mirror of
https://github.com/fortra/impacket
synced 2026-06-08 14:15:13 +00:00
Martin Gallo
cd4fe47cfc
This was a pending change to: - Use the same tagline, copyright and license notice across files. - Remove authors' contacts that are no longer valid (due to affiliation changes). - Update repository location. - Update license file with missing licenses (althought those were already in source files). This doesn't include any change on the source code, nor any change on current copyright or licenses. Just formatting and phrasing to make our and distro's maintainers life easier.
662 lines
22 KiB
Python
662 lines
22 KiB
Python
# Impacket - Collection of Python classes for working with network protocols.
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#
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# SECUREAUTH LABS. Copyright (C) 2020 SecureAuth Corporation. All rights reserved.
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#
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# This software is provided under a slightly modified version
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# of the Apache Software License. See the accompanying LICENSE file
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# for more information.
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#
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from __future__ import division
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from __future__ import print_function
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from struct import pack, unpack, calcsize
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from six import b, PY3
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class Structure:
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""" sublcasses can define commonHdr and/or structure.
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each of them is an tuple of either two: (fieldName, format) or three: (fieldName, ':', class) fields.
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[it can't be a dictionary, because order is important]
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where format specifies how the data in the field will be converted to/from bytes (string)
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class is the class to use when unpacking ':' fields.
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each field can only contain one value (or an array of values for *)
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i.e. struct.pack('Hl',1,2) is valid, but format specifier 'Hl' is not (you must use 2 dfferent fields)
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format specifiers:
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specifiers from module pack can be used with the same format
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see struct.__doc__ (pack/unpack is finally called)
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x [padding byte]
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c [character]
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b [signed byte]
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B [unsigned byte]
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h [signed short]
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H [unsigned short]
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l [signed long]
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L [unsigned long]
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i [signed integer]
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I [unsigned integer]
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q [signed long long (quad)]
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Q [unsigned long long (quad)]
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s [string (array of chars), must be preceded with length in format specifier, padded with zeros]
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p [pascal string (includes byte count), must be preceded with length in format specifier, padded with zeros]
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f [float]
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d [double]
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= [native byte ordering, size and alignment]
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@ [native byte ordering, standard size and alignment]
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! [network byte ordering]
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< [little endian]
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> [big endian]
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usual printf like specifiers can be used (if started with %)
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[not recommended, there is no way to unpack this]
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%08x will output an 8 bytes hex
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%s will output a string
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%s\\x00 will output a NUL terminated string
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%d%d will output 2 decimal digits (against the very same specification of Structure)
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...
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some additional format specifiers:
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: just copy the bytes from the field into the output string (input may be string, other structure, or anything responding to __str__()) (for unpacking, all what's left is returned)
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z same as :, but adds a NUL byte at the end (asciiz) (for unpacking the first NUL byte is used as terminator) [asciiz string]
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u same as z, but adds two NUL bytes at the end (after padding to an even size with NULs). (same for unpacking) [unicode string]
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w DCE-RPC/NDR string (it's a macro for [ '<L=(len(field)+1)/2','"\\x00\\x00\\x00\\x00','<L=(len(field)+1)/2',':' ]
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?-field length of field named 'field', formatted as specified with ? ('?' may be '!H' for example). The input value overrides the real length
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?1*?2 array of elements. Each formatted as '?2', the number of elements in the array is stored as specified by '?1' (?1 is optional, or can also be a constant (number), for unpacking)
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'xxxx literal xxxx (field's value doesn't change the output. quotes must not be closed or escaped)
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"xxxx literal xxxx (field's value doesn't change the output. quotes must not be closed or escaped)
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_ will not pack the field. Accepts a third argument, which is an unpack code. See _Test_UnpackCode for an example
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?=packcode will evaluate packcode in the context of the structure, and pack the result as specified by ?. Unpacking is made plain
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?&fieldname "Address of field fieldname".
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For packing it will simply pack the id() of fieldname. Or use 0 if fieldname doesn't exists.
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For unpacking, it's used to know weather fieldname has to be unpacked or not, i.e. by adding a & field you turn another field (fieldname) in an optional field.
