928 lines
30 KiB
Python
928 lines
30 KiB
Python
import pefile # type: ignore
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import struct
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import sys
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from iced_x86 import Decoder, Instruction, Formatter, FormatterSyntax, FormatMnemonicOptions
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from typing import Any, List, Dict, Optional
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class Memory:
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def __init__(self) -> None:
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self.values: Dict[int, int] = {}
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self.defaults: Dict[int, bytes] = {}
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def init(self, min_offset: int, max_offset: int) -> None:
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for i in range(min_offset + 1, max_offset + 1):
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self.store(i, self.load(i, 1))
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def store(self, offset: int, data: bytes) -> None:
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for i, b in enumerate(data):
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self.values[i + offset] = b
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def load(self, offset: int, length: int) -> bytes:
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data: List[int] = []
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for i in range(offset, offset + length):
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if i in self.values:
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# Return modified value.
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data.append(self.values[i])
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else:
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# Attempt to return the default.
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for virtual_start in self.defaults:
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if i >= virtual_start and i < (virtual_start + len(self.defaults[virtual_start])):
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data.append(self.defaults[virtual_start][i - virtual_start])
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break
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else:
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# Nothing here, return initialized RAM.
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data.append(0)
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return bytes(data)
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class Registers:
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def __init__(self, stack: int) -> None:
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self.rax = 0
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self.rbx = 0
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self.rcx = 0
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self.rdx = 0
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self.rsi = 0
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self.rdi = 0
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self.rbp = 0
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self.rsp = stack
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self.zf = False
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self.sf = False
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class JumpException(Exception):
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def __init__(self, address: int, message: str) -> None:
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super().__init__(message)
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self.address = address
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class RetException(Exception):
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pass
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class PEFile:
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def __init__(self, data: bytes) -> None:
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self.data = data
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self.__pe = pefile.PE(data=data, fast_load=True)
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self.__adhoc_mapping: Dict[int, int] = {}
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def virtual_to_physical(self, offset: int) -> int:
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for section in self.__pe.sections:
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start = section.VirtualAddress + self.__pe.OPTIONAL_HEADER.ImageBase
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end = start + section.SizeOfRawData
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if offset >= start and offset < end:
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return (offset - start) + section.PointerToRawData
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for virtual, physical in self.__adhoc_mapping.items():
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if offset == virtual:
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return physical
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raise Exception(f"Couldn't find physical offset for virtual offset 0x{offset:08x}")
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def physical_to_virtual(self, offset: int) -> int:
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for section in self.__pe.sections:
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start = section.PointerToRawData
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end = start + section.SizeOfRawData
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if offset >= start and offset < end:
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return (offset - start) + section.VirtualAddress + self.__pe.OPTIONAL_HEADER.ImageBase
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for virtual, physical in self.__adhoc_mapping.items():
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if offset == physical:
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return virtual
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raise Exception(f"Couldn't find virtual offset for physical offset 0x{offset:08x}")
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def is_virtual(self, offset: int) -> bool:
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return offset >= self.__pe.OPTIONAL_HEADER.ImageBase
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def is_64bit(self) -> bool:
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return hex(self.__pe.FILE_HEADER.Machine) == '0x8664'
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def emulate_code(self, start: int, end: int, verbose: bool = False) -> None:
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if self.is_virtual(start):
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# Assume this is virtual
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start = self.virtual_to_physical(start)
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if self.is_virtual(end):
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# Assume this is virtual
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end = self.virtual_to_physical(end)
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registers = Registers(0xFFFFFFFFFFFFFFFF if self.is_64bit() else 0xFFFFFFFF)
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memory = self.__to_memory()
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decoder = Decoder(64 if self.is_64bit() else 32, self.data[start:end], ip=self.physical_to_virtual(start))
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self.__emulate_chunk(registers, memory, [i for i in decoder], verbose)
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# Replace memory that we care about.
