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flare_emu.py
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flare_emu.py
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############################################
# Copyright (C) 2018 FireEye, Inc.
#
# Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
# http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-BSD-3-CLAUSE or
# https://opensource.org/licenses/BSD-3-Clause>, at your option. This file may not be
# copied, modified, or distributed except according to those terms.
#
# Author: James T. Bennett
#
# flare-emu combines Unicorn and a choice of binary analysis engine to provide emulation support for
# reverse engineers
# Currently supports 32-bit and 64-bit x86, ARM, and ARM64
# Dependencies:
# https://github.com/unicorn-engine/unicorn
############################################
from __future__ import print_function
import unicorn
import unicorn.x86_const
import unicorn.arm_const
import unicorn.arm64_const
from copy import deepcopy
import logging
import struct
import re
import flare_emu_hooks
import types
import sys
PAGESIZE = 0x1000
PAGEALIGNCHECK = 0xfff
X86NOP = b"\x90"
ARMTHUMBNOP = b"\x00\xbf"
ARMNOP = b"\x00\xf0\x20\xe3"
ARM64NOP = b"\x1f\x20\x03\xd5"
MAX_ALLOC_SIZE = 10 * 1024 * 1024
MAXCODEPATHS = 20
MAXNODESEARCH = 100000
try:
long # Python 2
except NameError:
long = int # Python 3
# parent class to provide binary analysis engine support for EmuHelper class
# subclassed by Radare2AnalysisHelper and IdaProAnalysisHelper
class AnalysisHelper(object):
def __init__(self):
self.o_reg = 1
self.o_mem = 2
self.o_phrase = 3
self.o_displ = 4
self.o_imm = 5
self.o_far = 6
self.o_near = 7
def getFuncStart(self, addr):
pass
def getFuncEnd(self, addr):
pass
def getFuncName(self, addr):
pass
def getMnem(self, addr):
pass
# gets address of last instruction in the basic block containing addr
def getBlockEndInsnAddr(self, addr):
pass
def skipJumpTable(self, addr):
pass
def getMinimumAddr(self):
pass
def getMaximumAddr(self):
pass
def getBytes(self, addr, size):
pass
def getCString(self, addr):
pass
def getOperand(self, addr, opndNum):
pass
def getWordValue(self, addr):
pass
def getDwordValue(self, addr):
pass
def getQWordValue(self, addr):
pass
def isThumbMode(self, addr):
pass
# for segment/section related functions, IDA Pro calls everything segments
# while Radare2 maintains the distinction. PE's do not have segments, but sections,
# while ELFs and Mach-Os have both. We will maintain the distinction when the underlying
# framework supports it.
def getSegmentName(self, addr):
pass
def getSegmentStart(self, addr):
pass
def getSegmentEnd(self, addr):
pass
# gets the number of defined bytes in the segment containing addr.
# used when loading the binary to determine how many bytes to copy
# to emulator memory from each segment, because IDA Pro may have
# undefined bytes.
def getSegmentDefinedSize(self, addr):
pass
def getSegmentSize(self, addr):
pass
def getSegments(self):
pass
def getSectionName(self, addr):
pass
def getSectionStart(self, addr):
pass
def getSectionEnd(self, addr):
pass
def getSectionSize(self, addr):
pass
def getSections(self):
pass
# gets disassembled instruction with names and comments as a string
def getDisasmLine(self, addr):
pass
def getName(self, addr):
pass
def getNameAddr(self, name):
pass
def getOpndType(self, addr, opndNum):
pass
def getOpndValue(self, addr, opndNum):
pass
def makeInsn(self, addr):
pass
def createFunction(self, addr):
pass
def getFlowChart(self, addr):
pass
def getSpDelta(self, addr):
pass
def getXrefsTo(self, addr):
pass
def getBlockByAddr(self, addr, flowchart):
pass
def getArch(self):
pass
def getBitness(self):
pass
def getFileType(self):
pass
def getInsnSize(self, addr):
pass
def isTerminatingBB(self, addr):
pass
def getTerminatingBBs(self, flowchart):
term_bbs = []
for bb in flowchart:
if self.isTerminatingBB(bb):
term_bbs.append(bb)
return term_bbs
def getStartBB(self, addr, flowchart):
funcStart = self.getFuncStart(addr)
for bb in flowchart:
if bb.start_ea == funcStart:
return bb
def getBlockIdByVA(self, targetVA, flowchart):
return self.getBlockByVA(targetVA, flowchart).id
def getBlockByVA(self, targetVA, flowchart):
for bb in flowchart:
if targetVA >= bb.start_ea and targetVA < bb.end_ea:
return bb
def getBlockById(self, id, flowchart):
for bb in flowchart:
if bb.id == id:
return bb
def skipJumpTable(self, addr):
pass
def normalizeFuncName(self, funcName, extra=False):
pass
def setName(self, addr, name, size=0):
