mirror of https://github.com/fail2ban/fail2ban
578 lines
17 KiB
Python
Executable File
578 lines
17 KiB
Python
Executable File
# This file is part of Fail2Ban.
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#
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# Fail2Ban is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# Fail2Ban is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with Fail2Ban; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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# Author: Cyril Jaquier
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# Modified by: Yaroslav Halchenko (SYSLOG, findtime)
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#
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# $Revision: 1.21 $
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__author__ = "Cyril Jaquier"
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__version__ = "$Revision: 1.21 $"
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__date__ = "$Date: 2005/11/20 17:07:47 $"
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__copyright__ = "Copyright (c) 2004 Cyril Jaquier"
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__license__ = "GPL"
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import time, sys, getopt, os, string, signal, logging, logging.handlers, copy
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from ConfigParser import *
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from version import version
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from firewall.firewall import Firewall
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from logreader.logreader import LogReader
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from confreader.configreader import ConfigReader
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from utils.mail import Mail
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from utils.pidlock import PIDLock
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from utils.dns import *
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from utils.process import *
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# Get the instance of the logger.
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logSys = logging.getLogger("fail2ban")
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# Get PID lock file instance
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pidLock = PIDLock()
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# Global variables
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logFwList = list()
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conf = dict()
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def dispUsage():
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""" Prints Fail2Ban command line options and exits
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"""
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print "Usage: "+sys.argv[0]+" [OPTIONS]"
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print
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print "Fail2Ban v"+version+" reads log file that contains password failure report"
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print "and bans the corresponding IP addresses using firewall rules."
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print
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print " -b start in background"
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print " -d start in debug mode"
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print " -c <FILE> read configuration file FILE"
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print " -p <FILE> create PID lock in FILE"
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print " -h display this help message"
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print " -i <IP(s)> IP(s) to ignore"
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print " -k kill a currently running instance"
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print " -r <VALUE> allow a max of VALUE password failures [maxfailures]"
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print " -t <TIME> ban IP for TIME seconds [bantime]"
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print " -f <TIME> lifetime in seconds of failed entry [findtime]"
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print " -e <NAMEs> enable sections listed in NAMEs (coma or colon separated)"
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print " -v verbose. Use twice for greater effect"
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print " -V print software version"
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print
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print "Report bugs to <lostcontrol@users.sourceforge.net>"
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sys.exit(0)
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def dispVersion():
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""" Prints Fail2Ban version and exits
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"""
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print sys.argv[0]+" "+version
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sys.exit(0)
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def checkForRoot():
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""" Check for root user.
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"""
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uid = `os.getuid()`
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if uid == '0':
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return True
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else:
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return False
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def sigTERMhandler(signum, frame):
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""" Handles the TERM signal when in daemon mode in order to
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exit properly.
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"""
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logSys.debug("Signal handler called with sig "+`signum`)
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killApp()
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def setFwMustCheck(value):
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""" Set the mustCheck value of the firewalls (True/False)
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"""
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for element in logFwList:
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element[2].setMustCheck(value)
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def initializeFwRules():
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""" Initializes firewalls by running cmdstart and then
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fwstart for each section
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"""
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# Execute global start command
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executeCmd(conf["cmdstart"], conf["debug"])
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# Execute start command of each section
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for element in logFwList:
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element[2].initialize(conf["debug"])
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def reBan():
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""" For each section asks the Firewall to reban known IPs
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"""
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for element in logFwList:
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element[2].reBan(conf["debug"])
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def restoreFwRules():
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""" Flush the ban list
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"""
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logSys.warn("Restoring firewall rules...")
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try:
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for element in logFwList:
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# Execute end command of each section
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element[2].restore(conf["debug"])
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# Execute global end command
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executeCmd(conf["cmdend"], conf["debug"])
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except ExternalError:
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# nothing bad really - we can survive :-)
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pass
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def killApp():
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""" Flush the ban list, remove the PID lock file and exit
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nicely.
