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# 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.
__author__ = "Fail2Ban Developers, Alexander Koeppe, Serg G. Brester, Yaroslav Halchenko"
__copyright__ = "Copyright (c) 2004-2016 Fail2ban Developers"
__license__ = "GPL"
import socket
import struct
import re
from .utils import Utils
from ..helpers import getLogger
# Gets the instance of the logger.
logSys = getLogger(__name__)
##
# Helper functions
#
#
def asip(ip):
"""A little helper to guarantee ip being an IPAddr instance"""
if isinstance(ip, IPAddr):
return ip
return IPAddr(ip)
def getfqdn(name=''):
"""Get fully-qualified hostname of given host, thereby resolve of an external
IPs and name will be preferred before the local domain (or a loopback), see gh-2438
"""
try:
name = name or socket.gethostname()
names = (
ai[3] for ai in socket.getaddrinfo(
name, None, 0, socket.SOCK_DGRAM, 0, socket.AI_CANONNAME
) if ai[3]
)
if names:
# first try to find a fqdn starting with the host name like www.domain.tld for www:
pref = name+'.'
first = None
for ai in names:
if ai.startswith(pref):
return ai
if not first: first = ai
# not found - simply use first known fqdn:
return first
except socket.error:
pass
# fallback to python's own getfqdn routine:
return socket.getfqdn(name)
##
# Utils class for DNS handling.
#
# This class contains only static methods used to handle DNS
#
class DNSUtils:
# todo: make configurable the expired time and max count of cache entries:
CACHE_nameToIp = Utils.Cache(maxCount=1000, maxTime=5*60)
CACHE_ipToName = Utils.Cache(maxCount=1000, maxTime=5*60)
@staticmethod
def dnsToIp(dns):
""" Convert a DNS into an IP address using the Python socket module.
Thanks to Kevin Drapel.
"""
# cache, also prevent long wait during retrieving of ip for wrong dns or lazy dns-system:
ips = DNSUtils.CACHE_nameToIp.get(dns)
if ips is not None:
return ips
# retrieve ips
ips = set()
saveerr = None
for fam, ipfam in ((socket.AF_INET, IPAddr.FAM_IPv4), (socket.AF_INET6, IPAddr.FAM_IPv6)):
try:
for result in socket.getaddrinfo(dns, None, fam, 0, socket.IPPROTO_TCP):
# if getaddrinfo returns something unexpected:
if len(result) < 4 or not len(result[4]): continue
# get ip from `(2, 1, 6, '', ('127.0.0.1', 0))`,be sure we've an ip-string
# (some python-versions resp. host configurations causes returning of integer there):
ip = IPAddr(str(result[4][0]), ipfam)
if ip.isValid:
ips.add(ip)
except Exception as e:
saveerr = e
if not ips and saveerr:
logSys.warning("Unable to find a corresponding IP address for %s: %s", dns, saveerr)
DNSUtils.CACHE_nameToIp.set(dns, ips)
return ips
@staticmethod
def ipToName(ip):
# cache, also prevent long wait during retrieving of name for wrong addresses, lazy dns:
v = DNSUtils.CACHE_ipToName.get(ip, ())
if v != ():
return v
# retrieve name
try:
v = socket.gethostbyaddr(ip)[0]
except socket.error as e:
logSys.debug("Unable to find a name for the IP %s: %s", ip, e)
v = None
DNSUtils.CACHE_ipToName.set(ip, v)
return v
@staticmethod
def textToIp(text, useDns):
""" Return the IP of DNS found in a given text.
