patch/patch.py at master · DayJun/patch · GitHub

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frompwnimport*
fromcapstoneimport*
fromcapstone.x86importX86_INS_PUSH
importlief
importstruct
importos
importargparse
fromshellcodeimportmyShellCraft

classELFPatchUtils():
def__init__(self, binary):
self.e=lief.parse(binary)
self.name=binary
self.elf=ELF(binary, checksec=False)
self.originEntryPoint=self.e.entrypoint
self.modifiedPtr=0

defaddDataSegment(self, size):
segment_add=lief.ELF.Segment()
segment_add.type=lief.ELF.SEGMENT_TYPES.LOAD
segment_add.alignment=8
segment_add.add(lief.ELF.SEGMENT_FLAGS.W)
segment_add.add(lief.ELF.SEGMENT_FLAGS.R)
segment_add.content= [0for_inrange(size)]
segment=self.e.add(segment_add, base=0x20000)
log.success("add data segment succeed!")
returnsegment

defaddHookSegment(self):
segment_add=lief.ELF.Segment()
segment_add.type=lief.ELF.SEGMENT_TYPES.LOAD
segment_add.alignment=8
segment_add.add(lief.ELF.SEGMENT_FLAGS.X)
segment_add.add(lief.ELF.SEGMENT_FLAGS.R)
segment_add.content= [0for_inrange(0x1000)]
segment=self.e.add(segment_add, base=0x10000)
log.success("add hook segment succeed!")
returnsegment

defgetLOADSegment(self):
forsegmentinself.e.segments:
ifsegment.type==lief.ELF.SEGMENT_TYPES.LOADandsegment.flags&lief.ELF.SEGMENT_FLAGS.X!=0:
returnsegment

defgetSectionByName(self, name):
forsectioninself.e.sections:
ifsection.name==name:
returnsection

defgetPltAddress(self, name, static=False, pltAddress=None):
ifname=='nop':
return0
ifnotstatic:
try:
returnself.elf.plt[name]
except:
log.warn("No %s function"%(name))
return0
else:
returnpltAddress[name]

defgenShellcode(self, shellcodeName, args=None):
ifself.e.header.identity_class==lief.ELF.ELF_CLASS.CLASS64:
context.arch='amd64'
init_asm=''
ifshellcodeName=='initLog':
init_asm=asm(myShellCraft.init_shellcode64[shellcodeName].format(hex(args[0]), hex(args[1])))
shellcode=init_asm
elifshellcodeName=='readLog':
shellcode=asm(myShellCraft.shellcode64[shellcodeName].format(hex(args[0]), hex(args[1]+0x8)))
elifshellcodeName=='__isoc99_scanfLog':
shellcode=asm(myShellCraft.shellcode64[shellcodeName].format(hex(args[0]), hex(args[1]+8)))


elifself.e.header.identity_class==lief.ELF.ELF_CLASS.CLASS32:
context.arch='i386'
init_asm=''
ifshellcodeName=='initLog':
init_asm=asm(myShellCraft.init_shellcode32[shellcodeName].format(hex(args[0]), hex(args[1])))
shellcode=init_asm
elifshellcodeName=='readLog':
shellcode=asm(myShellCraft.shellcode32[shellcodeName].format(hex(args[0]), hex(args[1]+0x8)))
elifshellcodeName=='__isoc99_scanfLog':
shellcode=asm(myShellCraft.shellcode32[shellcodeName].format(hex(args[0]), hex(args[1]+8)))
code= []
try:
foriinshellcode:
code.append(ord(i))
except:
raiseException("No such shellcode")
returncode, len(init_asm)
defgetFunctionAddress(self, func_name, static):
ifstaticisFalseorfunc_name=='nop':
ifnotself.e.is_pieorfunc_name=='nop':
func_plt_address=self.getPltAddress(func_name)
else:
func_plt_address=self.getPltAddress(func_name) -self.originEntryPoint+self.e.entrypoint
returnfunc_plt_address
else:
try:
returnfunc_name
except:
raiseException("With --static please enter address@shellcode")