pass
def setComment(self, addr, comment):
pass
class EmuHelper():
def __init__(self, verbose=0, emuHelper=None, samplePath=None):
self.verbose = verbose
self.logger = logging.getLogger(__name__)
self.stack = 0
self.stackSize = 0x2000
self.size_DWORD = 4
self.size_pointer = 0
self.callMnems = ["CALL", "BL", "BLX", "BLR",
"BLXEQ", "BLEQ", "BLREQ"]
self.paths = {}
self.filetype = "UNKNOWN"
self.uc = None
self.h_userhook = None
self.h_memaccesshook = None
self.h_codehook = None
self.h_memhook = None
self.h_inthook = None
self.enteredBlock = False
self.hookData = {}
if samplePath is not None:
try:
import flare_emu_radare
except Exception as e:
self.logger.error("error importing flare_emu_radare: %s" % e)
return
# copy Radare2AnalysisHelper to skip reanalyzing binary and save time
if emuHelper is not None:
self.analysisHelper = emuHelper.analysisHelper
self.analysisHelper.eh = self
else:
self.analysisHelper = flare_emu_radare.Radare2AnalysisHelper(samplePath, self)
self.analysisHelperFramework = "Radare2"
else:
try:
import flare_emu_ida
except:
self.logger.error("error importing flare_emu_ida: specify samplePath to use radare2 or run under IDA Pro 7+")
return
self.analysisHelper = flare_emu_ida.IdaProAnalysisHelper(self)
self.analysisHelperFramework = "IDA Pro"
import idaapi
self.initEmuHelper()
if emuHelper is not None:
self._cloneEmuMem(emuHelper)
else:
self.reloadBinary()
# startAddr: address to start emulation
# endAddr: address to end emulation, this instruction is not executed.
# if not provided, emulation stops when starting function is exited
# (function must end with a return instruction)
# registers: a dict whose keys are register names and values are
# register values, all unspecified registers will be initialized to 0
# stack: a list of values to be setup on the stack before emulation.
# if X86 you must account for SP+0 (return address).
# for the stack and registers parameters, specifying a string will
# allocate memory, write the string to it, and write a pointer to that
# memory in the specified register/arg
# instructionHook: instruction hook func that runs AFTER emulateRange's hook
# hookData: user-defined data to be made available in instruction hook
# function, care must be taken to not use key names already used by
# flare_emu in userData dictionary
# skipCalls: emulator will skip over call instructions and adjust the
# stack accordingly, defaults to True
# emulateRange will always skip over calls to empty memory
# callHook: callback function that will be called whenever the emulator
# encounters a "call" instruction. keep in mind your skipCalls value
# and that emulateRange will always skip over calls to empty memory
# memAccessHook: hook function that runs when the emulator encounters a
# memory read or write
# hookApis: set to False if you don't want flare-emu to emulate common
# runtime memory and string functions, defaults to True
# returns the emulation object in its state after the emulation completes
# strict: checks branch destinations to ensure the disassembler expects
# instructions, otherwise skips branch instruction. if disabled,
# will make code in disassembler as it emulates (DISABLE WITH CAUTION).
# enabled by default
# count: Value passed to unicorn's uc_emu_start to indicate max number of
# instructions to emulate, Defaults to 0 (all code available).
def emulateRange(self, startAddr, endAddr=None, registers=None, stack=None, instructionHook=None, callHook=None,
memAccessHook=None, hookData=None, skipCalls=True, hookApis=True, strict=True, count=0):
if registers is None:
registers = {}
if stack is None:
stack = []
userData = {"EmuHelper": self, "funcStart": self.analysisHelper.getFuncStart(startAddr),
"funcEnd": self.analysisHelper.getFuncEnd(startAddr), "skipCalls": skipCalls, "strict": strict,
"endAddr": endAddr, "callHook": callHook, "hookApis": hookApis, "count": count}
if hookData:
userData.update(hookData)
if userData["funcEnd"] is None:
userData["funcEnd"] = userData["endAddr"]
mu = self.uc
self._prepEmuContext(registers, stack)
self.resetEmuHooks()
self.h_codehook = mu.hook_add(
unicorn.UC_HOOK_CODE, self._emulateRangeCodeHook, userData)
if instructionHook:
self.h_userhook = mu.hook_add(unicorn.UC_HOOK_CODE, instructionHook, userData)
if memAccessHook:
self.h_memaccesshook = self.uc.hook_add(unicorn.UC_HOOK_MEM_READ | unicorn.UC_HOOK_MEM_WRITE,
memAccessHook, userData)
self.h_memhook = mu.hook_add(unicorn.UC_HOOK_MEM_READ_UNMAPPED | unicorn.UC_HOOK_MEM_WRITE_UNMAPPED |
