277 lines
9.3 KiB
Python
277 lines
9.3 KiB
Python
#!/usr/bin/python
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# -*- coding: utf-8 -*-
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#
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# Copyright 2014 The Plaso Project Authors.
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# Please see the AUTHORS file for details on individual authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""This file contains the ASL securityd log plaintext parser."""
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import datetime
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import logging
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import pyparsing
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from plaso.events import time_events
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from plaso.lib import eventdata
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from plaso.lib import timelib
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from plaso.parsers import manager
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from plaso.parsers import text_parser
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__author__ = 'Joaquin Moreno Garijo (Joaquin.MorenoGarijo.2013@live.rhul.ac.uk)'
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# INFO:
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# http://opensource.apple.com/source/Security/Security-55471/sec/securityd/
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class MacSecuritydLogEvent(time_events.TimestampEvent):
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"""Convenience class for a ASL securityd line event."""
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DATA_TYPE = 'mac:asl:securityd:line'
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def __init__(
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self, timestamp, structure, sender, sender_pid,
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security_api, caller, message):
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"""Initializes the event object.
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Args:
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timestamp: The timestamp time value, epoch.
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structure: Structure with the parse fields.
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level: String with the text representation of the priority level.
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facility: String with the ASL facility.
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sender: String with the name of the sender.
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sender_pid: Process id of the sender.
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security_api: Securityd function name.
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caller: The caller field, a string containing two hex numbers.
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message: String with the ASL message.
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"""
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super(MacSecuritydLogEvent, self).__init__(
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timestamp,
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eventdata.EventTimestamp.ADDED_TIME)
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self.timestamp = timestamp
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self.level = structure.level
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self.sender_pid = sender_pid
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self.facility = structure.facility
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self.sender = sender
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self.security_api = security_api
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self.caller = caller
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self.message = message
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class MacSecuritydLogParser(text_parser.PyparsingSingleLineTextParser):
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"""Parses the securityd file that contains logs from the security daemon."""
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NAME = 'mac_securityd'
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DESCRIPTION = u'Parser for Mac OS X securityd log files.'
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ENCODING = u'utf-8'
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# Default ASL Securityd log.
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SECURITYD_LINE = (
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text_parser.PyparsingConstants.MONTH.setResultsName('month') +
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text_parser.PyparsingConstants.ONE_OR_TWO_DIGITS.setResultsName('day') +
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text_parser.PyparsingConstants.TIME.setResultsName('time') +
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pyparsing.CharsNotIn(u'[').setResultsName('sender') +
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pyparsing.Literal(u'[').suppress() +
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text_parser.PyparsingConstants.PID.setResultsName('sender_pid') +
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pyparsing.Literal(u']').suppress() +
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pyparsing.Literal(u'<').suppress() +
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pyparsing.CharsNotIn(u'>').setResultsName('level') +
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pyparsing.Literal(u'>').suppress() +
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pyparsing.Literal(u'[').suppress() +
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pyparsing.CharsNotIn(u'{').setResultsName('facility') +
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pyparsing.Literal(u'{').suppress() +
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pyparsing.Optional(pyparsing.CharsNotIn(
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u'}').setResultsName('security_api')) +
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pyparsing.Literal(u'}').suppress() +
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pyparsing.Optional(pyparsing.CharsNotIn(u']:').setResultsName('caller')) +
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pyparsing.Literal(u']:').suppress() +
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pyparsing.SkipTo(pyparsing.lineEnd).setResultsName('message'))
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# Repeated line.
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REPEATED_LINE = (
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text_parser.PyparsingConstants.MONTH.setResultsName('month') +
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text_parser.PyparsingConstants.ONE_OR_TWO_DIGITS.setResultsName('day') +
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text_parser.PyparsingConstants.TIME.setResultsName('time') +
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pyparsing.Literal(u'--- last message repeated').suppress() +
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text_parser.PyparsingConstants.INTEGER.setResultsName('times') +
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pyparsing.Literal(u'time ---').suppress())
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# Define the available log line structures.
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LINE_STRUCTURES = [
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('logline', SECURITYD_LINE),
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('repeated', REPEATED_LINE)]
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def __init__(self):
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"""Initializes a parser object."""
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super(MacSecuritydLogParser, self).__init__()
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self._year_use = 0
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self._last_month = None
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self.previous_structure = None
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def VerifyStructure(self, parser_context, line):
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"""Verify that this file is a ASL securityd log file.