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"""
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commonHdr = ()
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structure = ()
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debug = 0
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def __init__(self, data = None, alignment = 0):
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if not hasattr(self, 'alignment'):
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self.alignment = alignment
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self.fields = {}
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self.rawData = data
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if data is not None:
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self.fromString(data)
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else:
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self.data = None
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@classmethod
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def fromFile(self, file):
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answer = self()
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answer.fromString(file.read(len(answer)))
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return answer
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def setAlignment(self, alignment):
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self.alignment = alignment
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def setData(self, data):
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self.data = data
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def packField(self, fieldName, format = None):
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if self.debug:
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print("packField( %s | %s )" % (fieldName, format))
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if format is None:
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format = self.formatForField(fieldName)
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if fieldName in self.fields:
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ans = self.pack(format, self.fields[fieldName], field = fieldName)
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else:
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ans = self.pack(format, None, field = fieldName)
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if self.debug:
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print("\tanswer %r" % ans)
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return ans
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def getData(self):
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if self.data is not None:
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return self.data
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data = bytes()
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for field in self.commonHdr+self.structure:
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try:
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data += self.packField(field[0], field[1])
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except Exception as e:
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if field[0] in self.fields:
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e.args += ("When packing field '%s | %s | %r' in %s" % (field[0], field[1], self[field[0]], self.__class__),)
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else:
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e.args += ("When packing field '%s | %s' in %s" % (field[0], field[1], self.__class__),)
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raise
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if self.alignment:
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if len(data) % self.alignment:
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data += (b'\x00'*self.alignment)[:-(len(data) % self.alignment)]
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#if len(data) % self.alignment: data += ('\x00'*self.alignment)[:-(len(data) % self.alignment)]
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return data
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def fromString(self, data):
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self.rawData = data
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for field in self.commonHdr+self.structure:
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if self.debug:
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print("fromString( %s | %s | %r )" % (field[0], field[1], data))
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size = self.calcUnpackSize(field[1], data, field[0])
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if self.debug:
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print(" size = %d" % size)
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dataClassOrCode = b
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if len(field) > 2:
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dataClassOrCode = field[2]
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try:
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self[field[0]] = self.unpack(field[1], data[:size], dataClassOrCode = dataClassOrCode, field = field[0])
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except Exception as e:
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e.args += ("When unpacking field '%s | %s | %r[:%d]'" % (field[0], field[1], data, size),)
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raise
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size = self.calcPackSize(field[1], self[field[0]], field[0])
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if self.alignment and size % self.alignment:
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size += self.alignment - (size % self.alignment)
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data = data[size:]
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return self
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def __setitem__(self, key, value):
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self.fields[key] = value
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self.data = None # force recompute
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def __getitem__(self, key):
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return self.fields[key]
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def __delitem__(self, key):
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del self.fields[key]
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def __str__(self):
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return self.getData()
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def __len__(self):
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# XXX: improve
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return len(self.getData())
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def pack(self, format, data, field = None):
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if self.debug:
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print(" pack( %s | %r | %s)" % (format, data, field))
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if field:
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addressField = self.findAddressFieldFor(field)
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if (addressField is not None) and (data is None):
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return b''
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# void specifier
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if format[:1] == '_':
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return b''
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# quote specifier
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if format[:1] == "'" or format[:1] == '"':
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return b(format[1:])
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# code specifier
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two = format.split('=')