unicorn.UC_HOOK_MEM_FETCH_UNMAPPED, self._hookMemInvalid, userData)
self.h_inthook = mu.hook_add(
unicorn.UC_HOOK_INTR, self._hookInterrupt, userData)
if self.arch == unicorn.UC_ARCH_ARM:
userData["changeThumbMode"] = True
mu.emu_start(startAddr, userData["funcEnd"], count=count)
self.hookData = userData
return mu
# call emulateRange using selected instructions in IDA Pro as start/end addresses
def emulateSelection(self, registers=None, stack=None, instructionHook=None, callHook=None,
memAccessHook=None, hookData=None, skipCalls=True, hookApis=True, count=0):
import idaapi
try:
selection = idaapi.read_selection()
except TypeError:
selection = idaapi.read_range_selection(None)
if selection[0]:
self.emulateRange(selection[1], selection[2], registers, stack, instructionHook,
callHook, memAccessHook, hookData, skipCalls, hookApis, count=count)
else:
self.logger.error("emulateSelection is only available for IDA Pro")
# target: finds first path through function to target using depth first
# search for each address in list, if a single address is specified,
# does so for each xref to target address
# emulates each target's function, forcing path to target, then
# executes callback function providing emu object and arguments
# instructionHook: user-defined instruction hook to run AFTER guidedHook that
# forces execution
# hookData: user-defined data to be made available in instruction hook
# function, care must be taken to not use key names already used by
# flare_emu in userData dictionary
# preEmuCallback: a callback that is called BEFORE each emulation run
# callHook: a callback that is called whenever the emulator encounters a
# "call" instruction. hook or no, after a call instruction, the
# program counter is advanced to the next instruction and the stack is
# automatically cleaned up
# resetEmuMem: if set to True, unmaps all allocated emulator memory and
# reloads the binary from the IDB into emulator memory before each
# emulation run. can significantly increase script run time, defaults
# to False
# hookApis: set to False if you don't want flare-emu to emulate common
# runtime memory and string functions, defaults to True
# memAccessHook: hook function that runs when the emulator encounters a
# memory read or write
def iterate(self, target, targetCallback, preEmuCallback=None, callHook=None, instructionHook=None,
hookData=None, resetEmuMem=False, hookApis=True, memAccessHook=None):
if target is None:
return
targetInfo = {}
if type(target) in [int, long]:
self.logger.debug("iterate target function: %s" %
self.hexString(target))
xrefs = self.analysisHelper.getXrefsTo(target)
for i, x in enumerate(xrefs):
# get unique functions from xrefs that we need to emulate
funcStart = self.analysisHelper.getFuncStart(x)
if funcStart == None:
continue
if self.analysisHelper.getMnem(x).upper() not in ["CALL", "JMP", "BL", "BLX", "B", "BLR"]:
continue
self.logger.debug("getting a path to %s, %d of %d" %
(self.hexString(x), i + 1, len(xrefs)))
flow, paths = self.getPath(x)
if flow is not None:
targetInfo[x] = (flow, paths)
elif isinstance(target, list):
for i, t in enumerate(target):
self.logger.debug("getting a path to %s, %d of %d" %
(self.hexString(t), i + 1, len(target)))
flow, paths = self.getPath(t)
if flow is not None:
targetInfo[t] = (flow, paths)
if len(targetInfo) <= 0:
self.logger.debug("no targets to iterate")
return
userData = {}
userData["targetInfo"] = targetInfo
userData["targetCallback"] = targetCallback
userData["callHook"] = callHook
userData["EmuHelper"] = self
userData["hookApis"] = hookApis
if hookData:
userData.update(hookData)
self.resetEmuHooks()
self.h_codehook = self.uc.hook_add(
unicorn.UC_HOOK_CODE, self._guidedHook, userData)
if instructionHook:
self.h_userhook = self.uc.hook_add(unicorn.UC_HOOK_CODE, instructionHook, userData)
if memAccessHook:
self.h_memaccesshook = self.uc.hook_add(unicorn.UC_HOOK_MEM_READ | unicorn.UC_HOOK_MEM_WRITE,
memAccessHook, userData)
self.h_memhook = self.uc.hook_add(unicorn.UC_HOOK_MEM_READ_UNMAPPED | unicorn.UC_HOOK_MEM_WRITE_UNMAPPED |
unicorn.UC_HOOK_MEM_FETCH_UNMAPPED, self._hookMemInvalid, userData)
self.h_inthook = self.uc.hook_add(
unicorn.UC_HOOK_INTR, self._hookInterrupt, userData)
self.blockIdx = 0
cnt = 1
# read targets from dict to go from higher to lower addresses
# this is done to optimize loop by allowing hook to check for and remove other targets visited en route to
# current target
prev_target_info_len = len(userData["targetInfo"])
while len(userData["targetInfo"]) > 0:
