134 lines
5.2 KiB
Python
134 lines
5.2 KiB
Python
"""
|
|
"""
|
|
|
|
# Created on 2014.10.05
|
|
#
|
|
# Author: Giovanni Cannata
|
|
#
|
|
# Copyright 2014 - 2020 Giovanni Cannata
|
|
#
|
|
# This file is part of ldap3.
|
|
#
|
|
# ldap3 is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU Lesser General Public License as published
|
|
# by the Free Software Foundation, either version 3 of the License, or
|
|
# (at your option) any later version.
|
|
#
|
|
# ldap3 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 Lesser General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU Lesser General Public License
|
|
# along with ldap3 in the COPYING and COPYING.LESSER files.
|
|
# If not, see <http://www.gnu.org/licenses/>.
|
|
import re
|
|
from ..utils.log import log, log_enabled, NETWORK
|
|
|
|
try:
|
|
from backports.ssl_match_hostname import match_hostname, CertificateError
|
|
except ImportError:
|
|
class CertificateError(ValueError): # fix for Python 2, code from Python 3.5 standard library
|
|
pass
|
|
|
|
|
|
def _dnsname_match(dn, hostname, max_wildcards=1):
|
|
"""Backported from Python 3.4.3 standard library
|
|
|
|
Matching according to RFC 6125, section 6.4.3
|
|
|
|
http://tools.ietf.org/html/rfc6125#section-6.4.3
|
|
"""
|
|
if log_enabled(NETWORK):
|
|
log(NETWORK, "matching dn %s with hostname %s", dn, hostname)
|
|
pats = []
|
|
if not dn:
|
|
return False
|
|
|
|
pieces = dn.split(r'.')
|
|
leftmost = pieces[0]
|
|
remainder = pieces[1:]
|
|
|
|
wildcards = leftmost.count('*')
|
|
if wildcards > max_wildcards:
|
|
# Issue #17980: avoid denials of service by refusing more
|
|
# than one wildcard per fragment. A survey of established
|
|
# policy among SSL implementations showed it to be a
|
|
# reasonable choice.
|
|
raise CertificateError(
|
|
"too many wildcards in certificate DNS name: " + repr(dn))
|
|
|
|
# speed up common case w/o wildcards
|
|
if not wildcards:
|
|
return dn.lower() == hostname.lower()
|
|
|
|
# RFC 6125, section 6.4.3, subitem 1.
|
|
# The client SHOULD NOT attempt to match a presented identifier in which
|
|
# the wildcard character comprises a label other than the left-most label.
|
|
if leftmost == '*':
|
|
# When '*' is a fragment by itself, it matches a non-empty dotless
|
|
# fragment.
|
|
pats.append('[^.]+')
|
|
elif leftmost.startswith('xn--') or hostname.startswith('xn--'):
|
|
# RFC 6125, section 6.4.3, subitem 3.
|
|
# The client SHOULD NOT attempt to match a presented identifier
|
|
# where the wildcard character is embedded within an A-label or
|
|
# U-label of an internationalized domain name.
|
|
pats.append(re.escape(leftmost))
|
|
else:
|
|
# Otherwise, '*' matches any dotless string, e.g. www*
|
|
pats.append(re.escape(leftmost).replace(r'\*', '[^.]*'))
|
|
|
|
# add the remaining fragments, ignore any wildcards
|
|
for frag in remainder:
|
|
pats.append(re.escape(frag))
|
|
|
|
pat = re.compile(r'\A' + r'\.'.join(pats) + r'\Z', re.IGNORECASE)
|
|
return pat.match(hostname)
|
|
|
|
|
|
def match_hostname(cert, hostname):
|
|
"""Backported from Python 3.4.3 standard library.
|
|
|
|
Verify that *cert* (in decoded format as returned by
|
|
SSLSocket.getpeercert()) matches the *hostname*. RFC 2818 and RFC 6125
|
|
rules are followed, but IP addresses are not accepted for *hostname*.
|
|
|
|
CertificateError is raised on failure. On success, the function
|
|
returns nothing.
|
|
"""
|
|
|
|
if not cert:
|
|
raise ValueError("empty or no certificate, match_hostname needs a "
|
|
"SSL socket or SSL context with either "
|
|
"CERT_OPTIONAL or CERT_REQUIRED")
|
|
dnsnames = []
|
|
san = cert.get('subjectAltName', ())
|
|
for key, value in san:
|
|
if key == 'DNS':
|
|
if _dnsname_match(value, hostname):
|
|
return
|
|
dnsnames.append(value)
|
|
if not dnsnames:
|
|
# The subject is only checked when there is no dNSName entry
|
|
# in subjectAltName
|
|
for sub in cert.get('subject', ()):
|
|
for key, value in sub:
|
|
# XXX according to RFC 2818, the most specific Common Name
|
|
# must be used.
|
|
if key == 'commonName':
|
|
if _dnsname_match(value, hostname):
|
|
return
|
|
dnsnames.append(value)
|
|
if len(dnsnames) > 1:
|
|
raise CertificateError("hostname %r "
|
|
"doesn't match either of %s"
|
|
% (hostname, ', '.join(map(repr, dnsnames))))
|
|
elif len(dnsnames) == 1:
|
|
raise CertificateError("hostname %r "
|
|
"doesn't match %r"
|
|
% (hostname, dnsnames[0]))
|
|
else:
|
|
raise CertificateError("no appropriate commonName or "
|
|
"subjectAltName fields were found")
|