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if len(two) >= 2:
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try:
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return self.pack(two[0], data)
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except:
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fields = {'self':self}
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fields.update(self.fields)
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return self.pack(two[0], eval(two[1], {}, fields))
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# address specifier
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two = format.split('&')
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if len(two) == 2:
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try:
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return self.pack(two[0], data)
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except:
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if (two[1] in self.fields) and (self[two[1]] is not None):
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return self.pack(two[0], id(self[two[1]]) & ((1<<(calcsize(two[0])*8))-1) )
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else:
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return self.pack(two[0], 0)
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# length specifier
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two = format.split('-')
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if len(two) == 2:
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try:
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return self.pack(two[0],data)
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except:
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return self.pack(two[0], self.calcPackFieldSize(two[1]))
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# array specifier
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two = format.split('*')
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if len(two) == 2:
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answer = bytes()
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for each in data:
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answer += self.pack(two[1], each)
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if two[0]:
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if two[0].isdigit():
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if int(two[0]) != len(data):
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raise Exception("Array field has a constant size, and it doesn't match the actual value")
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else:
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return self.pack(two[0], len(data))+answer
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return answer
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# "printf" string specifier
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if format[:1] == '%':
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# format string like specifier
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return b(format % data)
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# asciiz specifier
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if format[:1] == 'z':
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if isinstance(data,bytes):
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return data + b('\0')
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return bytes(b(data)+b('\0'))
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# unicode specifier
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if format[:1] == 'u':
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return bytes(data+b('\0\0') + (len(data) & 1 and b('\0') or b''))
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# DCE-RPC/NDR string specifier
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if format[:1] == 'w':
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if len(data) == 0:
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data = b('\0\0')
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elif len(data) % 2:
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data = b(data) + b('\0')
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l = pack('<L', len(data)//2)
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return b''.join([l, l, b('\0\0\0\0'), data])
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if data is None:
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raise Exception("Trying to pack None")
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# literal specifier
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if format[:1] == ':':
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if isinstance(data, Structure):
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return data.getData()
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# If we have an object that can serialize itself, go ahead
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elif hasattr(data, "getData"):
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return data.getData()
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elif isinstance(data, int):
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return bytes(data)
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elif isinstance(data, bytes) is not True:
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return bytes(b(data))
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else:
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return data
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if format[-1:] == 's':
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# Let's be sure we send the right type
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if isinstance(data, bytes) or isinstance(data, bytearray):
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return pack(format, data)
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else:
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return pack(format, b(data))
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# struct like specifier
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return pack(format, data)
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def unpack(self, format, data, dataClassOrCode = b, field = None):
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if self.debug:
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print(" unpack( %s | %r )" % (format, data))
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if field:
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addressField = self.findAddressFieldFor(field)
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if addressField is not None:
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if not self[addressField]:
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return
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# void specifier
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if format[:1] == '_':
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if dataClassOrCode != b:
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fields = {'self':self, 'inputDataLeft':data}
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fields.update(self.fields)
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return eval(dataClassOrCode, {}, fields)
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else:
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return None
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# quote specifier
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if format[:1] == "'" or format[:1] == '"':
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answer = format[1:]
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if b(answer) != data:
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raise Exception("Unpacked data doesn't match constant value '%r' should be '%r'" % (data, answer))
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return answer