# Fixes potential edge-case for infinite loop where the target VAs are never reached
# and the length never decreases. This modification verifies that the target VAs
# are being deleted; otherwise, breaks out of the while loop.
if cnt > 1 and len(userData["targetInfo"]) == prev_target_info_len:
break
prev_target_info_len = len(userData["targetInfo"])
userData["targetVA"] = targetVA = sorted(
userData["targetInfo"].keys(), reverse=True)[0]
flow, paths = userData["targetInfo"][targetVA]
funcStart = flow[0][0]
self.pathIdx = 0
numTargets = len(userData["targetInfo"])
self.logger.debug("iterate run #%d, %d targets remaining: %s (%d paths)" % (
cnt, numTargets, self.hexString(targetVA), len(paths)))
cnt2 = 1
numPaths = len(paths)
for path in paths:
self.logger.debug("emulating path #%d of %d from %s to %s via basic blocks: %s" % (
cnt2, numPaths, self.hexString(funcStart), self.hexString(targetVA), repr(path)))
for reg in self.regs:
self.uc.reg_write(self.regs[reg], 0)
if resetEmuMem:
self.reloadBinary()
self.uc.reg_write(self.regs["sp"], self.stack)
self.enteredBlock = False
userData["visitedTargets"] = []
if preEmuCallback:
preEmuCallback(self, userData, funcStart)
if self.arch == unicorn.UC_ARCH_ARM:
userData["changeThumbMode"] = True
self.uc.emu_start(funcStart, self.analysisHelper.getFuncEnd(funcStart))
self.pathIdx += 1
self.blockIdx = 0
cnt2 += 1
# remove visited targets during this run from our dict
for addr in userData["visitedTargets"]:
del(userData["targetInfo"][addr])
cnt += 1
self.hookData = userData
# target: iterates paths through a function
# targetCallback: a callback that is called when target (function end)
# is hit, providing arguments and userData
# preEmuCallback: a callback that is called BEFORE each emulation run
# callHook: a callback that is called whenever the emulator encounters a
# "call" instruction. hook or no, after a call instruction, the
# program counter is advanced to the next instruction and the stack is
# automatically cleaned up
# instructionHook: user-defined instruction hook to run AFTER guidedHook that
# forces execution
# hookData: user-defined data to be made available in instruction hook
# function, care must be taken to not use key names already used by
# flare_emu in userData dictionary
# resetEmuMem: if set to True, unmaps all allocated emulator memory and
# reloads the binary from the IDB into emulator memory before each
# emulation run. can significantly increase script run time, defaults
# to False
# hookApis: set to False if you don't want flare-emu to emulate common
# runtime memory and string functions, defaults to True
# memAccessHook: hook function that runs when the emulator encounters a
# memory read or write
# maxPaths: maximum number of paths to discover and emulate for a function
# maxNodes: maximum number of nodes to go through before giving up
def iterateAllPaths(self, target, targetCallback, preEmuCallback=None, callHook=None, instructionHook=None,
hookData=None, resetEmuMem=False, hookApis=True, memAccessHook=None, maxPaths=MAXCODEPATHS,
maxNodes=MAXNODESEARCH):
flowchart = self.analysisHelper.getFlowChart(target)
# targets are all function ends
targets = [self.analysisHelper.getBlockEndInsnAddr(bb.start_ea, flowchart) for bb
in self.analysisHelper.getTerminatingBBs(flowchart)]
targetInfo = {}
for i, t in enumerate(targets):
self.logger.debug("getting paths to %s, %d of %d targets" %