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"""
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# Restore Fw rules
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restoreFwRules()
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# Remove the PID lock
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pidLock.remove()
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logSys.info("Exiting...")
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logging.shutdown()
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sys.exit(0)
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def isEnabledSection(b, name):
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""" Uses @b or searches @name in the conf['enabledsections'] to
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determine if section is enabled. Removes also a value from the
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list if it was there
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Decided to place as a function to avoid duplication between
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MAIL and regular sections
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"""
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v = b
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if (name.upper() in conf["enabledsections"]):
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v = True
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conf["enabledsections"].remove(name.upper())
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return v
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def getCmdLineOptions(optList):
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""" Gets the command line options
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"""
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# enabledsections can be defined just from the command line
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conf["enabledsections"] = []
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for opt in optList:
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if opt[0] == "-v":
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conf["verbose"] = conf["verbose"] + 1
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if opt[0] == "-b":
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conf["background"] = True
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if opt[0] == "-d":
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conf["debug"] = True
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if opt[0] == "-t":
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try:
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conf["bantime"] = int(opt[1])
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except ValueError:
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logSys.warn("banTime must be an integer")
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logSys.warn("Using default value")
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if opt[0] == "-f":
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try:
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conf["findtime"] = int(opt[1])
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except ValueError:
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logSys.warn("findTime must be an integer")
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logSys.warn("Using default value")
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if opt[0] == "-i":
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conf["ignoreip"] = opt[1]
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if opt[0] == "-r":
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conf["maxfailures"] = int(opt[1])
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if opt[0] == "-p":
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conf["pidlock"] = opt[1]
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if opt[0] == "-k":
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conf["kill"] = True
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if opt[0] == "-e":
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conf["enabledsections"] = map(lambda x: x.upper(),
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re.split("[:, \t\n]", opt[1]))
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def main():
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""" Fail2Ban main function
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"""
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# Add the default logging handler
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stdout = logging.StreamHandler(sys.stdout)
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logSys.addHandler(stdout)
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# Default formatter
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formatterstring='%(levelname)s: %(message)s'
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formatter = logging.Formatter('%(asctime)s ' + formatterstring)
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stdout.setFormatter(formatter)
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conf["kill"] = False
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conf["verbose"] = 0
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conf["conffile"] = "/etc/fail2ban.conf"
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# Reads the command line options.
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try:
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cmdOpts = 'hvVbdkc:t:f:i:r:p:e:'
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cmdLongOpts = ['help', 'version']
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optList, args = getopt.getopt(sys.argv[1:], cmdOpts, cmdLongOpts)
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except getopt.GetoptError:
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dispUsage()
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# Pre-parsing of command line options for the -c option
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for opt in optList:
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if opt[0] == "-c":
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conf["conffile"] = opt[1]
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if opt[0] in ["-h", "--help"]:
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dispUsage()
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if opt[0] in ["-V", "--version"]:
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dispVersion()
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# Reads the config file and create a LogReader instance for
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# each log file to check.
