0)
return tb._negate_reg(self._flags["pf"])
def _evaluate_s(self, tb):
# sign (SF=1)
return self._flags["sf"]
def _evaluate_z(self, tb):
# zero (ZF=1)
return self._flags["zf"]
# Helpers.
# ======================================================================== #
def _extract_bit(self, tb, reg, bit):
assert (0 <= bit < reg.size)
tmp = tb.temporal(reg.size)
ret = tb.temporal(1)
tb.add(self._builder.gen_bsh(reg, tb.immediate(-bit, reg.size),
tmp)) # shift to LSB
tb.add(self._builder.gen_and(tmp, tb.immediate(1, reg.size),
ret)) # filter LSB
return ret
def _extract_msb(self, tb, reg):
return self._extract_bit(tb, reg, reg.size - 1)
def _extract_sign_bit(self, tb, reg):
return self._extract_msb(tb, reg)
class TranslationBuilder(object):
def __init__(self, ir_name_generator, architecture_information):
self._ir_name_generator = ir_name_generator
self._instructions = []
self._builder = ReilBuilder()
self._arch_info = architecture_information
def add(self, instr):
self._instructions.append(instr)
def temporal(self, size):
return ReilRegisterOperand(self._ir_name_generator.get_next(), size)
def immediate(self, value, size):
return ReilImmediateOperand(value, size)
def label(self, name):
return Label(name)
def instanciate(self, address):
# Set instructions address.
instrs = self._instructions
for instr in instrs:
instr.address = address << 8
instrs = self._resolve_loops(instrs)
return instrs
# Auxiliary functions
# ======================================================================== #
def _resolve_loops(self, instrs):
idx_by_labels = {}
# Collect labels.
# curr = 0
# for index, instr in enumerate(instrs):
# if isinstance(instr, Label):
# idx_by_labels[instr.name] = curr
#
# del instrs[index]
# else:
# curr += 1
# TODO: Hack to avoid deleting while iterating
instrs_no_labels = []
curr = 0
for i in instrs:
if isinstance(i, Label):
idx_by_labels[i.name] = curr
else:
instrs_no_labels.append(i)
curr += 1
instrs[:] = instrs_no_labels
# Resolve instruction addresses and JCC targets.
for index, instr in enumerate(instrs):
assert isinstance(instr, ReilInstruction)
instr.address |= index
if instr.mnemonic == ReilMnemonic.JCC:
target = instr.operands[2]
if isinstance(target, Label):
idx = idx_by_labels[target.name]
address = (instr.address & ~0xff) | idx
instr.operands[2] = ReilImmediateOperand(
address, self._arch_info.address_size + 8)
return instrs
def _all_ones_imm(self, reg):
return self.immediate((2**reg.size) - 1, reg.size)
def _negate_reg(self, reg):
neg = self.temporal(reg.size)
self.add(self._builder.gen_xor(reg, self._all_ones_imm(reg), neg))
return neg
def _and_regs(self, reg1, reg2):
ret = self.temporal(reg1.size)
self.add(self._builder.gen_and(reg1, reg2, ret))
return ret
def _or_regs(self, reg1, reg2):
ret = self.temporal(reg1.size)
self.add(self._builder.gen_or(reg1, reg2, ret))
return ret
def _xor_regs(self, reg1, reg2):
ret = self.temporal(reg1.size)
self.add(self._builder.gen_xor(reg1, reg2, ret))
return ret
def _equal_regs(self, reg1, reg2):
return self._negate_reg(self._xor_regs(reg1, reg2))
def _unequal_regs(self, reg1, reg2):
return self._xor_regs(reg1, reg2)
def _shift_reg(self, reg, sh):
ret = self.temporal(reg.size)
self.add(self._builder.gen_bsh(reg, sh, ret))
return ret
def _extract_bit(self, reg, bit):
assert (0 <= bit < reg.size)
tmp = self.temporal(reg.size)
ret = self.temporal(1)
self.add(
self._builder.gen_bsh(reg, self.immediate(-bit, reg.size),
tmp)) # shift to LSB
self.add(self._builder.gen_and(tmp, self.immediate(1, reg.size),
ret)) # filter LSB
return ret
# Same as before but the bit number is indicated by a register and it will be resolved at runtime
def _extract_bit_with_register(self, reg, bit):
# assert(bit >= 0 and bit < reg.size2) # It is assumed, it is not checked
tmp = self.temporal(reg.size)
neg_bit = self.temporal(reg.size)
ret = self.temporal(1)
self.add(
self._builder.gen_sub(
self.immediate(0, bit.size), bit,
neg_bit)) # as left bit is indicated by a negative number
self.add(self._builder.gen_bsh(reg, neg_bit, tmp)) # shift to LSB
self.add(self._builder.gen_and(tmp, self.immediate(1, reg.size),
ret)) # filter LSB
return ret
def _extract_msb(self, reg):
return self._extract_bit(reg, reg.size - 1)
def _extract_sign_bit(self, reg):
return self._extract_msb(reg)
def _greater_than_or_equal(self, reg1, reg2):
assert (reg1.size == reg2.size)
result = self.temporal(reg1.size * 2)
self.add(self._builder.gen_sub(reg1, reg2, result))
sign = self._extract_bit(result, reg1.size - 1)
overflow = self._overflow_from_sub(reg1, reg2, result)
return self._equal_regs(sign, overflow)
def _jump_to(self, target):
self.add(self._builder.gen_jcc(self.immediate(1, 1), target))
def _jump_if_zero(self, reg, label):
is_zero = self.temporal(1)
self.add(self._builder.gen_bisz(reg, is_zero))
self.add(self._builder.gen_jcc(is_zero, label))
def _add_to_reg(self, reg, value):
res = self.temporal(reg.size)
self.add(self._builder.gen_add(reg, value, res))
return res
def _sub_to_reg(self, reg, value):
res = self.temporal(reg.size)
self.add(self._builder.gen_sub(reg, value, res))
return res
def _overflow_from_sub(self, oprnd0, oprnd1, result):
op1_sign = self._extract_bit(oprnd0, oprnd0.size - 1)
op2_sign = self._extract_bit(oprnd1, oprnd0.size - 1)
res_sign = self._extract_bit(result, oprnd0.size - 1)
return self._and_regs(self._unequal_regs(op1_sign, op2_sign),
self._unequal_regs(op1_sign, res_sign))