/usr/lib/python2.7/dist-packages/M2Crypto/SSL/Checker.py is in python-m2crypto 0.24.0-1.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 | """
SSL peer certificate checking routines
Copyright (c) 2004-2007 Open Source Applications Foundation.
All rights reserved.
Copyright 2008 Heikki Toivonen. All rights reserved.
"""
__all__ = ['SSLVerificationError', 'NoCertificate', 'WrongCertificate',
'WrongHost', 'Checker']
from M2Crypto import m2
import socket
import re
class SSLVerificationError(Exception):
pass
class NoCertificate(SSLVerificationError):
pass
class WrongCertificate(SSLVerificationError):
pass
class WrongHost(SSLVerificationError):
def __init__(self, expectedHost, actualHost, fieldName='commonName'):
"""
This exception will be raised if the certificate returned by the
peer was issued for a different host than we tried to connect to.
This could be due to a server misconfiguration or an active attack.
@param expectedHost: The name of the host we expected to find in the
certificate.
@param actualHost: The name of the host we actually found in the
certificate.
@param fieldName: The field name where we noticed the error. This
should be either 'commonName' or 'subjectAltName'.
"""
if fieldName not in ('commonName', 'subjectAltName'):
raise ValueError('Unknown fieldName, should be either commonName or subjectAltName')
SSLVerificationError.__init__(self)
self.expectedHost = expectedHost
self.actualHost = actualHost
self.fieldName = fieldName
def __str__(self):
s = 'Peer certificate %s does not match host, expected %s, got %s' \
% (self.fieldName, self.expectedHost, self.actualHost)
if isinstance(s, unicode):
s = s.encode('utf8')
return s
class Checker:
numericIpMatch = re.compile('^[0-9]+(\.[0-9]+)*$')
def __init__(self, host=None, peerCertHash=None, peerCertDigest='sha1'):
self.host = host
self.fingerprint = peerCertHash
self.digest = peerCertDigest
def __call__(self, peerCert, host=None):
if peerCert is None:
raise NoCertificate('peer did not return certificate')
if host is not None:
self.host = host
if self.fingerprint:
if self.digest not in ('sha1', 'md5'):
raise ValueError('unsupported digest "%s"' %(self.digest))
if self.digest == 'sha1':
expected_len = 40
elif self.digest == 'md5':
expected_len = 32
else:
raise ValueError('Unexpected digest {0}'.format(self.digest))
if len(self.fingerprint) != expected_len:
raise WrongCertificate(
'''peer certificate fingerprint length does not match
fingerprint: {0}
expected = {1}
observed = {2}'''.format(self.fingerprint,
expected_len,
len(self.fingerprint)))
expected_fingerprint = self.fingerprint
observed_fingerprint = peerCert.get_fingerprint(md=self.digest)
if observed_fingerprint != expected_fingerprint:
raise WrongCertificate('''
peer certificate fingerprint does not match
expected = {0},
observed = {1}'''.format(expected_fingerprint,
observed_fingerprint))
if self.host:
hostValidationPassed = False
self.useSubjectAltNameOnly = False
# subjectAltName=DNS:somehost[, ...]*
try:
subjectAltName = peerCert.get_ext('subjectAltName').get_value()
if self._splitSubjectAltName(self.host, subjectAltName):
hostValidationPassed = True
elif self.useSubjectAltNameOnly:
raise WrongHost(expectedHost=self.host,
actualHost=subjectAltName,
fieldName='subjectAltName')
except LookupError:
pass
# commonName=somehost[, ...]*
if not hostValidationPassed:
hasCommonName = False
commonNames = ''
for entry in peerCert.get_subject().get_entries_by_nid(m2.NID_commonName):
hasCommonName = True
commonName = entry.get_data().as_text()
if not commonNames:
commonNames = commonName
else:
commonNames += ',' + commonName
if self._match(self.host, commonName):
hostValidationPassed = True
break
if not hasCommonName:
raise WrongCertificate('no commonName in peer certificate')
if not hostValidationPassed:
raise WrongHost(expectedHost=self.host,