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self.__update(memory)
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def emulate_function(self, start: int, verbose: bool = False) -> None:
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if self.is_virtual(start):
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# Assume this is virtual
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start = self.virtual_to_physical(start)
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registers = Registers(0xFFFFFFFFFFFFFFFF if self.is_64bit() else 0xFFFFFFFF)
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memory = self.__to_memory()
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# Need to fetch one at a time, emulating until we get a ret.
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loc = start
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end = len(self.data)
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while True:
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decoder = Decoder(64 if self.is_64bit() else 32, self.data[loc:end], ip=self.physical_to_virtual(loc))
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chunk = [decoder.decode()]
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try:
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# First attempt to just run the instruction as normal.
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self.__emulate_chunk(registers, memory, chunk, verbose)
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loc = self.virtual_to_physical(chunk[0].next_ip)
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except JumpException as jmp:
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# We need to jump elsewhere.
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loc = self.virtual_to_physical(jmp.address)
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except RetException:
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# We're done!
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break
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# Replace memory that we care about.
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self.__update(memory)
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def __to_memory(self) -> Memory:
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memory = Memory()
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for section in self.__pe.sections:
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virtual = section.VirtualAddress + self.__pe.OPTIONAL_HEADER.ImageBase
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length = section.SizeOfRawData
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physical = self.virtual_to_physical(virtual)
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memory.defaults[virtual] = self.data[physical:(physical + length)]
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for virtual, physical in self.__adhoc_mapping.items():
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memory.values[virtual] = self.data[physical]
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return memory
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def __update(self, memory: Memory) -> None:
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newdata = [x for x in self.data]
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for virtual in sorted(memory.values):
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try:
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physical = self.virtual_to_physical(virtual)
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newdata[physical] = memory.values[virtual]
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except Exception:
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# This is outside of the data we are tracking. Its really not ideal
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# that we are just shoving this at the end of the data, but it should
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# work for what we care about.
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physical = len(newdata)
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self.__adhoc_mapping[virtual] = physical
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newdata.append(memory.values[virtual])
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self.data = bytes(newdata)
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self.__pe = pefile.PE(data=self.data, fast_load=True)
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def __emulate_chunk(self, registers: Registers, memory: Memory, chunk: List[Instruction], verbose: bool) -> None:
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if verbose:
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def vprint(*args: Any, **kwargs: Any) -> None:
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print(*args, **kwargs, file=sys.stderr)
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else:
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def vprint(*args: Any, **kwargs: Any) -> None:
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pass
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# Stuck here so that jump can bind to it.
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loc: int = 0
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def jump(destination: int) -> None:
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nonlocal loc
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for i in range(len(chunk)):
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if chunk[i].ip == destination:
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# Jump to this instruction.
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loc = i
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break
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else:
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if destination == chunk[-1].next_ip:
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# Jump to the end, we're done.
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loc = len(chunk)
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else:
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raise JumpException(destination, f"Jumping to {hex(destination)} which is outside of our evaluation range!")
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formatter = Formatter(FormatterSyntax.NASM) # type: ignore
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while loc < len(chunk):
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inst = chunk[loc]
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loc = loc + 1
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mnemonic = formatter.format_mnemonic(inst, FormatMnemonicOptions.NO_PREFIXES) # type: ignore
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if mnemonic == "mov":
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dest = formatter.format_operand(inst, 0)
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src = formatter.format_operand(inst, 1)
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vprint(f"mov {dest}, {src}")
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size = get_size(src) or get_size(dest)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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result = fetch(registers, memory, size, src)
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assign(registers, memory, size, dest, result)
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elif mnemonic == "movzx":
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dest = formatter.format_operand(inst, 0)
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src = formatter.format_operand(inst, 1)
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vprint(f"movzx {dest}, {src}")
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srcsize = get_size(src)
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dstsize = get_size(dest)
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if srcsize is None or dstsize is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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result = fetch(registers, memory, srcsize, src)
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assign(registers, memory, dstsize, dest, result)
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elif mnemonic == "add":
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dest = formatter.format_operand(inst, 0)
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amt = formatter.format_operand(inst, 1)
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vprint(f"add {dest}, {amt}")
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size = get_size(amt) or get_size(dest)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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# Special case for adjusting ESP, to make sure our memory contains zeros for reading
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# out the stack later.
