JezK
Edit File: ssl_support.py
import os import socket import atexit import re import functools from setuptools.extern.six.moves import urllib, http_client, map, filter from pkg_resources import ResolutionError, ExtractionError try: import ssl except ImportError: ssl = None __all__ = [ 'VerifyingHTTPSHandler', 'find_ca_bundle', 'is_available', 'cert_paths', 'opener_for' ] cert_paths = """ /etc/pki/tls/certs/ca-bundle.crt /etc/ssl/certs/ca-certificates.crt /usr/share/ssl/certs/ca-bundle.crt /usr/local/share/certs/ca-root.crt /etc/ssl/cert.pem /System/Library/OpenSSL/certs/cert.pem /usr/local/share/certs/ca-root-nss.crt /etc/ssl/ca-bundle.pem """.strip().split() try: HTTPSHandler = urllib.request.HTTPSHandler HTTPSConnection = http_client.HTTPSConnection except AttributeError: HTTPSHandler = HTTPSConnection = object is_available = ssl is not None and object not in (HTTPSHandler, HTTPSConnection) try: from ssl import CertificateError, match_hostname except ImportError: try: from backports.ssl_match_hostname import CertificateError from backports.ssl_match_hostname import match_hostname except ImportError: CertificateError = None match_hostname = None if not CertificateError: class CertificateError(ValueError): pass if not match_hostname: def _dnsname_match(dn, hostname, max_wildcards=1): """Matching according to RFC 6125, section 6.4.3 https://tools.ietf.org/html/rfc6125#section-6.4.3 """ pats = [] if not dn: return False # Ported from python3-syntax: # leftmost, *remainder = dn.split(r'.') parts = dn.split(r'.') leftmost = parts[0] remainder = parts[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): """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") 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") class VerifyingHTTPSHandler(HTTPSHandler): """Simple verifying handler: no auth, subclasses, timeouts, etc.""" def __init__(self, ca_bundle): self.ca_bundle = ca_bundle HTTPSHandler.__init__(self) def https_open(self, req): return self.do_open( lambda host, **kw: VerifyingHTTPSConn(host, self.ca_bundle, **kw), req ) class VerifyingHTTPSConn(HTTPSConnection): """Simple verifying connection: no auth, subclasses, timeouts, etc.""" def __init__(self, host, ca_bundle, **kw): HTTPSConnection.__init__(self, host, **kw) self.ca_bundle = ca_bundle def connect(self): sock = socket.create_connection( (self.host, self.port), getattr(self, 'source_address', None) ) # Handle the socket if a (proxy) tunnel is present if hasattr(self, '_tunnel') and getattr(self, '_tunnel_host', None): self.sock = sock self._tunnel() # http://bugs.python.org/issue7776: Python>=3.4.1 and >=2.7.7 # change self.host to mean the proxy server host when tunneling is # being used. Adapt, since we are interested in the destination # host for the match_hostname() comparison. actual_host = self._tunnel_host else: actual_host = self.host if hasattr(ssl, 'create_default_context'): ctx = ssl.create_default_context(cafile=self.ca_bundle) self.sock = ctx.wrap_socket(sock, server_hostname=actual_host) else: # This is for python < 2.7.9 and < 3.4? self.sock = ssl.wrap_socket( sock, cert_reqs=ssl.CERT_REQUIRED, ca_certs=self.ca_bundle ) try: match_hostname(self.sock.getpeercert(), actual_host) except CertificateError: self.sock.shutdown(socket.SHUT_RDWR) self.sock.close() raise def opener_for(ca_bundle=None): """Get a urlopen() replacement that uses ca_bundle for verification""" return urllib.request.build_opener( VerifyingHTTPSHandler(ca_bundle or find_ca_bundle()) ).open # from jaraco.functools def once(func): @functools.wraps(func) def wrapper(*args, **kwargs): if not hasattr(func, 'always_returns'): func.always_returns = func(*args, **kwargs) return func.always_returns return wrapper @once def get_win_certfile(): try: import wincertstore except ImportError: return None class CertFile(wincertstore.CertFile): def __init__(self): super(CertFile, self).__init__() atexit.register(self.close) def close(self): try: super(CertFile, self).close() except OSError: pass _wincerts = CertFile() _wincerts.addstore('CA') _wincerts.addstore('ROOT') return _wincerts.name def find_ca_bundle(): """Return an existing CA bundle path, or None""" extant_cert_paths = filter(os.path.isfile, cert_paths) return ( get_win_certfile() or next(extant_cert_paths, None) or _certifi_where() ) def _certifi_where(): try: return __import__('certifi').where() except (ImportError, ResolutionError, ExtractionError): pass