diff --git a/volatility3/framework/automagic/__init__.py b/volatility3/framework/automagic/__init__.py index 626126c8c..e4d422c99 100644 --- a/volatility3/framework/automagic/__init__.py +++ b/volatility3/framework/automagic/__init__.py @@ -22,7 +22,7 @@ from volatility3.framework.configuration import requirements vollog = logging.getLogger(__name__) windows_automagic = [ - 'ConstructionMagic', 'LayerStacker', 'WintelHelper', 'KernelPDBScanner', 'WinSwapLayers', 'KernelModule' + 'ConstructionMagic', 'LayerStacker', 'KernelPDBScanner', 'WinSwapLayers', 'KernelModule' ] linux_automagic = ['ConstructionMagic', 'LayerStacker', 'LinuxBannerCache', 'LinuxSymbolFinder', 'KernelModule'] @@ -46,7 +46,7 @@ def available(context: interfaces.context.ContextInterface) -> List[interfaces.a clazz(context, interfaces.configuration.path_join(config_path, clazz.__name__)) for clazz in class_subclasses(interfaces.automagic.AutomagicInterface) ], - key = lambda x: x.priority) + key = lambda x: x.priority) def choose_automagic( diff --git a/volatility3/framework/automagic/windows.py b/volatility3/framework/automagic/windows.py index 147602fac..eb63a75e5 100644 --- a/volatility3/framework/automagic/windows.py +++ b/volatility3/framework/automagic/windows.py @@ -28,7 +28,7 @@ The self-referential indices for older versions of windows are listed below: """ import logging import struct -from typing import Any, Generator, List, Optional, Tuple, Type +from typing import Generator, List, Optional, Tuple, Type, Iterable from volatility3.framework import interfaces, layers, constants from volatility3.framework.configuration import requirements @@ -37,162 +37,43 @@ from volatility3.framework.layers import intel vollog = logging.getLogger(__name__) -class DtbTest: - """This class generically contains the tests for a page based on a set of - class parameters. - - When constructed it contains all the information necessary to - extract a specific index from a page and determine whether it points - back to that page's offset. - """ - - def __init__(self, layer_type: Type[layers.intel.Intel], ptr_struct: str, ptr_reference: List[int], - mask: int) -> None: - self.layer_type = layer_type - self.ptr_struct = ptr_struct - self.ptr_size = struct.calcsize(ptr_struct) - self.ptr_reference = ptr_reference - self.mask = mask - self.page_size: int = layer_type.page_size - - def _unpack(self, value: bytes) -> int: - return struct.unpack("<" + self.ptr_struct, value)[0] - - def __call__(self, data: bytes, data_offset: int, page_offset: int) -> Optional[Tuple[int, Any]]: - """Tests a specific page in a chunk of data to see if it contains a - self-referential pointer. - - Args: - data: The chunk of data that contains the page to be scanned - data_offset: Where, within the layer, the chunk of data lives - page_offset: Where, within the data, the page to be scanned starts - - Returns: - A valid DTB within this page (and an additional parameter for data) - """ - for ptr_reference in self.ptr_reference: - value = data[page_offset + (ptr_reference * self.ptr_size):page_offset + - ((ptr_reference + 1) * self.ptr_size)] - try: - ptr = self._unpack(value) - except struct.error: - return None - # The value *must* be present (bit 0) since it's a mapped page - # It's almost always writable (bit 1) - # It's occasionally Super, but not reliably so, haven't checked when/why not - # The top 3-bits are usually ignore (which in practice means 0 - # Need to find out why the middle 3-bits are usually 6 (0110) - if ptr != 0 and (ptr & self.mask == data_offset + page_offset) & (ptr & 0xFF1 == 0x61): - dtb = (ptr & self.mask) - return self.second_pass(dtb, data, data_offset) - return None - - def second_pass(self, dtb: int, data: bytes, data_offset: int) -> Optional[Tuple[int, Any]]: - """Re-reads over the whole page to validate other records based on the - number of pages marked user vs super. - - Args: - dtb: The identified dtb that needs validating - data: The chunk of data that contains the dtb to be validated - data_offset: Where, within the layer, the chunk of data lives - - Returns: - A valid DTB within this page - """ - page = data[dtb - data_offset:dtb - data_offset + self.page_size] - usr_count, sup_count = 0, 0 - for i in range(0, self.page_size, self.ptr_size): - val = self._unpack(page[i:i + self.ptr_size]) - if val & 0x1: - sup_count += 0 if (val & 0x4) else 1 - usr_count += 1 if (val & 0x4) else 0 - # print(hex(dtb), usr_count, sup_count, usr_count + sup_count) - # We sometimes find bogus DTBs at 0x16000 with a very low sup_count and 0 usr_count - # I have a winxpsp2-x64 image with identical usr/sup counts at 0x16000 and 0x24c00 as well as the actual 0x3c3000 - if usr_count or sup_count > 5: - return dtb, None - return None - - -class DtbTest32bit(DtbTest): - - def __init__(self) -> None: - super().