(self.hexString(t), i + 1, len(targets)))
flow, paths = self.getPathsToTarget(t, maxPaths, maxNodes)
if flow and paths:
targetInfo[t] = (flow, paths)
if len(targetInfo) <= 0:
self.logger.debug("iterateAllPaths: no targets to iterate for %s" % self.hexString(target))
return
userData = {}
userData["targetInfo"] = targetInfo
userData["targetCallback"] = targetCallback
userData["callHook"] = callHook
userData["EmuHelper"] = self
userData["hookApis"] = hookApis
if hookData:
userData.update(hookData)
self.internalRun = False
self.resetEmuHooks()
self.h_codehook = self.uc.hook_add(
unicorn.UC_HOOK_CODE, self._guidedHook, userData)
if instructionHook:
self.h_userhook = self.uc.hook_add(unicorn.UC_HOOK_CODE, instructionHook, userData)
if memAccessHook:
self.h_memaccesshook = self.uc.hook_add(unicorn.UC_HOOK_MEM_READ | unicorn.UC_HOOK_MEM_WRITE,
memAccessHook, userData)
self.h_memhook = self.uc.hook_add(unicorn.UC_HOOK_MEM_READ_UNMAPPED | unicorn.UC_HOOK_MEM_WRITE_UNMAPPED |
unicorn.UC_HOOK_MEM_FETCH_UNMAPPED, self._hookMemInvalid, userData)
self.h_inthook = self.uc.hook_add(
unicorn.UC_HOOK_INTR, self._hookInterrupt, userData)
self.blockIdx = 0
cnt = 1
for targetVA in sorted(userData["targetInfo"].keys(), reverse=True):
userData["targetVA"] = targetVA
flow, paths = userData["targetInfo"][targetVA]
funcStart = flow[0][0]
self.pathIdx = 0
numTargets = len(userData["targetInfo"])
self.logger.debug("run #%d, %d targets remaining: %s (%d paths)" % (
cnt, numTargets, self.hexString(targetVA), len(paths)))
cnt2 = 1
numPaths = len(paths)
for path in paths:
self.logger.debug("emulating path #%d of %d from %s to %s via basic blocks: %s" % (
cnt2, numPaths, self.hexString(funcStart), self.hexString(targetVA), repr(path)))
for reg in self.regs:
self.uc.reg_write(self.regs[reg], 0)
if resetEmuMem:
self.reloadBinary()
self.uc.reg_write(self.regs["sp"], self.stack)
self.enteredBlock = False
userData["visitedTargets"] = []
if preEmuCallback:
preEmuCallback(self, userData, funcStart)
if self.arch == unicorn.UC_ARCH_ARM:
userData["changeThumbMode"] = True
self.uc.emu_start(funcStart, self.analysisHelper.getFuncEnd(funcStart))
self.pathIdx += 1
self.blockIdx = 0
cnt2 += 1
cnt += 1
self.hookData = userData
# simply emulates to the end of whatever bytes are provided
# these bytes are not loaded into IDB, only emulator memory
# analysisHelper APIs are not available for use in hooks here
def emulateBytes(self, bytes, registers=None, stack=None, baseAddr=0x400000, instructionHook=None,
memAccessHook=None, hookData=None):
if registers is None:
registers = {}
if stack is None:
stack = []
userData = {}
if hookData:
userData.update(hookData)
baseAddr = self.loadBytes(bytes, baseAddr)
endAddr = baseAddr + len(bytes)
userData["endAddr"] = endAddr
mu = self.uc
self._prepEmuContext(registers, stack)
self.resetEmuHooks()
self.h_codehook = mu.hook_add(
unicorn.UC_HOOK_CODE, self._emulateBytesCodeHook, userData)
if instructionHook:
self.h_userhook = mu.hook_add(unicorn.UC_HOOK_CODE, instructionHook, userData)
if memAccessHook:
self.h_memaccesshook = self.uc.hook_add(unicorn.UC_HOOK_MEM_READ | unicorn.UC_HOOK_MEM_WRITE,
memAccessHook, userData)
self.h_memhook = mu.hook_add(unicorn.UC_HOOK_MEM_READ_UNMAPPED | unicorn.UC_HOOK_MEM_WRITE_UNMAPPED |
unicorn.UC_HOOK_MEM_FETCH_UNMAPPED, self._hookMemInvalid, userData)
self.h_inthook = mu.hook_add(
unicorn.UC_HOOK_INTR, self._hookInterrupt, userData)
mu.emu_start(baseAddr, endAddr)