"""
ipList = set()
# Search for plain IP
plainIP = IPAddr.searchIP(text)
if plainIP is not None:
ip = IPAddr(plainIP)
if ip.isValid:
ipList.add(ip)
# If we are allowed to resolve -- give it a try if nothing was found
if useDns in ("yes", "warn") and not ipList:
# Try to get IP from possible DNS
ip = DNSUtils.dnsToIp(text)
ipList.update(ip)
if ip and useDns == "warn":
logSys.warning("Determined IP using DNS Lookup: %s = %s",
text, ipList)
return ipList
@staticmethod
def getHostname(fqdn=True):
"""Get short hostname or fully-qualified hostname of host self"""
# try find cached own hostnames (this tuple-key cannot be used elsewhere):
key = ('self','hostname', fqdn)
name = DNSUtils.CACHE_ipToName.get(key)
# get it using different ways (hostname, fully-qualified or vice versa):
if name is None:
name = ''
for hostname in (
(getfqdn, socket.gethostname) if fqdn else (socket.gethostname, getfqdn)
):
try:
name = hostname()
break
except Exception as e: # pragma: no cover
logSys.warning("Retrieving own hostnames failed: %s", e)
# cache and return :
DNSUtils.CACHE_ipToName.set(key, name)
return name
@staticmethod
def getSelfNames():
"""Get own host names of self"""
# try find cached own hostnames (this tuple-key cannot be used elsewhere):
key = ('self','dns')
names = DNSUtils.CACHE_ipToName.get(key)
# get it using different ways (a set with names of localhost, hostname, fully qualified):
if names is None:
names = set([
'localhost', DNSUtils.getHostname(False), DNSUtils.getHostname(True)
]) - set(['']) # getHostname can return ''
# cache and return :
DNSUtils.CACHE_ipToName.set(key, names)
return names
@staticmethod
def getSelfIPs():
"""Get own IP addresses of self"""
# try find cached own IPs (this tuple-key cannot be used elsewhere):
key = ('self','ips')
ips = DNSUtils.CACHE_nameToIp.get(key)
# get it using different ways (a set with IPs of localhost, hostname, fully qualified):
if ips is None:
ips = set()
for hostname in DNSUtils.getSelfNames():
try:
ips |= set(DNSUtils.textToIp(hostname, 'yes'))
except Exception as e: # pragma: no cover
logSys.warning("Retrieving own IPs of %s failed: %s", hostname, e)
# cache and return :
DNSUtils.CACHE_nameToIp.set(key, ips)
return ips
@staticmethod
def IPv6IsAllowed():
# return os.path.exists("/proc/net/if_inet6") || any((':' in ip) for ip in DNSUtils.getSelfIPs())
return any((':' in ip.ntoa) for ip in DNSUtils.getSelfIPs())
##
# Class for IP address handling.
#
# This class contains methods for handling IPv4 and IPv6 addresses.
#
class IPAddr(object):
"""Encapsulate functionality for IPv4 and IPv6 addresses
"""
IP_4_RE = r"""(?:\d{1,3}\.){3}\d{1,3}"""
IP_6_RE = r"""(?:[0-9a-fA-F]{1,4}::?|::){1,7}(?:[0-9a-fA-F]{1,4}|(?<=:):)"""
IP_4_6_CRE = re.compile(
r"""^(?:(?P<IPv4>%s)|\[?(?P<IPv6>%s)\]?)$""" % (IP_4_RE, IP_6_RE))
# An IPv4 compatible IPv6 to be reused (see below)
IP6_4COMPAT = None
# object attributes
__slots__ = '_family','_addr','_plen','_maskplen','_raw'
# todo: make configurable the expired time and max count of cache entries:
CACHE_OBJ = Utils.Cache(maxCount=10000, maxTime=5*60)
CIDR_RAW = -2
CIDR_UNSPEC = -1
FAM_IPv4 = CIDR_RAW - socket.AF_INET
FAM_IPv6 = CIDR_RAW - socket.AF_INET6
def __new__(cls, ipstr, cidr=CIDR_UNSPEC):
if cidr == IPAddr.CIDR_RAW: # don't cache raw
ip = super(IPAddr, cls).__new__(cls)
ip.__init(ipstr, cidr)
return ip
# check already cached as IPAddr
args = (ipstr, cidr)
ip = IPAddr.CACHE_OBJ.get(args)
if ip is not None:
return ip
# wrap mask to cidr (correct plen):
if cidr == IPAddr.CIDR_UNSPEC:
ipstr, cidr = IPAddr.__wrap_ipstr(ipstr)
args = (ipstr, cidr)
# check cache again:
if cidr != IPAddr.CIDR_UNSPEC:
ip = IPAddr.CACHE_OBJ.get(args)
if ip is not None:
return ip
ip = super(IPAddr, cls).__new__(cls)
ip.__init(ipstr, cidr)
if ip._family != IPAddr.CIDR_RAW:
IPAddr.CACHE_OBJ.set(args, ip)
return ip
@staticmethod
def __wrap_ipstr(ipstr):
