62 lines
2.1 KiB
Python
62 lines
2.1 KiB
Python
"""The match_hostname() function from Python 3.2, essential when using SSL."""
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import re
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__version__ = '3.2.2'
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class CertificateError(ValueError):
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pass
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def _dnsname_to_pat(dn):
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pats = []
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for frag in dn.split(r'.'):
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if frag == '*':
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# When '*' is a fragment by itself, it matches a non-empty dotless
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# fragment.
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pats.append('[^.]+')
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else:
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# Otherwise, '*' matches any dotless fragment.
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frag = re.escape(frag)
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pats.append(frag.replace(r'\*', '[^.]*'))
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return re.compile(r'\A' + r'\.'.join(pats) + r'\Z', re.IGNORECASE)
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def match_hostname(cert, hostname):
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"""Verify that *cert* (in decoded format as returned by
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SSLSocket.getpeercert()) matches the *hostname*. RFC 2818 rules
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are mostly followed, but IP addresses are not accepted for *hostname*.
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CertificateError is raised on failure. On success, the function
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returns nothing.
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"""
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if not cert:
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raise ValueError("empty or no certificate")
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dnsnames = []
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san = cert.get('subjectAltName', ())
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for key, value in san:
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if key == 'DNS':
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if _dnsname_to_pat(value).match(hostname):
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return
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dnsnames.append(value)
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if not dnsnames:
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# The subject is only checked when there is no dNSName entry
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# in subjectAltName
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for sub in cert.get('subject', ()):
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for key, value in sub:
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# XXX according to RFC 2818, the most specific Common Name
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# must be used.
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if key == 'commonName':
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if _dnsname_to_pat(value).match(hostname):
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return
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dnsnames.append(value)
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if len(dnsnames) > 1:
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raise CertificateError("hostname %r "
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"doesn't match either of %s"
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% (hostname, ', '.join(map(repr, dnsnames))))
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elif len(dnsnames) == 1:
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raise CertificateError("hostname %r "
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"doesn't match %r"
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% (hostname, dnsnames[0]))
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else:
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raise CertificateError("no appropriate commonName or "
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"subjectAltName fields were found")
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