self.hookData = userData
return mu
# emulates from startAddr continually
# must specify conditions under which emulation is stopped such as the "count" param
# or making a call to eh.stopEmulation from one of your hooks
# startAddr: address to start emulation
# registers: a dict whose keys are register names and values are
# register values, all unspecified registers will be initialized to 0
# stack: a list of values to be setup on the stack before emulation.
# if X86 you must account for SP+0 (return address).
# for the stack and registers parameters, specifying a string will
# allocate memory, write the string to it, and write a pointer to that
# memory in the specified register/arg
# instructionHook: instruction hook func that runs AFTER emulateFrom's hook
# hookData: user-defined data to be made available in instruction hook
# function, care must be taken to not use key names already used by
# flare_emu in userData dictionary
# skipCalls: emulator will skip over call instructions and adjust the
# stack accordingly, defaults to True
# emulateFrom will always skip over calls to empty memory
# callHook: callback function that will be called whenever the emulator
# encounters a "call" instruction. keep in mind your skipCalls value
# and that emulateFrom will always skip over calls to empty memory
# memAccessHook: hook function that runs when the emulator encounters a
# memory read or write
# hookApis: set to False if you don't want flare-emu to emulate common
# runtime memory and string functions, defaults to True
# returns the emulation object in its state after the emulation completes
# strict: checks branch destinations to ensure the disassembler expects
# instructions, otherwise skips branch instruction. if disabled,
# will make code in disassembler as it emulates (DISABLE WITH CAUTION).
# enabled by default
# count: Value passed to unicorn's uc_emu_start to indicate max number of
# instructions to emulate, Defaults to 0 (all code available).
def emulateFrom(self, startAddr, registers=None, stack=None, instructionHook=None, callHook=None,
memAccessHook=None, hookData=None, skipCalls=True, hookApis=True, strict=True, count=0):
if registers is None:
registers = {}
if stack is None:
stack = []
userData = {"EmuHelper": self, "skipCalls": skipCalls, "callHook": callHook,
"hookApis": hookApis, "strict": strict, "count": count}
if hookData:
userData.update(hookData)
mu = self.uc
self._prepEmuContext(registers, stack)
self.resetEmuHooks()
self.h_codehook = mu.hook_add(
unicorn.UC_HOOK_CODE, self._emulateRangeCodeHook, userData)
if instructionHook:
self.h_userhook = mu.hook_add(unicorn.UC_HOOK_CODE, instructionHook, userData)
if memAccessHook:
self.h_memaccesshook = self.uc.hook_add(unicorn.UC_HOOK_MEM_READ | unicorn.UC_HOOK_MEM_WRITE,
memAccessHook, userData)
self.h_memhook = mu.hook_add(unicorn.UC_HOOK_MEM_READ_UNMAPPED | unicorn.UC_HOOK_MEM_WRITE_UNMAPPED |
unicorn.UC_HOOK_MEM_FETCH_UNMAPPED, self._hookMemInvalid, userData)
self.h_inthook = mu.hook_add(
unicorn.UC_HOOK_INTR, self._hookInterrupt, userData)
if self.arch == unicorn.UC_ARCH_ARM:
userData["changeThumbMode"] = True
mu.emu_start(startAddr, self.analysisHelper.getMaximumAddr(), count=count)
self.hookData = userData
return mu
def writeEmuMem(self, addr, data):
if isinstance(data, bytearray):
data = bytes(data)
if not isinstance(data, bytes):
self.logger.error("wrong type for writeEmuMem data, expects bytes or bytearray: %s" % type(data))
return
self.uc.mem_write(addr, data)
def hexString(self, va):
if va > 0xffffffff:
return "%016X" % va
else:
return "%08X" % va
def pageAlignUp(self, v):
if v & PAGEALIGNCHECK != 0:
v += PAGESIZE - (v % PAGESIZE)
return v
# determines if the instruction at addr is for returning from a function call
def isRetInstruction(self, addr):
if self.analysisHelper.getMnem(addr)[:3].lower() == "ret":
return True
if (self.analysisHelper.getMnem(addr).lower() in ["bx", "b"] and
self.analysisHelper.getOperand(addr, 0).lower() == "lr"):
return True
if (self.analysisHelper.getMnem(addr).lower() == "pop" and
"pc" in self.analysisHelper.getDisasmLine(addr).lower()):
return True
return False
# call from an emulation hook to skip the current instruction, moving pc to next instruction
# useAnalysisHelper option added to handle cases where IDA folds multiple instructions (Radare2 doesn't do this)
# do not call multiple times in a row, depends on userData being updated by hook
def skipInstruction(self, userData, useAnalysisHelper=False):
if self.arch == unicorn.UC_ARCH_ARM:
userData["changeThumbMode"] = True
if useAnalysisHelper:
self.uc.reg_write(self.regs["pc"],
userData["currAddr"] + self.analysisHelper.getInsnSize(userData["currAddr"]))
else:
self.uc.reg_write(
self.regs["pc"], userData["currAddr"] + userData["currAddrSize"])
# get SP delta value for next instruction to adjust stack accordingly since we are skipping
# this instruction
self.uc.reg_write(self.regs["sp"], self.getRegVal(
"sp") + self.analysisHelper.getSpDelta(userData["currAddr"] +
self.analysisHelper.getInsnSize(userData["currAddr"])))
# call from an emulation hook to change program counter
def changeProgramCounter(self, userData, newPC):
if self.arch == unicorn.UC_ARCH_ARM:
userData["changeThumbMode"] = True
self.uc.reg_write(self.regs["pc"], newPC)
# retrieves the value of a register, handling subregister addressing
def getRegVal(self, regName):
regVal = self.uc.reg_read(self.regs[regName])
