diff options
Diffstat (limited to 'Lib/ssl.py')
| -rw-r--r-- | Lib/ssl.py | 106 |
1 files changed, 65 insertions, 41 deletions
@@ -90,8 +90,6 @@ ALERT_DESCRIPTION_BAD_CERTIFICATE_HASH_VALUE ALERT_DESCRIPTION_UNKNOWN_PSK_IDENTITY """ -import ipaddress -import re import sys import os from collections import namedtuple @@ -160,6 +158,7 @@ if sys.platform == "win32": from socket import socket, AF_INET, SOCK_STREAM, create_connection from socket import SOL_SOCKET, SO_TYPE +import socket as _socket import base64 # for DER-to-PEM translation import errno import warnings @@ -183,55 +182,75 @@ CertificateError = SSLCertVerificationError def _dnsname_match(dn, hostname): """Matching according to RFC 6125, section 6.4.3 - http://tools.ietf.org/html/rfc6125#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. """ - pats = [] if not dn: return False - leftmost, *remainder = dn.split(r'.') + wildcards = dn.count('*') + # speed up common case w/o wildcards + if not wildcards: + return dn.lower() == hostname.lower() + + if wildcards > 1: + raise CertificateError( + "too many wildcards in certificate DNS name: {!r}.".format(dn)) - wildcards = leftmost.count('*') - if wildcards == 1 and len(leftmost) > 1: + dn_leftmost, sep, dn_remainder = dn.partition('.') + + if '*' in dn_remainder: # Only match wildcard in leftmost segment. raise CertificateError( - "wildcard can only be present in the leftmost segment: " + repr(dn)) + "wildcard can only be present in the leftmost label: " + "{!r}.".format(dn)) - if wildcards > 1: - # 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. + if not sep: + # no right side raise CertificateError( - "too many wildcards in certificate DNS name: " + repr(dn)) + "sole wildcard without additional labels are not support: " + "{!r}.".format(dn)) - # speed up common case w/o wildcards - if not wildcards: - return dn.lower() == hostname.lower() + if dn_leftmost != '*': + # no partial wildcard matching + raise CertificateError( + "partial wildcards in leftmost label are not supported: " + "{!r}.".format(dn)) - # 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'\*', '[^.]*')) + 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() - # 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 _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' + if ipname.count('.') == 3: + try: + return _socket.inet_aton(ipname) + except OSError: + pass + + try: + return _socket.inet_pton(_socket.AF_INET6, ipname) + except OSError: + raise ValueError("{!r} is neither an IPv4 nor an IP6 " + "address.".format(ipname)) + except AttributeError: + # AF_INET6 not available + pass + + raise ValueError("{!r} is not an IPv4 address.".format(ipname)) def _ipaddress_match(ipname, host_ip): @@ -241,14 +260,19 @@ def _ipaddress_match(ipname, host_ip): (section 1.7.2 - "Out of Scope"). """ # OpenSSL may add a trailing newline to a subjectAltName's IP address - ip = ipaddress.ip_address(ipname.rstrip()) + 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, but IP addresses are not accepted for *hostname*. + 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. @@ -258,7 +282,7 @@ def match_hostname(cert, hostname): "SSL socket or SSL context with either " "CERT_OPTIONAL or CERT_REQUIRED") try: - host_ip = ipaddress.ip_address(hostname) + host_ip = _inet_paton(hostname) except ValueError: # Not an IP address (common case) host_ip = None |