plaso-rubanetra/plaso/engine/collector.py
2020-04-06 18:48:34 +02:00

422 lines
15 KiB
Python

#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# Copyright 2013 The Plaso Project Authors.
# Please see the AUTHORS file for details on individual authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Generic collector that supports both file system and image files."""
import hashlib
import logging
import os
from dfvfs.helpers import file_system_searcher
from dfvfs.lib import definitions as dfvfs_definitions
from dfvfs.lib import errors as dfvfs_errors
from dfvfs.path import factory as path_spec_factory
from dfvfs.resolver import resolver as path_spec_resolver
from plaso.engine import queue
from plaso.lib import errors
class Collector(queue.ItemQueueProducer):
"""Class that implements a collector object."""
def __init__(
self, process_queue, source_path, source_path_spec,
resolver_context=None):
"""Initializes the collector object.
The collector discovers all the files that need to be processed by
the workers. Once a file is discovered it is added to the process queue
as a path specification (instance of dfvfs.PathSpec).
Args:
process_queue: The process queue (instance of Queue). This queue contains
the file entries that need to be processed.
source_path: Path of the source file or directory.
source_path_spec: The source path specification (instance of
dfvfs.PathSpec) as determined by the file system
scanner. The default is None.
resolver_context: Optional resolver context (instance of dfvfs.Context).
The default is None.
"""
super(Collector, self).__init__(process_queue)
self._filter_find_specs = None
self._fs_collector = FileSystemCollector(process_queue)
self._resolver_context = resolver_context
# TODO: remove the need to pass source_path
self._source_path = os.path.abspath(source_path)
self._source_path_spec = source_path_spec
self._vss_stores = None
def __enter__(self):
"""Enters a with statement."""
return self
def __exit__(self, unused_type, unused_value, unused_traceback):
"""Exits a with statement."""
return
def _ProcessImage(self, volume_path_spec, find_specs=None):
"""Processes a volume within a storage media image.
Args:
volume_path_spec: The path specification of the volume containing
the file system.
find_specs: Optional list of find specifications (instances of
dfvfs.FindSpec). The default is None.
"""
if find_specs:
logging.debug(u'Collecting from image file: {0:s} with filter'.format(
self._source_path))
else:
logging.debug(u'Collecting from image file: {0:s}'.format(
self._source_path))
path_spec = path_spec_factory.Factory.NewPathSpec(
dfvfs_definitions.TYPE_INDICATOR_TSK, location=u'/',
parent=volume_path_spec)
try:
file_system = path_spec_resolver.Resolver.OpenFileSystem(
path_spec, resolver_context=self._resolver_context)
except IOError as exception:
logging.error(
u'Unable to open file system with error: {0:s}'.format(exception))
return
try:
self._fs_collector.Collect(
file_system, path_spec, find_specs=find_specs)
except (dfvfs_errors.AccessError, dfvfs_errors.BackEndError) as exception:
logging.warning(u'{0:s}'.format(exception))
if find_specs:
logging.debug(u'Collection from image with filter FAILED.')
else:
logging.debug(u'Collection from image FAILED.')
return
if self._abort:
return
if self._vss_stores:
self._ProcessVSS(volume_path_spec, find_specs=find_specs)
if find_specs:
logging.debug(u'Collection from image with filter COMPLETED.')
else:
logging.debug(u'Collection from image COMPLETED.')
def _ProcessVSS(self, volume_path_spec, find_specs=None):
"""Processes a VSS volume within a storage media image.
Args:
volume_path_spec: The path specification of the volume containing
the file system.
find_specs: Optional list of find specifications (instances of
dfvfs.FindSpec). The default is None.
"""
logging.info(u'Processing VSS.')