# handle various subregister addressing
if self.arch == unicorn.UC_ARCH_X86:
if regName[:-1] in ["l", "b"]:
regVal = regVal & 0xFF
elif regName[:-1] == "h":
regVal = (regVal & 0xFF00) >> 8
elif len(regName) == 2 and regName[:-1] == "x":
regVal = regVal & 0xFFFF
elif regName[0] == "e":
regVal = regVal & 0xFFFFFFFF
elif regName[:-1] == "d":
regVal = regVal & 0xFFFFFFFF
elif regName[:-1] == "w":
regVal = regVal & 0xFFFF
elif self.arch == unicorn.UC_ARCH_ARM64:
if regName[0] == "W":
regVal = regVal & 0xFFFFFFFF
return regVal
def stopEmulation(self, userData):
self.enteredBlock = False
if "visitedTargets" in userData and userData["targetVA"] not in userData["visitedTargets"]:
userData["visitedTargets"].append(
userData["targetVA"])
self.uc.emu_stop()
def resetEmuHooks(self):
if self.uc is None:
self.logger.debug(
"resetEmuHooks: no hooks to reset, emulator has not been initialized yet")
return
if self.h_userhook:
self.uc.hook_del(self.h_userhook)
self.h_userhook = None
if self.h_memaccesshook:
self.uc.hook_del(self.h_memaccesshook)
self.h_memaccesshook = None
if self.h_codehook:
self.uc.hook_del(self.h_codehook)
self.h_codehook = None
if self.h_memhook:
self.uc.hook_del(self.h_memhook)
self.h_memhook = None
if self.h_inthook:
self.uc.hook_del(self.h_inthook)
self.h_inthook = None
def getHookData(self):
return self.hookData
# for debugging purposes
def getEmuState(self):
if self.arch == unicorn.UC_ARCH_X86:
if self.uc._mode == unicorn.UC_MODE_64:
out = "RAX: %016X\tRBX: %016X\n" % (self.uc.reg_read(
unicorn.x86_const.UC_X86_REG_RAX), self.uc.reg_read(unicorn.x86_const.UC_X86_REG_RBX))
out += "RCX: %016X\tRDX: %016X\n" % (self.uc.reg_read(
unicorn.x86_const.UC_X86_REG_RCX), self.uc.reg_read(unicorn.x86_const.UC_X86_REG_RDX))
out += "RDI: %016X\tRSI: %016X\n" % (self.uc.reg_read(
unicorn.x86_const.UC_X86_REG_RDI), self.uc.reg_read(unicorn.x86_const.UC_X86_REG_RSI))
out += "R8: %016X\tR9: %016X\n" % (self.uc.reg_read(
unicorn.x86_const.UC_X86_REG_R8), self.uc.reg_read(unicorn.x86_const.UC_X86_REG_R9))
out += "RBP: %016X\tRSP: %016X\n" % (self.uc.reg_read(
unicorn.x86_const.UC_X86_REG_RBP), self.uc.reg_read(unicorn.x86_const.UC_X86_REG_RSP))
out += "RIP: %016X\n" % (self.uc.reg_read(unicorn.x86_const.UC_X86_REG_RIP))
elif self.uc._mode == unicorn.UC_MODE_32:
out = "EAX: %016X\tEBX: %016X\n" % (self.uc.reg_read(
unicorn.x86_const.UC_X86_REG_EAX), self.uc.reg_read(unicorn.x86_const.UC_X86_REG_EBX))
out += "ECX: %016X\tEDX: %016X\n" % (self.uc.reg_read(
unicorn.x86_const.UC_X86_REG_ECX), self.uc.reg_read(unicorn.x86_const.UC_X86_REG_EDX))
out += "EDI: %016X\tESI: %016X\n" % (self.uc.reg_read(
unicorn.x86_const.UC_X86_REG_EDI), self.uc.reg_read(unicorn.x86_const.UC_X86_REG_ESI))
out += "EBP: %016X\tESP: %016X\n" % (self.uc.reg_read(
unicorn.x86_const.UC_X86_REG_EBP), self.uc.reg_read(unicorn.x86_const.UC_X86_REG_ESP))
out += "EIP: %016X\n" % (self.uc.reg_read(unicorn.x86_const.UC_X86_REG_EIP))
elif self.arch == unicorn.UC_ARCH_ARM64:
out = "X0: %016X\tX1: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X0), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X1))
out += "X2: %016X\tX3: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X2), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X3))
out += "X4: %016X\tX5: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X4), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X5))
out += "X6: %016X\tX7: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X6), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X7))
out += "X8: %016X\tX9: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X8), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X9))
out += "X10: %016X\tX11: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X10), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X11))
out += "X12: %016X\tX13: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X12), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X13))
out += "X14: %016X\tX15: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X14), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X15))
out += "X16: %016X\tX17: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X16), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X17))
out += "X18: %016X\tX19: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X18), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X19))
out += "X20: %016X\tX21: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X20), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X21))
out += "X22: %016X\tX23: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X22), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X23))
out += "X24: %016X\tX25: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X24), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X25))
out += "X26: %016X\tX27: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X26), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X27))
out += "X28: %016X\tX29: %016X\n" % (self.uc.reg_read(
unicorn.arm64_const.UC_ARM64_REG_X28), self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X29))
out += "X30: %016X\n" % (self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_X30))
out += "PC: %016X\n" % (self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_PC))
out += "SP: %016X\n" % (self.uc.reg_read(unicorn.arm64_const.UC_ARM64_REG_SP))
elif self.arch == unicorn.UC_ARCH_ARM:
out = "R0: %08X\tR1: %08X\n" % (self.uc.reg_read(
unicorn.arm_const.UC_ARM_REG_R0), self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R1))
