"""The match_hostname() function from Python 3.7.0, essential when using SSL.""" import sys import socket as _socket try: # Divergence: Python-3.7+'s _ssl has this exception type but older Pythons do not from _ssl import SSLCertVerificationError CertificateError = SSLCertVerificationError except: class CertificateError(ValueError): pass __version__ = '3.7.0.1' # Divergence: Added to deal with ipaddess as bytes on python2 def _to_text(obj): if isinstance(obj, str) and sys.version_info < (3,): obj = unicode(obj, encoding='ascii', errors='strict') elif sys.version_info >= (3,) and isinstance(obj, bytes): obj = str(obj, encoding='ascii', errors='strict') return obj def _to_bytes(obj): if isinstance(obj, str) and sys.version_info >= (3,): obj = bytes(obj, encoding='ascii', errors='strict') elif sys.version_info < (3,) and isinstance(obj, unicode): obj = obj.encode('ascii', 'strict') return obj def _dnsname_match(dn, hostname): """Matching according to RFC 6125, section 6.4.3 - Hostnames are compared lower case. - For IDNA, both dn and hostname must be encoded as IDN A-label (ACE). - Partial wildcards like 'www*.example.org', multiple wildcards, sole wildcard or wildcards in labels other then the left-most label are not supported and a CertificateError is raised. - A wildcard must match at least one character. """ if not dn: return False wildcards = dn.count('*') # speed up common case w/o wildcards if not wildcards: return dn.lower() == hostname.lower() if wildcards > 1: # Divergence .format() to percent formatting for Python < 2.6 raise CertificateError( "too many wildcards in certificate DNS name: %s" % repr(dn)) dn_leftmost, sep, dn_remainder = dn.partition('.') if '*' in dn_remainder: # Only match wildcard in leftmost segment. # Divergence .format() to percent formatting for Python < 2.6 raise CertificateError( "wildcard can only be present in the leftmost label: " "%s." % repr(dn)) if not sep: # no right side # Divergence .format() to percent formatting for Python < 2.6 raise CertificateError( "sole wildcard without additional labels are not support: " "%s." % repr(dn)) if dn_leftmost != '*': # no partial wildcard matching # Divergence .format() to percent formatting for Python < 2.6 raise CertificateError( "partial wildcards in leftmost label are not supported: " "%s." % repr(dn)) hostname_leftmost, sep, hostname_remainder = hostname.partition('.') if not hostname_leftmost or not sep: # wildcard must match at least one char return False return dn_remainder.lower() == hostname_remainder.lower() def _inet_paton(ipname): """Try to convert an IP address to packed binary form Supports IPv4 addresses on all platforms and IPv6 on platforms with IPv6 support. """ # inet_aton() also accepts strings like '1' # Divergence: We make sure we have native string type for all python versions try: b_ipname = _to_bytes(ipname) except UnicodeError: raise ValueError("%s must be an all-ascii string." % repr(ipname)) # Set ipname in native string format if sys.version_info < (3,): n_ipname = b_ipname else: n_ipname = ipname if n_ipname.count('.') == 3: try: return _socket.inet_aton(n_ipname) # Divergence: OSError on late python3. socket.error earlier. # Null bytes generate ValueError on python3(we want to raise # ValueError anyway), TypeError # earlier except (OSError, _socket.error, TypeError): pass try: return _socket.inet_pton(_socket.AF_INET6, n_ipname) # Divergence: OSError on late python3. socket.error earlier. # Null bytes generate ValueError on python3(we want to raise # ValueError anyway), TypeError # earlier except (OSError, _socket.error, TypeError): # Divergence .format() to percent formatting for Python < 2.6 raise ValueError("%s is neither an IPv4 nor an IP6 " "address." % repr(ipname)) except AttributeError: # AF_INET6 not available pass # Divergence .format() to percent formatting for Python < 2.6 raise ValueError("%s is not an IPv4 address." % repr(ipname)) def _ipaddress_match(ipname, host_ip): """Exact matching of IP addresses. RFC 6125 explicitly doesn't define an algorithm for this (section 1.7.2 - "Out of Scope"). """ # OpenSSL may add a trailing newline to a subjectAltName's IP address ip = _inet_paton(ipname.rstrip()) return ip == host_ip def match_hostname(cert, hostname): """Verify that *cert* (in decoded format as returned by SSLSocket.getpeercert()) matches the *hostname*. RFC 2818 and RFC 6125 rules are followed. The function matches IP addresses rather than dNSNames if hostname is a valid ipaddress string. IPv4 addresses are supported on all platforms. IPv6 addresses are supported on platforms with IPv6 support (AF_INET6 and inet_pton). 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") try: # Divergence: Deal with hostname as bytes host_ip = _inet_paton(_to_text(hostname)) except ValueError: # Not an IP address (common case) host_ip = None except UnicodeError: # Divergence: Deal with hostname as byte strings. # IP addresses should be all ascii, so we consider it not # an IP address if this fails host_ip = None dnsnames = [] san = cert.get('subjectAltName', ()) for key, value in san: if key == 'DNS': if host_ip is None and _dnsname_match(value, hostname): return dnsnames.append(value) elif key == 'IP Address': if host_ip is not None and _ipaddress_match(value, host_ip): 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")