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| from pwn import *
ip = 300
reg=0
originalCode=b'\x00'*600+open('code.bin','rb').read()
CodeList=[]
assert(len(originalCode)%2==0)
for i in range(len(originalCode)//2):
CodeList.append(u16(originalCode[i*2:i*2+2]))
def rol(num):
assert(0<=num<=0xffff)
return ((num<<1)&0xffff)+(num>>15)
def rol_back(num):
assert(0<=num<=0xffff)
return (num>>1)+(num%2)*(1<<15)
def rev(num):
return (~num)&0xffff
def jmp(addr):
global ip
info(f'ip={hex(ip)}:set ip to {hex(addr)}')
if addr-ip>30 or addr-ip<0:
input(f"error at ip={hex(ip)}")
ip=addr
def pattern_nor_reg(code):
src0,src1,dst=code[0],code[1],code[2]
if dst!=7:
return -1
return [src0,src1]
def nor_reg_handler(result):
reg=0xffffffff
return f'reg=~(*({hex(result[0])})|*({hex(result[1])}))'
def pattern_not(code):
src0,src1,dst=code[0],code[1],code[2]
if src0!=src1:
return -1
return [src0,dst]
def not_handler(result):
return f'*({hex(result[1])})=~(*({hex(result[0])}))'
def pattern_load_reg(code):
src0,src1,dst=code[0],code[1],code[2]
if src0!=src1 or dst!=7:
return -1
return src0
def load_reg_handler(result):
reg=rev(CodeList[result])
return f'reg=~(*({hex(result)}))'
def pattern_save_reg(code):
src0,src1,dst=code[0],code[1],code[2]
if src0!=src1 or src0!=7:
return -1
return dst
def save_reg_handler(result):
global reg
global ip
if result==0:
jmp(reg)
info('regjump')
ip-=3
return
return f'*({hex(result)})=~reg'
def pattern_jmp(code):
addr=pattern_load_reg(code)
if addr==-1:
return -1
code=code[3:]
src0,src1,dst=code[0],code[1],code[2]
if src0==src1==7 and dst==0:
return addr
return -1
def jmp_handler(result):
jmp(CodeList[result])
def pattern_load_imm(code):
addr=pattern_jmp(code)
if addr==-1:
return -1
if not (CodeList[addr]-addr==2 and pattern_load_reg(code[8:])==addr+1):
return -1
return code[7]
def load_imm_handler(result):
global reg
reg=result
return f'reg={hex(result)}'
def pattern_put(code):
chraddr=pattern_load_reg(code)
if chraddr==-1:
return -1
code=code[3:]
pos=pattern_save_reg(code)
if pos!=3:
return -1
code=code[3:]
imm=pattern_load_imm(code)
if imm!=1:
return -1
code=code[11:]
pos=pattern_save_reg(code)
if pos!=4:
return -1
return chraddr
def put_handler(result):
return f"putchar('{chr(CodeList[result])}')"
def pattern_get(code):
imm=pattern_load_imm(code)
if imm!=1:
return -1
code=code[11:]
pos=pattern_save_reg(code)
if pos!=6:
return -1
code=code[3:]
pos=pattern_load_reg(code)
if pos!=5:
return -1
code=code[3:]
addr=pattern_save_reg(code)
if addr==-1:
return -1
return addr
def get_handler(result):
return f"*({hex(result)})=getchar()"
def pattern_load_mem(code):
addrsrc=pattern_load_reg(code)
code=code[3:]
addrdst=pattern_save_reg(code)
if addrsrc==-1 or addrdst==-1:
return -1
return [addrsrc,addrdst]
def load_mem_handler(result):
return f"*({hex(result[1])})={f'*({hex(result[0])})' if result[0]!=7 else 'reg'}"
def pattern_rol(code):
result=pattern_load_mem(code)
if result==-1:
return -1
if result[0]!=result[1]:
return -1
addr=result[0]
code=code[6:]
result=pattern_load_mem(code)
if result==-1:
return -1
if result[1]!=addr or result[0]!=1:
return -1
return addr
def pattern_rols(code):
global ip
i=1
addr0=pattern_rol(code)
if addr0==-1:
return -1
ip+=12
while True:
addr1=pattern_rol(CodeList[ip:])
if addr1==-1 or addr1!=addr0:
break
i+=1
ip+=12
addr0=addr1
return [addr0, i%16]
def rols_handler(result):
return f'rol(*({hex(result[0])}), {str(result[1])})'
patterns=[[pattern_rols,rols_handler,0],[pattern_get,get_handler,20],[pattern_put,put_handler,20],[pattern_load_imm,load_imm_handler,11],[pattern_jmp,jmp_handler,0],[pattern_load_mem,load_mem_handler,6],[pattern_load_reg,load_reg_handler,3],[pattern_save_reg,save_reg_handler,3],[pattern_not,not_handler,3],[pattern_nor_reg,nor_reg_handler,3]]
def disassemble():
global ip
ip=300
while ip<len(CodeList):
flag=0
for pattern in patterns:
result=pattern[0](CodeList[ip:])
if result!=-1:
dis=pattern[1](result)
if dis!=None:
print(f'{hex(ip)}:{dis}')
ip+=pattern[2]
flag=1
break
if flag==0:
input(f'unknown instruction at ip={hex(ip)}')
def solve1(pc,l):
global ip
ip=pc
diff=0x78e-0x689
for i in range(l):
for pattern in patterns:
result=pattern[0](CodeList[ip:])
if result!=-1:
dis=pattern[1](result)
if dis!=None:
dis=dis
break
print(chr(rol(CodeList[pattern_not(CodeList[ip:])[0]])),end='')
ip+=diff
def solve2(pc,l):
global ip
ip=pc
diff1=0xf41-0xefc
diff2=0xf8c-0xf41
for j in range(l):
result=pattern_not(CodeList[ip:])
num1=CodeList[result[0]]
ip+=diff1
result=pattern_not(CodeList[ip:])
num2=CodeList[result[0]]
ip+=diff2
for i in range(32,127):
if (rev(rev(num1)|i)|rev(rev(i)|num1)) == num2:
print(chr(i),end='')
def solve3(pc,l):
global ip
ip=pc
diff=0x138e-0x1337
for i in range(l):
for pattern in patterns:
result=pattern[0](CodeList[ip:])
if result!=-1:
dis=pattern[1](result)
if dis!=None:
dis=dis
break
print(chr(rol_back(CodeList[pattern_not(CodeList[ip:])[0]])),end='')
ip+=diff
solve1(0x689,9)
solve2(0xefc,2)
solve1(0x10d6,3)
solve3(0x1337,4)
solve2(0x1487,1)
solve3(0x1523,1)
solve1(0x1628,1)
solve2(0x1673,1)
solve1(0x17bd,1)
solve2(0x1808,1)
solve3(0x18a4,1)
solve1(0x19a9,1)
solve3(0x1a00,1)
solve2(0x1a4b,3)
solve1(0x1cb5,1)
solve2(0x1d00,1)
solve3(0x1d9c,1)
solve2(0x1de7,1)
solve3(0x1e83,1)
|