diff --git a/volatility3/framework/plugins/vmscan.py b/volatility3/framework/plugins/vmscan.py new file mode 100644 index 000000000..64377d7d8 --- /dev/null +++ b/volatility3/framework/plugins/vmscan.py @@ -0,0 +1,217 @@ +# This file is Copyright 2023 Volatility Foundation and licensed under the Volatility Software License 1.0 +# which is available at https://www.volatilityfoundation.org/license/vsl-v1.0 +# + +import enum +import logging +import os +import struct +from typing import Dict, List + +from volatility3.framework import constants, exceptions, interfaces, renderers +from volatility3.framework.configuration import requirements +from volatility3.framework.interfaces import configuration, plugins +from volatility3.framework.renderers import format_hints +from volatility3.framework.symbols import intermed + +vollog = logging.getLogger(__name__) + + +class VMCSTest(enum.IntFlag): + VMCS_ABORT_INVALID = enum.auto() + VMCS_LINK_PTR_IS_NOT_FS = enum.auto() + VMCS_HOST_CR4_NO_VTX = enum.auto() + VMCS_CR3_IS_ZERO = enum.auto() + VMCS_GUEST_CR4_RESERVED = enum.auto() + + +class PageStartScanner(interfaces.layers.ScannerInterface): + def __init__(self, signatures: List[bytes], page_size: int = 0x1000): + super().__init__() + if not len(signatures): + raise ValueError("No signatures passed to constructor") + self._siglen = len(signatures[0]) + for item in signatures: + if len(item) != self._siglen: + raise ValueError( + "Signatures of different lengths passed to PageStartScanner" + ) + self._signatures = signatures + self._page_size = page_size + + def __call__(self, data: bytes, data_offset: int): + """Scans only the start of every page, to see whether a signature is present or not""" + for page_start in range( + data_offset % self._page_size, len(data), self._page_size + ): + if data[page_start : page_start + self._siglen] in self._signatures: + yield ( + page_start + data_offset, + data[page_start : page_start + self._siglen], + ) + + +class Vmscan(plugins.PluginInterface): + """Scans for Intel VT-d structues and generates VM volatility configs for them""" + + _required_framework_version = (2, 2, 0) + _version = (1, 0, 0) + + STRICTLY_REQUIRED_TESTS = { + VMCSTest.VMCS_ABORT_INVALID, + VMCSTest.VMCS_LINK_PTR_IS_NOT_FS, + VMCSTest.VMCS_HOST_CR4_NO_VTX, + } + + @classmethod + def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]: + return [ + requirements.TranslationLayerRequirement( + name="primary", description="Physical base memory layer" + ), + requirements.IntRequirement( + name="log-threshold", + description="Number of criteria failed to log to debug output", + default=2, + optional=True, + ), + ] + + # Scan for VMCS structures based on the known VMCS structures + # found in symbols/vmcs directory + + def _gather_vmcs_structures( + self, context: interfaces.context.ContextInterface, config_path: str + ) -> Dict[bytes, str]: + """Enumerate all JSON files containing VMCS information and return the structures + Signatures can be generated using data extracted using the vmcs_layout tool at + https://github.com/google/rekall/tree/master/tools/linux/vmcs_layout + + Args: + context: The volatility context to work against + config_path: The location to store symbol table configurations under + + Returns: + A dictionary of pattern bytes to the string representation of the architecture + """ + filenames = intermed.IntermediateSymbolTable.file_symbol_url( + os.path.join("generic", "vmcs") + ) + table_names = [] + for filename in filenames: + base_name = os.path.basename(filename).split(".")[0] + table_name = intermed.IntermediateSymbolTable.create( + context, + configuration.path_join(config_path, "vmcs"), + os.path.join("generic", "vmcs"), + filename=base_name, + ) + table_names.append(table_name) + + result = {} + for table_name in table_names: + symbol_table = context.symbol_space[table_name] + revision_id = struct.pack( + " List[str]: + """Runs tests to verify whether a block of data is a VMCS page + Some tests based on the Hypervisor Memory Forensics paper by + Mariano Graziano, Andrea Lanzi and Davide Balzarotti + + Args: + context: The volatility context to be used for this call + vmcs: The instantiated VMCS object to verify + + Returns: + The list of failed criteria that the VMCS did not meet + """ + + # The VMCS should have been constructed on the physical layer (even a nested VMCS) + physical_layer_name = vmcs.vol.layer_name + + failed_tests: VMCSTest = VMCSTest(0) + # The abort field must be valid (generally 0, although other abort codes may exist) + if context.layers[physical_layer_name].read(vmcs.vol.offset + 4, 4) not in [ + b"\x00\x00\x00\x00" + ]: + failed_tests |= VMCSTest.VMCS_ABORT_INVALID + # The vmcs link pointer is supposed to always be set + if vmcs.vmcs_link_ptr != 0xFFFFFFFFFFFFFFFF: + failed_tests |= VMCSTest.VMCS_LINK_PTR_IS_NOT_FS + # To have a VMCS the host needs the VTx bit set in CR4, this can false positive often when all bits are set + if (vmcs.host_cr4 & 1 << 13) == 0: + failed_tests |= VMCSTest.VMCS_HOST_CR4_NO_VTX + # The guest CR3 is *exceptionally* unlikely to be 0 and the guest cr4 is likely to have some bits unset + if (vmcs.guest_cr3 == 0) or (vmcs.host_cr3 == 0): + failed_tests |= VMCSTest.VMCS_CR3_IS_ZERO + # CR4 registers have certain bits reserved that should not be set + if vmcs.guest_cr4 & 0xFFFFFFFFFF889000: + failed_tests |= VMCSTest.VMCS_GUEST_CR4_RESERVED + + if failed_tests and failed_tests.name: + failed_list = failed_tests.name.split("|") + return failed_list + + return [] + + def _generator(self): + # Gather VMCS structures + structures = self._gather_vmcs_structures(self.context, self.config_path) + # Scan memory for them + layer = self.context.layers[self.config["primary"]] + + # Try to move down to the highest physical layer + if layer.config.get("memory_layer"): + layer = self.context.layers[layer.config["memory_layer"]] + + # Run the scan + for offset, match in layer.scan( + self.context, + PageStartScanner(list(structures.keys())), + self._progress_callback, + ): + try: + vmcs = self.context.object( + structures[match] + constants.BANG + "_VMCS", + layer.name, + offset=offset, + ) + failed_list = self._verify_vmcs_page(self.context, vmcs) + if not failed_list: + yield ( + 0, + ( + structures[match], + format_hints.Hex(vmcs.vol.offset), + format_hints.Hex(vmcs.ept), + format_hints.Hex(vmcs.guest_cr3), + ), + ) + if len(failed_list) <= self.config["log-threshold"]: + vollog.debug( + f"Potential {structures[match]} VMCS found at {vmcs.vol.offset:x} with failed criteria: {failed_list}" + ) + except (exceptions.InvalidAddressException, AttributeError): + # Not what we're looking for + continue + + def run(self): + return renderers.TreeGrid( + [ + ("Architecture", str), + ("VMCS Physical offset", format_hints.Hex), + ("EPT", format_hints.Hex), + ("Guest CR3", format_hints.Hex), + ], + self._generator(), + ) diff --git a/volatility3/symbols/generic/vmcs/haswell-architecture.json b/volatility3/symbols/generic/vmcs/haswell-architecture.json new file mode 100644 index 000000000..33b2e55d8 --- /dev/null +++ b/volatility3/symbols/generic/vmcs/haswell-architecture.json @@ -0,0 +1,131 @@ +{ + "base_types": { + "pointer": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 8 + }, + "unsigned char": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 1 + }, + "unsigned long": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 4 + }, + "unsigned long long": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 8 + }, + "unsigned short": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 2 + } + }, + "enums": {}, + "metadata": { + "format": "6.1.0", + "producer": { + "datetime": "2021-07-31T17:37:28.313255", + "name": "vmextract-by-hand", + "version": "0.0.1" + } + }, + "symbols": { + "revision_id": { + "address": 0, + "constant_data": "MTg=" + } + }, + "user_types": { + "_VMCS": { + "fields": { + "ept": { + "offset": 320, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "executive_vmcs_ptr": { + "offset": 208, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "guest_cr3": { + "offset": 528, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "guest_cr4": { + "offset": 536, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "guest_pdpte": { + "offset": 544, + "type": { + "count": 4, + "kind": "array", + "subtype": { + "kind": "struct", + "name": "unsigned long long" + } + } + }, + "guest_physical_addr": { + "offset": 328, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "host_cr3": { + "offset": 816, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "host_cr4": { + "offset": 824, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "vmcs_link_ptr": { + "offset": 248, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "vpid": { + "offset": 206, + "type": { + "kind": "struct", + "name": "unsigned short" + } + } + }, + "kind": "struct", + "size": 4096 + } + } +} \ No newline at end of file diff --git a/volatility3/symbols/generic/vmcs/skylake-architecture.json b/volatility3/symbols/generic/vmcs/skylake-architecture.json new file mode 100644 index 000000000..78b110d94 --- /dev/null +++ b/volatility3/symbols/generic/vmcs/skylake-architecture.json @@ -0,0 +1,131 @@ +{ + "base_types": { + "pointer": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 8 + }, + "unsigned char": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 1 + }, + "unsigned long": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 4 + }, + "unsigned long long": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 8 + }, + "unsigned short": { + "endian": "little", + "kind": "int", + "signed": false, + "size": 2 + } + }, + "enums": {}, + "metadata": { + "format": "6.1.0", + "producer": { + "datetime": "2021-07-16T16:21:01.062423", + "name": "vmextract-by-hand", + "version": "0.0.1" + } + }, + "symbols": { + "revision_id": { + "address": 0, + "constant_data": "NA==" + } + }, + "user_types": { + "_VMCS": { + "fields": { + "ept": { + "offset": 320, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "executive_vmcs_ptr": { + "offset": 208, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "guest_cr3": { + "offset": 528, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "guest_cr4": { + "offset": 536, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "guest_pdpte": { + "offset": 544, + "type": { + "count": 4, + "kind": "array", + "subtype": { + "kind": "struct", + "name": "unsigned long long" + } + } + }, + "guest_physical_addr": { + "offset": 328, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "host_cr3": { + "offset": 816, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "host_cr4": { + "offset": 824, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "vmcs_link_ptr": { + "offset": 248, + "type": { + "kind": "struct", + "name": "unsigned long long" + } + }, + "vpid": { + "offset": 206, + "type": { + "kind": "struct", + "name": "unsigned short" + } + } + }, + "kind": "struct", + "size": 4096 + } + } +}