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fail2ban/fail2ban.py

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12 KiB

#!/usr/bin/env 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
#
# $Revision$
__author__ = "Cyril Jaquier"
__version__ = "$Revision$"
__date__ = "$Date$"
__copyright__ = "Copyright (c) 2004 Cyril Jaquier"
__license__ = "GPL"
import time, sys, getopt, os, string, signal
from ConfigParser import *
# Checks if log4py is present.
try:
import log4py
except:
print "log4py is needed (see README)"
sys.exit(-1)
# Appends our own modules path
sys.path.append('/usr/lib/fail2ban')
from firewall.firewall import Firewall
from logreader.logreader import LogReader
from confreader.configreader import ConfigReader
from utils.process import *
from version import version
# Gets the instance of log4py.
logSys = log4py.Logger().get_instance()
def usage():
print "Usage: fail2ban.py [OPTIONS]"
print
print "Fail2Ban v"+version+" reads log file that contains password failure report"
print "and bans the corresponding IP address using iptables."
print
print " -b start fail2ban in background"
print " -d start fail2ban in debug mode"
print " -e <INTF> ban IP on the INTF interface"
print " -c <FILE> read configuration file FILE"
print " -p <FILE> create PID lock in FILE"
print " -h display this help message"
print " -i <IP(s)> IP(s) to ignore"
print " -k kill a currently running Fail2Ban instance"
print " -l <FILE> log message in FILE"
print " -r <VALUE> allow a max of VALUE password failure"
print " -t <TIME> ban IP for TIME seconds"
print " -v verbose. Use twice for greater effect"
print " -w <FIWA> select the firewall to use. Can be iptables,"
print " ipfwadm or ipfw"
print
print "Report bugs to <lostcontrol@users.sourceforge.net>"
sys.exit(0)
def checkForRoot():
""" Check for root user.
"""
uid = `os.getuid()`
if uid == '0':
return True
else:
return False
def sigTERMhandler(signum, frame):
""" Handles the TERM signal when in daemon mode in order to
exit properly.
"""
logSys.debug("Signal handler called with sig "+`signum`)
killApp()
def killApp():
""" Flush the ban list, remove the PID lock file and exit
nicely.
"""
logSys.warn("Restoring firewall rules...")
for element in logFwList:
element[2].flushBanList(conf["debug"])
removePID(conf["pidlock"])
logSys.info("Exiting...")
sys.exit(0)
if __name__ == "__main__":
logSys.set_formatstring("%T %L %M")
conf = dict()
conf["verbose"] = 0
conf["background"] = False
conf["debug"] = False
conf["conffile"] = "/etc/fail2ban.conf"
conf["pidlock"] = "/var/run/fail2ban.pid"
conf["logging"] = False
conf["logfile"] = "/var/log/fail2ban.log"
conf["maxretry"] = 3
conf["bantime"] = 600
conf["ignoreip"] = ''
conf["interface"] = "eth0"
conf["firewall"] = "iptables"
conf["ipfw-start-rule"] = 0
conf["polltime"] = 1
# Reads the command line options.
try:
optList, args = getopt.getopt(sys.argv[1:], 'hvbdkc:l:t:i:r:e:w:p:')
except getopt.GetoptError:
usage()
# Pre-parsing of command line options for the -c option
for opt in optList:
if opt[0] == "-c":
conf["conffile"] = opt[1]
# Config file
configParser = SafeConfigParser()
configParser.read(conf["conffile"])
# background
try:
conf["background"] = configParser.getboolean("DEFAULT", "background")
except ValueError:
logSys.warn("background option should be a boolean")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("background option not in config file")
logSys.warn("Using default value")
# debug
try:
conf["debug"] = configParser.getboolean("DEFAULT", "debug")
except ValueError:
logSys.warn("debug option should be a boolean")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("debug option not in config file")
logSys.warn("Using default value")
# logfile
try:
conf["logfile"] = configParser.get("DEFAULT", "logfile")
except ValueError:
logSys.warn("logfile option should be a string")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("logfile option not in config file")
logSys.warn("Using default value")
# pidlock
try:
conf["pidlock"] = configParser.get("DEFAULT", "pidlock")
except ValueError:
logSys.warn("pidlock option should be a string")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("pidlock option not in config file")
logSys.warn("Using default value")
# maxretry
try:
conf["maxretry"] = configParser.getint("DEFAULT", "maxretry")
except ValueError:
logSys.warn("maxretry option should be an integer")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("maxretry option not in config file")
logSys.warn("Using default value")
# bantime
try:
conf["bantime"] = configParser.getint("DEFAULT", "bantime")
except ValueError:
logSys.warn("bantime option should be an integer")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("bantime option not in config file")
logSys.warn("Using default value")
# ignoreip
try:
conf["ignoreip"] = configParser.get("DEFAULT", "ignoreip")
except ValueError:
logSys.warn("ignoreip option should be a string")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("ignoreip option not in config file")
logSys.warn("Using default value")
# interface
try:
conf["interface"] = configParser.get("DEFAULT", "interface")
except ValueError:
logSys.warn("interface option should be a string")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("interface option not in config file")
logSys.warn("Using default value")
# firewall
try:
conf["firewall"] = configParser.get("DEFAULT", "firewall")
except ValueError:
logSys.warn("firewall option should be a string")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("firewall option not in config file")
logSys.warn("Using default value")
# ipfw-start-rule
try:
conf["ipfw-start-rule"] = configParser.getint("DEFAULT",
"ipfw-start-rule")
except ValueError:
logSys.warn("ipfw-start-rule option should be an integer")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("ipfw-start-rule option not in config file")
logSys.warn("Using default value")
# polltime
try:
conf["polltime"] = configParser.getint("DEFAULT", "polltime")
except ValueError:
logSys.warn("polltime option should be an integer")
logSys.warn("Using default value")
except NoOptionError:
logSys.warn("polltime option not in config file")
logSys.warn("Using default value")
for opt in optList:
if opt[0] == "-h":
usage()
if opt[0] == "-v":
conf["verbose"] = conf["verbose"] + 1
if opt[0] == "-b":
conf["background"] = True
if opt[0] == "-d":
conf["debug"] = True
if opt[0] == "-e":
conf["interface"] = opt[1]
if opt[0] == "-l":
conf["logging"] = True
conf["logfile"] = opt[1]
if opt[0] == "-t":
try:
conf["bantime"] = int(opt[1])
except ValueError:
logSys.warn("banTime must be an integer")
logSys.warn("Using default value")
if opt[0] == "-i":
conf["ignoreip"] = opt[1]
if opt[0] == "-r":
conf["retrymax"] = int(opt[1])
if opt[0] == "-w":
conf["firewall"] = opt[1]
if opt[0] == "-p":
conf["pidlock"] = opt[1]
if opt[0] == "-k":
pid = checkForPID(conf["pidlock"])
if pid:
killPID(int(pid))
logSys.warn("Killed Fail2Ban with PID "+pid)
sys.exit(0)
else:
logSys.error("No running Fail2Ban found")
sys.exit(-1)
# Process some options
for c in conf:
if c == "verbose":
logSys.warn("Verbose level is "+`conf[c]`)
if conf[c] == 1:
logSys.set_loglevel(log4py.LOGLEVEL_VERBOSE)
elif conf[c] > 1:
logSys.set_loglevel(log4py.LOGLEVEL_DEBUG)
elif c == "debug" and conf[c]:
logSys.set_loglevel(log4py.LOGLEVEL_DEBUG)
logSys.set_formatstring(log4py.FMT_DEBUG)
elif c == "background" and conf[c]:
retCode = createDaemon()
signal.signal(signal.SIGTERM, sigTERMhandler)
logSys.set_target(conf["logfile"])
if not retCode:
logSys.error("Unable to start daemon")
sys.exit(-1)
elif c == "logging" and conf[c]:
try:
open(conf["logfile"], "a")
logSys.set_target(conf["logfile"])
except IOError:
logSys.warn("Unable to log to "+conf["logfile"])
logSys.warn("Using default output for logging")
elif c == "ignoreip":
ignoreIPList = conf[c].split(' ')
elif c == "firewall":
conf[c] = string.lower(conf[c])
if conf[c] == "ipfw":
fireWallName = "Ipfw"
elif conf[c] == "ipfwadm":
fireWallName = "Ipfwadm"
else:
fireWallName = "Iptables"
# Checks for root user. This is necessary because log files
# are owned by root and firewall needs root access.
if not checkForRoot():
logSys.error("You must be root")
if not conf["debug"]:
sys.exit(-1)
# Checks that no instance of Fail2Ban is currently running.
pid = checkForPID(conf["pidlock"])
if pid:
logSys.error("Fail2Ban already running with PID "+pid)
sys.exit(-1)
else:
createPID(conf["pidlock"])
logSys.debug("ConfFile is "+conf["conffile"])
logSys.debug("BanTime is "+`conf["bantime"]`)
logSys.debug("retryAllowed is "+`conf["maxretry"]`)
# Reads the config file and create a LogReader instance for
# each log file to check.
confReader = ConfigReader(conf["conffile"]);
confReader.openConf()
logFwList = list()
for t in confReader.getSections():
l = confReader.getLogOptions(t)
if l["enabled"]:
# Creates a logreader object
lObj = LogReader(l["logfile"], l["timeregex"], l["timepattern"],
l["failregex"], conf["bantime"])
# Creates a firewall object
fObj = Firewall(l["fwbanrule"], l["fwunbanrule"], conf["bantime"],
conf["interface"])
# Links them into a list. I'm not really happy
# with this :/
logFwList.append([t, lObj, fObj, dict()])
# We add 127.0.0.1 to the ignore list has we do not want
# to be ban ourself.
for element in logFwList:
element[1].addIgnoreIP("127.0.0.1")
while len(ignoreIPList) > 0:
ip = ignoreIPList.pop()
for element in logFwList:
element[1].addIgnoreIP(ip)
logSys.info("Fail2Ban v"+version+" is running")
# Main loop
while True:
try:
sys.stdout.flush()
sys.stderr.flush()
# Checks if some IP have to be remove from ban
# list.
for element in logFwList:
element[2].checkForUnBan(conf["debug"])
# If the log file has not been modified since the
# last time, we sleep for 1 second. This is active
# polling so not very effective.
modList = list()
for element in logFwList:
if element[1].isModified():
modList.append(element)
if len(modList) == 0:
time.sleep(conf["polltime"])
continue
# Gets the failure list from the log file. For a given IP,
# takes only the service which has the most password failures.
for element in modList:
e = element[1].getFailures()
for key in e.iterkeys():
if element[3].has_key(key):
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 - failTime:
del element[3][attempt]
elif fails[attempt][0] >= conf["maxretry"]:
logSys.info(element[0] + ": " + attempt + " has " +
`element[3][attempt][0]` +
" login failure(s). Banned.")
element[2].addBanIP(attempt, conf["debug"])
del element[3][attempt]
except KeyboardInterrupt:
# When the user press <ctrl>+<c> we exit nicely.
killApp()