# because of standard spelling of IPv6 (with port) enclosed in brackets ([ipv6]:port),
# remove they now (be sure the <HOST> inside failregex uses this for IPv6 (has \[?...\]?)
if len(ipstr) > 2 and ipstr[0] == '[' and ipstr[-1] == ']':
ipstr = ipstr[1:-1]
# test mask:
if "/" not in ipstr:
return ipstr, IPAddr.CIDR_UNSPEC
s = ipstr.split('/', 1)
# IP address without CIDR mask
if len(s) > 2:
raise ValueError("invalid ipstr %r, too many plen representation" % (ipstr,))
if "." in s[1] or ":" in s[1]: # 255.255.255.0 resp. ffff:: style mask
s[1] = IPAddr.masktoplen(s[1])
s[1] = int(s[1])
return s
def __init(self, ipstr, cidr=CIDR_UNSPEC):
""" initialize IP object by converting IP address string
to binary to integer
"""
self._family = socket.AF_UNSPEC
self._addr = 0
self._plen = 0
self._maskplen = None
# always save raw value (normally used if really raw or not valid only):
self._raw = ipstr
# if not raw - recognize family, set addr, etc.:
if cidr != IPAddr.CIDR_RAW:
if cidr is not None and cidr < IPAddr.CIDR_RAW:
family = [IPAddr.CIDR_RAW - cidr]
else:
family = [socket.AF_INET, socket.AF_INET6]
for family in family:
try:
binary = socket.inet_pton(family, ipstr)
self._family = family
break
except socket.error:
continue
if self._family == socket.AF_INET:
# convert host to network byte order
self._addr, = struct.unpack("!L", binary)
self._plen = 32
# mask out host portion if prefix length is supplied
if cidr is not None and cidr >= 0:
mask = ~(0xFFFFFFFF >> cidr)
self._addr &= mask
self._plen = cidr
elif self._family == socket.AF_INET6:
# convert host to network byte order
hi, lo = struct.unpack("!QQ", binary)
self._addr = (hi << 64) | lo
self._plen = 128
# mask out host portion if prefix length is supplied
if cidr is not None and cidr >= 0:
mask = ~(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF >> cidr)
self._addr &= mask
self._plen = cidr
# if IPv6 address is a IPv4-compatible, make instance a IPv4
elif self.isInNet(IPAddr.IP6_4COMPAT):
self._addr = lo & 0xFFFFFFFF
self._family = socket.AF_INET
self._plen = 32
else:
self._family = IPAddr.CIDR_RAW
def __repr__(self):
return repr(self.ntoa)
def __str__(self):
return self.ntoa if isinstance(self.ntoa, str) else str(self.ntoa)
def __reduce__(self):
"""IPAddr pickle-handler, that simply wraps IPAddr to the str
Returns a string as instance to be pickled, because fail2ban-client can't
unserialize IPAddr objects
"""
return (str, (self.ntoa,))
@property
def addr(self):
return self._addr
@property
def family(self):
return self._family
FAM2STR = {socket.AF_INET: 'inet4', socket.AF_INET6: 'inet6'}
@property
def familyStr(self):
return IPAddr.FAM2STR.get(self._family)
@property
def plen(self):
return self._plen
@property
def raw(self):
"""The raw address
Should only be set to a non-empty string if prior address
conversion wasn't possible
"""
return self._raw
@property
def isValid(self):
"""Either the object corresponds to a valid IP address
"""
return self._family != socket.AF_UNSPEC
@property
def isSingle(self):
"""Returns whether the object is a single IP address (not DNS and subnet)
"""
return self._plen == {socket.AF_INET: 32, socket.AF_INET6: 128}.get(self._family, -1000)
def __eq__(self, other):
if self._family == IPAddr.CIDR_RAW and not isinstance(other, IPAddr):
return self._raw == other
if not isinstance(other, IPAddr):
if other is None: return False
other = IPAddr(other)
if self._family != other._family: return False
if self._family == socket.AF_UNSPEC:
return self._raw == other._raw
return (
(self._addr == other._addr) and
(self._plen == other._plen)
)
def __ne__(self, other):
return not (self == other)
def __lt__(self, other):
if self._family == IPAddr.CIDR_RAW and not isinstance(other, IPAddr):
return self._raw < other
if not isinstance(other, IPAddr):
if other is None: return False
other = IPAddr(other)
return self._family < other._family or self._addr < other._addr
