mirror of
https://github.com/volatilityfoundation/volatility3.git
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333 lines
14 KiB
Python
333 lines
14 KiB
Python
import collections
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import logging
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import math
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import struct
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import typing
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from volatility.framework import exceptions, interfaces
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from volatility.framework.configuration import requirements
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vollog = logging.getLogger(__name__)
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IteratorValue = typing.Tuple[typing.List[typing.Tuple[str, int, int]], int]
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class classproperty(object):
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"""Class property decorator
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Note this will change the return type """
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def __init__(self, func: typing.Callable[[typing.Any], typing.Any]) -> None:
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self._func = func
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def __get__(self, _owner_self, owner_cls: typing.Type) -> typing.Any:
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return self._func(owner_cls)
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class Intel(interfaces.layers.TranslationLayerInterface):
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"""Translation Layer for the Intel IA32 memory mapping"""
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priority = 40
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_entry_format = "<I"
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_page_size_in_bits = 12
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_bits_per_register = 32
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# NOTE: _maxphyaddr is MAXPHYADDR as defined in the Intel specs *NOT* the maximum physical address
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_maxphyaddr = 32
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_maxvirtaddr = _maxphyaddr
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_structure = [('page directory', 10, False),
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('page table', 10, True)]
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_direct_metadata = collections.ChainMap({'architecture': 'Intel32'},
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interfaces.layers.TranslationLayerInterface._direct_metadata)
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def __init__(self,
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context: interfaces.context.ContextInterface,
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config_path: str,
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name: str,
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metadata: typing.Optional[typing.Dict[str, typing.Any]] = None) -> None:
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super().__init__(context = context, config_path = config_path, name = name, metadata = metadata)
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self._base_layer = self._check_type(self.config["memory_layer"], str)
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self._swap_layers = [] # type: typing.List[str]
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self._check_type(self.config.get("swap_layers", False), bool)
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self._page_map_offset = self._check_type(self.config["page_map_offset"], int)
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self._optimize_scan = False
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# These can vary depending on the type of space
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self._index_shift = int(math.ceil(math.log2(struct.calcsize(self._entry_format))))
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@classproperty
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def page_size(cls) -> int:
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"""Page size for the intel address space.
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All Intel address spaces work on 4096 byte pages"""
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return 1 << cls._page_size_in_bits
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@classproperty
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def bits_per_register(cls) -> int:
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"""Returns the bits_per_register to determine the range of an IntelTranslationLayer"""
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return cls._bits_per_register
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@classproperty
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def minimum_address(cls) -> int: # type: ignore
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return 0
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@classproperty
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def maximum_address(cls) -> int: # type: ignore
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return (1 << cls._maxvirtaddr) - 1
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@classproperty
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def structure(cls) -> typing.List[typing.Tuple[str, int, bool]]:
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return cls._structure
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@staticmethod
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def _mask(value: int, high_bit: int, low_bit: int) -> int:
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"""Returns the bits of a value between highbit and lowbit inclusive"""
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high_mask = (2 ** (high_bit + 1)) - 1
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low_mask = (2 ** low_bit) - 1
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mask = (high_mask ^ low_mask)
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# print(high_bit, low_bit, bin(mask), bin(value))
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return value & mask
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@staticmethod
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def _page_is_valid(entry: int) -> bool:
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"""Returns whether a particular page is valid based on its entry"""
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return bool(entry & 1)
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def _translate(self, offset: int) -> typing.Tuple[int, int, str]:
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"""Translates a specific offset based on paging tables
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Returns the translated offset, the contiguous pagesize that the translated address lives in and the layer_name that the address lives in
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"""
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# Setup the entry and how far we are through the offset
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# Position maintains the number of bits left to process
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# We or with 0x1 to ensure our page_map_offset is always valid
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position = min(self._maxvirtaddr, self._bits_per_register) - 1
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entry = self._mask(self._page_map_offset, position, 0) | 0x1
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# Run through the offset in various chunks
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for (name, size, large_page) in self._structure:
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# Check we're valid
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if not self._page_is_valid(entry):
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raise exceptions.PagedInvalidAddressException(self.name, offset, position + 1, entry,
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"Page Fault at entry " + hex(entry) + " in table " + name)
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# Check if we're a large page
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if large_page and (entry & (1 << 7)):