defhookCallPlt(self, funcShellcodeName, isStatic, args=None):
data_segment_added=self.addDataSegment(0x100)
oldEntrypoint=self.e.entrypoint
segment_add=self.addHookSegment()
init_length=0
forfuncShellcodeinfuncShellcodeName:
func_name, shellcodeName=funcShellcode.split('@')
ifisStaticandfunc_name!='nop':
func_name=eval(func_name)
ifshellcodeNamein ['initLog', 'readLog', '__isoc99_scanfLog']:
shellcode, init_length=self.genShellcode(shellcodeName, [segment_add.virtual_address, data_segment_added.virtual_address])
else:
shellcode=args[func_name]
prevShellcode=segment_add.content[:self.modifiedPtr]
prevShellcode+=shellcode
shellcodeLength=len(shellcode)
segment_add.content=prevShellcode
ifinit_length!=0:
patch_address=segment_add.virtual_address+init_length-5
init_offset=self.e.entrypoint-patch_address-5
patched_code= [ord(i) foriin (myShellCraft.opcode['jmp_offset']+struct.pack('i', init_offset))]
self.e.patch_address(patch_address, patched_code)
elifshellcodeNamein ['__isoc99_scanfLog']:
patch_address=segment_add.virtual_address+self.modifiedPtr+shellcodeLength-5
ifisStatic:
#patch_offset = self.getPltAddress('__isoc99_scanfPlt', isStatic, args) - patch_address - 5
patch_offset=self.getPltAddress(shellcodeName, isStatic, args) -patch_address-5
else:
#patch_offset = self.getFunctionAddress('__isoc99_scanf', isStatic) - patch_address - 5
patch_offset=self.getFunctionAddress(func_name, isStatic) -patch_address-5
patched_code= [ord(i) foriin (myShellCraft.opcode['jmp_offset']+struct.pack('i', patch_offset))]
self.e.patch_address(patch_address, patched_code)
LOADSegment=self.getLOADSegment()
textSection=self.getSectionByName('.text')
code_offset=textSection.file_offset
func_plt_address=self.getFunctionAddress(func_name, isStatic)
iffunc_plt_address==0:
self.modifiedPtr+=shellcodeLength
continue
ifself.e.header.identity_class==lief.ELF.ELF_CLASS.CLASS64:
md=Cs(CS_ARCH_X86, CS_MODE_64)
elifself.e.header.identity_class==lief.ELF.ELF_CLASS.CLASS32:
md=Cs(CS_ARCH_X86, CS_MODE_32)
code=bytearray(textSection.content)
offset_need_to_modified= []
findFunctionFlag=0
ifnotisStatic:
foriinmd.disasm(code, LOADSegment.virtual_address+code_offset):
ifi.mnemonic=='call':
ifi.op_str.startswith('0x'):
call_address=int(i.op_str, 16)
ifcall_address==func_plt_addressorcall_address==func_plt_address+4:
findFunctionFlag=1
offset_need_to_modified.append(i.address)
else:
offset_need_to_modified= [iforiinfunc_name]
findFunctionFlag=1
iffindFunctionFlag==0:
raiseException("can not find target function!")
foraddressinoffset_need_to_modified:
ifnotself.e.is_pie:
modified_offset=address- (self.e.entrypoint&~0xfffff) -code_offset
else:
modified_offset=address
offset=segment_add.virtual_address+init_length+self.modifiedPtr-address-5
patched_code= [ord(i) foriin (myShellCraft.opcode['call_offset'] +struct.pack('i', offset))]
self.e.patch_address(address, patched_code)
log.success("patched 0x%x"%(address))
self.modifiedPtr+=shellcodeLength
ifisStatic:
LOADSegment.physical_size=self.e.header.program_header_offset+self.e.header.numberof_segments*self.e.header.program_header_size
LOADSegment.virtual_size=LOADSegment.physical_size
self.e.header.entrypoint=segment_add.virtual_address
log.success("new entrypoint: 0x%x"%(self.e.entrypoint))
outfile=self.name+'_patch'
self.e.write(outfile)
st=os.stat(outfile)
os.chmod(outfile, st.st_mode|0111)
log.success("patch succeed!")


if__name__=='__main__':
parser=argparse.ArgumentParser(description="AWD patch tool")
parser.add_argument("bin", help="/path/to/your/input binary")
parser.add_argument("-s", "--shellcode", action='append', default=[], help="choose shellcode", required=True)
parser.add_argument("--static", action='store_true', help="static mode")
parser.add_argument("-p", "--plt", help="plt address; Need with --static")
args=parser.parse_args()
elf=ELFPatchUtils(args.bin)
#elf.hookPlt(args.functions, args.shellcode)
ifnotargs.static:
shellcode= ['nop@initLog']
forsinargs.shellcode:
shellcode.append(s)
elf.hookCallPlt(shellcode, False)
elifargs.static:
shellcode= ['nop@initLog']
forsinargs.shellcode:
shellcode.append(s)
try:
plt=eval(args.plt)
except:
raiseException("args Error")
elf.hookCallPlt(shellcode, True, plt)