fail2ban/server/filter.py

566 lines
14 KiB
Python

# 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
# Author: Cyril Jaquier
#
# $Revision: 605 $
__author__ = "Cyril Jaquier"
__version__ = "$Revision: 605 $"
__date__ = "$Date: 2007-08-08 00:11:34 +0200 (Wed, 08 Aug 2007) $"
__copyright__ = "Copyright (c) 2004 Cyril Jaquier"
__license__ = "GPL"
from failmanager import FailManager
from failticket import FailTicket
from jailthread import JailThread
from datedetector import DateDetector
from mytime import MyTime
from regex import Regex, RegexException
from failregex import FailRegex
import logging, re
# Gets the instance of the logger.
logSys = logging.getLogger("fail2ban.filter")
##
# Log reader class.
#
# This class reads a log file and detects login failures or anything else
# that matches a given regular expression. This class is instanciated by
# a Jail object.
class Filter(JailThread):
##
# Constructor.
#
# Initialize the filter object with default values.
# @param jail the jail object
def __init__(self, jail):
JailThread.__init__(self)
## The jail which contains this filter.
self.jail = jail
## The failures manager.
self.failManager = FailManager()
## The log file handler.
self.__crtHandler = None
self.__crtFilename = None
## The log file path.
self.__logPath = []
## The regular expression list matching the failures.
self.__failRegex = list()
## The regular expression list with expressions to ignore.
self.__ignoreRegex = list()
## The amount of time to look back.
self.__findTime = 6000
## The ignore IP list.
self.__ignoreIpList = []
## The last position of the file.
self.__lastPos = dict()
## The last date in tht log file.
self.__lastDate = dict()
self.dateDetector = DateDetector()
self.dateDetector.addDefaultTemplate()
logSys.info("Created Filter")
##
# Add a log file path
#
# @param path log file path
def addLogPath(self, path):
self.getLogPath().append(path)
# Initialize default values
self.__lastDate[path] = 0
self.__lastPos[path] = 0
##
# Delete a log path
#
# @param path the log file to delete
def delLogPath(self, path):
self.getLogPath().remove(path)
del self.__lastDate[path]
del self.__lastPos[path]
##
# Get the log file path
#
# @return log file path
def getLogPath(self):
return self.__logPath
##
# Check whether path is already monitored.
#
# @param path The path
# @return True if the path is already monitored else False
def containsLogPath(self, path):
try:
self.getLogPath().index(path)
return True
except ValueError:
return False
##
# Set the regular expression which matches the time.
#
# @param value the regular expression
def setTimeRegex(self, value):
self.dateDetector.setDefaultRegex(value)
logSys.info("Set default regex = %s" % value)
##
# Get the regular expression which matches the time.
#
# @return the regular expression
def getTimeRegex(self):
return self.dateDetector.getDefaultRegex()
##
# Set the time pattern.
#
# @param value the time pattern
def setTimePattern(self, value):
self.dateDetector.setDefaultPattern(value)
logSys.info("Set default pattern = %s" % value)
##
# Get the time pattern.
#
# @return the time pattern
def getTimePattern(self):
return self.dateDetector.getDefaultPattern()
##
# Add a regular expression which matches the failure.
#
# The regular expression can also match any other pattern than failures
# and thus can be used for many purporse.
# @param value the regular expression
def addFailRegex(self, value):
try:
regex = FailRegex(value)
self.__failRegex.append(regex)
except RegexException, e:
logSys.error(e)
def delFailRegex(self, index):
try:
del self.__failRegex[index]
except IndexError:
logSys.error("Cannot remove regular expression. Index %d is not "
"valid" % index)
##
# Get the regular expression which matches the failure.
#
# @return the regular expression
def getFailRegex(self):
failRegex = list()
for regex in self.__failRegex:
failRegex.append(regex.getRegex())
return failRegex
##
# Add the regular expression which matches the failure.
#
# The regular expression can also match any other pattern than failures
# and thus can be used for many purporse.
# @param value the regular expression
def addIgnoreRegex(self, value):
try:
regex = Regex(value)
self.__ignoreRegex.append(regex)
except RegexException, e:
logSys.error(e)
def delIgnoreRegex(self, index):
try:
del self.__ignoreRegex[index]
except IndexError:
logSys.error("Cannot remove regular expression. Index %d is not "
"valid" % index)
