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-rw-r--r--urllib3/packages/ssl_match_hostname/_implementation.py105
1 files changed, 105 insertions, 0 deletions
diff --git a/urllib3/packages/ssl_match_hostname/_implementation.py b/urllib3/packages/ssl_match_hostname/_implementation.py
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+++ b/urllib3/packages/ssl_match_hostname/_implementation.py
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+"""The match_hostname() function from Python 3.3.3, essential when using SSL."""
+
+# Note: This file is under the PSF license as the code comes from the python
+# stdlib. http://docs.python.org/3/license.html
+
+import re
+
+__version__ = '3.4.0.2'
+
+class CertificateError(ValueError):
+ pass
+
+
+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")