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confReader = ConfigReader(conf["conffile"]);
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confReader.openConf()
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# Options
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optionValues = (["bool", "background", False],
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["str", "logtargets", "/var/log/fail2ban.log"],
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["str", "syslog-target", "/dev/log"],
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["int", "syslog-facility", 1],
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["bool", "debug", False],
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["int", "verbose", conf["verbose"]],
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["str", "pidlock", "/var/run/fail2ban.pid"],
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["int", "maxfailures", 5],
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["int", "bantime", 600],
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["int", "findtime", 600],
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["str", "ignoreip", ""],
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["int", "polltime", 1],
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["str", "cmdstart", ""],
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["str", "cmdend", ""],
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["int", "reinittime", 100],
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["int", "maxreinits", 100])
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# Gets global configuration options
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conf.update(confReader.getLogOptions("DEFAULT", optionValues))
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# Gets command line options
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getCmdLineOptions(optList)
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# Now we need to update confReader.configParser with 'commandline'
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# overwritten parameters. There is no way to assign configParser
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# with defaults (as I thought before) below in the code: thus defaults
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# have to be overridden
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for t, label, v in optionValues:
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confReader.setValue("DEFAULT", label, `conf[label]`)
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# PID lock
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pidLock.setPath(conf["pidlock"])
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# Now we can kill properly a running instance if needed
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if conf["kill"]:
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pid = pidLock.exists()
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if pid:
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killPID(int(pid))
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logSys.warn("Killed Fail2Ban with PID "+pid)
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sys.exit(0)
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else:
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logSys.error("No running Fail2Ban found")
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sys.exit(-1)
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# Start Fail2Ban in daemon mode
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if conf["background"]:
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retCode = createDaemon()
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signal.signal(signal.SIGTERM, sigTERMhandler)
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if not retCode:
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logSys.error("Unable to start daemon")
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sys.exit(-1)
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# Process some options
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# First setup Log targets
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# Bug fix for #1234699
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os.umask(0077)
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for target in conf["logtargets"].split():
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# target formatter
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# By default global formatter is taken. Is different for SYSLOG
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tformatter = formatter
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if target == "STDERR":
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hdlr = logging.StreamHandler(sys.stderr)
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elif target == "SYSLOG":
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# SYSLOG target can be either
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# a socket (file, so it starts with /)
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# or hostname
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# or hostname:port
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syslogtargets = re.findall("(/[\w/]*)|([^/ ][^: ]*)(:(\d+)){,1}",
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conf["syslog-target"])
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# we are waiting for a single match
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syslogtargets = syslogtargets[0]
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# assign facility if it was defined
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if conf["syslog-facility"] < 0:
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facility = handlers.SysLogHandler.LOG_USER
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else:
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facility = conf["syslog-facility"]
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if len(syslogtargets) == 0: # everything default
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hdlr = logging.handlers.SysLogHandler()
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else:
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if not ( syslogtargets[0] == "" ): # got socket
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syslogtarget = syslogtargets[0]
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else: # got hostname and maybe a port
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if syslogtargets[3] == "": # no port specified
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port = 514
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else:
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port = int(syslogtargets[3])
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syslogtarget = (syslogtargets[1], port)
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hdlr = logging.handlers.SysLogHandler(syslogtarget, facility)
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tformatter = logging.Formatter("fail2ban[%(process)d]: " +
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formatterstring);
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else:
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# Target should be a file
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try:
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open(target, "a")
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hdlr = logging.FileHandler(target)
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except IOError:
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logSys.error("Unable to log to " + target)
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continue
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# Set formatter and add handler to logger
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hdlr.setFormatter(tformatter)
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logSys.addHandler(hdlr)
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# Process some options
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# Verbose level
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if conf["verbose"]:
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logSys.warn("Verbose level is "+`conf["verbose"]`)
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if conf["verbose"] == 1:
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logSys.setLevel(logging.INFO)
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elif conf["verbose"] > 1:
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logSys.setLevel(logging.DEBUG)
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# Set debug log level
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if conf["debug"]:
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logSys.setLevel(logging.DEBUG)
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formatterstring = ('%(levelname)s: [%(filename)s (%(lineno)d)] ' +
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'%(message)s')
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formatter = logging.Formatter("%(asctime)s " + formatterstring)
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stdout.setFormatter(formatter)
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logSys.warn("DEBUG MODE: FIREWALL COMMANDS ARE _NOT_ EXECUTED BUT " +
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"ONLY DISPLAYED IN THE LOG MESSAGES")
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# Ignores IP list
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ignoreIPList = conf["ignoreip"].split(' ')
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# Checks for root user. This is necessary because log files
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# are owned by root and firewall needs root access.
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if not checkForRoot():
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logSys.error("You must be root")
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if not conf["debug"]:
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sys.exit(-1)
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# Checks that no instance of Fail2Ban is currently running.
