fail2ban-regex

#!/usr/bin/python
# emacs: -*- mode: python; py-indent-offset: 4; indent-tabs-mode: t -*-
# vi: set ft=python sts=4 ts=4 sw=4 noet :
#
# 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
"""
Fail2Ban  reads log file that contains password failure report
and bans the corresponding IP addresses using firewall rules.

This tools can test regular expressions for "fail2ban".

"""

__author__ = "Cyril Jaquier, Yaroslav Halchenko"
__copyright__ = "Copyright (c) 2004-2008 Cyril Jaquier, 2012-2013 Yaroslav Halchenko"
__license__ = "GPL"

import getopt, sys, time, logging, os, urllib

# Inserts our own modules path first in the list
# fix for bug #343821
try:
	from common.version import version
except ImportError, e:
	sys.path.insert(1, "/usr/share/fail2ban")
	from common.version import version

from optparse import OptionParser, Option

from client.configparserinc import SafeConfigParserWithIncludes
from ConfigParser import NoOptionError, NoSectionError, MissingSectionHeaderError
from server.filter import Filter
from server.failregex import RegexException

from testcases.utils import FormatterWithTraceBack
# Gets the instance of the logger.
logSys = logging.getLogger("fail2ban")

def debuggexURL(sample, regex):
	q = urllib.urlencode({ 're': regex.replace('<HOST>', '(?&.ipv4)'),
							'str': sample,
							'flavor': 'python' })
	return 'http://www.debuggex.com/?' + q

def shortstr(s, l=53):
	"""Return shortened string
	"""
	if len(s) > l:
		return s[:l-3] + '...'
	return s

def pprint_list(l, header=None):
	if not len(l):
		return
	if header:
		s = "|- %s\n" % header
	else:
		s = ''
	print s + "|  " + "\n|  ".join(l) + '\n`-'


def get_opt_parser():
	# use module docstring for help output
	p = OptionParser(
				usage="%s [OPTIONS] <LOG> <REGEX> [IGNOREREGEX]\n" % sys.argv[0] + __doc__
				+ """
LOG:
    string                  a string representing a log line
    filename                path to a log file (/var/log/auth.log)

REGEX:
    string                  a string representing a 'failregex'
    filename                path to a filter file (filter.d/sshd.conf)

IGNOREREGEX:
    string                  a string representing an 'ignoreregex'
    filename                path to a filter file (filter.d/sshd.conf)

Copyright (c) 2004-2008 Cyril Jaquier, 2008- Fail2Ban Contributors
Copyright of modifications held by their respective authors.
Licensed under the GNU General Public License v2 (GPL).

Written by Cyril Jaquier <cyril.jaquier@fail2ban.org>.
Many contributions by Yaroslav O. Halchenko and Steven Hiscocks.

Report bugs to https://github.com/fail2ban/fail2ban/issues
""",
				version="%prog " + version)

	p.add_options([
		Option('-l', "--log-level", type="choice",
			   dest="log_level",
			   choices=('heavydebug', 'debug', 'info', 'warning', 'error', 'fatal'),
			   default=None,
			   help="Log level for the Fail2Ban logger to use"),
		Option("-v", "--verbose", action='store_true',
			   help="Be verbose in output"),
		Option("-D", "--debuggex", action='store_true',
			   help="Produce debuggex.com urls for debugging there"),
		Option("--print-all-missed", action='store_true',
			   help="Either to print all missed lines"),
		Option("--print-all-ignored", action='store_true',
			   help="Either to print all ignored lines"),
		Option("-t", "--log-traceback", action='store_true',
			   help="Enrich log-messages with compressed tracebacks"),
		Option("--full-traceback", action='store_true',
			   help="Either to make the tracebacks full, not compressed (as by default)"),
		])

	return p


class RegexStat(object):

	def __init__(self, failregex):
		self._stats = 0
		self._failregex = failregex
		self._ipList = list()

	def __str__(self):
		return "%s(%r) %d failed: %s" \
		  % (self.__class__, self._failregex, self._stats, self._ipList)

	def inc(self):
		self._stats += 1

	def getStats(self):
		return self._stats

	def getFailRegex(self):
		return self._failregex

	def appendIP(self, value):
		self._ipList.append(value)

	def getIPList(self):
		return self._ipList


class LineStats(object):
	"""Just a convenience container for stats
	"""
	def __init__(self):
		self.tested = self.matched = 0
		self.missed_lines = []
		self.missed_lines_timeextracted = []
		self.ignored_lines = []
		self.ignored_lines_timeextracted = []

	def __str__(self):
		return "%(tested)d lines, %(ignored)d ignored, %(matched)d matched, %(missed)d missed" % self