out += "R2: %08X\tR3: %08X\n" % (self.uc.reg_read(
unicorn.arm_const.UC_ARM_REG_R2), self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R3))
out += "R4: %08X\tR5: %08X\n" % (self.uc.reg_read(
unicorn.arm_const.UC_ARM_REG_R4), self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R5))
out += "R6: %08X\tR7: %08X\n" % (self.uc.reg_read(
unicorn.arm_const.UC_ARM_REG_R6), self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R7))
out += "R8: %08X\tR9: %08X\n" % (self.uc.reg_read(
unicorn.arm_const.UC_ARM_REG_R8), self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R9))
out += "R10: %08X\tR11: %08X\n" % (self.uc.reg_read(
unicorn.arm_const.UC_ARM_REG_R10), self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R11))
out += "R12: %08X\tR13: %08X\n" % (self.uc.reg_read(
unicorn.arm_const.UC_ARM_REG_R12), self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R13))
out += "R14: %08X\tR15: %08X\n" % (self.uc.reg_read(
unicorn.arm_const.UC_ARM_REG_R14), self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R15))
out += "PC: %08X\n" % self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R15)
out += "SP: %08X\n" % self.uc.reg_read(unicorn.arm_const.UC_ARM_REG_R13)
else:
return ""
return out
# returns null-terminated string of bytes from the emulator's memory, starting at addr, do not necessarily need
# to be printable characters
def getEmuString(self, addr):
# return a bytearray object , if you want to get a str object ,you must decode it by latin1
out = bytearray()
while self.uc.mem_read(addr, 1) != b"\x00":
out += self.uc.mem_read(addr, 1)
addr += 1
return out
def getEmuWideString(self, addr):
# return a bytearray object , if you want to get a str object ,you must decode it by utf-16le
out = bytearray()
while self.uc.mem_read(addr, 2) != b"\x00\x00":
out += self.uc.mem_read(addr, 2)
addr += 2
return out
# returns a <size> bytearray of bytes read from <addr>
def getEmuBytes(self, addr, size):
return self.uc.mem_read(addr, size)
# reads pointer value in emulator's memory
def getEmuPtr(self, va):
return struct.unpack(self.pack_fmt, self.uc.mem_read(va, self.size_pointer))[0]
# writes a pointer value in emulator's memory
def writeEmuPtr(self, va, value):
self.writeEmuMem(va, struct.pack(self.pack_fmt, value))
# gets the signed integer value of the unsigned integer value given the bitness of the architecture
def getSignedValue(self, value):
return struct.unpack(self.pack_fmt_signed, struct.pack(self.pack_fmt, value))[0]
def pageAlign(self, addr):
return addr & 0xfffffffffffff000
# get first path to target found during exploration
def getPath(self, targetVA):
flowchart = self.analysisHelper.getFlowChart(targetVA)
target_bb = self.analysisHelper.getBlockByVA(targetVA, flowchart)
start_bb = self.analysisHelper.getStartBB(targetVA, flowchart)
if target_bb.id != 0:
if self.verbose > 0:
self.logger.debug("exploring function with %d blocks" % len(flowchart))
graph = self._explore(start_bb, target_bb)
if graph is None:
self.logger.debug(
"graph for target %s could not be traversed, skipping" % self.hexString(targetVA))
return None, None
if self.verbose > 0:
self.logger.debug("graph for target:\n%s" % repr(graph))
path = [0]
if not self._findPathFromGraph(path, graph, 0, target_bb.id):
self.logger.debug(
"path for target %s could not be discovered, skipping" % self.hexString(targetVA))
return None, None
else:
path = [0]
if self.verbose > 0:
self.logger.debug("code path to target: %s" % repr(path))
# create my own idaapi.FlowChart-like object to optimize calculating block end addrs
flow = {}
for bb in flowchart:
flow[bb.id] = (bb.start_ea, self.analysisHelper.getBlockEndInsnAddr(bb.start_ea, flowchart))
return flow, [path]
# get up to maxPaths path to target
# for some complex functions, may give up before finding a path
def getPathsToTarget(self, targetVA, maxPaths=MAXCODEPATHS, maxNodes=MAXNODESEARCH):
flowchart = self.analysisHelper.getFlowChart(targetVA)
target_bb = self.analysisHelper.getBlockByVA(targetVA, flowchart)
start_bb = self.analysisHelper.getStartBB(targetVA, flowchart)
if target_bb.id != 0:
if self.verbose > 0:
self.logger.debug("exploring function with %d blocks" % len(flowchart))
graph = self._explore(start_bb)
if graph is None:
self.logger.debug(
"graph for target %s could not be traversed, skipping" % self.hexString(targetVA))
return None, None
if self.verbose > 0:
self.logger.debug("graph for target:\n%s" % repr(graph))
path = [0]
paths = []
targets = [target_bb.id]
self._findPathsFromGraph(paths, path, graph, 0, targets, maxPaths, 0 , maxNodes)
if len(paths) == 0:
self.logger.debug(
"path for target %s could not be discovered, skipping" % self.hexString(targetVA))
return None, None
else:
paths = [[0]]
if self.verbose > 0:
self.logger.debug("code paths to target: %s" % repr(paths))
# create my own idaapi.FlowChart object so it can be pickled for debugging purposes
flow = {}
for bb in flowchart:
flow[bb.id] = (bb.start_ea, self.analysisHelper.getBlockEndInsnAddr(bb.start_ea, flowchart))
return flow, paths
# get up to maxPaths paths from function start to any terminating basic block
# for some complex functions, may give up before finding a path
def getPaths(self, fva, maxPaths=MAXCODEPATHS, maxNodes=MAXNODESEARCH):
flowchart = self.analysisHelper.getFlowChart(fva)
term_bbs_ids = [bb.id for bb in self.analysisHelper.getTerminatingBBs(flowchart)]
start_bb = self.analysisHelper.getStartBB(fva, flowchart)
if term_bbs_ids != [0]: