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fail2ban
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Code Issues Releases Wiki Activity

remade handling of missing chains or other errors from IPTables

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debian-releases/etch
Yaroslav Halchenko 19 years ago
parent 03e7d722de
commit da0bb74180
3 changed files with 174 additions and 146 deletions
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37
fail2ban
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@ -26,7 +26,7 @@ __date__ = "$Date: 2005/08/04 20:51:14 $"
__copyright__ = "Copyright (c) 2004 Cyril Jaquier"
__license__ = "GPL"
import sys, traceback, logging, time
import sys, traceback, logging
# Appends our own modules path.
sys.path.append("/usr/share/fail2ban")
@ -34,16 +34,6 @@ sys.path.append("/usr/share/fail2ban")
# Now we can import our modules.
import fail2ban
from utils.pidlock import PIDLock
from utils.process import ExternalError
# Start the application. Handle all the unhandled exceptions
# yoh: I don't think that this parameters need to be configured
# and probably maxRestarts should be removed
legitRestartTime = 10 # legitimate minimal restart time
maxRestarts = 100 # max number of times to perform restart
lastRestartTime = time.time()
restarts = 0
# Get the instance of the logger.
logSys = logging.getLogger("fail2ban")
@ -51,21 +41,9 @@ logSys = logging.getLogger("fail2ban")
# Get PID lock file instance
pidLock = PIDLock()
# Start the application. Handle all the unhandled exceptions
try:
while True:
restarts += 1
try:
fail2ban.main(restarts>1)
except ExternalError, e:
# There went something wrong while dealing with Iptables. May be chain got
# removed?
logSys.error("Fail2Ban got a problem: " + e.__str__())
if (time.time() - lastRestartTime > legitRestartTime) and (restarts < maxRestarts):
logSys.error("Restarting for the %d time "%restarts)
lastRestartTime = time.time()
else:
logSys.error("Exiting: restarts follow too often, or too many restart attempts")
sys.exit(0)
fail2ban.main()
except SystemExit:
# We called sys.exit(). Nothing wrong so just pass
pass
@ -77,9 +55,6 @@ except Exception, e:
logSys.error("Type: " + `type.__name__` + "\n" +
"Value: " + `e.args` + "\n" +
"TB: " + `tbStack`)
# Remove the PID lock file. Should close #1239562
pidLock.remove()
logSys.info("Exiting...")
logging.shutdown()
# Remove the PID lock file. Should close #1239562
pidLock.remove()
logging.shutdown()

267
fail2ban.py
Unescape View File

@ -25,7 +25,7 @@ __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
import time, sys, getopt, os, string, signal, logging, logging.handlers, copy
from ConfigParser import *
from version import version
@ -92,12 +92,34 @@ def sigTERMhandler(signum, frame):
logSys.debug("Signal handler called with sig "+`signum`)
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:
l = element[4]
executeCmd(l["fwstart"], 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...")
for element in logFwList:
element[2].flushBanList(conf["debug"])
try:
element[2].flushBanList(conf["debug"])
except ExternalError, e:
# nothing bad really - we can survive :-)
pass
# Execute end command of each section
for element in logFwList:
l = element[4]
@ -106,11 +128,15 @@ def restoreFwRules():
executeCmd(conf["cmdend"], conf["debug"])
def killApp():
""" Flush the ban list, remove and exit
""" 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)
def getCmdLineOptions(optList):
@ -138,12 +164,9 @@ def getCmdLineOptions(optList):
if opt[0] == "-k":
conf["kill"] = True
def main(secondaryStart):
def main():
""" Fail2Ban main function
"""
# (re)Initialize global variables
logFwList.__init__()
conf.clear()
# Add the default logging handler
stdout = logging.StreamHandler(sys.stdout)
@ -218,110 +241,106 @@ def main(secondaryStart):
except KeyError:
pass
# If it is not a hot restart
# fork, setup logging, create pid, check for root
if not secondaryStart:
# Start Fail2Ban in daemon mode
if conf["background"]:
logSys.debug("Daemonizing")
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")
# 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)
# 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:
ret = pidLock.create()
if not ret:
# Unable to create PID lock. Exit
sys.exit(-1)
# 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")
# Ignores IP list
ignoreIPList = conf["ignoreip"].split(' ')
# 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"]`)
logSys.debug("FindTime is " + `conf["findtime"]`)
@ -394,12 +413,15 @@ def main(secondaryStart):
else:
logSys.warn(ip + " is not a valid IP address")
# Execute global start command
executeCmd(conf["cmdstart"], conf["debug"])
# Execute start command of each section
for element in logFwList:
l = element[4]
executeCmd(l["fwstart"], conf["debug"])
initializeFwRules()
# yoh: I don't think that this parameters need to be configured
# and probably maxRestarts should be removed
legitRestartTime = 10 # legitimate minimal restart time
maxRestarts = 100 # max number of times to perform restart
lastRestartTime = time.time()
restarts = 0
# Main loop
while True:
try:
@ -459,10 +481,27 @@ def main(secondaryStart):
mail.sendmail(mailConf["subject"],
mailConf["message"], aInfo)
del element[3][attempt]
except ExternalError:
# restore as much as possible before restart
except ExternalError, e:
# Something wrong while dealing with Iptables.
# May be chain got removed?
logSys.error("Fail2Ban got a problem: " + e.__str__())
if (unixTime - lastRestartTime > legitRestartTime) and (restarts < maxRestarts):
logSys.error("Reinitializing firewalls for the %dst time "%restarts)
lastRestartTime = time.time()
else:
logSys.error("Exiting: restarts follow too often, or too many restart attempts")
killApp()
# save firewalls to keep a list of IPs for rebanning
logFwListCopy = copy.deepcopy(logFwList)
# restore as much as possible
restoreFwRules()
raise
# reinitialize all the chains
initializeFwRules()
# restore the lists of baned IPs
logFwList = logFwListCopy
# reBan known IPs
reBan()
except KeyboardInterrupt:
# When the user press <ctrl>+<c> we exit nicely.
killApp()

16
firewall/firewall.py
Unescape View File

@ -72,6 +72,20 @@ class Firewall:
executeCmd(self.unBanIP(aInfo), debug)
else:
logSys.error(ip+" not in ban list")
def reBan(self, debug):
""" Re-Bans known IPs.
"""
for ip in self.banList:
aInfo = {"ip": ip,
"bantime":self.banList[ip]}
logSys.warn("ReBan "+ip)
# next piece is similar to the on in addBanIp
# so might be one more function will not hurt
self.runCheck("pre-fw-reban", debug)
cmd = self.banIP(aInfo)
if executeCmd(cmd, debug):
raise ExternalError("Firewall: execution of fwban command '%s' failed"%cmd)
def inBanList(self, ip):
""" Checks if IP is in ban list.
@ -106,7 +120,7 @@ class Firewall:
"bantime": element[1],
"unbantime": time.time()}
self.delBanIP(aInfo, debug)
def banIP(self, aInfo):
""" Returns query to ban IP.
"""

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