172 lines
4.7 KiB
Python
172 lines
4.7 KiB
Python
# Volatools Basic
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# Copyright (C) 2007 Komoku, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or (at
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# your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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# pylint: disable=invalid-name,missing-docstring
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"""
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@author: AAron Walters and Nick Petroni
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@license: GNU General Public License 2.0 or later
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@contact: awalters@komoku.com, npetroni@komoku.com
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@organization: Komoku, Inc.
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"""
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import struct
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builtin_types = {
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'int': (4, 'i'),
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'long': (4, 'i'),
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'unsigned long': (4, 'I'),
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'unsigned int': (4, 'I'),
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'address': (4, 'I'),
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'char': (1, 'c'),
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'unsigned char': (1, 'B'),
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'unsigned short': (2, 'H'),
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'short': (2, 'h'),
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'long long': (8, 'q'),
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'unsigned long long': (8, 'Q'),
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'pointer': (4, 'I'),
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}
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def obj_size(types, objname):
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if objname not in types:
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raise Exception('Invalid type %s not in types' % (objname))
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return types[objname][0]
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def builtin_size(builtin):
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if builtin not in builtin_types:
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raise Exception('Invalid built-in type %s' % (builtin))
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return builtin_types[builtin][0]
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def read_value(addr_space, value_type, vaddr):
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"""
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Read the low-level value for a built-in type.
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"""
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if value_type not in builtin_types:
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raise Exception('Invalid built-in type %s' % (value_type))
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type_unpack_char = builtin_types[value_type][1]
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type_size = builtin_types[value_type][0]
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buf = addr_space.read(vaddr, type_size)
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if buf is None:
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return None
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(val,) = struct.unpack(type_unpack_char, buf)
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return val
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def read_unicode_string(addr_space, types, member_list, vaddr):
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offset = 0
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if len(member_list) > 1:
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(offset, __) = get_obj_offset(types, member_list)
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buf = read_obj(addr_space, types, ['_UNICODE_STRING', 'Buffer'], vaddr + offset)
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length = read_obj(addr_space, types, ['_UNICODE_STRING', 'Length'], vaddr + offset)
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if length == 0x0:
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return ""
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if buf is None or length is None:
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return None
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readBuf = read_string(addr_space, types, ['char'], buf, length)
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if readBuf is None:
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return None
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try:
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readBuf = readBuf.decode('UTF-16').encode('ascii')
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except Exception: # pylint: disable=broad-except
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return None
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return readBuf
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def read_string(addr_space, types, member_list, vaddr, max_length=256):
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offset = 0
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if len(member_list) > 1:
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(offset, __) = get_obj_offset(types, member_list)
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val = addr_space.read(vaddr + offset, max_length)
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return val
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def read_null_string(addr_space, types, member_list, vaddr, max_length=256):
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string = read_string(addr_space, types, member_list, vaddr, max_length)
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if string is None:
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return None
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return string.split('\0', 1)[0]
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def get_obj_offset(types, member_list):
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"""
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Returns the (offset, type) pair for a given list
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"""
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member_list.reverse()
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current_type = member_list.pop()
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offset = 0
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while member_list:
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if current_type == 'array':
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current_type = member_dict[current_member][1][2][0]
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if current_type in builtin_types:
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current_type_size = builtin_size(current_type)
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else:
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current_type_size = obj_size(types, current_type)
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index = member_list.pop()
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offset += index * current_type_size
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continue
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elif current_type not in types:
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raise Exception('Invalid type ' + current_type)
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member_dict = types[current_type][1]
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current_member = member_list.pop()
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if current_member not in member_dict:
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raise Exception('Invalid member %s in type %s' % (current_member, current_type))
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offset += member_dict[current_member][0]
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current_type = member_dict[current_member][1][0]
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return (offset, current_type)
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def read_obj(addr_space, types, member_list, vaddr):
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"""
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Read the low-level value for some complex type's member.
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The type must have members.
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"""
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if len(member_list) < 2:
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raise Exception('Invalid type/member ' + str(member_list))
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(offset, current_type) = get_obj_offset(types, member_list)
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return read_value(addr_space, current_type, vaddr + offset)
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