fail2ban/fail2ban/server/datetemplate.py

282 lines
7.4 KiB
Python

# emacs: -*- mode: python; coding: utf-8; py-indent-offset: 4; indent-tabs-mode: t -*-
# vi: set ft=python sts=4 ts=4 sw=4 noet :
# This file is part of Fail2Ban.
#
# Fail2Ban is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# Fail2Ban is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Fail2Ban; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
# Author: Cyril Jaquier
#
__author__ = "Cyril Jaquier"
__copyright__ = "Copyright (c) 2004 Cyril Jaquier"
__license__ = "GPL"
import re
from abc import abstractmethod
from .strptime import reGroupDictStrptime, timeRE
from ..helpers import getLogger
logSys = getLogger(__name__)
class DateTemplate(object):
"""A template which searches for and returns a date from a log line.
This is an not functional abstract class which other templates should
inherit from.
Attributes
----------
name
regex
"""
def __init__(self):
self._name = ""
self._regex = ""
self._cRegex = None
self.hits = 0
self.lastUsed = 0
@property
def name(self):
"""Name assigned to template.
"""
return self._name
@name.setter
def name(self, name):
self._name = name
def getRegex(self):
return self._regex
def setRegex(self, regex, wordBegin=True):
"""Sets regex to use for searching for date in log line.
Parameters
----------
regex : str
The regex the template will use for searching for a date.
wordBegin : bool
Defines whether the regex should be modified to search at
beginning of a word, by adding "\\b" to start of regex.
Default True.
Raises
------
re.error
If regular expression fails to compile
"""
regex = regex.strip()
if (wordBegin and not re.search(r'^\^', regex)):
regex = r'\b' + regex
self._regex = regex
self._cRegex = re.compile(regex, re.UNICODE | re.IGNORECASE)
regex = property(getRegex, setRegex, doc=
"""Regex used to search for date.
""")
def matchDate(self, line):
"""Check if regex for date matches on a log line.
"""
dateMatch = self._cRegex.search(line)
return dateMatch
@abstractmethod
def getDate(self, line, dateMatch=None):
"""Abstract method, which should return the date for a log line
This should return the date for a log line, typically taking the
date from the part of the line which matched the templates regex.
This requires abstraction, therefore just raises exception.
Parameters
----------
line : str
Log line, of which the date should be extracted from.
Raises
------
NotImplementedError
Abstract method, therefore always returns this.
"""
raise NotImplementedError("getDate() is abstract")
class DateEpoch(DateTemplate):
"""A date template which searches for Unix timestamps.
This includes Unix timestamps which appear at start of a line, optionally
within square braces (nsd), or on SELinux audit log lines.
Attributes
----------
name
regex
"""
def __init__(self):
DateTemplate.__init__(self)
self.regex = "(?:^|(?P<square>(?<=^\[))|(?P<selinux>(?<=audit\()))\d{10}(?:\.\d{3,6})?(?(selinux)(?=:\d+\))(?(square)(?=\])))"
def getDate(self, line, dateMatch=None):
"""Method to return the date for a log line.
Parameters
----------
line : str
Log line, of which the date should be extracted from.
Returns
-------
(float, str)
Tuple containing a Unix timestamp, and the string of the date
which was matched and in turned used to calculated the timestamp.
"""
if not dateMatch:
dateMatch = self.matchDate(line)
if dateMatch:
# extract part of format which represents seconds since epoch
return (float(dateMatch.group()), dateMatch)
return None
class DatePatternRegex(DateTemplate):
"""Date template, with regex/pattern
Parameters
----------
pattern : str
Sets the date templates pattern.
Attributes
----------
name
regex
pattern
"""
_patternRE = r"%%(%%|[%s])" % "".join(timeRE.keys())
_patternName = {
'a': "DAY", 'A': "DAYNAME", 'b': "MON", 'B': "MONTH", 'd': "Day",
'H': "24hour", 'I': "12hour", 'j': "Yearday", 'm': "Month",
'M': "Minute", 'p': "AMPM", 'S': "Second", 'U': "Yearweek",
'w': "Weekday", 'W': "Yearweek", 'y': 'Year2', 'Y': "Year", '%': "%",
'z': "Zone offset", 'f': "Microseconds", 'Z': "Zone name"}
for _key in set(timeRE) - set(_patternName): # may not have them all...
_patternName[_key] = "%%%s" % _key
def __init__(self, pattern=None):
super(DatePatternRegex, self).__init__()
self._pattern = None
if pattern is not None:
self.pattern = pattern
@property
def pattern(self):
"""The pattern used for regex with strptime "%" time fields.
This should be a valid regular expression, of which matching string
will be extracted from the log line. strptime style "%" fields will
be replaced by appropriate regular expressions, or custom regex
groups with names as per the strptime fields can also be used
instead.
"""
return self._pattern
@pattern.setter
def pattern(self, pattern):
self._pattern = pattern
self._name = re.sub(
self._patternRE, r'%(\1)s', pattern) % self._patternName
super(DatePatternRegex, self).setRegex(
re.sub(self._patternRE, r'%(\1)s', pattern) % timeRE)
def setRegex(self, value):
raise NotImplementedError("Regex derived from pattern")
@DateTemplate.name.setter
def name(self, value):
raise NotImplementedError("Name derived from pattern")
def getDate(self, line, dateMatch=None):
"""Method to return the date for a log line.
This uses a custom version of strptime, using the named groups
from the instances `pattern` property.
Parameters
----------
line : str
Log line, of which the date should be extracted from.
Returns
-------
(float, str)
Tuple containing a Unix timestamp, and the string of the date
which was matched and in turned used to calculated the timestamp.
"""
if not dateMatch:
dateMatch = self.matchDate(line)
if dateMatch:
groupdict = dict(
(key, value)
for key, value in dateMatch.groupdict().iteritems()
if value is not None)
return reGroupDictStrptime(groupdict), dateMatch
class DateTai64n(DateTemplate):
"""A date template which matches TAI64N formate timestamps.
Attributes
----------
name
regex
"""
def __init__(self):
DateTemplate.__init__(self)
# We already know the format for TAI64N
# yoh: we should not add an additional front anchor
self.setRegex("@[0-9a-f]{24}", wordBegin=False)
def getDate(self, line, dateMatch=None):
"""Method to return the date for a log line.
Parameters
----------
line : str
Log line, of which the date should be extracted from.
Returns
-------
(float, str)
Tuple containing a Unix timestamp, and the string of the date
which was matched and in turned used to calculated the timestamp.
"""
if not dateMatch:
dateMatch = self.matchDate(line)
if dateMatch:
# extract part of format which represents seconds since epoch
value = dateMatch.group()
seconds_since_epoch = value[2:17]
# convert seconds from HEX into local time stamp
return (int(seconds_since_epoch, 16), dateMatch)
return None