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if dest == "esp":
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before = fetch(registers, memory, size, dest)
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after = before + fetch(registers, memory, size, amt)
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memory.init(min(before, after), max(before, after))
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assign(registers, memory, size, dest, after)
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else:
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result = fetch(registers, memory, size, dest) + fetch(registers, memory, size, amt)
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assign(registers, memory, size, dest, result)
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elif mnemonic == "sub":
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dest = formatter.format_operand(inst, 0)
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amt = formatter.format_operand(inst, 1)
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vprint(f"sub {dest}, {amt}")
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size = get_size(amt) or get_size(dest)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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# Special case for adjusting ESP, to make sure our memory contains zeros for reading
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# out the stack later.
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if dest == "esp":
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before = fetch(registers, memory, size, dest)
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after = before - fetch(registers, memory, size, amt)
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memory.init(min(before, after), max(before, after))
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assign(registers, memory, size, dest, after)
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else:
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result = fetch(registers, memory, size, dest) - fetch(registers, memory, size, amt)
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assign(registers, memory, size, dest, result)
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elif mnemonic == "imul":
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dest = formatter.format_operand(inst, 0)
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mult = formatter.format_operand(inst, 1)
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try:
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const = formatter.format_operand(inst, 2)
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vprint(f"imul {dest}, {mult}, {const}")
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except Exception:
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const = None
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vprint(f"imul {dest}, {mult}")
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size = get_size(mult) or get_size(dest) or (get_size(const) if const is not None else None)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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if const is None:
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result = fetch(registers, memory, size, dest) * fetch(registers, memory, size, mult)
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else:
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result = fetch(registers, memory, size, mult) * get_value(const)
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assign(registers, memory, size, dest, result)
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elif mnemonic == "push":
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src = formatter.format_operand(inst, 0)
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vprint(f"push {src}")
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size = get_size(src)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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result = fetch(registers, memory, size, src)
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registers.rsp -= size
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assign(registers, memory, size, "[rsp]" if self.is_64bit() else "[esp]", result)
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elif mnemonic == "pop":
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dest = formatter.format_operand(inst, 0)
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vprint(f"pop {dest}")
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size = get_size(src)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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result = fetch(registers, memory, size, "[rsp]" if self.is_64bit() else "[esp]")
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assign(registers, memory, size, dest, result)
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registers.rsp += size
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elif mnemonic == "test":
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op1 = formatter.format_operand(inst, 0)
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op2 = formatter.format_operand(inst, 1)
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vprint(f"test {op1}, {op2}")
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size = get_size(op1) or get_size(op2)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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result = fetch(registers, memory, size, op1) & fetch(registers, memory, size, op2)
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registers.zf = result == 0
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if size == 1:
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registers.sf = (result & 0x80) != 0
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if size == 2:
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registers.sf = (result & 0x8000) != 0
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if size == 4:
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registers.sf = (result & 0x80000000) != 0
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if size == 8:
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registers.sf = (result & 0x8000000000000000) != 0
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elif mnemonic == "jne":
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dest = formatter.format_operand(inst, 0)
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vprint(f"jnz {dest}")
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if not registers.zf:
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destination = get_value(dest)
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if destination is None:
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raise Exception(f"Jumping to unsupported destination {dest}")
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jump(destination)
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elif mnemonic == "je":
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dest = formatter.format_operand(inst, 0)
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vprint(f"jz {dest}")
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if registers.zf:
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destination = get_value(dest)
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if destination is None:
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raise Exception(f"Jumping to unsupported destination {dest}")
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jump(destination)
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elif mnemonic == "jns":
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dest = formatter.format_operand(inst, 0)