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pid = pidLock.exists()
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if pid:
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logSys.error("Fail2Ban already running with PID "+pid)
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sys.exit(-1)
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else:
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ret = pidLock.create()
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if not ret:
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# Unable to create PID lock. Exit
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sys.exit(-1)
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logSys.debug("ConfFile is " + conf["conffile"])
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logSys.debug("BanTime is " + `conf["bantime"]`)
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logSys.debug("FindTime is " + `conf["findtime"]`)
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logSys.debug("MaxFailure is " + `conf["maxfailures"]`)
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# Options
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optionValues = (["bool", "enabled", False],
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["str", "host", "localhost"],
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["int", "port", "25"],
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["str", "from", "root"],
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["str", "to", "root"],
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["bool", "localtime", False],
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["str", "subject", "[Fail2Ban] Banned <ip>"],
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["str", "message", "Fail2Ban notification"])
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# Gets global configuration options
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mailConf = confReader.getLogOptions("MAIL", optionValues)
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# Create mailer if enabled
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if isEnabledSection(mailConf["enabled"], "MAIL"):
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logSys.debug("Mail enabled")
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mail = Mail(mailConf["host"], mailConf["port"])
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mail.setFromAddr(mailConf["from"])
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mail.setToAddr(mailConf["to"])
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mail.setLocalTimeFlag(mailConf["localtime"])
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logSys.debug("to: " + mailConf["to"] + " from: " + mailConf["from"])
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# Options
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optionValues = (["bool", "enabled", False],
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["str", "logfile", "/dev/null"],
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["int", "maxfailures", conf["maxfailures"]],
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["int", "bantime", conf["bantime"]],
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["int", "findtime", conf["findtime"]],
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["str", "timeregex", ""],
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["str", "timepattern", ""],
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["str", "failregex", ""],
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["str", "fwstart", ""],
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["str", "fwend", ""],
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["str", "fwban", ""],
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["str", "fwunban", ""],
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["str", "fwcheck", ""])
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logSys.info("Fail2Ban v" + version + " is running")
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enabledSections = []
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# Gets the options of each sections
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for t in confReader.getSections():
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l = confReader.getLogOptions(t, optionValues)
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if isEnabledSection(l["enabled"], t):
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# Creates a logreader object
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enabledSections.append(t)
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lObj = LogReader(l["logfile"], l["timeregex"], l["timepattern"],
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l["failregex"], l["maxfailures"], l["findtime"])
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# Creates a firewall object
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fObj = Firewall(l["fwstart"], l["fwend"], l["fwban"], l["fwunban"],
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l["fwcheck"], l["bantime"])
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# "Name" the firewall
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fObj.setSection(t)
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# Links them into a list. I'm not really happy
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# with this :/
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logFwList.append([t, lObj, fObj, dict()])
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logSys.info("Enabled sections: %s"%enabledSections)
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# Warn about such "bad" sections
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if len(conf["enabledsections"])>0:
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logSys.warn("Sections %s defined in command "%conf["enabledsections"] +
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"line were not found in config, thus ignored")
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# We add 127.0.0.1 to the ignore list has we do not want
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# to be ban ourself.
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for element in logFwList:
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element[1].addIgnoreIP("127.0.0.1")
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while len(ignoreIPList) > 0:
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ip = ignoreIPList.pop()
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# Bug fix for #1239557
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if isValidIP(ip):
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for element in logFwList:
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element[1].addIgnoreIP(ip)
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else:
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logSys.warn(ip + " is not a valid IP address")
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# Startup loop -- necessary to avoid crash if it takes time for iptables
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# to startup
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# To avoid introduction of new config options, reusing maxreinits and polltime
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reinits = 0
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while True:
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try:
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initializeFwRules()
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break
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except ExternalError, e:
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reinits += 1
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logSys.warn(e)
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if conf["maxreinits"] < 0 or (reinits < conf["maxreinits"]):
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logSys.warn("#%d attempt to initialize the firewalls"%reinits)
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else:
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logSys.error("Exiting: Too many attempts to initialize the firewall")
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killApp()
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time.sleep(conf["polltime"])
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# try to reinit once if it fails immediately
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lastReinitTime = time.time() - conf["reinittime"] - 1
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reinits = 0
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# Main loop
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while True:
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try:
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sys.stdout.flush()
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sys.stderr.flush()
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# Checks if some IP have to be remove from ban
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# list.