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# address specifier
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two = format.split('&')
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if len(two) == 2:
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return self.unpack(two[0],data)
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# code specifier
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two = format.split('=')
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if len(two) >= 2:
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return self.unpack(two[0],data)
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# length specifier
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two = format.split('-')
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if len(two) == 2:
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return self.unpack(two[0],data)
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# array specifier
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two = format.split('*')
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if len(two) == 2:
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answer = []
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sofar = 0
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if two[0].isdigit():
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number = int(two[0])
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elif two[0]:
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sofar += self.calcUnpackSize(two[0], data)
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number = self.unpack(two[0], data[:sofar])
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else:
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number = -1
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while number and sofar < len(data):
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nsofar = sofar + self.calcUnpackSize(two[1],data[sofar:])
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answer.append(self.unpack(two[1], data[sofar:nsofar], dataClassOrCode))
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number -= 1
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sofar = nsofar
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return answer
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# "printf" string specifier
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if format[:1] == '%':
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# format string like specifier
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return format % data
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# asciiz specifier
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if format == 'z':
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if data[-1:] != b('\x00'):
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raise Exception("%s 'z' field is not NUL terminated: %r" % (field, data))
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if PY3:
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return data[:-1].decode('latin-1')
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else:
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return data[:-1]
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# unicode specifier
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if format == 'u':
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if data[-2:] != b('\x00\x00'):
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raise Exception("%s 'u' field is not NUL-NUL terminated: %r" % (field, data))
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return data[:-2] # remove trailing NUL
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# DCE-RPC/NDR string specifier
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if format == 'w':
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l = unpack('<L', data[:4])[0]
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return data[12:12+l*2]
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# literal specifier
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if format == ':':
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if isinstance(data, bytes) and dataClassOrCode is b:
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return data
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return dataClassOrCode(data)
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# struct like specifier
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return unpack(format, data)[0]
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def calcPackSize(self, format, data, field = None):
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# # print " calcPackSize %s:%r" % (format, data)
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if field:
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addressField = self.findAddressFieldFor(field)
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if addressField is not None:
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if not self[addressField]:
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return 0
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# void specifier
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if format[:1] == '_':
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return 0
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# quote specifier
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if format[:1] == "'" or format[:1] == '"':
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return len(format)-1
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# address specifier
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two = format.split('&')
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if len(two) == 2:
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return self.calcPackSize(two[0], data)
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# code specifier
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two = format.split('=')
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if len(two) >= 2:
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return self.calcPackSize(two[0], data)
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# length specifier
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two = format.split('-')
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if len(two) == 2:
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return self.calcPackSize(two[0], data)
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# array specifier
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two = format.split('*')
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if len(two) == 2:
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answer = 0
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if two[0].isdigit():
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if int(two[0]) != len(data):
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raise Exception("Array field has a constant size, and it doesn't match the actual value")
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elif two[0]:
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answer += self.calcPackSize(two[0], len(data))
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for each in data:
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answer += self.calcPackSize(two[1], each)
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return answer
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# "printf" string specifier
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if format[:1] == '%':
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# format string like specifier
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return len(format % data)
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# asciiz specifier
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if format[:1] == 'z':
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return len(data)+1
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# asciiz specifier
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if format[:1] == 'u':