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vprint(f"jns {dest}")
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if not registers.sf:
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destination = get_value(dest)
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if destination is None:
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raise Exception(f"Jumping to unsupported destination {dest}")
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jump(destination)
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elif mnemonic == "js":
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dest = formatter.format_operand(inst, 0)
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vprint(f"js {dest}")
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if registers.sf:
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destination = get_value(dest)
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if destination is None:
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raise Exception(f"Jumping to unsupported destination {dest}")
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jump(destination)
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elif mnemonic == "jmp":
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dest = formatter.format_operand(inst, 0)
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vprint(f"jmp {dest}")
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destination = get_value(dest)
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if destination is None:
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raise Exception(f"Jumping to unsupported destination {dest}")
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jump(destination)
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elif mnemonic == "and":
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dest = formatter.format_operand(inst, 0)
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src = formatter.format_operand(inst, 1)
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vprint(f"and {dest}, {src}")
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size = get_size(src) or get_size(dest)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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result = fetch(registers, memory, size, dest) & fetch(registers, memory, size, src)
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assign(registers, memory, size, dest, result)
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elif mnemonic == "or":
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dest = formatter.format_operand(inst, 0)
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src = formatter.format_operand(inst, 1)
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vprint(f"or {dest}, {src}")
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size = get_size(src) or get_size(dest)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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result = fetch(registers, memory, size, dest) | fetch(registers, memory, size, src)
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assign(registers, memory, size, dest, result)
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elif mnemonic == "xor":
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dest = formatter.format_operand(inst, 0)
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src = formatter.format_operand(inst, 1)
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vprint(f"xor {dest}, {src}")
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size = get_size(src) or get_size(dest)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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result = fetch(registers, memory, size, dest) ^ fetch(registers, memory, size, src)
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assign(registers, memory, size, dest, result)
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elif mnemonic == "lea":
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dest = formatter.format_operand(inst, 0)
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src = formatter.format_operand(inst, 1)
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vprint(f"lea {dest}, {src}")
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size = get_size(src) or get_size(dest)
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if size is None:
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raise Exception(f"Could not determine size of {mnemonic} operation!")
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result = get_address(registers, src)
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if result is None:
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raise Exception(f"Could not compute effective address for {mnemonic} operation!")
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assign(registers, memory, size, dest, result)
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elif mnemonic == "ret":
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vprint("ret")
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raise RetException("Encountered {mnemonic} instruction but we aren't in function context!")
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else:
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raise Exception(f"Unsupported mnemonic {mnemonic}!")
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def sanitize(indirect: str) -> str:
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"""
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Given an indirect address or a value from iced-x86 as formatted by the
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operand formatter, sanitize it by getting rid of size specifiers.
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"""
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if indirect[:5] == "near ":
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indirect = indirect[5:]
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if indirect[:4] == "rel ":
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indirect = indirect[4:]
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if indirect[:6] == "short ":
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indirect = indirect[6:]
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if indirect[:5] == "byte ":
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indirect = indirect[5:]
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if indirect[:5] == "word ":
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indirect = indirect[5:]
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if indirect[:6] == "dword ":
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indirect = indirect[6:]
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if indirect[:6] == "qword ":
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indirect = indirect[6:]
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return indirect
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def get_address(registers: Registers, indirect: str) -> Optional[int]:
|
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"""
|
|
Given an indirect reference as formatted by the iced-x86 operand formatter,
|
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resolve it to an actual 32-bit address that we should load from or store to.
|
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This optionally supports indirect register address format so that we can
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conveniently specify fetches and stores from the stack. If the value we
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receive is not actually an indirect reference, return None.
