# 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" from failmanager import FailManager from failticket import FailTicket from jailthread import JailThread from datedetector import DateDetector from mytime import MyTime from failregex import FailRegex, Regex, RegexException 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 == "": continue 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: continue 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() lastTimeLine = 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 timeMatch = self.dateDetector.matchTime(line) if not timeMatch: # There is no valid time in this line continue # Lets split into time part and log part of the line timeLine = timeMatch.group() # Lets leave the beginning in as well, so if there is no # anchore at the beginning of the time regexp, we don't # at least allow injection. Should be harmless otherwise logLine = line[:timeMatch.start()] + line[timeMatch.end():] lastTimeLine = timeLine for element in self.findFailure(timeLine, logLine): 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 lastTimeLine: self.__lastDate[filename] = self.dateDetector.getUnixTime(lastTimeLine) 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 given split into time and log parts. # # 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, timeLine, logLine): failList = list() # Checks if we must ignore this line. if self.ignoreLine(logLine): # The ignoreregex matched. Return. return failList # Iterates over all the regular expressions. for failRegex in self.__failRegex: failRegex.search(logLine) if failRegex.hasMatched(): # The failregex matched. date = self.dateDetector.getUnixTime(timeLine) if date == None: logSys.debug("Found a match for '" + logLine +"' but no " + "valid date/time found for '" + timeLine + "'. 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() dnsToIp = staticmethod(dnsToIp) #@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 searchIP = staticmethod(searchIP) #@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 isValidIP = staticmethod(isValidIP) #@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 textToIp = staticmethod(textToIp) #@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) cidr = staticmethod(cidr) #@staticmethod def addr2bin(string): """ Convert a string IPv4 address into an unsigned integer. """ return struct.unpack("!L", socket.inet_aton(string))[0] addr2bin = staticmethod(addr2bin) #@staticmethod def bin2addr(addr): """ Convert a numeric IPv4 address into string n.n.n.n form. """ return socket.inet_ntoa(struct.pack("!L", addr)) bin2addr = staticmethod(bin2addr)