如何使用from_buffer_copy方法解码SMB原始

Question

当我尝试用 ctypes - From_buffer_copy解释SMB标头时，它会出现错误。我已经定义了字段(32个字节(，为什么Python向我显示 valueError：缓冲区大小太小(32而不是至少40个字节(

codelab：Mac OS X 64bit
codelab：linux

# python2.7 smbproto.py
Traceback (most recent call last):
  File "smbproto.py", line 77, in <module>
    SMB_HEADER(data)
  File "smbproto.py", line 39, in __new__
    return self.from_buffer_copy(buffer)
ValueError: Buffer size too small (32 instead of at least 40 bytes)

在这里代码。

#!/usr/bin/python
# -*- coding: utf-8 -*-
from ctypes import *
import logging

logging.basicConfig(level=logging.INFO)
log = logging.getLogger(__file__)

class SMB_HEADER(Structure):
  _fields_ = [
    ("server_component", c_uint32),
    ("smb_command", c_uint8),
    ("error_class", c_uint8),
    ("reserved1", c_uint8),
    ("error_code", c_uint16),
    ("flags", c_uint8),
    ("flags2", c_uint16),
    ("process_id_high", c_uint16),
    ("signature", c_uint64),
    ("reserved2", c_uint16),
    ("tree_id", c_uint16),
    ("process_id", c_uint16),
    ("user_id", c_uint16),
    ("multiplex_id", c_uint16)
  ]
  def __new__(self, buffer=None):
    return self.from_buffer_copy(buffer)
  def __init__(self, buffer):
    print("%04x" % self.server_component)
    print("%01x" % self.smb_command)
    print("%01x" % self.error_class)
    print("%01x" % self.reserved1)
    print("%02x" % self.error_code)
    print("%01x" % self.flags)
    print("%02x" % self.flags2)
    print("%02x" % self.process_id_high)
    print("%08x" % self.signature)
    print("%02x" % self.reserved2)
    print("%02x" % self.tree_id)
    print("%02x" % self.process_id)
    print("%02x" % self.user_id)
    print("%02x" % self.multiplex_id)

if __name__ == '__main__':
    data = (
        'xffSMB'   # server_component
        's'         # smb_command
        'x00'      # error_class
        'x00'      # reserved1
        'x00x00'  # error code
        'x98'      # flags
        'x01 '     # flags2
        'x00x00'  # process_id_high
        'x00x00x00x00x00x00x00x00'  # signature
        'x00x00'  # reserved2
        'x00x00'  # tree_id
        '/K'        # process_id
        'x00x10'  # user_id
        'xc5^'     # multiplex_id
    )
    SMB_HEADER(data)

Answer 1

您的标题结构太多：

 SMB_Header
   {
   UCHAR  Protocol[4];
   UCHAR  Command;
   SMB_ERROR Status;
   UCHAR  Flags;
   USHORT Flags2;
   USHORT PIDHigh;
   UCHAR  SecurityFeatures[8];
   USHORT Reserved;
   USHORT TID;
   USHORT PIDLow;
   USHORT UID;
   USHORT MID;
   }