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"""
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indirect = sanitize(indirect)
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|
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if indirect[0] == "[" and indirect[-1] == "]":
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indirect = sanitize(indirect[1:-1])
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adjust = 0
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if '+' in indirect:
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indirect, const = indirect.split('+', 1)
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indirect = sanitize(indirect)
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const = sanitize(const)
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|
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if const[-1] == 'h':
|
|
adjust = int(const[:-1], 16)
|
|
else:
|
|
adjust = int(const, 10)
|
|
elif '-' in indirect:
|
|
indirect, const = indirect.split('-', 1)
|
|
indirect = sanitize(indirect)
|
|
const = sanitize(const)
|
|
|
|
if const[-1] == 'h':
|
|
adjust = -int(const[:-1], 16)
|
|
else:
|
|
adjust = -int(const, 10)
|
|
|
|
if indirect[-1] == 'h':
|
|
return int(indirect[:-1], 16) + adjust
|
|
|
|
# Register-based indirect modes.
|
|
if indirect == "rsp":
|
|
return registers.rsp + adjust
|
|
if indirect == "esp":
|
|
return (registers.rsp & 0xFFFFFFFF) + adjust
|
|
if indirect == "sp":
|
|
return (registers.rsp & 0xFFFF) + adjust
|
|
if indirect == "spl":
|
|
return (registers.rsp & 0xFF) + adjust
|
|
if indirect == "rbp":
|
|
return registers.rbp + adjust
|
|
if indirect == "ebp":
|
|
return (registers.rbp & 0xFFFFFFFF) + adjust
|
|
if indirect == "bp":
|
|
return (registers.rbp & 0xFFFF) + adjust
|
|
if indirect == "bp":
|
|
return (registers.rbp & 0xFF) + adjust
|
|
if indirect == "rsi":
|
|
return registers.rsi + adjust
|
|
if indirect == "esi":
|
|
return (registers.rsi & 0xFFFFFFFF) + adjust
|
|
if indirect == "si":
|
|
return (registers.rsi & 0xFFFF) + adjust
|
|
if indirect == "si":
|
|
return (registers.rsi & 0xFF) + adjust
|
|
if indirect == "rdi":
|
|
return registers.rdi + adjust
|
|
if indirect == "edi":
|
|
return (registers.rdi & 0xFFFFFFFF) + adjust
|
|
if indirect == "di":
|
|
return (registers.rdi & 0xFFFF) + adjust
|
|
if indirect == "di":
|
|
return (registers.rdi & 0xFF) + adjust
|
|
|
|
raise Exception(f"Unsupported indirect address {indirect}!")
|
|
return None
|
|
|
|
|
|
def get_value(immediate: str) -> Optional[int]:
|
|
"""
|
|
Given an immediate value as formatted by the iced-x86 operand formatter,
|
|
resolve it to an immediate integer. If the value we receive is not
|
|
actually an immediate value, return None.
|
|
"""
|
|
|
|
immediate = sanitize(immediate)
|
|
|
|
if immediate[-1] == "h":
|
|
try:
|
|
return int(immediate[:-1], 16)
|
|
except Exception:
|
|
return None
|
|
|
|
try:
|
|
return int(immediate, 10)
|
|
except Exception:
|
|
return None
|
|
|
|
|
|
def get_size(operand: str) -> Optional[int]:
|
|
"""
|
|
Given an operand as formatted by the iced-x86 operand formatter, return
|
|
the size in bytes that that operand represents in a load or store.
|
|
Supports both registers and byte/word/dword/qword specifiers in front of
|
|
immediate values and indirect memory references.
|
|
"""
|
|
|
|
if operand in {'rax', 'rbx', 'rcx', 'rdx', 'rsp', 'rbp', 'rsi', 'rdi'}:
|
|
return 8
|
|
if operand in {'eax', 'ebx', 'ecx', 'edx', 'esp', 'ebp', 'esi', 'edi'}:
|
|
return 4
|
|
if operand in {'ax', 'bx', 'cx', 'dx', 'sp', 'bp', 'si', 'di'}:
|
|
return 2
|
|
if operand in {'ah', 'al', 'bh', 'bl', 'ch', 'cl', 'dh', 'dl', 'spl', 'bpl', 'sil', 'dil'}:
|
|
return 1
|
|
|
|
if operand[:5] == "byte ":
|
|
return 1
|
|
|
|
if operand[:5] == "word ":
|
|
return 2
|
|
|
|
if operand[:6] == "dword ":
|
|
return 4
|
|
|
|
if operand[:6] == "qword ":
|
|
return 8
|
|
|
|
return None
|
|
|
|
|
|
def assign(registers: Registers, memory: Memory, size: int, loc: str, value: int) -> None:
|
|
"""
|
|
Given the registers and memory of our emulator, the size of the operation
|
|
performed, the location to assign to and the value we should assign,
|
|
compute where the assignment should happen and then execute it.