##
# Get the regular expression which matches the failure.
#
# @return the regular expression
def getIgnoreRegex(self):
ignoreRegex = list()
for regex in self.__ignoreRegex:
ignoreRegex.append(regex.getRegex())
return ignoreRegex
##
# Set the time needed to find a failure.
#
# This value tells the filter how long it has to take failures into
# account.
# @param value the time
def setFindTime(self, value):
self.__findTime = value
self.failManager.setMaxTime(value)
logSys.info("Set findtime = %s" % value)
##
# Get the time needed to find a failure.
#
# @return the time
def getFindTime(self):
return self.__findTime
##
# Set the maximum retry value.
#
# @param value the retry value
def setMaxRetry(self, value):
self.failManager.setMaxRetry(value)
logSys.info("Set maxRetry = %s" % value)
##
# Get the maximum retry value.
#
# @return the retry value
def getMaxRetry(self):
return self.failManager.getMaxRetry()
##
# Main loop.
#
# This function is the main loop of the thread. It checks if the
# file has been modified and looks for failures.
# @return True when the thread exits nicely
def run(self):
raise Exception("run() is abstract")
##
# Add an IP/DNS to the ignore list.
#
# IP addresses in the ignore list are not taken into account
# when finding failures. CIDR mask and DNS are also accepted.
# @param ip IP address to ignore
def addIgnoreIP(self, ip):
logSys.debug("Add " + ip + " to ignore list")
self.__ignoreIpList.append(ip)
def delIgnoreIP(self, ip):
logSys.debug("Remove " + ip + " from ignore list")
self.__ignoreIpList.remove(ip)
def getIgnoreIP(self):
return self.__ignoreIpList
##
# Check if IP address/DNS is in the ignore list.
#
# Check if the given IP address matches an IP address/DNS or a CIDR
# mask in the ignore list.
# @param ip IP address
# @return True if IP address is in ignore list
def inIgnoreIPList(self, ip):
for i in self.__ignoreIpList:
# An empty string is always false
if i == "":
return False
s = i.split('/', 1)
# IP address without CIDR mask
if len(s) == 1:
s.insert(1, '32')
s[1] = long(s[1])
try:
a = DNSUtils.cidr(s[0], s[1])
b = DNSUtils.cidr(ip, s[1])
except Exception:
# Check if IP in DNS
ips = DNSUtils.dnsToIp(i)
if ip in ips:
return True
else:
return False
if a == b:
return True
return False
##
# Open the log file.
def __openLogFile(self, filename):
""" Opens the log file specified on init.
"""
try:
self.__crtFilename = filename
self.__crtHandler = open(filename)
logSys.debug("Opened " + filename)
return True
except OSError:
logSys.error("Unable to open " + filename)
except IOError:
logSys.error("Unable to read " + filename +
". Please check permissions")
return False
##
# Close the log file.
def __closeLogFile(self):
self.__crtFilename = None
self.__crtHandler.close()
##
# Set the file position.
#
# Sets the file position. We must take care of log file rotation
# and reset the position to 0 in that case. Use the log message
# timestamp in order to detect this.
def __setFilePos(self):
line = self.__crtHandler.readline()
lastDate = self.__lastDate[self.__crtFilename]
lineDate = self.dateDetector.getUnixTime(line)
if lastDate < lineDate:
logSys.debug("Date " + `lastDate` + " is smaller than " + `lineDate`)
logSys.debug("Log rotation detected for " + self.__crtFilename)
self.__lastPos[self.__crtFilename] = 0
lastPos = self.__lastPos[self.__crtFilename]
logSys.debug("Setting file position to " + `lastPos` + " for " +
self.__crtFilename)
self.__crtHandler.seek(lastPos)
##
# Get the file position.
def __getFilePos(self):
return self.__crtHandler.tell()
