Worked on script to extract data streams #1 (#98)

dfimagetools/artifact_filters.py

@@ -13,26 +13,35 @@
 class ArtifactDefinitionFiltersGenerator(object):
   """Generator of filters based on artifact definitions."""
 
-  def __init__(self, artifacts_registry, environment_variables, user_accounts):
+  # TODO: passing environment_variables and user_accounts via __init__ is
+  # deprecated.
+
+  def __init__(
+      self, artifacts_registry, environment_variables=None, user_accounts=None):
     """Initializes an artifact definition filters generator.
 
     Args:
       artifacts_registry (artifacts.ArtifactDefinitionsRegistry): artifact
           definitions registry.
-      environment_variables (list[EnvironmentVariable]): environment variables.
-      user_accounts (list[UserAccount]): user accounts.
+      environment_variables (Optional[list[EnvironmentVariable]]): environment
+          variables.
+      user_accounts (Optional[list[UserAccount]]]): user accounts.
     """
     super(ArtifactDefinitionFiltersGenerator, self).__init__()
     self._artifacts_registry = artifacts_registry
     self._environment_variables = environment_variables
     self._path_resolver = path_resolver.PathResolver()
     self._user_accounts = user_accounts
 
-  def _BuildFindSpecsFromArtifactDefinition(self, name):
+  def _BuildFindSpecsFromArtifactDefinition(
+      self, name, environment_variables=None, user_accounts=None):
     """Builds find specifications from an artifact definition.
 
     Args:
       name (str): name of the artifact definition.
+      environment_variables (Optional[list[EnvironmentVariable]]): environment
+          variables.
+      user_accounts (Optional[list[UserAccount]]): user accounts.
 
     Yields:
       dfvfs.FindSpec: file system (dfVFS) find specification.
@@ -61,7 +70,8 @@ def _BuildFindSpecsFromArtifactDefinition(self, name):
         if source_type == artifacts_definitions.TYPE_INDICATOR_ARTIFACT_GROUP:
           for source_name in set(source.names):
             for find_spec in self._BuildFindSpecsFromArtifactDefinition(
-                source_name):
+                source_name, environment_variables=environment_variables,
+                user_accounts=user_accounts):
               yield find_spec
 
         elif source_type in (
@@ -70,15 +80,22 @@ def _BuildFindSpecsFromArtifactDefinition(self, name):
             artifacts_definitions.TYPE_INDICATOR_PATH):
           for source_path in set(source.paths):
             for find_spec in self._BuildFindSpecsFromFileSourcePath(
-                source_path, source.separator):
+                source_path, source.separator,
+                environment_variables=environment_variables,
+                user_accounts=user_accounts):
               yield find_spec
 
-  def _BuildFindSpecsFromFileSourcePath(self, source_path, path_separator):
+  def _BuildFindSpecsFromFileSourcePath(
+      self, source_path, path_separator, environment_variables=None,
+      user_accounts=None):
     """Builds find specifications from a file source type.
 
     Args:
       source_path (str): file system path defined by the source.
       path_separator (str): file system path segment separator.
+      environment_variables (Optional[list[EnvironmentVariable]]): environment
+          variables.
+      user_accounts (Optional[list[UserAccount]]): user accounts.
 
     Yields:
       dfvfs.FindSpec: file system (dfVFS) find specification.
@@ -87,11 +104,11 @@ def _BuildFindSpecsFromFileSourcePath(self, source_path, path_separator):
         source_path, path_separator):
 
       for path in self._path_resolver.ExpandUsersVariable(
-          path_glob, path_separator, self._user_accounts):
+          path_glob, path_separator, user_accounts):
 
         if '%' in path:
           path = self._path_resolver.ExpandEnvironmentVariables(
-              path, path_separator, self._environment_variables)
+              path, path_separator, environment_variables)
 
         if not path.startswith(path_separator):
           continue
@@ -108,15 +125,27 @@ def _BuildFindSpecsFromFileSourcePath(self, source_path, path_separator):
 
         yield find_spec
 
-  def GetFindSpecs(self, names):
+  def GetFindSpecs(
+      self, names=None, environment_variables=None, user_accounts=None):
     """Retrieves find specifications for one or more artifact definitions.
 
     Args:
-      names (list[str]): names of the artifact definitions to filter on.
+      names (Optional[list[str]]): names of the artifact definitions to filter
+          on.
+      environment_variables (Optional[list[EnvironmentVariable]]): environment
+          variables.
+      user_accounts (Optional[list[UserAccount]]): user accounts.
 
     Yields:
       dfvfs.FindSpec: file system (dfVFS) find specification.
     """
-    for name in set(names):
-      for find_spec in self._BuildFindSpecsFromArtifactDefinition(name):
+    if self._environment_variables:
+      environment_variables = self._environment_variables
+    if self._user_accounts:
+      user_accounts = self._user_accounts
+
+    for name in set(names or []):
+      for find_spec in self._BuildFindSpecsFromArtifactDefinition(
+          name, environment_variables=environment_variables,
+          user_accounts=user_accounts):
         yield find_spec

