Source code for plaso.engine.yaml_filter_file

# -*- coding: utf-8 -*-
"""YAML-based filter file."""

from __future__ import unicode_literals

import io
import yaml

from plaso.engine import path_filters
from plaso.lib import errors


[docs]class YAMLFilterFile(object): """YAML-based filter file. A YAML-based filter file contains one or more path filters. description: Include filter with Linux paths. type: include path_separator: '/' paths: - '/usr/bin' Where: * description, is an optional description of the purpose of the path filter; * type, defines the filter type, which can be "include" or "exclude"; * path_separator, defines the path segment separator, which is "/" by default; * paths, defines regular expression of paths to filter on. Note that the regular expression need to be defined per path segment, for example to filter "/usr/bin/echo" and "/usr/sbin/echo" the following expression could be defined "/usr/(bin|sbin)/echo". Note that when the path segment separator is defined as "\\" it needs to be escaped as "\\\\", since "\\" is used by the regular expression as escape character. A path may contain path expansion attributes, for example: %{SystemRoot}\\\\System32 """ _SUPPORTED_KEYS = frozenset([ 'description', 'path_separator', 'paths', 'type']) def _ReadFilterDefinition(self, filter_definition_values): """Reads a filter definition from a dictionary. Args: filter_definition_values (dict[str, object]): filter definition values. Returns: PathFilter: a path filter. Raises: ParseError: if the format of the filter definition is not set or incorrect. """ if not filter_definition_values: raise errors.ParseError('Missing filter definition values.') different_keys = set(filter_definition_values) - self._SUPPORTED_KEYS if different_keys: different_keys = ', '.join(different_keys) raise errors.ParseError('Undefined keys: {0:s}'.format(different_keys)) filter_type = filter_definition_values.get('type', None) if not filter_type: raise errors.ParseError('Invalid path filter definition missing type.') if filter_type not in ( path_filters.PathFilter.FILTER_TYPE_EXCLUDE, path_filters.PathFilter.FILTER_TYPE_INCLUDE): raise errors.ParseError( 'Invalid path filter definition unsupported type: {0!s}.'.format( filter_type)) paths = filter_definition_values.get('paths', None) if not paths: raise errors.ParseError('Invalid path filter definition missing paths.') description = filter_definition_values.get('description', None) path_separator = filter_definition_values.get('path_separator', '/') return path_filters.PathFilter( filter_type, description=description, path_separator=path_separator, paths=paths) def _ReadFromFileObject(self, file_object): """Reads the path filters from a file-like object. Args: file_object (file): filter file-like object. Yields: PathFilter: path filter. """ yaml_generator = yaml.safe_load_all(file_object) for yaml_definition in yaml_generator: yield self._ReadFilterDefinition(yaml_definition)
[docs] def ReadFromFile(self, path): """Reads the path filters from the YAML-based filter file. Args: path (str): path to a filter file. Returns: list[PathFilter]: path filters. """ with io.open(path, 'r', encoding='utf-8') as file_object: return list(self._ReadFromFileObject(file_object))