volatility3/volatility3/framework/plugins/linux/malware/hidden_modules.py

# This file is Copyright 2024 Volatility Foundation and licensed under the Volatility Software License 1.0
# which is available at https://www.volatilityfoundation.org/license/vsl-v1.0
#
import logging
from typing import List, Set, Tuple, Iterable
from volatility3.framework.symbols.linux.utilities import (
    modules as linux_utilities_modules,
)
from volatility3.framework import interfaces, exceptions, deprecation
from volatility3.framework.configuration import requirements
from volatility3.framework.symbols.linux import extensions
from volatility3.framework.interfaces import plugins

vollog = logging.getLogger(__name__)


class Hidden_modules(plugins.PluginInterface):
    """Carves memory to find hidden kernel modules"""

    _required_framework_version = (2, 25, 0)
    _version = (3, 0, 2)

    @classmethod
    def find_hidden_modules(
        cls, context, vmlinux_module_name: str
    ) -> extensions.module:
        if context.symbol_space.verify_table_versions(
            "dwarf2json", lambda version, _: (not version) or version < (0, 8, 0)
        ):
            raise exceptions.SymbolSpaceError(
                "Invalid symbol table, please ensure the ISF table produced by dwarf2json was created with version 0.8.0 or later"
            )

        known_module_addresses = cls.get_lsmod_module_addresses(
            context, vmlinux_module_name
        )
        modules_memory_boundaries = (
            linux_utilities_modules.Modules.get_modules_memory_boundaries(
                context, vmlinux_module_name
            )
        )

        yield from linux_utilities_modules.Modules.get_hidden_modules(
            context,
            vmlinux_module_name,
            known_module_addresses,
            modules_memory_boundaries,
        )

    @classmethod
    def get_hidden_modules(
        cls,
        context: interfaces.context.ContextInterface,
        vmlinux_module_name: str,
        known_module_addresses: Set[int],
        modules_memory_boundaries: Tuple,
    ) -> Iterable[interfaces.objects.ObjectInterface]:
        """Enumerate hidden modules by taking advantage of memory address alignment patterns

        This technique is much faster and uses less memory than the traditional scan method
        in Volatility2, but it doesn't work with older kernels.

        From kernels 4.2 struct module allocation are aligned to the L1 cache line size.
        In i386/amd64/arm64 this is typically 64 bytes. However, this can be changed in
        the Linux kernel configuration via CONFIG_X86_L1_CACHE_SHIFT. The alignment can
        also be obtained from the DWARF info i.e. DW_AT_alignment<64>, but dwarf2json
        doesn't support this feature yet.
        In kernels < 4.2, alignment attributes are absent in the struct module, meaning
        alignment cannot be guaranteed. Therefore, for older kernels, it's better to use
        the traditional scan technique.

        Args:
            context: The context to retrieve required elements (layers, symbol tables) from
            vmlinux_module_name: The name of the kernel module on which to operate
            known_module_addresses: Set with known module addresses
            modules_memory_boundaries: Minimum and maximum address boundaries for module allocation.
        Yields:
            module objects
        """
        return linux_utilities_modules.get_hidden_modules(
            vmlinux_module_name, known_module_addresses, modules_memory_boundaries
        )

    run = linux_utilities_modules.ModuleDisplayPlugin.run
    _generator = linux_utilities_modules.ModuleDisplayPlugin.generator
    implementation = find_hidden_modules

    @classmethod
    def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]:
        return [
            requirements.VersionRequirement(
                name="linux_utilities_modules_module_display_plugin",
                component=linux_utilities_modules.ModuleDisplayPlugin,
                version=(1, 0, 0),
            ),
            requirements.VersionRequirement(
                name="linux_utilities_modules",
                component=linux_utilities_modules.Modules,
                version=(3, 0, 1),
            ),
        ] + linux_utilities_modules.ModuleDisplayPlugin.get_requirements()

    @staticmethod
    @deprecation.deprecated_method(
        replacement=linux_utilities_modules.Modules.get_modules_memory_boundaries,
        removal_date="2025-09-25",
        replacement_version=(3, 0, 0),
    )
    def get_modules_memory_boundaries(
        context: interfaces.context.ContextInterface,
        vmlinux_module_name: str,
    ) -> Tuple[int, int]:
        return linux_utilities_modules.Modules.get_modules_memory_boundaries(
            context, vmlinux_module_name
        )

    @deprecation.deprecated_method(
        replacement=linux_utilities_modules.Modules.get_module_address_alignment,
        removal_date="2025-09-25",
        replacement_version=(3, 0, 0),
    )
    @classmethod
    def _get_module_address_alignment(
        cls,
        context: interfaces.context.ContextInterface,
        vmlinux_module_name: str,
    ) -> int:
        """Obtain the module memory address alignment.

        struct module is aligned to the L1 cache line, which is typically 64 bytes for most
        common i386/AMD64/ARM64 configurations. In some cases, it can be 128 bytes, but this
        will still work.

        Args:
            context: The context to retrieve required elements (layers, symbol tables) from
            vmlinux_module_name: The name of the kernel module on which to operate

        Returns:
            The struct module alignment
        """
        return linux_utilities_modules.get_module_address_alignment(
            context, vmlinux_module_name
        )

    @deprecation.deprecated_method(
        replacement=linux_utilities_modules.Modules.get_hidden_modules,
        removal_date="2025-09-25",
        replacement_version=(3, 0, 0),
    )
    @staticmethod
    @deprecation.deprecated_method(
        replacement=linux_utilities_modules.Modules.validate_alignment_patterns,
        removal_date="2025-09-25",
        replacement_version=(3, 0, 0),
    )
    def _validate_alignment_patterns(
        addresses: Iterable[int],
        address_alignment: int,
    ) -> bool:
        """Check if the memory addresses meet our alignments patterns

        Args:
            addresses: Iterable with the address values
            address_alignment: Number of bytes for alignment validation

        Returns:
            True if all the addresses meet the alignment
        """
        return linux_utilities_modules.validate_alignment_patterns(
            addresses, address_alignment
        )

    @classmethod
    def get_lsmod_module_addresses(
        cls,
        context: interfaces.context.ContextInterface,
        vmlinux_module_name: str,
    ) -> Set[int]:
        """Obtain a set the known module addresses from linux.lsmod plugin

        Args:
            context: The context to retrieve required elements (layers, symbol tables) from
            vmlinux_module_name: The name of the kernel module on which to operate

        Returns:
            A set containing known kernel module addresses
        """
        vmlinux = context.modules[vmlinux_module_name]
        vmlinux_layer = context.layers[vmlinux.layer_name]

        known_module_addresses = {
            vmlinux_layer.canonicalize(module.vol.offset)
            for module in linux_utilities_modules.Modules.list_modules(
                context, vmlinux_module_name
            )
        }
        return known_module_addresses