	@property
	def ignored(self):
		return len(self.ignored_lines)

	@property
	def missed(self):
		return self.tested - (self.ignored + self.matched)

	# just for convenient str
	def __getitem__(self, key):
		return getattr(self, key)


class Fail2banRegex(object):

	CONFIG_DEFAULTS = {'configpath' : "/etc/fail2ban/"}

	def __init__(self, opts):
		self._verbose = opts.verbose
		self._debuggex = opts.debuggex
		self._print_all_missed = opts.print_all_missed
		self._print_all_ignored = opts.print_all_ignored

		self._filter = Filter(None)
		self._ignoreregex = list()
		self._failregex = list()
		self._line_stats = LineStats()


	def readRegex(self, value, regextype):
		assert(regextype in ('fail', 'ignore'))
		regex = regextype + 'regex'
		if os.path.isfile(value):
			reader = SafeConfigParserWithIncludes(defaults=self.CONFIG_DEFAULTS)
			try:
				reader.read(value)
				print "Use %11s file : %s" % (regex, value)
				# TODO: reuse functionality in client
				regex_values = [
					RegexStat(m)
					for m in reader.get("Definition", regex).split('\n')
					if m != ""]
			except NoSectionError:
				print "No [Definition] section in %s" % value
				return False
			except NoOptionError:
				print "No %s option in %s" % (regex, value)
				return False
			except MissingSectionHeaderError:
				print "No section headers in %s" % value
				return False
		else:
			print "Use %11s line : %s" % (regex, shortstr(value))
			regex_values = [RegexStat(value)]

		setattr(self, "_" + regex, regex_values)
		for regex in regex_values:
			getattr(
				self._filter,
				'add%sRegex' % regextype.title())(regex.getFailRegex())
		return True

	def testIgnoreRegex(self, line):
		found = False
		try:
			ret = self._filter.ignoreLine(line)
			if ret is not None:
				found = True
				regex = self._ignoreregex[ret].inc()
		except RegexException, e:
			print e
			return False
		return found

	def testRegex(self, line):
		try:
			line, ret = self._filter.processLine(line, checkAllRegex=True)
			for match in ret:
				# Append True/False flag depending if line was matched by
				# more than one regex
				match.append(len(ret)>1)
				regex = self._failregex[match[0]]
				regex.inc()
				regex.appendIP(match)
		except RegexException, e:
			print e
			return False
		except IndexError:
			print "Sorry, but no <HOST> found in regex"
			return False
		return line, ret


	def process(self, test_lines):

		for line_no, line in enumerate(test_lines):
			if line.startswith('#') or not line.strip():
				# skip comment and empty lines
				continue
			is_ignored = fail2banRegex.testIgnoreRegex(line)
			line_datetimestripped, ret = fail2banRegex.testRegex(line)

			if is_ignored:
				self._line_stats.ignored_lines.append(line)
				self._line_stats.ignored_lines_timeextracted.append(line_datetimestripped)

			if len(ret) > 0:
				assert(not is_ignored)
				self._line_stats.matched += 1
			else:
				if not is_ignored:
					self._line_stats.missed_lines.append(line)
					self._line_stats.missed_lines_timeextracted.append(line_datetimestripped)
			self._line_stats.tested += 1

			if line_no % 10 == 0:
				self._filter.dateDetector.sortTemplate()



	def printLines(self, ltype):
		lstats = self._line_stats
		assert(len(lstats.missed_lines) == lstats.tested - (lstats.matched + lstats.ignored))
		l = lstats[ltype + '_lines']
		if len(l):
			header = "%s line(s):" % (ltype.capitalize(),)
			if self._debuggex:
				if ltype == 'missed':
					regexlist = self._failregex
				else:
					regexlist = self._ignoreregex
				l = lstats[ltype + '_lines_timeextracted']
				lines = len(l)*len(regexlist)
				if lines < 20 or getattr(self, '_print_all_' + ltype):
					ans = [[]]
					for arg in [l, regexlist]:
					    ans = [ x + [y] for x in ans for y in arg ]
					b = map(lambda a: a[0] +  ' | ' + a[1].getFailRegex() + ' |  ' + debuggexURL(a[0], a[1].getFailRegex()), ans)
					pprint_list([x.rstrip() for x in b], header)
				else:
					print "%s: too many to print.  Use --print-all-%s " \
						  "to print all %d lines" % (header, ltype, lines)
			elif len(l) < 20 or getattr(self, '_print_all_' + ltype):
				pprint_list([x.rstrip() for x in l], header)
			else:
				print "%s: too many to print.  Use --print-all-%s " \
					  "to print all %d lines" % (header, ltype, len(l))