##
# Gets all the failure in the log file.
#
# Gets all the failure in the log file which are newer than
# MyTime.time()-self.findTime. When a failure is detected, a FailTicket
# is created and is added to the FailManager.
def getFailures(self, filename):
# Try to open log file.
if not self.__openLogFile(filename):
logSys.error("Unable to get failures in " + filename)
return False
self.__setFilePos()
lastLine = None
for line in self.__crtHandler:
if not self._isActive():
# The jail has been stopped
break
try:
# Decode line to UTF-8
line = line.decode('utf-8')
except UnicodeDecodeError:
pass
if not self.dateDetector.matchTime(line):
# There is no valid time in this line
continue
lastLine = line
for element in self.findFailure(line):
ip = element[0]
unixTime = element[1]
if unixTime < MyTime.time()-self.__findTime:
break
if self.inIgnoreIPList(ip):
logSys.debug("Ignore "+ip)
continue
logSys.debug("Found "+ip)
self.failManager.addFailure(FailTicket(ip, unixTime))
self.__lastPos[filename] = self.__getFilePos()
if lastLine:
self.__lastDate[filename] = self.dateDetector.getUnixTime(lastLine)
self.__closeLogFile()
return True
##
# Returns true if the line should be ignored.
#
# Uses ignoreregex.
# @param line: the line
# @return: a boolean
def ignoreLine(self, line):
for ignoreRegex in self.__ignoreRegex:
ignoreRegex.search(line)
if ignoreRegex.hasMatched():
return True
return False
##
# Finds the failure in a line.
#
# Uses the failregex pattern to find it and timeregex in order
# to find the logging time.
# @return a dict with IP and timestamp.
def findFailure(self, line):
failList = list()
# Checks if we must ignore this line.
if self.ignoreLine(line):
# The ignoreregex matched. Return.
return failList
# Iterates over all the regular expressions.
for failRegex in self.__failRegex:
failRegex.search(line)
if failRegex.hasMatched():
# The failregex matched.
date = self.dateDetector.getUnixTime(line)
if date == None:
logSys.debug("Found a match but no valid date/time found "
+ "for " + line + ". Please contact the "
+ "author in order to get support for this "
+ "format")
else:
try:
host = failRegex.getHost()
ipMatch = DNSUtils.textToIp(host)
if ipMatch:
for ip in ipMatch:
failList.append([ip, date])
# We matched a regex, it is enough to stop.
break
except RegexException, e:
logSys.error(e)
return failList
##
# Get the status of the filter.
#
# Get some informations about the filter state such as the total
# number of failures.
# @return a list with tuple
def status(self):
ret = [("Currently failed", self.failManager.size()),
("Total failed", self.failManager.getFailTotal())]
return ret
##
# Utils class for DNS and IP handling.
#
# This class contains only static methods used to handle DNS and IP
# addresses.
import socket, struct
class DNSUtils:
DNS_CRE = re.compile("(?:(?:\w|-)+\.){2,}\w+")
IP_CRE = re.compile("(?:\d{1,3}\.){3}\d{1,3}")
@staticmethod
def dnsToIp(dns):
""" Convert a DNS into an IP address using the Python socket module.
Thanks to Kevin Drapel.
"""
try:
return socket.gethostbyname_ex(dns)[2]
except socket.gaierror:
logSys.warn("Unable to find a corresponding IP address for %s"
% dns)
return list()
@staticmethod
def searchIP(text):
""" Search if an IP address if directly available and return
it.
"""
match = DNSUtils.IP_CRE.match(text)
if match:
return match
else:
return None
@staticmethod
def isValidIP(string):
""" Return true if str is a valid IP
"""
s = string.split('/', 1)
try:
socket.inet_aton(s[0])
return True
except socket.error:
return False
@staticmethod
def textToIp(text):
""" Return the IP of DNS found in a given text.
"""
ipList = list()
# Search for plain IP
plainIP = DNSUtils.searchIP(text)
if not plainIP == None:
plainIPStr = plainIP.group(0)
if DNSUtils.isValidIP(plainIPStr):
ipList.append(plainIPStr)
if not ipList:
# Try to get IP from possible DNS
ip = DNSUtils.dnsToIp(text)
for e in ip:
ipList.append(e)
return ipList
@staticmethod
def cidr(i, n):
""" Convert an IP address string with a CIDR mask into a 32-bit
integer.
"""
# 32-bit IPv4 address mask
MASK = 0xFFFFFFFFL
return ~(MASK >> n) & MASK & DNSUtils.addr2bin(i)
@staticmethod
def addr2bin(string):
""" Convert a string IPv4 address into an unsigned integer.
"""
return struct.unpack("!L", socket.inet_aton(string))[0]
@staticmethod
def bin2addr(addr):
""" Convert a numeric IPv4 address into string n.n.n.n form.
"""
return socket.inet_ntoa(struct.pack("!L", addr))