mirror of https://github.com/fail2ban/fail2ban
128 lines
3.4 KiB
Python
128 lines
3.4 KiB
Python
# emacs: -*- mode: python; py-indent-offset: 4; indent-tabs-mode: t -*-
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# vi: set ft=python sts=4 ts=4 sw=4 noet :
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# This file is part of Fail2Ban.
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#
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# Fail2Ban is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# Fail2Ban is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with Fail2Ban; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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__author__ = "Cyril Jaquier"
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__copyright__ = "Copyright (c) 2004 Cyril Jaquier"
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__license__ = "GPL"
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import re, sre_constants
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##
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# Regular expression class.
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#
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# This class represents a regular expression with its compiled version.
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class Regex:
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##
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# Constructor.
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#
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# Creates a new object. This method can throw RegexException in order to
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# avoid construction of invalid object.
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# @param value the regular expression
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def __init__(self, regex):
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self._matchCache = None
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# Perform shortcuts expansions.
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# Replace "<HOST>" with default regular expression for host.
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regex = regex.replace("<HOST>", "(?:::f{4,6}:)?(?P<host>[\w\-.^_]+)")
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if regex.lstrip() == '':
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raise RegexException("Cannot add empty regex")
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try:
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self._regexObj = re.compile(regex)
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self._regex = regex
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except sre_constants.error:
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raise RegexException("Unable to compile regular expression '%s'" %
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regex)
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##
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# Gets the regular expression.
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#
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# The effective regular expression used is returned.
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# @return the regular expression
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def getRegex(self):
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return self._regex
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##
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# Searches the regular expression.
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#
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# Sets an internal cache (match object) in order to avoid searching for
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# the pattern again. This method must be called before calling any other
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# method of this object.
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# @param value the line
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def search(self, value):
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self._matchCache = self._regexObj.search(value)
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##
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# Checks if the previous call to search() matched.
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#
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# @return True if a match was found, False otherwise
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def hasMatched(self):
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if self._matchCache:
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return True
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else:
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return False
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##
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# Exception dedicated to the class Regex.
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class RegexException(Exception):
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pass
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##
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# Regular expression class.
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#
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# This class represents a regular expression with its compiled version.
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class FailRegex(Regex):
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##
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# Constructor.
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#
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# Creates a new object. This method can throw RegexException in order to
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# avoid construction of invalid object.
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# @param value the regular expression
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def __init__(self, regex):
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# Initializes the parent.
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Regex.__init__(self, regex)
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# Check for group "host"
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if "host" not in self._regexObj.groupindex:
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raise RegexException("No 'host' group in '%s'" % self._regex)
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##
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# Returns the matched host.
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#
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# This corresponds to the pattern matched by the named group "host".
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# @return the matched host
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def getHost(self):
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host = self._matchCache.group("host")
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if host is None:
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# Gets a few information.
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s = self._matchCache.string
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r = self._matchCache.re
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raise RegexException("No 'host' found in '%s' using '%s'" % (s, r))
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return str(host)
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