vss_path_spec = path_spec_factory.Factory.NewPathSpec(
dfvfs_definitions.TYPE_INDICATOR_VSHADOW, location=u'/',
parent=volume_path_spec)
vss_file_entry = path_spec_resolver.Resolver.OpenFileEntry(
vss_path_spec, resolver_context=self._resolver_context)
number_of_vss = vss_file_entry.number_of_sub_file_entries
# In plaso 1 represents the first store index in dfvfs and pyvshadow 0
# represents the first store index so 1 is subtracted.
vss_store_range = [store_nr - 1 for store_nr in self._vss_stores]
for store_index in vss_store_range:
if self._abort:
return
if find_specs:
logging.info((
u'Collecting from VSS volume: {0:d} out of: {1:d} '
u'with filter').format(store_index + 1, number_of_vss))
else:
logging.info(u'Collecting from VSS volume: {0:d} out of: {1:d}'.format(
store_index + 1, number_of_vss))
vss_path_spec = path_spec_factory.Factory.NewPathSpec(
dfvfs_definitions.TYPE_INDICATOR_VSHADOW, store_index=store_index,
parent=volume_path_spec)
path_spec = path_spec_factory.Factory.NewPathSpec(
dfvfs_definitions.TYPE_INDICATOR_TSK, location=u'/',
parent=vss_path_spec)
file_system = path_spec_resolver.Resolver.OpenFileSystem(
path_spec, resolver_context=self._resolver_context)
try:
self._fs_collector.Collect(
file_system, path_spec, find_specs=find_specs)
except (dfvfs_errors.AccessError, dfvfs_errors.BackEndError) as exception:
logging.warning(u'{0:s}'.format(exception))
if find_specs:
logging.debug(
u'Collection from VSS store: {0:d} with filter FAILED.'.format(
store_index + 1))
else:
logging.debug(u'Collection from VSS store: {0:d} FAILED.'.format(
store_index + 1))
return
if find_specs:
logging.debug(
u'Collection from VSS store: {0:d} with filter COMPLETED.'.format(
store_index + 1))
else:
logging.debug(u'Collection from VSS store: {0:d} COMPLETED.'.format(
store_index + 1))
def Collect(self):
"""Collects files from the source."""
source_file_entry = path_spec_resolver.Resolver.OpenFileEntry(
self._source_path_spec, resolver_context=self._resolver_context)
if not source_file_entry:
logging.warning(u'No files to collect.')
self.SignalEndOfInput()
return
if (not source_file_entry.IsDirectory() and
not source_file_entry.IsFile() and
not source_file_entry.IsDevice()):
raise errors.CollectorError(
u'Source path: {0:s} not a device, file or directory.'.format(
self._source_path))
type_indicator = self._source_path_spec.type_indicator
if type_indicator == dfvfs_definitions.TYPE_INDICATOR_OS:
if source_file_entry.IsFile():
self.ProduceItem(self._source_path_spec)
else:
file_system = path_spec_resolver.Resolver.OpenFileSystem(
self._source_path_spec, resolver_context=self._resolver_context)
try:
self._fs_collector.Collect(
file_system, self._source_path_spec,
find_specs=self._filter_find_specs)
except (dfvfs_errors.AccessError,
dfvfs_errors.BackEndError) as exception:
logging.warning(u'{0:s}'.format(exception))
else:
self._ProcessImage(
self._source_path_spec.parent, find_specs=self._filter_find_specs)
self.SignalEndOfInput()
def SetCollectDirectoryMetadata(self, collect_directory_metadata):
"""Sets the collect directory metadata flag.
Args:
collect_directory_metadata: Boolean value to indicate to collect
directory metadata.
"""
self._fs_collector.SetCollectDirectoryMetadata(collect_directory_metadata)
def SetFilter(self, filter_find_specs):
"""Sets the collection filter find specifications.
Args:
filter_find_specs: List of filter find specifications (instances of
dfvfs.FindSpec).
"""
self._filter_find_specs = filter_find_specs
def SetVssInformation(self, vss_stores):
"""Sets the Volume Shadow Snapshots (VSS) information.
This function will enable VSS collection.
Args:
vss_stores: The range of VSS stores to include in the collection,
where 1 represents the first store.
"""
self._vss_stores = vss_stores
def SignalAbort(self):
"""Signals the producer to abort."""
super(Collector, self).SignalAbort()
self._fs_collector.SignalAbort()
class FileSystemCollector(queue.ItemQueueProducer):
"""Class that implements a file system collector object."""
def __init__(self, process_queue):
"""Initializes the collector object.
The collector discovers all the files that need to be processed by
the workers. Once a file is discovered it is added to the process queue
as a path specification (instance of dfvfs.PathSpec).
Args:
process_queue: The process queue (instance of Queue). This queue contains
the file entries that need to be processed.
"""
super(FileSystemCollector, self).__init__(process_queue)
self._collect_directory_metadata = True
self._duplicate_file_check = False
self._hashlist = {}
self.number_of_file_entries = 0
def __enter__(self):
"""Enters a with statement."""
return self
def __exit__(self, unused_type, unused_value, unused_traceback):
"""Exits a with statement."""
return
def _CalculateNTFSTimeHash(self, file_entry):
"""Return a hash value calculated from a NTFS file's metadata.
Args:
file_entry: The file entry (instance of TSKFileEntry).
Returns:
A hash value (string) that can be used to determine if a file's timestamp
value has changed.
"""
stat_object = file_entry.GetStat()
ret_hash = hashlib.md5()
ret_hash.update('atime:{0:d}.{1:d}'.format(
getattr(stat_object, 'atime', 0),
getattr(stat_object, 'atime_nano', 0)))
ret_hash.update('crtime:{0:d}.{1:d}'.format(
getattr(stat_object, 'crtime', 0),
getattr(stat_object, 'crtime_nano', 0)))
ret_hash.update('mtime:{0:d}.{1:d}'.format(
getattr(stat_object, 'mtime', 0),
getattr(stat_object, 'mtime_nano', 0)))
ret_hash.update('ctime:{0:d}.{1:d}'.format(
getattr(stat_object, 'ctime', 0),
getattr(stat_object, 'ctime_nano', 0)))
return ret_hash.hexdigest()
def _ProcessDirectory(self, file_entry):
"""Processes a directory and extract its metadata if necessary."""
# Need to do a breadth-first search otherwise we'll hit the Python
# maximum recursion depth.
sub_directories = []
for sub_file_entry in file_entry.sub_file_entries:
if self._abort:
return
try:
if not sub_file_entry.IsAllocated() or sub_file_entry.IsLink():
continue
except dfvfs_errors.BackEndError as exception:
logging.warning(
u'Unable to process file: {0:s} with error: {1:s}'.format(
sub_file_entry.path_spec.comparable.replace(
u'\n', u';'), exception))
continue
# For TSK-based file entries only, ignore the virtual /$OrphanFiles
# directory.
if sub_file_entry.type_indicator == dfvfs_definitions.TYPE_INDICATOR_TSK:
if file_entry.IsRoot() and sub_file_entry.name == u'$OrphanFiles':
continue
if sub_file_entry.IsDirectory():
# This check is here to improve performance by not producing
# path specifications that don't get processed.
if self._collect_directory_metadata:
self.ProduceItem(sub_file_entry.path_spec)
self.number_of_file_entries += 1
sub_directories.append(sub_file_entry)
elif sub_file_entry.IsFile():
# If we are dealing with a VSS we want to calculate a hash
# value based on available timestamps and compare that to previously
# calculated hash values, and only include the file into the queue if
# the hash does not match.
if self._duplicate_file_check:
hash_value = self._CalculateNTFSTimeHash(sub_file_entry)
inode = getattr(sub_file_entry.path_spec, 'inode', 0)
if inode in self._hashlist:
if hash_value in self._hashlist[inode]:
continue
self._hashlist.setdefault(inode, []).append(hash_value)
self.ProduceItem(sub_file_entry.path_spec)
self.number_of_file_entries += 1
for sub_file_entry in sub_directories:
if self._abort:
return
try:
self._ProcessDirectory(sub_file_entry)
except (dfvfs_errors.AccessError, dfvfs_errors.BackEndError) as exception:
logging.warning(u'{0:s}'.format(exception))
def Collect(self, file_system, path_spec, find_specs=None):
"""Collects files from the file system.
Args:
file_system: The file system (instance of dfvfs.FileSystem).
path_spec: The path specification (instance of dfvfs.PathSpec).
find_specs: Optional list of find specifications (instances of
dfvfs.FindSpec). The default is None.
"""
if find_specs:
searcher = file_system_searcher.FileSystemSearcher(file_system, path_spec)
for path_spec in searcher.Find(find_specs=find_specs):
if self._abort:
return
self.ProduceItem(path_spec)
self.number_of_file_entries += 1
else:
file_entry = file_system.GetFileEntryByPathSpec(path_spec)
self._ProcessDirectory(file_entry)
def SetCollectDirectoryMetadata(self, collect_directory_metadata):
"""Sets the collect directory metadata flag.
Args:
collect_directory_metadata: Boolean value to indicate to collect
directory metadata.
"""
self._collect_directory_metadata = collect_directory_metadata