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l = len(data)
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return l + (l & 1 and 3 or 2)
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# DCE-RPC/NDR string specifier
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if format[:1] == 'w':
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l = len(data)
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return 12+l+l % 2
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# literal specifier
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if format[:1] == ':':
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return len(data)
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# struct like specifier
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return calcsize(format)
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def calcUnpackSize(self, format, data, field = None):
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if self.debug:
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print(" calcUnpackSize( %s | %s | %r)" % (field, format, data))
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# void specifier
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if format[:1] == '_':
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return 0
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addressField = self.findAddressFieldFor(field)
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if addressField is not None:
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if not self[addressField]:
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return 0
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try:
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lengthField = self.findLengthFieldFor(field)
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return int(self[lengthField])
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except Exception:
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pass
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# XXX: Try to match to actual values, raise if no match
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# quote specifier
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if format[:1] == "'" or format[:1] == '"':
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return len(format)-1
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# address specifier
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two = format.split('&')
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if len(two) == 2:
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return self.calcUnpackSize(two[0], data)
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# code specifier
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two = format.split('=')
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if len(two) >= 2:
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return self.calcUnpackSize(two[0], data)
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# length specifier
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two = format.split('-')
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if len(two) == 2:
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return self.calcUnpackSize(two[0], data)
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# array specifier
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two = format.split('*')
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if len(two) == 2:
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answer = 0
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if two[0]:
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if two[0].isdigit():
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number = int(two[0])
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else:
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answer += self.calcUnpackSize(two[0], data)
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number = self.unpack(two[0], data[:answer])
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while number:
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number -= 1
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answer += self.calcUnpackSize(two[1], data[answer:])
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else:
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while answer < len(data):
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answer += self.calcUnpackSize(two[1], data[answer:])
|
|
return answer
|
|
|
|
# "printf" string specifier
|
|
if format[:1] == '%':
|
|
raise Exception("Can't guess the size of a printf like specifier for unpacking")
|
|
|
|
# asciiz specifier
|
|
if format[:1] == 'z':
|
|
return data.index(b('\x00'))+1
|
|
|
|
# asciiz specifier
|
|
if format[:1] == 'u':
|
|
l = data.index(b('\x00\x00'))
|
|
return l + (l & 1 and 3 or 2)
|
|
|
|
# DCE-RPC/NDR string specifier
|
|
if format[:1] == 'w':
|
|
l = unpack('<L', data[:4])[0]
|
|
return 12+l*2
|
|
|
|
# literal specifier
|
|
if format[:1] == ':':
|
|
return len(data)
|
|
|
|
# struct like specifier
|
|
return calcsize(format)
|
|
|
|
def calcPackFieldSize(self, fieldName, format = None):
|
|
if format is None:
|
|
format = self.formatForField(fieldName)
|
|
|
|
return self.calcPackSize(format, self[fieldName])
|
|
|
|
def formatForField(self, fieldName):
|
|
for field in self.commonHdr+self.structure:
|
|
if field[0] == fieldName:
|
|
return field[1]
|
|
raise Exception("Field %s not found" % fieldName)
|
|
|
|
def findAddressFieldFor(self, fieldName):
|
|
descriptor = '&%s' % fieldName
|
|
l = len(descriptor)
|
|
for field in self.commonHdr+self.structure:
|
|
if field[1][-l:] == descriptor:
|
|
return field[0]
|
|
return None
|
|
|
|
def findLengthFieldFor(self, fieldName):
|
|
descriptor = '-%s' % fieldName
|
|
l = len(descriptor)
|
|
for field in self.commonHdr+self.structure:
|
|
if field[1][-l:] == descriptor:
|
|
return field[0]
|
|
return None
|
|
|
|
def zeroValue(self, format):
|
|
two = format.split('*')
|
|
if len(two) == 2:
|
|
if two[0].isdigit():
|
|
return (self.zeroValue(two[1]),)*int(two[0])
|
|
|
|
if not format.find('*') == -1:
|
|
return ()
|
|
if 's' in format:
|
|
return b''
|
|
if format in ['z',':','u']:
|
|
return b''
|
|
if format == 'w':
|
|
return b('\x00\x00')
|
|
|
|
return 0
|
|
|
|
def clear(self):
|
|
for field in self.commonHdr + self.structure:
|
|
self[field[0]] = self.zeroValue(field[1])
|
|
|
|
def dump(self, msg = None, indent = 0):
|
|
if msg is None:
|
|
msg = self.__class__.__name__
|
|
ind = ' '*indent
|
|
print("\n%s" % msg)
|
|
fixedFields = []
|
|
for field in self.commonHdr+self.structure:
|
|
i = field[0]
|
|
if i in self.fields:
|
|
fixedFields.append(i)
|
|
if isinstance(self[i], Structure):
|
|
self[i].dump('%s%s:{' % (ind,i), indent = indent + 4)
|
|
print("%s}" % ind)
|
|
else:
|
|
print("%s%s: {%r}" % (ind,i,self[i]))
|
|
# Do we have remaining fields not defined in the structures? let's
|
|
# print them
|
|
remainingFields = list(set(self.fields) - set(fixedFields))
|
|
for i in remainingFields:
|
|
if isinstance(self[i], Structure):
|
|
self[i].dump('%s%s:{' % (ind,i), indent = indent + 4)
|
|
print("%s}" % ind)
|
|
else:
|
|
print("%s%s: {%r}" % (ind,i,self[i]))
|
|
|
|
def pretty_print(x):
|
|
if chr(x) in '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~ ':
|
|
return chr(x)
|
|
else:
|
|
return u'.'
|
|
|
|
def hexdump(data, indent = ''):
|
|
if data is None:
|
|
return
|
|
if isinstance(data, int):
|
|
data = str(data).encode('utf-8')
|
|
x=bytearray(data)
|
|
strLen = len(x)
|
|
i = 0
|
|
while i < strLen:
|
|
line = " %s%04x " % (indent, i)
|
|
for j in range(16):
|
|
if i+j < strLen:
|
|
line += "%02X " % x[i+j]
|
|
else:
|
|
line += u" "
|
|
if j%16 == 7:
|
|
line += " "
|
|
line += " "
|
|
line += ''.join(pretty_print(x) for x in x[i:i+16] )
|
|
print (line)
|
|
i += 16
|
|
|
|
def parse_bitmask(dict, value):
|
|
ret = ''
|
|
|
|
for i in range(0, 31):
|
|
flag = 1 << i
|
|
|
|
if value & flag == 0:
|
|
continue
|
|
|
|
if flag in dict:
|
|
ret += '%s | ' % dict[flag]
|
|
else:
|
|
ret += "0x%.8X | " % flag
|
|
|
|
if len(ret) == 0:
|
|
return '0'
|
|
else:
|
|
return ret[:-3]
|