fail2ban/fail2ban.py

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# 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
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# Modified by: Yaroslav Halchenko (SYSLOG, findtime)
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#
# $Revision: 1.20.2.18 $
__author__ = "Cyril Jaquier"
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__version__ = "$Revision: 1.20.2.18 $"
__date__ = "$Date: 2005/09/13 20:42:33 $"
__copyright__ = "Copyright (c) 2004 Cyril Jaquier"
__license__ = "GPL"
import time, sys, getopt, os, string, signal, logging, logging.handlers, copy
from ConfigParser import *
from version import version
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from firewall.firewall import Firewall
from logreader.logreader import LogReader
from confreader.configreader import ConfigReader
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from utils.mail import Mail
from utils.pidlock import PIDLock
from utils.dns import *
from utils.process import *
# Get the instance of the logger.
logSys = logging.getLogger("fail2ban")
# Get PID lock file instance
pidLock = PIDLock()
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# Global variables
logFwList = list()
conf = dict()
def dispUsage():
""" Prints Fail2Ban command line options and exits
"""
print "Usage: "+sys.argv[0]+" [OPTIONS]"
print
print "Fail2Ban v"+version+" reads log file that contains password failure report"
print "and bans the corresponding IP addresses using firewall rules."
print
print " -b start in background"
print " -d start in debug mode"
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 instance"
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"
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print " -V print software version"
print
print "Report bugs to <lostcontrol@users.sourceforge.net>"
sys.exit(0)
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def dispVersion():
""" Prints Fail2Ban version and exits
"""
print sys.argv[0]+" "+version
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`)
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killApp()
def initializeFwRules():
""" Initializes firewalls by running cmdstart and then
fwstart for each section
"""
# Execute global start command
executeCmd(conf["cmdstart"], conf["debug"])
# Execute start command of each section
for element in logFwList:
element[2].initialize(conf["debug"])
def reBan():
""" For each section asks the Firewall to reban known IPs
"""
for element in logFwList:
element[2].reBan(conf["debug"])
def restoreFwRules():
""" Flush the ban list
"""
logSys.warn("Restoring firewall rules...")
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for element in logFwList:
try:
element[2].flushBanList(conf["debug"])
except ExternalError:
# nothing bad really - we can survive :-)
pass
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# Execute end command of each section
for element in logFwList:
element[2].restore(conf["debug"])
# Execute global end command
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executeCmd(conf["cmdend"], conf["debug"])
def killApp():
""" Flush the ban list, remove the PID lock file and exit
nicely.
"""
# Restore Fw rules
restoreFwRules()
# Remove the PID lock
pidLock.remove()
logSys.info("Exiting...")
logging.shutdown()
sys.exit(0)
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def getCmdLineOptions(optList):
""" Gets the command line options
"""
for opt in optList:
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] == "-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["maxfailures"] = int(opt[1])
if opt[0] == "-p":
conf["pidlock"] = opt[1]
if opt[0] == "-k":
conf["kill"] = True
def main():
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""" Fail2Ban main function
"""
# Add the default logging handler
stdout = logging.StreamHandler(sys.stdout)
logSys.addHandler(stdout)
# Default formatter
formatterstring='%(levelname)s: %(message)s'
formatter = logging.Formatter('%(asctime)s ' + formatterstring)
stdout.setFormatter(formatter)
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conf["verbose"] = 0
conf["conffile"] = "/etc/fail2ban.conf"
# Reads the command line options.
try:
cmdOpts = 'hvVbdkc:t:i:r:p:'
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cmdLongOpts = ['help','version']
optList, args = getopt.getopt(sys.argv[1:], cmdOpts, cmdLongOpts)
except getopt.GetoptError:
dispUsage()
# Pre-parsing of command line options for the -c option
for opt in optList:
if opt[0] == "-c":
conf["conffile"] = opt[1]
if opt[0] in ["-h", "--help"]:
dispUsage()
if opt[0] in ["-V", "--version"]:
dispVersion()
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# Reads the config file and create a LogReader instance for
# each log file to check.
confReader = ConfigReader(conf["conffile"]);
confReader.openConf()
# Options
optionValues = (["bool", "background", False],
["str", "logtargets", "/var/log/fail2ban.log"],
["str", "syslog-target", "/dev/log"],
["int", "syslog-facility", 1],
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["bool", "debug", False],
["int", "verbose", conf["verbose"]],
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["str", "pidlock", "/var/run/fail2ban.pid"],
["int", "maxfailures", 5],
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["int", "bantime", 600],
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["int", "findtime", 600],
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["str", "ignoreip", ""],
["int", "polltime", 1],
["str", "cmdstart", ""],
["str", "cmdend", ""],
["int", "reinittime", 100],
["int", "maxreinits", 100])
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# Gets global configuration options
conf.update(confReader.getLogOptions("DEFAULT", optionValues))
# Gets command line options
getCmdLineOptions(optList)
# PID lock
pidLock.setPath(conf["pidlock"])
# Now we can kill properly a running instance if needed
try:
conf["kill"]
pid = pidLock.exists()
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)
except KeyError:
pass
# Start Fail2Ban in daemon mode
if conf["background"]:
retCode = createDaemon()
signal.signal(signal.SIGTERM, sigTERMhandler)
if not retCode:
logSys.error("Unable to start daemon")
sys.exit(-1)
# First setup Log targets
# Bug fix for #1234699
os.umask(0077)
for target in conf["logtargets"].split():
# target formatter
# By default global formatter is taken. Is different for SYSLOG
tformatter = formatter
if target == "STDERR":
hdlr = logging.StreamHandler(sys.stderr)
elif target == "SYSLOG":
# SYSLOG target can be either
# a socket (file, so it starts with /)
# or hostname
# or hostname:port
syslogtargets = re.findall("(/[\w/]*)|([^/ ][^: ]*)(:(\d+)){,1}",
conf["syslog-target"])
# we are waiting for a single match
syslogtargets = syslogtargets[0]
# assign facility if it was defined
if conf["syslog-facility"] < 0:
facility = handlers.SysLogHandler.LOG_USER
else:
facility = conf["syslog-facility"]
if len(syslogtargets) == 0: # everything default
hdlr = logging.handlers.SysLogHandler()
else:
if not ( syslogtargets[0] == "" ): # got socket
syslogtarget = syslogtargets[0]
else: # got hostname and maybe a port
if syslogtargets[3] == "": # no port specified
port = 514
else:
port = int(syslogtargets[3])
syslogtarget = (syslogtargets[1], port)
hdlr = logging.handlers.SysLogHandler(syslogtarget, facility)
tformatter = logging.Formatter("fail2ban[%(process)d]: " +
formatterstring);
else:
# Target should be a file
try:
open(target, "a")
hdlr = logging.FileHandler(target)
except IOError:
logSys.error("Unable to log to " + target)
continue
# Set formatter and add handler to logger
hdlr.setFormatter(tformatter)
logSys.addHandler(hdlr)
# Process some options
# Verbose level
if conf["verbose"]:
logSys.warn("Verbose level is "+`conf["verbose"]`)
if conf["verbose"] == 1:
logSys.setLevel(logging.INFO)
elif conf["verbose"] > 1:
logSys.setLevel(logging.DEBUG)
# Set debug log level
if conf["debug"]:
logSys.setLevel(logging.DEBUG)
formatterstring = ('%(levelname)s: [%(filename)s (%(lineno)d)] ' +
'%(message)s')
formatter = logging.Formatter("%(asctime)s " + formatterstring)
stdout.setFormatter(formatter)
logSys.warn("DEBUG MODE: FIREWALL COMMANDS ARE _NOT_ EXECUTED BUT " +
"ONLY DISPLAYED IN THE LOG MESSAGES")
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# Ignores IP list
ignoreIPList = conf["ignoreip"].split(' ')
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# 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 = pidLock.exists()
if pid:
logSys.error("Fail2Ban already running with PID "+pid)
sys.exit(-1)
else:
ret = pidLock.create()
if not ret:
# Unable to create PID lock. Exit
sys.exit(-1)
logSys.debug("ConfFile is " + conf["conffile"])
logSys.debug("BanTime is " + `conf["bantime"]`)
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logSys.debug("FindTime is " + `conf["findtime"]`)
logSys.debug("MaxFailure is " + `conf["maxfailures"]`)
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# Options
optionValues = (["bool", "enabled", False],
["str", "host", "localhost"],
["int", "port", "25"],
["str", "from", "root"],
["str", "to", "root"],
["str", "subject", "[Fail2Ban] Banned <ip>"],
["str", "message", "Fail2Ban notification"])
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# Gets global configuration options
mailConf = confReader.getLogOptions("MAIL", optionValues)
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# Create mailer if enabled
if mailConf["enabled"]:
logSys.debug("Mail enabled")
mail = Mail(mailConf["host"], mailConf["port"])
mail.setFromAddr(mailConf["from"])
mail.setToAddr(mailConf["to"])
logSys.debug("to: " + mailConf["to"] + " from: " + mailConf["from"])
# Options
optionValues = (["bool", "enabled", False],
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["str", "logfile", "/dev/null"],
["int", "maxfailures", conf["maxfailures"]],
["int", "bantime", conf["bantime"]],
["int", "findtime", conf["findtime"]],
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["str", "timeregex", ""],
["str", "timepattern", ""],
["str", "failregex", ""],
["str", "fwstart", ""],
["str", "fwend", ""],
["str", "fwban", ""],
["str", "fwunban", ""],
["str", "fwcheck", ""])
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logSys.info("Fail2Ban v" + version + " is running")
enabledSections = []
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# Gets the options of each sections
for t in confReader.getSections():
l = confReader.getLogOptions(t, optionValues)
if l["enabled"]:
# Creates a logreader object
enabledSections.append(t)
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lObj = LogReader(l["logfile"], l["timeregex"], l["timepattern"],
l["failregex"], l["maxfailures"], l["findtime"])
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# Creates a firewall object
fObj = Firewall(l["fwban"], l["fwunban"], l["fwcheck"], l["bantime"])
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# Links them into a list. I'm not really happy
# with this :/
logFwList.append([t, lObj, fObj, dict()])
logSys.info("Enabled sections: %s"%enabledSections)
# We add 127.0.0.1 to the ignore list has we do not want
# to be ban ourself.
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for element in logFwList:
element[1].addIgnoreIP("127.0.0.1")
while len(ignoreIPList) > 0:
ip = ignoreIPList.pop()
# Bug fix for #1239557
if isValidIP(ip):
for element in logFwList:
element[1].addIgnoreIP(ip)
else:
logSys.warn(ip + " is not a valid IP address")
initializeFwRules()
# try to reinit once if it fails immediately
lastReinitTime = time.time() - conf["reinittime"] - 1
reinits = 0
# Main loop
while True:
try:
sys.stdout.flush()
sys.stderr.flush()
# Checks if some IP have to be remove from ban
# list.
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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()
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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:
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e = element[1].getFailures()
for key in e.iterkeys():
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if element[3].has_key(key):
element[3][key] = (element[3][key][0] + e[key][0],
e[key][1])
else:
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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.
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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():
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aInfo = {"section": element[0],
"ip": attempt,
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"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()
# 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()
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()