__init__(layer_type = layers.intel.WindowsIntel, - ptr_struct = "I", - ptr_reference = [0x300], - mask = 0xFFFFF000) - - -class DtbTest64bit(DtbTest): - - def __init__(self) -> None: - super().__init__(layer_type = layers.intel.WindowsIntel32e, - ptr_struct = "Q", - ptr_reference = range(0x1E0, 0x1FF), - mask = 0x3FFFFFFFFFF000) - - # As of Windows-10 RS1+, the ptr_reference is randomized: - # https://blahcat.github.io/2020/06/15/playing_with_self_reference_pml4_entry/ - # So far, we've only seen examples between 0x1e0 and 0x1ff - - -class DtbTestPae(DtbTest): - - def __init__(self) -> None: - super().__init__(layer_type = layers.intel.WindowsIntelPAE, - ptr_struct = "Q", - ptr_reference = [0x3], - mask = 0x3FFFFFFFFFF000) - - def second_pass(self, dtb: int, data: bytes, data_offset: int) -> Optional[Tuple[int, Any]]: - """PAE top level directory tables contains four entries and the self- - referential pointer occurs in the second level of tables (so as not to - use up a full quarter of the space). This is very high in the space, - and occurs in the fourht (last quarter) second-level table. The - second-level tables appear always to come sequentially directly after - the real dtb. The value for the real DTB is therefore four page - earlier (and the fourth entry should point back to the `dtb` parameter - this function was originally passed. - - Args: - dtb: The identified self-referential pointer that needs validating - data: The chunk of data that contains the dtb to be validated - data_offset: Where, within the layer, the chunk of data lives - - Returns: - Returns the actual DTB of the PAE space - """ - dtb -= 0x4000 - # If we're not in something that the overlap would pick up - if dtb - data_offset >= 0: - pointers = data[dtb - data_offset + (3 * self.ptr_size):dtb - data_offset + (4 * self.ptr_size)] - val = self._unpack(pointers) - if (val & self.mask == dtb + 0x4000) and (val & 0xFFF == 0x001): - return dtb, None - return None - - -class DtbSelfReferential(DtbTest): +class DtbSelfReferential: """A generic DTB test which looks for a self-referential pointer at *any* index within the page.""" - def __init__(self, layer_type: Type[layers.intel.Intel], ptr_struct: str, ptr_reference: int, mask: int) -> None: - super().__init__(layer_type = layer_type, ptr_struct = ptr_struct, ptr_reference = ptr_reference, mask = mask) + def __init__(self, layer_type: Type[layers.intel.Intel], ptr_struct: str, mask: int, + valid_range: Iterable[int], reserved_bits: int) -> None: + self.layer_type = layer_type + self.ptr_struct = ptr_struct + self.ptr_size = struct.calcsize(ptr_struct) + self.mask = mask + self.page_size: int = layer_type.page_size + self.valid_range = valid_range + self.reserved_bits = reserved_bits def __call__(self, data: bytes, data_offset: int, page_offset: int) -> Optional[Tuple[int, int]]: page = data[page_offset:page_offset + self.page_size] if not page: return None ref_pages = set() + for ref in range(0, self.page_size, self.ptr_size): ptr_data = page[ref:ref + self.ptr_size] - if len(ptr_data) == self.ptr_size: - ptr, = struct.unpack(self.ptr_struct, ptr_data) - if ((ptr & self.mask) == (data_offset + page_offset)) and (data_offset + page_offset > 0): + ptr, = struct.unpack(self.ptr_struct, ptr_data) + # For both Intel-32e, bit 7 is reserved (more are reserved in PAE), so if that's ever set, + # we can move on + if (ptr & self.reserved_bits) and (ptr & 0x01): + return None + if ((ptr & self.mask) == (data_offset + page_offset)) and (data_offset + page_offset > 0): + # Pointer must be valid + if (ptr & 0x01): ref_pages.add(ref) + # The DTB is extremely unlikely to refer back to itself. so the number of reference should always be exactly 1 if len(ref_pages) == 1: - return (data_offset + page_offset), ref_pages.pop() + ref_page = ref_pages.pop() + if (ref_page // self.ptr_size) in self.valid_range: + return (data_offset + page_offset), ref_page return None @@ -201,8 +82,9 @@ class DtbSelfRef32bit(DtbSelfReferential): def __init__(self): super().