	def printStats(self):
		print
		print "Results"
		print "======="

		def print_failregexes(title, failregexes):
			# Print title
			total, out = 0, []
			for cnt, failregex in enumerate(failregexes):
				match = failregex.getStats()
				total += match
				if (match or self._verbose):
					out.append("%2d) [%d] %s" % (cnt+1, match, failregex.getFailRegex()))

				if self._verbose and len(failregex.getIPList()):
					for ip in failregex.getIPList():
						timeTuple = time.localtime(ip[2])
						timeString = time.strftime("%a %b %d %H:%M:%S %Y", timeTuple)
						out.append(
							"    %s  %s%s" % (
								ip[1],
								timeString,
								ip[3] and " (multiple regex matched)" or ""))

			print "\n%s: %d total" % (title, total)
			pprint_list(out, " #) [# of hits] regular expression")
			return total

		# Print title
		total = print_failregexes("Failregex", self._failregex)
		_ = print_failregexes("Ignoreregex", self._ignoreregex)


		print "\nDate template hits:"
		out = []
		for template in self._filter.dateDetector.getTemplates():
			if self._verbose or template.getHits():
				out.append("[%d] %s" % (template.getHits(), template.getName()))
		pprint_list(out, "[# of hits] date format")

		print "\nLines: %s" % self._line_stats

		self.printLines('ignored')
		self.printLines('missed')

		return True


if __name__ == "__main__":

	parser = get_opt_parser()
	(opts, args) = parser.parse_args()

	fail2banRegex = Fail2banRegex(opts)

	# We need 2 or 3 parameters
	if not len(args) in (2, 3):
		sys.stderr.write("ERROR: provide both <LOG> and <REGEX>.\n\n")
		parser.print_help()
		sys.exit(-1)

	# TODO: taken from -testcases -- move common functionality somewhere
	if opts.log_level is not None: # pragma: no cover
		# so we had explicit settings
		logSys.setLevel(getattr(logging, opts.log_level.upper()))
	else: # pragma: no cover
		# suppress the logging but it would leave unittests' progress dots
		# ticking, unless like with '-l fatal' which would be silent
		# unless error occurs
		logSys.setLevel(getattr(logging, 'FATAL'))

	# Add the default logging handler
	stdout = logging.StreamHandler(sys.stdout)

	fmt = 'D: %(message)s'

	if opts.log_traceback:
		Formatter = FormatterWithTraceBack
		fmt = (opts.full_traceback and ' %(tb)s' or ' %(tbc)s') + fmt
	else:
		Formatter = logging.Formatter

	# Custom log format for the verbose tests runs
	if opts.verbose > 1: # pragma: no cover
		stdout.setFormatter(Formatter(' %(asctime)-15s %(thread)s' + fmt))
	else: # pragma: no cover
		# just prefix with the space
		stdout.setFormatter(Formatter(fmt))
	logSys.addHandler(stdout)

	print
	print "Running tests"
	print "============="
	print

	cmd_log, cmd_regex = args[:2]

	if len(args) == 3:
		fail2banRegex.readRegex(args[2], 'ignore') or sys.exit(-1)

	fail2banRegex.readRegex(cmd_regex, 'fail') or sys.exit(-1)

	if os.path.isfile(cmd_log):
		try:
			hdlr = open(cmd_log)
			print "Use         log file : %s" % cmd_log
			test_lines = hdlr # Iterable
		except IOError, e:
			print e
			sys.exit(-1)
	else:
		print "Use      single line : %s" % shortstr(cmd_log)
		test_lines = [ cmd_log ]
	print

	fail2banRegex.process(test_lines)

	fail2banRegex.printStats() or sys.exit(-1)