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Args:
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parser_context: A parser context object (instance of ParserContext).
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line: A single line from the text file.
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Returns:
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True if this is the correct parser, False otherwise.
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"""
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try:
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line = self.SECURITYD_LINE.parseString(line)
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except pyparsing.ParseException:
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logging.debug(u'Not a ASL securityd log file')
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return False
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# Check if the day, month and time is valid taking a random year.
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month = timelib.MONTH_DICT.get(line.month.lower())
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if not month:
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return False
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if self._GetTimestamp(line.day, month, 2012, line.time) == 0:
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return False
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return True
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def ParseRecord(self, parser_context, key, structure):
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"""Parse each record structure and return an EventObject if applicable.
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Args:
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parser_context: A parser context object (instance of ParserContext).
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key: An identification string indicating the name of the parsed
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structure.
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structure: A pyparsing.ParseResults object from a line in the
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log file.
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Returns:
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An event object (instance of EventObject) or None.
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"""
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if key == 'repeated' or key == 'logline':
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return self._ParseLogLine(parser_context, structure, key)
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else:
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logging.warning(
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u'Unable to parse record, unknown structure: {0:s}'.format(key))
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def _ParseLogLine(self, parser_context, structure, key):
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"""Parse a logline and store appropriate attributes.
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Args:
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parser_context: A parser context object (instance of ParserContext).
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key: An identification string indicating the name of the parsed
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structure.
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structure: A pyparsing.ParseResults object from a line in the
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log file.
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Returns:
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An event object (instance of EventObject) or None.
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"""
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# TODO: improving this to get a valid year.
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if not self._year_use:
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self._year_use = parser_context.year
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if not self._year_use:
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# Get from the creation time of the file.
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self._year_use = self._GetYear(
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self.file_entry.GetStat(), parser_context.timezone)
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# If fail, get from the current time.
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if not self._year_use:
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self._year_use = timelib.GetCurrentYear()
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# Gap detected between years.
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month = timelib.MONTH_DICT.get(structure.month.lower())
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if not self._last_month:
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self._last_month = month
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if month < self._last_month:
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self._year_use += 1
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timestamp = self._GetTimestamp(
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structure.day,
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month,
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self._year_use,
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structure.time)
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if not timestamp:
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logging.debug(u'Invalid timestamp {0:s}'.format(structure.timestamp))
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return
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self._last_month = month
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if key == 'logline':
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self.previous_structure = structure
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message = structure.message
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else:
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times = structure.times
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structure = self.previous_structure
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message = u'Repeated {0:d} times: {1:s}'.format(
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times, structure.message)
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# It uses CarsNotIn structure which leaves whitespaces
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# at the beginning of the sender and the caller.
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sender = structure.sender.strip()
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caller = structure.caller.strip()
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if not caller:
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caller = 'unknown'
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if not structure.security_api:
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security_api = u'unknown'
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else:
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security_api = structure.security_api
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return MacSecuritydLogEvent(
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timestamp, structure, sender, structure.sender_pid, security_api,
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caller, message)
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def _GetTimestamp(self, day, month, year, time):
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"""Gets a timestamp from a pyparsing ParseResults timestamp.
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This is a timestamp_string as returned by using
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text_parser.PyparsingConstants structures:
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08, Nov, [20, 36, 37]
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Args:
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day: An integer representing the day.
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month: An integer representing the month.
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year: An integer representing the year.
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time: A list containing the hours, minutes, seconds.
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Returns:
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timestamp: A plaso timestamp.
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"""
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hours, minutes, seconds = time
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return timelib.Timestamp.FromTimeParts(
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year, month, day, hours, minutes, seconds)
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def _GetYear(self, stat, zone):
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"""Retrieves the year either from the input file or from the settings."""
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time = getattr(stat, 'crtime', 0)
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if not time:
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time = getattr(stat, 'ctime', 0)
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if not time:
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current_year = timelib.GetCurrentYear()
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logging.error((
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u'Unable to determine year of log file.\nDefaulting to: '
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u'{0:d}').format(current_year))
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return current_year
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try:
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timestamp = datetime.datetime.fromtimestamp(time, zone)
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except ValueError:
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current_year = timelib.GetCurrentYear()
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logging.error((
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u'Unable to determine year of log file.\nDefaulting to: '
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u'{0:d}').format(current_year))
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return current_year
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return timestamp.year
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manager.ParsersManager.RegisterParser(MacSecuritydLogParser)
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