|
|
"""
|
|
|
|
address = get_address(registers, loc)
|
|
if address is not None:
|
|
if size == 1:
|
|
data = struct.pack("<B", value)
|
|
elif size == 2:
|
|
data = struct.pack("<H", value)
|
|
elif size == 4:
|
|
data = struct.pack("<I", value)
|
|
elif size == 8:
|
|
data = struct.pack("<Q", value)
|
|
else:
|
|
raise Exception(f"Unsupported size {size} for memory assign!")
|
|
memory.store(address, data)
|
|
return
|
|
|
|
if loc == "rax":
|
|
registers.rax = value
|
|
return
|
|
|
|
if loc == "rbx":
|
|
registers.rbx = value
|
|
return
|
|
|
|
if loc == "rcx":
|
|
registers.rcx = value
|
|
return
|
|
|
|
if loc == "rdx":
|
|
registers.rdx = value
|
|
return
|
|
|
|
if loc == "rsp":
|
|
registers.rsp = value
|
|
return
|
|
|
|
if loc == "rbp":
|
|
registers.rbp = value
|
|
return
|
|
|
|
if loc == "rsi":
|
|
registers.rsi = value
|
|
return
|
|
|
|
if loc == "rdi":
|
|
registers.rdi = value
|
|
return
|
|
|
|
if loc == "eax":
|
|
registers.rax = (registers.rax & 0xFFFFFFFF00000000) | (value & 0xFFFFFFFF)
|
|
return
|
|
|
|
if loc == "ebx":
|
|
registers.rbx = (registers.rbx & 0xFFFFFFFF00000000) | (value & 0xFFFFFFFF)
|
|
return
|
|
|
|
if loc == "ecx":
|
|
registers.rcx = (registers.rcx & 0xFFFFFFFF00000000) | (value & 0xFFFFFFFF)
|
|
return
|
|
|
|
if loc == "edx":
|
|
registers.rdx = (registers.rdx & 0xFFFFFFFF00000000) | (value & 0xFFFFFFFF)
|
|
return
|
|
|
|
if loc == "esp":
|
|
registers.rsp = (registers.rsp & 0xFFFFFFFF00000000) | (value & 0xFFFFFFFF)
|
|
return
|
|
|
|
if loc == "ebp":
|
|
registers.rbp = (registers.rbp & 0xFFFFFFFF00000000) | (value & 0xFFFFFFFF)
|
|
return
|
|
|
|
if loc == "esi":
|
|
registers.rsi = (registers.rsi & 0xFFFFFFFF00000000) | (value & 0xFFFFFFFF)
|
|
return
|
|
|
|
if loc == "edi":
|
|
registers.rdi = (registers.rdi & 0xFFFFFFFF00000000) | (value & 0xFFFFFFFF)
|
|
return
|
|
|
|
if loc == "ax":
|
|
registers.rax = (registers.rax & 0xFFFFFFFFFFFF0000) | (value & 0xFFFF)
|
|
return
|
|
|
|
if loc == "bx":
|
|
registers.rbx = (registers.rbx & 0xFFFFFFFFFFFF0000) | (value & 0xFFFF)
|
|
return
|
|
|
|
if loc == "cx":
|
|
registers.rcx = (registers.rcx & 0xFFFFFFFFFFFF0000) | (value & 0xFFFF)
|
|
return
|
|
|
|
if loc == "dx":
|
|
registers.rdx = (registers.rdx & 0xFFFFFFFFFFFF0000) | (value & 0xFFFF)
|
|
return
|
|
|
|
if loc == "sp":
|
|
registers.rsp = (registers.rsp & 0xFFFFFFFFFFFF0000) | (value & 0xFFFF)
|
|
return
|
|
|
|
if loc == "bp":
|
|
registers.rbp = (registers.rbp & 0xFFFFFFFFFFFF0000) | (value & 0xFFFF)
