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# Copyright 2009 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Utility functions related to IP Addresses & Hostnames."""
# TODO(tstromberg): Investigate replacement with ipaddr library
__author__ = 'tstromberg@google.com (Thomas Stromberg)'
import re
import zlib
# TODO(tstromberg): Find a way to combine the following two regexps.
# Used to decide whether or not to benchmark a name
INTERNAL_RE = re.compile('^0|\.pro[md]z*\.|\.corp|\.bor|\.hot$|internal|dmz|'
'\._[ut][dc]p\.|intra|\.\w$|\.\w{5,}$', re.IGNORECASE)
# Used to decide if a hostname should be censored later.
PRIVATE_RE = re.compile('^\w+dc\.|^\w+ds\.|^\w+sv\.|^\w+nt\.|\.corp|internal|'
'intranet|\.local', re.IGNORECASE)
# ^.*[\w-]+\.[\w-]+\.[\w-]+\.[a-zA-Z]+\.$|^[\w-]+\.[\w-]{3,}\.[a-zA-Z]+\.$
FQDN_RE = re.compile('^.*\..*\..*\..*\.$|^.*\.[\w-]*\.\w{3,4}\.$|^[\w-]+\.[\w-]{4,}\.\w+\.')
IP_RE = re.compile('^[0-9.]+$')
def ExtractIPsFromString(ip_string):
"""Return a tuple of ip addressed held in a string."""
ips = []
# IPV6 If this regexp is too loose, see Regexp-IPv6 in CPAN for inspiration.
ips.extend(re.findall('[\dabcdef:]+:[\dabcdef:]+', ip_string, re.IGNORECASE))
ips.extend(re.findall('\d+\.\d+\.\d+\.+\d+', ip_string))
return ips
def ExtractIPTuplesFromString(ip_string):
"""Return a list of (ip, name) tuples for use by NameServer class."""
ip_tuples = []
for ip in ExtractIPsFromString(ip_string):
ip_tuples.append((ip, ip))
return ip_tuples
def IsPrivateHostname(hostname):
"""Basic matching to determine if the hostname is likely to be 'internal'."""
if PRIVATE_RE.search(hostname):
return True
else:
return False
def IsLoopbackIP(ip):
"""Boolean check to see if an IP is private or not.
Args:
ip: str
Returns:
Boolean
"""
if ip.startswith('127.') or ip == '::1':
return True
else:
return False
def IsPrivateIP(ip):
"""Boolean check to see if an IP is private or not.
Args:
ip: str
Returns:
Number of bits that should be preserved (int, or None)
"""
if re.match('^10\.', ip):
return 1
elif re.match('^192\.168', ip):
return 2
elif re.match('^172\.(1[6-9]|2[0-9]|3[0-1])\.', ip):
return 1
else:
return None
def MaskStringWithIPs(string):
"""Mask all private IP addresses listed in a string."""
ips = ExtractIPsFromString(string)
for ip in ips:
use_bits = IsPrivateIP(ip)
if use_bits:
masked_ip = MaskIPBits(ip, use_bits)
string = string.replace(ip, masked_ip)
return string
def MaskIPBits(ip, use_bits):
"""Mask an IP, but still keep a meaningful checksum."""
ip_parts = ip.split('.')
checksum = zlib.crc32(''.join(ip_parts[use_bits:]))
masked_ip = '.'.join(ip_parts[0:use_bits])
return masked_ip + '.x-' + str(checksum)[-4:]
def MaskPrivateHost(ip, hostname, name):
"""Mask unnamed private IP's."""
# If we have a name not listed as SYS-x.x.x.x, then we're clear.
if name and ip not in name:
# Even if we are listed (Internal 192-0-1 for instance), data can leak via hostname.
if IsPrivateIP(ip):
hostname = 'internal.ip'
return (ip, hostname, name)
use_bits = IsPrivateIP(ip)
if use_bits:
masked_ip = MaskIPBits(ip, use_bits)
masked_hostname = 'internal.ip'
elif IsPrivateHostname(hostname):
masked_ip = MaskIPBits(ip, 2)
masked_hostname = 'internal.name'
else:
masked_ip = ip
masked_hostname = hostname
if 'SYS-' in name:
masked_name = 'SYS-%s' % masked_ip
else:
masked_name = ''
return (masked_ip, masked_hostname, masked_name)
if __name__ == '__main__':
print MaskStringWithIPs('10.0.0.1 has a sharing relationship with 192.168.0.1 and 8.8.8.8')
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