def __add__(self, other):
if not isinstance(other, IPAddr):
other = IPAddr(other)
return "%s%s" % (self, other)
def __radd__(self, other):
if not isinstance(other, IPAddr):
other = IPAddr(other)
return "%s%s" % (other, self)
def __hash__(self):
# should be the same as by string (because of possible compare with string):
return hash(self.ntoa)
#return hash(self._addr)^hash((self._plen<<16)|self._family)
@property
def hexdump(self):
"""Hex representation of the IP address (for debug purposes)
"""
if self._family == socket.AF_INET:
return "%08x" % self._addr
elif self._family == socket.AF_INET6:
return "%032x" % self._addr
else:
return ""
# TODO: could be lazily evaluated
@property
def ntoa(self):
""" represent IP object as text like the deprecated
C pendant inet.ntoa but address family independent
"""
add = ''
if self.isIPv4:
# convert network to host byte order
binary = struct.pack("!L", self._addr)
if self._plen and self._plen < 32:
add = "/%d" % self._plen
elif self.isIPv6:
# convert network to host byte order
hi = self._addr >> 64
lo = self._addr & 0xFFFFFFFFFFFFFFFF
binary = struct.pack("!QQ", hi, lo)
if self._plen and self._plen < 128:
add = "/%d" % self._plen
else:
return self._raw
return socket.inet_ntop(self._family, binary) + add
def getPTR(self, suffix=None):
""" return the DNS PTR string of the provided IP address object
If "suffix" is provided it will be appended as the second and top
level reverse domain.
If omitted it is implicitly set to the second and top level reverse
domain of the according IP address family
"""
if self.isIPv4:
exploded_ip = self.ntoa.split(".")
if suffix is None:
suffix = "in-addr.arpa."
elif self.isIPv6:
exploded_ip = self.hexdump
if suffix is None:
suffix = "ip6.arpa."
else:
return ""
return "%s.%s" % (".".join(reversed(exploded_ip)), suffix)
def getHost(self):
"""Return the host name (DNS) of the provided IP address object
"""
return DNSUtils.ipToName(self.ntoa)
@property
def isIPv4(self):
"""Either the IP object is of address family AF_INET
"""
return self.family == socket.AF_INET
@property
def isIPv6(self):
"""Either the IP object is of address family AF_INET6
"""
return self.family == socket.AF_INET6
def isInNet(self, net):
"""Return either the IP object is in the provided network
"""
# if it isn't a valid IP address, try DNS resolution
if not net.isValid and net.raw != "":
# Check if IP in DNS
return self in DNSUtils.dnsToIp(net.raw)
if self.family != net.family:
return False
if self.isIPv4:
mask = ~(0xFFFFFFFF >> net.plen)
elif self.isIPv6:
mask = ~(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF >> net.plen)
else:
return False
return (self.addr & mask) == net.addr
def contains(self, ip):
"""Return whether the object (as network) contains given IP
"""
return isinstance(ip, IPAddr) and (ip == self or ip.isInNet(self))
# Pre-calculated map: addr to maskplen
def __getMaskMap():
m6 = (1 << 128)-1
m4 = (1 << 32)-1
mmap = {m6: 128, m4: 32, 0: 0}
m = 0
for i in range(0, 128):
m |= 1 << i
if i < 32:
mmap[m ^ m4] = 32-1-i
mmap[m ^ m6] = 128-1-i
return mmap
MAP_ADDR2MASKPLEN = __getMaskMap()
@property
def maskplen(self):
mplen = 0
if self._maskplen is not None:
return self._maskplen
mplen = IPAddr.MAP_ADDR2MASKPLEN.get(self._addr)
if mplen is None:
raise ValueError("invalid mask %r, no plen representation" % (str(self),))
self._maskplen = mplen
return mplen
@staticmethod
def masktoplen(mask):
"""Convert mask string to prefix length
To be used only for IPv4 masks
"""
return IPAddr(mask).maskplen
@staticmethod
def searchIP(text):
"""Search if text is an IP address, and return it if so, else None
"""
match = IPAddr.IP_4_6_CRE.match(text)
if not match:
return None
ipstr = match.group('IPv4')
if ipstr != '':
return ipstr
return match.group('IPv6')
# An IPv4 compatible IPv6 to be reused
IPAddr.IP6_4COMPAT = IPAddr("::ffff:0:0", 96)
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