|
|
return
|
|
|
|
if loc == "si":
|
|
registers.rsi = (registers.rsi & 0xFFFFFFFFFFFF0000) | (value & 0xFFFF)
|
|
return
|
|
|
|
if loc == "di":
|
|
registers.rdi = (registers.rdi & 0xFFFFFFFFFFFF0000) | (value & 0xFFFF)
|
|
return
|
|
|
|
if loc == "ah":
|
|
registers.rax = (registers.rax & 0xFFFFFFFFFFFF00FF) | ((value & 0xFF) << 8)
|
|
return
|
|
|
|
if loc == "al":
|
|
registers.rax = (registers.rax & 0xFFFFFFFFFFFFFF00) | (value & 0xFF)
|
|
return
|
|
|
|
if loc == "bh":
|
|
registers.rbx = (registers.rbx & 0xFFFFFFFFFFFF00FF) | ((value & 0xFF) << 8)
|
|
return
|
|
|
|
if loc == "bl":
|
|
registers.rbx = (registers.rbx & 0xFFFFFFFFFFFFFF00) | (value & 0xFF)
|
|
return
|
|
|
|
if loc == "ch":
|
|
registers.rcx = (registers.rcx & 0xFFFFFFFFFFFF00FF) | ((value & 0xFF) << 8)
|
|
return
|
|
|
|
if loc == "cl":
|
|
registers.rcx = (registers.rcx & 0xFFFFFFFFFFFFFF00) | (value & 0xFF)
|
|
return
|
|
|
|
if loc == "dh":
|
|
registers.rdx = (registers.rdx & 0xFFFFFFFFFFFF00FF) | ((value & 0xFF) << 8)
|
|
return
|
|
|
|
if loc == "dl":
|
|
registers.rdx = (registers.rdx & 0xFFFFFFFFFFFFFF00) | (value & 0xFF)
|
|
return
|
|
|
|
if loc == "spl":
|
|
registers.rsp = (registers.rsp & 0xFFFFFFFFFFFFFF00) | (value & 0xFF)
|
|
return
|
|
|
|
if loc == "bpl":
|
|
registers.rbp = (registers.rbp & 0xFFFFFFFFFFFFFF00) | (value & 0xFF)
|
|
return
|
|
|
|
if loc == "sil":
|
|
registers.rsi = (registers.rsi & 0xFFFFFFFFFFFFFF00) | (value & 0xFF)
|
|
return
|
|
|
|
if loc == "dil":
|
|
registers.rdi = (registers.rdi & 0xFFFFFFFFFFFFFF00) | (value & 0xFF)
|
|
return
|
|
|
|
raise Exception(f"Unsupported destination {loc} for assign!")
|
|
|
|
|
|
def fetch(registers: Registers, memory: Memory, size: int, loc: str) -> int:
|
|
"""
|
|
Given the registers and memory of our emulator, the size of the operation
|
|
performed and the location to fetch from, compute where the fetch should
|
|
happen and then execute it, returning the results of the fetch.
|
|
"""
|
|
|
|
address = get_address(registers, loc)
|
|
if address is not None:
|
|
if size == 1:
|
|
return struct.unpack("<B", memory.load(address, size))[0]
|
|
elif size == 2:
|
|
return struct.unpack("<H", memory.load(address, size))[0]
|
|
elif size == 4:
|
|
return struct.unpack("<I", memory.load(address, size))[0]
|
|
elif size == 8:
|
|
return struct.unpack("<Q", memory.load(address, size))[0]
|
|
else:
|
|
raise Exception(f"Unsupported size {size} for memory fetch!")