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for element in logFwList:
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element[2].checkForUnBan(conf["debug"])
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# If the log file has not been modified since the
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# last time, we sleep for 1 second. This is active
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# polling so not very effective.
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modList = list()
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for element in logFwList:
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if element[1].isModified():
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modList.append(element)
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if len(modList) == 0:
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time.sleep(conf["polltime"])
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continue
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# Gets the failure list from the log file. For a given IP,
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# takes only the service which has the most password failures.
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for element in modList:
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e = element[1].getFailures()
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for key in e.iterkeys():
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if element[3].has_key(key):
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element[3][key] = (element[3][key][0] + e[key][0],
|
|
e[key][1])
|
|
else:
|
|
element[3][key] = (e[key][0], e[key][1])
|
|
|
|
# Remove the oldest failure attempts from the global list.
|
|
# We iterate the failure list and ban IP that make
|
|
# *retryAllowed* login failures.
|
|
unixTime = time.time()
|
|
for element in logFwList:
|
|
fails = element[3].copy()
|
|
findTime = element[1].getFindTime()
|
|
for attempt in fails:
|
|
failTime = fails[attempt][1]
|
|
if failTime < unixTime - findTime:
|
|
del element[3][attempt]
|
|
elif fails[attempt][0] >= element[1].getMaxRetry():
|
|
aInfo = {"section": element[0],
|
|
"ip": attempt,
|
|
"failures": element[3][attempt][0],
|
|
"failtime": failTime}
|
|
logSys.info(element[0] + ": " + aInfo["ip"] +
|
|
" has " + `aInfo["failures"]` +
|
|
" login failure(s). Banned.")
|
|
element[2].addBanIP(aInfo, conf["debug"])
|
|
# Send a mail notification
|
|
if 'mail' in locals():
|
|
mail.sendmail(mailConf["subject"],
|
|
mailConf["message"], aInfo)
|
|
del element[3][attempt]
|
|
except ExternalError, e:
|
|
# Something wrong while dealing with Iptables.
|
|
# May be chain got removed?
|
|
reinits += 1
|
|
logSys.error(e)
|
|
if ((unixTime - lastReinitTime > conf["reinittime"]) and
|
|
((conf["maxreinits"] < 0) or (reinits < conf["maxreinits"]))):
|
|
logSys.warn("#%d reinitialization of firewalls"%reinits)
|
|
lastReinitTime = unixTime
|
|
else:
|
|
logSys.error("Exiting: reinits follow too often, or too many " +
|
|
"reinit attempts")
|
|
killApp()
|
|
# We already failed runCheck so disable it until
|
|
# restoring a safe state
|
|
setFwMustCheck(False)
|
|
# save firewalls to keep a list of IPs for rebanning
|
|
logFwListCopy = copy.deepcopy(logFwList)
|
|
try:
|
|
# restore as much as possible
|
|
restoreFwRules()
|
|
# reinitialize all the chains
|
|
initializeFwRules()
|
|
# restore the lists of baned IPs
|
|
logFwList.__init__(logFwListCopy)
|
|
# reBan known IPs
|
|
reBan()
|
|
# Now we can enable the runCheck test again
|
|
setFwMustCheck(True)
|
|
except ExternalError:
|
|
raise ExternalError("Big Oops happened: situation is out of " +
|
|
"control. Something is wrong with your " +
|
|
"setup. Please check your settings")
|
|
except KeyboardInterrupt:
|
|
# When the user press <ctrl>+<c> we exit nicely.
|
|
killApp()
|