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# We're a large page, the rest is finished below
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# If we want to implement PSE-36, it would need to be done here
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break
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# Figure out how much of the offset we should be using
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start = position
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position -= size
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index = self._mask(offset, start, position + 1) >> (position + 1)
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# Grab the base address of the table we'll be getting the next entry from
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base_address = self._mask(entry, self._maxphyaddr - 1, size + self._index_shift)
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# Create the offset for the next entry
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table_offset = base_address | (index << self._index_shift)
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# Read out the new entry from memory
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entry, = struct.unpack(self._entry_format, self._context.memory.read(self._base_layer, table_offset,
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struct.calcsize(self._entry_format)))
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# Now we're done
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if not self._page_is_valid(entry):
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raise exceptions.PagedInvalidAddressException(self.name, offset, position + 1, entry,
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"Page Fault at entry {} in page entry".format(hex(entry)))
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page = self._mask(entry, self._maxphyaddr - 1, position + 1) | self._mask(offset, position, 0)
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return page, 1 << (position + 1), self._base_layer
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def is_valid(self, offset: int, length: int = 1) -> bool:
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"""Returns whether the address offset can be translated to a valid address"""
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try:
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# TODO: Consider reimplementing this, since calls to mapping can call is_valid
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return all([self._context.memory[layer].is_valid(mapped_offset) for _, mapped_offset, _, layer in
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self.mapping(offset, length)])
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except exceptions.InvalidAddressException:
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return False
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def mapping(self,
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offset: int,
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length: int,
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ignore_errors: bool = False) -> typing.Iterable[typing.Tuple[int, int, int, str]]:
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"""Returns a sorted iterable of (offset, mapped_offset, length, layer) mappings
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This allows translation layers to provide maps of contiguous regions in one layer
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"""
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if length == 0:
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try:
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mapped_offset, _, layer_name = self._translate(offset)
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except exceptions.InvalidAddressException:
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if not ignore_errors:
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raise
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raise StopIteration
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yield (offset, mapped_offset, length, layer_name)
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raise StopIteration
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while length > 0:
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try:
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chunk_offset, page_size, layer_name = self._translate(offset)
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except exceptions.PagedInvalidAddressException as excp:
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if ignore_errors:
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mask = (1 << excp.invalid_bits) - 1
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length_diff = (mask + 1 - (offset & mask))
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length -= length_diff
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offset += length_diff
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else:
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raise
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else:
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chunk_size = min(page_size - (chunk_offset % page_size), length)
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yield (offset, chunk_offset, chunk_size, layer_name)
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length -= chunk_size
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offset += chunk_size
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@property
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def dependencies(self) -> typing.List[str]:
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"""Returns a list of the lower layer names that this layer is dependent upon"""
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# TODO: Add in the whole buffalo
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return [self._base_layer] + self._swap_layers
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@classmethod
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def get_requirements(cls) -> typing.List[interfaces.configuration.RequirementInterface]:
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return [requirements.TranslationLayerRequirement(name = 'memory_layer',
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optional = False),
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requirements.LayerListRequirement(name = 'swap_layers',
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optional = True),
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requirements.IntRequirement(name = 'page_map_offset',
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optional = False),
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requirements.IntRequirement(name = 'kernel_virtual_offset',
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optional = True),
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requirements.StringRequirement(name = 'linux_banner',
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optional = True)]
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def _scan_iterator(self,
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scanner: interfaces.layers.ScannerInterface,
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min_address: int,
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max_address: int) \
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-> typing.Iterable[IteratorValue]:
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for mapped in self.mapping(min_address, max_address - min_address, ignore_errors = True):
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offset, mapped_offset, length, layer_name = mapped
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while length > 0:
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chunk_size = min(length, scanner.chunk_size + scanner.overlap)
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yield [(layer_name, mapped_offset, chunk_size)], offset + chunk_size
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# It we've got more than the scanner's chunk_size, only move up by the chunk_size
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if chunk_size > scanner.chunk_size:
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chunk_size -= scanner.overlap
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length -= chunk_size