actualHost=commonNames,
fieldName='commonName')
return True
def _splitSubjectAltName(self, host, subjectAltName):
"""
>>> check = Checker()
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='DNS:my.example.com')
True
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='DNS:*.example.com')
True
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='DNS:m*.example.com')
True
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='DNS:m*ample.com')
False
>>> check.useSubjectAltNameOnly
True
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='DNS:m*ample.com, othername:<unsupported>')
False
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='DNS:m*ample.com, DNS:my.example.org')
False
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='DNS:m*ample.com, DNS:my.example.com')
True
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='DNS:my.example.com, DNS:my.example.org')
True
>>> check.useSubjectAltNameOnly
True
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='')
False
>>> check._splitSubjectAltName(host='my.example.com', subjectAltName='othername:<unsupported>')
False
>>> check.useSubjectAltNameOnly
False
"""
self.useSubjectAltNameOnly = False
for certHost in subjectAltName.split(','):
certHost = certHost.lower().strip()
if certHost[:4] == 'dns:':
self.useSubjectAltNameOnly = True
if self._match(host, certHost[4:]):
return True
elif certHost[:11] == 'ip address:':
self.useSubjectAltNameOnly = True
if self._matchIPAddress(host, certHost[11:]):
return True
return False
def _match(self, host, certHost):
"""
>>> check = Checker()
>>> check._match(host='my.example.com', certHost='my.example.com')
True
>>> check._match(host='my.example.com', certHost='*.example.com')
True
>>> check._match(host='my.example.com', certHost='m*.example.com')
True
>>> check._match(host='my.example.com', certHost='m*.EXAMPLE.com')
True
>>> check._match(host='my.example.com', certHost='m*ample.com')
False
>>> check._match(host='my.example.com', certHost='*.*.com')
False
>>> check._match(host='1.2.3.4', certHost='1.2.3.4')
True
>>> check._match(host='1.2.3.4', certHost='*.2.3.4')
False
>>> check._match(host='1234', certHost='1234')
True
"""
# XXX See RFC 2818 and 3280 for matching rules, this is may not
# XXX yet be complete.
host = host.lower()
certHost = certHost.lower()
if host == certHost:
return True
if certHost.count('*') > 1:
# Not sure about this, but being conservative
return False
if self.numericIpMatch.match(host) or \
self.numericIpMatch.match(certHost.replace('*', '')):
# Not sure if * allowed in numeric IP, but think not.
return False
if certHost.find('\\') > -1:
# Not sure about this, maybe some encoding might have these.
# But being conservative for now, because regex below relies
# on this.
return False
# Massage certHost so that it can be used in regex
certHost = certHost.replace('.', '\.')
certHost = certHost.replace('*', '[^\.]*')
if re.compile('^%s$' %(certHost)).match(host):
return True
return False
def _matchIPAddress(self, host, certHost):
"""
>>> check = Checker()
>>> check._matchIPAddress(host='my.example.com', certHost='my.example.com')
False
>>> check._matchIPAddress(host='1.2.3.4', certHost='1.2.3.4')
True
>>> check._matchIPAddress(host='1.2.3.4', certHost='*.2.3.4')
False
>>> check._matchIPAddress(host='1.2.3.4', certHost='1.2.3.40')
False
>>> check._matchIPAddress(host='::1', certHost='::1')
True
>>> check._matchIPAddress(host='::1', certHost='0:0:0:0:0:0:0:1')
True
>>> check._matchIPAddress(host='::1', certHost='::2')
False
"""
try:
canonical = socket.getaddrinfo(host, 0, 0, socket.SOCK_STREAM, 0,
socket.AI_NUMERICHOST)
certCanonical = socket.getaddrinfo(certHost, 0, 0,
socket.SOCK_STREAM, 0,
socket.AI_NUMERICHOST)
except:
return False
return canonical == certCanonical
if __name__ == '__main__':
import doctest
doctest.testmod()
|