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- import os
- import socket
- import atexit
- import re
-
- import pkg_resources
- from pkg_resources import ResolutionError, ExtractionError
- from setuptools.compat import urllib2
-
- 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
- """.strip().split()
-
-
- HTTPSHandler = HTTPSConnection = object
-
- for what, where in (
- ('HTTPSHandler', ['urllib2','urllib.request']),
- ('HTTPSConnection', ['httplib', 'http.client']),
- ):
- for module in where:
- try:
- exec("from %s import %s" % (module, what))
- except ImportError:
- pass
-
- 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
-
- http://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
-
- 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 urllib2.build_opener(
- VerifyingHTTPSHandler(ca_bundle or find_ca_bundle())
- ).open
-
-
- _wincerts = None
-
- def get_win_certfile():
- global _wincerts
- if _wincerts is not None:
- return _wincerts.name
-
- try:
- from wincertstore import CertFile
- except ImportError:
- return None
-
- class MyCertFile(CertFile):
- def __init__(self, stores=(), certs=()):
- CertFile.__init__(self)
- for store in stores:
- self.addstore(store)
- self.addcerts(certs)
- atexit.register(self.close)
-
- _wincerts = MyCertFile(stores=['CA', 'ROOT'])
- return _wincerts.name
-
-
- def find_ca_bundle():
- """Return an existing CA bundle path, or None"""
- if os.name=='nt':
- return get_win_certfile()
- else:
- for cert_path in cert_paths:
- if os.path.isfile(cert_path):
- return cert_path
- try:
- return pkg_resources.resource_filename('certifi', 'cacert.pem')
- except (ImportError, ResolutionError, ExtractionError):
- return None
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