add inctf 2019 easy-vm

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nganhkhoa 2020-12-14 01:25:00 +07:00
commit b9492db703
3 changed files with 259 additions and 0 deletions

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2019/inctf/easy-vm/run.py Normal file
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from z3 import *
class Program:
def __init__(self):
raw_bytes = open('crackme.i', 'rb').read()[8:]
self.code = [ int.from_bytes(raw_bytes[i:i+8], byteorder='little') for i in range(0, len(raw_bytes), 8) ]
self.register = [0 for i in range(10)]
self.instruction = 0
self.data_10 = 0
self.data_6 = 0
self.data_4 = 0
self.data_7 = 0
self.data_8 = 0
self.data_3 = 0
self.data_5 = 0
self.data_11 = 0
self.data_12 = 0
self.code_data = [0 for i in range(10000)]
self.s = Solver()
self.flag_count = 0
self.vars = []
def decode(self, ins):
self.instruction = ins;
self.data_10 = ~(~ins | 0xF000FFFFFFFFFFFF) >> 52;
self.data_6 = (ins & (ins ^ 0xFFF0FFFFFFFFFFFF)) >> 48;
self.data_4 = (ins & (ins ^ 0xFFFF0FFFFFFFFFFF)) >> 44;
self.data_7 = (ins & (ins ^ 0xFFFFF0FFFFFFFFFF)) >> 40;
self.data_8 = ~(~ins | 0xFFFFFF0FFFFFFFFF) >> 36;
self.data_3 = ~(~ins | 0xFFFFFFF000FFFFFF) >> 24;
self.data_5 = ~(~ins | 0xFF000000);
self.data_11 = (~(~ins | 0xFFFFFFF000FFFFFF) >> 24) // 5;
if self.data_5 >= 0x10:
self.data_5 = int(hex(self.data_5)[-2:], 16)
return (~(~ins | 0xFFFFFFF000FFFFFF) >> 24) // 5;
def switch_code1(self):
data_3 = self.data_3
if data_3 == 10:
return self.add()
if data_3 == 11:
print("end routine")
return 1
if data_3 == 12:
return self.jump()
if data_3 == 13:
print("has_current_eip")
return 1
if data_3 == 14:
return self.foo7()
return 0
def switch_code2(self):
data_3 = self.data_3
data_4 = self.data_4
register = self.register
if data_3 == 0:
return self.load()
if data_3 == 1:
return self.save()
if data_3 == 2:
print("register[{}] = get_char()".format(data_4))
register[data_4] = Int('flag_{:>3}'.format(self.flag_count))
self.s.add(register[data_4] >= 0)
self.s.add(register[data_4] <= 255)
self.flag_count += 1
return 1
if data_3 == 3:
print("print register[{}] {}".format(data_4, chr(register[data_4])))
return 1
if data_3 == 4:
return self.mov()
return 0
def switch_code3(self):
data_3 = self.data_3
if data_3 == 5:
return self.cmp()
if data_3 == 6:
return self.foo1()
if data_3 == 7:
return self.mul()
if data_3 == 8:
return self.shift_left()
if data_3 == 9:
return self.shift_right()
return 0
def load(self):
data_6 = self.data_6
data_5 = self.data_5
data_4 = self.data_4
data_7 = self.data_7
register = self.register
code_data = self.code_data
if data_6 == 1:
print("code_data[{}] = register[{}]".format(data_5, data_4))
code_data[data_5] = register[data_4]
return 1
if data_6 == 2:
print("code_data[register[{}]] = register[{}]".format(data_7, data_4))
code_data[register[data_7]] = register[data_4]
return 1
return 0
def save(self):
data_6 = self.data_6
data_5 = self.data_5
data_4 = self.data_4
data_7 = self.data_7
register = self.register
code_data = self.code_data
if data_6 == 1:
print("register[{}] = code_data[{}]".format(data_4, data_5))
register[data_4] = code_data[data_5]
return 1
if data_6 == 2:
print("register[{}] = code_data[register[{}]]".format(data_4, data_7))
register[data_4] = code_data[register[data_7]]
return 1
return 0
def mov(self):
data_6 = self.data_6
data_5 = self.data_5
data_4 = self.data_4
data_7 = self.data_7
register = self.register
if data_6 == 1:
print("register[{}] = register[{}]".format(data_4, data_7))
register[data_4] = register[data_7]
return 1
if data_6 == 0:
print("register[{}] = {} = {}".format(
data_4, data_5, data_5.to_bytes(1, byteorder='little')
))
register[data_4] = data_5
return 1
return 0
def add(self):
data_4 = self.data_4
data_5 = self.data_5
data_7 = self.data_7
register = self.register
print("register[{}] = {} + register[{}]".format(data_4, data_5, data_7))
register[data_4] = register[data_7] + data_5
return 1
def jump(self):
data_10 = self.data_10
data_6 = self.data_6
data_5 = self.data_5
if data_6 == 0:
print("jump offset {}".format(data_5))
else:
print("jump {}".format(data_10))
return 1
def mul(self):
data_4 = self.data_4
data_7 = self.data_7
data_8 = self.data_8
print("register[{}] = register[{}] * register[{}]".format(data_4, data_8, data_7))
return 1
def foo1(self):
print("foo1")
data_4 = self.data_4
data_7 = self.data_7
data_8 = self.data_8
register = self.register
register[data_4] = ~register[data_8] & register[data_7] | ~register[data_7] & register[data_8]
return 1
def shift_left(self):
data_4 = self.data_4
data_5 = self.data_5
print("register[{}] <<= {}".format(data_4, data_5))
return 1
def shift_right(self):
data_4 = self.data_4
data_5 = self.data_5
print("register[{}] <<= {}".format(data_4, data_5))
return 1
def cmp(self):
data_4 = self.data_4
data_7 = self.data_7
data_6 = self.data_6
register = self.register
if data_6 == 0:
print("register[{}] != register[{}]".format(data_7, data_4))
print(register[data_4] == register[data_7])
self.s.add(register[data_4] == register[data_7])
return 1
if data_6 == 1:
print("register[{}] > register[{}]".format(data_7, data_4))
print(register[data_4] <= register[data_7])
self.s.add(register[data_4] <= register[data_7])
return 1
if data_6 == 2:
print("register[{}] < register[{}]".format(data_7, data_4))
print(register[data_4] >= register[data_7])
self.s.add(register[data_4] >= register[data_7])
return 1
return 0
def foo7(self):
print("foo7")
return 1
def run(self):
for i in range(len(self.code)):
ins = self.code[i]
self.decode(ins)
print("{}\t {} [{}][{}][{}]\t".format(i, hex(ins), self.data_11, self.data_3, self.data_6), end='')
data_11 = self.data_11
if data_11 == 0:
self.switch_code2()
elif data_11 == 1:
self.switch_code3()
elif data_11 == 2:
self.switch_code1()
else:
print("invalid code?")
self.s.check()
m = self.s.model()
for k, v in sorted([(k, m[k]) for k in m], key=lambda x: str(x[0])):
print(chr(v.as_long()), end='')
print()
program = Program()
program.run()