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mapped_offset += chunk_size
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offset += chunk_size
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# We ignore the type due to the iterator_value, actually it only needs to match the output from _scan_iterator
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def _scan_chunk(self,
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scanner: interfaces.layers.ScannerInterface,
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min_address: int,
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max_address: int,
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progress: interfaces.layers.ProgressValue,
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iterator_value: IteratorValue) -> typing.List[typing.Any]:
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data_to_scan, chunk_end = iterator_value
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data = b''
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for layer_name, address, chunk_size in data_to_scan:
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try:
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data += self.context.memory[layer_name].read(address, chunk_size)
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except exceptions.InvalidAddressException:
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vollog.debug(
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"Invalid address in layer {} found scanning {} at address {:x}".format(layer_name, self.name,
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address))
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progress.value = chunk_end
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return list(scanner(data, chunk_end - len(data)))
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def _scan_metric(self,
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_scanner: interfaces.layers.ScannerInterface,
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min_address: int,
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max_address: int,
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value: int) -> float:
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return max(0, ((value - min_address) * 100) / (max_address - min_address))
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class IntelPAE(Intel):
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"""Class for handling Physical Address Extensions for Intel architectures"""
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priority = 35
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_entry_format = "<Q"
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_bits_per_register = 32
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_maxphyaddr = 40
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_maxvirtaddr = 32
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_structure = [('page directory pointer', 2, False),
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('page directory', 9, True),
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('page table', 9, True)]
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class Intel32e(Intel):
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"""Class for handling 64-bit (32-bit extensions) for Intel architectures"""
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priority = 30
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_direct_metadata = collections.ChainMap({'architecture': 'Intel64'}, Intel._direct_metadata)
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_entry_format = "<Q"
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_bits_per_register = 64
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_maxphyaddr = 52
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_maxvirtaddr = 48
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_structure = [('page map layer 4', 9, False),
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('page directory pointer', 9, True),
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('page directory', 9, True),
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('page table', 9, True)]
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class WindowsMixin(Intel):
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@staticmethod
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def _page_is_valid(entry: int) -> bool:
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"""Returns whether a particular page is valid based on its entry
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Windows uses additional "available" bits to store flags
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These flags allow windows to determine whether a page is still valid
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Bit 11 is the transition flag, and Bit 10 is the prototype flag
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For more information, see Windows Internals (6th Ed, Part 2, pages 268-269)
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"""
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return bool((entry & 1) or ((entry & 1 << 11) and not entry & 1 << 10))
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def _translate_swap(self, layer: Intel, offset: int, bit_offset: int):
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try:
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return super()._translate(offset)
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except exceptions.PagedInvalidAddressException as excp:
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entry = excp.entry
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tbit = bool(entry & (1 << 11))
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pbit = bool(entry & (1 << 10))
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unknown_bit = bool(entry & (1 << 7))
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n = (entry >> 1) & 0xF
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vbit = bool(entry & 1)
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if (not tbit and not pbit and not vbit and unknown_bit) and (
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(entry >> bit_offset) != 0):
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swap_offset = entry >> bit_offset << excp.invalid_bits
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if layer.config.get('swap_layers', False):
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swap_layer_name = layer.config.get(interfaces.configuration.path_join('swap_layers',
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'swap_layers' + str(n)),
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None)
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if swap_layer_name:
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return swap_offset, 1 << excp.invalid_bits, swap_layer_name
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raise exceptions.SwappedInvalidAddressException(layer_name = excp.layer_name,
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invalid_address = excp.invalid_address,
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invalid_bits = excp.invalid_bits,
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entry = excp.entry,
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swap_offset = swap_offset)
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raise
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### These must be full separate classes so that JSON configs re-create them properly
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class WindowsIntel(WindowsMixin, Intel):
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def _translate(self, offset):
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return self._translate_swap(self, offset, self._page_size_in_bits)
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class WindowsIntelPAE(WindowsMixin, IntelPAE):
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def _translate(self, offset):
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return self._translate_swap(self, offset, self._bits_per_register)
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class WindowsIntel32e(WindowsMixin, Intel32e):
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def _translate(self, offset):
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return self._translate_swap(self, offset, self._bits_per_register // 2)
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