-
-
Save bruce30262/1f4ec443c82eb3587440877aa811c767 to your computer and use it in GitHub Desktop.
[flareon2018 level12] tiny disassembler for RSSB VM ( edit: I thought it was a subleq2 VM, but its RSSB instead )
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#!/usr/bin/env python | |
# -*- coding: utf-8 -*- | |
from pwn import * | |
import numpy | |
from collections import OrderedDict | |
import json | |
import inst2 | |
_120d = 0 | |
with open("./dump1", "rb") as f: | |
data = f.read() | |
assert len(data) == 0x8400 | |
code = dict() | |
def Word(addr): | |
global data | |
return u16(data[addr:addr+2:]) | |
def patch_word(addr, d): | |
global data | |
tmp = list(data) | |
d1 = d & 0xff | |
d2 = (d>>8)&0xff; | |
tmp[addr] = chr(d1) | |
tmp[addr+1] = chr(d2) | |
data = ''.join(tmp) | |
def subleq2(): | |
j = dict() | |
_120f = Word(0x120f) | |
cur_addr = (((0x7f6+ _120f )<<1)+0x223)&0xffff | |
_1201 = Word(cur_addr) | |
if _1201 == 0xffff: | |
_120f += 1 | |
patch_word(0x120f, _120f) | |
return | |
cur = (((0x7f6+ _1201 )<<1)+0x223)&0xffff | |
_120b = Word(cur) | |
j['op1'] = cur | |
_11ff = numpy.int16((_120b - Word(0x1211))) | |
patch_word(0x1211, _11ff) # 0x1211 = acc | |
s = "{:#x}: ".format(cur_addr) | |
s += "subleq2 [{:#x}]".format(cur) | |
if _11ff < 0: | |
_120f += 2 | |
s += " [{:#x}]".format(cur+2) | |
j['op2'] = cur+2 | |
else: | |
_120f += 1 | |
j['asm'] = s | |
code[cur_addr] = json.dumps(j) | |
patch_word(0x120f, _120f) | |
return s | |
def get_inst(): | |
while True: | |
_120f = Word(0x120f) | |
if _120f >= 0x2b57: | |
return | |
tmp = Word((((0x7f6+ _120f )<<1)+0x223)&0xffff) | |
if tmp == -2: | |
return | |
d = subleq2() | |
if d: | |
pass | |
#print hex(Word(0x120f)) | |
#print d | |
# starting point, might need to change in order to disassemble the whole thing | |
patch_word(0x120f, 0x15b) | |
patch_word(0x120d, 0x15b) | |
try: | |
get_inst() | |
except: | |
pass | |
#exit(0) | |
od = OrderedDict(sorted(code.items())) | |
dis = [] | |
black = [] | |
for pos, code in od.iteritems(): | |
if pos not in black: | |
dis.append((pos, code)) | |
token, rev_token = dict(), dict() | |
cur_token = None | |
Z = 0x1213 | |
acc = 0x1211 | |
pc = 0x120f | |
def trans(code): | |
def get_token(op): | |
global token, cur_token, rev_token | |
ret = None | |
if op == Z: | |
return hex(Z) | |
if op == acc: | |
return hex(acc) | |
if op == pc: | |
return hex(pc) | |
if op not in token: | |
ret = chr(cur_token) | |
token[op] = ret | |
rev_token[ret] = op | |
cur_token += 1 | |
else: | |
ret = token[op] | |
return ret | |
tk2 = None | |
tk1 = get_token(code["op1"]) | |
return tk1 | |
now = 0 | |
while now < len(dis): | |
matched = False | |
for ins in inst2.instruction: # traverse all instructions | |
sz = ins.sz | |
token.clear() | |
rev_token.clear() | |
cur_token = ord('a') | |
patt = [] | |
if now+sz-1 >= len(dis): continue | |
for idx in xrange(sz): | |
code = json.loads(dis[now+idx][1]) | |
patt.append(trans(code)) | |
if (ins.check(patt)): | |
print("{:#x}: {}".format(dis[now][0], ins.get_inst(rev_token, data))) | |
matched = True | |
now += sz | |
break | |
if not matched: | |
print(json.loads(dis[now][1])["asm"]) | |
now += 1 | |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#!/usr/bin/env python | |
# -*- coding: utf-8 -*- | |
from pwn import * | |
a = "a" | |
Z = "0x1213" | |
acc = "0x1211" | |
pc = "0x120f" | |
b = "b" | |
def Word(addr, data): | |
return u16(data[addr:addr+2:]) | |
class Inst(object): | |
def __init__(self, name, patt, sz): | |
""" | |
name: instruction name | |
patt: subleq pattern ( an array ) | |
sz: subleq instruction number | |
""" | |
self.name = name | |
self.patt = patt | |
self.sz = sz | |
def check(self, input_patt): | |
""" | |
check if a input pattern ( an array ) equals this instruction | |
""" | |
res = input_patt == self.patt | |
#print input_patt | |
#print self.patt | |
return res | |
class Jmp(Inst): | |
def __init__(self, patt): | |
super(Jmp, self).__init__("JMP", patt, 5) | |
def get_inst(self, *args): | |
rev_token = args[0] | |
data = args[1] | |
jmp_addr = rev_token["a"] | |
return "JMP $+{}".format(Word(jmp_addr, data)) | |
class Move(Inst): | |
def __init__(self, patt): | |
super(Move, self).__init__("MOV", patt, 10) | |
def get_inst(self, *args): | |
rev_token = args[0] | |
data = args[1] | |
dst = rev_token["a"] | |
src = rev_token["b"] | |
return "MOV [{:#x}], [{:#x}] ; {:#x}".format(dst, src, Word(src, data)) | |
class Add(Inst): | |
def __init__(self, patt): | |
super(Add, self).__init__("ADD", patt, 4) | |
def get_inst(self, *args): | |
rev_token = args[0] | |
data = args[1] | |
dst = rev_token["b"] | |
src = rev_token["a"] | |
return "ADD [{:#x}], [{:#x}] ; {:#x}".format(dst, src, Word(src, data)) | |
class Sub(Inst): | |
def __init__(self, patt): | |
super(Sub, self).__init__("SUB", patt, 5) | |
def get_inst(self, *args): | |
rev_token = args[0] | |
data = args[1] | |
dst = rev_token["b"] | |
src = rev_token["a"] | |
return "SUB [{:#x}], [{:#x}] ; {:#x}".format(dst, src, Word(src, data)) | |
class Clr(Inst): | |
def __init__(self, patt): | |
super(Clr, self).__init__("CLR", patt, 5) | |
def get_inst(self, *args): | |
rev_token = args[0] | |
dst = rev_token["a"] | |
return "CLR [{:#x}], [{:#x}]".format(dst, dst) | |
instruction = [] | |
instruction.append(Move([a, Z, Z, a, acc, b, Z, a, acc, acc])) | |
instruction.append(Add([a, Z, b, acc])) | |
instruction.append(Sub([a, Z, Z, b, acc])) | |
instruction.append(Clr([a, Z, Z, a, acc])) | |
instruction.append(Jmp([a, Z, pc, Z, acc])) | |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment