# -*- coding: utf-8 -*-
"""Windows EventLog resources database reader."""
import collections
import os
import sqlite3
from plaso.containers import artifacts
from plaso.engine import path_helper
from plaso.helpers.windows import languages
from plaso.helpers.windows import resource_files
from plaso.output import logger
[docs]class Sqlite3DatabaseFile(object):
"""Class that defines a sqlite3 database file."""
_HAS_TABLE_QUERY = (
'SELECT name FROM sqlite_master '
'WHERE type = "table" AND name = "{0:s}"')
def __init__(self):
"""Initializes the database file object."""
super(Sqlite3DatabaseFile, self).__init__()
self._connection = None
self._cursor = None
self.filename = None
self.read_only = None
[docs] def Close(self):
"""Closes the database file.
Raises:
RuntimeError: if the database is not opened.
"""
if not self._connection:
raise RuntimeError('Cannot close database not opened.')
# We need to run commit or not all data is stored in the database.
self._connection.commit()
self._connection.close()
self._connection = None
self._cursor = None
self.filename = None
self.read_only = None
[docs] def HasTable(self, table_name):
"""Determines if a specific table exists.
Args:
table_name (str): table name.
Returns:
bool: True if the table exists.
Raises:
RuntimeError: if the database is not opened.
"""
if not self._connection:
raise RuntimeError(
'Cannot determine if table exists database not opened.')
sql_query = self._HAS_TABLE_QUERY.format(table_name)
self._cursor.execute(sql_query)
if self._cursor.fetchone():
return True
return False
[docs] def GetValues(self, table_names, column_names, condition):
"""Retrieves values from a table.
Args:
table_names (list[str]): table names.
column_names (list[str]): column names.
condition (str): query condition such as
"log_source == 'Application Error'".
Yields:
sqlite3.row: row.
Raises:
RuntimeError: if the database is not opened.
"""
if not self._connection:
raise RuntimeError('Cannot retrieve values database not opened.')
if condition:
condition = ' WHERE {0:s}'.format(condition)
sql_query = 'SELECT {1:s} FROM {0:s}{2:s}'.format(
', '.join(table_names), ', '.join(column_names), condition)
self._cursor.execute(sql_query)
# TODO: have a look at https://docs.python.org/2/library/
# sqlite3.html#sqlite3.Row.
for row in self._cursor:
yield {
column_name: row[column_index]
for column_index, column_name in enumerate(column_names)}
[docs] def Open(self, filename, read_only=False):
"""Opens the database file.
Args:
filename (str): filename of the database.
read_only (Optional[bool]): True if the database should be opened in
read-only mode. Since sqlite3 does not support a real read-only
mode we fake it by only permitting SELECT queries.
Returns:
bool: True if successful.
Raises:
RuntimeError: if the database is already opened.
"""
if self._connection:
raise RuntimeError('Cannot open database already opened.')
self.filename = filename
self.read_only = read_only
try:
self._connection = sqlite3.connect(filename)
except sqlite3.OperationalError:
return False
if not self._connection:
return False
self._cursor = self._connection.cursor()
if not self._cursor:
return False
return True
[docs]class WinevtResourcesSqlite3DatabaseReader(object):
"""Windows EventLog resources SQLite database reader."""
def __init__(self):
"""Initializes a Windows EventLog resources SQLite database reader."""
super(WinevtResourcesSqlite3DatabaseReader, self).__init__()
self._database_file = Sqlite3DatabaseFile()
self._resouce_file_helper = resource_files.WindowsResourceFileHelper
self._string_format = 'wrc'
def _GetEventLogProviderKey(self, log_source):
"""Retrieves the EventLog provider key.
Args:
log_source (str): EventLog source.
Returns:
str: EventLog provider key or None if not available.
Raises:
RuntimeError: if more than one value is found in the database.
"""
table_names = ['event_log_providers']
column_names = ['event_log_provider_key']
condition = 'log_source == "{0:s}"'.format(log_source)
values_list = list(self._database_file.GetValues(
table_names, column_names, condition))
number_of_values = len(values_list)
if number_of_values == 0:
return None
if number_of_values == 1:
values = values_list[0]
return values['event_log_provider_key']
raise RuntimeError('More than one value found in database.')
def _GetMessage(self, message_file_key, lcid, message_identifier):
"""Retrieves a specific message from a specific message table.
Args:
message_file_key (int): message file key.
lcid (int): language code identifier (LCID).
message_identifier (int): message identifier.
Returns:
str: message string or None if not available.
Raises:
RuntimeError: if more than one value is found in the database.
"""
table_name = 'message_table_{0:d}_0x{1:08x}'.format(message_file_key, lcid)
has_table = self._database_file.HasTable(table_name)
if not has_table:
return None
column_names = ['message_string']
condition = 'message_identifier == "0x{0:08x}"'.format(message_identifier)
values = list(self._database_file.GetValues(
[table_name], column_names, condition))
number_of_values = len(values)
if number_of_values == 0:
return None
if number_of_values == 1:
return values[0]['message_string']
raise RuntimeError('More than one value found in database.')
def _GetMessageFileKeys(self, event_log_provider_key):
"""Retrieves the message file keys.
Args:
event_log_provider_key (int): EventLog provider key.
Yields:
int: message file key.
"""
table_names = ['message_file_per_event_log_provider']
column_names = ['message_file_key']
condition = 'event_log_provider_key == {0:d}'.format(
event_log_provider_key)
generator = self._database_file.GetValues(
table_names, column_names, condition)
for values in generator:
yield values['message_file_key']
[docs] def Close(self):
"""Closes the database reader object."""
self._database_file.Close()
[docs] def GetMessage(self, log_source, lcid, message_identifier):
"""Retrieves a specific message for a specific EventLog source.
Args:
log_source (str): EventLog source.
lcid (int): language code identifier (LCID).
message_identifier (int): message identifier.
Returns:
str: message string or None if not available.
"""
event_log_provider_key = self._GetEventLogProviderKey(log_source)
if not event_log_provider_key:
return None
generator = self._GetMessageFileKeys(event_log_provider_key)
if not generator:
return None
message_string = None
for message_file_key in generator:
message_string = self._GetMessage(
message_file_key, lcid, message_identifier)
if message_string:
break
if self._string_format == 'wrc':
message_string = self._resouce_file_helper.FormatMessageStringInPEP3101(
message_string)
return message_string
[docs] def Open(self, filename):
"""Opens the database reader object.
Args:
filename (str): filename of the database.
Returns:
bool: True if successful.
Raises:
RuntimeError: if the version or string format of the database
is not supported.
"""
if not self._database_file.Open(filename, read_only=True):
return False
version = self.GetMetadataAttribute('version')
if not version or version != '20150315':
raise RuntimeError('Unsupported version: {0:s}'.format(version))
string_format = self.GetMetadataAttribute('string_format')
if not string_format:
string_format = 'wrc'
if string_format not in ('pep3101', 'wrc'):
raise RuntimeError('Unsupported string format: {0:s}'.format(
string_format))
self._string_format = string_format
return True
[docs]class WinevtResourcesHelper(object):
"""Windows EventLog resources helper."""
# LCID 0x0409 is en-US.
DEFAULT_LCID = 0x0409
# The maximum number of cached message strings
_MAXIMUM_CACHED_MESSAGE_STRINGS = 32 * 1024
_WINEVT_RC_DATABASE = 'winevt-rc.db'
def __init__(
self, storage_reader, data_location, lcid, environment_variables):
"""Initializes Windows EventLog resources helper.
Args:
storage_reader (StorageReader): storage reader.
data_location (str): data location of the winevt-rc database.
lcid (int): Windows Language Code Identifier (LCID).
environment_variables (list[EnvironmentVariableArtifact]): environment
variable artifacts.
"""
language_tag = languages.WindowsLanguageHelper.GetLanguageTagForLCID(
lcid or self.DEFAULT_LCID)
super(WinevtResourcesHelper, self).__init__()
self._data_location = data_location
self._environment_variables = environment_variables or None
self._language_tag = language_tag.lower()
self._lcid = lcid or self.DEFAULT_LCID
self._message_string_cache = collections.OrderedDict()
self._storage_reader = storage_reader
self._windows_eventlog_message_files = None
self._windows_eventlog_providers = None
self._winevt_database_reader = None
def _CacheMessageString(
self, provider_identifier, log_source, message_identifier,
event_version, message_string):
"""Caches a specific message string.
Args:
provider_identifier (str): EventLog provider identifier.
log_source (str): EventLog source, such as "Application Error".
message_identifier (int): message identifier.
event_version (int): event version or None if not set.
message_string (str): message string.
"""
if len(self._message_string_cache) >= self._MAXIMUM_CACHED_MESSAGE_STRINGS:
self._message_string_cache.popitem(last=True)
if provider_identifier:
lookup_key = '{0:s}:0x{1:08x}'.format(
provider_identifier, message_identifier)
if event_version is not None:
lookup_key = '{0:s}:{1:d}'.format(lookup_key, event_version)
self._message_string_cache[lookup_key] = message_string
self._message_string_cache.move_to_end(lookup_key, last=False)
if log_source:
lookup_key = '{0:s}:0x{1:08x}'.format(log_source, message_identifier)
if event_version is not None:
lookup_key = '{0:s}:{1:d}'.format(lookup_key, event_version)
self._message_string_cache[lookup_key] = message_string
self._message_string_cache.move_to_end(lookup_key, last=False)
def _GetCachedMessageString(
self, provider_identifier, log_source, message_identifier, event_version):
"""Retrieves a specific cached message string.
Args:
provider_identifier (str): EventLog provider identifier.
log_source (str): EventLog source, such as "Application Error".
message_identifier (int): message identifier.
event_version (int): event version or None if not set.
Returns:
str: message string or None if not available.
"""
message_string = None
if provider_identifier:
lookup_key = '{0:s}:0x{1:08x}'.format(
provider_identifier, message_identifier)
if event_version is not None:
lookup_key = '{0:s}:{1:d}'.format(lookup_key, event_version)
message_string = self._message_string_cache.get(lookup_key, None)
if not message_string and log_source:
lookup_key = '{0:s}:0x{1:08x}'.format(log_source, message_identifier)
if event_version is not None:
lookup_key = '{0:s}:{1:d}'.format(lookup_key, event_version)
message_string = self._message_string_cache.get(lookup_key, None)
if message_string:
self._message_string_cache.move_to_end(lookup_key, last=False)
return message_string
def _GetWinevtRcDatabaseReader(self):
"""Opens the Windows EventLog resource database reader.
Returns:
WinevtResourcesSqlite3DatabaseReader: Windows EventLog resource
database reader or None.
"""
if not self._winevt_database_reader and self._data_location:
logger.warning((
'Falling back to {0:s}. Please make sure the Windows EventLog '
'message strings in the database correspond to those in the '
'EventLog files.').format(self._WINEVT_RC_DATABASE))
database_path = os.path.join(
self._data_location, self._WINEVT_RC_DATABASE)
if not os.path.isfile(database_path):
return None
self._winevt_database_reader = WinevtResourcesSqlite3DatabaseReader()
if not self._winevt_database_reader.Open(database_path):
self._winevt_database_reader = None
return self._winevt_database_reader
def _GetWinevtRcDatabaseMessageString(self, log_source, message_identifier):
"""Retrieves a specific Windows EventLog resource database message string.
Args:
log_source (str): EventLog source, such as "Application Error".
message_identifier (int): message identifier.
Returns:
str: message string or None if not available.
"""
database_reader = self._GetWinevtRcDatabaseReader()
if not database_reader:
return None
if self._lcid != self.DEFAULT_LCID:
message_string = database_reader.GetMessage(
log_source, self._lcid, message_identifier)
if message_string:
return message_string
return database_reader.GetMessage(
log_source, self.DEFAULT_LCID, message_identifier)
def _ReadEnvironmentVariables(self, storage_reader):
"""Reads the environment variables.
Args:
storage_reader (StorageReader): storage reader.
"""
# TODO: read environment variables from storage reader.
_ = storage_reader
self._environment_variables = [artifacts.EnvironmentVariableArtifact(
case_sensitive=False, name='SystemRoot', value='C:\\Windows')]
def _ReadWindowsEventLogMessageFiles(self, storage_reader):
"""Reads the Windows EventLog message files.
Args:
storage_reader (StorageReader): storage reader.
"""
self._windows_eventlog_message_files = {}
if storage_reader.HasAttributeContainers('windows_eventlog_message_file'):
for message_file in storage_reader.GetAttributeContainers(
'windows_eventlog_message_file'):
path, filename = path_helper.PathHelper.GetWindowsSystemPath(
message_file.path, self._environment_variables)
lookup_path = '\\'.join([path, filename]).lower()
message_file_identifier = message_file.GetIdentifier()
self._windows_eventlog_message_files[lookup_path] = (
message_file_identifier)
def _ReadWindowsEventLogMessageString(
self, storage_reader, provider_identifier, log_source,
message_identifier, event_version):
"""Reads an Windows EventLog message string.
Args:
storage_reader (StorageReader): storage reader.
provider_identifier (str): EventLog provider identifier.
log_source (str): EventLog source, such as "Application Error".
message_identifier (int): message identifier.
event_version (int): event version or None if not set.
Returns:
str: message string or None if not available.
"""
if self._environment_variables is None:
self._ReadEnvironmentVariables(storage_reader)
if self._windows_eventlog_providers is None:
self._ReadWindowsEventLogProviders(storage_reader)
if self._windows_eventlog_message_files is None:
self._ReadWindowsEventLogMessageFiles(storage_reader)
provider = None
if provider_identifier:
lookup_key = provider_identifier.lower()
provider = self._windows_eventlog_providers.get(lookup_key, None)
if not provider:
lookup_key = log_source.lower()
provider = self._windows_eventlog_providers.get(lookup_key, None)
provider = self._windows_eventlog_providers.get(lookup_key, None)
if not provider:
return None
if not storage_reader.HasAttributeContainers(
'windows_eventlog_message_string'):
return None
# Map the event identifier to a message identifier as defined by the
# WEVT_TEMPLATE event definition.
if provider_identifier and storage_reader.HasAttributeContainers(
'windows_wevt_template_event'):
# TODO: add message_file_identifiers to filter_expression
filter_expression = (
'provider_identifier == "{0:s}" and identifier == {1:d}').format(
provider_identifier, message_identifier)
if event_version is not None:
filter_expression = '{0:s} and version == {1:d}'.format(
filter_expression, event_version)
for event_definition in storage_reader.GetAttributeContainers(
'windows_wevt_template_event', filter_expression=filter_expression):
logger.debug(
'Message: 0x{0:08x} of provider: {1:s} maps to: 0x{2:08x}'.format(
message_identifier, provider_identifier,
event_definition.message_identifier))
message_identifier = event_definition.message_identifier
break
message_file_identifiers = []
for windows_path in provider.event_message_files or []:
path, filename = path_helper.PathHelper.GetWindowsSystemPath(
windows_path, self._environment_variables)
lookup_path = '\\'.join([path, filename]).lower()
message_file_identifier = self._windows_eventlog_message_files.get(
lookup_path, None)
if message_file_identifier:
message_file_identifier = message_file_identifier.CopyToString()
message_file_identifiers.append(message_file_identifier)
mui_filename = '{0:s}.mui'.format(filename)
lookup_path = '\\'.join([path, self._language_tag, mui_filename]).lower()
message_file_identifier = self._windows_eventlog_message_files.get(
lookup_path, None)
if message_file_identifier:
message_file_identifier = message_file_identifier.CopyToString()
message_file_identifiers.append(message_file_identifier)
if not message_file_identifiers:
logger.warning(
'No message file for message: 0x{0:08x} of provider: {1:s}'.format(
message_identifier, lookup_key))
return None
message_strings = []
# TODO: add message_file_identifiers to filter_expression
filter_expression = (
'language_identifier == {0:d} and '
'message_identifier == {1:d}').format(
self._lcid, message_identifier)
for message_string in storage_reader.GetAttributeContainers(
'windows_eventlog_message_string',
filter_expression=filter_expression):
identifier = message_string.GetMessageFileIdentifier()
identifier = identifier.CopyToString()
if identifier in message_file_identifiers:
message_strings.append(message_string)
if not message_strings:
logger.warning((
'No message string for message: 0x{0:08x} of provider: '
'{1:s}').format(message_identifier, lookup_key))
return None
return message_strings[0].string
def _ReadWindowsEventLogProviders(self, storage_reader):
"""Reads the Windows EventLog providers.
Args:
storage_reader (StorageReader): storage reader.
"""
self._windows_eventlog_providers = {}
if storage_reader.HasAttributeContainers('windows_eventlog_provider'):
for provider in storage_reader.GetAttributeContainers(
'windows_eventlog_provider'):
if provider.identifier:
self._windows_eventlog_providers[provider.identifier] = provider
for log_source in provider.log_sources:
log_source = log_source.lower()
self._windows_eventlog_providers[log_source] = provider
[docs] def GetMessageString(
self, provider_identifier, log_source, message_identifier, event_version):
"""Retrieves a specific Windows EventLog message string.
Args:
provider_identifier (str): EventLog provider identifier.
log_source (str): EventLog source, such as "Application Error".
message_identifier (int): message identifier.
event_version (int): event version or None if not set.
Returns:
str: message string or None if not available.
"""
message_string = self._GetCachedMessageString(
provider_identifier, log_source, message_identifier, event_version)
if not message_string:
if self._storage_reader and self._storage_reader.HasAttributeContainers(
'windows_eventlog_provider'):
message_string = self._ReadWindowsEventLogMessageString(
self._storage_reader, provider_identifier, log_source,
message_identifier, event_version)
else:
message_string = self._GetWinevtRcDatabaseMessageString(
log_source, message_identifier)
if message_string:
self._CacheMessageString(
provider_identifier, log_source, message_identifier, event_version,
message_string)
return message_string