dfimagetools/path_filters.py

@@ -0,0 +1,55 @@
+# -*- coding: utf-8 -*-
+"""Helper for filtering based on a path."""
+
+import re
+
+from dfvfs.helpers import file_system_searcher as dfvfs_file_system_searcher
+
+
+class PathFiltersGenerator(object):
+  """Generator of filters based on a path."""
+
+  _PARTITION_REGEX = re.compile(r'^p[1-9][0-9]*$')
+
+  def __init__(self, path):
+    """Initializes a path filters generator.
+
+    Args:
+      path (str): path.
+
+    Raises:
+      ValueError: if the path is missing.
+    """
+    # TODO: add option to not look for partition and volume in path
+    # TODO: determine file system path segment separator.
+
+    super(PathFiltersGenerator, self).__init__()
+    self._partition = None
+    self._path_segments = path.split('/')
+
+    if self._path_segments and not self._path_segments[0]:
+      self._path_segments.pop(0)
+
+    if self._path_segments and self._PARTITION_REGEX.match(
+        self._path_segments[0]):
+      self._partition = self._path_segments.pop(0)
+
+    if not self._path_segments:
+      raise ValueError('Missing path')
+
+  @property
+  def partition(self):
+    """Retrieves the partition.
+
+    Returns:
+      str: partition defined by the path filter or None if not available.
+    """
+    return self._partition
+
+  def GetFindSpecs(self):
+    """Retrieves find specifications.
+
+    Yields:
+      dfvfs.FindSpec: file system (dfVFS) find specification.
+    """
+    yield dfvfs_file_system_searcher.FindSpec(location=self._path_segments)

dfimagetools/scripts/extract_data_streams.py

@@ -15,6 +15,7 @@
 from dfimagetools import artifact_filters
 from dfimagetools import data_stream_writer
 from dfimagetools import file_entry_lister
+from dfimagetools import path_filters
 from dfimagetools import windows_registry
 from dfimagetools.helpers import command_line
 
@@ -47,7 +48,18 @@ def Main():
           'Path to a directory or file containing custom artifact definition '
           '.yaml files. '))
 
+  argument_parser.add_argument(
+      '--path', dest='path_filter', type=str, default=None, metavar='PATH',
+      action='store', help='Path of data stream to extract.')
+
   # TODO: add output group
+  argument_parser.add_argument(
+      '--no_aliases', '--no-aliases', dest='use_aliases', action='store_false',
+      default=True, help=(
+          'Disable the use of partition and/or volume aliases such as '
+          '/apfs{f449e580-e355-4e74-8880-05e46e4e3b1e} and use indices '
+          'such as /apfs1 instead.'))
+
   argument_parser.add_argument(
       '-t', '--target', dest='target', action='store', metavar='PATH',
       default=None, help=(
@@ -78,9 +90,8 @@ def Main():
       print('')
       return 1
 
-  # TODO: improve this, for now this script needs at least 1 filter.
-  if not options.artifact_filters:
-    print('[ERROR] no artifact filters were specified.')
+  elif not options.path_filter:
+    print('[ERROR] no extraction filters were specified.')
     print('')
     return 1
 
@@ -120,7 +131,21 @@ def Main():
       elif os.path.isfile(options.custom_artifact_definitions):
         registry.ReadFromFile(reader, options.custom_artifact_definitions)
 
-  entry_lister = file_entry_lister.FileEntryLister(mediator=mediator)
+    filter_generator = artifact_filters.ArtifactDefinitionFiltersGenerator(
+        registry)
+
+  elif options.path_filter:
+    filter_generator = path_filters.PathFiltersGenerator(options.path_filter)
+
+    if filter_generator.partition and options.partitions:
+      print(('[WARNING] partition specified in path filter will override '
+             '--partitions command line argument.'))
+      print('')
+
+      volume_scanner_options.partitions = [filter_generator.partition]
+
+  entry_lister = file_entry_lister.FileEntryLister(
+      mediator=mediator, use_aliases=options.use_aliases)
   find_specs_generated = False
 
   try:
@@ -132,24 +157,31 @@ def Main():
       return 1
 
     for base_path_spec in base_path_specs:
-      if not options.artifact_filters:
-        find_specs = []
-      else:
+      find_specs = []
+
+      if options.artifact_filters:
+        environment_variables = []
+        user_accounts = []
+
         windows_directory = entry_lister.GetWindowsDirectory(base_path_spec)
-        if not windows_directory:
-          environment_variables = []
-        else:
+        if windows_directory:
           winregistry_collector = windows_registry.WindowsRegistryCollector(
               base_path_spec, windows_directory)
 
           environment_variables = (
               winregistry_collector.CollectSystemEnvironmentVariables())
 
-        filter_generator = artifact_filters.ArtifactDefinitionFiltersGenerator(
-            registry, environment_variables, [])
+        # TODO: determine user accounts.
 
         names = options.artifact_filters.split(',')
-        find_specs = list(filter_generator.GetFindSpecs(names))
+        find_specs = list(filter_generator.GetFindSpecs(
+            names=names, environment_variables=environment_variables,
+            user_accounts=user_accounts))
+
+      elif options.path_filter:
+        find_specs = list(filter_generator.GetFindSpecs())
+
+      if filter_generator:
         if not find_specs:
           continue
 
@@ -184,8 +216,8 @@ def Main():
     return 1
 
   if options.artifact_filters and not find_specs_generated:
-    print('[ERROR] an artifact filter was specified but no corresponding '
-          'file system find specifications were generated.')
+    print('[ERROR] an extraction filter was specified but no corresponding '
+          'find specifications were generated.')
     print('')
     return 1