|
|
|
|
immediate = get_value(loc)
|
|
if immediate is not None:
|
|
if size == 1:
|
|
return immediate & 0xFF
|
|
if size == 2:
|
|
return immediate & 0xFFFF
|
|
if size == 4:
|
|
return immediate & 0xFFFFFFFF
|
|
if size == 8:
|
|
return immediate
|
|
raise Exception(f"Unsupported size {size} for immediate fetch!")
|
|
|
|
if loc == "rax":
|
|
return registers.rax
|
|
|
|
if loc == "rbx":
|
|
return registers.rbx
|
|
|
|
if loc == "rcx":
|
|
return registers.rcx
|
|
|
|
if loc == "rdx":
|
|
return registers.rdx
|
|
|
|
if loc == "rsi":
|
|
return registers.rsi
|
|
|
|
if loc == "rdi":
|
|
return registers.rdi
|
|
|
|
if loc == "rsp":
|
|
return registers.rsp
|
|
|
|
if loc == "rbp":
|
|
return registers.rbp
|
|
|
|
if loc == "eax":
|
|
return registers.rax & 0xFFFFFFFF
|
|
|
|
if loc == "ebx":
|
|
return registers.rbx & 0xFFFFFFFF
|
|
|
|
if loc == "ecx":
|
|
return registers.rcx & 0xFFFFFFFF
|
|
|
|
if loc == "edx":
|
|
return registers.rdx & 0xFFFFFFFF
|
|
|
|
if loc == "esi":
|
|
return registers.rsi & 0xFFFFFFFF
|
|
|
|
if loc == "edi":
|
|
return registers.rdi & 0xFFFFFFFF
|
|
|
|
if loc == "ebp":
|
|
return registers.rbp & 0xFFFFFFFF
|
|
|
|
if loc == "esp":
|
|
return registers.rsp & 0xFFFFFFFF
|
|
|
|
if loc == "ax":
|
|
return registers.rax & 0xFFFF
|
|
|
|
if loc == "bx":
|
|
return registers.rbx & 0xFFFF
|
|
|
|
if loc == "cx":
|
|
return registers.rcx & 0xFFFF
|
|
|
|
if loc == "dx":
|
|
return registers.rdx & 0xFFFF
|
|
|
|
if loc == "si":
|
|
return registers.rsi & 0xFFFF
|
|
|
|
if loc == "di":
|
|
return registers.rdi & 0xFFFF
|
|
|
|
if loc == "bp":
|
|
return registers.rbp & 0xFFFF
|
|
|
|
if loc == "sp":
|
|
return registers.rsp & 0xFFFF
|
|
|
|
if loc == "ah":
|
|
return (registers.rax & 0xFF00) >> 8
|
|
|
|
if loc == "al":
|
|
return registers.rax & 0xFF
|
|
|
|
if loc == "bh":
|
|
return (registers.rbx & 0xFF00) >> 8
|
|
|
|
if loc == "bl":
|
|
return registers.rbx & 0xFF
|
|
|
|
if loc == "ch":
|
|
return (registers.rcx & 0xFF00) >> 8
|
|
|
|
if loc == "cl":
|
|
return registers.rcx & 0xFF
|
|
|
|
if loc == "dh":
|
|
return (registers.rdx & 0xFF00) >> 8
|
|
|
|
if loc == "dl":
|
|
return registers.rdx & 0xFF
|
|
|
|
if loc == "spl":
|
|
return registers.rsp & 0xFF
|
|
|
|
if loc == "bpl":
|
|
return registers.rbp & 0xFF
|
|
|
|
if loc == "sil":
|
|
return registers.rsi & 0xFF
|
|
|
|
if loc == "dil":
|
|
return registers.rdi & 0xFF
|
|
|
|
raise Exception(f"Unsupported source {loc} for fetch!")
|