__init__(layer_type = layers.intel.WindowsIntel, ptr_struct = "I", - ptr_reference = 0x300, - mask = 0xFFFFF000) + mask = 0xFFFFF000, + valid_range = [0x300], + reserved_bits = 0x0) class DtbSelfRef64bit(DtbSelfReferential): @@ -210,8 +92,35 @@ class DtbSelfRef64bit(DtbSelfReferential): def __init__(self) -> None: super().__init__(layer_type = layers.intel.WindowsIntel32e, ptr_struct = "Q", - ptr_reference = 0x1ED, - mask = 0x3FFFFFFFFFF000) + mask = 0x3FFFFFFFFFF000, + valid_range = range(0x100, 0x1ff), + reserved_bits = 0x80) + + +class DtbSelfRef64bitOldWindows(DtbSelfReferential): + + def __init__(self) -> None: + super().__init__(layer_type = layers.intel.WindowsIntel32e, + ptr_struct = "Q", + mask = 0x3FFFFFFFFFF000, + valid_range = [0x1ed], + reserved_bits = 0x80) + + +class DtbSelfRefPae(DtbSelfReferential): + + def __init__(self) -> None: + super().__init__(layer_type = layers.intel.WindowsIntelPAE, + ptr_struct = "Q", + valid_range = [0x3], + mask = 0x3FFFFFFFFFF000, + reserved_bits = 0x0) + + def __call__(self, *args, **kwargs): + dtb = super().__call__(*args, **kwargs) + if dtb: + return dtb[0] - 0x4000, dtb[1] + return dtb class PageMapScanner(interfaces.layers.ScannerInterface): @@ -219,82 +128,33 @@ class PageMapScanner(interfaces.layers.ScannerInterface): architecture.""" overlap = 0x4000 thread_safe = True - tests = [DtbTest64bit(), DtbTest32bit(), DtbTestPae()] + tests = [DtbSelfRef64bit(), DtbSelfRefPae(), DtbSelfRef32bit()] """The default tests to run when searching for DTBs""" - def __init__(self, tests: List[DtbTest]) -> None: + def __init__(self, tests: Optional[List[DtbSelfReferential]]) -> None: super().__init__() - self.tests = tests + if tests: + self.tests = tests - def __call__(self, data: bytes, data_offset: int) -> Generator[Tuple[DtbTest, int], None, None]: - for test in self.tests: - for page_offset in range(0, len(data), 0x1000): + def __call__(self, data: bytes, data_offset: int) -> Generator[Tuple[DtbSelfReferential, int], None, None]: + for page_offset in range(0, len(data), 0x1000): + for test in self.tests: result = test(data, data_offset, page_offset) if result is not None: yield (test, result[0]) -class WintelHelper(interfaces.automagic.AutomagicInterface): - """Windows DTB finder based on self-referential pointers. - - This class adheres to the :class:`~volatility3.framework.interfaces.automagic.AutomagicInterface` interface - and both determines the directory table base of an intel layer if one hasn't been specified, and constructs - the intel layer if necessary (for example when reconstructing a pre-existing configuration). - - It will scan for existing TranslationLayers that do not have a DTB using the :class:`PageMapScanner` - """ - priority = 20 - tests = [DtbTest64bit(), DtbTest32bit(), DtbTestPae()] - - def __call__(self, - context: interfaces.context.ContextInterface, - config_path: str, - requirement: interfaces.configuration.RequirementInterface, - progress_callback: constants.ProgressCallback = None) -> None: - useful = [] - sub_config_path = interfaces.configuration.path_join(config_path, requirement.name) - if (isinstance(requirement, requirements.TranslationLayerRequirement) - and requirement.requirements.get("class", False) and requirement.unsatisfied(context, config_path)): - class_req = requirement.requirements["class"] - - for test in self.tests: - if (test.layer_type.__module__ + "." + test.layer_type.__name__ == class_req.config_value( - context, sub_config_path)): - useful.append(test) - - # Determine if a class has been chosen - # Once an appropriate class has been chosen, attempt to determine the page_map_offset value - if ("memory_layer" in requirement.requirements - and not requirement.requirements["memory_layer"].unsatisfied(context, sub_config_path)): - # Only bother getting the DTB if we don't already have one - page_map_offset_path = interfaces.configuration.path_join(sub_config_path, "page_map_offset") - if not context.config.get(page_map_offset_path, None): - physical_layer_name = requirement.requirements["memory_layer"].config_value( - context, sub_config_path) - if not isinstance(physical_layer_name, str): - raise TypeError(f"Physical layer name is not a string: {sub_config_path}") - physical_layer = context.layers[physical_layer_name] - # Check lower layer metadata first - if physical_layer.metadata.get('page_map_offset', None): - context.config[page_map_offset_path] = physical_layer.metadata['page_map_offset'] - else: - hits = physical_layer.scan(context, PageMapScanner(useful), progress_callback) - for test, dtb in hits: - context.config[page_map_offset_path] = dtb - break - else: - return None - if isinstance(requirement, interfaces.configuration.ConstructableRequirementInterface): - requirement.construct(context, config_path) - else: - for subreq in requirement.requirements.values(): - self(context, sub_config_path, subreq) - - class WindowsIntelStacker(interfaces.automagic.StackerLayerInterface): stack_order = 40 exclusion_list = ['mac', 'linux'] + # Group these by region so we only run over the data once + test_sets = [("Detecting Self-referential pointer for recent windows", + [DtbSelfRef64bit()], [(0x150000, 0x150000), (0x650000, 0xa0000)]), + ("Older windows fixed location self-referential pointers", + [DtbSelfRefPae(), DtbSelfRef32bit(), DtbSelfRef64bitOldWindows()], [(0x30000, 0x1000000)]) + ] + @classmethod def stack(cls, context: interfaces.context.ContextInterface, @@ -338,44 +198,36 @@ class WindowsIntelStacker(interfaces.automagic.StackerLayerInterface): config_path, "page_map_offset")] = base_layer.metadata['page_map_offset'] layer = layer_type(context, config_path = config_path, name = new_layer_name, metadata = {'os': 'Windows'}) - # Check for the self-referential pointer - if layer is None: - hits = base_layer.scan(context, PageMapScanner(WintelHelper.tests), progress_callback = progress_callback) - layer = None - config_path = None - for test, dtb in hits: + # Self Referential finder + for description, tests, sections in cls.test_sets: + vollog.debug(description) + # There is a very high chance that the DTB will live in these very narrow segments, assuming we couldn't find them previously + hits = context.layers[layer_name].scan(context, + PageMapScanner(tests = tests), + sections = sections, + progress_callback = progress_callback) + + # Flatten the generator + def sort_by_tests(x): + return tests.index(x[0]), x[1] + + hits = sorted(list(hits), key = sort_by_tests) + + if hits: + # TODO: Decide which to use if there are multiple options + test, page_map_offset = hits[0] + vollog.debug(f"{test.__class__.__name__} test succeeded at {hex(page_map_offset)}") new_layer_name = context.layers.free_layer_name("IntelLayer") config_path = interfaces.configuration.path_join("IntelHelper", new_layer_name) context.config[interfaces.configuration.path_join(config_path, "memory_layer")] = layer_name - context.config[interfaces.configuration.path_join(config_path, "page_map_offset")] = dtb + context.config[interfaces.configuration.path_join(config_path, "page_map_offset")] = page_map_offset + # TODO: Need to determine the layer type (chances are high it's x64, hence this default) layer = test.layer_type(context, config_path = config_path, name = new_layer_name, metadata = {'os': 'Windows'}) break - # Fall back to a heuristic for finding the Windows DTB - if layer is None: - vollog.debug("Self-referential pointer not in well-known location, moving to recent windows heuristic") - # There is a very high chance that the DTB will live in this narrow segment, assuming we couldn't find it previously - hits = context.layers[layer_name].scan(context, - PageMapScanner([DtbSelfRef64bit()]), - sections = [(0x1a0000, 0x50000)], - progress_callback = progress_callback) - # Flatten the generator - hits = list(hits) - if hits: - # TODO: Decide which to use if there are multiple options - test, page_map_offset = hits[0] - new_layer_name = context.layers.free_layer_name("IntelLayer") - config_path = interfaces.configuration.path_join("IntelHelper", new_layer_name) - context.config[interfaces.configuration.path_join(config_path, "memory_layer")] = layer_name - context.config[interfaces.configuration.path_join(config_path, "page_map_offset")] = page_map_offset - # TODO: Need to determine the layer type (chances are high it's x64, hence this default) - layer = layers.intel.WindowsIntel32e(context, - config_path = config_path, - name = new_layer_name, - metadata = {'os': 'Windows'}) if layer is not None and config_path: vollog.debug("DTB was found at: 0x{:0x}".format(context.config[interfaces.configuration.path_join( config_path, "page_map_offset")]))